JP2002193514A - Paper discharging device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a paper discharging device allowing reliably discharging a sheet without damaging it such as forming stripe marks or stiffening free from curling to improve stacking performance of the sheet to a paper discharging unit. SOLUTION: This paper discharging device 7 sandwiches and conveys the sheet S by using a pair of rollers formed of a drive roller 11 and a driven roller 12 facing/abutting on the drive roller 11 for operatively associated with it for discharging the sheet S toward a predetermined position. The pair of rollers has different discharging angles θ of the sheet S at positions between ends in the width direction of the sheet S.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a paper discharge device and an image forming apparatus, and more particularly, to a configuration of a roller pair used for feeding out a sheet toward a paper discharge tray.

[0002]

2. Description of the Related Art In an image forming apparatus such as a copying machine, a facsimile, a printer, and a printing machine, after fixing a sheet of recording paper or the like carrying an image transferred from a photoconductor as a latent image carrier, after fixing. , And discharge the paper toward a paper discharge tray. Conventionally, a configuration is known in which a pair of rollers is used as a configuration for discharging a sheet, and the sheet is moved in a tangential direction obtained at a contact position between the rollers while nipping the sheet by the pair of rollers.
Regardless of the type, sheets discharged to the paper output tray are discharged to an appropriate position on the paper output tray,
This is desired in the sense that post-processing such as rearrangement is not required so as not to deteriorate the so-called stacking property.

[0003] As a structure for improving the stacking property, Japanese Unexamined Utility Model Publication No. 3-102552 and Japanese Unexamined Patent Application Publication No. 7-237 are disclosed.
There is a configuration disclosed in Japanese Patent Publication No. 65-65. 3-102
Japanese Patent Application Publication No. 552 discloses a configuration in which a blade made of an elastic body is provided on one of a pair of discharge rollers used for discharging a sheet, and the rear end of the sheet over the discharge roller can be forcibly pushed out. I have. A plurality of discharge rollers having blades are provided in the sheet width direction corresponding to a direction perpendicular to the sheet discharge direction, and the sheet is appropriately pushed out of the discharge tray by pushing the sheet rear end evenly in the sheet width direction. It can be discharged to a location.

Japanese Patent Application Laid-Open No. Hei 7-23765 discloses a driving roller and a driven roller that comes into contact with the driving roller. The driving roller has an end in the axial direction having a convex portion larger than the outer diameter of the driving roller. A configuration in which a plurality of paddle portions are provided along the circumferential direction is disclosed. The drive roller can reliably discharge the sheet to the discharge tray by hooking the trailing end of the discharged sheet on a paddle and kicking it off.

[0005]

In the construction disclosed in each of the publications, a radial step is provided on the peripheral surface of the roller, and the sheet is bent and deformed at this step sub to form a kink.
The waist is attached to increase the bending rigidity so that the sheet does not curl on the paper discharge tray. However, in the configuration disclosed in the above-mentioned publication, although the elasticity is used for the portion for pushing out the rear end of the seat, the elasticity of the seat is efficiently increased. Becomes too large, and on the contrary, a streak trace is generated when the seat is stiffened. On the other hand, if the amount of deformation is reduced, the occurrence of defects on the sheet can be reduced, but insufficient seating makes it easy for jams to occur due to curl and the like, and the stackability of the discharged sheet deteriorates Resulting in. For this reason, post-processing such as realignment of the sheet group obtained in the image forming apparatus is required, and the user is forced to perform unnecessary work for image formation.

SUMMARY OF THE INVENTION In view of the above-mentioned problems in the conventional sheet discharging apparatus and the image forming apparatus using the same, an object of the present invention is to provide a sheet discharging property, that is, a so-called curl without causing damage such as stripes on the sheet. An object of the present invention is to provide a sheet discharging device and an image forming apparatus having a configuration capable of improving the stacking property of sheets on a sheet discharging portion by reliably performing a stiffening operation.

[0007]

According to the first aspect of the present invention,
In a sheet discharging device for nipping and conveying a sheet using a pair of rollers composed of a driving roller and a driven roller capable of interlocking with and opposing to the driving roller and discharging the sheet to a predetermined position, a pair of rollers for nipping and conveying the sheet Is characterized in that the discharge angle of the sheet is different between an end portion and a position between the end portions in the width direction of the sheet.

According to a second aspect of the present invention, a pair of rollers positioned at both ends in the width direction of the sheet and a pair of rollers positioned between both ends are different in a position where the driven roller faces the driving roller in the circumferential direction. It is characterized by having.

According to a third aspect of the present invention, the roller pair includes:
At least three positions are provided along the width direction of the sheet, and among the roller pairs, the roller pairs located at both ends in the width direction of the sheet are configured to set the discharge angle of the sheet between both ends in the width direction of the sheet. It is characterized in that the angle is set to be higher than the discharge angle of the located roller pair.

According to a fourth aspect of the present invention, the pressing force on the roller pair at the widthwise end of the sheet is set to be larger than that of the roller pair located between the ends.

According to a fifth aspect of the present invention, of the driving roller and the driven roller constituting the roller pair, a roller located on the lower peripheral surface side of one of the rollers is provided with a kicking portion on its outer peripheral surface. It is characterized by having.

According to a sixth aspect of the present invention, a plurality of the kicking portions are provided along the circumferential direction on the outer side outside the end face of the roller facing in the axial direction of the roller and protrude radially outward. It is characterized by comprising.

According to a seventh aspect of the present invention, one of the rollers in the pair of rollers corresponds to a driving roller, and the other roller corresponds to a driven roller positioned opposite to a lower peripheral surface of the driving roller. The image forming apparatus is characterized in that the driven roller is formed of a resin-made roller, and the driven roller is formed of a resin-made roller.

According to an eighth aspect of the present invention, there is provided a paper discharge device according to one of the first to seventh aspects.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be described below with reference to the embodiments shown in the drawings. FIG. 1 shows one of image forming apparatuses using a sheet discharging apparatus according to an embodiment of the present invention. The image forming apparatus shown in FIG. 1 is a copying machine.
In the present invention, the present invention is not limited to the copying machine, but includes a facsimile machine, a printer, a printing machine, and the like.

[0016] In FIG. 1, the copying machine 1 is an image forming apparatus, a photosensitive drum 2 is equipped therein. Although not shown, a charging device, a writing device, and the like for performing image forming processing along the rotation direction are provided around the photoconductor 2.
The developing device is collectively arranged in the process unit 3, and the process unit 3 is also provided with a cleaning device for removing a developer remaining on the photoconductor 2 and a residual electrification after the transfer process to the photoconductor 2. Have been. The transfer process is performed by the transfer device 5 that faces the photosensitive member 2 across the conveyance path of the sheet t fed from the sheet feeding device 4.

The sheet feeding device 4 includes a sheet feeding cassette 4A capable of storing sheets S, and a sheet table 4 in the sheet feeding cassette 4A.
A feeding roller 4B which can be fed out by contacting the uppermost one of the sheets placed on A1, a separating member 4C for feeding out only the uppermost sheet in cooperation with the feeding roller 4B, and a registration roller 4D as a main part. The sheet feeding device 4 is capable of feeding a sheet of a nonstandard size that cannot be accommodated in the sheet feeding cassette 4A1 to the transfer position of the photoconductor 2 separately from the sheet feeding cassette 4A provided in the copying machine 1 in a permanent manner. As a configuration for this purpose, a paper feed tray 1A is provided on the wall of the copying machine main body so as to be able to be partially turned upside down, and a feeding roller (for convenience, 4B ')
And a separating member (for convenience, indicated by reference numeral 4C ′).

A fixing device 6 is provided at a position where the sheet fed from the transfer position where the photosensitive member 2 and the transfer device 5 face each other moves. The fixing device 6 is composed of a roller pair including a heating roller 6 and a trace pressure roller 6B, and the toner carried on the sheet by heat and pressure when the sheet moves between the rollers that oppose each other. The image is heat fused to the sheet.

A sheet discharging device 7 is provided at a position where the sheet having been fixed by the fixing device 6 moves, and the sheet discharging device 7 is disposed near the sheet discharging device 7 continuously in the rear of the sheet moving direction indicated by a dashed line. A paper discharge tray 8 is disposed.

In the copying machine 1 having the above configuration,
While the photoreceptor 2 uniformly charged by the charging device 3 rotates, an electrostatic latent image is formed by the writing device 4 and the developing device 5 processes the electrostatic latent image into a visible image. The toner image forming a visible image is transferred to the sheet fed from the sheet feeding device 4 via the sheet feeding device. The sheet to which the toner image has been transferred is discharged onto a discharge tray 8 by a discharge device 7 after the toner image is heated and fixed by a fixing device 6.

In FIG. 1, when the sheet discharged toward the paper discharge tray 8 is relatively thick, it follows the shape of the paper discharge tray 8 as indicated by a dashed line, in other words, the load on the paper discharge tray 8. On the other hand, the thin sheet is ejected in a state parallel to the placing surface, while a thin sheet is stiffened in the moving direction due to the shape of the conveyance path on the way to the sheet ejection device 7, that is, the presence of a curved path. As indicated by the dashed line, curl occurs on the paper discharge tray 8, and the paper is not smoothly discharged to the rear end in the discharge direction on the paper discharge tray 8, so-called a jam is easily caused. Even in such a case, the discharge of the subsequent sheet is likely to be hindered due to the remaining curl.

The configuration of the paper discharging device 7 in this embodiment is shown in FIGS. FIG.
It is a schematic diagram for explaining the configuration of the main part in,
In FIG. 1, a paper discharging device 7 includes a driving roller 9 having an axial direction parallel to a sheet width direction corresponding to a direction perpendicular to a sheet discharging direction (a direction indicated by a dashed line in FIG. 1) and a driving roller 9 opposed thereto. and a roller pair composed of interlocking capable driven roller 10 Metropolitan contacts.

In this embodiment, at least three points along the axial direction of the drive shaft 9A parallel to the sheet width direction corresponding to the direction perpendicular to the sheet discharge direction indicated by the dashed line in FIG. Drive rollers 9 in four places corresponding to
Are arranged, and the driven rollers 10 face the respective drive rollers 9. The roller pair can pinch and convey the sheet, and each of the roller pairs has a different sheet discharge angle between the roller pair located at the end and the roller pair located between the ends in the width direction of the sheet. . Less than,
This configuration will be described.

In FIG. 2, a drive shaft 9 parallel to the sheet width direction corresponding to a direction perpendicular to the sheet discharge direction (the direction indicated by a dashed line in FIG. 1) and a plurality of drive shafts 9 are arranged in parallel with this. The supporting shafts 10 and 10 'are provided with a pair of rollers including a driving roller 11 and a driven roller 12, and in the present embodiment, each pair of rollers corresponds to at least three positions in the sheet width direction. It is provided in each place.

Among the roller pairs, the roller pairs located at both ends in the width direction of the sheet differ from the roller pairs located between both ends in the width direction in that the opposing position of the driven roller 12 in the circumferential direction of the driving roller 11 is different. I have. FIG. 3 shows a drive roller 11 and a driven roller located between both ends in the width direction and a driven roller (for convenience, a driven roller located at both ends is denoted by reference numeral 12 and a driven roller located between both ends is denoted by reference numeral 12 ′). In the drawing, the driven rollers 12 located at both ends in the width direction are formed by a straight line connecting the centers of the driven rollers 11 (indicated by Y ′ for convenience). It is opposed to a straight line (indicated by Y for convenience) connecting the centers of the rollers 12 ′ and the drive roller 11 by being shifted upward in the circumferential direction by an angle θ.

The driven rollers 12 located at both ends in the width direction of the sheet are shifted upward in the circumferential direction of the drive roller 11 with respect to the driven rollers 12 'located between both ends, so that the driven roller 12 is shifted upward in FIG. And in FIG.
The driven roller 12 'between the both ends is changed in the sheet discharging direction indicated by.
2 is set upward with respect to the discharge direction (the direction indicated by reference numeral F2 in FIGS. 2 and 3).

Since the present embodiment has the above configuration,
The sheet that has reached the sheet discharge device 7 is more likely to bend upward at both ends in the width direction than at both ends. This allows
Since the amount of curving of the sheet at both ends in the width direction is larger than that between both ends, so-called stiffening amount is increased, curling in the discharge direction is less likely to occur, and the sheet curls when discharged on the discharge tray 8. Is gone.

Next, another embodiment according to the embodiment of the present invention will be described. The driven roller 12 located at both ends in the width direction of the sheet and the driven roller 12 ′ located between both ends are supported by the configuration shown in FIGS. 2 to 4, the support shafts 10 of the driven rollers 12 and 12 ′
Reference numeral 10 ′ is rotatably supported by leaf spring supports 13, 13 ′ fixed to an immovable portion of the paper discharge device 7. Since the leaf spring supports 13 and 13 'have substantially the same configuration, the configuration for the driven roller 12 will be described with reference to FIGS. 4 and 5 as follows.

The leaf spring support 13 is made of a sheet metal member bent so as to form a U-shape when viewed from the side, and one piece 13A is a flange piece through which the support shaft 10 can be inserted. The other piece 13B is a support piece which is fastened and held to the immovable part. The leaf spring support 13 for the driven roller 12 located at both ends in the width direction of the sheet drives the driven roller 12 with respect to the leaf spring support 13 ′ for the driven roller 12 ′ located between both ends. Roller 11
Is set to a sufficient size to be positioned upward in the circumferential direction.

The leaf spring support members 13 and 13 'have a habit of expanding in a direction in which each part is separated, and this habit causes the driven rollers 12, 12' to be pressed against the drive roller 11. However, as shown in FIG. 2, the relationship between the pressing force (P1) of the driven roller 12 located at both ends in the width direction of the sheet is greater than the pressing force (P2) of the driven roller 12 ′ located between both ends. It is set to be larger relationship (P1> P2).

Since the present embodiment has the above configuration,
Among the driven rollers 12, 12 ', the pressure covered by the leaf spring support 13 for the driven rollers 12 located at both ends is higher than that for the driven roller 12' located between both ends. Is prevented from being pushed down when the sheet passes, and the driving roller 11
Maintaining the contact pressure of the driven roller 12 against. Thus, it is possible to prevent the degree of bending deformation at both ends in the width direction of the sheet from being reduced, and it is possible to prevent curling from occurring by not reducing the amount of bending at both ends in the width direction. As a result, the sheets discharged to the paper discharge tray 8 are not curled, and the stacking property is not impaired.

Next, another example according to the embodiment of the present invention will be described. The feature of the present embodiment is that a rear end of the sheet discharged by the driven rollers 12 located at both ends is not left on the peripheral surface of the driven roller 12. In FIG. 4, one of a pair of rollers, in this embodiment, a driven roller which is located on the lower peripheral side of the driving roller 11 facing the image surface of the sheet and faces the surface opposite to the image surface of the sheet On the peripheral surfaces of the rollers 12, 12 ', a plurality of kicking portions 14 are formed on one side of the axial end along the circumferential direction, in this embodiment, near the axial outside.

As shown in FIGS. 4 and 5, the kicking portion 14 is formed of a convex portion that projects outward from the outer peripheral surface of the driven roller 12 in the radial direction of the driven roller 12, and has a longitudinal direction in the axial direction. And its forming position is near the axially outer end face of each of the driven rollers 12, 12 '.
The trailing end of the sheet is kicked out and pushed out by the axially extending wall surfaces of the driven rollers 12, 12 '.

Since the present embodiment has the above configuration,
The driven rollers 12, 12 'in each roller pair kick the rear end of the sheet in the sheet discharging direction over the entire area in the width direction.
4 can be kicked off, and the sheet is kicked off by 14
Is forced out. For this reason, it is possible to forcibly prevent the sheet from remaining at the holding position between the pair of rollers. In particular, the roller pair located at both ends in the width direction of the sheet has a longer time in which the trailing end of the sheet separates from the clamping position than the roller pair located between both ends, and thus tends to remain at the clamping position. By being kicked off, it is forced out of the holding position.

The kicking section 14 includes the driven rollers 12, 1
Since it is formed in the vicinity of the axially outer end face in 2 ', the sheet kicked off at that portion is easily spread outward in the width direction, and the curl on the paper discharge tray 8 is maintained while maintaining the seated posture. Will be suppressed. As a result, it is possible to completely prevent the trailing edge of the sheet from remaining at the nipping position of the roller pair due to the rubbing resistance generated when the leading edge of the sheet in the sheet discharging direction comes into contact with the sheet discharge tray 8, and the subsequent sheet is nipped. When the sheet reaches the position, it is possible to reliably prevent the sheet from being jammed due to being pushed by the succeeding sheet at that portion and rubbing resistance at the front end in the discharge direction.

According to this embodiment, since the kicking section 14 is provided near the outer end of the driven roller 12, 12 'in the axial direction, the driven roller 12, 12' is positioned at both ends in the sheet width direction. Therefore, the trace of the kicking section 14 when riding on the kicking section 14 can be made less conspicuous as compared with a case in which traces are generated at portions other than both ends in the sheet width direction. In order to prevent both ends in the width direction from remaining at the holding position at the rear end of the sheet in the discharging direction, the kicking section 14 needs to be provided at least for the roller pair at both ends in the width direction.

Next, still another example according to the embodiment of the present invention will be described.

Driving roller 1 used in the above embodiment
1 the elastic body such as rubber is used, the driven roller 12, 12 'is formed of a resin roller thereto.

Since the present embodiment has the above configuration,
Utilizing the coefficient of friction of the driving roller 11 made of an elastic body, the sheet discharge is promoted.
The sheet can be prevented from being slippery by the materials 2 and 12 '. Since the sheet pulled by the driving roller 11 tends to slip on the peripheral surfaces of the driven rollers 12 and 12 ′, it is possible to prevent the peripheral surface of the driving roller 11 from being rubbed with the image and rubbing the image. can do.

According to this embodiment, the driven roller 1 is provided with a new function of kicking and pushing out the rear end of the sheet in addition to the original function of nipping and conveying the sheet.
Since the components 2 and 12 'are formed of resin molded products, they can be obtained as inexpensive components.

[0041]

According to the first and second aspects of the present invention,
The roller pair has different sheet discharge angles between the ends in the width direction of the sheet, and in particular, in the invention according to claim 2, if the opposing position of the other roller to one roller is different in the circumferential direction. Since the discharge angle of the sheet is made different by a simple configuration, the deformation state in the width direction of the sheet is made different, so that the bending rigidity, that is, the so-called waist strength can be made different. Accordingly, it is possible to set a stiffening strength at which no curl or the like occurs on the sheet in the tail width direction of the sheet to prevent the curl or the like from occurring on the sheet and secure a good stacking property.

According to the third aspect of the present invention, the discharge angle of the roller pair located in the sheet width direction of the roller pair is set to an angle that is more upward than the roller pair located between both ends in the sheet width direction. Therefore, a curved state in which both ends are directed upward along the width direction of the sheet is obtained. This allows
The resistance to curl in the sheet discharge direction is increased, so that the sheet does not curl at the stacking position. It is possible to prevent jam that occurs when the curl occurs and damage to the sheet due to the curl, thereby improving the stacking property. .

According to the fourth aspect of the present invention, since the pressing force on the roller pair located at the end in the width direction of the sheet is made larger than that on the roller pair between the ends,
It is possible to prevent the upward posture from being unable to be maintained due to a decrease in the pressing force at the width direction end of the sheet. As a result, it is possible to reliably prevent the sheet from being curled in the discharge direction while maintaining the curved state at the widthwise end of the sheet.

According to the fifth and sixth aspects of the present invention, among the driving and driven rollers in the roller pair, the roller located on the lower peripheral surface side of one of the rollers at a position deviated from the axial end. Since the kicking portion formed of the convex portion is provided on the outer peripheral surface, the rear end of the sheet can be pushed out near the widthwise end of the sheet. This allows the sheet to be punched to be ejected without interfering with the leading edge of the succeeding sheet, and furthermore, the sheet can be ejected toward the stacking position without any trace when the sheet is seated. Becomes

According to the seventh aspect of the present invention, one of the rollers in the roller pair corresponds to one of the rollers, and the driving roller which is in contact with the designated face drawing is formed of an elastic body, and the other roller corresponds to the lower peripheral surface of the driving roller. Since the driven rollers located opposite to each other are made of resin rollers, the frictional force at the time of nipping and conveying is favorably applied to the sheet, and the image is rubbed by the frictional force by the driven rollers. Can be prevented by making it slippery, and the stacking property can be improved without adversely affecting the image.

According to the eighth aspect of the present invention, since both ends can be curved upward in the width direction of the discharged sheet, the sheet to be discharged can be seated, and the curl at the leading end in the discharging direction can be curled. Loading can be prevented while preventing occurrence. As a result, it is possible to prevent the sheet stacking property from deteriorating, eliminate the work of aligning the edges, and simplify the image forming process.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a copying machine that is an example of an image forming apparatus using a paper ejection device according to an embodiment of the present invention.

FIG. 2 is a schematic diagram illustrating a main part for describing a configuration of a sheet discharging device used in the copying machine illustrated in FIG. 1;

FIG. 3 is a schematic diagram for explaining an arrangement relationship between a main roller shown in FIG. 2 and a driving roller driven roller.

FIG. 4 is a perspective view for explaining a configuration of a driven roller used for a main part shown in FIG. 2;

FIG. 5 is a front view of the driven roller shown in FIG. 4;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Copier as one of the image forming apparatuses 2 Photoconductor 7 Paper discharge device 11 Drive roller 12, 12 'Follower roller 13, 13' Leaf spring support 14 Kick-off part θ Ejection angle

Claims (8)

[Claims] 1. A sheet discharging device for nipping and conveying a sheet using a pair of rollers including a driving roller and a driven roller which can be interlocked with the driving roller in opposition to the driving roller, and discharges the sheet toward a predetermined position. A sheet discharging device, wherein a pair of rollers for nipping and conveying has a sheet discharging angle different between an end and a position between the ends in the width direction of the sheet. 2. The sheet discharging device according to claim 1, wherein the pair of rollers positioned at both ends in the width direction of the sheet and the pair of rollers positioned between both ends are arranged such that the position of the driven roller facing the driving roller is a circumference. A paper discharge device characterized by different directions. 3. The sheet discharging device according to claim 1, wherein the roller pair is provided at at least three places along a width direction of the sheet, and the width of the sheet is included in the roller pair. A sheet discharge device, wherein a discharge angle of the sheet at the roller pair located at both ends in the sheet width direction is set to be higher than a discharge angle of the roller pair located at both ends in the width direction of the sheet. 4. The sheet discharging device according to claim 1, wherein a pressing force on a roller pair at an end in the width direction of the sheet is larger than that of a roller pair located between the ends. A paper discharge device, which is set. 5. The sheet discharging device according to claim 1, wherein one of the driving roller and the driven roller constituting the roller pair is located on the lower peripheral surface side. A sheet discharging device, wherein a kicking portion is provided on an outer peripheral surface of the roller. 6. The paper discharging device according to claim 5, wherein a plurality of the kicking portions are provided along the circumferential direction outside the end face of the roller facing in the axial direction of the roller and are directed radially outward. A sheet discharging device comprising a projecting protrusion. 7. The sheet discharging device according to one of claims 1 to 6, one of the rollers in the roller pair is equivalent to the driving roller,
The other roller corresponds to a driven roller positioned opposite to the lower peripheral surface of the driving roller, the driving roller is configured by an elastic body that contacts the image surface of the sheet, and the driven roller is configured by a resin roller. A sheet discharging device. 8. An image forming apparatus using the sheet discharging device according to claim 1. Description: