JPH06115767A - Paper conveyer for image forming device - Google Patents

Abstract

PURPOSE:To convey paper while correcting it automatically to a normal position in the case of generating a diagonal feed or the like in the paper on the halfway of its feed by providing a function of correcting the diagonal feed in roller units of constituting a register roller unit. CONSTITUTION:A paper straightening device 5 arranged in a paper conveying path is constituted of feed roller units 6 and a register roller unit 10, to perform action of aligning paper. The register roller unit 10 is provided by opposing a drive roller 11, in which tapered roller members 13, 14 are provided in a drive shaft 12, to a pinch roller 15. The pinch roller is provided with a mechanism for pressing narrowed width roller members 17, 18 by both side springs. In the case of moving the roller member in an axial direction in a follow-up manner to the paper of generating a diagonal feed, a position of pressing against the tapered roller members of the two roller members is changed, and the paper is moved in a reverse direction to a direction of generating the diagonal feed and returned to a normal conveying condition.

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 an electrophotographic copying machine, which aligns a sheet immediately before a position where an image is formed on the sheet. The present invention relates to a sheet conveying device provided with a mechanism for automatically canceling the obliquely fed state when the sheet is obliquely fed after being processed.

[0002]

2. Description of the Related Art In an image forming apparatus such as an electrophotographic copying machine or a printer, a toner image is formed on an image bearing member such as a photoconductor drum by an electrophotographic method, and the toner formed on the photoconductor drum is formed. A mechanism for fixing the image transferred onto a sheet through a fixing device and discharging it as a copy is configured. Immediately before the image transfer section from the photoconductor drum, the paper is aligned and temporarily stopped, and the paper is sent toward the image transfer section in time with the toner image formed on the photoconductor drum. There is a paper alignment device for this.

As the sheet aligning device, for example, as disclosed in JP-A-2-231342, a registration roller device arranged immediately in front of an image transfer portion from a photosensitive drum, a gate member, and It is composed of a pre-registration roller device arranged at a predetermined interval on the upstream side of the roller device. In the paper aligning device, the leading end of the paper is locked to the gate member to form a loop on the paper, so that the leading end of the paper is aligned. Then, even when the sheet is obliquely fed while being fed from the paper feed tray or the like and being transported in the upstream portion of the sheet transport path, the sheet aligning device presses the leading edge of the sheet against the gate. By aligning with each other, the toner image transferred from the photosensitive drum can be accurately positioned.

[0004]

However, as described above, after the sheet aligning device imparts the aligning action to the sheet immediately before the image transfer portion of the photosensitive drum, the sheet is imaged by the registration roller device. When the sheet is conveyed toward the transfer portion, the sheet may have a stress in the twisting direction. Then, the sheet may be obliquely fed again while being conveyed by the registration roller device with the sheet having a stress in the twisting direction. Therefore, in order to prevent the above-described problems from occurring, for example, as shown in Japanese Patent Laid-Open No. 3-94275, when aligning the sheets, the leading end of the sheets is nipped by a registration roller device. In this state, it is also possible to use a means for moving the registration roller device in the width direction of the sheet conveyance path to set the alignment state of the sheet well.

However, as described above, when the means for moving the registration roller device in the width direction is used, there arises a problem that the driving mechanism for the registration roller device becomes complicated. Further, with respect to the sheet aligned by the sheet aligning device, if the stress in the twisting direction remains, after that, while the sheet is being sent out,
There is a problem that the sheet is obliquely fed. On the other hand, when the registration roller device is moved in the width direction to align the paper in the paper alignment device, the nip of the paper in the pre-registration roller device is released, and the stress in the twisting direction remains on the paper. Although it is possible to prevent such a problem, when such a means is used, there remains a problem that the device becomes complicated.

Further, in order to simplify the structure of the sheet aligning device and to eliminate the oblique feeding state that occurs in the sheet while the sheet is being fed out, for example, Japanese Patent Publication No. 61-
It is also conceivable to use a roller device as shown in Japanese Patent No. 60008. In the conventional paper transporting device, the roller device arranged at a predetermined position of the paper transporting path is configured such that the central roller has a large diameter and the diameters of the rollers are reduced toward both sides. Then, a pinch roller for pressing the paper is arranged. The operation of pressing the pinch roller is configured to be controllable to each drive roller, so that the state of oblique feeding of the sheet can be easily eliminated.

However, as described above, when a roller having a large diameter in the central portion and a roller having a small diameter on both sides is used with respect to the sheet conveying path, the structure of the roller device becomes complicated. This also causes an increase in the manufacturing cost of the paper aligning device. In addition, if the action of pressing the sheet against the drive roller can be changed according to the state of the oblique feeding of the sheet, there is a problem that the configuration of the controller of the sheet aligning apparatus becomes complicated, etc. In addition, there remains a problem that it is not possible to easily eliminate the skewed feeding state of the paper.

[0008]

SUMMARY OF THE INVENTION The present invention solves the problems of the conventional apparatus as described above. When the sheet aligned by the sheet aligning apparatus is again skewed, the skewed state is automatically adjusted. With the aim of providing a device that can be solved,
Further, it is an object of the present invention to make the mechanism for eliminating the diagonal feed simple.

[0009]

According to the present invention, a feed roller device is arranged upstream of a registration roller device,
The present invention relates to a device for performing an additional feeding action by a feed roller device in a state where the leading end of a sheet is thrust into a nip position of a registration roller device and forming a loop between the rollers to perform an aligning action. In the present invention, the registration roller device comprises a drive roller having two taper roller members mounted on a drive shaft at predetermined intervals, and a pinch roller pressed against the taper roller member of the drive roller. The taper roller member provided in
The roller member of the pinch roller pressed by the taper roller member is arranged with respect to the driven shaft by arranging the small diameter portion on the center side of the paper transport path and the large diameter portion on the side of the paper transport path. In addition to being slidable in the direction, a mechanism for restricting the movement with respect to the axis by springs arranged on both sides of the roller member is provided, and the roller member is moved by the stress of the oblique feed acting on the paper, and the paper is obliquely fed. It constitutes the means to eliminate.

As described above, when the taper roller member attached to the drive shaft and the pinch roller member movable in the axial direction are combined to form the registration roller device, the sheet is obliquely fed. However, the pressing force of the roller member with respect to the taper roller member is changed by the diagonal moving force of the paper, and the oblique feeding of the paper can be automatically canceled. Further, in the sheet aligning apparatus of the present invention, it is not necessary to provide a means for detecting the sheet conveyance state, and the structure of the sheet aligning apparatus can be simplified. Then, by the registration roller device, even if the sheet is obliquely fed while being fed toward the image transfer portion, it is possible to easily eliminate the inconvenient state.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A sheet conveying device of an image forming apparatus of the present invention will be described with reference to the illustrated example. The examples shown in FIGS. 1 and 2 show a configuration of an image transfer portion by discharge from the transfer corotron 2 with respect to the photosensitive drum 1, and a sheet aligning device 5 arranged immediately in front of the image transfer portion. There is. In the sheet aligning device 5 of the present invention, the feed roller device 6 and the registration roller device 10 are arranged with a predetermined interval,
Upper and lower rollers 13 that constitute the registration roller device 10,
The leading end portion of the paper is projected into the nip portion between 14 and 17, 18 and the feeding roller device 6 imparts an additional feeding action to form a loop on the paper P to align the paper. . The feed roller device 6 has a mechanism in which a driving roller 7 and a pinch roller 8 are arranged to face each other, and a sheet is nipped between both rollers so as to provide a conveying action, like a general conveying roller device. is doing.

As the registration roller device 10 arranged downstream of the feed roller device 6, a drive roller 11 and a pinch roller 15 are arranged so as to face each other. The drive roller 11 is arranged with respect to the drive shaft 12. The two taper roller members 13 and 14 are attached at a predetermined interval. The taper roller members 13 and 14
As shown in the figure, they are arranged in a state in which the large-diameter portion is located outside the paper transport path and the small-diameter portion is located on the central portion side of the paper transport path. Then, the drive roller 11 is driven via the drive shaft 12, and the pinch roller is pressed against the drive roller, so that the sheet nipped between the two roller members is conveyed.

The pinch roller 15 for pressing the paper against the taper roller member of the drive roller is a shaft 16
The roller members 17 and 18 are provided so as to be movable in the axial direction with respect to the shaft 16. In order to support the roller members 17 and 18 so as to be movable in the axial direction, in the pinch roller of the present invention, as shown in FIG.
Springs 20, 20a and 21, 21a are arranged on both sides of the springs, and spring stoppers 22, 22a and 23, 23 are arranged on both sides of each spring.
a is arranged respectively.

In the example shown in FIG. 3, in order to allow the pressing roller members 17 and 18 to move along the shaft 16, for example, as shown in FIGS. A roller core member 16a is arranged to face the roller core member 16a, and a main body 17 that constitutes a roller with respect to the roller core member 16a,
A mechanism for rotatably supporting each 18 can be provided. The roller core member 16a may be provided with an elongated hole 16b in the vertical direction at the center thereof to form a mechanism for guiding a square slider provided on the shaft. The pressing roller members 17 and 18 are the taper roller 1
Even when the sheet moves in the axial direction along the lines 3 and 14, the pressing roller member can perform the action of pressing the sheet toward the taper roller.

As a method of supporting the pressing roller member with respect to the driven shaft 16, the roller member 17,
It is also possible to provide a mechanism in which a large-diameter hole is provided on the center side of 18 so that the roller can freely rotate with respect to the shaft. On the other hand, in order to exert the action of accurately pressing the pressing roller members 17 and 18 toward the taper roller, a roller supporting mechanism as shown in FIG. Will be possible. Furthermore, in order to support the roller device of the present invention, any other supporting means can be used.

Then, the two roller members 17, 18
On the other hand, springs 20 and 21 are arranged respectively. Also, the spring has stoppers 22 on both sides,
The movement range in the axial direction is regulated by 23, and the movement of the roller member is allowed between the two springs. Then, when the lateral movement force is not applied by the paper, the roller member can be allowed to move in the axial direction within the width range of the corresponding tapered roller members 13 and 14.
The paper is pressed against the surface of the taper roller. As described above, the pinch roller member is arranged in the axial direction within the width of the taper roller member, the roller member is pressed against the taper roller member, and the paper is nipped between the two rollers to convey the paper. Action and
The effect of eliminating the oblique feeding can be performed.

In the sheet aligning apparatus of the present invention configured as described above, after performing the sheet aligning operation, the registration roller device 10 is driven to direct the sheet toward the image transfer portion from the photosensitive drum. Performs an operation to send at a constant speed. When the sheet is obliquely fed while being fed by the registration roller device, as shown in FIG. 5, the roller member 17 of the pinch roller follows the movement of the sheet in the width direction. , 18 move in the width direction of the paper transport path. As the roller member moves in the width direction of the sheet conveying path, the position where the roller member presses the sheet against the taper roller member changes.

That is, in the state where the sheet is conveyed straight in the sheet conveying path, the position where the roller member is pressed against the taper roller member is set to a fixed position, and the sheet is conveyed between the two roller devices. The speed at which you do it does not change. On the other hand, when the sheet conveyed by the registration roller device is in a state of being obliquely fed for some reason, for example, as shown in FIG.
When the sheet moves diagonally to the right side of the drawing, the roller member moves to the right side of the sheet conveying path following the diagonal movement of the sheet. Then, the position where the roller member presses the paper against the taper roller member is changed by the distance L from the central portion, and the conveyance speed of the two roller devices for the paper is changed.

When the roller member is moved to the right side in the state shown in FIG. 5, the diameter of the taper roller member that nips the paper is increased in the roller device on the right side of the paper carrying path, so that the paper carrying speed is increased. . On the contrary,
In the roller device on the left side of the paper conveyance path, the diameter of the portion where the taper roller member contacts the paper becomes small, so the paper conveyance speed becomes small. Therefore, due to the imbalance of the sheet conveying speed between the roller devices on both sides, a force acts to move the sheet to the left side of the sheet conveying path. And
In the state shown in FIG. 5, the sheet is obliquely fed to the right side of the sheet conveyance path, and two roller members that move following the sheet are positioned at the center of the opposing tapered roller members. Since the rollers are fed at the same speed, the paper can be fed straight as it is.

Further, when the sheet is biased to the side opposite to that shown in FIG. 5, an action opposite to the sheet correcting operation is given. That is, in the case where the sheet is obliquely fed toward the left side of FIG. 5 in the sheet conveying path, the roller members 17 and 18 that press the sheet toward the taper roller member are not the left taper roller member. The sheet is pressed against the large diameter portion, and the right taper roller member is pressed against the small diameter portion. Then, due to the difference in the conveyance speed between the taper roller members on both sides of the paper, the action of obliquely feeding the paper toward the right side of the paper conveyance path is generated, and the paper is conveyed while being corrected toward the central portion of the paper conveyance path. The status to be set is set.

As described above, when the two taper roller members are attached to the drive shaft and the roller members for pressing the paper against the taper roller members are arranged,
The taper formed on the taper roller member can be formed to have a relatively small inclination angle and the like. For example, in a general image forming apparatus, the state of oblique feeding of the paper in the paper conveying path appears very small, but the paper is several mm between the registration roller device and the image transfer section. Even if it is moved in the width direction, the quality of the copy becomes a problem. Therefore, in the paper transporting apparatus of the present invention, it is possible to correct the above-described state of minute feeding of the minute paper in the width direction by using the taper roller member.

Further, the sheet aligning means of the present invention configured as described above is not applied to the sheet aligning device, and in addition, while the sheet is being transported in the sheet transport path, It is also possible to arrange the sheet at a position where skew feeding is likely to occur. When arranging the sheet alignment mechanism in the middle of the sheet conveying path, the sheet is obliquely fed due to the positional relationship of the roller device of the sheet conveying device and the local wear of the roller member. Even in the case of the jam, it is possible to prevent the paper from coming into contact with a member on the side of the paper transport path and causing a jam. Further, even when the sheet is handed over to another device, the sheet can be sent out for the next operation while eliminating the obliquely fed state of the sheet by the aligning means.

[0023]

Since the sheet conveying device of the image forming apparatus of the present invention is constructed as described above, it has a driving roller having a taper roller member on its driving shaft and a pinch roller member movable in the axial direction. By configuring the registration roller device by combining the above, even when the sheet is obliquely fed, the pressing force of the roller member with respect to the taper roller member is changed by the moving force of the sheet in the oblique direction, Oblique feed can be automatically canceled. Further, in the sheet aligning apparatus of the present invention, it is not necessary to provide a means for detecting the sheet conveyance state, and the structure of the sheet aligning apparatus can be simplified. Then, even if the sheet is obliquely fed while being fed toward the image transfer portion by the registration roller device,
It is possible to easily eliminate the inconvenient state.

[Brief description of drawings]

FIG. 1 is a plan view showing a configuration of a sheet aligning device of the present invention.

FIG. 2 is a side view of the sheet aligning device of the present invention.

FIG. 3 is an explanatory diagram showing an arrangement relationship of roller members of a registration roller device and a configuration of a pressing roller member.

FIG. 4 is a side view showing a configuration of a pressing roller member.

FIG. 5 is an explanatory diagram of a state in which a sheet is obliquely fed.

[Explanation of symbols]

1 photoconductor drum, 5 paper alignment device, 6
Feed roller device, 10 Registration roller device, 11
Drive roller, 12 drive shaft, 13/14 taper roller member, 15 pinch roller, 17/18
Roller member, 20 ・ 21 spring, 22 ・
23 Spring stopper.

Claims (1)

[Claims] 1. A feed roller device is arranged upstream of a registration roller device, and an additional feeding action is given by the feed roller device in a state where the leading end of the paper is projected into the nip position of the registration roller device. In a device for forming a loop on a sheet between rollers to perform an aligning action, the registration roller device is provided with respect to a drive roller in which two taper roller members are attached to a drive shaft at predetermined intervals, and a taper roller member of the drive roller. And a pinch roller that is pressed by the taper roller member provided in the drive roller, the small diameter portion is arranged on the central portion side of the sheet conveying path, and the large diameter portion is arranged on the side portion side of the sheet conveying path. The roller member of the pinch roller which is pressed by the taper roller member is provided so as to be slidable in the axial direction with respect to the driven shaft, and is provided on both sides of the roller member. A sheet conveying device of an image forming apparatus, characterized in that a mechanism for restricting movement with respect to an axis is provided by a ring, and a roller member is moved by a stress of oblique feeding acting on a sheet to eliminate the oblique feeding of the sheet.