JPH08225196A - Paper adjusting device for image forming device - Google Patents

Abstract

PURPOSE: To transfer an image with avoiding an influence of stress on paper by providing a means releasing torsional stress generated in the paper when a loop is formed in the paper for performing adjustment between two roller devices arranged in a paper adjusting device. CONSTITUTION: A paper adjusting device consists of a register roller device arranged in a linear part in a photosensitive body drum and a preregister roller device arranged in the upstream part of the register roller device, and a driving shaft 22 is arranged in a driving roller member 21 in the preregister roller device movably in the axial direction, while a restricting member 30 is arranged in the shaft When a reaction force of torsional stress of the paper is applied to the driving roller member 21, the paper is conveyed out normally by moving the driving shaft 22. Then, the driving shaft 22 can be returned to the original position by means of plate spring members 32, 33 in the restricting member 30 when stress of the paper is eliminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet aligning device arranged immediately before an image transfer portion in an image forming apparatus such as an electrophotographic copying machine. The present invention relates to a sheet aligning device of an image forming apparatus that eliminates a stress such as a twist generated in a sheet when performing the sheet and enables the sheet to be delivered in a stable state.

[0002]

2. Description of the Related Art In an image forming apparatus such as an electrophotographic copying machine or a laser beam printer, a plurality of conveying roller devices are used for arranging a sheet sent from a sheet accommodating means such as a sheet feeding tray in a sheet conveying path. The toner image is transferred from an image bearing member such as a photosensitive drum. Then, the sheet on which the toner image has been transferred is fixed through a fixing device and discharged as a copy. In order to convey a sheet in the sheet conveying path, the conveying operation is performed while nipping the sheet by a large number of conveying roller devices, and all the roller members of the conveying roller device must exhibit uniform conveying force. However, it is inevitable that the paper will be inconveniently fed at an angle. Therefore, even if a sheet aligning device is arranged immediately before the position where the toner image is transferred from the photoconductor drum to the sheet, even if the sheet conveyed in the sheet conveying path is obliquely fed, the image transfer section does not It is possible to accurately set the position of the image with respect to the paper without causing the skew feeding state.

The sheet aligning device is constructed by arranging a registration roller device arranged close to the upstream portion of the photosensitive drum and a pre-registration roller device arranged further upstream with a predetermined gap. Mostly used. Then, with the leading edge of the paper protruding into the nip position of the registration roller device, the pre-registration roller device performs an extra feeding action to form a loop on the paper, and the leading edge of the paper is pulled by the reaction force of the loop of the paper. The aligning action can be given by uniformly entering the nip position of the registration roller device. However, as described above, if a loop is simply formed on the sheet and aligned, a twisted state occurs in the loop portion of the sheet, and after alignment, when the registration roller device is driven and the sheet is sent out. In addition, there are problems that the twisted portion of the paper is bent and wrinkled.

Therefore, in order to solve the above-mentioned problems, for example, as shown in Japanese Patent Application Laid-Open No. 2-18244, the twisting stress generated in the paper when the aligning action is applied is pre-registered. It has been proposed to eliminate this by moving the roller device in the axial direction. In the above-mentioned conventional example, the pinch roller member of the pre-registration roller device is supported on the shaft via a spring so that the roller member can be moved in the axial direction by the stress in the twisting direction generated on the paper. ing. Then, in the state where the sheet has finished passing, the roller member is returned to the original position by the reaction force of the spring so that the aligning and feeding action for the next sheet can be normally exerted.

Apart from the above-mentioned conventional example, JP-A-6-1498.
In the example disclosed in Japanese Unexamined Patent Publication (Kokai), a gate member is arranged immediately in front of the registration roller device to form a portion for locking the leading edge of the paper, and the pre-registration roller is provided upstream of the portion with a predetermined interval. Equipment is in place. Further, a sensor for detecting the side portion of the sheet is arranged on the side portion of the sheet aligning device to detect the oblique feeding state of the sheet, and the pinch roller member of the pre-registration roller device is detected by the detection information of the sensor. Is used to rotate the machine in the horizontal direction.
Then, by using the detection information of the side portion of the sheet by the sheet aligning device, the pinch roller member of the pre-registration roller device is rotated with respect to the vertical axis so as to perform the aligning action on the sheet. The sheet to be sent toward the sheet is accurately positioned with respect to the reference line of the sheet transport path, and it is possible to prevent misalignment of the position of the image transferred to the sheet.

[0006]

However, in the sheet aligning device as shown in the above-mentioned conventional example, when the pinch roller member is provided so as to be movable in the axial direction, the structure of the pre-registration roller device is simple. However, the reliability of the matching action remains a problem. In addition, in the device in which the pinch roller member of the pre-registration roller device is provided so as to be rotatable with respect to the vertical axis, the aligning action can be performed in a good state, but the device configuration becomes complicated, and a small image formation When incorporated in a device, there are many problems in the installation space and the manufacturing cost of the device.

In addition to the above-mentioned problems, when springs are arranged at both ends of the roller shaft and the roller shaft is provided so as to be movable in the width direction of the sheet, the neutral position of the roller by the spring is provided. The return action toward
As shown in the graph in FIG. In the graph shown in FIG. 18, the vertical axis indicates the return force F by the spring and the horizontal axis indicates the movement amount L of the roller. For example, the movement amount of the roller in the axial direction or the movement amount L of the roller shaft is If it is large, the returning force F acts with a large value. On the other hand, when the amount of movement of the roller is small, the return force F is very small. Therefore, when the stress on the paper is small, the roller is automatically set to the neutral position. In some cases, when the next sheet is aligned by the roller device in such a state, extra stress may be applied to the sheet.

In addition to the conventional examples described above, in a sheet aligning device, as shown in, for example, Japanese Patent Laid-Open No. 124752/1993, for each roller member of a registration roller device and a pre-registration roller device, It has also been proposed to arrange a mechanism for axial movement. In addition, in the above-mentioned conventional example, the leading end portion of the paper is aligned, and the paper can be sent toward the image transfer portion in a state where the paper is accurately aligned with the reference line. However,
The sheet aligning device using a complicated mechanism as in the conventional example is applied to a special image forming apparatus such as a color copying machine which is required to strictly deal with image misalignment. However, there remains a problem that it cannot be easily applied to a device such as a small printer.

[0009]

SUMMARY OF THE INVENTION The present invention solves the problems of the conventional sheet aligning apparatus as described above, simplifies the configuration of the aligning mechanism, and can be easily incorporated into a small image forming apparatus. It is an object of the present invention to provide a paper aligning device which can be manufactured and has high reliability.

[0010]

SUMMARY OF THE INVENTION According to the present invention, with respect to the paper fed from the paper feed tray, the leading end of the paper is thrust into the nip position of the registration roller device, and the pre-registration roller device feeds the paper excessively. The present invention relates to a sheet aligning device that forms a loop by adding a sheet to align the sheet, and then sends the sheet to the image transfer portion from the photosensitive drum. In the present invention, the pre-registration roller device is provided with means for releasing the twisting stress applied to the sheets at the time of aligning the sheets.
Further, in the present invention, the means for releasing the twisting stress of the sheet provided in the pre-registration roller device is constituted by a mechanism for sliding the roller member in the axial direction, or a mechanism for sliding the roller member in the axial direction. It is also possible to provide a driving roller member and a pinch roller member of the pre-registration roller device so as to be movable in the axial direction, respectively, and to provide means for holding the pre-registration roller device at the neutral position.

Further, in the present invention, means for supporting the roller shaft of the pre-registration roller device by a thrust bearing member made of a plastic material and fixing the thrust bearing member to the frame by using a claw member is provided. It can also be used. In addition to the above configuration, in the present invention, the means for releasing the twisting stress of the sheet provided in the pre-registration roller device may be configured using a mechanism for releasing the nip of the roller device.

[0012]

In the sheet aligning apparatus of the present invention, the pre-registration roller device is provided with means for releasing the twisting stress generated in the sheet, and the aligned sheet is sent out by the registration roller device and conveyed toward the image transfer portion. When doing this, make sure that the influence of the twisting stress of the paper does not occur. Also,
As the means for releasing the twisting stress, when the roller member is provided so as to be movable in the axial direction, the roller member of the pre-registration roller device is moved in the axial direction by the twisting stress generated on the sheet when performing the aligning action. be able to. Further, by constructing means for axially moving the pinch roller member or the driving roller member of the pre-registration roller device, or all of the opposing roller members, a mechanism for releasing the twist stress generated in the sheet at the time of alignment is provided. It becomes possible to configure.

In addition to the above structure, in the present invention, a thrust bearing made of a plastic material can be used as a bearing member for supporting the roller shaft, and a pawl member provided at the tip of the bearing member, Means for fixing and holding the large diameter portion on both sides of the frame can be provided. When the thrust bearing made of a plastic material as described above is used, it can be easily attached to the frame and the like, and the operation of moving the shaft in the thrust direction while rotating the shaft can be performed by a small friction force. be able to. Further, in the present invention, the pinch roller member of the pre-registration roller device is configured to be capable of being brought into contact with and separated from the driving roller member, and the position of the paper between the two roller devices arranged in the paper alignment device is confirmed. Then, by temporarily releasing the nip in the pre-registration roller device, it is possible to configure a mechanism for releasing the stress of the twisting stress generated in the paper.
Therefore, in the present invention, the structure of the mechanism for relieving the stress on the paper can be simplified, and the paper aligning device can be easily incorporated into a small image forming apparatus.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A sheet aligning device of an image forming apparatus of the present invention will be described with reference to the illustrated example. The image forming apparatus 1 shown in FIG. 1 is configured as a laser beam printer, and has a plurality of paper feed trays 2 and 2 at the bottom of the apparatus main body.
A is arranged, and the sheet feeding devices 3 and 3a arranged for the respective sheet feeding trays are used to configure a device for feeding the sheet. Further, an image writing device 12, a transfer member 11, a developing device 13, a cleaning device 14 and the like are arranged on the photoconductor drum 10 on the upper part of the apparatus main body to form a toner image using an electrophotographic method, It constitutes a device for transferring the toner image onto the paper. A sheet aligning device 4 is arranged between a sheet feeding device for the sheet feeding tray and an image transfer portion from the photosensitive drum. The sheet aligning device 4 includes a registration roller device 6 and a pre-registration roller device 5. It is provided to form a device for forming a loop on the sheet and aligning the sheet between the two roller devices.

In the image forming apparatus 1 configured as described above, the sheet feeding device 3 is provided in parallel with the operation of forming the toner image by irradiating the photoconductor drum 10 with the laser beam from the image writing device 12. To feed the paper from the paper feed tray. Then, with the leading edge of the sheet thrust into the nip position of the registration roller device 6, an extra feeding action is given by the pre-registration roller device 5 to form a loop on the sheet to make the leading edge of the sheet uniform. The registration roller device is pushed into the nip position to perform the aligning action on the paper. Then, in synchronization with the position of the toner image formed on the photosensitive drum, the registration roller device is driven to feed the sheet, and the toner image is transferred to the sheet by discharging the transfer member 11. As described above, the sheet onto which the toner image has been transferred passes through the fixing device 15 arranged on the upper side to which the fixing action is given, and the discharge roller device 16 is provided.
It is discharged toward the discharge tray 17 via the.

In the sheet aligning device of the image forming apparatus shown in FIG. 1, means for supporting the driving roller member and the pinch roller member of the registration roller device 6 through the bearings with respect to the frame of the device is arranged. The roller member is provided so as not to move in the width direction of the paper. On the other hand, the drive roller member of the pre-registration roller device can be provided via a mechanism that allows the roller to move in the axial direction, as shown in FIG. In the drive roller member 21 of the pre-registration roller device shown in FIG. 2, the rollers 23 at predetermined intervals with respect to the drive shaft 22.
Are arranged in a skewered shape, and both sides of the drive shaft 22 are supported by bearings 27, 27a provided on the frames 26, 26a.

The bearings 27 and 27a are configured to allow the rotation of the shaft and the movement in the thrust direction, and when the force for moving the roller device in the axial direction is applied, the drive roller member 21 is provided. Allows movement while sliding on the bearing. A gear 24 is arranged at one end of the drive shaft 22 with respect to the drive roller member 21, and the gear 24 meshes with the drive gear 25 to drive the shaft 22. By configuring the drive gear 25 to have a wide width, the drive transmission operation by the drive gear can be continued even if the drive shaft 22 moves.

At the other end of the shaft 22, a restricting member 30 for returning the shaft to the neutral position is arranged. The restricting member 30 is a ring member 31 fixed to the shaft.
And a stud member 34 arranged on the frame 35 of the device,
And a leaf spring member 3 provided so as to sandwich the stud member
It is composed of 2, 33. The ring member 31 can be provided by mounting a C ring or the like in a groove received in the circumferential direction of the shaft, and the ring member is provided so as not to move in the axial direction. Further, the stud member 34 provided so as to project from the frame 35 is provided so as to project to a position close to the ring member. Further, the leaf spring members 32 and 33 arranged on both sides of the restricting member have the base portion of the frame 3
5, or it is fixed through a screw member or the like, the upper portion is formed into a bifurcated shape, the protrusions are arranged on both sides of the shaft, and the ring member 31 can be locked.

The regulating member 30 having the above-mentioned structure
When a stress in the twisting direction is applied to the aligned sheets and the reaction force of the stress of the twisting stress of the sheets is transmitted to the roller member, the drive shaft 2 passes through the roller 23.
The action of moving 2 in the axial direction is added. Then, the ring member 31 arranged on the regulating member 30 presses either one of the leaf spring members 32 and 33, and the drive shaft 2
2 moves in the axial direction, and is held at the position where the drive shaft has moved until the reaction force of the stress applied to the drive shaft from the paper disappears. That is, until the trailing edge of the sheet has finished passing the nip position of the pre-registration roller device, or during the passage of the sheet until the stress is naturally eliminated, the drive shaft is the leaf spring member of the regulating member. Keep pressing.

As described above, after the regulating member is arranged on the drive shaft 22 and the roller is moved by the stress of the sheet by the two leaf spring members provided on the regulating member,
When a structure that exerts a returning action toward the neutral position is provided, as shown in the graph of FIG.
The return action by 3 is added. In the graph shown in FIG. 3, the vertical axis represents the returning force F, and the horizontal axis represents the axial movement amount L.
The state where the movement starts from the point where 1 and F2 are exhibited. Therefore, in the apparatus of the present invention, even if the roller or the shaft is moved in the axial direction even a little, a sufficient force is applied. Therefore, when the registration roller device is moved in the axial direction by the paper, it corresponds to the moving direction. As a result, a stable restoring force of an appropriate size acts, and the action of returning the roller to the neutral position can be accurately exhibited.

When the reaction force applied to the pre-registration roller device by the sheet is released from the above-described state, the force that the ring member 31 is pressing against the one leaf spring member disappears. An attempt is made to return the ring member 31 to the original position by the reaction force of the leaf spring member. Therefore, the drive shaft is returned to the position where the ring member is held between the two leaf spring members 32, 33 by the action of returning the drive shaft in the axial direction by one of the leaf spring members to cope with the subsequent sheet aligning action. It is held in a neutral position where it can. In addition, the leaf spring members 32, 33 arranged on both sides of the ring member 31.
Is a member having elasticity of the same value, and forms a predetermined gap between both leaf spring members to form a mechanism that allows the drive shaft to be slightly moved in the axial direction.

Then, even when a force for moving the roller in the axial direction is applied while the paper is being conveyed,
When the force in the axial direction is small, even if the ring member provided on the shaft moves to one side, it is automatically returned to the neutral position between the leaf spring members on both sides so that the roller device is self-aligned. The mechanism can be configured. As described above, the self-centering mechanism of the present invention is a mechanism in which when the shaft moves, a force for returning to the original position is automatically applied, and when the leaf spring member is pushed by the movement of the shaft, The leaf spring member is deformed. However, the action of returning the shaft to the neutral position (home position position) can be performed as soon as the moving action of the roller due to the stress of the paper is canceled and the pressing force on the shaft disappears.

As the pinch roller member which is combined with the drive roller member as shown in FIG. 2 and allows the movement in the axial direction, for example, a member having a structure as shown in FIG. 4 is used and combined with the drive roller member 21. be able to.
In this embodiment, the shaft 41 of the pinch roller member 40 is supported by a support member such as a guide plate via bearings 45 and 46 that allow rotation and axial movement, and the roller of the drive roller member is supported. On the other hand, the rollers 42 of the pinch roller member are brought into contact with each other at a predetermined nip pressure by using the spring 47. Further, rollers 42 are arranged on the shaft 41 of the pinch roller member 40 so as to correspond to the rollers of the driving roller member, and the spring 4 is provided via side ring members 48 and 49 provided at both ends of the shaft 41.
3 and 44 are arranged. The springs 43 and 44
Are arranged between the frames 26 and 26a of the apparatus main body, respectively, and apply a pressing action from both sides to the shaft of the pinch roller member to form an automatic centering mechanism.

In the pre-registration roller device of the present invention, in addition to the example shown in FIG. 4, it is possible to provide a pinch roller member 40a as shown in FIG.
The shaft 41 is supported on a guide plate or the like via a bearing 45, and the shaft 41 is supported so as to be movable in the axial direction. Further, spring receiving members 50 and 51 are arranged at both ends of the shaft 41 via side ring members 48 and 49, and the spring 4 is provided between the spring receiving member and the frames 26 and 26a on both sides.
3 and 44 are arranged respectively. The spring receiving member 5
Nos. 0 and 51 are configured such that the shaft 41 is inserted into a large-diameter hole provided so as to penetrate through the central portion, and in a state where the side ring member is in contact with the end portion of the spring receiving member, It is configured to transmit the reaction force of the spring to the shaft.

As described above, the spring receiving members 50 and 51 provided at the ends of the shafts have ring-shaped protruding members 50a and 51, respectively.
a is arranged respectively, and the movement restricting members 52 and 53 are arranged on the frame so as to correspond to the projecting members. Also,
The movement restricting members 52 and 53 are provided with a pair of protrusions at predetermined intervals, and when the action of moving the shaft 41 in the thrust direction is applied, the spring receiving member protrudes from the movement restricting members. Allows movement within the interval of. further,
Side ring members 48, 49 arranged at both ends of the shaft,
It is possible to form an arbitrary gap between each of the spring receiving members 50 and 51. Then, in such a configuration, the side ring member abuts the spring receiving member in a state where the pinch roller member moves by a certain width, and thereafter the shaft is moved while pressing the spring, After the side ring member is engaged with the spring receiving member, the movement range of the shaft can be stopped within the gap of the movement restricting member, and after the movement of the shaft by the sheet is released, the roller device is released. So that it can be easily returned to its original position.

As shown in FIGS. 4 and 5, by arranging the pinch roller members 40 and 40a with respect to the driving roller member 21, the roller is moved in the axial direction by the reaction force generated in the sheet in the twisting direction. The mechanism can be configured. Then, for example, with respect to the one in which the drive roller member 21 is configured as shown in FIG. 2 and means for restricting the range of movement of the drive roller member in the axial direction is provided,
As shown in FIGS. 4 and 5, the pinch roller member is configured as a mechanism which is interlocked with the driving roller member and allows movement in the axial direction.

Therefore, in the pre-registration roller device having the above-described structure, the sheet is aligned to cause a stress in the twisting direction, and the reaction force of the stress causes the roller to move in the width direction of the sheet. Even when a moving force is applied, the roller device is moved to a position where the stress on the paper can be eliminated, and then the upper and lower roller devices are returned to the neutral position by the returning means arranged at the end of the roller shaft. You can

[0028]

[Embodiment 2] In the present invention, in addition to providing the drive shaft moving mechanism for the drive roller member as shown in FIG. 2, an aligning mechanism as shown in FIG. 6 can be used. . In FIG. 6, the drive shaft 2 of the drive roller member
2 is supported by a bearing 27a provided on the frame 26a in a state permitting rotation and axial movement, but the shaft can be freely moved without providing a spring for pressing the roller from the side. To support. A gear 24 for driving transmission is attached to the drive shaft, but in the present embodiment, when the cams 37 and 38 are arranged on both sides of the gear 24 and the shaft is set to the initial position, the gears shown in FIG. As described above, the state in which the cam is pressed from both sides of the gear is set.

Further, in this embodiment, when the aligning action is performed on the sheet, as shown in FIG. 7, a state is set in which the cams on both sides are not pushed against the gear. Then, when a force that moves the roller member in the axial direction acts due to the stress of the paper, the drive roller member is moved in the direction of the force to eliminate the stress of the paper. Further, after the paper has come out of the nip position of the pre-registration roller device, the cams 37 and 38 are driven so that the roller members are initialized in the state shown in FIG. When the drive roller member as shown in FIGS. 6 and 7 is allowed to move freely and a mechanism for initializing is provided, the pinch roller member has the structure shown in FIGS. It is possible to provide a self-centering mechanism as shown. Further, even with respect to the pinch roller member, even if a mechanism that allows free axial movement without providing a spring or the like is provided, the pinch roller member moves following the drive roller member.

In addition to the examples shown in FIGS. 6 and 7, the drive roller member of the present invention may be provided with an aligning mechanism as shown in FIG. In the example shown in FIG. 8, the integral drive roller 60 is configured by integrally attaching the rollers 62 ... To the shaft member 61 at a predetermined interval, and
Is provided with a hole 63 penetrating the center of the shaft. Further, a slit 64 is provided at an end portion of the shaft member 61 on the drive gear side so that a locking pin 65 provided on the drive shaft 22 is engaged with the rotation of the drive shaft 22 to the shaft member 61. do it,
The drive roller member is configured to rotate.
The drive shaft 22 is provided with bearings 27, 27a arranged on the frames 26, 26a on both sides through the through hole 63 of the shaft member 61.
And a gear 24 is arranged at one end of the drive shaft 22 to drive the drive shaft 22 to drive the drive shaft 22.
Of the rotation is transmitted to the shaft member 61 via the locking pin 65.

Further, both ends of the shaft member 61 and the bearing 2
The springs 66 and 67 are arranged between the springs 7 and 27a to configure a mechanism for positioning the shaft member 61 with respect to the drive shaft 22. Therefore, as shown in FIG. 9, when the driving roller member is combined with the pinch roller member 40 to form the pre-registration roller device 20, when the aligning action is performed, the stress due to the twisting stress generated in the paper causes the stress. The drive roller member of the pre-registration roller device is integrated with the drive shaft by the drive roller 60.
Move while sliding. Then, the pinch roller member is integrally moved in the axial direction so as to follow the movement of the integral drive roller, so that the stress of the sheet is eliminated. As described above, when the trailing edge of the sheet has finished passing through the nip position of the pre-registration roller device, the spring force is applied by the reaction force of pressing one spring during the movement of the integral drive roller. Exerts the action of moving in the direction opposite to the stress direction,
The pre-registration roller device is initialized.

Further, in addition to the example shown in FIG. 8, the driving roller member provided in the pre-registration roller device of the present invention includes:
It is also possible to provide a biasing means as shown in FIG. In the example shown in FIG. 10, the frames 26, 2 on both sides are
The drive roller member 55 is configured by supporting the drive shaft 56 so as to allow rotation and axial movement with respect to the bearings 59, 59a provided on the 6a. In addition, the bearing 59,
The springs 58, 58a are provided between the locking member 59a and a locking member (a member such as a C ring, not shown) provided on the drive shaft.
Are arranged to form an alignment mechanism for the drive shaft. Then, as shown in FIG. 10, even when the self-aligning mechanism for the drive roller member is provided, the pinch roller members are arranged so as to face each other to form the pre-registration roller device. It is possible to relieve stress and perform an aligning action without paper.

[0033]

[Third Embodiment] As described above, if a ball bearing is used as the bearing member for allowing the movement and rotation in the thrust direction with respect to the shaft, a good supporting action can be achieved. In the device of the present invention, FIG.
A bearing member 80 as shown in 12 can be used.
As the bearing member 80, one formed as an integrally molded member of plastic (POM resin, oil-impregnated POM resin, or the like) can be used. The insertion portion 82 configured as described above is arranged. The insertion portion 82 is configured by combining cylindrical portions 83 and 83a having an arcuate cross section and locking portions 84 and 84a, which are opposed to each other. Further, the locking portions 84 and 84a are integrally provided by projecting the claw members 85 and 85a outward from the tip end portions.

The bearing member 80 constructed as described above is
As shown in FIG. 13, the insertion portion is inserted into the shaft hole 36 provided in the frame 35 of the device, and the flange 81 and the claw member 8 are inserted.
5, 85a is used to lock and hold from both sides of the frame. Then, the shaft 2 is inserted into the shaft hole 86 of the bearing member 80.
By inserting and holding 2 in this way, a support member that allows rotation of the shaft and movement in the thrust direction is configured. In the bearing member having the above-mentioned configuration,
It has a structure that allows rotation of the shaft,
When it is intended to move the shaft only in the thrust direction, the frictional resistance is usually relatively large. However, in the bearing member of the present invention, since the shaft moves in the thrust direction while rotating, the operation of moving the roller member in the axial direction can be performed with a relatively small value of frictional resistance. Is.

The bearing members shown in FIGS. 11 to 13 can be applied to any of the bearing members shown in the embodiments of the present invention, and the operation of attaching and detaching the bearing member to and from the frame is facilitated. In addition to being able to perform, the shaft supporting action can be performed in a good state. Further, the bearing member can be configured by using any plastic material, and the shape of the tubular portion or the locking portion arranged in the insertion portion can be any shape. is there.

[0036]

Fourth Embodiment As described above, the pre-registration roller device arranged in the sheet aligning device is provided with the moving mechanism corresponding to the stress of the twisting stress generated in the sheet to align the sheet and eliminate the stress. In addition to this, in the present invention, the pre-registration roller device may be provided with a nip releasing means as shown in FIG. In the pre-registration roller device 20 shown in FIG. 14, the pinch roller member 40 is arranged so as to face the drive roller member 21 arranged at the fixed position, and the pressing member 74 is arranged against the pinch roller member 40. The spring 73 is arranged via the above so that a predetermined nip pressure can be set. The solenoid 7 is attached to the pinch roller member 40.
A link 71 that is swung by 0 is provided via a support shaft 72, and the tip of the link 71 is attached to the shaft 4 of the pinch roller member.
It is arranged on the nip side of 1. Then, by operating the solenoid 70 and swinging the link 71 in the clockwise direction via the support shaft 72, the pinch roller member 40 is separated from the drive roller member 21 and the sheet nip can be released. To

When the pre-registration roller device configured as shown in FIG. 14 is combined with the registration roller device to form a sheet aligning device, the action of aligning the sheets in the order shown in FIGS. And, the operation of relieving the stress of the paper can be performed. In the example shown in FIG. 15, when the sheet is conveyed and enters the nip position of the pre-registration roller device 5, the registration roller device 6 is held in a stopped state as shown in FIG. Then, the paper P is further conveyed by the pre-registration roller device, enters the nip position of the registration roller device 6 as shown in FIG.
As shown in (1), a loop Pr is formed on the paper P to align the paper.

As described above, the registration roller device 6 is driven to carry the sheet toward the image transfer portion after the sheet is aligned. Then, after the registration roller device 6 nips the leading end of the paper and starts the operation of conveying the paper, after a predetermined time has elapsed, the nip of the pre-registration roller device is released as shown in FIG. To perform the action. When the nip of the pre-registration roller device is released, the stress in the twisting direction that has occurred on the sheet is naturally eliminated by the reaction force of the sheet, and as shown in FIG. Will not occur. In addition, as described above, after the stress on the paper is released, the nip of the pre-registration roller device is restarted so that the paper is conveyed toward the image transfer unit by the two roller devices of the paper aligning device. You can also

The operation of the sheet aligning device shown in FIG. 15 can be performed as shown in the timing chart of FIG. In the timing chart shown in FIG. 16, the operations of A to E of FIG. 15 are shown in accordance with the driving of the roller device, etc., and the registration roller device 6 finishes the paper alignment operation, After the nip of the registration roller device is released, drive control is performed so as to carry out the conveyance action on the sheet. FIG. 15,
As shown in FIG. 16, when the alignment with respect to the sheet and the operation of sending out the sheet are performed, the operation of each roller device can be controlled as shown in the flowchart of FIG.

In the examples shown in FIGS. 15 and 16, after the registration roller device starts to convey the sheet, a predetermined time has passed (for example, the leading end of the sheet is securely nipped). It is possible to use a control method in which the operation of releasing the nip in the pre-registration roller device is performed. When the control method as described above is used, it is possible to surely release the stress generated on the sheet by the aligning action and the carrying action, and immediately after releasing the stress on the sheet, In the case where the pre-registration roller device performs the nip and the carrying action on the paper, the paper carrying action can be favorably performed.

In the flow chart shown in FIG. 17, when a copy start signal is input, the pre-registration roller device starts rotating in step a-1 to cope with the paper sent from the paper feed tray. . Then
When the sensor arranged corresponding to the sheet aligning device detects the sheet (step a-2), the timer value t is set in the control device in step a-3, and when the time t elapses in step a-4, step a Move to -5 and stop the pre-registration roller device. The time set as the timer value t is the time required for making the leading end of the sheet plunge into the nip position of the registration roller device, forming a loop with respect to the sheet, and aligning the sheets.

When the image recording signal for the photosensitive drum is input as shown in step a-6 while the sheet is held in the stopped state as in step a-5,
In step a-7, driving of the registration roller device is started. Immediately after that, in step a-8, the operation of releasing the nip of the pre-registration roller device is performed, and at the same time,
The timer is turned on, and after a predetermined time has passed, the timer is turned off (step a-9). The timer value set between the steps a-8 and a-9 is set to such an extent that the stress of the paper can be released in a very short time such as the time when the loop of the paper is not completely removed. ,
It is possible to perform the sheet conveying operation in the sheet aligning device in a good state. Then, in the state shown in step a-9,
When the sensor detects the trailing edge of the sheet as shown in step a-10 while the sheet is being sent out, the conveying action of the sheet aligning device for the sheet is completed, and the next sheet is conveyed in step a-11. If there is not, perform the end operation,
If there is a next sheet, the process proceeds to the sheet aligning device a-1 of the image forming apparatus and the sheet aligning and feeding operations are performed again.

[0043]

Since the sheet aligning device of the image forming apparatus of the present invention is configured as described above, the pre-registration roller device is provided with a means for releasing the twisting stress generated in the sheet to align the sheet. It is possible to prevent the influence of the twisting stress of the sheet from occurring when the formed sheet is sent out by the registration roller device and conveyed toward the image transfer portion. Further, when the roller member is provided so as to be movable in the axial direction as the twisting stress releasing means, the roller member of the pre-registration roller device is axially moved by the twisting stress generated in the sheet when performing the aligning action. It can be moved. Further, by constructing means for axially moving the pinch roller member or the driving roller member of the pre-registration roller device, or all of the opposing roller members, a mechanism for releasing the stress generated in the sheets at the time of alignment is configured. It is possible to do so.

In addition to the above effects, in the present invention, a thrust bearing made of a plastic material can be used as a bearing member for supporting the roller shaft, and a claw member provided at the tip of the bearing member, Means for fixing and holding the large diameter portion on both sides of the frame can be provided. When the thrust bearing made of a plastic material as described above is used, it can be easily attached to the frame and the like, and the operation of moving the shaft in the thrust direction while rotating the shaft can be performed by a small friction force. be able to. further,
According to the present invention, a mechanism that allows the pinch roller member of the pre-registration roller device to be brought into and out of contact with the drive roller member is used to check the position of the paper between the two roller devices arranged in the paper alignment device. By temporarily releasing the nip in the pre-registration roller device, it is possible to configure a mechanism for releasing the twisting stress generated in the paper. Therefore, in the present invention, the structure of the mechanism for relieving the stress on the sheet can be simplified, and the sheet aligning device can be easily incorporated into a small image forming apparatus.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a configuration of an image forming apparatus to which the present invention can be applied.

FIG. 2 is an explanatory diagram of an example in which a drive roller member of a pre-registration roller device is configured to be movable in an axial direction.

FIG. 3 is a graph showing a state of a moving amount and a returning force when a spring is arranged on a shaft of the roller device of the present invention.

FIG. 4 is an explanatory diagram of an example in which a pinch roller member is configured to be movable in the axial direction.

FIG. 5 is an explanatory diagram showing another example of the configuration of the pinch roller member.

FIG. 6 is an explanatory diagram of a device that blocks the movement of the drive roller member.

FIG. 7 is an explanatory diagram of a state in which the drive roller member is allowed to move.

FIG. 8 is an explanatory diagram of another example of the movement permitting mechanism of the drive roller member.

9 is an explanatory diagram of an example in which the drive roller member of FIG. 8 is combined with a pinch roller member.

FIG. 10 is an explanatory diagram of a third embodiment of a mechanism that allows the drive roller member to move in the axial direction.

FIG. 11 is a front view of a bearing member used in the present invention.

FIG. 12 is a side view of a bearing member.

FIG. 13 is an explanatory diagram showing a state where the bearing member of FIG. 11 is mounted on a frame.

FIG. 14 is an explanatory diagram showing a configuration of a nip releasing mechanism of the pre-registration roller device.

FIG. 15 is an explanatory diagram showing, step by step, the order of operations for forming a loop on a sheet.

16 is a timing chart corresponding to the operation of FIG.

17 is a flowchart showing the control sequence of the operation of FIG.

FIG. 18 is a graph showing a state of a moving amount and a returning force in a device in which a spring is arranged on a shaft of a conventional roller device.

[Explanation of symbols]

1 image forming apparatus, 2 paper feed tray, 5 pre-registration roller device, 6 registration roller device, 1
0 photoconductor drum, 20 pre-registration roller device, 21 drive roller member, 22 drive shaft, 2
3 rollers, 30 regulating member, 31 ring member, 32/33 leaf spring member, 40 pinch roller member, 55 drive roller member, 60 integrated drive roller, 70 solenoid, 80 bearing member, 82 insertion part, 84 locking part, 85 Claw member.

Claims (5)

[Claims] 1. A loop is formed for a sheet fed from a sheet feed tray, in which a leading end of the sheet is thrust into a nip position of a registration roller device and the pre-registration roller device feeds the sheet excessively. In a sheet aligning device for aligning and then sending the image from the photosensitive drum toward the image transfer portion, the pre-registration roller device is provided with means for releasing the twisting stress applied to the sheets at the time of aligning the images. Paper alignment device for forming machine. 2. The image forming apparatus according to claim 1, wherein the means for releasing the twisting stress of the sheet provided in the pre-registration roller device is constituted by a mechanism for sliding the roller member in the axial direction. Paper alignment device. 3. The pre-registration roller device is provided with a means for releasing a twisting stress of a sheet by a mechanism for sliding a roller member in an axial direction, and a drive roller member and a pinch roller member of the pre-registration roller device are provided. 3. The sheet aligning apparatus for an image forming apparatus according to claim 2, wherein each of the sheet aligning apparatuses is provided so as to be movable in the axial direction, and means for holding the pre-registration roller device in a neutral position is provided. 4. The roller shaft of the pre-registration roller device is supported by a thrust bearing member made of a plastic material, and the thrust bearing member is fixed to the frame by a claw member. 2. A sheet aligning device of the image forming apparatus according to item 2. 5. The image forming apparatus according to claim 1, wherein the means for releasing the twisting stress of the sheet provided in the pre-registration roller device is configured by using a mechanism for releasing the nip of the roller device. Paper alignment device.