JPH07267427A - Paper registering device for image forming device - Google Patents

Abstract

PURPOSE:To satisfactorily perform a feeding action by preventing a guide plate and the like from being brought into contact with the loop of a paper sheet with uneven pressure, and applying a uniform pressing action from the back face of the loop in a paper registering device forming the loop on the paper sheet between a register roller device and a pre-register roller device for the registering action. CONSTITUTION:Roller devices 2, 3 are arranged at a specific interval, and a loop is formed on a paper sheet between both roller devices 2, 3 in a paper registering device 1 arranged immediately before an image transfer section from the photoreceptor drum of an image forming device. A rocking paper guide member 10 is arranged in response to the protruding direction of the loop of the paper sheet, and the guide member 10 is made rockable via a support shaft 13 provided at the center in the width direction of the paper sheet. When the loop of the paper sheet is not uniform, the guide face 11 of the rocking paper guide member 10 presses the loop of the paper sheet with a uniform pressure.

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 is disposed immediately before a position where a toner image is transferred from an image bearing member such as a photosensitive drum onto a sheet, and a registration roller device. The present invention relates to a sheet aligning device that arranges pre-registration roller devices with a predetermined interval and forms a loop on the sheet between the rollers to perform an aligning action. In particular, a loop formed on the sheet is formed in the width direction of the sheet. The present invention relates to a sheet aligning device of an image forming apparatus in which a rocking sheet guide member is arranged in a state of being pressed from the back of the loop with a uniform pressure when the sheet is not uniform.

[0002]

2. Description of the Related Art A method of forming a toner image on an image bearing member such as a photoconductive drum by using an electrophotographic method and transferring the toner image onto a sheet, such as an electrophotographic copying machine or a laser beam printer, is used. In the image forming apparatus, the sheet aligning device is arranged immediately in front of the image transfer portion from the photosensitive drum. In the sheet aligning device arranged in the sheet conveying path of the image forming apparatus, a loop is formed on the sheet between the registration roller device and the pre-registration roller device as disclosed in, for example, Japanese Patent Laid-Open No. 60-100156. And a means for causing the leading end of the sheet to enter the nip position of the registration roller device in parallel by the reaction force of the loop.

In a paper aligning device arranged at the end of a paper conveying path of a general image forming apparatus, as shown in FIGS. 13 and 14, a registration roller device 2 is arranged in a position close to a photosensitive drum, A pre-registration roller device 3 is arranged upstream of the pre-registration roller device 3 at a predetermined interval. Then, with the leading end of the sheet P conveyed toward the sheet aligning device 1 protruding into the nip position of the registration roller device 2, the conveying action of the pre-registration roller device 3 is continued, whereby A loop Pr is formed, and the reaction force of the loop of the sheet causes the leading end of the sheet to uniformly project into the nip position of the registration roller device 2 and is stopped. After that, the registration roller device 2 is driven in synchronism with the position of the toner image formed on the photoconductor drum, and the paper is sent out from the photoconductor drum toward the image transfer portion. Try to transfer the image.

Therefore, by disposing the sheet aligning device as described above at the end of the sheet transport path, the sheet transported in the sheet transport path is transported by the transport roller device while the sheet transport path is being transported. Even if the sheet is obliquely fed with respect to the reference line, the sheet aligning device can correct the sheet curl. Then, it is possible to prevent the position of the image transferred on the sheet from being displaced and to improve the copy quality. Further, in the sheet aligning device as shown in FIG. 14, the guide plates 5 and 6 for guiding the sheet are arranged vertically, and one of the guide plates is largely curved according to the state of the loop formed on the sheet. The protrusion of the loop formed on the sheet does not contact the guide plate excessively.

[0005]

However, when the sheet aligning device as described above is arranged to perform the aligning action on the sheet, as shown in FIG. 13, the shape of the loop Pr formed on the sheet is constant. Is not formed in the state of
The leading side loop Pa is formed large on one side of the sheet, and the lag side loop Pb is formed small on the other side. Further, the sheet aligned by the sheet aligning device has a large loop on one side and a small loop extending to the other side, so that the shape of the loop is distorted. Further, the action of pressing the sheet against the nip portion of the registration roller device by the reaction force of the loop formed on the sheet is strong in the large leading side loop Pa and is weak in the small forming lag side loop Pb. Therefore, the action of strongly pushing the leading end of the sheet of the leading side loop Pa into the nip part of the registration roller device is added.
The action is weak in the delay side loop Pb. Therefore,
When the sheet aligned by the sheet aligning device is driven toward the image transfer portion of the photoconductor drum by driving the registration roller device, there is a disadvantage that the advance side loop Pa is advanced, so that it is transferred to the sheet. Problems such as the toner image being inclined are likely to occur.

Further, in the sheet aligning apparatus as described above, as shown in FIG. 14, the upper guide plate is curved upward so as to correspond to the protrusion of the large loop. However, when the paper is in a state of being largely fed at an angle, the leading side loop formed by the paper aligning device may come into contact with the upper guide plate 5 or press the upper guide plate 5. Then, when the leading side loop is formed large in a state of pressing the upper guide plate, the reaction force from the upper guide plate exerts an action of pushing out the leading end of the paper with respect to the loop of the paper. It
Since the action of pushing out the leading end of the sheet is weak in the delay side loop Pb, the problem that the aligning action with respect to the sheet is difficult to be performed occurs.

In order to solve the above-mentioned problems, for example, as disclosed in Japanese Patent Publication No. 2-43183, a sheet-like member for pressing and regulating the loop of the sheet is arranged. As disclosed in Japanese Patent Publication No. 63-8020 and the like, it has been proposed to provide a means for pressing against the loop. In addition to the loop restricting means, as shown in Japanese Utility Model Laid-Open No. 59-8936, there is provided a means for blowing air against the paper and pressing the paper toward the registration roller device. Is also considered. However, the use of the loop restricting means as described above exerts an action of strongly pressing the large formed loop toward the registration roller device, so that the leading end of the advance side loop is registered. The problem that the action of pressing toward the nip portion of the roller device is added remains.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to solve the problem of the sheet aligning action in the sheet aligning apparatus as described above, and to use a swingable paper guide member which swings in correspondence with a loop formed on the sheet as a guide plate. By arranging in a corresponding manner and applying a uniform pressing action from the back of the loop formed on the paper,
An object of the present invention is to provide a sheet aligning device of an image forming apparatus in which the leading end of the sheet can be projected in parallel with the registration roller device.

[0009]

SUMMARY OF THE INVENTION The present invention is a sheet aligning device arranged upstream of an image transfer unit from an image carrier of an image forming apparatus, wherein the sheet aligning device is located near the image carrier. And a pre-registration roller device disposed upstream of the registration roller device and forming a loop between the rollers to form a loop between the rollers to perform a sheet positioning operation. . In the present invention, a rocking paper guide member is arranged corresponding to one of the guide plates arranged between the registration roller device and the pre-registration roller device, and the rocking paper guide member is arranged in a loop of paper. A corresponding guide surface is provided and is supported by a support shaft arranged in a direction perpendicular to the roller axis of the registration roller device,
The support shaft is provided so as to be swingable in the width direction of the paper, and is swung around the support shaft according to the shape of the loop of the paper. It constitutes a pressing means.

Further, in the present invention, the rocking paper guide member may be provided with a means for preventing the tilting paper guide member from tilting via the support shaft in the absence of paper. Further, in the present invention, a support shaft for supporting the rocking paper guide member is arranged at a central portion in the width direction of the paper transport path, and the rocking paper guide member is provided around the support shaft in the paper width direction. It is also possible to configure a means for swinging to. In addition to the above-mentioned configuration, in the present invention, a supporting means is provided by a horizontal axis parallel to the axis of the roller of the registration roller device with respect to the support shaft that supports the rocking paper guide member, and the rocking paper guide member is provided. It is also possible to swingably support two orthogonal axes. Further, in the present invention, means for supporting the rocking paper guide member by two orthogonal support shafts is provided, and the guide surface of the rocking paper guide member against the rocking action of the registration roller device with respect to the axis of the roller. It is also possible to arrange biasing means for pressing the loop of paper from behind.

In addition to configuring the sheet aligning device of the image forming apparatus as described above, in the present invention, the sheet aligning device is arranged at a position for conveying the sheet in the vertical direction, and the sheet aligning device is arranged in two opposite directions. The present invention is also applicable to a case where a unit for feeding a sheet toward the sheet aligning device and providing an aligning action to the sheet conveyed from each direction is configured. Further, a vertical guide member having two vertical guide surfaces is provided for the paper aligning device, and the vertical guide member is supported by the vertical guide member so as to be swingable in the width direction of the paper via the vertical axis. Means can be provided. Also, 2
In a device that feeds a sheet from two facing sides toward a sheet aligning device, two vertical axes are arranged with respect to a vertical guide member so as to correspond to the center position of the sheet fed from the facing side. Accordingly, the vertical guide member may be configured to swing via one vertical axis.

[0012]

As described above, according to the present invention, the rocking paper guide member is arranged with a part of the guide plate in the paper aligning device cut out so as to adjust the size of the loop formed on the paper. The oscillating paper guide member is oscillated so that the guide surface provided on the oscillating paper guide member applies a pressing action from behind the loop of the paper. Even if the loop shape of the sheet is not formed in the width direction of the sheet, the guide surface of the rocking sheet guide member can press the protrusion of the loop of the sheet in accordance with the loop shape. Therefore, it is possible to uniformly apply a force for pushing the paper toward the nip portion of the registration roller device in the width direction of the paper. Therefore, after being aligned by the sheet aligning device of the present invention, the sheet delivered toward the image transfer portion is given a uniform pressing action in the width direction without being affected by the size of the loop formed on the sheet. Therefore, it is possible to accurately set the transfer position of the image on the sheet fed by the registration roller device.

Further, in the present invention, the sheet aligning device may be constructed in the vertical direction so as to correspond to the device for feeding the sheets from the sheet accommodating means such as the sheet feeding trays arranged on both sides. Then, with respect to the vertical guide member arranged in the vertical paper aligning device, two guide surfaces are arranged corresponding to the paper feeding devices on both sides, and the vertical guide member is vertically arranged corresponding to the loop formed on the paper. By oscillating along the axis, it is possible to perform the feeding action of the sheets after the alignment of the sheets in a good state. Further, in addition to constituting a means for supporting the vertical guide member by one shaft, when the size of the paper fed from two directions is different, the vertical guide member is supported by the two shafts. It is also possible to configure a mechanism for supporting the member and swinging the vertical guide member by using an arbitrary shaft corresponding to the size of the paper.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A sheet aligning device of an image forming apparatus of the present invention will be described according to the illustrated embodiments. In the example shown in FIGS. 1 and 2, the sheet aligning device 1 is similar to the conventional device, and is a registration roller device 2 arranged close to a downstream portion of a device such as a photosensitive drum, and the registration roller device 2 described above. On the other hand, the pre-registration roller device 3 which is arranged on the upstream side with a predetermined space therebetween is combined.
Further, an upper guide plate 5 and a lower guide plate 6 for restricting the upper and lower positions of the paper are arranged between the roller devices before and after the paper aligning device 1, and the upper guide plate 5 is formed on the paper. It is provided in a state in which it is bent to the upper side in correspondence with the loop to be turned. Further, a rocking paper guide member 10 is arranged between the upstream end portion of the upper guide plate 5 and the pre-registration roller device 3, and the rocking paper guide member 10 is arranged.
Is a direction perpendicular to the axis of the rollers of the registration roller device, with respect to the line connecting the nip portions of the two roller devices,
It is supported via a support shaft 13 which is arranged so as to be inclined by an angle θ.

As shown in FIG. 3, the oscillating paper guide member 10 arranged in the paper aligning device 1 is made to correspond to the paper P having a loop formed by inserting the leading end into the nip position of the registration roller device 2. Then, the rocking paper guide member 10 is rocked in the width direction of the paper through the support shaft 13 in accordance with the shapes of the leading side loop Pa and the lagging side loop Pb. Further, the guide surface 11 of the rocking paper guide member 10 is configured as a curved surface similar to the shape of a loop formed on a general paper, and the guide surface of the guide member is formed according to the shape of the loop formed on the paper. Is automatically positioned so that a uniform pressing action can be applied from the back of the loop in the width direction of the paper. In the illustrated example, the shaft support 12 is provided behind the body of the rocking paper guide member 10.
It is possible to use means for disposing the support shaft 13 so as to rotatably support the support shaft 13 with respect to the shaft support 12. Therefore, in the example shown in FIG. 3, the support shaft 13 is fixedly attached to the means for supporting the support shaft, and the rotation shaft is provided to the support shaft 13 through the means for allowing rotation. Thus, the swinging paper guide member main body can be supported rotatably around the axis.

In the present invention, the rocking paper guide member 10 arranged in the paper aligning device can be constructed as shown in FIG. 4, and the rocking paper guide member is formed into a substantially wedge shape by using a plastic material. The guide surface 11 is integrally formed to have a substantially arc shape, and the support shaft 13 is arranged at the rear portion facing the sheet conveying direction. Between the projecting direction of the support shaft 13 and the tangent line of the guide surface 11, it is configured to be inclined by an angle θ, and the main body of the rocking paper guide member 10 is rocked around the axis of the support shaft 13. This makes it possible to cope with a paper loop. Further, in the swinging paper guide member of the present invention, as shown in FIG. 5, springs 16 and 16a are respectively arranged on the back surface corresponding to the guide surface 11 of the swinging paper guide member main body, and the support shaft 13 is provided. It is possible to provide a means for restricting the swing of the guide surface 11 when swinging the swing paper guide member in the direction of the arrow via. The spring arranged on the back surface of the rocking paper guide member is a rocking paper guide member 10.
When the sheet is not pressed by the sheet, the swing sheet guide member can be prevented from unnecessarily swinging or vibrating via the support shaft.

In addition to the supporting means for the rocking paper guide member of the present invention, the supporting means for the rocking paper guide member 10 as shown in FIG. 6 can be constructed in the present invention. In the example shown in FIG. 6, the support shaft 1 is attached to the main body of the rocking paper guide member 10 via the shaft support 12.
3 constitutes a supporting means, and further constitutes a swinging mechanism using a horizontal shaft 15 with respect to the support shaft 13. In the example shown in FIG. 6, the base portion of the support shaft 13 is supported by the bracket member 14, and the bracket member 14 is swingably supported with respect to the horizontal shaft 15. Therefore,
The oscillating paper guide member 10 supported by the two orthogonal shaft members 13 and 15 can be oscillated in correspondence with the length direction and the width direction of the paper, and has a loop shape formed on the paper. It is possible to set a state in which the guide surface of the oscillating sheet guide member is uniformly pressed, and to perform an action of pressing the aligned sheet in the feeding direction in a good state. Further, the spring 1 arranged behind the swinging paper guide member 10
Numeral 7 assists the positioning operation with respect to the oscillating paper guide member, and can prevent the oscillating paper guide member from excessively vibrating.

Further, the supporting means for the swinging paper guide member of the present invention may be configured as shown in FIG. In the oscillating paper guide member 20 shown in FIG. 7, the main body of the oscillating paper guide member 20 is made of a plate member made of a plastic material and having an arcuate cross section, and a plurality of members are provided behind the oscillating paper guide member. Bracket 21
23 are projected. A round hole 25 is formed in the central bracket 22 provided behind the rocking paper guide member, and long holes 24, 24a are inclined in the same direction for the brackets 21, 23 on both sides. Thus, the support shaft 26 is arranged with respect to the hole. Therefore, in the oscillating paper guide member 20 shown in FIG. 7, the position where the shaft supports the bracket 22 arranged in the central portion behind the oscillating paper guide member in the state where the guide surface is pressed by the paper loop. It is possible to allow the rocking of the rocking paper guide member in a state in which the brackets supported by the long holes on both sides move around the.

Further, in the swinging paper guide member of the present invention,
In addition to supporting the rocking paper guide member by one support shaft as shown in each of the above-mentioned embodiments, as shown in FIG. It is also possible to arrange support means by means of a support shaft. In the example shown in FIG. 8, a supporting member 7 is provided on the upper guide plate 5 of the sheet aligning device 1, and a shaft member provided at the end of the rocking sheet guide member 10 with respect to the supporting member 7. 18 is supported. Then, the rocking paper guide member 10 is supported by the two shaft members 13 and 18 facing each other in the front-back direction of the paper conveyance direction, and the rocking paper guide member is rocked about the shaft in the width direction of the paper. To be able to.

[0020]

[Embodiment 2] In the embodiment of the present invention, the case where the swinging paper guide member arranged in the paper aligning device is provided in the device which conveys the paper to one side has been described. However, as shown in FIG. It is also possible to arrange the sheet aligning device with respect to the confluence portion of the sheet conveying path and configure a mechanism that uses one swinging sheet guide member to cope with the aligning action of the sheets. In the example shown in FIG. 9, the vertical guide member 40 is arranged at a position where the sheets sent from the two paper feed trays 35 and 37 merge with the vertical sheet aligning device 30. Further, in the vertical direction paper aligning device 30, a registration roller device 31 is arranged at a portion (downstream part) above the confluence portion, and the paper aligned by the vertical direction paper aligning device is passed through the registration roller device 31. A mechanism for sending the image toward an image transfer portion or the like corresponding to the photosensitive drum is configured. further,
In the paper feed trays 35 and 37 for feeding paper toward the vertical paper aligning device 30, paper feed devices 36 and 38 are arranged corresponding to the paper feed units from the respective trays,
The roller device that constitutes the paper separating device of the paper feeding device is used as a pre-registration roller device so as to function as a paper alignment device with the registration roller device 31, and the leading end portion of the paper is applied to the registration roller device 31. Guide plates 3 on both sides of the longitudinal guide member for guiding toward
2 and 33 are arranged.

The vertical guide member 40 arranged in the vertical paper aligning device 30 is provided with guide surfaces 41 and 42 on both side surfaces of the main body in order to guide the paper from the paper feed trays arranged facing each other. The swing shaft 45 is arranged at the bottom of the main body. In addition, the vertical guide member 40
10, the vertical guide member 40 is supported via the swing shaft 45, as shown in FIG. Then, as shown in FIG. 9, it is attached to a holder member 47 supported by a support shaft 46 below the swing shaft 45 supporting the vertical guide member 40, and is provided below the holder member 47. Spring 4 on each side of arm 48
9, 49a are arranged. Therefore, the vertical guide member 40 provided via the supporting means as shown in FIG. 10 can perform the action of rotating the vertical guide member with respect to the swing shaft 45, and can rotate around the support shaft 46. Since the swing shaft 45 is swingably provided, the vertical guide member can be swung on either side of the left and right paper feed trays.

In addition to constructing the apparatus shown in FIGS. 9 and 10, in the present invention, FIG.
Means for supporting the longitudinal guide member may also be configured, as shown at 12. In the vertical guide member 40a shown in FIG. 11, two elongated holes 50 and 51 corresponding to the moving direction of the sheet are arranged in the lower part of the main body, and two shaft members 52 and 53 corresponding to the elongated holes. Are arranged. By using the vertical guide member 40a shown in FIG. 11, for example, as shown in FIG. 12, the paper is conveyed in two paper feed trays arranged to face the vertical paper aligning device. When the center lines 55 and 56 are not aligned with each other, the loops are used to align the swinging fulcrums of the vertical guide members with respect to the sheets sent from the respective sheet feeding trays and perform the aligning action on the sheets. This is because the guide surface of the vertical guide member can be pressed uniformly from the back surface of the.

In the example shown in FIG. 12, the paper feed tray 35 is disposed so as to face the vertical paper aligning device.
With respect to 37, paper feed devices 36 and 38 are arranged corresponding to the central portions of the papers stored in the respective trays.
Then, the center line 5 of the paper feeding portion of the paper feeding devices 36 and 38
Vertical guide member 40a in a state of matching with 5, 56.
Two shafts 52, 53 for supporting the above are disposed, and the two shafts 52, 53 are provided in the lower portion of the longitudinal guide member main body to form elongated holes 50, 51.
Is engaged with. Therefore, the paper feed tray 3 on the right side of the drawing
When a loop is formed in a state in which the sheet P1 fed from the sheet 5 comes into contact with the guide surface 41 of the vertical guide member, the vertical guide member 4 corresponds to the shape of the loop of the sheet.
0a is swung about the shaft 52, but the other shaft 53
Is ready to play inside the long hole 51. On the other hand, the paper P fed from the paper feeding tray 37 by the paper feeding device 38
2 forms a loop corresponding to the guide surface 42 of the vertical guide member 40a, and the protrusion of the loop presses and swings the vertical guide member. In that case, the vertical guide member 40a is The other shaft 52 is swung through the shaft 53.
Is in a state where play occurs inside the long hole 50.

In the examples shown in FIGS. 11 and 12, the relationship between the shaft for supporting the vertical guide member 40a and the elongated hole can be provided in correspondence with the center line of the sheet conveyance of the sheet feeding device. The two shafts can be positioned exactly in correspondence with the position of the sheet feeding device arranged for each sheet feeding tray. Further, in the vertical sheet aligning device in which the vertical guide member 40a is arranged, as shown in FIG. 9, the two shafts supporting the vertical guide member serve as horizontal spindles via the holder member. A means for supporting and swinging the vertical guide member with respect to the horizontal axis can be configured.

[0025]

Since the sheet aligning device of the image forming apparatus of the present invention is configured as described above, the rocking sheet guide member is arranged with a part of the guide plate in the sheet aligning device cut out. Then, the oscillating paper guide member is oscillated according to the size of the loop formed on the paper, and the guide surface provided on the oscillating paper guide member can apply a pressing action from behind the paper loop. . Even if the loop shape of the sheet is not formed in the width direction of the sheet, the guide surface of the rocking sheet guide member can press the protrusion of the loop of the sheet in accordance with the loop shape. Therefore, it is possible to uniformly apply a force for pushing the paper toward the nip portion of the registration roller device in the width direction of the paper. Therefore, after being aligned by the sheet aligning device of the present invention, the sheet delivered toward the image transfer portion is given a uniform pressing action in the width direction without being affected by the size of the loop formed on the sheet. Therefore, it is possible to accurately set the transfer position of the image on the sheet fed by the registration roller device.

Further, according to the present invention, it is possible to configure a sheet aligning device in the vertical direction so as to correspond to a device for feeding a sheet from a sheet accommodating means such as a sheet feeding tray arranged on both sides. With respect to the vertical guide member arranged in the directional paper aligning device, two guide surfaces are arranged corresponding to the sheet feeding devices on both sides, and the vertical guide member is arranged in accordance with the vertical axis corresponding to the loop formed on the paper. By oscillating, it is possible to perform the feeding action of the paper after alignment in a good state. Further, in addition to constituting a means for supporting the vertical guide member by one shaft, when the size of the paper fed from two directions is different, the vertical guide member is supported by the two shafts. It is also possible to configure a mechanism for supporting the member and swinging the vertical guide member by using an arbitrary shaft corresponding to the size of the paper.

[Brief description of drawings]

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

FIG. 2 is a plan view of the sheet aligning device of FIG.

FIG. 3 is an explanatory diagram of a loop formed on a sheet in the sheet aligning device of FIG.

FIG. 4 is a side view of the swinging paper guide member of the present invention.

FIG. 5 is an explanatory view of a second embodiment of the swinging paper guide member of the present invention.

FIG. 6 is an explanatory view of a third embodiment of the swinging paper guide member of the present invention.

FIG. 7 is an explanatory diagram of a fourth embodiment of the swinging paper guide member of the present invention.

FIG. 8 is an explanatory diagram of another embodiment that supports a swinging paper guide member.

FIG. 9 is an explanatory view of an apparatus for disposing a vertical guide member in a vertical paper aligning apparatus.

10 is an explanatory view of a vertical guide member used in FIG.

FIG. 11 is an explanatory view of another embodiment of the vertical guide member.

12 is a plan view of a vertical paper aligning device using the vertical guide member of FIG.

FIG. 13 is an explanatory diagram showing a state of sheets aligned by a conventional sheet aligning device.

FIG. 14 is a side view of a conventional sheet aligning device.

[Explanation of symbols]

1 paper alignment device, 2 registration roller device, 3
Pre-registration roller device, 10 rocking paper guide member, 11 guide surface, 12 shaft support, 13
Support shaft, 15 horizontal shafts, 20 rocking paper guide members, 21-23 brackets, 26 support shafts,
30 vertical direction paper alignment device, 31 registration roller device, 40 vertical direction guide member, 45 swing shaft,
47 holder member, 52, 53 axis.

Claims (7)

[Claims] 1. A sheet aligning device arranged upstream of an image transfer unit from an image carrier of an image forming apparatus, wherein the sheet aligning device is arranged in a position close to the image carrier. A sheet aligning apparatus configured to position a sheet by forming a loop between the rollers, the sheet aligning apparatus including a pre-registration roller apparatus disposed upstream of the registration roller apparatus. A rocking paper guide member is arranged corresponding to one of the guide plates arranged between the roller devices, and the rocking paper guide member is provided with a guide surface corresponding to a loop of paper, It is supported by a support shaft arranged in a direction perpendicular to the roller axis and is provided so as to be swingable in the width direction of the paper with respect to the support shaft. A sheet aligning device for an image forming apparatus, comprising means for swinging around a support shaft according to the shape of a sheet, and a guide surface of a swinging sheet guide member pressing a loop of a sheet from behind. 2. The sheet aligning apparatus for an image forming apparatus according to claim 1, wherein the swinging sheet guide member is provided with a unit for preventing the swinging sheet guide member from tilting via a support shaft in a state where there is no sheet. 3. A support shaft for supporting the rocking paper guide member is arranged at a central portion in the width direction of the paper conveyance path, and the rocking paper guide member is rocked in the paper width direction about the support shaft. The sheet aligning device of the image forming apparatus according to claim 1, wherein the sheet aligning device is moved. 4. A support means for supporting the swinging paper guide member by a horizontal axis parallel to the axis of the roller of the registration roller device is provided, and the swinging paper guide member is provided on two axes orthogonal to each other. The sheet aligning device of the image forming apparatus according to claim 1, wherein the sheet aligning device supports the sheet aligning device so as to be swingable. 5. A means for supporting the oscillating paper guide member by two orthogonal support shafts is provided, and a guide surface of the oscillating paper guide member is a sheet for a oscillating action with respect to the axis of the roller of the registration roller device. 5. A sheet aligning device for an image forming apparatus according to claim 4, further comprising urging means for urging the loop of FIG. 6. The sheet aligning device is arranged at a position for vertically transporting the sheet, the sheet is fed toward the sheet aligning device from two opposite directions, and the sheet is transported in each direction. A means for imparting an aligning action is provided, and a vertical guide member having two vertical guide surfaces is provided with respect to the paper aligning device, and a width of the paper is provided with respect to the vertical guide member via a vertical axis. 2. The sheet aligning device for an image forming apparatus according to claim 1, further comprising means for supporting the sheet so as to be swingable in a predetermined direction. 7. A device for feeding a sheet toward a sheet aligning device from two facing sides, wherein two vertical axes are provided with respect to a vertical guide member in correspondence with a center position of the sheet fed from the facing side. 7. The sheet aligning device of the image forming apparatus according to claim 6, wherein the vertical guide member is configured to swing via one vertical axis in accordance with the sheet size.