JP2003063696A - Paper feeding device, and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simply and properly conduct adjustment to inclination of a reference line for skew correction. SOLUTION: This paper feeding device is provided with a paper arranging part 26 having a side guide 36 to set the reference line Jk along a paper carrying direction on one side of a paper carrying passage to make a paper arranging action to set a side end of paper 35 to the reference line Jk set by the side guide 36, an inclination adjusting means having a rotation support point P on the downstream side of the paper arranging part 26 in a carrying direction Y to adjust the inclination of the reference line Jk to the carrying direction Y by rotating the side guide 36 around the rotation support point P, and a side shift means to move paper 35 sent from the paper arranging part 26 perpendicularly to the carrying direction Y. The rotation support point P of the inclination adjusting means is set on a center line Jc in paper width as the paper is moved by the side shift means.

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 a copying machine or a printer, and more particularly to a sheet feeding apparatus used in the image forming apparatus.

[0002]

2. Description of the Related Art An image forming apparatus such as a copying machine or a printer is equipped with a sheet feeding device for feeding a sheet along a predetermined path. A plurality of conveyance rollers are arranged on the conveyance path of the sheet feeding device. Each of the transport rollers is rotationally driven by a motor or the like as a drive source, and the paper is transported from the upstream side to the downstream side in the transport direction in accordance with the rotational driving of the transport rollers.

In an image forming apparatus provided with such a sheet feeding device, a so-called skew of the sheet, which is a skew of the sheet being conveyed, may occur. If the paper is sent to the image output position while skewed,
The image is output in an inclined state with respect to the paper. Therefore, a sheet aligning device that corrects the skew of the sheet being conveyed is used.

One of the aligning methods by the sheet aligning device is a method of correcting the skew by using the side edge of the sheet as an alignment target. In this alignment method, a side guide is provided on one side of the paper transport path along the transport direction, and skew rollers are arranged in the paper transport path. Then, the side edge of the sheet is abutted against the side guide to correct the sheet skew (side skew).

[0005]

By the way, in order to properly correct the skew of the sheet in the sheet aligning apparatus, the reference line of the side guide is set straight with respect to the conveying direction of the sheet and the sheet is aligned with this reference line. It is necessary to run along the side edge. At that time, if the reference line of the side guide is inclined with respect to the conveyance direction, the sheet is conveyed with this inclination,
As a result, the skew correction becomes inadequate.

Therefore, for example, in Japanese Unexamined Patent Publication No. 7-206225, a sheet aligning device is constructed as one unit, and the sheet aligning device is attached to the main body of the image forming apparatus so as to be able to be drawn out. An image forming apparatus is disclosed in which a side guide of a sheet aligning device is abutted against a stopper member on the image forming apparatus main body side to position the side guide.

However, in the image forming apparatus disclosed in the above publication, since the side guide is in contact with the stopper member on the image forming apparatus main body side, the direction (tilt) of the reference line of the side guide is adjusted. It is necessary to move the stopper member delicately. Therefore, the work of adjusting the inclination of the reference line becomes very troublesome and difficult. Also, when the stopper member is actually moved to adjust the inclination of the reference line, the paper position in the direction orthogonal to the transport direction, that is, the side registration may be displaced depending on the adjustment method, and adjustment for that is necessary separately. Become.

[0008]

A sheet feeding device according to the present invention has a reference member on one side of a sheet conveying path for setting a reference line along the sheet conveying direction, and is set by this reference member. A sheet aligning unit that aligns the sheets so that the side edges of the sheets are aligned with the reference line, and a rotation fulcrum is provided downstream of the sheet aligning unit in the transport direction. The tilt adjusting unit includes a tilt adjusting unit that adjusts the tilt of the reference line with respect to the conveying direction by rotating the sheet, and a side shift unit that moves the sheet fed from the sheet aligning unit in a direction orthogonal to the conveying direction. The rotation fulcrum is set at a position on the center line of the sheet width when the sheet is moved by the side shift means. The present invention is also an image forming apparatus including the sheet feeding device having the above-described configuration, which transfers an image onto a sheet fed from the sheet aligning means and moved by the side shift means in a direction orthogonal to the conveying direction. In addition to providing the means, the rotation fulcrum of the tilt adjusting means is set at a position where the center line of the paper width and the image transfer axis of the image transfer means intersect.

In the paper feeding apparatus having the above-mentioned structure, the rotation fulcrum for adjusting the inclination of the reference line is set at the position on the center line of the paper width when the paper is moved by the side shift means. When the reference member is actually rotated around the rotation fulcrum to adjust the inclination of the reference line, the center of the paper width of the paper aligned (skew correction) by the paper alignment means is at the rotation fulcrum position. It will progress toward. Therefore, it is possible to adjust the inclination of the reference line without shifting the sheet position (lead registration, side registration) in the transport direction or the direction orthogonal to this. Further, in an image forming apparatus equipped with such a sheet feeding device, the rotation fulcrum of the tilt adjusting means is set at a position where the center line of the sheet width and the image transfer axis of the image transfer means intersect with each other, so that the image It is possible to adjust the inclination of the reference line without shifting the paper position on the transfer axis in the transport direction or the direction orthogonal thereto.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a schematic diagram showing a configuration example of an image forming apparatus to which the present invention is applied. The illustrated image forming apparatus 1
Is composed of an image reading unit 2, an image forming unit 3, and a sheet feeding device 4.

The image reading section 2 reads an image of a document set on a transparent document table (platen glass). The image reading unit 2 includes, for example, an optical scanning system including a lamp, a mirror and a carriage, a lens system for forming an optical image read and scanned by the optical scanning system, and an optical image formed by the lens system. An image reading sensor (for example, 3 line C
And a CD sensor).

The image forming section 3 includes four photosensitive drums 5, 6, 7, and 8 corresponding to K (black), Y (yellow), M (magenta), and C (cyan) colors, and the respective photosensitive drums. Four primary transfer rollers 9, 10, 1 corresponding to the body drum
1, 12, an intermediate transfer belt 13, and a secondary transfer roller 1
4, a vacuum transport unit 15, and a fixing device 16 are provided in a four-tandem tandem system.

A charger and a laser writing device (laser R) are provided around the photosensitive drums 5, 6, 7, and 8, respectively.
OS), a developing device, a cleaner, etc. are arranged. The charging device uniformly charges the surface of the photosensitive drum, and the laser writing device forms an electrostatic latent image on the surface of the photosensitive drum charged by the charging device by laser irradiation. Further, the developing device supplies toner as a developer to the surface of the photoconductor drum to visualize (develop) the electrostatic latent image to form a toner image, and the cleaner does not need to remain on the photoconductor drum. It removes toner.

On the other hand, each primary transfer roller 9,
10, 11, and 12 are arranged in the vicinity of the corresponding photoconductor drums 5, 6, 7, and 8 so as to face each other with the intermediate transfer belt 13 interposed therebetween. These primary transfer rollers 9,
10, 11, 12 are the photosensitive drums 5, as described above.
The toner images formed on 6, 7, and 8 are transferred (primary transfer) to the intermediate transfer belt 13. The intermediate transfer belt 13 is stretched in a loop by a plurality of (five in the illustrated example) belt supporting rollers.

The secondary transfer roller 14 is the intermediate transfer belt 1.
It is arranged so as to face one of the belt supporting rollers for supporting the belt 3. The secondary transfer roller 14 and the belt supporting roller constitute an image transfer section. In this image transfer portion, the intermediate transfer belt 13 and the sheet are nipped between the secondary transfer roller 14 and a belt supporting roller facing the secondary transfer roller 14, and the toner supplied to the secondary transfer roller 14 in this state is The toner image is transferred (secondarily transferred) from the intermediate transfer belt 13 to the sheet by the electric charge (or voltage) having the opposite polarity. The transfer position (secondary transfer position) of this toner image becomes the image output position in the image forming section 3.
The vacuum transport unit 15 transports the sheet on which the toner image is transferred by the secondary transfer roller 14 to the fixing device 16. The fixing device 16 fixes the toner image on the sheet by heating and pressing.

On the other hand, the sheet feeding device 4 includes the first tray 1
Among the papers stored in the second tray 18, the third tray 19 and the third tray 19, the paper of the tray selected by the user operation or the paper of the tray selected by the automatic selection function is set in a predetermined path. The paper is fed in. In the vicinity of each tray 17, 18, 19
The corresponding delivery rollers 20, 21, 22 are provided. Each of the delivery rollers 20, 21, 2
2 is for separating the called sheets from the corresponding trays 17, 18 and 19 one by one and sandwiching the called sheets, and sending the sheets to the downstream side in the sheet conveying direction. An operation panel 23 operated by a user is provided near the image reading unit 2.

Here, each of the delivery rollers 20 and 2
In the series of paper transport paths R1 to R5 from the paper feed position of the sheets 1 and 22 to the discharge tray 24 via the image output position in the image forming section 3, rollers for paper transport are appropriately arranged. Has been done. The paper stored in the first tray 17 is sent out by the sending-out roller 20, and then sent to the merging / conveying unit 25 via the first paper conveying path R1. Further, the sheets accommodated in the second tray 18 are sent out by the sending-out roller 21, and then the merging / conveying unit 2 passes through the first sheet conveying path R1.
It is sent to 5. On the other hand, the sheets accommodated in the third tray 19 are fed by the delivery roller 22 to the merging / conveying unit 2
Directly sent to 5.

Further, the sheet sent to the merging / conveying section 25 is sent to the image output position of the image forming section 3 via the second sheet conveying path R2. Further, the sheet that has passed the image output position is sent to the fixing device 16 by the vacuum conveyance section 15, and then is ejected to the ejection tray 24 via the third sheet conveyance path R3. On the other hand, the paper on which images are formed on both sides (first side and second side) is the fixing device 16
After passing through the sheet, the sheet is sent to the double-sided reversing unit 28 via the fourth sheet transporting path R4, the direction of the sheet is changed for reversing the sheet, and then the sheet is merged again via the fifth sheet transporting path R5. It is sent to the transport unit 25.

In the sheet conveying paths R1 to R5, a sheet aligning section 26 and a registration roller 27 are arranged in the second sheet conveying path R2. The sheet aligning unit 26
This is a portion for performing skew correction of the sheet conveyed along the second sheet conveying path R2. The configuration of the sheet aligning unit 26 will be described later. The registration roller 27 is composed of a pair of rollers held in pressure contact with each other, and holds the sheet between the pair of rollers while feeding the sheet to the image output position by the rotation of the roller.

When the registration roller 27 feeds the paper, the timing adjustment means (not shown) adjusts the arrival timing of the paper with respect to the image output position. The timing adjusting means varies the conveyance speed of the paper by the registration roller 27 based on the timing when a paper passage sensor (described later) provided in front of (on the upstream side of) the registration roller 27 detects the passage of the paper. According to the arrival timing of the toner image at the image output position, the arrival timing of the paper at the image output position is adjusted.

Further, curl correction units 29 and 30 are provided on the paper transport paths R3 and R5, respectively. The curl correction units 29 and 30 are for correcting the curl of the paper when the toner image is fixed by the fixing device 16.

Subsequently, the image forming apparatus 1 having the above structure
The operation of will be described. First, when the image of the original is read by the image reading unit 2, the toner image is formed by the image forming unit 3 based on the image signal obtained by the reading. In this image forming unit 3, the four photosensitive drums 5,
While rotating 6, 7, and 8, K, Y, and K on the surface of each photosensitive drum 5, 6, 7, and 8 by a charging device, a laser writing device (laser ROS), and a developing device corresponding to each.
Toner images of M and C are sequentially formed. The toner images of the respective colors formed in this way are transferred to the primary transfer rollers 9, 10, 1.
The images 1 and 12 are sequentially transferred onto the intermediate transfer belt 13 in an overlapping manner. As a result, a multicolor (full color) toner image in which four color toners are superposed is formed on the intermediate transfer belt 13. The toner image thus formed on the intermediate transfer belt 13 is carried by the intermediate transfer belt 13 and sent to the image output position (the secondary transfer position by the secondary transfer roller 14).

On the other hand, the paper of the tray selected by the user using the operation panel 23 or the paper of the tray selected by the automatic selection function is registered by the registration roller 2 at the timing when the toner image reaches the image output position.
Sent by 7. For example, if the tray selected as described above is the first tray 17, the sheet sent by the sending roller 20 is sent to the merging / conveying unit 25 via the first sheet conveying path R1, and The sheet is sent to the image output position by the registration roller 27 via the second sheet conveyance path R2.

As a result, at the image output position of the image forming section 3, the toner image (full color image) carried on the intermediate transfer belt 13 is collectively transferred (secondarily transferred) onto the paper by the secondary transfer roller 14. After that, the sheet is sent to the fixing device 16 by the vacuum transport unit 15, where the toner image is fixed there, and then discharged to the discharge tray 24 via the third sheet transport path R3.

Further, the paper on which images are formed on both sides (paper to be copied on both sides) is sent to the double-sided reversing unit 28 via the fourth paper conveyance path R4, and the direction is changed there for the front and back reversal. Then, the sheet is sent to the fifth sheet conveyance path R5. After that, the sheet is conveyed along the fifth sheet conveying path R5, and then the timing is adjusted by the rotation of the feed roller 31, and the sheet is fed again to the merging / conveying unit 25. After that, after the toner image is transferred and fixed on the paper in the same manner as described above, the third image is formed.
The paper is discharged to the discharge tray 24 via the paper transport path R3.

FIG. 2 is a schematic view showing the arrangement of the sheet aligning section 26 according to the embodiment of the present invention. In FIG. 2, a plurality of (three in the illustrated example) skew rollers 32, 33, 34 are sequentially provided from the upstream side to the downstream side in the sheet transport direction Y. These skew rollers 32, 33, 34 are arranged so as to be inclined at a predetermined angle with respect to the sheet transport direction Y. Also, each of the skew rollers 32, 33,
Reference numeral 34 is composed of a drive roller and a pinch roller which are held in pressure contact with each other. Of these, the drive roller is arranged as tilted as shown, but the pinch roller is arranged without tilt. Further, the drive roller and the pinch roller are arranged so as to sandwich the paper conveyance path from above and below.

As shown in FIG. 3, the skew rollers 32, 33, and 34, which are a pair of upper and lower rollers, have a biasing force applied to the pinch rollers by a spring or the like, and the sheet 3
By nipping (holding) 5 and rotating in the nip state, a conveying force in the oblique direction K is applied to the sheet 35 on the sheet conveying path. On the other hand, a long side guide 36 is arranged along the transport direction Y on one side (right side in the drawing) of the paper transport path along which the paper 35 is transported. Side guide 36
Has a substantially U-shaped cross section, and integrally has a reference surface 37 along the longitudinal direction of the guide. The side guide 36 corresponds to the reference member in the present invention,
A reference line Jk for skew correction is set by the reference surface 37 of the side guide 36. This reference line J
k is an axis passing through the reference surface 37 of the side guide 36,
The direction is set along the transport direction Y.

A paper side edge detection sensor 38 is provided on the downstream side of the side guide 36, located inside the paper transport path by a few millimeters from the reference surface 37 (reference line Jk). The sheet side edge detection sensor 38 is arranged between the most downstream skew roller 34 and the registration roller 27 in the sheet transport direction Y. The registration roller 27 is supported by a side shift mechanism (not shown) so as to be movable in a direction (arrow direction in the drawing) orthogonal to the transport direction Y. Further, a paper passage detection sensor 39 is arranged in front of the registration roller 27 in the transport direction Y.

In the sheet aligning section 26 having the above structure, the sheet 35 fed from the upstream side in the transport direction Y is sequentially nipped by the skew rollers 32, 33 and 34. At that time, paper 3
As shown in FIG. 3, 5 is a position shown by a dashed line in the drawing from a position shown by a broken line, that is, the side guide 36 side by the rotation of each of the skew rollers 32, 33, 34 and the accompanying conveying force in an oblique direction. Be squeezed into. As a result, the side edge of the sheet 35 is abutted against the reference surface 37 of the side guide 36. As a result, the side edge of the sheet 35 is aligned along the reference line Jk set on the reference surface 37 of the side guide 36, and the skew of the sheet (side skew) is corrected thereby. Further, the sheet 35 skew-corrected by the sheet aligning unit 26, the reference line J by the side guide 36.
The sheet is conveyed to the downstream side in the conveying direction Y along the direction k, and is sequentially sent to the registration roller 27 and the secondary transfer roller (hereinafter abbreviated as transfer roller) 14.

Further, when the leading edge of the sheet 35 fed from the sheet aligning section 26 is detected by the sheet passage detection sensor 39, and the sheet side edge detection sensor 39 is turned on (ON), a predetermined time elapses from the sensor ON timing. By the nip releasing means (not shown), the skew roller 32,
The nip state of 33 and 34 is released. The predetermined time in this case is appropriately set in consideration of the time required until the sheet 35 skew-corrected by abutting against the side guide 36 is nipped by the registration roller 27.

Subsequently, before the sheet 35 is fed to the transfer roller 14 by the rotation of the registration roller 27, a side shift mechanism (not shown) moves the sheet 35 together with the registration roller 27 in a direction orthogonal to the transport direction Y (left in FIG. 3). Direction) to perform side shift operation. During this side shift operation, the side edge of the sheet 35 is detected by the sheet side edge detection sensor 38, and when the sheet side edge detection sensor 38 is turned on by this, the side shift operation (of the sheet 35 of the sheet 35 is performed after a predetermined time from this sensor ON timing. Move) ends. The side shift operation is performed to align the position of the sheet 35 with the position of the toner image transferred onto the sheet 35 in the direction orthogonal to the transport direction Y.

In the sheet aligning section 26 having such a structure and operation function, the side guide 36 is rotatably supported around a rotation fulcrum P provided on the downstream side of the side guide 36 in the transport direction Y. There is. The rotation fulcrum P is a center line J of the sheet width when the sheet 35 is moved by a side shift mechanism (not shown) when the sheet conveyance path is viewed in plan.
It is set to the position on c. The center line Jc of the paper width is
The size of the paper in the width direction (direction orthogonal to the transport direction Y)
It is an axis line that passes through the center of the paper when it is divided into two equal parts by a straight line parallel to the transport direction Y. Further, when viewed from the positional relationship with the transfer roller 14, the rotation fulcrum P is set at a position where the center line Jc of the sheet width and the central axis Jr of the transfer roller 14 intersect.

FIG. 4 is a perspective view showing the support structure of the side guide 36 in the sheet aligning section 26. In FIG.
The side guide 36 is attached to a long guide support member 40. The guide support member 40 is formed in a substantially U-shaped cross-section, and an adhesive material is attached to the inner upper surface of the U-shaped section.
The side guide 36 is fixed by using a fixing means such as a double-sided tape. At one end side of the side guide 36, a sheet take-in port 41 which is opened in a substantially C-shape is provided so that the sheet can be taken in smoothly.

A base plate 42 is attached to the lower surface of the guide support member 40. The base plate 42 is fixed to the guide support member 40 by fixing means such as adhesion and screwing. Base plate 42
One end of the side guide 36 extends to the downstream side in the transport direction with respect to the end of the side guide 36. Further, the side guide 36 is supported rotatably about a rotation fulcrum P via a guide support member 40 and a base plate 42. This rotation fulcrum P
Let “P1” be the intersection with the center line jc of the paper width on the center axis Jr of the transfer roller, and “P2” be the intersection with the center axis Jr of the transfer roller on the center line Jc of the paper width. , Are set at axial positions connecting these intersections P1 and P2.

On the other hand, in the longitudinal direction of the guide support member 40, a rotation operation mechanism 44 is provided on the side opposite to the rotation fulcrum P (upstream side in the sheet alignment section 26 in the transport direction). In this rotation operation mechanism 44, the guide support member 4
Fixing brackets 45, 0 on the upper surface and the lower surface, respectively.
45 is fixed using a fixing means such as an adhesive. Each of the fixing brackets 45, 45 is formed in a U shape. Receiving pins (round pins) 46, 46 are attached to the fixing brackets 45, 45, respectively. Both end portions of the receiving pins 46, 46 are fixed to the corresponding fixing brackets 45, 45 in a fitted state. Further, the receiving pins 46, 46 are arranged substantially coaxially with each other with the side guide 36 and the guide support member 40 interposed therebetween.

Further, a shaft support bracket 47 is arranged at a portion facing the fixed brackets 45, 45. The shaft support bracket 47 is fixed to a side frame (not shown) of the apparatus main body by screwing. An adjustment shaft 48 is rotatably engaged with and supported by the shaft support bracket 47. The adjusting shaft 48 is arranged substantially parallel to the above-mentioned receiving pins 46, 46. An operation knob 49 is attached to one end (upper end) of the adjustment shaft 48 via a not-shown one-way clutch, and a ratchet 50 having continuous outer peripheral teeth in a sawtooth shape is fixed to the other end (lower end) thereof. It is installed in. The ratchet 50 rotates integrally with the adjusting shaft 48.

Further, two rotary cams 51, 51, which are located between the operation knob 49 and the ratchet 50, are fixed to the adjusting shaft 48 in a fitted state. These rotary cams 51, 51 rotate integrally with the adjustment shaft 48, and are arranged at a predetermined interval in the axial direction of the adjustment shaft 48. In addition, each rotary cam 51, 5
1 has a stepped portion at one location on the outer peripheral surface of the cam, and the diameter dimension from the cam center (rotation center) to the outer peripheral surface of the cam is continuously changed in the circumferential direction at the stepped portion as a boundary. It has a shape (contour). These two rotary cams 51, 51
Is provided corresponding to the two fixing brackets 45, 45 described above.

The fixed brackets 45, 45 and the shaft support bracket 47 are connected by two connecting shafts 52, 52. These connecting shafts 52, 52
Are arranged in pairs one above the other. Connecting shaft 5
One end portions of the reference numerals 2, 52 are fixed to the corresponding fixing brackets 45, 45 in a fitted state. Further, the other end of each of the connecting shafts 52, 52 penetrates the shaft support bracket 47, and the shaft support bracket 47.
It is arranged in a protruding state on the outside of. In this state, the two connecting shafts 52, 52 are attached to the shaft support bracket 47.
It is movably supported in the axial direction while being fitted to.

Furthermore, compression type coil springs 53, 53 are wound around the other ends of the connecting shafts 52, 52 using washers and retaining rings (E-rings). The biasing force (spring force) of the coil springs 53, 53 acts so as to pull the fixed brackets 45, 45 toward the shaft support bracket 47 side via the corresponding connecting shafts 52, 52. The receiving pins 46, 46 are held in pressure contact with the outer peripheral surfaces of the corresponding rotating cams 51, 51 by the pulling force (biasing force) of the coil springs 53, 53.

On the other hand, the ratchet 50 has a hooking claw 54 having a substantially U shape. The hooking claw 54 is swingably supported by a hat-shaped bracket 55 via a support pin 56. The bracket 55 is fixed to a side frame (not shown) of the apparatus main body by screwing. The ratchet 50 and the hook 54
With respect to the ratchet mechanism consisting of, the rotation direction of the adjusting shaft 48 using the operation knob 49 (the direction in which power is transmitted by the one-way clutch) is set to a direction in which the locked state of the ratchet 50 and the hook 54 can be released. ing.

In the rotary operation mechanism 44 having the above-mentioned structure, when the operation knob 49 is rotated in the clockwise direction (CW direction in the figure), this rotational force is transmitted to the adjusting shaft 48 via a one-way clutch (not shown). To be done. Therefore, when the operation knob 49 is rotated clockwise, the adjustment shaft 48 rotates in conjunction with this. On the other hand, when the operation knob 49 is turned counterclockwise, this rotational force is not transmitted to the adjustment shaft 48 via the one-way clutch (not shown). Therefore, when the operation knob 49 is rotated counterclockwise, the adjustment shaft 48 does not rotate and only the operation knob 49 idles.

When the adjusting shaft 48 is rotated by using the operation knob 49, the ratchets 50 and 2 are integrally formed with the adjusting shaft 48.
The two rotating cams 51, 51 rotate. At this time, if the ratchet 50 rotates integrally with the adjustment shaft 48,
Accordingly, the locking position of the hooking claw 54 with respect to the outer peripheral teeth of the ratchet 50 is sequentially displaced. Therefore, the adjustment shaft 48 can be intermittently rotated (by a substantially constant angle) using the operation knob 49. Further, when the adjustment shaft 48 is stopped rotating at an arbitrary position, the hook claws 54 are always locked to the outer peripheral teeth of the ratchet 50, so that the rotation deviation of the adjustment shaft 48 due to vibration or the like is prevented. You can Further, since the rotation direction of the adjustment shaft 48 using the operation knob 49 is limited to one direction by the one-way clutch, there is no fear that the ratchet 50 is mechanically damaged by the reverse rotation of the adjustment shaft 48.

On the other hand, when the two rotary cams 51, 51 rotate integrally with the adjusting shaft 48, the receiving pins 46, 4
6 is displaced according to the outer peripheral shape of the rotating cams 51, 51. That is, from the state where the receiving pins 46, 46 are engaged with the stepped portions on the outer peripheral surfaces of the rotating cams 51, 51, the adjustment shaft 4
When the rotary cams 51, 51 are rotated integrally with the bearing 8, the receiving pin 4 is resisted by the biasing force of the coil springs 53, 53.
6, 46 are gradually extruded in the direction away from the adjustment shaft 48. Then, when the rotary cams 51, 51 rotate exactly once (rotate 360 °), the receiving pins 46, 46 are pulled back in the direction of approaching the adjustment shaft 48 by the level difference of the stepped portion of the outer peripheral surfaces of the rotary cams 51, 51. This pullback is performed by the biasing force of the coil springs 53, 53.

From this, the displacement direction of the receiving pins 46, 46 due to the rotation of the rotary cams 51, 51 becomes the direction of contacting with and separating from the adjusting shaft 48. However, since the adjusting shaft 48 is rotated only in one direction by the action of a one-way clutch (not shown), the receiving shafts 46, 46 are always in contact with the rotating cams 51, 51 except for the stepped portion. The receiving pin 4 in the direction away from the adjustment shaft 48 (the direction pushed out by the rotating cams 51, 51)
6,46 will be displaced.

Further, when the receiving pins 46, 46 are displaced according to the rotation of the rotary cams 51, 51, the fixing brackets 45, 45 are integrated with the receiving pins 46, 46.
Is also displaced. Since the fixing brackets 45, 45 are fixed to the guide support member 40, the fixing bracket 4
When 5 and 45 are displaced, the guide support member 40 rotates together with the side guides 36 around the rotation fulcrum P accordingly.

From the above, the side guide 36 can be rotated about the rotation fulcrum P by rotating the operation knob 49 in the clockwise direction to rotate the adjustment shaft 48. As a result, the orientation of the reference line Jk (reference surface 37 of the side guide 36) for skew correction changes, so in the paper aligning unit 26 shown in FIGS. 2 and 3, the reference with respect to the paper transport direction Y is used. The inclination of the line Jk can be arbitrarily adjusted (finely adjusted).

Further, as the configuration of the sheet feeding device 4 having the sheet aligning section 26, the rotation fulcrum P for adjusting the inclination of the reference line Jk is the sheet width when the sheet 35 is moved by the side shift mechanism. When the side guide 36 is actually rotated around the rotation fulcrum P to adjust the inclination of the reference line Jk by setting the position on the center line Jc of the sheet, the sheet aligning unit 26 performs alignment (skew). The center portion of the corrected sheet width of the sheet 35 advances toward the rotation fulcrum P position. Therefore, at the position where the rotation fulcrum P is provided in the sheet transport direction Y, the sheet position (side registration) in the direction orthogonal to the sheet transport direction Y or the leading edge position (lead registration) of the sheet in the sheet transport direction Y is set. It is possible to appropriately correct the skew of the sheet by adjusting the inclination of the reference line Jk without causing a deviation.

Further, as the configuration of the image forming apparatus 1 including the sheet feeding device 4, the rotation fulcrum P is set at the position where the center line Jc of the sheet width and the center axis Jr of the transfer roller 14 intersect. Paper 3 fed to transfer roller 14
The inclination of the reference line Jk can be adjusted without shifting the position of 5 in the transport direction Y or in the directions orthogonal to this (the lead registration direction and the side registration direction). As a result, at the central axis Jr of the transfer roller 14, the transfer roller 1 is prevented from being displaced in the lead registration and the side registration.
By adjusting the inclination of the reference line Jk at a right angle to the central axis Jr of No. 4, it is possible to appropriately correct the skew of the sheet.

On the other hand, for example, in the sheet aligning unit 26 shown in FIGS. 2 and 3, the position adjusting mechanism (not shown) is provided at both ends (upper and lower ends in the figure) of the side guide 36, and the position is adjusted. When the side guide 36 is arbitrarily tilted by the adjusting mechanism to adjust the inclination of the reference line Jk, the position toward the center of the sheet width is orthogonal to the transport direction Y every time the inclination of the reference line jk is adjusted. There is a risk of shifting in the direction of doing. Therefore, in addition to adjusting the inclination of the reference line jk,
It is necessary to adjust lead registration and side registration.

In the above embodiment, the aligning method for correcting the skew of the sheet by using the skew rollers 32, 33, 34 and the side guide 36 has been described as an example.
The present invention can also be applied to those employing other matching methods. Hereinafter, a specific application example will be described with reference to FIG.

In FIG. 5, three shift rollers 61, 62, 63 are provided at different positions in the transport direction Y. These shift rollers 61, 62, 63 are arranged along the transport direction Y. The shift roller 61 is attached to the rotary shaft 64. This shift roller 61
Is rotationally driven by a carry motor 65 via a rotary shaft 64, and at the same time is carried by a shift motor 66 in the carry direction Y.
It is configured to be moved in a direction orthogonal to (left and right direction in the figure). The position of the shift roller 61 in the direction orthogonal to the transport direction Y can be detected by the home position sensor 67.

Similarly, the shift roller 62 is configured to be rotationally driven by the carry motor 69 via the rotary shaft 68 and moved in the direction orthogonal to the carry direction Y by the shift motor 70. Is driven to rotate by a carry motor 72 via a rotary shaft 71 and moved in a direction orthogonal to the carry direction Y by a shift motor 73. The positions of the shift rollers 62 and 63 in the direction orthogonal to the transport direction Y can be detected by the corresponding home position sensors 74 and 75.

The above three shift rollers 61, 62, 63
Is composed of a pair of upper and lower rollers, and is configured to apply a conveying force to the paper 76 by rotating the paper 76 while nipping (sandwiching) the paper 76 between these rollers. The nip state of the sheet by each shift roller 61, 62, 63 can be individually released by a nip release mechanism (not shown) using a solenoid as a drive source.

In the vicinity of the shift rollers 61, 62, 63, paper side edge detection (hereinafter abbreviated as detection sensor) sensors 77, 78, 79 are arranged, respectively. These detection sensors 77, 78, 79 include shift rollers 61,
The sensor detects the side edge of the paper sheet 76 conveyed by 62 and 63, and is composed of, for example, an optical sensor in which a light emitting element and a light receiving element are combined. Detection sensors 77, 78,
79 is arranged in a straight line along the paper transport direction Y,
A reference line Jk for skew correction is set by connecting these sensor detection points.

On the other hand, a transport roller 80 is arranged in front of the shift roller 61 (upstream side in the transport direction Y). Further, on the downstream side of the shift roller 63, a registration roller 81 that feeds a sheet to a transfer position of an image by a transfer roller (not shown) is arranged. The registration roller 81 is supported by a side shift mechanism (not shown) so as to be movable in a direction orthogonal to the transport direction Y. Further, in the sheet transport direction Y, sheet path sensors 82 and 83 are arranged slightly downstream of the shift rollers 62 and 63, respectively. A side edge sensor 84 for detecting the side edge position of the sheet moved by the registration roller 81 in the direction orthogonal to the transport direction Y is arranged on the reference line Jk slightly downstream of the registration roller 81. ing.

In the above structure, the paper sheet 76 sent by the transport roller 80 from the upstream side in the transport direction Y is first nipped in order by the shift rollers 61 and 62. When the passage of the leading edge of the sheet 76 is detected by the sheet path sensor 82, the shift roller 6 starts from the detection timing.
The sheet alignment operation is performed by the reference numerals 1, 62.

After that, when passage of the leading edge of the sheet 76 is detected by the sheet path sensor 83, the sheet aligning operation by, for example, the shift rollers 61 and 63 or the sheet aligning operation by the shift rollers 62 and 63 is started from the detection timing. Is done. At this time, the two shift rollers for aligning the sheets are in a state of nipping the sheets, and the nip state of the other shift rollers is released.

During the sheet aligning operation, the movement of each shift roller 61, 62, 63 is controlled under the following conditions. That is, when the detection sensor 77 does not detect the sheet 76, the shift roller 61 is moved to the right side in the drawing,
When the detection sensor 77 detects the sheet 76, the shift roller 61 is moved to the left side in the drawing. Similarly, when the detection sensor 78 does not detect the sheet 76, the shift roller 62 is moved to the right side in the figure, and when the detection sensor 78 detects the sheet 76, the shift roller 62 is moved to the left side in the figure. To move. Further, when the detection sensor 79 does not detect the sheet 76, the shift roller 63 is moved to the right side in the figure, and when the detection sensor 79 detects the sheet 76, the shift roller 63 is moved to the left side in the figure. Let

Under such control conditions, the shift rollers 61, 6
2, 63 are reciprocally moved in a direction orthogonal to the transport direction Y, so that the side edge of the sheet 76 is moved to the detection sensors 77, 7 respectively.
It is aligned with a reference line Jk passing through 8,79 detection points. As a result, the sheet skew (side skew) is corrected with the reference line Jk as the aim.

Further, the skew-corrected sheet 7 is also used.
When 6 is nipped by the registration roller 81, the nip state of the sheet by the shift rollers 61, 62, 63 is released at that time, and the registration roller 81 is moved in the transport direction Y in this state.
It is moved by a predetermined amount S in a direction (rightward in the drawing) orthogonal to. As a result, the paper 76 is conveyed in the direction orthogonal to the transport direction Y.
Can be moved to an appropriate position (side shift), and the paper 76 can be fed to the image transfer position by the transfer roller.

When applying to such a matching method,
Each of the detection sensors 77, 78, 79 is mounted on a common sensor support member (not shown), and the sensor support member is used as a reference member, and this sensor support member is rotated about the rotation fulcrum P similarly to the side guide 36. The rotatably supporting point P is movably supported and a mechanism similar to the above-described rotation adjusting mechanism 44 is used.
By adopting the configuration in which the sensor support member is rotated around the center, it becomes possible to realize the simplification of the tilt adjustment as in the previous embodiment.

Further, as the constitution of the sheet feeding device 4, the sheet 76 is moved by the registration roller 81 (side shift).
The rotation fulcrum P of the sensor support member is set at a position on the center line Jc of the sheet width in the state where the image forming apparatus 1 is operated.
As described above, by setting the rotation fulcrum P of the sensor support member at a position where the center line Jc of the sheet width and the center axis Jr of the transfer roller 14 intersect, lead registration and It is possible to adjust the inclination of the reference line Jk without causing a deviation in the side registration.

[0064]

As described above, according to the present invention, as the structure of the sheet conveying means including the sheet aligning means, the rotation fulcrum for adjusting the inclination of the reference line is moved by the side shift means. By setting the position on the center line of the paper width in the state, when the inclination is actually adjusted, the center of the paper width of the paper aligned (skew correction) by the paper alignment means moves toward the rotation fulcrum position. It will progress. Therefore, at the position where the rotation fulcrum is provided in the paper transport direction, it is possible to appropriately correct the skew of the paper by adjusting the inclination of the reference line without causing deviation in the lead registration and the side registration. Become.

Further, as a constitution of an image forming apparatus having such a sheet feeding device, a rotation fulcrum for tilt adjustment is set at a position where the center line of the sheet width and the image transfer axis of the image transfer means intersect. By doing so, it is possible to appropriately correct the skew of the sheet by adjusting the inclination of the reference line without causing a deviation in the lead registration or the side registration on the image transfer axis of the image transfer unit.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a configuration example of an image forming apparatus to which the present invention is applied.

FIG. 2 is a schematic diagram showing a configuration of a sheet aligning unit according to the embodiment of the present invention.

FIG. 3 is a diagram illustrating a sheet alignment operation and a side shift operation.

FIG. 4 is a perspective view showing a support structure of a side guide in a sheet aligning unit.

FIG. 5 is a diagram illustrating another application example of the present invention.

[Explanation of symbols]

1 ... Image forming device, 4 ... Paper feeding device, 14 ... Transfer roller (secondary transfer roller), 27 ... Registration roller, 32,
33, 34 ... Oblique rollers, 35 ... Paper, 36 ... Side guides, 37 ... Reference plane, P ... Rotation fulcrum

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Kei Iwasaka             Fuji Zero, 2274 Hongo, Ebina City, Kanagawa Prefecture             Co., Ltd. Ebina Office (72) Inventor Yutaka Kazama             Fuji Zero, 2274 Hongo, Ebina City, Kanagawa Prefecture             Co., Ltd. Ebina Office (72) Inventor Takuzen Kimura             Fuji Zero, 2274 Hongo, Ebina City, Kanagawa Prefecture             Co., Ltd. Ebina Office F-term (reference) 3F102 AA02 AA10 AA11 AB01 BA02                       BB04 DA05 EA06 FA03

Claims (2)

[Claims] 1. A reference member for setting a reference line along a sheet conveyance direction is provided on one side of a sheet conveyance path, and the sheets are aligned such that the side edges of the sheet are along the reference line set by the reference member. A sheet aligning unit that performs an operation, and a rotation fulcrum provided downstream of the sheet aligning unit in the transport direction, and the reference member is rotated about the rotation fulcrum to tilt the reference line with respect to the transport direction. And a side shift means for moving the paper fed from the paper aligning means in a direction orthogonal to the conveying direction, and a rotation fulcrum of the tilt adjusting means by the side shift means. A sheet feeding device, wherein the sheet is set at a position on the center line of the sheet width when the sheet is moved. 2. An image forming apparatus comprising the sheet feeding device according to claim 1, wherein an image is formed on a sheet fed from the sheet aligning means and moved by the side shift means in a direction orthogonal to a conveying direction. An image transfer means for transferring is provided, and a rotation fulcrum of the inclination adjusting means is set at a position where a center line of the paper width and an image transfer axis of the image transfer means intersect with each other. Image forming apparatus.