JPH11349235A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To correct lateral deviation of a sheet of a double-side image forming mode at high precision by preventing the width of an image forming device main body from being increased caused by the presence of a sheet reversing part of a double-side path. SOLUTION: A sheet reversing part 215 of a double-side path 213 is laterally arranged on the downstream side of a path. The lateral deviation of a sheet S is corrected in the sheet reversing part 215. The correction of the lateral deviation of the sheet S is performed when a reversing roller pair 216 refeeds the sheet S. The reversing roller pair 216 moves the sheet S in a direction perpendicular to the sheet conveying direction on the basis of the information from a reference position setting sensor 230 while pinching the sheet S, and the sheet S is moved to a conveyance reference position.

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 for forming an image on a sheet (recording material) fed one by one, and more particularly to an image forming apparatus capable of forming an image on the front and back surfaces of a sheet. Related to the device.

Incidentally, representatives of this image forming apparatus include, for example, a copying machine, a printer, a facsimile, and the like.

[0003]

2. Description of the Related Art FIG. 7A shows an overall schematic configuration of a conventional image forming apparatus capable of forming an image on both sides of a sheet.

Here, the flow of a sheet in the double-sided image forming mode will be described.

The image forming apparatus is provided with two sheet cassettes 100A and 100B arranged in two upper and lower tiers, and sheets (not shown) stacked and stored in one of them are selectively provided. It is to be fed.

The sheets stacked and stored in the sheet cassettes 100A and 100B are sequentially fed from the uppermost sheet by a feeding roller 101 rotating in a counterclockwise direction. The sheets fed from the cassette are separated and fed one by one by a separation / feed roller pair 102.

[0007] The sheet fed by the separation / feed roller pair 102 is transferred to the registration roller pair 1 in a rotation stopped state.
Reach 03. At this time, the movement of the sheet is stopped when the leading end of the sheet comes into contact with the nip of the pair of registration rollers 103 to form a predetermined amount of loop. By forming this loop, the skewed state of the sheet is corrected.

The skew-corrected sheet is transferred to a toner image transfer section between a photosensitive drum 104 rotating clockwise and a transfer roller 105 by a pair of registration rollers 103 starting to rotate at a predetermined timing. Sent to. Then, the transfer roller 105 transfers the toner image on the photosensitive drum 104 to (the surface of) the sheet passing through the toner image transfer unit.

An image reading optical system (not shown) (when the image forming apparatus is a digital copying machine) or a laser scanner (not shown) is provided on the photosensitive drum 104 rotating clockwise. The light image from the beam printer is projected to form an electrostatic latent image, and this electrostatic latent image is developed by a toner developing unit (not shown).

The sheet on which the toner image has been transferred (the surface image has been formed) has passed through the toner image transfer section.
Sent to. Then, the toner image which has been in an unfixed state is fixed on the sheet surface by being heated and pressed in a process of passing through the fixing nip of the pair of identification fixing rollers 106.

The sheet subjected to the fixing process, which has passed through the fixing nip of the pair of fixing rollers 106, is moved by a sheet discharge roller pair 107 to a sheet reversing section (reversing path) 109 of a two-sided path 111.
It is sent to. At this time, the flapper 108 has opened the sheet reversing unit 109.

The sheet sent to the sheet reversing unit 109 is rotated by a pair of reversing rollers 110 which are rotating normally in the direction indicated by an arrow a.
It is sent in the direction. Forward rotating reversing roller pair 11
0 is reversed just before the trailing edge of the sheet passes through the nip. As a result, the sheet in the sheet reversing unit 109 moves in the direction of arrow b, and the two-sided pass 1
Go into 11

The sheets entering the two-sided path 111 are:
The sheet is sequentially conveyed by the second and third conveying roller pairs 112, 113, and 114, and reaches the registration roller pair 103 in the rotation stopped state. At this time, the movement of the sheet is stopped when the leading end of the sheet comes into contact with the nip of the pair of registration rollers 103 to form a predetermined amount of loop. By forming this loop, the skewed state of the sheet is corrected.

The sheet reversing unit 109 and the double-sided pass 11
The unprocessed back surface of the sheet that has passed through 1 and reached the registration roller pair 103 again faces upward.

The sheet whose skew has been corrected is sent to a toner image transfer unit by a pair of registration rollers 103 which starts rotating at a predetermined timing, and a toner image on a photosensitive drum 104 is passed while passing through the toner image transfer unit. Is the transfer roller 105
Is transcribed.

The sheet on which the toner image has been transferred (the backside image has been formed) has passed through the toner image transfer section, and the fixing roller pair 106
The toner image that has not been fixed in the process of passing through the fixing nip of the pair of identification fixing rollers 106 is fixed on the sheet surface.

The sheet subjected to the fixing process that has passed through the fixing nip of the pair of fixing rollers 106 is discharged to the outside of the apparatus by a fixing discharge roller pair 107 through a discharge path (not shown). At this time, the flapper 108 has opened the discharge path.

By the way, in the case of the present image forming apparatus, the sheet in the double-sided image forming mode after the first image formation in the toner image transfer unit moves along a long path and reaches the toner image transfer unit again. For this reason, a long path is shifted laterally to the moving sheet (a deviation in a direction orthogonal to the sheet conveying direction).
When the lateral shift occurs, the image forming position on the sheet shifts.

As a countermeasure for this, a lateral displacement correcting device 115 for correcting a lateral displacement of a sheet is provided upstream of the two-sided path 111 of the image forming apparatus. Next, the lateral displacement correcting device 115 will be described.

As shown in FIG. 7B, the lateral displacement correcting device 115 includes two left and right lateral displacement correcting members 115A for moving the sheet being conveyed on the basis of the central conveyance in a direction perpendicular to the conveying direction. 115B. Each of the lateral displacement correcting members 115A and 115B is installed on the left and right sides of the two-sided path 111 so as to be movable in a direction (arrows X1 and X2 directions) orthogonal to the sheet conveying direction. Each of the lateral displacement correcting members 115A and 115B moves in the arrow X1 direction or the arrow X2 direction by driving a motor (not shown). At this time, each of the lateral displacement correcting members 115A, 115B
Moves in the same direction in the same amount.

When a sheet enters the double-sided path 111,
The lateral displacement correcting members 115A and 115B are on standby at the side of the two-sided path 111. When the leading edge of the sheet entering the double-sided path 111 passes through the nip of the first conveying roller pair 112, the lateral displacement correcting members 115A and 115B are positioned at predetermined positions in the direction of the arrow X1 (positions corresponding to the sheet size).
Move up to. As a result, the sheet that has entered the two-sided path 111 and has been shifted laterally moves to the correct position (conveying center) of the two-sided path 111, and the lateral displacement is corrected. The lateral displacement correcting members 115A and 115B that have moved to the predetermined positions immediately return to the original positions.

Here, the lateral displacement correcting member 115A,
When the sheet 115B moves in the direction of the arrow X1 to correct the lateral displacement of the sheet, the sheet must be released from the state in which the roller pair is nipped. That is, the lateral displacement correcting member 115
The sheet whose lateral deviation is corrected by A and 115B is passing through the pair of reversing rollers 110 and the pair of first conveying rollers 112. Therefore, the reversing roller pair 110 and the first transport roller pair 112 are in a non-nipping state.

In the case of the reversing roller pair 110, one roller (driven roller) 110a is replaced with the other roller (driving roller).
The roller 110 b
When "a" separates from the roller 110b, it becomes a non-nipping state.
The roller 110a is attached to a support member (pressure release plate) 116 that can rotate about a support shaft 116a.
When the support member 116 drives a solenoid (not shown) (the solenoid is turned on), the roller 110a rotates in a direction away from the roller 110b. When the solenoid is turned off, the roller 110a is urged by an urging spring (not shown) to abut on the roller 110b to be in a pinched state.

The reversing roller pair 110 turns on the solenoid when the sheet detecting sensor 117 installed immediately downstream of the first conveying roller pair 112 detects the leading edge of the sheet, and is in a non-nipping state.

In the case of the first transport roller pair 112, an upper roller (drive roller) having a semicircular shape with a part of the outer periphery cut off
A cut surface 112a is a lower roller (driven roller) 11a.
When it is opposed to 2b, it is in a non-clamped state (state shown).
The first conveying roller pair 112 is in this state until the sheet entering the double-sided path 111 has finished correcting the lateral displacement. That is, the first conveying roller pair 112 is driven immediately after the correction of the lateral deviation of the sheet is completed.

[0026]

However, in the case of the conventional image forming apparatus, since the distance from the lateral displacement correction position to the image forming position is long, a large lateral displacement occurs again on the sheet that has reached the image forming position. Therefore, there is a problem that it is difficult to perform high-accuracy lateral displacement correction.

Since the vertical sheet reversing section 109 of the two-sided path 111 exists at the rear end of the sheet cassettes 100A and 100B, there is a problem that the width (B) of the image forming apparatus main body becomes large.

Accordingly, the present invention has been made in view of the above-described circumstances, and enables high-accuracy lateral displacement correction to be performed on a sheet in a double-sided image forming mode, and that the width of the image forming apparatus main body is smaller than that of a double-sided pass. An object of the present invention is to provide an image forming apparatus that does not increase in size due to the presence of a sheet reversing unit.

[0029]

According to the present invention, there is provided an image forming apparatus comprising: a first-side image-formed sheet fed from a sheet feeding unit and having passed through an image forming unit once; The present invention relates to an image forming apparatus that re-conveys to the image forming unit via a double-sided path for forming.

According to the present invention, in order to achieve the above object, the sheet reversing section in the double-sided pass is arranged horizontally on the downstream side of the path, and the sheet reversing section corrects lateral displacement of the sheet. Features.

[0031]

Embodiments of the present invention will be described below with reference to the drawings.

<First Embodiment> FIG. 1 shows a first embodiment of the present invention.
1 shows an overall schematic configuration of an image forming apparatus (copier) according to the embodiment.

Here, the overall configuration will be described along the flow of the sheet S.

The image forming apparatus is provided with a plurality of paper feed cassettes 200A, 200B, 200C, and 200D, and the sheets S loaded and stored in any of these paper cassettes 200A, 200B, 200C, and 200D.
Are selectively fed.

The sheets S stacked and stored in the sheet cassettes 200A to 200D are sequentially fed out from the uppermost sheet by a feeding roller 201 rotating in a counterclockwise direction. The sheets S fed from the cassette are separated and fed one by one by a separation / feed roller pair 202.

The sheet S fed by the separating / feeding roller pair 202 enters a paper feeding path (vertical path) 203, is conveyed to conveying roller pairs 204a to 204d, and
Move 3 downstream.

The sheet S moving downstream in the sheet feeding path 203 stops moving when the leading end of the sheet strikes the nip of the registration roller pair 205 in the rotation stopped state and a predetermined amount of loop is formed. By forming this loop, the skew state of the sheet S is corrected.

The sheet S whose skew has been corrected has a photosensitive drum 206 rotating clockwise by a registration roller pair 205 which starts rotating at a predetermined timing.
It is sent to the transfer section between the transfer charger 207 and the transfer charger 207. Thus, the toner image on the photosensitive drum 206 is transferred to the sheet S passing through the transfer unit by the transfer charger 207.

On the photosensitive drum 206 rotating clockwise, a light image read by a document image reading optical system (not shown) is projected to form an electrostatic latent image. The electrostatic latent image is developed by a toner developing device (not shown).

The sheet S on which the toner image has been transferred after passing through the transfer section is sent to the fixing device 209 by the conveyor belt 208.

The sheet S that has reached the fixing device 209 passes through a fixing nip between the fixing roller 209a and the pressure roller 209b, and is carried out of the apparatus by a fixing discharge roller pair 209c. The unfixed toner image is heated and pressed to be fixed on the sheet surface.

In the one-sided copying mode, the sheet S having passed through the fixing nip and having undergone the fixing process is guided to a pair of discharge rollers 211 by a flapper 210 and discharged to a discharge tray 212 outside the apparatus by the pair of discharge rollers 111. .

In the double-sided copying mode, the sheet S (the front-side copied sheet) having passed through the fixing nip and having been subjected to the fixing process is guided to the two-sided path 213 by the flapper 210, and is sequentially conveyed to the conveying roller pairs 214a to 214e to be conveyed on the same side. The path 213 moves downstream.

The sheet S, which has moved along the double-sided path 213, has a U
The user turns and enters the sheet reversing unit 215 communicating with the sheet feeding path 203. The sheet S is a pair of reversing rollers 216.
It is sent by. The reversing roller pair 216 is a sheet detection sensor 21 installed in the U-turn section 213a.
After a lapse of a predetermined time from when the sheet 7 detects the rear end of the sheet, the rotation is stopped. At this point, the rear end of the sheet has completely passed through the U-turn portion 213a, and
6.

The reversing roller pair 216 that has stopped rotating reverses immediately or after stopping for a certain period of time. Thus, the sheet S is re-fed from the sheet reversing unit 215.

The re-fed sheet S enters the sheet feeding path 203, is conveyed to a pair of conveying rollers 204d, and reaches a pair of registration rollers 205 in a rotation stopped state. And
The skew state of the sheet S is corrected by the registration roller pair 205 as described above.

The sheet S whose skew has been corrected is sent to the transfer section by the registration roller pair 205 which starts rotating at a predetermined timing. Thus, the toner image on the photosensitive drum 206 is transferred to the unprocessed surface (back surface) of the sheet S passing through the transfer unit by the transfer charger 207.

The sheet S on which the toner image has been transferred (the back side has been copied) has passed through the transfer section and is sent to a fixing device 209 to be subjected to a fixing process. It is discharged onto 212.

In the present image forming apparatus, the sheet S re-fed by the pair of reversing rollers 216 is corrected for lateral displacement. The reversing roller pair 216 is used for correcting the lateral displacement.

FIG. 2 shows a configuration of a lateral deviation correcting mechanism 220 (lateral deviation correcting means A) using the pair of reversing rollers 216.

The reversing roller pair 216 moves in the directions indicated by arrows X1 and X2 (a direction orthogonal to the sheet conveying direction) while holding the sheet S, and corrects the lateral displacement of the sheet S. The correction of the lateral displacement is performed based on the detection state of the reference position setting sensor 230.

A reversing motor 221 is connected (directly connected) to the lower roller (drive roller) 216a of the reversing roller pair 216. The reversing motor 221 is fixed on a movable base 222 movable in the directions of the arrows X1 and X2. When the movable base 222 is moved in the directions of the arrows X1 and X2, a pair of reversing rollers 216 is formed.
Roller 216a and upper roller (driven roller) 216b
Move together.

The movable base 222 is moved in the directions of arrows X1 and X2 by driving the lateral displacement correcting motor 223. The lateral displacement correcting motor 223 is driven by a motor gear 224, an idler gear 225 meshing with the motor gear 224, and a movable base 222 provided integrally on the axis of the idler gear 225.
Gear 226 meshing with a rack gear (not shown)
Is transmitted to the movable base 222 via the.

For example, when the lateral displacement correcting motor 223 is driven in the clockwise direction (arrow direction), the movable base 222 moves in the direction of the arrow X1, and when the lateral displacement correcting motor 223 is driven in the counterclockwise direction, the movable base 222 is moved. Moves in the direction of arrow X2.

The reference position setting sensor 230 is for setting the original transport reference position of the sheet. The sensor 230 is a photo interrupter, and outputs an ON signal when detecting a side edge of the sheet S in the width direction.

The reference position setting sensor 230 is fixed at a predetermined position of the path 215 in the case of the one-sided conveyance reference. In the case of the center conveyance reference, the sheet moves to a position corresponding to the sheet size (width size).

The information of the reference position setting sensor 230 is transmitted to the DC controller 231. DC controller 23
1 controls the driving of the lateral displacement correcting motor 223 based on this information.

Next, a method for correcting the lateral displacement of the sheet S will be described with reference to FIGS.

The correction of the lateral deviation of the sheet S is performed immediately after the reversing roller pair 216 starts reverse rotation. That is, when the pair of reverse rollers 216 starts reverse rotation, the detection state of the reference position setting sensor 230 is checked.

FIG. 3A shows a state in which the sheet S is laterally displaced to the back side of the path and the sensor 230 detects the lateral end Sa of the sheet S in the width direction.
Is detected and turned on.

In this case, the DC controller 231 drives the lateral displacement correcting motor 223 in the counterclockwise direction, so that the sheet side end Sa comes out of the sensor 230 and the sensor 230 is turned off (the position shown in FIG. 3B). Upside down roller pair 2
16 is moved in the direction of arrow X2. With this, sheet S
Is corrected, and the sheet S moves at the original transport reference position.

FIG. 4B shows a state in which the sheet S is laterally shifted to the front side of the pass, and the sensor 230 is not detecting the sheet side end Sa and is off.

In this case, the DC controller 231 first drives the lateral displacement correcting motor 223 in the clockwise direction until the sensor 230 detects the sheet side end Sa and turns on (the position shown in FIG. 4B). The reversing roller pair 216 is moved in the direction of arrow X1.

Next, the lateral displacement correcting motor 223 is driven in a counterclockwise direction to rotate the pair of reversing rollers until the sheet side end Sa comes out of the sensor 230 and the sensor 230 is turned off (the position shown in FIG. 4C). 216 is moved in the direction of arrow X2. Thus, the lateral displacement of the sheet S is corrected, and the sheet S
Moves at the original transport reference position.

In the case of the present image forming apparatus, the transport distance of the sheet S from the lateral displacement correcting position to the image forming position (transfer portion) is short (the two positions are close to each other), so that the lateral displacement amount at the image forming position is small. The lateral displacement correction accuracy can be increased. Sheet reversing unit 215
In addition to correcting the lateral displacement of the incoming sheet S, the lateral displacement of the sheet S re-fed from the sheet reversing unit 215 also shortens the transport distance of the sheet S.

Since the lateral displacement of the sheet S can be corrected while the sheet S is being conveyed, the throughput in the duplex mode can be increased.

The sheet reversing unit 215 is connected to the sheet cassette 20.
Since it does not exist on the rear end side of 0A to 200D, the width dimension (B) of the image forming apparatus main body does not increase.

<Second Embodiment> FIG. 5 shows a second embodiment of the present invention.
1 shows an overall schematic configuration of an image forming apparatus (copier) according to the embodiment.

The basic configuration of the present image forming apparatus is the same as that of the image forming apparatus shown in FIG. Therefore, here, the same members are denoted by the same reference numerals, and only structural differences will be described.

The sheet reversing unit 215 includes a lateral displacement correcting mechanism 242 (lateral displacement correcting unit B) for correcting the lateral displacement of the sheet S by moving the sheet S to the transport center, and a sheet reversing unit 215.
And a delivery roller pair 241 for delivering the sheet S from the printer.

The reversing roller pair 24 is connected to the sheet reversing unit 215.
At 0, the sheet S is fed. This reversing roller pair 240
After a lapse of a predetermined time from the time when the sheet detection sensor 217 detects the rear end of the sheet, the rotation is stopped. At this point, the rear end of the sheet has completely passed through the U-turn portion 213a and has not yet passed through the nip of the pair of feed rollers 241.

The lower roller (drive roller) 241b of the delivery roller pair 241 is a roller (half-moon roller) having a part of the outer periphery cut in a plane. This lower roller 241
When the sheet S is fed into the sheet reversing unit 215, the cut surface b is stopped with the cut surface facing the upper roller (driven roller) 241a (the state shown in the drawing), and is not ready to pinch the sheet S. . In this state, the lateral displacement correction by the lateral displacement correcting mechanism 242 is performed.

When the lateral deviation correction by the lateral deviation correcting mechanism 242 is completed, the lower roller 242b rotates clockwise,
The sheet S is nipped and sent out by the upper roller 241a and the lower roller 241b. This is sent to the sheet feeding path 203 by the conveying roller pair 243.

FIG. 6 shows an example of the configuration of the lateral displacement correcting mechanism 242.

Reference numerals 242-1 and 242-2 denote lateral displacement correcting members that come into contact with both side edges Sa and Sb in the width direction of the sheet S and move the sheet S to the conveyance center.

Reference numeral 242-3 denotes a lateral displacement correction motor. The motor 242-3 is driven by a motor gear 242-.
4 are transmitted to the rack gears 242-5 and 242-6 of the lateral shift correcting members 242-1 and 242-2.

For example, at the time of correcting the lateral displacement, the motor 242-
3 is driven in a counterclockwise direction (arrow direction). By doing so, the lateral shift correcting members 242-1 and 242-2 move in the direction of the arrow Y1, and bring the sheet S to the transport center. After correcting the lateral displacement, the motor 242-3 is driven clockwise. By doing so, the lateral shift correcting members 242-1 and 242-2 move in the arrow Y2 direction and return to the predetermined standby position.

Reference numeral 250 in FIG. 6 denotes a delivery motor. The drive of the delivery motor 250 is performed by a gear 251,
The lower roller 24 of the feed roller pair 241 through the roller 252
1b.

In the case of the present image forming apparatus, the first embodiment is used.
As in the image forming apparatus described above, the accuracy of correcting the lateral deviation is improved, the width dimension (B) of the image forming apparatus main body is not increased, and a mechanism for releasing the sheet sandwiching state required at the time of correcting the lateral deviation becomes unnecessary.

[0080]

As described above, according to the present invention,
Since the sheet reversing section of the two-sided pass is arranged horizontally on the downstream side of the path, the width dimension of the image forming apparatus main body does not increase due to the sheet reversing section. Also, since the lateral reversal with respect to the sheet in the double-sided image forming mode is corrected in the sheet reversing unit near the image forming position, the lateral deviation amount at the image forming position can be suppressed to a small value, and the lateral deviation can be corrected with high accuracy.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an overall schematic configuration of an image forming apparatus (copier) according to a first embodiment of the present invention.

FIG. 2 is a perspective view showing a configuration of a lateral displacement correcting mechanism provided in a two-sided path of the image forming apparatus of FIG.

FIG. 3 is a plan view illustrating a method for correcting a lateral displacement.

FIG. 4 is a plan view illustrating a method for correcting a lateral displacement.

FIG. 5 is a sectional view showing an overall schematic configuration of an image forming apparatus (copier) according to a second embodiment of the present invention.

FIG. 6 is a plan view illustrating a configuration of a lateral displacement correcting mechanism provided in a two-sided path of the image forming apparatus of FIG. 5;

FIG. 7 is a cross-sectional view (FIG. 7A) showing an overall schematic configuration of a conventional image forming apparatus and a perspective view showing a schematic configuration of a lateral shift correcting device provided in a two-sided path of the image forming apparatus. (FIG. 7 (b)).

[Explanation of symbols]

200A, 200B, 200C, 200D Paper cassette (paper supply section) 203 Paper supply path 206 Photosensitive drum (image forming section) 207 Transfer charger (image forming section) 213 Double-sided path 215 Sheet reversing section 216 Reversing roller pair 220 Correction of lateral misalignment Mechanism (lateral deviation correcting means A) 240 Reverse roller pair 241 Delivery roller pair 242 Lateral deviation correcting mechanism (lateral deviation correcting means B) S sheet

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI G03G 15/00 518 G03G 15/00 518

Claims (8)

[Claims] An image-formed sheet on the first side which has been fed from the sheet feeding section and once passed through the image forming section is returned to the image forming section via a double-sided path in order to form an image on the second side. In the image forming apparatus to be conveyed, the sheet reversing section in the two-sided pass is arranged horizontally on the downstream side of the path, and the sheet reversing section corrects a lateral shift of the sheet. 2. The image forming apparatus according to claim 1, wherein the sheet is reversed in a substantially horizontal posture in the sheet reversing unit. 3. The sheet inverted by the sheet inverting unit,
The image forming apparatus according to claim 1, wherein the sheet fed from the sheet feeding unit is sent to a sheet feeding path that guides the sheet to the image forming unit. 4. A lateral deviation correcting means A for correcting a lateral deviation of a sheet by moving in a direction intersecting a sheet conveying direction while holding the front and back surfaces of the sheet in a state where the sheet is reversed.
Is installed.
3. The image forming apparatus according to claim 1, wherein 5. A sheet is sent to the sheet reversing section,
5. The image forming apparatus according to claim 4, further comprising a pair of reversing rollers for feeding a sheet from the sheet reversing unit, wherein the pair of reversing rollers is used as the lateral deviation correcting unit. 6. A lateral deviation correcting means B for correcting the lateral deviation of the sheet by bringing the sheet to the center of conveyance in the sheet reversing section.
Is installed.
3. The image forming apparatus according to claim 1, wherein 7. The image forming apparatus according to claim 6, further comprising a pair of reversing rollers for feeding a sheet to the sheet reversing unit and a pair of sending rollers for sending a sheet from the sheet reversing unit.
An image forming apparatus according to claim 1. 8. One of the rollers of the delivery roller pair is a roller having a part of the outer circumference cut in a plane, and the delivery roller pair is capable of correcting the lateral displacement by the lateral displacement correcting means B in a state of not holding the sheet. The image forming apparatus according to claim 7, wherein the image forming is performed.