JP2002308503A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device capable of preventing occurrence of a jam even when control is conducted between small sheets. SOLUTION: A feeding path switch means 56 feeds sheets S1 and S2 to a predetermined sheet feeding path 46 or another sheet feeding path 45. When the sheets S1 and S2 are fed to the prescribed sheet feeding path 46 or the other sheet feeding path 45 along the feeding path switch means 56 displaced to a first or a second position, a sheet feeding direction upstream side end part of a guide surface 61 of the feeding path switch means 56, to which the sheets S1 and S2 are abutted, is bent to a direction apart from the sheets S1 and S2. Even when the following sheet S2 reaches the feeding path switch means 56 before the previous sheet S1 passes the feeding path switch means 56, therefore, the following sheet S2 is prevented from being caught by the sheet feeding direction upperstream side end part of the guide surface 61.

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, and more particularly, to a transport path switching unit for switching a sheet transport path.

[0002]

2. Description of the Related Art In a conventional image forming apparatus such as a copying machine or a printer, an image is formed on a sheet in an image forming section, and then the sheet is discharged to a paper discharge section.
For example, when a sheet on which an image is formed is to be discharged upside down, the sheet is turned over and discharged at a sheet reversing unit.

In order to reverse the sheet, a sheet reversing section is provided with a conveyance path switching means such as a flapper for switching the sheet conveyance path, and the sheet conveyance path is switched by the conveyance path switching means. Thus, the sheet is directed to the reversing path.

The transfer path switching means is generally driven by a solenoid, and switches the transfer path by excitation and non-excitation. However, when a solenoid is used, not only a space for the solenoid is required, but also the structure becomes complicated. Therefore, in the sheet reversing section, the flapper (sheet conveying path switching means) is switched using a spring. There is something that I did.

FIG. 18 shows the structure of a sheet reversing section of such a conventional image forming apparatus. In this image forming apparatus, a sheet conveyed in the direction of arrow B is conveyed by conveying rollers 165. Due to the stiffness (rigidity), the flapper 22 moves while pushing up the flapper 22 urged in the direction of arrow A by a spring (not shown).

The sheet moving while pushing up the flapper 22 is discharged by the discharge roller 161 and is stacked on a discharge tray (not shown). When the sheet passes through the flapper 22, the spring returns the flapper 22 to the standby position again.

On the other hand, when a sheet is inverted and discharged,
After the trailing edge of the sheet has passed through the flapper 22, the discharge rollers 1
By reversing 61, the sheet is directed to another discharge roller 163 along the upper end of the flapper 22 that has returned to the original position, as shown in FIG. The sheet is discharged and stacked on a discharge tray (not shown) in an inverted state.

[0008]

In the image forming apparatus having such a sheet reversing section, the upstream end (hereinafter referred to as the leading end) 22a of the flapper 22 in the sheet conveying direction is not pushed up by the sheet. In the standby state, the sheet is retracted out of the sheet discharge path R so that the leading end of the sheet is not caught.

However, when the leading end portion 22a is retracted outside the paper discharge path R as described above, when the flapper 22 is pushed up by the sheet S1, the leading end portion 22a moves in the paper discharge path as shown in FIG. Jump out.

When the leading end portion 22a protrudes into the sheet discharge path, the next sheet S2 moves while the previous sheet S1 moves along the flapper 22 as shown in FIG. When the sheet reaches the flapper 22, the leading end of the next sheet S2 may be caught by the protruding leading end portion 22a to cause a jam.

In order to prevent the occurrence of such a jam, the next sheet S2 may be prevented from reaching the flapper 22 while the previous sheet S1 is moving along the flapper 22. In this case, the interval between the sheets is widened, and it becomes impossible to perform the small sheet interval control.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and has as its object to provide an image forming apparatus which does not cause a jam even when the sheet interval control is performed. is there.

[0013]

According to the present invention, there is provided an image forming apparatus provided with an image forming section for forming an image on a sheet.
A plurality of sheet conveying paths for conveying the sheet, a first position for moving the sheet to a predetermined sheet conveying path among the plurality of sheet conveying paths, and a second position for moving the sheet to another sheet conveying path When the sheet is directed to the predetermined sheet conveyance path or another sheet conveyance path along the conveyance path switching means displaced to the first or second position. The upstream end of the guide surface of the transport path switching means with which the sheet comes into contact in the sheet transport direction is bent in a direction away from the sheet.

Further, according to the present invention, the transport path switching means includes:
A sheet is positioned at the first position to direct the sheet to the predetermined transport path, and the sheet inverted after passing through the transport path switching unit is displaced to the second position to direct the sheet to the other sheet transport path. It is characterized by having been done.

Further, according to the present invention, the transport path switching means includes:
It is characterized by being held at the second position by an urging member and being displaced to the first position by being pressed by the sheet.

Further, the invention is characterized in that the length of the guide surface of the transport path switching means is longer than the distance between the sheets when the sheets are continuously transported.

[0017]

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

FIG. 1 is a perspective view of an image forming apparatus according to an embodiment of the present invention, FIG. 2 is a perspective view of the image forming apparatus viewed from another direction, and FIG. 3 shows a schematic configuration of the image forming apparatus. FIG.

In FIG. 1 to FIG. 3, reference numeral 100 denotes an image forming apparatus.
An optional paper feed cassette 103 mounted as an option below the apparatus main body 101, a pressure plate 104 mounted on the upper surface of the apparatus main body 101, or an automatic document feeder (optionally mounted on the upper surface of the apparatus main body 101) ADF 102). In addition,
1 and 2 show a state where the pressure plate 104 is mounted on the upper surface of the apparatus main body 101, and FIG. 3 shows a state where the ADF 102 is mounted on the upper surface of the apparatus main body 101.

The image forming apparatus 100 has a function of a copier and a function of a facsimile, and converts image information (optical signal) of a read document into an electric signal to form an image. It is a multifunction machine.

An image forming section 1 is provided at a substantially central portion of the apparatus main body 101, a sheet feeding section 2 is provided below the image forming section 1, and a scanner section 3 which is an image reading section is provided at an uppermost portion. Note that the apparatus main body 101 according to the present embodiment is
Utilizes the characteristics of a digital machine to separate the image forming unit 1 and the scanner unit 3 and to form a wingless system by forming a paper discharge space 4 with an open side between them, and protrudes to the side of the apparatus. This realizes a space-saving image forming apparatus without the need.

Here, the image forming unit 1 is configured as a well-known electrophotographic print engine, and includes an electrophotographic process unit 150, a fixing device 151, a laser writing device (not shown), and the like.

The paper supply unit 2 includes a two-stage paper supply cassette 2.
The sheet stored in the sheet cassette 21 or the optional sheet cassette 103 is fed to the image forming section 1. Each paper cassette 2
Reference numerals 1 and 103 denote front-loading type drawers which are pulled out to the front side of the apparatus and replenish sheets, and a pull-out handle is provided at the center of the front surface of the cassette.

The scanner section 3 has a contact glass (not shown) disposed on the upper surface thereof, and a scanner unit (not shown) disposed below the contact glass.

The paper discharge space 4 has two sides except the front and right sides, that is, the left side and the back side in FIG. 3 are surrounded by a wall surface, and the scanner unit 3 and the image forming unit 1 surround the upper and lower sides. Have been. Further, the paper discharge space 4 includes a first paper discharge tray 41 provided on the upper surface of the image forming unit 1 and a second paper discharge tray 42 provided at the center of the paper discharge space 4.

The ADF 102 is mounted on an upper portion of the apparatus main body 101 by a hinge (not shown) provided on the back side of the apparatus.
It is installed so as to cover the contact glass on the upper surface of the scanner unit 3 so that it can be opened and closed and closed.

Here, the configuration and operation of the ADF 102 are the same as those of the conventional ADF, and a detailed description thereof will be omitted. However, when a document bundle (not shown) is set on the document table 71,
The originals are conveyed one by one from below onto the contact glass. After the scanning by the scanner unit 3 is completed, the originals are discharged onto the original discharge table 72.

The ADF 102 can be used as a pressure plate for copying that does not rely on automatic paper feeding, or for copying a book or notebook. When the optional ADF 102 is not mounted, a pressure plate 104 for pressing a document on the contact glass is mounted on the upper surface of the scanner unit 3 as shown in FIGS.

On the other hand, reference numeral 43 denotes a third discharge tray which is a second discharge portion provided on the left outer side of the apparatus main body 101 at a position opposed to the discharge space 4, and reference numeral 44 denotes a side wall of the discharge space 4. This is an optional paper discharge unit to be formed. Here, the optional discharge unit 44 includes, for example, a copy, a printer,
This unit is capable of performing FAX sorting, and in a case where sorting is required, the apparatus main body 1
01 is detachably mounted.

By providing such an optional sheet discharging unit 44 and stacking, for example, FAX sheets on the third sheet discharging tray 43, the total number of sheets to be stacked in the image forming apparatus 100 can be increased. Then, the sheets can be sorted and stacked.

As shown in FIG. 4, the optional discharge unit includes a main body 44A, a second discharge roller 52 as a first discharge unit, a third discharge roller 53 as a second discharge unit, It has three rollers of a vertical path roller 54. Note that the vertical path roller 54 and the second paper discharge roller 52
The third discharge roller 53 is driven by a different motor.

The optional paper discharge unit 44
Represents a first flapper 55 and a second
A flapper 56 is provided. Here, the first flapper 55
Is rotatable in the direction of arrow G by a solenoid 57 shown in FIG. The second flapper 56 is urged in a direction indicated by an arrow H by a spring (not shown). When the second flapper 56 is pushed up by a sheet, the second flapper 56 can rotate in a direction indicated by an arrow F against a spring force.

Further, inside the optional sheet discharging unit, a first sheet conveying path for discharging sheets to a second sheet discharging tray 42 which is a first discharging portion provided on one side of the main body portion 44A is provided. A sheet discharge path 46 is provided, and when a sheet is discharged to the second discharge tray 42, the sheet is discharged onto the second discharge tray 42 by the second discharge roller 52 via the sheet discharge path 46. ing.

When a third discharge tray 43 provided on the other side of the main body portion 44A is attached to the optional discharge unit 44, sheets are transferred to the third discharge tray 4
An optional discharge path 45, which is a second sheet conveyance path for discharging the sheet to the third discharge tray 43, is provided when the sheet recorded by the image forming unit 1 is discharged to the third discharge tray 43. The paper is discharged onto the third paper discharge tray 43 through the paper discharge tray 45.

FIG. 6 is a sectional view showing a paper discharge portion when the optional paper discharge unit 44 is mounted on the apparatus main body 101. Here, in the normal state, the sheet conveyed from the direction of arrow C passes through the first conveyance path 47 formed by the first flapper 55 located at the position indicated by the solid line, and is fed by the first paper discharge roller 51 in the direction of arrow I. And is stacked on the paper discharge tray 41.

In order to sort the sheets, for example, when discharging the sheets onto the second discharge tray 42, the first
The flapper 55 is rotated to the position shown by the broken line. As a result, the sheet conveyed in the direction of arrow C passes through the first flapper 55, passes through the vertical path roller 54, and pushes up the second flapper 56 by stiffening (rigidity) the sheet.
The second flapper 56 is moved to the sheet discharge path 46
The sheet is conveyed to the sheet discharge path 46 while being displaced to a first position indicated by a broken line toward the sheet discharge path 46. Thereafter, the sheet is discharged in the direction of arrow D by the second discharge roller 52 rotating in the direction indicated by the arrow, and is stacked on the second discharge tray 42.

When the sheets are discharged onto the third discharge tray 43 to sort the sheets, the sheets are first transferred to the vertical path rollers 54 in the same manner as when the sheets are discharged onto the second discharge tray 42. , The sheet is conveyed to the sheet discharge path 46 while pushing up the second flapper 56.

Next, when the trailing edge of the sheet passes through the second flapper 56 and is detected by a sensor (not shown), the second discharge roller 52 starts reverse rotation and the third discharge roller 5
The drive is transmitted to 3. When the trailing end of the sheet passes through the second flapper 56, the second flapper 56 is displaced (returned and rotated) to a second position indicated by a solid line for directing the sheet to the optional discharge path 45 by a spring. As a result, the sheet is conveyed to the optional discharge path 45 via the second flapper 56, discharged in the direction of arrow E, and stacked on the third discharge tray 43.

FIG. 7 is a view showing the shape of the second flapper 56. In FIG. 7, reference numerals 61 and 61a denote sheets passing along the second flapper 56 in a sheet discharge path 46 which is a predetermined sheet conveying path or other sheets. The sheet is a guide surface with which the sheet abuts when heading toward the optional discharge path 45 which is the sheet conveyance path.

The sheet 56a is the second flapper 56.
Is a leading end that is the upstream end in the sheet conveying direction of the guide surface 61 that first comes into contact with the guide surface 61 when the guide surface 61 contacts the guide surface 61 in a direction away from the sheet by a predetermined angle θ with respect to the guide surface 61. Bent. Here, in the present embodiment, the predetermined angle θ is set to 21 °. The angle θ is set in consideration of an angle α formed between a sheet conveyance direction C described later and the leading end 56a of the second flapper 22.

FIG. 8 is a view showing a state in which the second flapper 56 is in a standby state, that is, a state in which the second flapper 56 is in the second position. The 56 guide surface 61 and a direction of an arrow C which is a sheet conveyance direction form a predetermined angle β. Here, the angle β is such that when the sheet is conveyed, the second flapper 56 can be surely pushed up, and at the same time, β ≦ 30 ° is satisfied so that the sheet is not jammed by the second flapper 56. It has become. In the present embodiment, β is set to 15 °.

FIG. 9 is a view showing a state where the second flapper 56 is being pushed up by the sheet, that is, a state where the second flapper 56 is at the first position. At this time, the leading end 56a of the second flapper 22 approaches the sheet conveying path 62. In this state, the sheet conveying direction C and the leading end 56a of the second flapper 22 form an angle α.

Here, as in the case of the angle .beta. Shown in FIG. 8, the angle .alpha..ltoreq.30 so that the sheet is not caught on the second flapper 56 and jam occurs when the sheet is conveyed.
° is satisfied. In the present embodiment, α is set to 25 °.

That is, the tip 56a of the second flapper 56
Is an angle θ such that when the second flapper 56 is at the first position, the angle α formed with the sheet conveying direction C is ≦ 30 °.
(See FIG. 7). By bending the leading end 56a of the second flapper 56 at such an angle θ, the next sheet reaches the second flapper 56 before the previous sheet passes through the second flapper 56, Even if the portion 56a protrudes, the next sheet can be prevented from being caught on the leading end portion 56a.

In FIG. 9, m is the second flapper 5
Reference numeral 6 denotes the distance between the leading end portion 56a and the sheet when in the first position. In the present embodiment, the distance m is set to approximately m = 5 (mm). However, the longer the distance m is, the more the sheet can be prevented from being caught on the leading end portion 56a.

Next, the image forming apparatus 10 having such a configuration will be described.
The copying operation at 0 and the actual movement of the sheet at the paper discharge unit will be described by taking as an example the case where the ADF 102 is used as a pressure plate.

First, in FIG. 3, an original is placed on a contact glass (not shown) on
After closing the button 102, the number of copies and the like are specified by the operation unit 60 (see FIG. 2), and the start button is pressed. Thus, the reading of the document by the scanner unit is started, and the image information of the read document is digitized by photoelectric conversion and subjected to image processing.

Then, the laser writing device of the image forming section 1 is driven based on the processed signal, and an electrostatic latent image is formed on the photosensitive drum. Thereafter, the latent image is visualized as a toner image, and is transferred to the sheet cassette 21 fed by the sheet feeding unit 2 or a sheet of the sheet feeding table 103. After that, the toner image transferred onto the sheet is fixed by the fixing device 151 and sent to the paper discharge unit 4.

When the sheets are stacked on the sheet discharge tray 41, the driving of the main body vertical path roller 57 is started after a predetermined time as shown in FIG. 10 after the sheets are conveyed to the fixing device 151. Thus, the sheet conveyed in the direction of arrow C passes through the first conveyance path 47 formed by the first flapper 55 located at the position indicated by the solid line, and is discharged from the first paper discharge roller 51, and is discharged from the paper discharge tray. 41.

For sorting, a second paper output tray 42 is provided.
When discharging the sheet upward, first, the first flapper 55
Is rotated to move it to the position shown in FIG. Thus, the conveyed sheet S <b> 1 passes through the first flapper 55 and goes to the vertical path roller 54.

After passing through the vertical path roller 54 as shown in FIG. 12, the sheet S1 is conveyed to the sheet discharge path 46 while pushing up the second flapper 56 by stiffness (rigidity). The paper is discharged by the second paper discharge roller 52 that rotates and is stacked on the second paper discharge tray 42.

On the other hand, for sorting, the third paper discharge tray 42
When the sheet S1 is discharged upward, the sheet S1 passes through the vertical path roller 54 as shown in the figure, and is conveyed to the sheet discharge path 46 while pushing up the second flapper 56 by the straining (rigidity) of the sheet S1. When the rear end of S1 passes through the fixing device 151, the conveyance speed of the sheet S1 is increased by 2.5 times after a predetermined time, and at the same time, the driving of the second discharge roller 52 is started.

As a result, as shown in FIG.
1 is partially discharged in the direction of arrow D by the second discharge roller 52 rotating in the direction indicated by the arrow. Thereafter, when the rear end of the sheet S1 conveyed by the second discharge roller 52 passes through the second flapper 56, the second flapper 56 is returned to the original standby position by a spring (not shown) as shown in FIG. Return to

Next, when the reverse sensor 58 detects the rear end of the sheet S1 that has passed through the second flapper 56,
The driving of the second paper discharge roller 52 stops, and after a predetermined time, the second
The discharge roller 52 starts rotating in the reverse direction.

At the same time, the driving of the third discharge roller 53 is started, as shown in FIG. 15, whereby the sheet S1 is conveyed to the optional discharge path 45. At this time, the transport speed of the second discharge roller 52 and the third discharge roller 53 is a speed increased by 2.5 times.
Here, when the sheets are stacked on the third discharge tray 43 as described above, the speed increase control is performed as described above, so that the second
It is possible to prevent the collision of the sheet at the time of sheet reversal near the flapper 56.

Then, the second discharge roller 52 and the third
The sheet S1 is conveyed in the direction of the arrow E by the rotation of the discharge roller 53, and then, as shown in FIG.
3 is loaded face down. By repeating such an operation, the sheets are sequentially stacked on the third discharge tray 43 in page order.

The guide surface 6 of the second flapper 56
The length y of 1 (see FIG. 7) is longer than the distance x between the two sheets S1 and S2 shown in FIG. 13, for example.
Therefore, for example, as shown in FIG.
When the trailing end of the sheet S3 is still moving along the second flapper 56, the leading end of the next sheet S3 already reaches the leading end 56a of the second flapper 22.

However, even in such a case, by bending the leading end 56a of the second flapper 22 in a direction away from the sheet S3, the next sheet S3 can be prevented from being caught by the leading end 56a. . Thus, after this, the next sheet S3 is conveyed while pushing up the second flapper 56, and then discharged without causing a jam.

The reliability of the image forming apparatus itself can be improved by enabling the sheet to be discharged without causing a jam. Further, when the rear end of the previous sheet S2 is still moving along the second flapper 56, the front end of the next sheet S3 can reach the front end 56a of the second flapper 22. Therefore, it is possible to reduce the interval between sheets, and thereby, it is possible to perform small sheet interval control without causing a jam.

In the above description, a case has been described in which the third discharge tray 43 for sorting is provided in the apparatus main body 101 as the second discharge portion. However, the present invention is not limited to this. As shown in FIG. 17, a post-processing device 48 for performing post-processing such as binding processing may be mounted on the sheet on which an image has been formed as shown in FIG. 17 instead of the third discharge tray 43.

Although the structure of the paper discharge portion provided in the image forming apparatus has been described above, the present invention is not limited to this, and is applicable to, for example, a reversing unit for forming an image on both sides of a sheet. Of course you can.

Further, the case where the lower end portion 56a of the second flapper 22 is bent as shown in FIG. 7 has been described so far, but if necessary, the sheet may be conveyed to another guide surface 61a shown in FIG. The end on the upstream side in the direction may also be bent in a direction away from the sheet.

In the above description, an image forming apparatus having two sheet conveyance paths, the optional discharge path 45 and the sheet discharge path 46, has been described as a sheet conveyance path. Naturally, the present invention can be applied to an image forming apparatus having a sheet conveying path.

[0064]

As described above, according to the present invention, when a sheet is directed to a predetermined sheet transport path or another sheet transport path, the guide surface of the transport path switching means with which the sheet comes into contact is located upstream of the guide surface in the sheet transport direction. By bending the end portion in a direction away from the sheet, even if the next sheet arrives at the conveyance path switching means before the previous sheet passes through the conveyance path switching means, the next sheet is a sheet on the guide surface. It can be prevented from being caught on the upstream end in the transport direction. Thus, it is possible to prevent a jam from occurring even when the small sheet interval control is performed.

[Brief description of the drawings]

FIG. 1 is a perspective view of an image forming apparatus according to an embodiment of the present invention.

FIG. 2 is a perspective view of the image forming apparatus viewed from another direction.

FIG. 3 is a diagram illustrating a schematic configuration of the image forming apparatus.

FIG. 4 is a cross-sectional view of an optional sheet discharge unit provided in the image forming apparatus.

FIG. 5 is a perspective view of the optional sheet discharging unit.

FIG. 6 is a cross-sectional view illustrating a paper discharge portion when the optional paper discharge unit is mounted on the apparatus main body.

FIG. 7 shows a second example provided in the optional sheet discharging unit.
The figure which shows the shape of a flapper.

FIG. 8 is a diagram showing a state when the second flapper is in a standby state.

FIG. 9 is a diagram showing a state when the second flapper is pushed up by a sheet.

FIG. 10 is a diagram illustrating a state in which driving of a main body vertical pass roller provided in the optional sheet discharging unit is started.

FIG. 11 is a first diagram illustrating a state in which a sheet is discharged to a second discharge tray provided in the image forming apparatus of the optional discharge unit.

FIG. 12 is a second diagram illustrating a state where a sheet is discharged to a second discharge tray of the optional discharge unit.

FIG. 13 is a first diagram illustrating a state where a sheet is discharged to a third discharge tray of the optional discharge unit.

FIG. 14 is a second diagram illustrating a state in which a sheet is discharged to a third discharge tray of the optional discharge unit.

FIG. 15 is a third diagram illustrating a state where a sheet is discharged to a third discharge tray of the optional discharge unit.

FIG. 16 is a fourth diagram illustrating a state in which a sheet is discharged to a third discharge tray of the optional discharge unit.

FIG. 17 is a diagram illustrating a configuration of an image forming apparatus according to another embodiment of the present invention.

FIG. 18 is a diagram illustrating a configuration of a sheet reversing unit of a conventional image forming apparatus.

FIG. 19 is a diagram illustrating a state where a flapper provided in the sheet reversing section is pushed up by a sheet.

FIG. 20 is a diagram showing a state in which the next sheet arrives at the flapper while the previous sheet is moving along the flapper.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 image forming unit 2 paper feed unit 4 paper discharge space 41 first paper discharge tray 42 second paper discharge tray 43 third paper discharge tray 44 optional paper discharge unit 45 optional discharge path 46 sheet discharge path 48 post-processing device 51 first Discharge roller 52 Second discharge roller 53 Third discharge roller 55 First flapper 56 Second flapper 100 Image forming apparatus 101 Main body of the apparatus

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H072 AB14 CA01 CB01 CB06 FA01 JA04 3F053 EA02 EA05 EC02 EC05 LA02 LA07 LB03 3F101 FA01 FB11 FC11 FE02 FE19 LA02 LA07 LB03

Claims (4)

[Claims] 1. An image forming apparatus having an image forming unit for forming an image on a sheet, wherein a plurality of sheet transport paths for transporting the sheet, and a predetermined sheet transport of the sheet among the plurality of sheet transport paths. A first position for moving the sheet toward a path, and conveying path switching means capable of displacing the sheet to a second position for moving the sheet to another sheet conveying path, wherein the conveying path is switched to the first or second position. When the sheet travels along the means to the predetermined sheet transport path or another sheet transport path, the sheet transport direction upstream end of the guide surface of the transport path switching unit with which the sheet abuts is moved away from the sheet. An image forming apparatus characterized in that the image forming apparatus is bent to face. 2. The transport path switching unit according to claim 1, wherein the sheet is directed to the predetermined transport path at the first position, and the sheet reversed after passing through the transport path switching unit is displaced to the second position. The image forming apparatus according to claim 1, wherein the image forming apparatus is configured to be directed to the another sheet conveyance path. 3. The transport path switching means is held at the second position by an urging member, and is pressed by the sheet to be displaced to the first position. Or the image forming apparatus according to 2. 4. The apparatus according to claim 1, wherein a length of the guide surface of the transport path switching unit is longer than a distance between the sheets when the sheets are continuously transported. An image forming apparatus according to claim 1.