JP2000327201A - Carrying direction inverting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To miniaturize an image forming device and reduce costs by providing a carrying direction inverting means, and providing the means with functions of a front-and-rear changeover discharge mechanism for an image forming surface in a printed medium discharge device, a both-side printing mechanism for a printed medium, and a front-and-rear changeover discharge mechanism for an image forming surface in the image forming device. SOLUTION: This carrying direction inverting device 32 having a paper feed hole 31 corresponding to a lever 53 placed near a transporation route changeover lever 23 is provided in a paper discharge device 28 for an image forming device 1. A lever 33 for guiding paper 13 fed from the paper feed hole 31 to a transportation route 34 as a first route, a transporation route 38 through which the paper 13 is guided by the lever 33, and a lever 45 placed in a connecting part between carrying routes 34, 46 are provided in the carrying direction inverting device 32. A transporation route 37 for feeding the paper 13 from a top surface paper discharge tray 12 to the carrying direction inverting device 32 is placed between the lever 53 and a paper discharge roller 18. A transporation-direction inverting portion 41 having a lever 44 is provided near a transporation inlet 42.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for reversing the direction of conveyance of a recording medium in an image forming apparatus, and more particularly to a conveyance direction provided with a double-sided printing mechanism for a recording medium and a discharge mechanism for switching the image forming surface of the recording medium from front to back. It relates to a reversing device.

[0002]

2. Description of the Related Art Image forming apparatuses are often used in general copying machines, and in recent years, color image forming apparatuses have become widespread. Then, as an image forming apparatus capable of outputting a color image, a latent image formed on a photoconductor by a laser beam or the like is developed by a developing device of each color, and each color image formed on the photoconductor is temporarily transferred to an intermediate transfer member. There is conventionally known a so-called intermediate transfer body type in which a composite image on the intermediate transfer body is collectively transferred onto paper. FIG. 8 is an explanatory diagram showing the internal structure of a conventional color image forming apparatus and a two-sided printing apparatus.

In FIG. 8, a laser unit 2 having a laser oscillator, a polygon mirror or a lens built therein, a photosensitive drum 3 having a photoconductive layer on its surface, and a periphery of the photosensitive drum 3 are provided inside an image forming apparatus 1. And a developing device 4 for uniformly charging the peripheral surface thereof and a developing device 4 for developing an electrostatic latent image, and the developing device 4 is for developing the stored toner 19. A developing roller 5 is provided. The developing units 4 are yellow, magenta, cyan,
Four are provided so as to correspond to four colors of black.

An intermediate transfer belt 6 which is wound around a loop and travels is disposed below the four developing units 4.
The intermediate transfer belt 6 is a first belt disposed in the loop.
The transfer roller 7 contacts the photosensitive drum 3 to transfer the toner image. A second transfer roller 8 and the like are arranged outside the loop, and the peripheral surface thereof is brought into contact with the intermediate transfer body belt 6. Reference numeral 15 denotes a cleaning member, 9 denotes a fixing device, and 11 denotes a pickup roller.

A normal printing operation in the color image forming apparatus having the above configuration is as follows.

The paper 13 is supplied from a paper supply cassette 10 disposed on the bottom side of the image forming apparatus, and the paper 13 is held at a position where the end of the paper 13 is sandwiched between registration rollers 16 for transporting the paper 13. Stop. Laser unit 2
Emits light corresponding to the image signal to generate an electrostatic latent image on the photosensitive drum 3. First, development is performed by a yellow developing device 4 containing yellow toner. Next, the visible image on the photosensitive drum 3 is transferred to the intermediate transfer belt 6.
This is similarly performed for magenta, cyan, and black, and images of each color are superimposed on the intermediate transfer belt 6. Then, the sheet 13 is sent from the registration roller 16 at a proper timing so that the image on the intermediate transfer belt 6 is formed at an appropriate position on the sheet 13. While the paper 13 passes through the second transfer roller 8, a transfer bias is applied to transfer the toner on the intermediate transfer belt 6 onto the paper 13 to form a visible image. When the paper 13 passes through the fixing device 9, the toner is heated by the heating roller of the fixing device 9, the image is fixed on the paper 13, and is discharged from the discharge port 30 of the image forming apparatus 1 to the top surface discharge tray 12. And printing is completed. The above is the operation in the single-sided printing mode.

On the other hand, recent image forming apparatuses have a high demand for double-sided printing, and many products have a double-sided printing apparatus as an option. In an image forming apparatus having this double-sided printing device as an option, there is a transport direction reversing mechanism that can switch the transport direction of the paper, turn it over, and supply it again to the printing unit, instead of directly discharging the paper on which an image is formed on one side, It has a function to discharge paper after printing on both sides. Such a two-sided printing mode will be described with reference to FIG.

In one-sided image formation, the sheet 13 on which the image is fixed by the heating roller of the fixing unit 9 is conveyed to the sheet discharge port 30 of the image forming apparatus 1 as in the one-sided printing mode. Until the sheet 13 passes through a lever 17 arranged in the middle of the conveyance path, the operation is exactly the same as in the single-sided printing mode, and whether or not the sheet 13 has passed through the lever 17 is determined by a photo interrupter (not shown). Judge by detecting the edge.
When the rear end of the paper 13 passes through the lever 17, the transport roller 18 in the paper discharge port 30 of the image forming apparatus 1 stops rotating with the rear end of the paper 13 held therebetween. Next, lever 1
7 is a sheet 1 nipped by the transport roller 18 of the image forming apparatus 1
The sheet 13 is drawn into the image forming apparatus 1 again by rotating the transport roller 18 in the direction opposite to the direction in which the sheet is ejected to the sheet ejection tray 12 on the top surface, so that the sheet 13 is rotated. It is guided to a path extending to the printing device 22. The sheet 13 is conveyed in the double-sided printing device 22 and is conveyed again to the registration roller 16 by the conveyance rollers 20 and 21, and the sheet 13 stops at a position where the sheet end is sandwiched between the registration rollers 16. Thereafter, in the same manner as the operation in the single-sided printing mode, the image is transferred and fixed on the back surface of the sheet 13, discharged from the discharge port 30 of the image forming apparatus 1 to the top-side discharge tray 12, and the double-sided printing is completed. I do. The above is the operation in the duplex printing mode.

Further, when plain paper is used as paper, many products have a large-capacity paper discharge device for printing printed paper as an option because high-quality and high-speed printing is possible. As the sheet discharging device, there are devices called a stacker, a sorter, and a mailbox.

For example, in an image forming apparatus having a stacker as an option, in a face-up discharge mode, sheets discharged from the image forming apparatus are stacked as they are on a sheet discharge tray with the image printed side of the sheet facing up. On the other hand, in the face-down discharge mode, the conveyance direction of the discharge paper from the image forming apparatus is switched by the conveyance direction reversing mechanism in the stacker, and the paper is stacked on the paper discharge tray with the image print side down.

FIG. 9 is an explanatory view showing the internal structure of a conventional color image forming apparatus and a stacker. Note that the same components as those in the example of FIG. 8 are designated by the same reference numerals, and a detailed description thereof will be omitted.

In FIG. 9, a stacker type sheet discharging device 28 disposed on the side of the image forming apparatus 1 can receive the sheet 13 guided by a transport path switching lever 23 disposed in the image forming apparatus 1. It includes levers 24 and 25, a fixed bin tray 26, a movable bin tray 27, a transport roller 29, and the like. The operation of the face-up paper discharge mode to the fixed bin tray 26 of the paper discharge device 28 is as follows.

First, the printing operation of the image forming apparatus 1 is exactly the same as the one-sided printing mode described above until the image is fixed on the paper 13 by the heating roller of the fixing unit 9. When the paper 13 passes through the lever 23, the lever 2
Reference numeral 3 denotes a rotating posture for guiding the fixed sheet 13 to the sheet feeding port of the sheet discharging device 28 of the image forming apparatus 1. Therefore, the sheet 13 is transported to the sheet feeding port of the sheet discharging apparatus 28 of the image forming apparatus 1. . Then, the levers 24, 2 in the stacker 28
5 is set in a rotating posture for guiding the paper 13 to the fixed bin tray 26, the paper 13 loaded from the image forming apparatus 1 is set.
Is discharged to the fixed bin tray 26 with the surface on which the image is formed facing upward, and the operation is completed.

On the other hand, the operation of the face-down discharge mode of the paper discharge device 28 to the movable bin tray 27 is as follows.

As in the face-up paper discharge mode to the fixed bin tray 26, the paper 13 carried in from the image forming apparatus 1 is transported to the paper discharge port to the fixed bin tray 26 of the paper discharge device 28. Until the sheet passes through the lever 25, the operation is exactly the same as in the face-up discharge mode to the fixed bin tray 26. Whether the paper 13 has passed the lever 25 is determined by detecting the trailing end of the paper 13 with a photo interrupter. When the rear end of the paper 13 passes through the lever 25, the transport roller 29 of the paper discharge port of the paper discharge device 28 stops rotating while holding the rear end of the paper 13. Next, the sheet 1 held by the lever 25 between the transport rollers 29 of the sheet ejection port of the sheet ejection device 28
The paper 13 is drawn into the paper discharge device 28 again by the rotation of the transport roller 29 in the direction opposite to the direction in which the paper is discharged to the fixed bin tray 26. Guided to an extended path. Then, the sheet is discharged to the moving bin tray 27 with the surface on which the image is formed facing down, and the operation is completed.

[0016]

However, according to the specifications of the conventional image forming apparatus, the two-sided printing apparatus and the sheet discharging apparatus have the same positional relationship with respect to the same image forming apparatus, and are shown in FIGS. As described above, the two-sided printing device 22 and the paper discharge device 28 need to be installed on the same side of the image forming apparatus 1. Therefore, a useless space is created below the double-sided printing device, and the installation space is also increased.

Further, in order to separately provide the double-sided printing device and the sheet discharging device as options, each requires a transport direction reversing mechanism. In this case, if a two-sided printing device and a paper ejection device are installed in the image forming apparatus, the transport direction reversing mechanism will be provided at two locations as the whole system,
They tend to be expensive systems.

Further, the paper discharge to the image forming apparatus is limited to the face-down discharge mode in which the image forming surface is down.

Therefore, the present invention provides a face-up discharge mode function in which the entire system is inexpensive, the installation space is reduced, and the paper is discharged to the image forming apparatus side with the image forming surface up. The purpose is to do.

[0020]

A transport direction reversing device according to the present invention comprises a transport direction reversing section having a transport direction reversing means for a print medium, and a print medium on which an image is formed and discharged by an image forming section of an image forming apparatus. A first path for transporting the print medium to the transport direction reversing section, a second path for transporting the print medium on which an image has been formed by the transport direction reversing section to a print medium discharge device, and an image for transporting the image from the transport direction reversing section. A third path for re-transporting the print medium on which the image is formed to the image forming unit of the image forming apparatus, and discharging the print medium on which the image is formed by the image forming unit of the image forming apparatus to the print medium A fourth path for directly transporting the print medium to the apparatus, a first transport mode for transporting the print medium from the first path to the second path via the transport direction reversing unit, and the transport from the first path. Opposite direction The print medium on which an image is formed by the image forming unit of the image forming apparatus in the second transport mode for transporting the print medium to the third path via the unit and the fourth path, and discharges the print medium to the print medium. It is characterized by having a path switching means capable of taking a third conveyance mode for directly conveying the print medium, and a conveyance means for conveying the print medium.

In this configuration, the transport direction reversing unit at one place in the entire system includes a mechanism for switching the front and back of the image forming surface of the print medium in the print medium discharge device, and the print medium in the image forming apparatus. Is realized.

[0022]

According to the first, fourth, and seventh aspects of the present invention, each of the transport direction reversing units in the system as a whole includes a front side and a back side of an image forming surface of the print medium in the print medium discharge device. This has the function of realizing a switching and discharging mechanism and a double-sided printing mechanism for printing the print medium in the image forming apparatus.

According to a second aspect of the present invention, a double-sided printing mechanism for the printing medium in the image forming apparatus and an image forming apparatus for the printing medium in the image forming apparatus are provided in the transport direction reversing section at one location as a whole system. This has the function of realizing a front-back switching discharge mechanism.

According to the third, fifth and sixth aspects of the present invention, each of the transport direction reversing units is provided at one location as a whole system.
A mechanism for switching the front and back of the image forming surface of the print medium in the print medium discharging device, a mechanism for duplex printing of the print medium in the image forming apparatus, and a mechanism for switching the front and back of the image forming surface of the print medium in the image forming apparatus It has the effect of realizing a mechanism.

According to an eighth aspect of the present invention, a common option for the image forming apparatus and the print medium discharge device is provided by being located on an intermediate conveyance path between the image forming apparatus and the print medium discharge device. The mechanism has an effect that the mechanism can be attached to any of the image forming apparatus and the print medium discharging apparatus.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is an explanatory diagram showing an embodiment of the image forming apparatus system according to the third aspect of the present invention.
Note that the printing operation in the image forming apparatus and the paper transport operation in the paper discharging device are the same as those in the related art.
The same components as those in the example shown in FIG. 9 are designated by the same reference numerals, and detailed description thereof will be omitted.

In the paper discharge device 28 disposed on the left side of the image forming apparatus 1, a transport direction reversing device 3 having a paper feed port 31 opened corresponding to a lever 53 disposed near the lever 23 is provided.
2 is provided. Since the transport direction reversing device 32 is disposed between the image forming apparatus 1 and the sheet discharging device 28,
It can be provided on the image forming apparatus 1 side. A transport path 37 for feeding the paper 13 from the top surface paper discharge tray 12 to the transport direction reversing device 32 is disposed between the lever 53 and the paper discharge roller 18.

In the transport direction reversing device 32, a paper feed port 31 is provided.
A lever 33 that guides the paper 13 carried in from the conveyance path to a conveyance path 34 as a first path, conveyance rollers 35, 36, 43, and 48 arranged along the conveyance path 34, and the paper 13 carried in from the paper supply port 31 are provided. A transport path 38 as a fourth path guided by the lever 33, a transport roller 39 disposed along the transport path 38, a paper discharge port 40 from which the paper 13 is sent out by the transport roller 39, and an end of the transport path 38. The transfer roller 4 branches to the transfer path 34 side.
7 is provided, and a lever 45 is provided at a portion connected to the transfer paths 46 and 46. Reference numeral 41 denotes a transport direction reversing unit, and a paper detection sensor (not shown) is disposed near the carry-in port 42 of the transport direction reversing unit 41. A lever 44 is disposed near the carry-in port 42, and a separate transport path 49 is connected. Transport rollers 50 and 51 are disposed along the transport path 49, and a paper discharge port 52 is provided at the end of the path. .

In the above-described configuration, in the face-down discharge mode to the top surface discharge tray 12 of the image forming apparatus 1, as described in the background art, the lever 23 is connected to the fixing device 9 as described above.
Is set to a rotation posture for guiding the paper 13 passing through the paper discharge port 30 to the top surface paper discharge tray 12. As a result, the sheet 13 that has passed through the fixing unit 9 is discharged from the sheet discharge port 30 with the surface on which the image is formed facing down, and the printing operation is completed.

In the face-up paper discharge mode to the top paper discharge tray 12, the lever 23 is set in a rotating posture for guiding the paper 13 passing through the fixing device 9 to the paper feed port 31 of the transport direction reversing device 32. Is set to a rotation posture for guiding the paper 13 carried in from the paper feed port 31 to the transport path 34 as the first path. As a result, the sheet 13 that has passed through the fixing device 9 is carried into the transport path 34 of the transport direction reversing device 32 from the paper feed port 31 and transported in the direction of arrow F by the transport rollers 35 and 43. When a sheet detection sensor (not shown) provided near the paper feed port 31 of the conveyance path 34 detects the rear end of the conveyed sheet 13, the conveyance rollers 35 and 43 are separated from the sheet 13, and instead, are conveyed by the conveyance roller 36. , 48 hold the paper 13. The transport rollers 36 and 48 are rotated so as to transport the sheet on the transport path 34 in the B direction. Also, lever 5
Reference numeral 3 denotes a rotation posture for guiding the sheet 13 carried out from the conveyance direction reversing device 32 to the conveyance path 37. Thereby, paper 1
The sheet 3 is discharged again from the sheet feeding port 31 and is discharged from the sheet discharging port 30 of the image forming apparatus 1 via the transport path 37 with the image forming surface facing upward, and the printing operation is completed.

In the face-up paper discharge mode to the paper discharge device 28, the lever 23 moves the paper 13 passing through the fixing device 9.
Is set to a rotation posture for guiding the sheet 13 carried from the paper supply port 31 to the conveyance path 38 as a fourth path. . Thereby, the sheet 1 that has passed through the fixing device 9
3 is a conveyance path 3 of the conveyance direction reversing device 32 from the paper feed port 31.
8 and transported by transport rollers 39. As a result, the paper 13 is discharged from the paper discharge port 40 of the transport direction reversing device 32, discharged to the fixed bin tray 26 or the movable bin tray 27 of the paper discharge device 28 with the surface on which the image is formed facing up, and printed. Ends.

In the face-down paper discharge mode to the paper discharge device 28, the lever 23 moves the paper 13 passing through the fixing device 9.
Is set to a rotation posture for guiding the paper 13 carried in from the paper supply port 31 to the conveyance path 34. As a result, the sheet 13 that has passed through the fixing device 9 is carried into the carrying path 34 of the carrying direction reversing device 32 from the paper supply port 31, carried in the direction of arrow F by the carrying rollers 35 and 43, and carried into the carrying direction reversing unit 41. Is done. Carriage entrance 4 of conveyance direction reversing part 41
When the trailing end of the paper 13 carried into the transport direction reversing section 41 is detected by a paper detection sensor (not shown) provided near the transport roller 2, the transport roller 43 is separated from the paper 13 and is in a separated state instead. Transport rollers 48 hold the paper 13. The transport roller 48 is used for the sheet 13 of the transport direction reversing unit 41.
Is driven to rotate in the direction B. At this time, the levers 44 and 45 are in a rotating posture for guiding the sheet 13 carried out from the conveyance direction reversing unit 41 to a conveyance path 46 as a second path, and the sheet 13 is moved along the conveyance path 46 by the conveyance rollers 47 and 48. Conveyed. As a result, the paper 13 is discharged from the paper discharge port 40 of the transport direction reversing device 32 and is fixed to the fixed bin tray 26 or the movable bin tray 2 of the paper discharge device 28.
The sheet is discharged to the printer 7 with the surface on which the image is formed facing down, and the printing operation is completed.

In the double-sided printing mode in the image forming apparatus 1,
The lever 23 is set in a rotation posture for guiding the paper 13 passing through the fixing device 9 to the paper feed port 31 of the transport direction reversing device 32, and the lever 33 is configured to rotate the paper 13 carried from the paper feed port 31 to the transport path 34. The posture is set. The paper 13 that has passed through the fixing device 9 is carried into the transport path 34 of the transport direction reversing device 32 from the paper feed port 31, and is transported by transport rollers 35 and 43 to the arrow F.
And is carried into the carrying direction reversing unit 41. When the trailing end of the sheet 13 conveyed into the conveyance direction reversing unit 41 is detected by the sheet detection sensor near the carry-in port 42, the conveyance roller 43 is separated from the sheet 13 and is instead a separated conveyance roller. 48 holds the paper 13. The transport roller 48 rotates so as to transport the paper 13 of the transport direction reversing unit 41 in the B direction. Up to this point, the operation is the same as in the face-down sheet discharge mode to the sheet discharge device 28 described above, but the lever 44 rotates the sheet 13 conveyed from the conveyance direction reversing section 41 to the conveyance path 49 as a third path. Posture. Therefore, the transport rollers 48, 5
The paper 13 is transported along the transport path 49 by 0 and 51. As a result, the paper 13 is carried out of the paper discharge port 52 of the transport direction reversing device 32, and is again carried into the printing unit of the image forming apparatus 1 to perform double-side printing.

FIGS. 2 to 7 show embodiments of different configurations. In each of the drawings, the same components as those described in FIG. 1 are designated by the same reference numerals, and detailed description thereof will be omitted. .

FIG. 2 is an explanatory diagram showing an embodiment of the image forming apparatus system according to the first aspect of the present invention.

This embodiment is different from the image forming apparatus shown in FIG. 1 in that a mechanism for switching the front and back sides of the image forming surface of the sheet 13 is eliminated. Fig. 1 except for the up discharge mode
This is the same as the operation mode of the example.

FIG. 3 is an explanatory view showing an embodiment of the image forming apparatus system according to the second aspect of the present invention.

This embodiment is different from the paper discharge device 28 shown in FIG. 1 in that a mechanism for switching between the front and back sides of the image forming surface of the paper 13 in the paper discharge device 28 is omitted. Except for the face-down discharge mode to the discharge device 28, the operation modes are exactly the same as the operation modes described with reference to FIG.

FIG. 4 is an explanatory diagram showing one embodiment of the image forming apparatus system according to the fourth aspect of the present invention.

In this embodiment, the image forming apparatus shown in FIG. 1 has a mechanism for switching the front and back sides of the image forming surface of the sheet 13 and the sheet 13 on which an image is formed by the image forming section is directly conveyed to the sheet discharging apparatus 28. And a fourth route. The operation modes described with reference to FIG. 1 are exactly the same as the operation modes described with reference to FIG. 1 except for the face-up discharge mode for the top surface discharge tray 12 and the face-up discharge mode for the paper discharge device 28 of the image forming apparatus 1.

FIG. 5 is an explanatory view showing an embodiment of the image forming apparatus system according to the fifth aspect of the present invention.

This embodiment is different from the embodiment shown in FIG. 1 in that the fourth path for directly transporting the sheet 13 on which an image is formed by the image forming section of the image forming apparatus to the sheet discharging device 28 is omitted. Except for the face-up discharge mode to the apparatus 28, the operation mode is the same as the operation modes described with reference to FIG.

FIG. 6 is an explanatory view showing an embodiment of the image forming apparatus system according to the sixth aspect of the present invention.
In this example, the face-down discharge mode to the top surface discharge tray 12 of the image forming apparatus 1 and the image forming apparatus 1
The face-up paper discharge mode to the top surface paper discharge tray 12 is the same as the example shown in FIG. 1, and the description of these modes is omitted.

First, the face-up discharge mode for the paper discharge device 28 will be described. Lever 23 is the fixing device 9
The paper 13 that has passed through the feed direction 3
1, the sheet 13 that has passed through the fixing device 9 is carried into the conveyance path 34 as the first path of the conveyance direction reversing device 32 from the paper supply port 31, and
At 5, 43, the sheet is conveyed in the F direction. The paper 13 is directly carried out of the paper discharge port 40 of the transport direction reversing device 32 without reversing the transport direction by the transport direction reversing unit 41, and an image is formed on the fixed bin tray 26 or the movable bin tray 27 of the paper discharge device 28. The paper is ejected with the surface facing up, and the printing operation ends.

Next, in the face-down paper discharge mode to the paper discharge device 28, the lever 23 is set in a rotating posture for guiding the paper 13 passing through the fixing device 9 to the paper feed port 31 of the transport direction reversing device 32. As a result, the sheet 13 that has passed through the fixing device 9 is carried into the carrying path 34 of the carrying direction reversing device 32 from the paper supply port 31, carried in the direction of arrow F by the carrying rollers 35 and 43, and carried into the carrying direction reversing unit 41. Is done. When the trailing end of the sheet 13 loaded into the transport direction reversing unit 41 is detected by a sheet detection sensor (not shown) disposed near the entrance 42 of the transport direction reversing unit 41, the transport roller 43 separates from the sheet 13. Instead, the transport roller 48, which has been separated, sandwiches the sheet 13. The transport roller 48 rotates so as to transport the paper 13 of the transport direction reversing unit 41 in the B direction. At this time, the levers 44 and 45 are at the rotational positions for guiding the paper 13 unloaded from the transport direction reversing section 41 to the transport path 46 as the second path.
The paper 13 is transported along the transport path 46 by 8, 50 and 51. As a result, the paper 13 is discharged from the paper discharge port 40 of the transport direction reversing device 32 and discharged to the fixed bin tray 26 or the movable bin tray 27 of the paper discharge device 28 with the image formed on the lower side, and the printing operation is performed. Ends.

In the double-sided printing mode in the image forming apparatus 1,
The lever 23 is at a rotational position for guiding the paper 13 passing through the fixing device 9 to the paper feed port 31 of the transport direction reversing device 32,
The paper 13 that has passed through the fixing device 9 is carried into the transport path 34 of the transport direction reversing device 32 from the paper feed port 31 and is transported by the transport rollers 3.
At 5 and 43, the sheet is conveyed in the F direction, and is conveyed into the conveyance direction reversing section 41. When the trailing end of the sheet 13 carried into the carrying direction reversing section 41 is detected by the sheet detecting sensor near the carrying-in port 42, the carrying roller 43 separates from the sheet 13,
Instead, the transport roller 48, which was in a separated state, is
Hold 3 The transport roller 48 rotates so as to transport the paper 13 of the transport direction reversing unit 41 in the B direction. The operation up to this point is the same as the face-down sheet discharge mode for the sheet discharge device 28 described above. At this time, the levers 44 and 45 are at a rotational position where the sheet 13 carried out from the conveyance direction reversing unit 41 is guided to the conveyance path 49 as a third path, and the sheet 13 is conveyed by the conveyance rollers 48, 50 and 51. 49
Is transported. As a result, the paper 13 is carried out of the paper outlet 52 of the conveyance direction reversing device 32 and is again carried into the printing unit of the image forming apparatus 1.

FIG. 7 is an explanatory diagram showing an embodiment of the image forming apparatus system according to the seventh aspect of the present invention.

This embodiment is different from the image forming apparatus shown in FIG. 6 in that the mechanism for switching the front and back sides of the image forming surface of the sheet 13 is eliminated.
Other than the face-up paper discharge mode, the operation is the same as the example of FIG.

[0050]

According to the present invention, only one transport direction reversing means is provided for the entire image forming system.
To have a function of a mechanism for switching the front and back of the image forming surface of the print medium in the print medium discharge device, a mechanism for printing both sides of the print medium in the image forming apparatus, and a mechanism for switching the front and back of the image forming surface of the print medium in the image forming apparatus Can be. Accordingly, it is possible to eliminate a useless space below the double-sided printing device for avoiding interference between the respective installation spaces of the double-sided printing device and the sheet discharging device, thereby reducing the installation space. Further, by sharing the conveyance direction reversing mechanism required for the double-sided printing device and the sheet discharging device at one place, the product price of the entire image forming system can be reduced.

Further, since the image forming apparatus and the print medium discharging device are located on the intermediate conveyance path, the image forming device and the print medium discharging device can be used as a common optional mechanism for the image forming device and the print medium discharging device. Can be attached to any of the above.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an embodiment of an image forming apparatus system according to the invention of claim 3;

FIG. 2 is an explanatory diagram showing an embodiment of the image forming apparatus system according to the first aspect of the present invention;

FIG. 3 is an explanatory diagram showing an embodiment of an image forming apparatus system according to the invention described in claim 2;

FIG. 4 is an explanatory diagram showing an embodiment of the image forming apparatus system according to the invention of claim 4;

FIG. 5 is an explanatory diagram showing an embodiment of the image forming apparatus system according to the invention of claim 5;

FIG. 6 is an explanatory diagram showing an embodiment of the image forming apparatus system according to the invention of claim 6;

FIG. 7 is an explanatory diagram showing an embodiment of the image forming apparatus system according to the invention of claim 7;

FIG. 8 is an explanatory view showing the internal structure of a conventional color image forming apparatus and a duplex printing apparatus.

FIG. 9 is an explanatory diagram showing the internal structure of a conventional color image forming apparatus and a stacker.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 Image forming apparatus 2 Laser unit 3 Photoconductor drum 4 Developing device 5 Developing roller 6 Intermediate transfer belt 7 First transfer roller 8 Second transfer roller 9 Fixing device 10 Cassette 11 Pickup roller 12 Top surface discharge tray 13 Paper (recording) Medium) 14 Charger 15 Cleaning member 16 Registration roller 17 Lever 18 Transport roller 19 Toner 20, 21 Transport roller 22 Double-sided printing device 23, 24, 25 Lever 26 Fixed bin tray 27 Moving bin tray 28 Paper discharge device 29 Transport roller 30 Discharge port 31 paper feed port 32 transport direction reversing device 33,44,45 lever 34,37,38,46,49 transport path 53 lever 35,36,39,43,47,48,50,51 transport roller 40 paper discharge port 41 Transport direction reversing part 42 Carry entrance 52 Paper discharge port

Claims (8)

[Claims] 1. A conveyance direction reversing unit having a conveyance direction reversing means for a print medium, and a first path for conveying a print medium on which an image is formed and discharged by an image forming unit of the image forming apparatus to the conveyance direction reversing unit. A second path for transporting the print medium, on which an image has been formed by the transport direction reversing unit, to a print medium discharge device, and the printing medium, on which the image has been formed by the transport direction reversing unit, of the image forming apparatus. A third path for re-transporting to the image forming unit, a fourth path for directly transporting the print medium on which an image has been formed by the image forming unit of the image forming apparatus to the print medium discharge device, A first transport mode for transporting the print medium from the first route through the transport direction reversing unit to the second route, and the printing from the first route to the third route via the transport direction reversing unit; Transport media And a third transport mode for directly transporting the print medium, on which an image has been formed by the image forming unit of the image forming apparatus, to the print medium discharge device in a second transport mode and a fourth pathway. A transport direction reversing device, comprising: switching means; and transport means for transporting the print medium. 2. A conveyance direction reversing unit having a conveyance direction reversing means for a print medium, and a conveyance and a conveyance direction of the printing medium on which an image is formed and discharged by the image forming unit of the image forming apparatus. A first path used by the reversing unit to reversely transport the print medium to the print medium discharge unit of the image forming apparatus, and a print medium on which an image is formed by the transport direction reversing unit is transferred to the image forming apparatus. A third path for transporting the print medium again to the image forming unit, a second transport mode for transporting the print medium from the first path to the third path via the transport direction reversing unit, and the first path A path switching unit that can take a fourth transport mode for transporting the print medium to the first path again through the transport direction reversing unit; and a transport unit that transports the print medium. Carrying Direction reversing device. 3. A conveyance direction reversing section having a conveyance direction reversing means for a printing medium, and a conveyance and a conveyance direction of the printing medium on which an image is formed and discharged by the image forming section of the image forming apparatus to the conveyance direction reversing section. A first path for reusing the print medium from the reversing unit to the print medium discharge unit of the image forming apparatus, and a print medium on which an image is formed from the transfer direction reversing unit to a print medium discharge device A second path for conveying, a third path for re-conveying the print medium on which an image has been formed by the conveying direction reversing section to the image forming section of the image forming apparatus, and a third path for forming the image in the image forming apparatus. A fourth path for directly transporting the print medium on which an image is formed by the unit to the print medium discharge device, and transporting the print medium from the first path to the second path via the transport direction reversing unit Do A first transport mode, a second transport mode for transporting the print medium from the first path to the third path via the transport direction reversing unit, and a fourth path for the image formation of the image forming apparatus. A third transport mode for directly transporting the print medium on which an image has been formed by the unit to the print medium ejection device, and transferring the print medium from the first path to the first path again via the transport direction reversing unit. A transport direction reversing device, comprising: a path switching unit capable of taking a fourth transport mode for transporting; and a transport unit for transporting the print medium. 4. A transport direction reversing section having a transport direction reversing means for a print medium, and a first path for transporting the print medium on which an image has been formed and discharged by the image forming section of the image forming apparatus to the transport direction reversing section. A second path for transporting the print medium, on which an image has been formed by the transport direction reversing unit, to a print medium discharge device, and the printing medium, on which the image has been formed by the transport direction reversing unit, of the image forming apparatus. A third path for re-transporting to the image forming unit, a first transport mode for transporting the print medium from the first path to the second path via the transport direction reversing unit, and the first path A path switching unit capable of taking a second transport mode for transporting the print medium to the third path via the transport direction reversing unit;
A transport unit for transporting the print medium. 5. A transport direction reversing unit having a transport direction reversing unit for a print medium, and a transporting unit that transports the print medium on which an image is formed and discharged by the image forming unit of the image forming apparatus to the transport direction reversing unit and the transport direction. A first path for reusing the print medium from the reversing unit to the print medium discharge unit of the image forming apparatus, and a print medium on which an image is formed from the transfer direction reversing unit to a print medium discharge device A second path for transporting the print medium, a third path for transporting the print medium on which the image has been formed from the transport direction reversing section to the image forming section of the image forming apparatus, and a transport from the first path. A first transport mode for transporting the print medium to the second path via a direction reversing unit, and a second transport mode for transporting the print medium from the first path to the third path via the transport direction reversal unit. Transport mode A path switching means from fine the first path may take a fourth conveyance mode of conveying the printing medium back to the first path via the transport direction reversing unit,
A transport unit for transporting the print medium. 6. A transport direction reversing section having a transport direction reversing means for a print medium, and transporting the print medium on which an image is formed and discharged by the image forming section of the image forming apparatus to the transport direction reversing section and the transport direction. A first path that is used by the reversing unit to reversely convey the print medium to the print medium discharge unit of the image forming apparatus; and a print medium discharge unit that conveys the print medium whose conveyance direction is reversed by the conveyance direction reversal unit The second to transport
A third path for re-transporting the print medium, the transport direction of which has been reversed by the transport direction reversing unit, to the image forming unit of the image forming apparatus, and a transport direction reversing unit from the first path. A first transport mode for transporting the print medium to the second path via the second path, and a second transport mode for transporting the print medium from the first path to the third path via the transport direction reversing unit. And a fourth transport mode for transporting the print medium from the first path to the first path again via the transport direction reversing section, and the transport direction reversal without reversing the transport direction from the first path. A conveyance direction reversing device, comprising: a path switching unit capable of taking a fifth conveyance mode for directly conveying the print medium to the print medium discharge device via a unit; and a conveyance unit for conveying the print medium. 7. A transport direction reversing section having a transport direction reversing means for a print medium, and a first path for transporting the print medium on which an image is formed and discharged by the image forming section of the image forming apparatus to the transport direction reversing section. A second path for transporting the print medium, on which an image has been formed by the transport direction reversing unit, to a print medium discharge device, and the printing medium, on which the image has been formed by the transport direction reversing unit, of the image forming apparatus. A third path for re-transporting to the image forming unit, a first transport mode for transporting the print medium from the first path to the second path via the transport direction reversing unit, and the first path A second transport mode for transporting the print medium to the third path via the transport direction reversing section and the print medium discharge via the transport direction reversing section without reversing the transport direction from the first path. Before the device A path switching means capable of forming a fifth transport mode for conveying a printing medium directly, the transport direction reversing device, characterized in that it comprises a conveying means for conveying the printing medium. 8. An image forming apparatus which is disposed on a conveyance path intermediate between the image forming apparatus and the print medium discharging apparatus, and which is a common optional mechanism between the image forming apparatus and the print medium discharging apparatus. 2. The printing apparatus according to claim 1, wherein the printing apparatus can be attached to any one of a printing medium discharging apparatus.
8. The transport direction reversing device according to any one of 3, 4, 5, 6 and 7.