JP2807317B2 - Paper transport mechanism of image forming apparatus - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus in which a finisher for post-processing of recording paper such as a sorter is attached to an image forming main body. The present invention relates to a mechanism for conveying recording paper supplied to the apparatus.

2. Description of the Related Art As is well known, in various image forming apparatuses such as a copying machine, a printer, and a facsimile, a finisher including a sorter for recording paper sorting or the like is sometimes attached to an image forming main body.

A general image forming main unit is often of a side operation type that performs operations such as discharging and sorting of recording paper in a side region of the main unit.

For this reason, the image forming main body is provided with a conveying path for image forming for conveying the recording paper from one side to the other side, and the finisher is configured to move the image on the image forming main body. They are connected side by side at the outlet of the forming conveyance path, that is, at the side of the image forming main body.

[Problems to be Solved by the Invention] However, in such an image forming apparatus, as described above, since the image forming main body is configured as a side operation type, the entire apparatus becomes long in the left-right direction. In addition, the image forming apparatus performs various operations such as taking out the recorded recording paper on which the image has been formed from the tray, or mounting a paper feed cassette storing the unrecorded paper in the image forming main body. On both sides. Therefore, spaces for the above-described operations are required on both sides of the image forming apparatus.

Moreover, in this space, it is necessary to provide a margin for preventing a pedestrian from colliding with a tray or the like. Therefore, when installing an image forming apparatus, in consideration of such circumstances, actual operation is performed. Therefore, a space having a size larger than that required for the space is required. Therefore, when such an image forming apparatus is installed in a relatively narrow space, the above-described various operations may be hindered.

Therefore, in order to solve such a problem, the recording paper transport path described above is converted from the inside of the image forming main body to a right angle direction and set toward the near side and the far side with respect to the image forming main body. (For example, Japanese Patent Application No. 1-150842 filed by the present applicant).

However, in the image forming apparatus in which the above-described conveyance path is set, for example, in a case where continuous paper feeding is performed, it is necessary to prevent a succeeding recording sheet from interfering with a preceding recording sheet when the conveyance direction is switched. is required. For this reason, the recording paper conveyance interval is increased, or
By increasing the speed at the time of right angle conveyance, a device for suppressing a decrease in the speed at the time of continuous paper feeding has been devised. However, in such a method, since the conveyance interval is not constant depending on the type of recording paper being conveyed, it is quite troublesome to control the conveyance speed in accordance with the type of recording paper being conveyed. It becomes something.

Further, the conventional image forming apparatus has the following problem because the length of the recording paper to be conveyed is set such that the maximum length can be conveyed.

That is, the copying modes in the above-described image forming apparatus include one-sided copying, two-sided copying, and one-sided combined copying, and a length sufficient to convey a recording sheet corresponding to each mode is set in the image forming apparatus. The paper sizes that are commonly used are B4, A4, and B5, and the paper size that is often used for duplex copying is
A4 and B5.

Therefore, when conveying the recording paper of the size of the high copy frequency described above, if a conveyance path set for conveying the recording paper of a size equal to or more than these sizes is used for conveying each of the recording papers, In the case of double-sided copying, the time required to shift to the next image formation becomes longer, and the copying operation becomes longer due to the longer copying time.

In addition, if the recording paper is ejected to the upper surface of the image forming apparatus, there is a possibility that the original placing table may be overlapped with the original setting position because the original placing table is located on the upper surface. There is no way to do it.

In addition, it is difficult in terms of position to connect a recording paper sorting sorter, stapler, or other peripheral device used for processing the discharged recording paper to the above-described recording paper discharge unit.

Furthermore, the above-described recording paper is often ejected with the image side facing up, and the ejected recording paper is placed in the reverse order of the page order on the document side. Will be placed. Therefore, in order to improve the integrity of the recording sheets after copying, there is the inconvenience that copying must be performed from the rear side in the page order of the document. However, when performing copying in such a procedure, if an odd-numbered single-sided original is to be double-sided, the completed copy will be blank instead of the first page, and the original will be blank after the second page. The non-page order processing in which the image from the first page is copied will occur.

Therefore, the present invention can reduce the size of the apparatus itself, does not need to provide a large operation space around the apparatus, can be installed in a small space, and can perform high-speed and efficient paper conveyance. It is still another object of the present invention to provide an image forming apparatus capable of discharging recording paper in the order of pages of a document.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a forward transport path for transporting a recording sheet on which an image is formed and discharged toward a near side and a far side. A front-operation-type image forming main body, a finisher for post-processing of recording paper arranged side by side on the side of the image forming main body, and a substantially right-angle direction for receiving the recording paper discharged from the forward conveyance path. And a right-angle transport path connected to the forward transport path so as to feed the recording paper to the finisher. The paper feeding means in the right-angled conveying path is provided with a common switching mechanism for selectively switching between operation and stop of the conveying operation.

Further, the present invention includes a forward transport path for transporting a recording sheet on which an image is formed and discharged at a predetermined image forming process speed toward a front side and a rear side at a predetermined paper feed speed. A front-operation-type image forming main body, a finisher for post-processing of recording paper arranged side by side on the side of the image forming main body, and a substantially right-angle direction for receiving the recording paper discharged from the forward conveyance path. And a right-angle transport path connected to the forward transport path so as to feed the recording paper to the finisher.In the paper transport mechanism of the image forming apparatus, the paper transport means in the forward transport path is , together and is configured to allow selecting one of the image forming process speed and the same paper conveyance speed V ₁ and the paper was increased at a constant relationship to the image forming process speed conveying speed V ₂ , The paper feeding means in the forward direction transport path is configured such that the paper transport speed is determined based on the recording paper having the largest difference (hi) between the paper width dimension h and the interval dimension i between the recording papers in the transport direction of the recording paper. It is configured to be set.

Further, in the present invention, the paper feeding means in the forward transport path in the forward transport path is configured such that the paper transport speed is set by a signal for detecting the rear end of the recording paper immediately after leaving the fixing device. It is characterized by having.

And also, the present invention is a paper feeding means in the forward conveying path, along with and is configured to include the imaging process speed and the same paper conveyance speed V _1, the paper feeding means in a direction perpendicular the conveying path, create It is characterized in that it is configured with the sheet conveying speed V ₂ at elevated fixed relationship with respect to the image processing speed.

Further, according to the present invention, the paper feeding means in the forward transport path sets the paper transport speed for each size of the recording paper based on the paper width dimension h of the recording paper and the interval dimension i between the recording papers. It is characterized by having such a configuration.

Still further, the present invention is provided with a conveyance path in which the conveyance direction of the recording paper is set from the near side to the back side with respect to the operation surface of the copying machine, and the conveyance and circulation are performed in this conveyance direction.
An image forming apparatus provided with a discharge port for the recording sheet on one of a top surface of the copying machine and a side portion of the copying machine corresponding to a direction perpendicular to the carrying direction in the carrying path, wherein A small-size switchback conveyance path, which is provided immediately downstream of the fixing device in the conveyance direction and is provided separately from the discharge port on the upper surface side and sets a conveyance path to a double-sided copy refeeding apparatus; A large-size switch that is located downstream of the small-size switchback transport path in the transport path, branches from the discharge path toward the discharge port on the top of the copying machine, and sets a transport path toward the double-sided copy refeeding device. A back transport path, a composite copy transport path for setting a transport path branching from a discharge path toward the discharge port on the top surface of the copying machine and heading to the double-sided copy refeeding device, A right-angle transport path that branches from a transport path set for double-sided copying and composite copying for recording paper and changes the transport direction of the recording paper to a right-angle direction at a position different from the refeeding device for double-sided copying. It is characterized by having.

The present invention relates to a method for conveying a recording sheet when the recording sheet is performing an image transfer process with a photosensitive member for image formation in a conveying path from a front side to a back side with respect to an operation surface. When the speed is V1 and the transport speed of the recording paper during execution of the other copy processes is V2, the relationship of V1 <V2 is set.

Further, the present invention is also directed to a recording medium which is branched from a conveyance path set for double-sided copying and composite copying of large-size recording paper, and the conveyance direction of the recording paper is set to a right angle in a position different from the double-sided copying refeeding device. A sheet reversing storage unit that is located on an extension of the right-angled conveyance path and that stores the conveyance direction of the recording paper conveyed from the right-angled conveyance path while accommodating the direction of the image surface of the recording paper. It is characterized by having.

[Operation] In the means according to the present invention, first, since the image forming main body is configured to be a front operation type, the recorded paper on which the image has been formed is taken out from the tray or the unrecorded paper is stored. All operations such as attaching the paper cassette to the image forming main unit are performed from the front of the image forming apparatus, so there is no need for operation space or extra space on both sides of the apparatus. Thus, three sides except the near side of the apparatus can be brought close to the wall surface.

Further, with respect to the finisher arranged side by side of the image forming main body, the paper recorded in the direction substantially perpendicular to the feeding direction of the forward conveying path from the perpendicular conveying path of the image forming main body is turned. The post-processing operation such as the recording paper sorting operation is performed. Then, the recording paper after the post-processing is also taken out from the near side. For this reason, even in the finisher, an operation space and a space for extra space are not required on both sides of the apparatus, and three sides except the front side of the apparatus can be brought close to the wall surface.

In such a right-angle discharge operation for the finisher, the operation of switching the recording sheet conveyance direction when moving from the forward conveyance path to the right-angle conveyance path is performed by a single switching mechanism having a simple configuration. The certainty and high speed of the operation for switching the sheet conveyance direction are improved.

Also, in the above-described right-angle discharge operation for the finisher, the paper feed speed in the forward conveyance path is determined so that the interval between the preceding recording sheet and the succeeding recording sheet in the forward conveyance path is equal to or greater than a certain value. As a result, the preceding transfer paper is received at the entrance of the right-angled conveyance path, and after being sent out therefrom, the subsequent transfer paper enters the entrance of the right-angled conveyance path, and the An interference state due to overlap between a preceding recording sheet and a succeeding recording sheet at the entrance is reliably prevented, and a favorable discharging operation is performed.

Further, according to the present invention, when a small-sized recording sheet is duplex-copied, the recording sheet is immediately introduced into the small-size switchback transport path in the transport path after the image is fixed, and re-feeded for duplex copying. Brought to the device.

Further, according to the present invention, the transport time of the recording paper other than at the time of transfer is reduced.

Further, according to the present invention, it is possible to switch the image side of the discharged recording paper to either the front side or the rear side and discharge the recording sheet, and it is possible to set the page order to a desired order.

[Example] Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

First, the structure of the image forming main unit in the image forming apparatus according to the embodiment of the present invention will be described together with its function in the copying machine shown in FIG.

That is, the image forming main body section includes a copier main body C and a multi-stage paper feeder (P
B) 400, and an automatic reversing original device (ARDF) 100 installed on the upper part of the copying machine main body C.

In the copying machine main body C, the document to be copied is inserted from the position shown by the arrow A, and is stopped at a predetermined position on the contact glass 203. The operation of the original set will be described in detail in the section of the automatic reversing original feeder (ARDF) described later.

Next, an exposure step is performed by the optical system 200. The optical system 200 is arranged so that the original image can be scanned below the contact glass 203. The original illumination light source 201, the movable mirrors 204, 205, and 206, the zoom lens 207, and the fixed mirror 20 are provided.
8,209,210. The document illumination light source 2
01, the reflector 202, and the movable mirror 204 constitute a first scanner 220. The first scanner 220 has a relative velocity (V) of the photosensitive drum 601 (V / m; m is a copy magnification). Is moved rightward at the speed of at the same time, and at the same time, the second scanner 230 composed of the movable mirrors 205 and 206 is (V / 2m)
The motor is rotationally driven by a drive motor (not shown) so as to be moved rightward in the drawing at the speed shown in FIG. The peripheral speed of the photosensitive drum 601 is constant irrespective of the same magnification or variable magnification.

The copy magnification is changed by driving the lens drive motor (not shown) to change the position of the zoom lens 207 on the optical path. In the figure, when the position of the zoom lens 207 is I, m = 0.5 (50% reduction), when it is H, m = 1.0 (actual magnification), and when G, m = 2.0 (20%).
0% magnification).

The photosensitive drum 60 is located on the slightly right side of the center of the copying machine main body C.
An image forming system 600 is provided around 1. That is, a charging charger 602 for uniformly charging the photosensitive drum 601 around the photosensitive drum 601, an eraser 603 for erasing unnecessary charges, and a first development for visualizing the toner powder on the electrostatic latent image by a magnetic brush. Device 502 and second developing device 501,
A belt transfer device 603 for transferring the toner image on the photosensitive drum 601 to the recording paper, a cleaning device 608 for cleaning the toner image remaining on the photosensitive drum 601 without being transferred to the recording paper, and the like are provided. I have.

In the belt transfer device 630, an endless belt 613 stretched by a plurality of rollers 614 and the like is lightly pressed against the photosensitive drum 601, and a corona discharge for transfer is performed by a charger 609 from the back. Charger 612
Is for charging the endless belt 613 and electrostatically attracting the recording paper. The charger 610 is a charger for removing static electricity from the endless belt 613. The rubber blade 615 is for cleaning the residue of the endless belt 613 after the paper is conveyed.

On the other hand, there are roughly two recording paper feeding units, one is a multi-manual paper feeding device 300 attached to the main body side, and the other is disposed below the copying machine bottom. A multi-stage paper feeder (PB) 400 including a plurality of paper feed trays. The paper guide 301 of the multi-manual feeder 300 is normally closed, and is opened as shown in the figure when used, whereby the recording paper is set.

Also, the loaded recording paper is
2, and only one sheet is fed by the sheet feeding roller 303 and the separation roller 304. Registration roller pair 305
After being temporarily stopped in, while being synchronized with the leading end of the image on the photosensitive drum 601, the setting is made from the front side of the operation unit corresponding to the right side in the figure to the back side of the operation unit corresponding to the left side in the figure The paper is fed along the transport direction. As the transport speed in this case, when the speed at the time of executing the transfer process is V1 and the speed at the time of performing the process other than this process is V2, the relationship of V1 <V2 is established, and the transport time is reduced. .

On the other hand, the sheet feeding operation by the multi-stage sheet feeding device 400 is performed by first feeding the sheet feeding device 410 toward the sheet tray of the selected sheet feeding stage.
Is raised and lowered. When the selected sheet reaches the tray, a signal from a sensor (not shown) is received and a sheet feeding device 41 is received.
The lifting drive of 0 is stopped, and then the paper tray is moved to the paper feeding device side. The paper feeding method is basically the same as that of the multi-manual paper feeding device.

That is, the paper is sent to the paper feed roller 412 by the calling roller 411, then separated and fed out by the paper feed roller 412 and the separation roller 413,
From the feeding position, for example, the sheet is fed toward the conveying roller 306 by a conveying belt 419 provided with a suction mechanism.

Then, the fed paper reaches the registration roller pair 305 via the transport roller 306 and is stopped. The sheet on which the toner image has been transferred while being held by the endless belt 613 after passing through the registration roller pair 305 is fused with the toner image by the heat roller pair (the fixing roller 701 and the pressure roller 702).
The recorded paper after fixing, that is, so-called recording paper (hereinafter referred to as transfer paper) passes through the pair of fixing discharge rollers 701 and 702 in the transport path along the transport direction described above, and is discharged on the upper surface of the copying machine main body. The paper feeds to the main body discharge tray 809, the re-feeding device 900, and the sorter transport unit 950 via the transport path 822 set to face the paper tray 809.

Immediately after passing through the above-mentioned fixing paper discharge roller pair, a sensor 801 for detecting the rear end of the transfer paper is arranged. On the downstream side of this sensor 801, a roller pair 802, 804 is provided by a guide gate 803. A transport path that constitutes a small-size switchback transport path that transports the transfer paper to the re-feeding apparatus 900 for duplex copying, which branches off from the transport path formed by
821 is provided. The small-size switchback transport path 821 is a transport path used when performing double-sided copying of transfer paper of A4 size or smaller, as described later.

In addition, the small size switchback conveyance path 821 described above is used.
Downstream of the switchback transport path 821 in the so-called recording paper transport direction, in order to detect the rear end of the transfer paper in the middle of the transport path toward the paper output tray 809 located on the top of the copying machine. The sensor 810 is disposed, and a roller pair 8 that can be rotated forward and backward is provided downstream of the sensor 810.
The roller pair 806 and the guide gate 811 diverge from the transport path formed by the roller pairs 802 and 804, and transport the transfer paper toward a double-sided copy refeeding device 900 described later. There is provided a transport path 824 which constitutes a switchback transport path.

That is, when performing double-sided copying, two different transport paths are used, roughly classified into A4 (or LT) size or smaller and other sizes.

First, if the size is smaller than A4 (or LT),
When the trailing edge of the transfer paper passes through 700, a signal from the signal of the sensor 801 is received and immediately after passing through the gate 803, the roller pair 8
02 is reversed, and the transfer paper goes to the conveyance path 821. After passing through the roller pair 901, the call roller 908 is lowered and rotated, and the transfer paper is conveyed immediately below the paper feed roller 909. Except during paper feeding, the pressure plate 911 is below, and is raised during paper feeding to apply paper feeding pressure to the paper feeding roller 909. The separation roller 910 is given a counterclockwise rotation at a certain torque or less, but is rotated with the paper feed roller 909 when a larger torque is applied. Are supplied one by one. The re-fed transfer paper is conveyed until a predetermined slack is given by the pair of registration rollers 305, then stopped, and restarted in synchronization with the leading edge of the image on the photoconductor. Subsequent operations are the same as those for one-sided copying.

Therefore, the small-sized recording paper of A size or less is introduced into the small-sized switchback conveyance path 821,
Since the recording paper larger than this size is fed to the double-sided copying refeeding device 900 without passing through the conveyance path, the feeding speed during the double-sided copying is also increased due to the high conveyance speed other than the transfer process. The time until the paper disclosure time is reduced.

On the other hand, in the case of paper having a size larger than A4 (or LT), the transfer paper passes through the fixing device and the guide gate 803 for introduction into the small-size switchback conveyance path,
When the trailing end is detected by the sensor 810 after passing through the pair of rollers 802 and 804 and passing through the gate 811, the pair of rollers 806 is reversed, and the transfer paper is directed to the above-described double-sided copy refeeding device 900 and described later. A transport path that constitutes a large-size switchback transport path for transporting transfer paper toward a right-angle transport path
Sent to 824. At this time, the gate 814 has been displaced to the position indicated by the broken line, and the transfer paper is sent to the roller pair 902.
When the transfer paper size is A3 (or 17 "), the gate 905
Takes the position indicated by the broken line and is discharged onto the refeeding device immediately after passing through the roller pair 902. Transfer paper size is B4 (or 1
In the case of 4 ″), the gate 905 assumes the position indicated by the solid line and the gate 906 assumes the position indicated by the broken line, so that the transfer sheet passing through the roller pair 903 is discharged onto the re-feeding device.
When the transfer paper size is A4 portrait or B5 portrait (or 11 ″), the gates 905 and 906 take the position of the solid line, the gate 907 takes the position of the broken line, and the transfer paper passing through the roller pair 904 is placed on the re-feeding device. The subsequent operations are the same as those described above for A4 and below.

On the other hand, in the copying machine main body C, in addition to the transport path set for the above-described double-sided copying, a transport path for combining (multiplexing) an image on one side of a transfer sheet is provided.

In other words, the above-described conveying path for the synthesis
4 is set from the gate 805 located on the downstream side to the double-sided copy refeeding device 900.

Then, when performing composite copying on this transport path, regardless of the size, the gate 805 is first displaced to the position indicated by the broken line, and the transfer paper after fixing is sent to the transport path 823. Next, the gate 814 is displaced to the position indicated by the broken line, and the transfer paper is sent to the roller pair 902. When the transfer paper size is A3 (or 17 ″), the gate 905 takes the position indicated by the broken line and is discharged onto the re-feeding device immediately after passing through the roller pair 902.
When the transfer paper size is B4 (or 14 ″), the gate 905 takes the position of the solid line and the gate 906 takes the position of the broken line, and is discharged onto the re-feeding device after passing through the roller pair 903. When the size is A4 portrait or B5 portrait (or 11 ″), the gates 905 and 906 take the position of the solid line and the gate 907 takes the position of the broken line, and the transfer paper passing through the roller pair 904 is discharged onto the re-feeding device. You.

The operation up to this point is the same as the above-described operation on both sides of paper having a size larger than A4 (or LT). Transfer paper size
The gates 905, 906, and 907 assume the positions indicated by the solid lines when the document is A4 horizontal (or LT or less), and are discharged onto the sheet re-feeding device after passing above the gate 907. In order to align the discharged transfer paper, a pair of call rollers 908 is operated. Subsequent operations are the same as in the above-described duplex copying.

The configuration and operation of the automatic reversing original document apparatus (ARDF) 100 will be described with reference to FIGS.

First, in the case of a single-sided original, the original to be copied is set on the tray 101 in the direction of arrow A with the image side up. The set document is fed by a feeding mechanism similar to that of the multi-manual feeding device.

That is, the document is pulled in the left direction by the calling roller 102, and then the paper feeding roller 10 is rotated clockwise.
Only the uppermost original is fed toward the roller pair 106 by 3 and the separation roller 104 also rotated clockwise.

In this automatic document feeder, a document is fed in page order. The roller pair 106 is stopped until the document is sent, and starts rotating a little after the leading end of the document is reached. Thus, the skew (skew) of the document is corrected.

Then, after passing through the roller pair 107, it is guided by the guide plate 123 and is sent between the contact glass 203 and the transport belt 118. The transport belt 118 includes the drive roller 115 and the roller 11
It is stretched by 6 and a tension roller 117.
The stop position of the document on the contact glass 203 is determined by the number of pulses starting from when the rear end of the document passes the sensor 127.

When scanning of the document is completed, the transport belt drive roller
Reference numeral 115 denotes a document which is rotated clockwise and fed back to the left in the form of switchback. The first gate 111, which was initially at the position shown by the solid line, is displaced to the position shown by the broken line in FIG. That is, the state shown by the solid line in FIG. Roller 11 at the top of the manuscript
The paper passes between the roller 2 and the roller 113 and is discharged onto the tray 119.

In this state, the image cotton of the original is on the top side,
If the paper is continuously discharged as it is, the page order is reversed. In order to avoid this, the device is again inverted. That is, at the same time when the rear end of the document is detected by the sensor 128, the rollers 108 and 113 are rotated counterclockwise. At the same time, the second gate 110 is switched to the solid line position shown in FIG. 3B based on the inverted signal, and the first gate 111 is also changed to the lower solid line position. Thus, as shown in FIG. 3 (c), the originals are stacked on the tray 119 with the image side down, passing between the rollers 113 and 114. The same operation is repeated sequentially, and the originals are stacked in the same page order as when they were first set.

For double-sided documents, the first side should be
The operation is the same as in the single-sided mode up to the stop on the upper side. When scanning of the document is completed, the transport belt driving roller 115
Is rotated clockwise and the document is sent out to the left in the form of being switched back. At this time, the first gate 111 is displaced upward as in the case of a one-sided original, and
The position of the gate 109 is also changed upward. That is the third
This is shown in FIG.

In FIG. 3D, the leading end of the original to be inverted is guided by guides 121 and 122 and is sent back onto the contact glass 203 again. The stop position of the document on the contact glass 203 is determined by the number of pulses from the time when the rear end of the document has passed the sensor 38.

When the scanning of the document on the second side is completed, the transport belt driving roller 115 is rotated clockwise to switch back, and the document is fed leftward. At this time, the third gate 109 is displaced downward, and the original is moved to the rollers 12 and 113 in a state as shown in FIG.
Are stacked on the tray 119, and the operation of feeding and discharging the double-sided document is completed. Thereafter, the same operation is sequentially repeated, and the originals are stacked in the same page order as when they were first set.

On the other hand, a sorter 1000 as shown in FIG. 4 is arranged side by side on the image forming main body.

To this sorter 1000, the recording paper is sent in such a manner that the direction of the recording paper is changed in a substantially right angle direction from the double-sided copying refeeding device constituting the image forming conveyance path in the image forming main body. . That is, in the re-feeding device 900 of the image forming apparatus main body shown in FIG. 1, the transfer direction of the transfer sheet brought to the near side (the right side in the figure) with respect to the operation unit in FIG. A sorting discharge conveyance path to be conveyed is provided as described later, and A3 and
Since the paper sent in the length of B4 is sent short, it has excellent transport efficiency.

The sorter 1000 can switch the front and back sides of the transfer paper to be discharged, that is, the direction of the image surface immediately after the end of the image formation. First, the case where the sorter does not switch will be described.

That is, when copying in page order, the copied paper is stacked with the image side down, or if the image side is up, it is inserted under the previous transfer paper and remains in the same state as the original. However, the latter method is not so common in terms of simplicity, and the former method is more general.

The above-described operation of turning the upper surface of the transfer sheet to the back side for discharging the back surface is performed on the image forming main body side shown in FIG. In other words, gate 80
By switching to the position indicated by the broken line 5 in FIG.
The sheet is sent to the roller pair 922 through 3,826, and as shown in FIG. 1, is sent by the vertical conveying rollers 923, 924, 925 as forward conveying rollers with the sorter conveying path 921 image side down. At this time, the right angle transport roller 92
Pinch roller 926a as a pressure roller constituting 6
Are retracted so as to be separated upward.

The leading edge of the transfer paper that has exited the roller 925 is detected by the photo sensor 927, and is stopped after being fed for a predetermined time.
Subsequently, the pinch rollers 923a, 924a, and 925a as the pressure rollers constituting the vertical conveyance rollers 923, 924, and 925 are retracted so as to be respectively separated upward, and the pinch roller 926a of the right-angle conveyance roller 926 is lowered to hold the transfer paper. And is conveyed to the near side with respect to the paper surface shown in FIG.

As shown in FIG. 4, the transfer paper sent from the image forming main body passes through a guide plate 1301, and is guided upward by a gate 1302. Further, as shown in FIG. 5, after the gate 1104a is rotated counterclockwise and the first transfer paper passes through the pair of rollers 1102a and 1103a, the bin tray 1101a
Is sent to Gate 1104b for second transfer paper
Are opened, and the gate is sequentially opened such that the gate 1104c is opened for the third transfer sheet.
Stacked into 1101c bin tray. The gate 1105 for the tenth bin 1101j is fixed at the always open position.

On the other hand, in the front-side discharge with the image side up, first, the transfer sheet is switched back in the image forming main body in the same manner as in double-sided copying, and is sent to the sorter conveyance path. The transfer operation of the transfer paper from the sorter conveyance path to the sorter is the same as that of the backside discharge.

The operation of switching between front-side discharge and back-side discharge on the sorter 1000 side will be described by using a method in which sheet processing on the image forming main body side is stacked on a re-feeding device without switchback as in the case of composite copying. Since the image is conveyed to the guide plate 1301 with the image side down, the above-described operation is performed when the back side is discharged.

That is, the gate 1302 is positioned below, and the transfer paper is directly guided to the upper ten bin sorters. The front side discharge is
The gate 1302 is positioned above, and the transfer paper is first guided to the lower ten bin sorters. The right side of the transfer paper at this time is the image surface. When the sensor 1210 detects the trailing end of the transfer paper, the rollers 1307, 1205, 1206, and 1207 are inverted, and the transfer paper switches back to the upper ten bin sorters. The stacking in each bin is the same as that for the back side discharge, but the image side is on the tray.

Also, as shown in FIG. 6, in the lower 10 bin sorters, the gate 1302 is displaced upward, and the transfer paper passes through the roller pair 1307 by being guided downward by the guide plate 1301. When the first sheet (the 11th sheet is correct since it is the operation after the 11th bin), the gate 1204a is opened and passes through the rollers 1202a and 1203a, and the bin tray 1
Stacked on 201a. Subsequent gates 1204b, 1204c
Is opened and stacked on the trays 1201b and 1201c.

Next, switching between front-side discharge and back-side discharge is performed by a sorter.
The operation performed on the 1000 side will be described.

In the case of back side discharge, the gate located directly above
1302 heads directly down to the 10 bottle sorters. In the case of front side discharge, as shown in FIG.
Is located below and after passing through the guide plate 1301, is first sent upward. At this time, the image surface is on the left side of the transfer paper in the figure. When the trailing end of the transfer paper is detected by the sensor 1110, the rollers 1102 and 1103 are inverted, whereby the transfer paper is switched back. The subsequent operation is the same as the other stacking operation, in which the gate 1204 is opened, passes through the pair of rollers 1202, 1203, and is stacked on the tray 1201.

FIG. 7 shows a state in which a further 20 bottle sorters are provided in addition to the 20 bottle sorters. The additional 20 bottle sorters have a similar internal configuration. The transfer of the transfer paper to the additional 20-bin sorter is performed by sewing between the 10 bin sorters. At this time, the gate 1302 is set at an intermediate position as shown in FIG. 8 (b).
The transfer paper that has passed through the guide plate 1301 is moved horizontally as it is and passes through the rollers 1304, 1035, and 1306. The operation after passing through the guide plate 1303 is the same as the operation of the 20 bottle sorters after the guide plate 1301.

On the other hand, the operation / stop of the transport operation in the forward transport rollers 923, 924, 925 and the right-angle transport roller 926 is selectively switched by a common switching mechanism as described later with reference to FIG. It has become.

That is, in this embodiment, A4 size paper is 40 cpm (copy p
er minute, 40 copies per minute), 27 cp with B4 longitudinal feed
m, is configured as a machine of 23cpm with A3 longitudinal feed, after the rear end of the maximum size paper passes through the fixing roller 701,
The leading end of the paper is held by the forward transport roller 923.

As described above, in the forward transport rollers provided in the forward transport path and the right-angle transport path, the pinch rollers 923a, 924a, and 925a are fixed to the drive rollers 923, 924, and 925 that are constantly rotated. A right-angle discharge operation with respect to the sorter is performed by performing the pressing or separating operation at the timing.

That is, the pinch rollers 923a, 924a, 925a serving as pressure contact rollers are pressed against the drive rollers 923, 924, 925 constituting the forward transfer rollers of the forward transfer path, so that the right-angle transfer is performed from the forward transfer path. While the recording paper is transported to the path, when the recording paper comes to a predetermined position, the drive rollers 923, 924, 925 described above,
When the above-described pinch rollers 923a, 924a, and 925a are detached, application of the forward conveyance force to the recording paper is stopped.

At the same time, a pinch roller 926a constituting a pressure roller is pressed against the above-mentioned drive roller 926 constituting a right-angle conveyance roller, whereby a conveyance force in a right angle direction is applied to the recording paper, and Thus, the recording sheet is always changed at a fixed position and quickly changed direction and sent to the sorter.

A configuration for performing the above-described operation is shown in FIG.

That is, in FIG. 9, the forward conveying roller
Pinch rollers 923a, 924a, 925a against 923,924,925
Are urged in the pressing direction via the support shafts 951, 952, 953 by elastic members 941, 942, 943 such as springs, and the pinch roller 926a with respect to the right-angle transport roller 926 is supported by the elastic member 944 such as a spring. It is urged in the pressing direction via 954.

The support shaft 953 of the pinch roller 925a and the pinch roller 9
The support shaft 954 of the pinch roller 926a extends in a direction perpendicular to the support shaft 954, and is fixed to the tip of the support shaft 953 of the pinch roller 925a. Meshed with a bevel gear 954a that is fixed to the gear. As a result, the rotation operation of the support shaft 953 is
The rotation is transmitted to the 54 side, so that both support shafts simultaneously perform a rotational movement.

The forward transport rollers 923, 924, and 925 obtain rotational driving forces from input pulleys 931, 932, and 933, respectively, and the right-angle transport rollers 926 obtain rotational driving forces from input pulleys 934.

The transfer paper is transported at a predetermined speed by the transport action of the forward transport rollers 923, 924, 925. After passing through the forward transport roller 925 at the most downstream, the leading edge is detected by the paper detection sensor 927, and the stop position is determined by the signal. Stop with the tip aligned with 928. At the same time, the transport direction is switched 90 degrees as follows.

The switching operation of the transport direction is performed by the pinch roller.
It is performed by the suction operation of each plunger solenoid 961, 962, 963 connected to the support shafts 951, 952, 953 of 923a, 924a, 925a. That is, each plunger solenoid
By the suction operation of 961, 962, 963, each support shaft 951, 952, 953 is rotated over a certain angle, whereby the pinch rollers 923a, 924a, 925a of the forward transport rollers 923, 924, 925 are retracted to the open position and the transfer paper is stopped, 95
Rotational motion of No. 3 is transmitted to the support shaft 954 side, whereby the pinch roller 926a of the right-angle direction conveyance roller 926 is urged to apply a right-angle conveyance force to the transfer paper.

Other means such as a cam can be adopted as such a transport direction switching mechanism. In this way, the transfer paper is transported by changing the direction by 90 degrees, so that the recording paper is always changed at a fixed position and quickly changed and transported in the right angle direction, and is sent out to the sorter. It will be.

As soon as the preceding transfer paper P1 is retracted, the suction operation of the plunger solenoids 961, 962, 963 is released, and the pinch rollers 923a, 924a, 925a are urged under the tension of the elastic members 941, 942, 943. As a result, the transport force is again applied to the forward transport rollers 923, 924, and 925, so that the forward transport rollers 923, 924, and 925 are prepared for the subsequent transport of the transfer paper P2.

In the present embodiment, each conveying roller in the forward transport path, identical to the paper conveyance speed V ₁ and operation process speed,
It is configured to be able to select either the paper transport speed V ₂ increased in a fixed relationship to the operation process speed, and the transport speed of the forward transport rollers in these forward transport paths is The setting is made based on the paper width dimension h in the transfer paper transport direction and the interval dimension i between the respective transfer papers. More specifically, as will be described later, the transfer paper having the largest difference m (m = hi) between the paper width dimension h in the transport direction of the transfer paper and the interval dimension i between the respective transfer papers is sequentially referred to as a reference. The paper transport speed in the direction is set. In addition, the switching operation of the paper conveyance speed at this time is performed based on the trailing edge detection signal of the transfer paper immediately after leaving the fixing device 700.

Hereinafter, this will be specifically described for the case of A4 horizontal feed (short feed), the case of B4 vertical feed (long feed), and the case of A3 vertical feed (long feed). Note each conveying roller in the direction perpendicular conveying passage is configured with the sheet conveying speed V ₂ at elevated fixed relationship with respect to the image forming process speed.

First, when a difference m (m = hi) between the paper width dimension h in the transport direction of each transfer sheet and the interval dimension i between the transfer sheets is calculated, A4; m = hi = 297-165 = 132 (Mm) B4; m = hi = 257-190 = 67 (mm) A3; m = hi = 297-233 = 64 (mm) Since the transfer paper having the largest difference m is A4, the paper transport speed is set based on the A4 transfer paper.

As shown in FIG. 10 (c), FIG. 11 (c) and FIG. 12 (c), in the case of A4 horizontal feed (short feed), the transfer paper is a toner image on the drum 601. Is transferred and passes through the fixing device 700, where the toner image is fixed, and then passes through the fixing discharge roller pair 704 and passes through the paper detection sensor 801.
Reach Transfer sheet conveyance speed at this time is set to the low speed side transport speed V ₁ of the same about 250 mm / sec and the process speed, the vertical width in the conveying direction of the transfer sheet as shown in FIG. 10 (c) While the dimension h is 297 mm, the interval i between transfer sheets is about 165 mm. The transfer paper advances through a pair of transport rollers 802, and after passing through a transport roller 804, advances to a turn transport path 823. At this time the gate claw 805
Is displaced to the upper position shown in the figure by a broken line.

When the trailing edge of the transfer sheet is detected by the paper detection sensor 801, the following forward conveying roller group conveying roller 804 is switched to the conveying speed V ₂ of the high-speed side. Fast side conveying speed V ₂ at this time is determined as follows.

First, the distance L1 from the leading edge of the paper to the paper stop position 928 when the paper is detected by the paper detection sensor 801 is the distance La from the fixing roller 701 to the stop position 928 (in this embodiment,
880 mm), length Lt of transfer paper in the transport direction (210 mm for A4 size transfer paper), paper detection sensor 801 from fixing roller 701
L1 = La−Lt−Ls with respect to the distance Ls (110 mm in this embodiment).

Further, the time T2 from the time when the preceding transfer paper P1 is detected by the paper detection sensor 801 to the time when the leading end reaches the stop position 928 is the time Tf at which the subsequent transfer paper P2 catches up with the preceding transfer paper P1, T2 = Tf−Tb−Td, where Tb is the time required for the transfer paper P1 to move in the width direction over the width dimension, and Td is the time at which the trailing end of the preceding transfer paper P1 is detected by the paper detection sensor 801. Become.

On the other hand, the succeeding transfer paper P2
The time Tg to catch up with P1 and the time Th at which the trailing edge of the succeeding transfer paper P2 is detected by the paper detection sensor 801 are as follows: Tg = (La−2 × Lt−Ls) / V ₂ Th = Tc + (Lt + Ls) / V _{1 = i / V 1 + (} Lt + Ls) / V 1 = (i + Lt + Ls) / V 1 become. Then, since Tf is Tf = Tg + Th, Tb = (h + m) / V ₁ Td = Ls / V ₁ and Tf = (La−2 × Lt−Ls) / V ₂ + (i + Lt + Ls) / the V _1. Therefore, T2 (= Tf−Tb−Td) is calculated as follows: T2 = (La−2 × Lt−Ls) / V ₂ + (i + Lt + Ls) / V ₁ − (h + m) / V ₂ −Ls / V ₁ = (La− 2 × Lt−Ls−hm) / V ₂ + (i + Lt) / V ₁ That is, V ₂ = V ₁ × (Lt + h + m) / (i + Lt). At this time, the interval i between the transfer sheets is about 165 mm as shown in FIG.
h = 297 mm, and substituting the actual numerical value in this embodiment for the above equation, V ₂ = 250 × (210 + 297 + 13) / (165 + 210) = 250 × 520/375 = 347 (mm / sec) It is determined.

In the case of A4 horizontal feed, when the trailing edge of the transfer paper is detected by the paper detection sensor 801, each of the transport rollers 804, 813, 92
2,923,924,925,926 is switched from the low conveying speed V ₁ with the conveyance speed V ₂ of the high-speed side. The transfer rollers 923,924,
925,926 have been made to take only the conveying speed V ₂ of the high-speed side.

The transport speed V ₂ on the high speed side obtained as described above (347 m
m / sec), the transfer paper P1
Reaches the stop position 928 after about 2.05 seconds after exiting the fixing roller 701, as shown in FIG. 12 (c).

Then, move to right angle conveyance, and the transfer paper
The evacuation is completed at a position with a margin of about 13 mm with P2.

At this time, 804, 813, 922
So that the trailing edge of the transfer sheet that has been conveyed after passing the roller 922, it is returned to the conveying speed V ₁ of the original low-speed side.

By the way, as described above, the high-speed transfer speed V ₂
Stop position 928 is reached after about 1.61 seconds. Then, the transfer to the right angle conveyance is performed, and after about 2.35 seconds, the retraction is completed at a position having a margin of about 13 mm with the succeeding transfer paper P2. The switching to the right angle direction and the transport operation are the same as in the case of A4.

Further, in the case of the A3 vertical feed (longitudinal feed) shown in FIGS. 10 (a), 11 (a) and 12 (a), the A4 horizontal feed and the B4 vertical feed are also used. A transport operation basically similar to that in the case is performed.

That is, the transfer sheet in this case will be transported at about 250 mm / sec which is the image forming process speed V ₁ and the same conveying speed, when the trailing edge of the transfer sheet is detected by the sheet detection sensor 801, transport rollers 804 the following forward conveying roller group is switched to the high-speed conveying speed V _2. Fast transport speed V ₂ at this time is also set to the same speed 347 mm / sec and a high speed conveying speed V ₂ in the case of when and B4 feeding of the A4 feeding, transfer paper P1 of the preceding, coming out of the fixing roller 701 Later, first
2 As shown in FIG. 2B, the stop position 928 is reached after about 1.61 seconds. Then, the transfer to the right angle conveyance is performed, and after about 2.35 seconds, the retraction is completed at a position having a margin of about 13 mm with the succeeding transfer paper P2.
The switching to the right angle direction and the transport operation are the same as in the case of A4.

Further, in the case of the A3 vertical feed (longitudinal feed) shown in FIGS. 10 (a), 11 (a) and 12 (a), the A4 horizontal feed and the B4 vertical feed are also used. A transport operation basically similar to that in the case is performed.

That is, the transfer sheet in this case will be transported at about 250 mm / sec which is the image forming process speed V ₁ and the same conveying speed, when the trailing edge of the transfer sheet is detected the sheet detection sensor 801, transport rollers 804 or less forward conveying roller group is switched to a high speed conveying speed V _2. Fast transport speed V ₂ at this time is also set to the same speed 347 mm / sec and a high speed conveying speed V ₂ in the case of when and B4 feeding of the A4 feed,
After leaving the fixing roller 701, the preceding transfer paper P1 reaches the stop position 928 after about 1.45 seconds, as shown in FIG. 12 (a). Then, the process proceeds to right angle conveyance, and after about 2.34 seconds, the sheet is completely retracted to a position having a margin of about 13 mm with the succeeding transfer sheet P2. At this time, the switching to the right angle direction and the transport operation are
This is the same as the case of A4 feed and the case of B4 feed. In this way, in the right-angle discharge operation to the sorter, the paper feed speed in the forward transport path is increased at a predetermined timing in a fixed relationship with the process speed. This causes the preceding transfer paper P1 and the subsequent transfer paper P1 in the forward transport path.
When the interval between the transfer paper P2 and the transfer paper P2 is equal to or greater than a predetermined value, the preceding transfer paper P1 is received at the entrance of the right-angled conveyance path, is sent out therefrom, and then the subsequent transfer paper P2 enters the entrance of the right-angled conveyance path. . For this reason, the lap interference state between the preceding recording sheet and the succeeding transfer sheet is reliably prevented at the entrance of the right-angled conveyance path.

That is, as described above, the high-speed transport speed V ₂ is determined from the width direction value h of the transfer paper and the transfer paper interval value i for any transfer paper size, and the same for transfer paper of any size. The interference can be avoided with a sufficient distance, and a good discharging operation is performed.

In the present embodiment, at the above-described transport speed, each transport roller in the forward transport path is set to the same paper transport speed as the image forming process speed, and each transport roller in the right-angle transport path is The paper transport speed that is increased in a fixed relationship with the process speed is set.

Hereinafter, this case will be described using A3 vertical feed (longitudinal feed), B4 vertical feed (longitudinal feed), and A4 horizontal feed (short feed).

First, FIGS. 10 (a) and 11 (a) used for the description of the forward transport speed and FIG. 13 (a) newly added this time
In the case of A3 longitudinal feed (longitudinal feed) shown in FIG. 5, the transfer paper is transferred with the toner image on the drum 601 and passes through the fixing device 700, where the toner image is fixed, and then the fixing discharge roller Pair 704, transport rollers 802, 804, 813, 922, etc. are sequentially passed. The gate claw 805 is displaced to the position shown by the broken line in the figure, whereby the transfer paper is guided to the turn conveyance path 823. The gate claw 814 is located at a position indicated by a solid line in the drawing, and the transfer paper is guided to the turn conveyance path 826.

Transfer sheet conveyance speed at this time is set to the low speed side transport speed V ₁ of the same about 250 mm / sec and an image forming process speed, the paper interval between the transfer sheet to each other is shown in Figure No. 10 (a) About 233mm. Next, the transfer paper reaches the forward transport roller 923, but the following forward transport rollers 923, 924, 925 also have the same speed as the image forming process, about 250 mm / s.
It is set to the low speed side transport speed V ₁ of the ec.

Then, the transfer paper P ₁ passes through the forward conveyance roller 925,
When the leading edge is detected by the sheet detection sensor 927, the leading edge is adjusted to the stop position 928 by the signal, and is temporarily stopped. This is as shown in FIG. 13 (a).
About 1.84 seconds after the trailing end of the paper exits the fixing roller 701, the transfer direction of the transfer paper P1 is changed by 90 °.

The transport speed of the right-angle transport roller 926 is set to about 470 mm / sec, which is faster than the image forming process speed (about 250 mm / sec). As shown in FIG. (A), the transfer paper P1 is about 310 m
The paper is transported at a right angle over m
It is placed in a non-interference position with a margin width of 3 mm.
This is about 2.5 seconds after the trailing edge of the preceding transfer paper P1 has left the fixing roller 701. At this time, the leading end of the succeeding transfer sheet P2 is located between the transfer roller 813 and the transfer roller 922, and the distance between the transfer sheets is about 70 mm.

In this way, the discharge of the preceding transfer paper P1 is completed, but when the speed of the right-angled conveyance is kept at the image forming process speed, the state shown by the broken line in FIG. Interference with the transfer paper P2 will occur.

Next, FIG. 10 (b), FIG. 11 (b) and FIG. 13 (b)
In the case of the B4 vertical feed (longitudinal feed) shown in (2), basically the same paper conveyance is executed as in the case of the above A3 vertical feed (longitudinal feed). That is, each forward transport roller 92
3,924,925 is set to the low speed side transport speed V ₁ of the same about 250 mm / sec and an image forming process speed, after passing through the transfer paper P1 forward conveying roller 925, the leading end is detected by the paper detection sensor 927, The tip is adjusted to the stop position 928 by the signal to stop once. This is about 2.06 seconds after the rear end of the transfer paper P1 has left the fixing roller 701, as shown in FIG.
Converted 90 ゜.

The transport speed of the right-angle transport roller 926 is set to about 470 mm / sec, which is faster than the image forming process speed (about 250 mm / sec). As shown in FIG. (B), the transfer paper P1 is approximately 270 mm
Is transported at right angles over the transfer paper P2
It is placed in a non-interference position with a margin width of mm. This is 2.64 seconds after the trailing edge of the preceding transfer paper P1 has left the fixing roller 701, as shown in FIG. 13 (b). At this time, the leading end of the subsequent transfer sheet P2 is located between the transfer roller 922 and the forward transfer roller 923, and the distance between the transfer sheets is about 45 mm.

In this way, the discharge of the preceding transfer paper P1 is completed. However, when the speed of the right-angled conveyance is kept at the image forming process speed, the state shown by the broken line in FIG. Will cause interference with the transfer paper P2.

Further, in the case of the A4 horizontal feed (short feed) shown in FIGS. 10 (c), 11 (c) and 13 (c), the A3 vertical feed (longitudinal feed) and the B4 vertical feed are also used. Basically, the same paper conveyance is performed as in the case of feeding (longitudinal feeding).
That each forward conveying rollers 923,924,925 is set to the low speed side transport speed V ₁ of the same about 250 mm / sec and an image forming process speed, the transfer paper P1 is passed through the forward conveying roller 925, the leading end by the paper detection sensor 927 Is detected,
The tip is adjusted to the stop position 928 by the signal to stop once. This is about 2.68 seconds after the rear end of the transfer sheet P1 has left the fixing roller 701, as shown in FIG. 13 (c), from which the transfer direction of the transfer sheet is changed by 90 °.

The transport speed of the right-angle transport roller 926 is set to about 470 mm / sec, which is faster than the image forming process speed (about 250 mm / sec). As shown in FIG. (C), the transfer paper P1 is about 310 m.
The paper is transported at a right angle over m
It is placed in a non-interference position with a margin width of 3 mm.
This is about 3.34 seconds after the trailing edge of the preceding transfer paper P1 has left the fixing roller 701. The leading end of the succeeding transfer sheet P2 at this time is between the transport roller 922 and the forward transport roller 923.

The time when the preceding transfer paper P1 substantially exits the right-angled conveyance path is about 3.3 seconds after the rear end of the transfer paper P1 has left the fixing roller 701.
2 is located about 10mm rearward. Therefore, no interference occurs between the two transfer papers. Thus, it can be seen that the transport speed (approximately 470 mm / sec) of the right-angle transport roller 926 is determined based on the A4 horizontal feed with the smallest transfer sheet interval.

In this way, the discharge of the preceding transfer paper 1 is completed. However, if the speed of the right angle conveyance is kept at the image forming process speed, the state shown by the broken line in FIG. Interference with the transfer paper P2 will occur.

In the present embodiment, the following advantages can be obtained by using the sorter configured as described above.

The transfer paper is taken out in the front direction, and the edge of the transfer paper can be brought to the front irrespective of the size of the transfer paper, so that the transfer paper can be easily taken out.

Post-processing such as stapling or punching of the transfer paper edge can be easily performed, and manual operation can be performed.

Even if a jam occurs during sorting, the jammed paper can be easily taken out because the edge of the copy paper is on the front side.

Transfer paper of relatively large size, such as A3 size or B4 size, can be fed in the short direction, so that the transport efficiency is improved and speedy sorting work is possible.

Since the A3 size maximum transfer paper is fed in the short direction and stacked on the bin tray, the width direction of the sorter can be shortened to save space. The width can be further reduced by limiting the number of stacks in the bin and giving the bin a certain angle or more.

Since it can be sequentially added, a large-capacity sorter can be provided that sufficiently satisfies the needs of the user. Even in this case, the transport path of the sorter can be kept short to prevent a decrease in transportability.

(Effects of the Invention) As is clear from the above description, according to the present invention, the recording paper is directed to the finisher in such a manner that the direction of the recording paper is changed from the image forming conveyance path of the front operation type image forming main body in a substantially right angle direction. Since the sorting discharge path is provided, the size of the entire image forming apparatus including the image forming main body and the finisher can be reduced. Therefore, it is possible to make the space extremely small without setting a large operation space around the apparatus which has been required conventionally, and it is possible to install the image forming apparatus in a small space.

In addition to this, according to the present invention, the width direction value h of the recording sheet with the strictest transport conditions is set so that the interval between the preceding recording sheet and the subsequent recording sheet in the forward transport path is made equal to or greater than a certain value. Since the paper feed speed in the forward transport path and the paper feed speed in the right-angle transport path with respect to the paper transport speed in the forward transport path are set based on the paper interval value i, the entrance portion of the right-angle transport path is used. The interference state due to the arbor wrap between the preceding recording sheet and the succeeding recording sheet is reliably prevented by a simple configuration for any size recording sheet. Therefore, high-speed and good paper conveyance can be performed stably and inexpensively.

Further, according to the present invention, since the switchback conveyance path for performing double-sided copying of small-sized recording paper is set in the conveyance path in the image forming main body, both-sided copying of small-sized recording paper is performed. It is possible to shorten the conveyance time until re-feeding the paper, thereby improving the efficiency of the copying operation.

Furthermore, according to the present invention, since the recording paper is reversed in the recording paper transport path including the right-angle transport path, the page order of the recording paper can be made uniform according to the document.

[Brief description of the drawings]

FIG. 1 is a schematic layout view showing the overall configuration of an image forming apparatus provided with a sheet transport mechanism according to an embodiment of the present invention, and FIG. 2 is an automatic reversing original used in the image forming apparatus shown in FIG. Enlarged side view of paper feeder (ARDF), Fig. 3 (a),
(B), (c) and (d) are partially enlarged side views illustrating the configuration and operation of a document feeder, a reversing unit, and a document feeder of the automatic reversing document feeder, and FIG. FIG. 5 is a schematic front view showing a state in which a sorter has been added to the image forming apparatus shown in FIG. 5, FIG. 5 is an enlarged front view showing the configuration and operation of a bin sorter located above the sorter, and FIG. Enlarged front view illustrating the configuration and operation of a bin sorter located below the sorter. FIG. 7 is a schematic front view showing a state in which a sorter is further added to the image forming apparatus shown in FIG. 8 (a) and 8 (b) are enlarged front views for explaining the configuration and operation of the sorter entrance, and FIG. 9 is a perspective view for explaining the main part of the sheet transport mechanism according to the embodiment of the present invention. , FIG. 10 and FIG. 11 show the paper by the paper transport mechanism shown in FIG. FIGS. 12 and 13 are diagrams for explaining the operation of the paper transport mechanism shown in FIG. 9, respectively. C: Copier body, 400: Multi-stage paper feeder (PB), 100
… Automatic reversal document feeder (ARDF), 821 …… Small size switchback conveyance path, 823 …… Synthesis copy conveyance path, 824
…… Switchback conveyance path for large size, 921 …… Sorter conveyance path to constitute right angle direction conveyance path, 923,924,92
5… Forward conveyance roller, 926… Right angle conveyance roller, 923a, 924a, 925a, 926a …… Pinch roller, 1000…
... sorter.

 ──────────────────────────────────────────────────続 き Continued on the front page (31) Priority claim number Japanese Patent Application No. 1-299191 (32) Priority date Hei 1 (1989) November 17, (33) Priority claim country Japan (JP)

Claims (8)

(57) [Claims] A front-operation-type image forming main body having a forward conveyance path for conveying a recording sheet on which an image is formed and discharged toward a front side and a back side; A finisher for post-processing of recording paper arranged side by side with the main body, receiving the recording paper discharged from the forward transport path, transporting the recording paper in a substantially right-angle direction, and feeding the recording paper to the finisher. And a right-angle conveyance path connected to the direction conveyance path, wherein the paper conveyance means in the forward conveyance path and the paper conveyance means in the right-angle conveyance path have a conveyance operation. A sheet transport mechanism for an image forming apparatus, further comprising a common switching mechanism for selectively switching between operation and stop. 2. A forward conveyance path for conveying a recording sheet on which images are formed and discharged at a predetermined image forming process speed toward a front side and a rear side at a predetermined sheet feed speed. A front-operation-type image forming main body, a finisher for recording paper post-processing arranged side by side on the image forming main body, and a recording paper ejected from the forward conveyance path, in a substantially right-angle direction. Transport, a paper transport mechanism of an image forming apparatus comprising a right-angle transport path connected to a forward transport path so as to feed the recording paper to the finisher, wherein the paper transport means in the forward transport path includes: together and is configured to allow selecting either enhanced paper conveying speed V ₂ at a fixed relationship with respect to the image forming process speed and the same paper conveyance speed V ₁ and the image forming process speed, Up The paper feeding means in the forward transport path sets the paper transport speed based on the recording paper having the largest difference (hi) between the paper width dimension h in the transport direction of the recording paper and the interval dimension i between the recording papers. A sheet transport mechanism of the image forming apparatus, wherein 3. A paper transport mechanism according to claim 2, wherein the paper transport means in the forward transport path adjusts the paper transport speed by a signal for detecting the trailing edge of the recording paper immediately after leaving the fixing device. A sheet transport mechanism of the image forming apparatus configured to be set. 4. A paper transport mechanism of the image forming apparatus according to claim 2, the paper feeding means in the forward conveying path, along which is configured with an image forming process speed and the same paper conveyance speed V ₁ , the paper feeding means in a direction perpendicular the conveying path, the sheet conveying mechanism of the image forming apparatus is configured to include a sheet conveying speed V ₂ at elevated fixed relationship with respect to the image forming process speed. 5. A paper transport mechanism according to claim 2, wherein the paper feeding means in the forward transport path performs recording based on a paper width dimension h of the recording paper and an interval dimension i between the recording papers. A sheet conveying mechanism of an image forming apparatus configured to set a sheet conveying speed for each sheet size. 6. A conveying direction of a recording sheet is set from a front side to a rear side with respect to an operation surface of a copying machine, and a conveying path for conveying and circulating in the conveying direction is provided. A sheet conveying mechanism of an image forming apparatus equipped with a discharge port for the recording sheet on one of an upper surface of the copying machine and a side of the copying machine corresponding to a direction perpendicular to the conveying direction; A small-size switchback conveyance path, which is provided immediately downstream of the fixing device in the direction and is provided separately from the discharge port on the upper surface side and sets a conveyance path to the refeeding device for duplex copying; A large size, which is located downstream of the small size switchback conveyance path in the path and branches from the discharge path toward the discharge port on the upper surface of the copying machine to set the conveyance path toward the double-sided copy refeeding device. A switchback transport path; a composite copy transport path for setting a transport path branching from the discharge path toward the discharge port on the upper surface of the copying machine toward the double-sided copy refeeding device; A right-angle conveyance path that branches from a conveyance path set for two-sided copying and composite copying and that changes the conveyance direction of the recording paper to a right-angle direction at a position different from the refeeding device for two-sided copying. A sheet transport mechanism of the image forming apparatus. 7. The image forming apparatus according to claim 5, wherein the recording sheet is formed between the image forming photosensitive member and the image forming photosensitive member in a conveying path from the near side to the far side with respect to the operation surface. The transfer speed of the recording paper during the transfer process is V ₁
And the transport speed of the recording paper during the other copy processes.
When set to V _2, the paper transporting mechanism of the image forming apparatus is set a relation between V ₁ <V _2. 8. A sheet feeding mechanism for an image forming apparatus according to claim 5, wherein said sheet feeding mechanism branches off from a feeding path set for double-sided copying and composite copying of large-size recording paper. Is located on an extension of a right-angled conveyance path that converts the conveyance direction of the recording paper into a right-angled direction at a different position,
A sheet conveyance mechanism of an image forming apparatus, comprising: a reversing storage section for storing a recording sheet conveyed from the right-angled conveyance path in a state in which the image surface of the recording sheet is switched in an image surface direction.