JP2003122073A - Sheet carrying device and image forming device equipped with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet carrying device capable of smoothly carrying a sheet remaining on a carrying path without damaging an image forming part installed in an image forming device, especially, in the case that a sheet jamming occurs in the device, and to provide the image forming device equipped with the sheet carrying device. SOLUTION: The carrying route is characterized in that the sheet lying in either of a 1st or 2nd carrying path is discharged with priority when a sheet carrying operation is restarted after the interruption, thereafter, the sheet lying in the other path is discharged.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet conveying apparatus and an image forming apparatus, and more particularly, when a sheet jam occurs in the apparatus, an image forming unit provided in the apparatus is damaged. It is an object of the present invention to convey a sheet that should be smoothly processed on the sheet remaining on the conveyance path without any trouble.

[0002]

2. Description of the Related Art Generally, in an image forming apparatus such as a copying machine or a printer, a sheet conveying route from a sheet feeding section to an image forming section and a sheet discharging section is designed to be short in order to reduce jam of the sheet. Has been done.

[0003]

By the way, in the well-known jam processing, first, the sheet causing the jam is removed from the conveying path. Next, the sheet remaining on the transport path is discharged. Here, as one of the features of the image forming apparatus, in order to improve the throughput of the sheet, it is necessary to provide durability, and the apparatus itself tends to be large. Further, when an image is formed on the front and back surfaces of the sheet, the sheet has to pass through two image forming units.

Therefore, in the above-mentioned apparatus, the conveyance path becomes long, and therefore, even if the sheet causing the jam is removed from the conveyance path, the jam is likely to occur again. Further, when the sheet remaining on the conveyance path is discharged, the sheet having the image formed on the front surface of the sheet is passed to the image forming unit which forms the image on the rear surface thereof. It causes damage and shortens the life.

The present invention has been made in view of the above problems, and it is possible to reduce the occurrence of jams and extend the life of the image forming section, and a sheet conveying apparatus including the same. The challenge is to provide.

[0006]

In order to solve the above problems, a sheet conveyed to a common entrance conveyance path is distributed to a first or second path, and the sheet is fed from each of the paths to a common discharge path. In a sheet conveying device having a conveying route for discharging through, the conveying route preferentially discharges a sheet in either the first or second path when the conveyance of the sheet is interrupted and restarted, and then It is characterized in that the sheet on the other path is discharged.

An image forming apparatus having a conveyance route for allocating a sheet conveyed to a common entrance conveyance path to a first or second path and discharging the sheet from each of the paths through a common discharge path. In the above, in each path, an image forming unit that forms an image on the surface of the sheet is provided, and the transportation route is a sheet having either one of the first or second paths when the transportation of the sheet is interrupted and restarted. Is preferentially discharged, and then the sheet on the other path is discharged.

Further, as a concrete example of the image forming section,
An electrophotographic system having an image bearing member and a transfer unit, an inkjet system having an ink tank unit and a recording head, and a thermal system are used.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings. 1 and 2 are schematic views of an image forming apparatus to which the sheet conveying apparatus of the present invention is applied. The image forming apparatus 1 includes a sheet feeding unit 10 that sequentially conveys sheets to a main body unit 20, a main body unit 20 that forms an image on the sheet, and a discharge unit 30 that discharges the sheet on which the image is formed to the outside.
It is composed of a transport route for transporting the sheet to the paper feed unit 10, the main body unit 20, and the discharge unit 30. In this embodiment, the paper feed unit 10 is located upstream and the discharge unit 30 is
To the downstream.

The sheet feeding section 10 has a stacker 11 on which sheets are stacked, and a conveyor belt (not shown) having a suction means for picking up the uppermost one sheet from the stacker 11. A friction method such as a scraper method may be used instead of the suction means. Furthermore, the stacker 11 is provided in several stages, and each stacker 1
In 1 is stacked sheets cut into a desired size.

The main body section 20 also has an image forming section 21. The image forming unit 21 has a configuration using an electrophotographic method, and is provided with an image forming unit 22 and a fixing unit 23. Further, it has two image forming sections 21 for copying or recording images on both sides of the sheet. Here, the image forming unit 21 that forms an image on one surface of the sheet is a first image forming unit 21a, and the image forming unit 21 that forms an image on the other surface of the sheet is a second image forming unit 21b. The incidental items are also divided into the first and the second.

In this embodiment, as described above, the two image forming sections 21 are provided, but the image forming section 2
1 may be provided for each of cyan, magenta, and yellow (and black). Furthermore, although the image forming unit 21 discloses a configuration using an electrophotographic system, it may be applied to an inkjet system and a thermal system.

The image forming section 22 is conventionally known in which a device for charging, exposing, developing, transferring, discharging, cleaning and discharging is arranged around an image carrier 24 carrying an electrostatic latent image. . Specifically, after an electrostatic latent image is formed on the image carrier 24 and visualized by a developer, the visualized image is transferred onto a sheet and then passed through the fixing unit 23. ,
The developer is fixed on the sheet. The fixing unit 23 includes a fixing roller 231 and a pressure roller 232.
A heat source such as a surface heating heater or a halogen heater is provided inside 31.

As the developer, either one component or two components consisting of toner and carrier may be applied,
Further, either magnetic or non-magnetic may be applied.
Further, the transfer unit 25 is shown as a belt type, but a roller type or a corona type may be used.

The conveyance route P is composed of an entrance conveyance route P1, a branch route P2 provided with a switching unit 40, and a discharge route P3 for outputting a sheet after image processing. Approach conveyance path P1
Is a common path that the sheet always passes once when the sheet is conveyed from the paper feed unit 10 to the discharge unit 30. In this embodiment, the entrance conveyance path P1 is a path from the paper feed section 10 to the front of the branch path P2 via the first image forming section 21a.

The branch path P2 is a path for allocating the sheet conveyed from the entrance conveyance path P1 to the first path P21 or the second path P22, and this allocation is performed by the switching section 40. Here, the first route P21 is
This is a path for transporting the sheet from the first image forming unit 21a to the discharge unit 30 when an image is formed on only one surface of the sheet. The second path P22 is a path for forming an image on one surface of the sheet and then forming an image on the other surface of the sheet, and the second image forming unit 2
1b is provided.

The fixing unit 23 of the first image forming unit 21a is provided between the point after the image is formed by the first image forming unit 21a and the point before the image is formed by the second image forming unit 21b. It has a length that releases the heat accumulated in the sheet when the sheet is fixed. As a result, the second image forming unit 21b is not affected by the heat accumulated in the sheet, the life of the second image forming unit 22b can be extended, and a good image can be formed on the other surface of the sheet. Can be formed.

Further, on the conveying route P, the detecting means 6
0 and driving means 70 are provided at appropriate positions.
The detection unit 60 detects whether or not a sheet remains on the conveyance route P, and is a micro switch, a photo interrupter, a reflection type sensor, or the like.

The location where the detection means 60 is provided is a location where sheet jamming is likely to occur, and is specifically as follows. In the approach conveyance path P1, each stacker 11
60a at which the sheets are separated from each other, 60b after the paths of the stackers 11 merge, and 60 in front of the first image forming unit 21a.
c, between the first image forming unit 22a and the first fixing unit 231a, after the first fixing unit 231a and the first fixing (60e, 60
f).

In the branch path P2, before and after the curved path (60g, 60h, 60l), 60i before the second image forming section 21b, the second image forming section 22b and the second fixing. The second fixing portion 23 (60j, 6) between the portion 231b.
0k). In particular, since the detection unit 60 provided on the second path P22 forms an image on the other surface of the sheet, the distance becomes longer than that of the first path P21.
It is arranged according to the size of the sheet forming the image (60 m). For example, if the sheet size is A2,
It is possible to fit at least two within the size. Next, the discharge unit 30 is provided 60n before and after the curved path, and 60O near the sheet outlet.

The driving means 70 is a motor, specifically DC
A motor, which is provided in the paper feed unit 10, the main body unit 20, and the discharge unit 30, respectively. The drive means 70 of the main body portion 20 includes a first motor portion 70b1 and a second motor portion 70b2.
And a third motor portion 70b3.

FIG. 3 is a schematic diagram in which each drive means drives the transport route P. The driving means 70 a of the paper feeding unit 10 is responsible for driving the path PA of the paper feeding unit 10. First motor unit 70b1
Is from the front of the path of the main body 20 to the rear PB of the first image forming unit 22a and from the rear of the first image forming unit 22a to the first fixing unit 23.
a Be responsible for the range of the back PC. The second motor portion 70b2 starts from the front and rear PEs of the second fixing portion 23b and an appropriate position of the second path P22 on the side of the second fixing portion 23b from the second fixing portion 23b.
Is responsible for driving the PF behind. Third motor unit 70
b3 is from the appropriate position of the second route P22 to the second route P
It is responsible for driving the appropriate position of the second path P22 and the front / rear PH of the switching unit 40 after the PG and the switching unit 40 merged with each other.

Although not shown, the control means 50 transmits the drive before and after the switching unit 40 and from the rear of the switching unit 40 to the first path P21. Detection means 6
0, the drive means 70 and the switching unit 40 are connected to the control means 50.

As shown in FIG. 4, the control means 50 controls the device by a CPU 51 for instructing the device to control, a ROM 52 (read only memory) in which a program for controlling the device is written. RAM 53 (random access memory) for temporarily storing data necessary for performing the operation, and timer 5 for measuring the operation time of the device
4 is provided. The CPU 51 is connected to the ROM 52, the RAM 53, the timer 54, and each unit of the apparatus via a bus such as a data bus. The detecting unit and the detecting unit 60 are connected to the CPU 51 via the interface unit 55.

FIGS. 5, 6, 7, 8, 9 and 10 show flowcharts of sheet conveyance after sheet jamming in the present invention. First, when a sheet jam occurs on the transport route P (step 1), the sheet causing the jam is removed (step 2). Next, the CPU 51 checks whether or not the operation of checking the transport path is ready (step 3).

The state in which the checking operation of the conveying path can be performed is to ensure the safety of the user as compared with the conventional case and prevent the trouble from occurring when the sheet is conveyed and the apparatus is operated again. is there. For example, whether or not all the doors of the apparatus are closed, whether or not the temperatures of the first fixing unit 23 and the second fixing unit 23 are equal to or higher than the temperature at which the toner is not offset, and the like.

Next, the driving means 70c of the discharging section 30 is driven (step 4). Next, it is checked whether or not the state of the driving means 70c of the discharging section 30 is normal (step 5).

In this check, if the sheets are jammed or if the sheets are conveyed in a double-fed state, the driving means 70c of the discharging section 30 is overloaded, and as a result, the driving means 70c of the discharging section 30 stops. , Or the synchronization is lost, the detection of the synchronization is utilized. The detection of the synchronism is a time sufficient for the rotation of the driving means 70c of the discharging section 30 to be stable, and the timer 54 measures this time.

When there is a synchronization deviation, the CPU 51 determines that the state of the driving means 70c of the discharging section 30 is abnormal, and outputs the fact to an output means (not shown) (step 6) to perform sheet processing. The subsequent sheet conveyance ends midway. When it is determined that the state of the driving means 70c of the discharge section 30 is normal, it is checked whether a sheet jam has occurred on the path of the discharge section (step 7). If the sheet is jammed, the process proceeds to step 6 and the sheet conveyance after the sheet processing is ended halfway.

If the sheet is not jammed, steps 5 and 7 are repeated until the sheet passes for a certain time (step 6). The certain time period means a time period when the sheet at the position closest to the main body unit 20 on the path PI of the discharging unit 30 starts to move. During this time, the sheet on the path of the discharge unit 30 is conveyed to the outside.

After this, the flow from step 5 to step 8 will be referred to as a check routine, and the check routine will be executed each time the driving means of each part is driven and each time the drive is transmitted from the driving means to each of the divided conveyance routes.

Next, the CPU 51 causes the switching section 40 to switch the sheet conveyance to the second path P22 (step 9). This limits the sheet conveyance route P between the second route P22 and the route PI of the discharge unit 30.

Next, the third motor portion 70b3 is driven (step 10), and this drive is transmitted from an appropriate position of the second path P22 to the range of FH after the second path P22 is merged (step 12). ). A check routine is executed in each of steps 10 and 12 (steps 11 and 13). Meanwhile, the second path P2
The sheet on the area of PG after joining the second path P22 from the appropriate position 2 is conveyed to the outside through the path of the discharge unit 30.

Next, the second motor portion 70b2 is driven (step 14), and the check routine is executed (step 15). After that, this drive is sequentially performed for the second fixing unit 2
It is transmitted from an appropriate position of the second path P22 on the 3b side to the PF behind the second fixing unit 23b and the front and rear PEs of the second fixing unit 23b (steps 16, 18, 20), and in each step, a check routine is performed. (Step 1
7, 19, 21). During this time, the sheet on the range of the rear PD of the second image forming unit 22b from the appropriate position of the second path P22 on the second fixing unit 23b side is conveyed to the outside.

Next, drive the third motor section 70b3
After the switching unit 40, it is transmitted to an appropriate position on the second path P22 and the front and rear PH of the switching unit 40 (steps 22 and 24),
Perform a check routine at each step (Step 2
3, 25). In the meantime, from the front of the switching unit 40 to the switching unit 40
The sheet on the range of the appropriate position of the first path P21 on the side passes through the second path P22 formed by the switching unit 40,
It is transported to the outside.

Next, the second motor section 70b2 is stopped (step 26), and the switching section 40 switches the sheet conveyance from the second path to the first path P21 (step 27). Enter the transport route P to enter the transport route P1 (paper feed unit 10
And the first image forming unit 21a), the first path P2
1 and the discharge unit 30 so that the sheet on the first path P21 does not enter the second path P22.

Next, the first motor section 70b1 is driven (step 28), and the check routine is executed (step 29). After that, this drive is transmitted in order from the rear of the first image forming unit 22a to the rear of the first fixing unit 23a and the path of the main body unit 20 to the rear PB of the first image forming unit 22a (step 30, 32), in each step, a check routine is executed (steps 31, 33). During this time, the sheets on the range from the front of the path of the main body unit 20 to the rear of the first fixing unit 23a are conveyed to the outside.

Further, the driving means 70a of the sheet feeding section 10 is driven (step 34), and this driving is transmitted to the path PA of the sheet feeding section 10 (step 36). At each step, a check routine is executed (steps 35 and 3).
7). During this time, the sheet on the path of the sheet feeding unit 10 is conveyed to the outside. Then, the sheet feeding unit 10, the first motor unit 70b1, and the driving unit 70 for writing in the discharge unit 30 are sequentially stopped (step 38), and the sheet conveyance after the sheet processing is completed.

[0039]

As described above, according to the present invention, the sheet existing in one of the first and second paths is preferentially discharged, and then the sheet in the other path is discharged. Thus, it is not necessary to pass the discharged sheet through the first and second paths, and it is possible to reduce the occurrence of jam.

Further, an image forming unit is provided in each of the first and second paths, the sheet existing in either one of the first and second paths is preferentially discharged, and then the sheet in the other path is discharged. With the configuration for discharging, it is not necessary to pass the sheet remaining on the conveyance route to another image forming unit after the jam processing, so that the life of the image forming unit can be extended.

[Brief description of drawings]

FIG. 1 is a schematic diagram of an image forming apparatus to which a sheet conveying apparatus of the present invention is applied.

FIG. 2 is a diagram showing an example of an arrangement of detection means in a schematic view of an image forming apparatus to which a sheet conveying device of the present invention is applied.

FIG. 3 is a schematic diagram in which each drive unit drives a transport route.

FIG. 4 is a diagram showing a schematic block of control means.

FIG. 5 is a diagram showing a flowchart of sheet conveyance after sheet processing.

FIG. 6 is a view showing a continuation of the flowchart of FIG.

FIG. 7 is a view showing a continuation of the flowchart of FIG.

FIG. 8 is a view showing a continuation of the flowchart of FIG.

FIG. 9 is a view showing a continuation of the flowchart of FIG.

FIG. 10 is a view showing a continuation of the flowchart of FIG.

[Explanation of symbols]

1 Image forming device 10 Paper feeder 20 body 30 discharge part 40 switching unit 50 control means 60 Detection means 70 Driving means P transport route

Claims (6)

[Claims] 1. A sheet conveying device having a conveying route for distributing a sheet conveyed to a common entrance conveying path to a first or second path and discharging the sheet from each of the paths through a common discharge path. In the conveyance route, when the conveyance of the sheet is interrupted and restarted, the sheet in either the first path or the second path is preferentially ejected, and then the sheet in the other path is ejected. A sheet conveying device characterized by: 2. An image forming apparatus having a conveyance route for distributing a sheet conveyed to a common entrance conveyance path to a first or second path and discharging the sheet from each of the paths through a common discharge path. In the entrance conveyance path and the first or the second path, an image forming unit that forms an image on a sheet surface is provided, and the conveyance route is, when the conveyance of the sheet is interrupted and restarted, An image forming apparatus characterized in that a sheet in one of the first and second paths is preferentially discharged, and then a sheet in the other path is discharged. 3. The image forming apparatus according to claim 2, wherein the sheet is preferentially discharged from a sheet near the discharge path. 4. The image forming apparatus according to claim 2, wherein the image forming unit is constituted by an electrophotographic system having an image carrier and a transfer unit. 5. The image forming apparatus according to claim 2, wherein the image forming unit is configured by an inkjet method having a recording head including an ink tank. 6. The image forming apparatus according to claim 2, wherein the image forming unit is configured by a thermal system having a thermal head.