JP2001261212A - Sheet post-treating device and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet post-treating device capable of restraining a jam due to sheet curl and keeping the discharged sheet grade from being impaired by curl restraining, and an image forming apparatus using it. SOLUTION: This sheet post-treating apparatus for discharging and treating a sheet on which an image is formed by an image forming apparatus body is provided with an air feeding port 62 for applying air from a sheet cooling fan 59 provided in the image forming apparatus body to a transported sheet.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet post-processing apparatus for discharging a sheet on which an image is formed by an image forming apparatus, and an image forming apparatus to which the sheet post-processing apparatus can be attached.

[0002]

2. Description of the Related Art In recent years, an image forming apparatus and a color image forming apparatus capable of high-speed output of several tens or more sheets per minute have begun to be put into practical use. In such an apparatus, for example, in a color image forming apparatus, yellow, magenta, cyan,
A method of forming a full-color image by superimposing black toners of four colors and melting and mixing the toners by a heat roller fixing device is adopted.

Further, a sheet post-processing apparatus for processing sheets discharged from an image forming apparatus according to the needs of a user, such as a sorter for arranging output sheets in a desired number of copies, a staple or a punch, a large number of stacks, and the like. There is also a growing demand for post-processing devices such as finishers that enable it. In particular, in the case of printers, there is an increasing demand for a model that can selectively use a function of back-side paper discharge in which an image is discharged downward.

[0004] In these sheet post-processing apparatuses, compared to the conventional method of stacking on a discharge tray as usual,
It is easily affected by the size and orientation of the sheet curl. If the sheet curl is too large, problems such as improper stacking in the post-processing device, improper alignment, and stapling are likely to occur.

As shown in FIG. 7, in order to remove the sheet curl from the sheet discharge port of the image forming apparatus and to suppress the curl growth with the speeding up and color formation of the image, the discharge roller 100 is used. Conventionally, the sheet discharged to the discharge tray 101 outside the apparatus is cooled by blowing air by a sheet cooling blower 102.

[0006]

However, when a sheet post-processing apparatus is attached to an image forming apparatus, the post-processing apparatus itself may not have a sheet cooling and blowing device for removing curl and suppressing curl growth.

If the sheet post-processing apparatus itself does not have a sheet cooling air blower for removing sheet curl and suppressing curl growth, cooling cannot be performed in time with natural cooling due to the increase in speed, and jam occurs due to sheet curl. There was a case.

[0008] When the amount of toner increases along with colorization, the curl of the sheet tends to increase, which causes an increase in the jam rate. Even if the paper is ejected without a jam, the quality of the discharged sheet may be significantly impaired due to the curl of the discharged sheet.Furthermore, due to the heat given by the heat roller fixing device, the sheet cannot be completely cooled, and the discharged sheets may In some cases, the phenomenon of sticking occurred.

In order to solve the above-mentioned problem, a post-processing apparatus for removing sheet curl and suppressing curl growth is provided.
There is a configuration in which a sheet cooling blower dedicated to a post-processing device is provided. According to this, it is possible to suppress a sheet jam which is a problem in a case where the air blowing means is not mounted, and a problem that the output sheet quality is significantly impaired due to the curl of the discharged sheet.

Here, during the sheet jam processing, the post-processing apparatus is detachable from the image forming apparatus. In order to reduce the space for attaching / detaching (moving) the post-processing device during jam processing, it is necessary to reduce the weight and size of the post-processing device.

However, if a dedicated sheet cooling device is attached to the post-processing device as described above, problems such as sheet jams can be solved, but the device cannot be reduced in weight and size, which leads to an increase in cost for the mounting device. In addition, the noise of the cooling device also becomes a problem.

SUMMARY OF THE INVENTION An object of the present invention is to provide a sheet post-processing apparatus which suppresses a jam due to sheet curl and does not impair the quality of a discharged sheet by curling, without increasing the cost and the size of the apparatus. An apparatus is provided.

[0013]

In order to achieve the above object, a typical configuration according to the present invention is a sheet post-processing apparatus for discharging a sheet on which an image has been formed by an image forming apparatus main body. It is characterized by having ventilation means for applying air from a blowing means provided in the apparatus main body to a sheet to be conveyed.

In the above configuration, the air from the air blowing means provided in the main body of the image forming apparatus hits the sheet conveyed through the post-processing device through the air blowing means, so that the sheet is cooled and the curl is generated. Is suppressed. Further, since it is not necessary to provide a sheet cooling fan or the like in the sheet post-processing apparatus, there is no increase in cost and size of the apparatus.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [First Embodiment] Next, a sheet post-processing apparatus according to an embodiment of the present invention and an image forming apparatus equipped with the same will be specifically described with reference to the drawings. FIG. 1 is a schematic cross-sectional view of an image forming apparatus equipped with a sheet post-processing apparatus, and FIGS. 2 to 5 are diagrams illustrating a cooling configuration of a sheet discharged by the sheet post-processing apparatus.

{Overall Configuration of Image Forming Apparatus} First, the overall configuration of the image forming apparatus will be described. In this embodiment, a color image forming apparatus is illustrated.

As shown in FIG. 1, the color image forming apparatus A of the present embodiment has two cassette paper feeding units 1 and 2 and one manual paper feeding unit 3. , 2,
3, the sheet S is selectively fed.

In each of the sheet feeding units 1, 2, 3, the sheets S stacked on the cassettes 4, 5 or the tray 6 are sequentially fed out by the pickup roller 7 from the top sheet. Then, the sheet S fed out by the pickup roller 7 is separated only by the separation roller pair including the feed roller 8a and the retard roller 8b, and is sent to the registration roller pair 12 which has stopped rotating.

In this case, the sheet S fed from the cassettes 4 and 5 whose distance to the registration roller pair 12 is long is relayed to the plurality of conveyance roller pairs 9, 10, and 11 and sent to the registration roller pair 12. By forming a loop, the skew state is corrected.

Downstream of the registration roller pair 12, a sheet S
Transport belt (endless belt) that transports by suction
13 is installed in a substantially horizontal state. The conveyor belt 13 rotates counterclockwise. And this conveyor belt 13
Photoreceptor drums 14, 15, 16, and 17 carrying color toner images of different colors are sequentially arranged along the sheet conveying direction.

Here, the photosensitive drum 14 in the most upstream image forming section M carries a magenta toner image, and the photosensitive drum 15 in the next image forming section C carries a cyan toner image. The photoconductor drum 16 in the image forming section Y carries a yellow toner image, and the most downstream image forming section B
The photoconductor drum 17 carries a black toner image.

In the color image forming apparatus A, a plurality of documents (not shown) are sequentially set at predetermined positions on a document table (platen glass) 19 by an automatic document feeder 18. Then, an image of a document set on the document table 19 (here, a color image) is read by the reading optical system 20. The reading optical system 20 includes a light source 20a for irradiating the original, a CCD element 21 for receiving the reflected light from the original and converting it into an electric signal, and a CCD element 21 for reflecting the reflected light from the original.
, A mirror unit 20b and a lens unit 20c. The read color image is separated into magenta, cyan, yellow, and black color components, and is temporarily stored in an image memory (not shown).

Image information stored in the image memory is sequentially rotated clockwise for each color component by a writing optical system 22 including a polygon mirror 22a including a laser unit and a mirror unit 22b (not shown). The image is written on the photosensitive drums 14, 15, 16, and 17 to form an electrostatic latent image on the photosensitive drum 14. The electrostatic latent images are sequentially visualized by color toners supplied from the respective developing units 23, 24, 25, 26.

Incidentally, the primary chargers 27, 28, 29, 30 for uniformly charging the photosensitive drums 14, 15, 16, 17 and the photosensitive drums 14, 15, 16, 17 after the transfer of the toner image. The cleaners 31, 32, 33, 34, etc. for removing the toner adhering thereon are provided.

The registration roller pair is synchronized with the image formation.
The sheet S sent from the conveyor belt 12 to the conveyor belt 13 is conveyed downstream, and the respective photosensitive drums 14, 15, 16, 17
And the transfer portions of the transfer chargers 35, 36, 37, and 38, the magenta, cyan, yellow, and black toner images are transferred and superimposed on the sheet surface.

The sheet S that has passed through the transfer section between the lowermost photosensitive drum 17 and the transfer charger 38 is sent to the fixing roller pair 39 by the conveyor belt 13 and passes through the nip of the fixing roller pair 39. In the process, the transferred toner image is fixed on the sheet surface by heating and pressing.

The sheet S, which has been subjected to the fixing process and has passed through the fixing roller pair 39, is sent to the discharge roller pair 41 by the transport roller pair 40, and is discharged outside the image forming apparatus by the discharge roller pair 41.

{Sheet Post-Processing Apparatus} In the image forming apparatus A of the present embodiment, a sheet post-processing apparatus for arranging output sheets in a desired number of sheets, a stapler, a punch, and the like can be detachably mounted. ing. FIG. 1 shows an example in which a sorter as a sheet post-processing apparatus B is mounted.

The sheet post-processing apparatus B has a post-processing apparatus lock 50 as a mounting means, and is attached to the image forming apparatus by a post-processing apparatus lock receiver 51 mounted on the image forming apparatus. It is detachable and movable.

The sheet post-processing apparatus B has a conveyance guide for receiving the sheet discharged by the discharge roller pair 41 of the image forming apparatus A.
52, a discharge roller pair 54 for discharging the sheet guided by the transport guide 52 to the sort bin 53,
And a switching flapper 56 for switching the discharge to the post-processing device discharge tray 55.

The sheet S, which has been subjected to the fixing process and has passed through the fixing roller pair 39 of the image forming apparatus, is sent to the discharge roller pair 41 by the transport roller pair 40, and is transferred to the sheet post-processing device B by the discharge roller pair 41.

The fixed sheet S transferred to the post-processing device B by the pair of discharge rollers 41 passes over the conveyance guide 52, and the post-processing device discharge tray 55 or a sort bin 53 for organizing the sheets into a desired number of copies. Transported to

When the post-processing device discharge tray 55 is selected,
The conveyance path on the side of the paper output tray conveyance guide 57 is selected by the sheet direction switching flapper 56, and the sheet S passes over the paper output tray conveyance guide 57, and the post-processing device paper ejection tray roller pair.
By 58, the sheet is discharged to the post-processing device discharge tray 55.

On the other hand, when the sort bin 53 is selected, the sort bin transport guide 52 is selected by the sheet direction switching flapper 56, and the sheet S is placed in the sort bin transport guide.
The sheet passes through the upper portion 52 and is discharged to the sort bin 53 by the sort bin discharge roller pair 54.

{Sheet Cooling Configuration} The sheet sent to the sheet post-processing apparatus B is likely to curl because it is heated when passing through the fixing roller pair 39. Therefore, in the present embodiment, the sheet sent to the sheet post-processing apparatus B is configured to be cooled. Next, the configuration for that will be described with reference to FIGS. 2 is an explanatory view of the flow of air by the sheet cooling fan, FIG. 3 is an explanatory view of the sheet cooling fan viewed from the sheet post-processing apparatus side,
FIG. 4 is an explanatory view of a duct of a sheet cooling fan portion, and FIG. 5 is an explanatory view of an air supply port provided in a conveyance guide of the sheet post-processing apparatus.

As shown in FIGS. 1 and 2, a sheet cooling fan 59 as a blowing means is provided in the vicinity of the sheet discharge port in the image forming apparatus, and a discharge section cover 60 which forms a side surface of the image forming apparatus. Is provided with an inlet 60a and an outlet 60b (see FIG. 3). Then, as shown in FIG. 4, cooling that guides the air flow so that the air blown out from the air outlet 59 a of the sheet cooling fan 59 extends over the entire outlet 60 b having substantially the same width as the sheet width and does not leak to other parts. A fan duct 61 is provided.

The sheet cooling fan 59 of the image forming apparatus
As a result, air introduced from outside the apparatus is guided to the cooling fan duct 61 as shown in FIG.

Here, the sort bin transport guide 52 is shown in FIG.
As shown in (a plan view of the sort bin transport guide 52), at least one or more air supply ports 62 are provided as ventilation means for sending air onto the transport path.

Therefore, the air flow from the sheet cooling fan 59 of the image forming apparatus guided to the lower surface of the sort bin transport guide 52 passes through the air supply port 62 of the sort bin transport guide 52 disposed on the sheet transport surface. The lower surface of the conveyed sheet S is cooled. Therefore, it is possible to prevent the discharged sheet from curling, and it is possible to prevent a jam caused by the curling. Further, since the sheet cooling fan 59 is provided on the image forming apparatus A side and not provided on the sheet post-processing apparatus B side,
The sheet post-processing apparatus does not increase in size and does not increase in cost.

[Other Embodiments] In the above-described embodiment, an example is shown in which the air flow for cooling the sheet is applied from the lower side of the discharged sheet. However, the sheet cooling fan 59 and the intake port 60a described above are used. , Outlet 60b, cooling fan duct
A similar effect can be obtained by providing a blowing means having the structure of 61 above the sheet conveying path near the discharge port and applying airflow from above. Further, as shown in FIG. 6, by providing the air blowing means on both the upper and lower sides of the sheet conveying path near the discharge port and applying the air flow from both sides of the discharge sheet, it is possible to apply the air flow from one side. Further effects can be obtained.

The transport speed of the discharge roller pair 54 is set slightly higher than the transport speed of the discharge roller pair 41 by the discharge roller pair 41 and the discharge roller pair 54 for transporting the sheet S on the sheet post-processing apparatus side. In this way, the seat cooling fan
By applying the airflow from 59, the sheet can be cooled while the sheet S is being tensioned.
In this case, a higher curl suppressing effect on the sheet can be obtained.

In each of the above-described embodiments, the case where each of the embodiments is implemented alone is shown as an example. However, these embodiments may be implemented not only alone but also in appropriate combinations.

In the above-described embodiment, a sorter is used as a post-processing device. However, the present invention is not limited to this. For example, another post-processing device such as a finisher may be used. The same effect can be obtained by applying the present invention to a sheet post-processing apparatus.

In the above-described embodiment, a copying machine is exemplified as an image forming apparatus. However, the present invention is not limited to this. For example, other image forming apparatuses such as a printer and a facsimile apparatus may be used. The same effect can be obtained by applying the present invention to the image forming apparatus.

In the above-described embodiment, a full-color image forming apparatus is exemplified as an image forming apparatus. However, the present invention is not limited to this, and may be, for example, a monochrome color image forming apparatus. Similar effects can be obtained by applying the present invention to an image forming apparatus.

[0046]

The present invention is constructed as described above.
Since the air from the blower provided in the main body of the image forming apparatus hits the sheet conveyed through the post-processing device via the ventilator, the sheet is cooled, and the occurrence of curl and the accompanying jam are suppressed. Also, since there is no need to provide a special sheet cooling fan or the like in the sheet post-processing device,
There is no increase in cost or size of the apparatus.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional explanatory view of an image forming apparatus equipped with a sheet post-processing apparatus.

FIG. 2 is an explanatory diagram of a flow of air by a sheet cooling fan.

FIG. 3 is an explanatory diagram of a part of a sheet cooling fan as viewed from a sheet post-processing apparatus side.

FIG. 4 is an explanatory view of a duct in a seat cooling fan portion.

FIG. 5 is a diagram illustrating a cooling configuration of a sheet discharged by a sheet post-processing apparatus.

FIG. 6 is an explanatory diagram of an embodiment for cooling both sides of a sheet.

FIG. 7 is an explanatory diagram of a conventional technique.

[Explanation of symbols]

 A: image forming apparatus B: sheet post-processing apparatus S: sheets 1, 2, cassette feeder 3 manual feeder 4, 5, cassette 6, tray 7, pickup roller 8a, feed roller 8b, retard roller 9, 10, 11… Conveying roller pair 12… Registration roller pair 13… Rot 14, 15, 16, 17… Photosensitive drum 18… Automatic document feeder 19… Document table 20… Reading optical system 20a… Light source 20b… Mirror unit 20c… Lens unit 21 CCD element 22 Writing optical system 22a Polygon mirror 22b Mirror unit 23, 24, 25, 26 Developing units 27, 28, 29, 30 Primary charging units 31, 32, 33, 34 Cleaner 35, 36, 37, 38 ... transfer charger 39 ... fixing roller pair 40 ... transport roller pair 41 ... discharge roller pair 50 ... post-processing device lock 51 ... post-processing device lock receiver 52 ... transport guide 53 ... sort bin 54 ... discharge roller 55… Post-processing device paper discharge tray 56… Switching flapper 57… Paper discharge tray transport guide 58… Paper discharge tray roller pair 59… Sheet cooling fan 59a… Ventilation outlet 60… Paper discharge unit cover 60a… Air intake 60b… Outlet 61 ... cooling fan duct 62 ... air supply port

Claims (5)

[Claims] 1. A sheet post-processing device for discharging a sheet on which an image is formed by an image forming apparatus main body, wherein a ventilation means for applying air from a blowing means provided on the image forming apparatus main body to a sheet to be conveyed. A sheet post-processing apparatus comprising: 2. The sheet post-processing apparatus according to claim 1, wherein a tension is applied to the sheet to which the air is applied. 3. The sheet post-processing apparatus according to claim 1, wherein the sheet post-processing apparatus is configured to be detachable from the image forming apparatus main body. 4. A sheet post-processing device can be mounted,
An image forming apparatus for forming an image on a conveyed sheet, comprising: a mounting unit for mounting the sheet post-processing device according to claim 1; and a ventilation unit of the post-processing device. And an air blowing means for sending air to a sheet conveyed through the image forming apparatus. 5. The image forming apparatus according to claim 4, wherein said blowing means is capable of blowing air to both sides of the discharged sheet.