JPH02144340A - Sheet feeding device - Google Patents

Abstract

PURPOSE:To perform normal formation of a picture by a method wherein a separating member cover having a friction factor against a sheet lower than that between sheets is capable of being mounted to a sheet separating member, where occasion demands, and two or more sheets are fed without re-separation. CONSTITUTION:When a sheet feeding device 1 is mounted to a picture output device, a separating member cover 22 is mounted between a feed roller 20 and a separating rubber pad 21 in a state to cover the separating rubber pad 21 therewith. A friction factor between the separating member cover 22 and a sheet is set to a value lower than that between sheets. The sheet discharged through a discharge port 25 of the feed device 1 is guided between the feed roller 20 of the picture output device and the separating member cover 22. Since when the sheets are fed in a doubled state, the friction factor between the separating member cover 22 and the sheet is lower than that between the sheets, the sheets are fed in a doubles state, a picture is formed on the one and the other is discharged in a blank state. Thus, choking with a remaining sheet is not prevented from occurring to a picture forming device.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a sheet feeding device for a sheet intake device such as an image forming apparatus.

(Prior Art) Conventionally, sheet feeding in an image forming apparatus such as a copying machine is generally carried out using a paper feed cassette, but the number of continuous copies made using this paper feed cassette is limited to 250 sheets due to the capacity of the paper feed cassette. It was about. Therefore, when performing continuous copying of a large number of sheets, a large-capacity sheet feeding device as described in Japanese Patent Laid-Open No. 59-223635 has been devised in order to reduce work interruptions due to paper replenishment. .

As shown in FIG. 6, in this sheet feeding device, when a sheet feeding device 61 is attached to an image forming device 62 and sheets S are stacked and set on a paper table 63 in the sheet feeding device 61,
The paper tray 63 moves upward until the upper surface of the stacked sheets S contacts the paper feed roller 64 with a constant pressure, and then stops. Then, due to the paper feeding force generated by the rotation of the paper feed roller 64, only one sheet S on the top of the stacked papers is separated by the separation claw 65 and sent out between the guide plates 66.

Then, the sheet S sent out is taken into the main body of the image forming apparatus 62 by the conveying roller 67 and the driven roller 68.

Generally, when the sheets S are cut into a standard size, the sheets S come into close contact with each other at the cut edges, so in the conventional sheet separation method using the separating claw method described above, the sheets S are separated by loosening the sheet bundle. I needed to make it easier. Therefore, if this preliminary work is neglected, it is likely that two or more sheets S will be fed at the same time. Therefore, in recent years, in order to save the labor of the above-mentioned preparatory work, the number of devices using a frictional separation method as shown in FIG. 5 has increased. This is because a separating member 72 is provided at a position facing the feeding roller 71, and when the sheet S is fed by the feeding roller 71, the coefficient of friction between the sheets S and between the sheet S and the separating member 72 is reduced. The difference is used to separate sheets.

(Problem to be Solved by the Invention) However, the sheet feeding device 61 in FIG.
The sheet separation mechanism was designed assuming a mold separation method, and the image forming apparatus 62 was not equipped with a sheet separation mechanism. Therefore, when the sheet feeding device 61 described above is used in an image forming apparatus 62 equipped with a sheet separation mechanism using a frictional separation method, the sheet S once separated by the separating claw 65 in the sheet feeding device 61 is transferred to the image forming device 62. They will be separated again within. Therefore, if two or more sheets S are fed incorrectly during paper feeding, a reseparated residual sheet will be generated in the image forming device 62, and this residual sheet may cause sheet clogging or damage to multiple sheets S. This has resulted in the inconvenience that an image may be formed across the two sides.

The present invention has been made to solve the problems of the prior art described above, and its purpose is to prevent residual sheets from being generated even when two or more sheets are fed from the sheet feeding section. The purpose is to provide a sheet feeding device for feeding sheets.

(Means for Solving the Problem) In order to achieve the above object, the present invention includes a sheet storage section that can store a large number of sheets, and a sheet feeding section that sequentially feeds out the sheets of this sheet storage section. The fed sheets are then separated one by one by a rotatable feeding roller and a separating member having a predetermined friction coefficient provided in contact with the feeding roller using a well-equipped sheet separating mechanism to form an image. In the sheet feeding device for feeding the sheet to the above-mentioned section, a separation member cover having a coefficient of friction with respect to the sheet smaller than a coefficient of friction between the sheets can be attached to the separation member as necessary.

(Function) In the present invention having the above configuration, for example, by attaching a separation member cover having a coefficient of friction with respect to the sheet to the separation member that is smaller than a coefficient of friction between the sheets to the separation member provided in the main body of the image forming apparatus, Even if two or more sheets are fed, the frictional force between the sheets is greater, so the sheets are fed as they are without being separated again. After that, image formation is performed only on the topmost sheet of the two or more sheets fed, so the other sheets are ejected blank, but image formation does not occur normally. Therefore, it is not a big problem compared to inconveniences such as sheet clogging and images being formed across multiple sheets.

(Example) An example of the present invention will be described using FIGS. 1 to 4. A sheet feeding device 1 in this embodiment includes a first feeding section 3 that feeds sheets S from a paper feeding cassette 2, and a large number of sheets S stacked and set in a sheet storage section 5 on a sheet table 4.
A second feeding section 6 that feeds the
6 each have a sheet separation mechanism using a friction separation method. The sheet separation mechanism of the first feeding section 3 is composed of a first paper feeding roller 7 and a rubber pad 8, and when the sheet S is sent out by the rotation of the first paper feeding roller, the sheet S
The friction coefficient of the rubber pad 8 is set so that when the sheet passes between the first paper feed roller 7 and the rubber pad 8, the friction force between the sheet S and the rubber pad 8 is greater than the friction force between the sheet S and the rubber pad 8. Therefore, only the uppermost sheet S is separated and conveyed to the common feeding roller pair 9, and then conveyed to the image forming apparatus IO. The sheet separation mechanism of the second feeding section 6 is composed of a second feeding roller 11 and a pair of separation rollers 12, and one roller of the pair of separation rollers 12 conveys the sheet S to the pair of common feeding rollers 9. The other roller rotates to push back the sheet S, thereby separating the sheet S by the same action as that of the first paper feed roller 7 and the rubber pad 8, and this sheet S is separated from the common feed roller. After being conveyed to the pair of conveying rollers 9, it is conveyed to the image forming apparatus (2)0.

The image forming apparatus 10 to which the sheet feeding apparatus 1 is mounted has an image reading apparatus 14 disposed on a pedestal 13 serving as a base thereof, and an image output apparatus 1 disposed inside the pedestal 13.
5, this image reading device 14 includes a scanner means 16 for reading images, and an image output device 1.
5 and a control means (not shown) for controlling the sheet feeding device 1.
The image forming apparatus 17 has an image forming means 17 that forms an image on the sheet S fed from the sheet S, and a paper ejection means 18 that ejects the sheet on which the image is formed to a paper ejection tray. The image output device 15 is equipped with a sheet separation mechanism of a frictional separation type using a feeding roller and a separation rubber pad 21 as a separation member in the sheet take-out section 19. 15, as shown in FIG.
The friction coefficient between the separation member cover 22 and the sheet S is set to be smaller than the friction coefficient between the sheets S. Furthermore, a guide portion 23 for guiding the sheet S during sheet conveyance is formed at the end of the separation member cover 22 and extends in the upstream direction of sheet conveyance, and abuts on this guide portion 23 to guide the sheet S. A sheet guide unit 24 is disposed within the sheet take-out section 19.

The operation of the above configuration will be explained.

When an image forming operation command signal is sent from the image reading device 14, the first paper feed roller 7 or the second paper feed roller 11 arranged in the sheet feed device 1 is selected and operated, and the paper feed cassette 2 or the sheet is The sheets S on the table 4 are separated one by one and conveyed to a common feed roller pair 9. The sheet S conveyed to the common feeding roller pair 9 is discharged to the image output device 15 from the output port 25. And this sheet S
is guided by the sheet guide unit 24 disposed in the sheet take-out section 19 and the guide portion 23 of the separation member cover 22 and is conveyed between the feeding roller 2o and the separation member cover 22. This feeding roller 20 and separation member cover 2
Since there is no sheet separation effect between the sheet and the sheet, the sheet is conveyed to the pair of registration rollers 26 by the rotation of the feeding roller 2o, passing over the separating member cover 22 without being separated again. The sheet S, whose skew has been corrected by the registration roller pair 26, passes between the photoreceptor 27 and the transfer section 28, where the image is transferred, and then passes through the fixing roller 29, where the image is fixed on the sheet S. will be carried out. Further, the fixed sheet S is discharged from the pair of paper discharge rollers 30 by the paper discharge means 18 through the discharge path 31 onto the paper discharge tray 32 .

Further, the sheet feeding device 1 is equipped with a cart 33 at the bottom, and can be freely attached to and detached from the image output device 15. Therefore, when large-capacity sheet feeding is not required, the above-mentioned truck 33 is installed at the sheet take-out section of the image output device. By removing the separation member cover 22, the sheet guide unit 24, and the sheet feeding device 1, and installing the paper feeding cassette 2 in their place, the structure becomes the same as that of the conventional image forming apparatus 1O shown in FIG.

In the above embodiment, the sheet guide unit 24 has the role of guiding the sheet S discharged from the discharge port 25 of the sheet feeding device 1 between the feeding roller 20 of the image output device 15 and the separating member cover 22. However, this may be formed integrally with the discharge port 25 of the sheet feeding device 1, or furthermore, the separation member cover 22 and the sheet guide unit 24 may be formed integrally. .

Further, in the above embodiment, the selection of the feeding sheet on the sheet feeding cassette 2 or the sheet table 4 is performed by the image reading device 14, but a selection means may be provided on the sheet feeding device 1 side. do not have. Further, the number of feeding sections of the sheet feeding device l may be one or three or more, and can be set arbitrarily, and the sheet separation mechanism may take out sheets one by one and send them to the image forming device. Any configuration is acceptable as long as it can do so.

(Effect of the invention) By providing a separating member cover that suppresses re-separation of sheets in the image forming apparatus main body, there is no re-separation of sheets even when two or more sheets are fed, and the image forming apparatus Since no residual sheet is generated at the sheet take-out section, when sheets are continuously fed, problems such as sheet clogging due to the residual sheet or formation of an image across a plurality of sheets do not occur.

Furthermore, since the sheet feeding device can be installed without changing the specifications of the image forming apparatus main body, the image forming apparatus can also be installed in an image forming apparatus for which installation of a sheet feeding device was not considered at the time of design.

Furthermore, by providing a plurality of feeding sections in a sheet feeding device, an image forming apparatus that is equipped with only one cassette feeding section can be equipped with a plurality of feeding sections.

[Brief explanation of the drawing]

Fig. 1 is a schematic sectional view showing an embodiment of the present invention, Fig. 2 is a sectional view showing the main parts of this embodiment, Fig. 3 is an enlarged sectional view of Fig. 2, and Fig. 4 is a sectional view showing this embodiment. 5 is a schematic sectional view showing a conventional example, and FIG. 6 is a schematic sectional view showing another conventional example. Explanation of symbols 1...Sheet feeding device 2...Paper feeding cassette 3...
・First feeding section 4...Sheet stand 5...Sheet storage section 6...Second feeding section 7...First paper feeding roller
8...Rubber pad 9...Common feed roller pair 0...Image forming device +1...Second paper feed roller 2
...Separation roller pair 13...Pedestal 4...
Image reading device 15... Image output device 6... Scanner means 17... Image forming means 8... Paper ejection means 19... Sheet take-out section 20... Feeding roller 21... Separation rubber pad 22... Separation member cover 23... Guide section 24... Sheet guide unit 25... Discharge port 26... Registration roller pair 27... Photoreceptor 28... Transfer section 29.
... Fixing roller 30 ... Paper ejection roller pair 31 ...
- Paper discharge path 32... Paper discharge tray 33... Cart Figure 1

Claims (4)

[Claims] (1) Equipped with a sheet storage section that can store a large number of sheets, and a sheet feeding section that sequentially feeds out the sheets in this sheet storage section, and a rotatable feeding roller and a rotatable feeding roller that feeds the fed sheets one after another. In a sheet feeding device that separates sheets one by one and sends them to an image forming section by a sheet separating mechanism equipped with a separating member having a predetermined friction coefficient provided in contact with the sheets, the separating member has a friction coefficient between the sheets that is A sheet feeding device characterized in that a separation member cover having a coefficient of friction smaller than that of can be attached as necessary. (2) The sheet feeding device according to claim 1, wherein the sheet storage section and the sheet feeding section of the sheet feeding device are separable from the sheet separation mechanism. (3) The sheet feeding device according to claim 1 or 2, characterized in that a plurality of sheet storage sections are provided. (4) The sheet feeding device according to any one of claims 1 to 3, wherein the separation member cover is provided with a guide portion extending from an end thereof in an upstream direction of sheet conveyance.