JP2000143041A - Sheet feeding device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet feeding device capable of properly feeding even an envelope and having excellent sheet feeding performance and an image forming device. SOLUTION: An envelope paper P having a large cavity is fed in toward a resist roller 3 in a proper condition by pressing the envelope paper P so as to return a non-bonded end part on the envelope paper main body side by a pressing roller guide 9, leading the non-bonded end part toward a pressing roller by orienting the non-bonded end part so as to approach the envelope paper main body side, bringing an end part of the oriented envelope paper P into pressure-contact with the envelope paper main body side by nipping it by the pressing roller in the downstream of a roller guide properly, and removing an air layer in the envelope paper to put it in a state in which it is flat and overlapped paper.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet feeding apparatus for feeding sheets, and is applied to, for example, an image forming apparatus such as a printer or a copying machine.

[0002]

2. Description of the Related Art Conventionally, this type of image forming apparatus has an image forming section at an upper portion thereof and a sheet deck at a lower portion thereof.

In the image forming section, an image is formed in accordance with image information.
Some books (copying machines, etc.) have a reading function of reading image information of an image of a book document.

Further, there is a type in which a sheet cassette is mounted below the image forming apparatus. For example, there is a type in which the sheet cassette is constituted by a lower cassette and an upper cassette as one feeding unit.

[0005] The sheet accommodated in the cassette is fed out by a pickup roller serving as a feeding rotary member, and is supplied to a separation feeding mechanism (for example, a feed roller serving as a separating rotary member and a retard roller serving as a pressing rotary member). Are separated and fed one by one by the cooperative action of
The sheet is conveyed by a conveying roller through a predetermined guide, guided to the nip of a pair of registration rollers in contact with a certain pressure, and guided to the image forming unit at a predetermined timing (timing synchronized with the image forming operation) by the registration roller. I will

At this time, as a configuration for feeding a large number of envelope sheets, which are one of the forms of sheets to be fed, an envelope-dedicated cassette is attached to a storage section of the cassette body, and the envelopes are stacked in the image forming apparatus main body. A storage configuration is also known (see FIG. 5).

The envelope-dedicated cassette shown in FIG. 5 will be briefly described.

[0008] As shown in the figure, the cassette for envelopes is
Generally, a stacking plate 15 for stacking a plurality of envelope sheets P, a pair of width guides 13 for regulating the width direction, a rear end guide 14 for regulating the rear end, and the uppermost one of the stacked envelope sheets P Roller (pickup roller) 11 for feeding paper
And a separation unit 12.

The envelope sheet P is properly fed one by one by the envelope-dedicated cassette constructed as described above.

Normally, envelope paper is formed by bending one sheet from each end face toward the inside of the sheet, and one side of the sheet is in an unbonded state.

[0011]

However, in the case of the above-described prior art configuration, the following problems have occurred when the envelope paper is conveyed.

The problem will be described with reference to FIG.

FIG. 6 shows a schematic structure of a main part (a part for feeding a sheet toward an image forming part) of a sheet feeding apparatus provided in an image forming apparatus according to the prior art. The state of being conveyed is shown.

As shown in FIG. 1, an envelope sheet P conveyed along a sheet conveying path (feeding path) 101 is conveyed by conveying rollers 1.
02 further transports downstream.

After being stopped once by the registration roller pair 103, the skew is corrected, the sheet is fed again at the image forming timing, and an image is formed on the envelope sheet P by the image forming unit 104 (toner image is formed). Transcribed).

By the way, when the aforementioned unbonded portion of the envelope paper P is transported upward (see FIG. 3),
The end of the unbonded portion rises within the interval in the transport path, and when the envelope paper P is inserted into the pair of registration rollers 103 as it is, the air layer existing in the envelope is pressed, and one side of the unbonded portion is pressed. One side of the envelope, including the envelope, may be misaligned with the other side, which may lead to an inability to feed the paper accurately or to deform the shape of the envelope paper.

Until the envelope sheet conveyed along the sheet conveying path reaches the registration roller pair 103, if the envelope cassette is positioned in the lower direction of the registration roller pair 103, etc. 6, the envelope paper P is bent into the same bow shape as the transport path, and the air layer in the envelope is increased. Lifting of the surface including one side of the bonding with respect to the other surface is in a larger direction, and there is a possibility that the above-described displacement is further increased.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and an object of the present invention is to provide a sheet feeding performance capable of properly feeding even when feeding an envelope. It is an object of the present invention to provide a sheet feeding apparatus and an image forming apparatus which are excellent in the above.

[0019]

In order to achieve the above object, according to the present invention, a sheet fed in a sheet feeding path is temporarily stopped to correct skew, and then re-feeded at a predetermined timing. In a sheet feeding apparatus provided with a registration roller for feeding, a sheet pressure contact unit for sending a fed sheet to the registration roller while pressing the sheet is provided.

Therefore, even when the envelope is fed as a sheet, the air in the envelope is removed by the pressure contact means, and the envelope is fed to the registration roller in a flat state.

Further, in the sheet feeding apparatus provided with a registration roller for temporarily stopping the sheet fed in the sheet feeding path, correcting the skew, and re-feeding the sheet at a predetermined timing, The sheet fed to the bent portion is provided with sheet shape correcting means for correcting the shape of the sheet by forcibly bending the sheet in the direction opposite to the bending direction of the bent portion to correct the sheet shape. A sheet is fed to the registration roller later.

Therefore, even when the sheet passes through the bent portion, the sheet is fed while its shape is corrected by the sheet shape correcting means.

Further, in the sheet feeding apparatus provided with a registration roller for temporarily stopping the sheet fed in the sheet feeding path, correcting the skew, and re-feeding the sheet at a predetermined timing, Sheet shape correcting means for correcting the shape of the sheet by forcibly bending the sheet fed to the bent portion in the direction opposite to the bending direction of the bent portion, and the sheet shape correcting means A sheet pressing means for feeding the corrected sheet to the registration roller while further pressing the sheet.

Further, a sheet storage unit for stacking and storing a plurality of sheets, a feeding unit for separating and feeding the sheets stored in the sheet storage unit one by one, and a sheet fed by the feeding unit. After being fed and having a sheet feeding path having a bent portion, and provided at a downstream side of the bent portion of the sheet feeding path, after temporarily stopping the fed sheet and correcting the skew thereof, A registration roller that re-feeds the sheet at a predetermined timing, and feeds the fed sheet to the registration roller while pressing the fed sheet downstream of the bent portion of the sheet feeding path. A sheet pressing means is provided.

A sheet shape correcting means for correcting the shape of the sheet by forcibly bending the sheet fed to the bent portion of the sheet feeding path in a direction opposite to the bending direction of the bent portion is provided. Good.

It is preferable to provide a guide member for guiding the sheet toward the sheet pressing portion of the sheet pressing means.

In the image forming apparatus of the present invention,
An image forming means for forming an image on a sheet fed by the sheet feeding device is provided.

[0028]

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, the dimensions of the components described in this embodiment,
The material, shape, relative arrangement, and the like are not intended to limit the scope of the present invention only to them unless otherwise specified.

Although the sheet feeding apparatus of the present invention is applied to an image forming apparatus such as a copying machine or a printer, the configuration and the like of the entire image forming apparatus are well-known. Omitted.

(First Embodiment) A sheet feeding device applied to an image forming apparatus according to a first embodiment of the present invention will be described with reference to FIGS.

FIG. 1 is a schematic perspective view of a main part of a sheet feeding apparatus according to a first embodiment of the present invention, and shows a state where an envelope sheet P is being fed.

FIG. 2 is a schematic sectional view of FIG. 1, and FIG. 3 is a schematic structural perspective view showing a state of envelope paper to be fed.

In the configuration for starting the feeding of the envelope paper P, for example, the envelope paper P loaded and stored in the above-described envelope dedicated cassette (sheet storage section) shown in FIG. 1)
Since a known technique such as a configuration for feeding the sheets one by one may be used, the description thereof is omitted.

Reference numeral 1 denotes a photosensitive drum for carrying a latent image or a development obtained by developing the latent image, 2 denotes a transfer roller for transferring the development formed on the photosensitive drum 1 onto a sheet, 6 Reference numeral denotes a developing device for developing a latent image formed on the photosensitive drum 1.

The photosensitive drum 1, the transfer roller 2 and the developing device 6 are main components of the image forming means.

Reference numeral 3 designates a predetermined timing, specifically, the development formed on the photosensitive drum 1 at an appropriate position after the sheet fed in the sheet feeding path is temporarily stopped to correct the skew. This is a registration roller for feeding the sheet again to the image forming unit (transfer unit) at the timing for transferring the sheet to the sheet.

Reference numeral 4 denotes an envelope paper pressing roller as a sheet pressing means which is a feature of the embodiment of the present invention. Reference numeral 9 denotes a guide for appropriately guiding the sheet (especially, the envelope paper P) toward the envelope paper pressing roller. It is a pressing roller guide plate as a member.

Reference numeral 5 denotes a paper feed roller for feeding the sheet downstream, reference numeral 7 denotes a pair of feeding (conveyance) guides for forming a sheet feeding path, and reference numeral 8 denotes a sheet after image formation. Is a transport unit for transporting further downstream.

In the above configuration, when the copy start button of the copier is pressed and an envelope is selected as the paper to be fed, the envelope paper P is conveyed from the envelope cassette to the feed guide pair 7 side. You.

The fed envelope sheet P passes between the feed guide pair 7 and moves further downstream by the feed roller 5.

At this time, the unsealed portion S1 of the envelope sheet P is separated from the envelope sheet main body S2 by the envelope sheet P being deformed into an arc shape by the curvature of the feeding guide 7, and the gap Sa is formed.
Is large.

That is, FIG. 3 shows a perspective view of an envelope sheet passing through the feeding guide 7, and FIG. 3A shows a state of the envelope sheet P in a normal horizontal state. It shows a state in which the sheet is conveyed in a state where the sheet has an end portion S1 and the unbonded end portion S1 side faces upward.

Since the unbonded end portion S1 and the envelope paper main body S2 are not bonded, a gap Sa is easily generated.

When the envelope sheet P passes through an arc-shaped portion (bent portion) of the sheet feeding path formed by the feeding guide 7, as shown in FIG. Since both the unbonded portions S1 are curved, the unbonded portions S1
The gap Sa between the sheet and the envelope sheet main body S2 is larger than usual.

Therefore, if the paper is fed toward the registration roller 3 as it is, as described above, the envelope paper P
There is an adverse effect such that the direction of the image is shifted.

Therefore, in the present embodiment, the pressing roller 4
The provision of the pressure roller guide 9 prevents such an adverse effect.

The details will be described below.

The non-adhered end S1 of the envelope paper P having the large gap Sa is moved by the pressing roller guide 9 to the envelope paper main body S.
2 and is guided toward the pressing roller 4 while orienting the non-adhesive end S1 so that the non-adhesive end S1 approaches the envelope paper main body S2.

Then, the end portion of the oriented envelope paper P is properly held by the pressing roller 4 located downstream of the roller guide, so that the edge portion is pressed against the envelope paper main body S2 and the air layer in the envelope paper is pressed. Is removed to bring the envelope paper into a flat, superimposed paper state.

Therefore, the envelope paper P in such a state is maintained at the next position of the registration roller 3 at an appropriate position.

Thereafter, the timing is adjusted by the registration roller 3 in order to synchronize with the image, and then the image is sent out from the registration roller 3 by an appropriate feed amount, and a process such as image transfer, conveyance, and fixing from the developing drum 1 is performed. Then, copying to the envelope paper is completed.

As described above, the provision of the pressing roller 4 and the pressing roller guide 9 improves the feeding performance of the envelope sheet P, and also contributes to the improvement of the image quality formed on the envelope sheet P. become.

(Second Embodiment) FIG. 4 shows a second embodiment of the present invention. In the present embodiment,
This figure shows a configuration provided with a sheet shape correcting means for correcting the shape of a sheet (especially, envelope paper) when passing through a bent feeding path.

Other configurations and operations are the same as those of the first embodiment, so that the same components are denoted by the same reference numerals and description thereof will be omitted.

FIG. 4 is a schematic sectional view of a main part of a sheet feeding apparatus according to a second embodiment of the present invention.

When the envelope sheet P passes through the feeding path formed by the feeding guide 7, there is a bent portion (bent portion) in the shape of an arc. The shape is bent in the direction.

Therefore, in the present embodiment, a curl straightening roller 10 as a sheet shape correcting means comprising a pair of small rollers and a roller is provided in the downstream portion of the bow shape in order to correct the shape of the envelope sheet P. ing.

The curl correcting roller 10 forcibly forms a curved surface on a sheet so as to have a curved surface in a direction (arrow B direction) opposite to the curved surface formed by the shape of the feeding guide 7.

As a result, the direction of the curved surface imposed by the feed guide pair 7 and the direction of the curved surface imposition by the curl correction roller 10 are offset, and the envelope paper P is in a horizontal state when the registration rollers enter, so that the paper feed before image transfer is performed. Done properly.

In particular, after the shape of the envelope paper P is corrected by the curl correction roller 10 as described above, the paper is pressed against the pressing roller 4 and the pressing roller guide 9 described in the first embodiment, and the envelope paper P is pressed. By removing the air layer inside, the feeding performance is further improved.

[0061]

As described above, according to the present invention, even when the envelope is fed, the air in the envelope is eliminated by providing the sheet pressure contact means, and the registration roller is kept flat. , The paper is properly fed, and the feeding performance is improved.

Even when a sheet (especially an envelope) passes through a bent portion, the sheet is fed while its shape is corrected by the sheet shape correcting means, so that the feeding performance is improved.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view of a main part of a sheet feeding apparatus according to a first embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view of the configuration in FIG.

FIG. 3 is a schematic perspective view showing the configuration of a fed envelope sheet.

FIG. 4 is a schematic cross-sectional view of a main part of a sheet feeding device according to a second embodiment of the present invention.

FIG. 5 is a schematic perspective view of the configuration of an envelope-dedicated cassette.

FIG. 6 is a schematic cross-sectional view of the main components of a sheet feeding device provided in an image forming apparatus according to the related art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photosensitive drum 2 Transfer roller 3 Registration roller 4 Press roller 5 Paper feed roller 6 Developing device 7 Feeding guide pair 8 Conveying part 9 Press roller guide 10 Curl straightening roller

Claims (7)

[Claims] 1. A sheet feeding apparatus comprising a registration roller for temporarily stopping a sheet fed in a sheet feeding path, correcting the skew, and re-feeding the sheet at a predetermined timing. A sheet feeding device comprising sheet pressing means for feeding a sheet to the registration roller while pressing the sheet. 2. A sheet feeding apparatus comprising a registration roller for temporarily stopping a sheet fed in a sheet feeding path, correcting the skew, and re-feeding the sheet at a predetermined timing. The sheet fed to the bent portion is provided with sheet shape correcting means for correcting the shape of the sheet by forcibly bending the sheet in the direction opposite to the bending direction of the bent portion to correct the sheet shape. A sheet feeding device for feeding a sheet to the registration roller later. 3. A sheet feeding apparatus comprising a registration roller for temporarily stopping a sheet fed in a sheet feeding path, correcting skew, and re-feeding the sheet at a predetermined timing. Sheet shape correcting means for forcibly bending the sheet fed to the bent portion in the direction opposite to the bending direction of the bent portion to correct the shape of the sheet; and And a sheet pressing means for feeding the corrected sheet to the registration roller while further pressing the sheet. 4. A sheet storage section for stacking and storing a plurality of sheets, a feeding means for separating and feeding the sheets stored in the sheet storage section one by one, and a sheet fed by the feeding means. Fed, and
A sheet feeding path having a bent portion, and a sheet feeding path provided downstream of the bent portion of the sheet feeding path to temporarily stop the fed sheet, correct skew, and then re-feed the sheet at a predetermined timing. And a registration roller for feeding the sheet, provided downstream of the bent portion of the sheet feeding path, and a sheet pressure contact unit that sends the fed sheet to the registration roller while pressing the fed sheet. A sheet feeding device, characterized in that: 5. A sheet shape correcting means for correcting a sheet shape by forcibly bending a sheet fed to a bent portion of the sheet feeding path in a direction opposite to a bending direction of the bent portion. The sheet feeding device according to claim 4, wherein the sheet feeding device is provided. 6. A sheet feeding apparatus according to claim 4, further comprising a guide member for guiding a sheet toward a sheet pressing portion of said sheet pressing means. 7. An image forming apparatus comprising an image forming means for forming an image on a sheet fed by the sheet feeding apparatus according to claim 1.