JP2000302249A - Paper feeder and image forming apparatus having the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure separation of sheets one by one and obtain constant throughput independently of the number of sheets. SOLUTION: A cutout extending from the upper end of an inclined side wall face 2 on a sheet carry side to the end on the sheet carry side of a sheet stacking face 5 is provided in a tray 1 and a recess 6 is provided in the side wall face 2 and the sheet stacking face 3 in opposition to the cutout. When sheets S are set, several fingers are inserted downwardly in the recess 6 to provide the correct position of the sheets S. A sheet detecting flag 109 of a sheet detecting means 111 for detecting the feed-out of the sheets S is moved together with a sheet feeding means 101 for contacting the sheets S during sheet feeding. Additionally, the tip of the sheet detecting flag 109 is put in the recess 6 during the movement and so the sheet detecting flag 109 is pressurized by the sheets S fed out by the sheet feeding means 101.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet feeder and an image forming apparatus provided with the same, and more particularly to a sheet feeder using a tray provided with a separation slope for separating sheets one by one.

[0002]

2. Description of the Related Art Some conventional image forming apparatuses include a paper feeder for feeding sheets (sheets) stacked on a paper tray to an image forming section. Some paper trays are provided with a paper tray having a separation slope inclined at 60 to 70 degrees with respect to the paper loading surface while being loaded.

In a paper feeder equipped with such a paper tray, when paper is fed, it moves in accordance with the paper stack height,
A roller in contact with the upper surface of the sheet applies a force in the conveyance direction to the sheet, and only one sheet is separated and fed by the resistance of the separation slope. It should be noted that such a so-called slope separation type paper feeder has an advantage that it can be provided at low cost because of its simple configuration.

On the other hand, an image forming apparatus provided with such a paper feeder is provided with a detecting means for detecting that the paper has been sent out of the paper tray, and based on a detection signal from the detecting means, the paper transporting means. The system drive timing is set.

[0005]

By the way, in such a conventional paper feeder and an image forming apparatus having the same, the contact between the leading edge of the paper and the inclined side wall surface increases the reliability of the separated paper feed. This is very important, and the reliability of the separated paper feed is affected by the state of the leading edge of the set paper. Therefore, particularly when setting a sheet in a packaged state, the end of the sheet is arranged and is vertical, so that the operator needs to set the sheet along the separation slope when setting the sheet.

However, when the sheet is set without special care, the transport end side of the sheet S runs on the separation slope 301 of the sheet tray 300 as shown in FIG. Then, in such a state, it is difficult to return to the correct state even if the rided portion is pressed from above, and in this case, the separation slope 30
1 degrades the separation performance.

On the other hand, in the conventional paper feeding device, a detecting means (not shown) for detecting the discharge of the paper is provided in the paper tray 300.
When the detecting means is disposed at such a position, if the number of sheets S stacked on the sheet tray 300 becomes small, the detecting means detects the sheet (rear end). After that, the interval until the next sheet is detected gradually increases, and accordingly, the throughput decreases.

Accordingly, the present invention has been made in view of such circumstances, and it is possible to reliably separate sheets (sheets) one by one and obtain a constant throughput regardless of the amount of sheets. It is an object of the present invention to provide a paper feeding device capable of performing the above-described operations and an image forming apparatus including the same.

[0009]

According to the present invention, there is provided a tray having a separation slope disposed downstream of a stacked sheet in the sheet conveying direction, and a tray provided so as to be able to move up and down in accordance with the amount of sheets stacked on the tray. Paper feeding means for abutting and feeding the sheet,
A sheet feeding device configured to separate sheets sent out by the sheet feeding unit one by one by the separation slope, wherein a cutout portion is formed along the slope of the separation slope. is there.

Further, the present invention is characterized in that the cutout portion is formed along the slope of the separation slope from the upper end of the separation slope to the loading surface for loading the sheets of the tray.

Further, the present invention is characterized in that the cutout portion is formed by providing a concave portion on the side of the separation slope opposite to the side where sheets are stacked.

Further, the present invention is characterized in that a notch is formed in the loading surface by extending the concave portion provided on the separation slope on the loading surface on which the sheets of the tray are loaded. .

[0013] Further, the present invention is characterized in that the notch is set to a size such that an end of the stacked sheets can be gripped.

Further, in the present invention, a concave portion having a size that allows the end of the sheet to be gripped is formed in the stacking surface corresponding to the end of the sheet stacked on the tray on the upstream side in the sheet conveying direction. It is characterized by the following.

Further, the present invention comprises sheet detecting means attached to the sheet feeding means and detecting sheet feeding by a sheet detecting flag which is rotated by being pressed by the sheet fed by the sheet feeding means, The flag is inserted into the notch.

Further, according to the present invention, the sheet feeding means includes a sheet feeding roller, and a sheet feeding arm for swingably supporting the sheet feeding roller at a position facing the notch. The detecting means is arranged at a position at the tip of the sheet feeding arm such that the sheet detection flag enters the notch.

Further, according to the present invention, there is provided an inclined member for detachably mounting the tray on the apparatus main body, and closing the cutout portion to form a part of the separation slope when the tray is mounted on the apparatus main body. It is characterized by having.

Further, the present invention further comprises sheet detecting means attached to the sheet feeding means and detecting sheet feeding by a sheet detecting flag which is rotated by being pressed by the sheet fed by the sheet feeding means. An opening for a flag to enter is provided in the inclined member.

According to the present invention, there is provided an image forming apparatus, comprising: the sheet feeding device according to any one of the above-mentioned inventions; and image forming means for forming an image on a sheet fed from the sheet feeding device. It is characterized by the following.

Further, as in the present invention, the tray is provided with a notch extending from the upper end of the separation slope to the end of the sheet stacking surface on the sheet conveying side, and the sheet conveying side is opposed to the notch. Provide recesses on the wall surface and sheet loading surface,
When setting a sheet on the tray, insert several fingers into the recess from above so that the sheet can be aligned in a correct state.

Further, the sheet detecting flag of the sheet detecting means for detecting the sheet feeding is moved together with the sheet feeding means which comes into contact with the sheet at the time of sheet feeding. further,
At the time of this movement, the leading end of the sheet detection flag is inserted into the recess, and the sheet detection flag is pressed by the sheet sent out by the sheet feeding means.

[0022]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing a configuration of an image forming apparatus provided with a paper feeding device according to a first embodiment of the present invention, and FIG. 2 is a diagram showing a configuration of the paper feeding device.

In FIGS. 1 and 2, reference numeral 1 denotes a sheet tray which stores sheets S such as A4 and A3 and is mounted on an image forming apparatus main body (hereinafter, referred to as an apparatus main body) 50. The side wall surface 2 on the sheet conveying side that is inclined at an angle of 60 to 70 degrees with respect to the sheet stacking surface 5, and the inclined side wall surface 2 (hereinafter, referred to as a separation slope) is inclined in parallel with the sheet. And a rear end regulating plate 3 that regulates the rear end of S. The sheet S is stacked on the sheet stacking surface such that the front end and the rear end are along the separation slope 2 and the rear end regulating plate 3.

Reference numeral 101 denotes a paper feed roller serving as paper feed means, and the paper feed roller 101 includes pulleys 102 and 103.
The drive of the apparatus main body side is transmitted by a belt 106 suspended by the belt, and rotates in the direction of the arrow. Also,
Reference numeral 104 denotes a paper feed arm rotatably supported by the apparatus main body 50 with a rotation shaft 105 as a fulcrum. A paper feed roller 101 is rotatably supported at a rotation end of the paper feed arm 104.

The paper feeding roller 101 provided at the rotating end of the paper feeding arm 104 as described above, when feeding paper, has its own weight of the paper feeding arm 104 and the paper feeding roller 101 or a rotation (not shown). By means of this means, the sheet S rotates downward and comes into contact with the upper surface of the sheet S.

On the other hand, in FIG.
The retard separation mechanism 20 includes a feed roller 20a and a retard roller 20b. The paper S separated one by one by the retard separation mechanism 20 passes through a transport roller 21 and is transported to an image forming unit 23 by a registration roller 22.

The image forming section 23 has a photosensitive drum 23a and a charging unit, a developing unit, a cleaning unit, and the like (not shown) disposed around the photosensitive drum 23a. By the photosensitive drum 23
After uniformly charging the surface of a, a latent image is formed by selective exposure with a laser scanner 24, and the latent image is developed into a visible image by developing with a developing unit.

The toner image visualized in the image forming section 23 is transferred to the image forming section 23 by the transfer roller 25 to which the transfer bias voltage is applied, as described above. After passing through the sheet fixing means 26, heat and pressure are applied to the sheet S
It is settled on top. Then, the sheet S on which the toner image is fixed as described above is discharged to the discharge rollers 27 and 28.
Accordingly, the sheet is conveyed along the guide path 29 and is discharged to the discharge section 30 in a face-down state.

The sheet tray 1 has cutouts 2a, 5a extending from the upper end of the center of the separation slope 2 to the center of the front end of the sheet stacking surface 5, as shown in FIGS.
a, and a first concave portion 6 is provided on the separation slope 2 and the sheet loading surface 5 so as to face the notches 2a and 5a. The notches 2a, 5a
Has a width of at least an exponent.

Here, by forming such a first concave portion 6, when setting the sheet S, several fingers F are inserted into the first concave portion 6 from above as shown in FIG. By pushing S in the direction of the rear end regulating plate 3, the front ends can be correctly aligned and aligned. And the paper S
By setting with the tip aligned correctly,
That is, the sheet S can be surely separated one by one by contacting the sheet with the separation slope 2 without turning over the leading end.

A second concave portion 8 for inserting a finger from above is formed at the rear end of the sheet stacking surface 5 as shown in FIGS. Then, place the sheet S in the sheet tray 1
When the paper S is taken out, the finger of one hand is inserted into the first recess 6 to grasp the leading end of the sheet S, and the finger of the other hand is inserted into the second recess 8 to grasp the rear end of the sheet S. The paper S can be taken out in a well-balanced manner.

On the other hand, in FIG. 2, reference numeral 111 denotes a photo interrupter provided on the side of the sheet feeding arm 104;
Is a paper sensor flag that is a sheet detection flag that constitutes a detecting unit together with the photo interrupter 111. The paper sensor flag 109 is integrated with the paper feed roller 101, and in this embodiment, is attached to the rotation shaft 110 of the paper feed roller 101. It is rotatably supported.

Here, the paper sensor flag 109 is a shield member 1 for blocking the optical axis (not shown) of the photo interrupter 111.
09a is provided integrally with the sheet feeding roller 101.
When the sheet S is pressed by the paper S rising along the separation inclined surface 2 by the rotation of the shutter 110 and rotates counterclockwise to a position shown by a two-dot chain line with the rotation shaft 110 as a fulcrum,
The optical axis of the photo interrupter 111 is blocked by a.

When the paper S is sent out by the paper feed roller 101 and the pressing by the paper S is released, the paper S is rotated clockwise by its own weight or the urging means, and returns to the position shown by the solid line. The optical axis of the photo interrupter 111 is open. The paper feeding arm 104 is provided with a stopper (not shown), and the paper sensor flag 109 is held at a position shown by a solid line.

Then, when the optical axis is opened after the optical axis is blocked by the shielding member 109a, the photo interrupter 111 notifies the control means (not shown) that the rear end of the sheet S has passed. The control means drives the retard separation mechanism 20, the registration roller, and the like based on the detection signal.

In the present embodiment, the paper sensor flag 109 is provided at a position facing the first recess 6, and when held by the stopper, the leading end of the paper sensor flag 109 is positioned as shown in FIG. As shown, the first recess 6
Into the feed roller 1
The paper S rising along the separation slope 2 by the rotation of 01 can be reliably detected.

When the paper is fed, the paper sensor flag 109 is moved together with the paper feed roller 101 as described above.
At the time of movement, the leading end of the paper sensor flag 109 is
By allowing the paper S to enter, the paper S can be reliably detected, and a constant throughput can be obtained regardless of the amount of the paper S.

Next, a second embodiment of the present invention will be described.

FIG. 6 is a perspective view of the paper feeding apparatus according to the present embodiment, in which 200 is a paper tray.
The paper tray 200 has a notch 202 having a width corresponding to the width of a hand extending from the upper end of the separation slope 201 to the leading end of the paper loading surface 201a.

Reference numeral 203 denotes a slope plate which is provided in the apparatus main body (not shown) and is a slope member which closes the cutout portion 202 and forms a part of the separation slope 201 when the paper tray 200 is mounted on the apparatus main body. The slope plate 203 is provided with an opening 204 into which the tip of the paper sensor flag 205 enters. Note that, in the figure, reference numeral 206 denotes a paper feed roller, and 207 denotes a paper feed arm.

Then, with this configuration,
When setting the sheet S on the sheet tray 200, the notch 202 can be used to set the sheet S in a correct state, so that operability is good. Also, the paper tray 200
When the is attached to the apparatus main body, a part of the separation slope 201 is formed by the slope plate 203 that covers the notch 202,
Separated sheet feeding using a slope can be realized.

Further, as in this embodiment, the slope plate 2
When the sheet tray 200 is formed separately from the sheet tray 200, for example, the sheet tray 200 is formed of plastic, and the slope plate 203 is formed of metal.

[0044]

As described above, according to the present invention, when a sheet is set on a tray, a finger is inserted from above into a notch provided on a separation slope on the sheet conveying side of the tray so that the sheet is correctly positioned. Can be aligned to
At the time of sheet feeding, sheets can be reliably separated one by one, and sheet feeding performance can be stabilized.

Further, by moving the sheet detection flag of the sheet detecting means for detecting sheet feeding together with the sheet feeding means at the time of sheet feeding, a constant throughput can be obtained regardless of the amount of sheets. Further, when the sheet detection flag moves, the sheet can be reliably detected by inserting the leading end into the recess.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration of an image forming apparatus including a sheet feeding device according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of the paper feeding device.

FIG. 3 is a perspective view of a front end of a paper tray of the paper feeding device.

FIG. 4 is a top view of the paper feeding device.

FIG. 5 is a diagram illustrating an operation of setting a sheet on the sheet tray.

FIG. 6 is a perspective view illustrating a configuration of a sheet feeding device according to a second embodiment of the present invention.

FIG. 7 is a diagram illustrating a state where sheets are set on a sheet tray of a conventional sheet feeding device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Paper tray (tray) 2 Separation slope 2a Notch 3 Rear-end regulating plate 5 Paper loading surface (sheet loading surface) 5a Notch 6 First recess 8 Second recess 101 Feed roller 109 Paper sensor flag 111 Photo interrupter 200 Paper tray (tray) 201 Separation slope 201a Paper loading surface (sheet loading surface) 202 Notch portion 203 Slope plate F Finger S Paper (sheet)

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Seiji Inada 3-30-2 Shimomaruko, Ota-ku, Tokyo F-term in Canon Inc. (reference) 3F343 FA02 FB01 GA02 GB01 GC01 GD01 HA12 HA33 HB01 HC24 HC28 HC30 JA01 KB03 KB18 LC02 MA03 MA09 MA23

Claims (11)

[Claims] 1. A tray having a separation slope disposed downstream of a sheet to be stacked in a sheet conveying direction, and a sheet feeder provided so as to be able to move up and down in accordance with the amount of the sheet stacked on the tray, and to contact and feed the sheet. Means, wherein the sheet fed by the sheet feeding means is separated one by one by the separation slope, wherein a notch is formed along the slope of the separation slope. Paper feeder. 2. The sheet feeding device according to claim 1, wherein the cutout portion is formed along a slope of the separation slope from an upper end of the separation slope to a loading surface on which sheets of the tray are loaded. apparatus. 3. The sheet feeding device according to claim 1, wherein the cutout portion is formed by providing a concave portion on the side of the separation slope opposite to a side on which sheets are stacked. . 4. The feeding device according to claim 3, wherein a notch is formed in the stacking surface by extending the recess provided in the separation slope on the stacking surface on which the sheets of the tray are stacked. Paper equipment. 5. The sheet processing apparatus according to claim 1, wherein the notch has a size such that an end of the stacked sheets can be gripped. A paper feeder according to claim 1. 6. A concave portion having a size such that an end of a sheet can be gripped on the stacking surface corresponding to an end of the sheet stacked on the tray on an upstream side in a sheet conveying direction. The sheet feeding device according to claim 5, wherein 7. A sheet detecting means attached to the sheet feeding means and detecting sheet feeding by a sheet detecting flag which is rotated by being pressed by a sheet fed by the sheet feeding means, wherein the sheet detecting flag is 2. The sheet feeding device according to claim 1, wherein the sheet feeding device enters the notch. 8. The sheet feeding means includes a sheet feeding roller, and a sheet feeding arm for swingably supporting the sheet feeding roller at a position facing the notch, and the sheet detecting means includes a sheet feeding arm. 8. The sheet feeding device according to claim 7, wherein the sheet detecting flag is disposed at a position at the tip of the sheet feeding arm such that the sheet detection flag enters the notch. 9. An apparatus according to claim 9, wherein said tray is removably provided in said apparatus main body, and said tray is provided with an inclined member for closing said cutout portion and forming a part of said separation slope when said tray is mounted on said apparatus main body. The sheet feeding device according to claim 1, wherein 10. A sheet detecting means which is attached to the sheet feeding means and detects sheet feeding by a sheet detecting flag which is rotated by being pressed by a sheet fed by the sheet feeding means, wherein the sheet detecting flag enters. The sheet feeding device according to claim 9, wherein an opening is provided in the inclined member. 11. An image forming apparatus comprising: the sheet feeding device according to claim 1; and image forming means for forming an image on a sheet sent from the sheet feeding device. Characteristic image forming apparatus.