JP3479429B2 - Paper feeder - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper feeding device applied to a copying machine, a facsimile, a printer, a printing machine, and the like, and more particularly to a paper loaded on a paper tray detachable from the main body of an image forming apparatus. The present invention relates to a sheet feeding device that feeds a sheet by a pick-up roller that can be brought into and out of contact with each other, and separates a sheet feeding roller and a separation roller one by one by a separating means that can come into and out of separation.

[0002]

2. Description of the Related Art In a paper feeding apparatus having a structure in which a paper loaded on a paper tray is picked up by a pickup roller, and the paper is separated one by one by a separation unit including a paper feeding roller and a separation roller. When the paper is pulled out from the main body of the image forming apparatus, in order to prevent the paper from falling off the paper tray, it is essential to separate the pickup roller from the paper and the separation roller from the paper feeding roller.

In the conventional sheet feeding device, the release of the pickup roller pressure is disclosed in, for example, Japanese Patent Laid-Open No. 59-57841.
As disclosed in Japanese Laid-Open Patent Publication No. 59-69328, the solenoid is controlled by turning on / off a solenoid, and the pickup roller is configured to separate from the paper when it is not operating or when the paper tray is attached / detached.

Further, the release of the separation pressure is also disclosed in JP-A-6-183.
As disclosed in Japanese Unexamined Patent Publication No. 600, it is configured to control by turning on / off a solenoid, and the rollers of the separating portion are separated when not operating or when the paper tray is attached / detached.

[0005]

As described above, in the conventional paper feeding device, the pressurization of the pickup roller and the release of the pressurization of the separation roller are performed by turning on / off the solenoid. It was an obstacle to cost reduction.

As disclosed in Japanese Utility Model Laid-Open No. 60-122732, there is a method in which the separation pressure is released by attaching and detaching the paper tray, but it is not sufficient to release the separation pressure as described above. is there.

A first object of the present invention is to release the pickup pressure and the separation pressure in conjunction with the attachment / detachment operation of the paper tray, and to realize the downsizing and cost reduction of the apparatus with a simple structure. The purpose of the present invention is to provide a paper feeding device capable of preventing the paper from falling out of the paper tray when the paper tray is pulled out. A second object of the present invention is to provide a sheet feeding device which can realize an inexpensive device with a simpler configuration by integrally forming a rotating member and at least one of the blocking means. A third object of the present invention is to provide a sheet feeding device which has a simple structure and can realize an inexpensive device by integrating a rotating member and a pickup pressure blocking means and linking the rotating member and the separating pressure blocking means. That is. A fourth object of the present invention is to provide a paper feeding device which has a simple structure and can achieve cost reduction and reliability. A fifth object of the present invention is to make it possible to easily release the pickup pressure at a position outside the sheet conveyance range, and to prevent the sheet from being caught when the tray is pulled out, thus further improving the reliability of the apparatus. The present invention is to provide a sheet feeding device.

[0008]

SUMMARY OF THE INVENTION The first problem is that a sheet tray that is attachable to and detachable from the image forming apparatus main body, a pickup roller that feeds sheets stacked on the sheet tray, and the pickup roller that contacts the sheet. A pickup pressurizing means for pressurizing, a pickup pressure blocking means for blocking the pressure of the pickup, and a separating means composed of a paper feed roller and a separation roller for separating the fed sheets one by one,
Separation pressurizing means for pressing the separation roller against the paper feed roller, separation pressure blocking means for blocking separation pressurization, a rotating member that is rotated by attachment / detachment operation of the paper tray, and pulling out the paper tray. The first means includes an urging means for urging the rotating member when it is opened, an interlocking means for interlocking the rotating member and at least one of the pickup pressure blocking means and the separation pressure blocking means. To be done. The second problem is that a paper tray that is attachable to and detachable from the main body of the image forming apparatus, a pickup roller that feeds the paper stacked on the paper tray, a pickup pressurizing unit that presses the pickup roller against the paper, Pickup pressure blocking means for blocking the pressure applied to the pickup, separating means for separating the fed sheets one by one, and a separating means composed of a separating roller, and the separating roller for abutting contact with the feeding roller. Separation and pressurization means for pressing, separation pressure prevention means for preventing separation and pressurization, a rotating member that is rotated by an attaching / detaching operation of the paper tray, and a biasing force that biases the rotation member when the paper tray is pulled out. Means for solving the problem is provided by a second means which is provided with the rotating member and at least one of the pickup pressure blocking means and the separation pressure blocking means. The third problem is that a paper tray that is attachable to and detachable from the main body of the image forming apparatus, a pickup roller that feeds out the paper stacked on the paper tray, and a pickup pressurizing unit that presses the pickup roller against the paper. Pickup pressure blocking means for blocking the pressure applied to the pickup, separating means for separating the fed sheets one by one, and a separating means composed of a separating roller, and the separating roller for abutting contact with the feeding roller. Separation and pressurization means for pressing, separation pressure prevention means for preventing separation and pressurization, a rotating member that is rotated by an attaching / detaching operation of the paper tray, and a biasing force that biases the rotation member when the paper tray is pulled out. And a means for integrally forming the rotating member and the pickup pressure blocking means, and further providing interlocking means for interlocking the rotating member and the separation pressure blocking means. It is solved by means. The fourth problem is that a paper tray that is attachable to and detachable from the main body of the image forming apparatus, a pickup roller that feeds the paper stacked on the paper tray, a pickup pressurizing unit that presses the pickup roller against the paper, Pickup pressure blocking means for blocking the pressure applied to the pickup, separating means for separating the fed sheets one by one, and a separating means composed of a separating roller, and the separating roller for abutting contact with the feeding roller. Separation and pressurization means for pressing, separation pressure prevention means for preventing separation and pressurization, a rotating member that is rotated by an attaching / detaching operation of the paper tray, and a biasing force that biases the rotation member when the paper tray is pulled out. Means, the rotating member and the separating pressure blocking means are integrally formed, and the separating pressure blocking means abuts a shaft for driving the separating roller, and the material thereof is oil-impregnated polyacetate. Is solved by the fourth means is Lumpur.
The fifth object is to provide a support member for supporting the pickup roller according to any one of the first to fourth means,
This is solved by a fifth means in which a paper guide member for guiding the paper is integrally formed, and the pickup pressure blocking means abuts on the paper guide member and moves up and down the paper guide member.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view showing a sheet feeding unit which is a main part of a sheet feeding apparatus according to a first embodiment of the present invention, FIG. 2 is a sectional view taken along the line BB of FIG. 1, and FIG. 5 is a perspective view showing a gear engagement mechanism and a pressure releasing mechanism of the pickup roller, the feed roller, the separate roller of the sheet feeding unit of FIG. 4, FIG. 4 is a perspective view of the separate roller portion (a perspective view of the separation pressure releasing mechanism), and FIG. 7 is a perspective view of the separation pressure and pickup pressure releasing mechanism, FIG. 6 is a plan view of the separation pressure releasing mechanism, and FIG.
6 is a side view of the separation pressure releasing mechanism shown in FIG. 6, and FIG. 8 is a side view of the pickup pressure releasing mechanism. FIG. 8A shows a state when the pickup pressure is released, and FIG.

The sheet feeding unit A shown in FIG. 1 is a main part of the entire sheet feeding apparatus including the sheet tray 8 shown in FIG. A box-shaped housing 1 is provided with a pickup roller 2, a feed roller 3, and a separate roller 4.

The pickup arm 5 is a feed roller 3
Is supported by the shaft 3a (see FIGS. 2 and 3) of the shaft 3a.
The pickup roller 2 can be moved between the position shown by the solid line and the position shown by the phantom line in FIG.

A hook portion 5a (see FIG. 3) is provided above the pickup arm 5, and the pickup pressing spring 5b (see FIG. 3) urges the pickup arm 5 to the imaginary line position in FIG. There is. Pickup roller 2
Is driven from the feed roller 3 via the gear 7 (see FIGS. 2 and 3).

On the other hand, the separate roller 4 has a shaft 4a (see FIG.
(See bearing 4 of FIG. 4) provided at the end of the shaft 4a.
It is supported swingably in the vertical direction with the (d portion) as a fulcrum. The shaft 4 a is connected to a shaft 4 b provided in parallel with the shaft 4 a by a gear, and transmits the drive input from the gear protruding outside the paper feed unit A to the separate roller 4.

A guide plate 6 for guiding the sheet from the pickup roller 2 to the feed roller 3 is integrally formed on the pickup arm 5, and a taper surface 6a (see FIG. 3) is provided at the end thereof.

A release lever 12 which is a rotating member is provided below the tapered surface 6a. As shown in FIG. 5, the release lever 12 is a lever having a "F" shape, and has a rotation shaft 12a at the center thereof and is rotatably supported. The release lever 12 has a pin 12b facing downward, a protrusion 12d and a protrusion 12f at the other end, and the protrusion 12d has a tapered surface 12e facing the tapered surface 6a of the guide plate 6. .

A link 14 is provided on the lower back side of the release lever 12, and the link 14 has an elongated hole 14a at one end for fitting with the pin 12b, as shown in FIGS. A guide groove 14b that fits with a guide pin 17 (see FIGS. 5 and 6) fixed to the housing 1 is provided, and is configured to be movable in the left-right direction of FIGS. 6 and 7 along the groove 14b. ing.

Further, it has a hook portion 14c (see FIGS. 5 to 7) and is constantly urged by a release spring 13 in the right direction in FIGS. 6 and 7, whereby the release lever 12 is released.
Is also urged in the counterclockwise direction (the position of the virtual line in FIG. 6). A key portion 14d (see FIGS. 5 to 7) is provided downward at an end portion on the side opposite to the elongated hole 14a and faces an arm portion 15c of a pressure lever 15 described later.

As shown in FIGS. 4 to 7, an "L" -shaped pressure lever 15 is provided below the shaft 4a of the separate roller 4 so as to be rotatable about a rotary shaft 15a, and the shaft 4a is provided. The upper bearing 4c is supported by the end support portion 15b. The other end has a horizontally configured arm portion 15c, which faces the key portion 14d of the link 14 described above. Further, it has a hook portion 15d, and by being pulled by the pressure spring 16, it is urged to push up the bearing 4c.

A paper feeding operation in the paper feeding device of the first embodiment will be described.

The pick-up roller 2 is at the position shown in FIG. 2 (phantom line in FIG. 1) when the paper is fed, and comes into contact with the uppermost paper of the paper 9 stacked in the paper tray 8 by the urging force of the spring 5b. ing. When the shaft 3a of the feed roller is rotated counterclockwise by a drive source (not shown), the pickup roller 2 is also rotated counterclockwise via the gear 7 in the same manner as the feed roller 3, and the paper is directed toward the feed roller 3. Send out.

The sheet reaching the feed roller 3 is sandwiched between the feed roller 3 and the separate roller 4, and is advanced to the right in FIG. 2 by the feed roller 3 rotating counterclockwise. At this time, the separate roller 4 is driven by the drive sources (not shown) by the shafts 4a and 4b (see FIG. 4) and the gears provided on them, and is rotated counterclockwise. The separate roller 4 has a built-in torque limiter, and when two or more sheets are stacked, the lower sheet is pushed back to the left in FIG. 2 so that only the uppermost sheet is fed. .

Next, the operations of pressurizing and releasing the pickup pressure and the separation pressure according to the present embodiment will be described.

3 to 7 and 8B show a state in which the paper tray 8 is set, and the release lever 12 is
Against the biasing force received from the release spring 13, the convex portion 1
2f is pressed against the paper tray 8.

At this time, as shown in FIG. 8B, the taper surface 12e of the release lever 12 is the taper surface 6a of the guide plate 6.
The pickup arm 5 is biased by a pickup pressure spring 5b so as to press the pickup roller 2 against the sheet and press the sheet.

The link 14 is moved to the left in FIGS. 6 and 7 by the pin 12b provided at the end of the release lever 12. Therefore, the key portion 14d is the pressing lever 15
Since it is separated from the arm portion 15c of the pressure lever 15, the pressure lever 15 biased clockwise by the pressure spring 16 in FIG.
Is pushed up to bring the separate roller 4 into contact with the feed roller 3. The pickup pressure and the separation pressure are both applied, and the sheet can be fed.

When the paper tray 8 is pulled out when the paper is replenished, the paper tray 8 is separated from the convex portion 12f of the release lever 12, so that the release lever 12 is moved by the urging force of the release spring 13 to the position of the phantom line in FIG. Move to.

At this time, as shown in FIG. 8A, the tapered surface 12e of the release lever 12 is the tapered surface 6 of the guide plate 6.
The guide plate 6 is pressed against a and is pushed upward. Pickup arm 5 integrated with guide plate 6
Is pushed up against the urging force of the pickup pressure spring 5b, so that the pickup roller 2 is separated from the paper. In addition, the pin 12 provided at the end of the release lever 12
The link 14 moves to the right in FIGS. 6 and 7 by b.

Therefore, the key portion 14d contacts the arm portion 15c of the pressure lever 15 and rotates the pressure lever 15 counterclockwise in FIG. 7 against the biasing force of the separation pressure spring 16.
The bearing 4c also descends as the support portion 15b descends, and the separate roller 4 separates from the feed roller 3.
As a result, both the pickup pressure and the separation pressure are released, and the paper 9 in the paper tray 8 is pulled out of the apparatus together with the tray.

Needless to say, the urging force of the release spring 13 exceeds the urging force of the pickup pressure spring 5b and the separation pressure spring 16. Further, it goes without saying that the fixing force when the paper tray 8 is set by the fixing means (not shown) exceeds the urging force for moving the lever 12 in the virtual line direction of FIG. 6 by the release spring 13. .

In the above embodiment, the rotating member (release lever 12) is described in conjunction with the separation pressure blocking means (the key portion 14d of the link 14), but the present invention is not limited to this, and the rotation is not limited to this. The member (release lever 12) may be linked with at least one of the pickup pressure blocking means and the separation pressure blocking means.

In the above-described embodiment, the paper tray 8 which can be attached to and detached from the main body of the image forming apparatus, and the pickup roller 2 which feeds out the paper stacked on the paper tray 8.
A pickup pressing means (pickup pressing spring 5b) for pressing the pickup roller 2 against the paper, a pickup pressure blocking means (tapered surface 12e) for blocking the pressurization of the pickup, and one fed-out sheet. Separation means composed of a feed roller 3 and a separate roller 4 for separating into separate parts, and a separation pressurizing means for pressing the separate roller 4 against the feed roller 3 (pressurizing lever 15, pressurizing spring 16)
A separation pressure blocking means (the key portion 14d of the link 14) for blocking the separation pressure; a release lever 12 that rotates when the paper tray 8 is attached or detached; and a release lever 12 when the paper tray 8 is pulled out. A release spring 13 for urging, a release lever 12, and an interlocking device (pin 12b, elongated hole 14a) for interlocking at least one of the pickup pressure blocking device and the separation pressure blocking device (the key portion 14d of the link 14) are provided. The paper tray 8 is released while releasing the pickup pressure and the release pressure in conjunction with the attachment / detachment operation of the paper tray 8 and realizing the downsizing and cost reduction of the device with a simple configuration.
It is possible to prevent the paper from falling off the paper tray 8 when the paper is pulled out. Further, in the above embodiment,
A paper tray 8 that is attachable to and detachable from the image forming apparatus main body, and a pickup roller 2 that feeds out the paper stacked on the paper tray 8.
A pickup pressing means (pickup pressing spring 5b) for pressing the pickup roller 2 against the paper, a pickup pressure blocking means (tapered surface 12e) for blocking the pressurization of the pickup, and one fed-out sheet. Separation means composed of a feed roller 3 and a separate roller 4 for separating into separate parts, and a separation pressurizing means for pressing the separate roller 4 against the feed roller 3 (pressurizing lever 15, pressurizing spring 16)
A separation pressure blocking means (the key portion 14d of the link 14) for blocking the separation pressure; a release lever 12 that rotates when the paper tray 8 is attached or detached; and a release lever 12 when the paper tray 8 is pulled out. A release spring 13 for biasing the release lever 12 and a pickup pressure blocking means (tapered surface 12).
e) is integrally configured and further provided with interlocking means (pin 12b, elongated hole 14a) for interlocking the release lever 12 and the separation pressure blocking means (the key portion 14d of the link 14), the release lever 12 and the pickup pressure Blocking means (tapered surface 12
Since e) is integrated and the release lever 12 and the separation pressure blocking means (the key portion 14d of the link 14) are interlocked with each other, an inexpensive device can be realized with a simple configuration.

Next, a second embodiment of the present invention will be described. 9 is a perspective view of a separate roller portion of the sheet feeding device according to the second embodiment of the present invention (a perspective view of the separation pressure releasing mechanism), and FIG. 10 is a partial plan view of the separation pressure releasing mechanism.
FIG. 11 is a sectional view taken along line CC of FIG.

In particular, only parts different from those of the first embodiment will be described. As shown in FIG. 9, the release lever 112
Has a substantially "L" shape in plan view, and is rotatable about a rotation shaft 112a near its corner. The one ends 112e and 112f of the "L" -shaped arm are denoted by reference numeral 12 in the first embodiment.
Similar to e and 12f, the other end has a cam surface 112g that extends vertically and is bent like a key. Further, there is a hook portion 112h below it, and the release lever 113 is urged counterclockwise by the release spring 113 pulled there. The pressure lever 115 is different from the first embodiment in that it has no arm portion. In operation, the method of lowering the shaft 4a of the separate roller 4 is different from that of the first embodiment. The release lever 112 is in the state of FIG. 11A when the paper tray 8 is set, and the cam surface 112g is separated from the shaft 4a, but when the tray 8 is pulled out, as shown in FIG. 11B. Abut the shaft 4a, and the cam surface 11
The shaft 4a is pushed down by the shape of 2g. As a result, the separate roller 4 is separated from the feed roller 3, and the separation pressure is released.

Even if the tray 8 is pulled out, the shaft 4
When the drive is transmitted to a, the release lever 112
Since the cam surface 112g of the above slides on the rotating shaft, it is desirable that the cam surface 112g is formed of a material having excellent slidability (for example, oil-impregnated polyacetal).

In the second embodiment as described above, the paper tray 8 which can be attached to and detached from the main body of the image forming apparatus, the pickup roller 2 for feeding the paper stacked on the paper tray 8, and the pickup roller 2 are provided. Pickup pressing means (pickup pressing spring 5b) for contacting and pressing the paper, pickup pressure blocking means (tapered surface 112e) for blocking the pressurization of the pickup, and for separating the fed paper one by one. The separating means including the feed roller 3 and the separate roller 4 and the separate roller 4 are connected to the feed roller 3
Separation pressing means (pressing lever 115, pressing spring 16) for abutting and pressing against the sheet, separation pressure blocking means (cam surface 112g) for blocking the separation and pressing, and a release which is rotated by the attachment / detachment operation of the paper tray 8. The lever 112 and the release spring 113 for urging the release lever 112 when the paper tray 8 is pulled out are provided, and the release lever 112 and the separation pressure blocking means (the cam surface 112) are provided.
g) is integrally configured, and the separation pressure prevention means (cam surface 1)
12g) contacts the shaft 4a that drives the separate roller 4, and the material thereof is oil-impregnated polyacetal. Therefore, the cost can be reduced and the reliability can be improved with a simple configuration.

Further, in each of the above-mentioned embodiments, the paper tray 8 which is attachable to and detachable from the main body of the image forming apparatus, the pickup roller 2 for feeding the paper stacked on the paper tray 8,
Pickup pressing means (pickup pressing spring 5b) for pressing the pickup roller 2 against the paper, pickup pressure blocking means (tapered surfaces 12e, 112e) for blocking the pressurization of the pickup, and one fed-out sheet Separation means composed of the feed roller 3 and the separate roller 4 for separating into separate parts, and a separation pressurizing means for pressing the separate roller 4 against the feed roller 3 (pressurizing levers 15, 115,
The pressure spring 16), the separation pressure prevention means (the key portion 14d of the link 14, the cam surface 112g) for preventing the separation pressure, and the release lever 1 which is rotated by the attachment / detachment operation of the paper tray 8.
2, 112 and release springs 13, 113 for urging the release levers 12, 112 when the paper tray 8 is pulled out. The release levers 12, 112 and the pickup pressure blocking means (tapered surface 12e, tapered surface 112e) are provided. ) Or at least one of the separation pressure blocking means (cam surface 112g) is integrated, so that an inexpensive device can be realized with a simpler configuration.
Further, in each of the above-described embodiments, the support member (pickup arm 5) that supports the pickup roller 2 and the paper guide member (guide plate 6) that guides the paper are integrally configured, and the pickup pressure blocking means ( Tapered surface 12e, 1
12e) contacts the paper guide member (guide plate 6) and moves the paper guide member (guide plate 6) up and down, so that the pickup roller support member (pickup arm 5) and the paper guide member (guide plate 6) are integrated. Configured to
The pickup pressure blocking means (tapered surface 112e) contacts the paper guide member (guide plate 6) and raises and lowers the paper guide member (guide plate 6), so that the pickup pressure can be easily released at a position outside the paper conveyance range. Since the paper guide member (guide plate 6) is also separated when the tray is pulled out, the paper is not caught, and the reliability of the apparatus can be further improved.

[0038]

According to the first aspect of the present invention, the pickup pressure and the separation pressure are released in association with the attachment / detachment operation of the paper tray, and the size and cost of the apparatus can be reduced with a simple structure. While realizing, it is possible to prevent the paper from falling out of the paper tray when pulling out the paper tray. According to the invention described in claim 2, since the rotating member and at least one of the blocking means are integrally formed, a simpler structure can be obtained.
An inexpensive device can be realized. According to the invention of claim 3, the rotating member and the pickup pressure blocking means are integrated, and the rotating member and the separation pressure blocking means are interlocked.
Similarly to the invention described above, an inexpensive device can be realized with a simple configuration. According to the invention described in claim 4, the rotating member and the separating pressure blocking means are integrated, and the separating pressure blocking means is brought into contact with the shaft for driving the separating roller, and the material thereof is the oil-impregnated polyacetal. Thus, cost reduction can be achieved and reliability can be improved. According to the invention of claim 5,
Since the pickup roller support member and the paper guide member are integrally formed, and the pickup pressure blocking means contacts the paper guide member to raise and lower the paper guide member, the pickup pressure can be easily released at a position outside the paper conveyance range. Further, since the paper guide is also separated when the tray is pulled out, the paper is not caught and the reliability of the apparatus can be further improved.

[Brief description of drawings]

FIG. 1 is a perspective view showing a sheet feeding unit which is a main part of a sheet feeding device according to a first embodiment of the present invention.

FIG. 2 is a sectional view taken along line BB in FIG.

3 is a perspective view showing a gear engagement mechanism and a pressure release mechanism of a pickup roller, a feed roller, and a separate roller of the paper feeding unit of FIG.

FIG. 4 is a perspective view of a separate roller portion (a perspective view of a separation pressure releasing mechanism).

FIG. 5 is an overall perspective view of the separation pressure and pickup pressure release mechanism.

FIG. 6 is a plan view of the separation pressure release mechanism of the same.

FIG. 7 is a side view of the separation pressure release mechanism shown in FIG.

FIG. 8 is a side view of the pickup pressure release mechanism of the same.

FIG. 9 is a perspective view of a separate roller portion of a sheet feeding device according to a second embodiment of the invention (a perspective view of a separation pressure releasing mechanism).
Is.

FIG. 10 is a partial plan view of the separation pressure release mechanism of the same.

11 is a cross-sectional view taken along line CC of FIG.

[Explanation of symbols]

2 pickup rollers 3 feed rollers 4 separate rollers 5b Pickup pressure spring 6 guide plate 8 paper trays 12,112 Release lever 12e, 112e Tapered surface 112g cam surface 13,113 Release spring 14 links 14d Key part 15,115 Pressure lever 16 Pressure spring

Claims (5)

(57) [Claims] 1. A paper tray attachable to and detachable from a main body of an image forming apparatus, a pickup roller that feeds out the paper stacked on the paper tray, a pickup pressing unit that presses the pickup roller against the paper, Pick-up pressure blocking means for blocking pressurization, separating means for separating the fed-out sheets one by one, and a separating roller composed of a feeding roller and a separating roller; Pressurizing means, separation pressure preventing means for preventing separation and pressurization, a rotating member that rotates by attachment / detachment operation of the paper tray, and urging means for urging the rotating member when the paper tray is pulled out. A sheet feeding device comprising: the rotating member; and an interlocking device that interlocks at least one of the pickup pressure blocking device and the separation pressure blocking device. 2. A paper tray attachable to and detachable from the main body of the image forming apparatus, a pickup roller for feeding the paper stacked on the paper tray, a pickup pressurizing unit for pressing the pickup roller against the paper, Pick-up pressure blocking means for blocking pressurization, separating means for separating the fed-out sheets one by one, and a separating roller composed of a feeding roller and a separating roller; Pressurizing means, separation pressure preventing means for preventing separation and pressurization, a rotating member that rotates by attachment / detachment operation of the paper tray, and urging means for urging the rotating member when the paper tray is pulled out. A sheet feeding device, comprising: the rotating member and at least one of the pickup pressure blocking unit and the separation pressure blocking unit. 3. A paper tray attachable to and detachable from the main body of the image forming apparatus, a pickup roller for feeding the paper stacked on the paper tray, a pickup pressurizing means for pressing the pickup roller against the paper, Pick-up pressure blocking means for blocking pressurization, separating means for separating the fed-out sheets one by one, and a separating roller composed of a feeding roller and a separating roller; Pressurizing means, separation pressure preventing means for preventing separation and pressurization, a rotating member that rotates by attachment / detachment operation of the paper tray, and urging means for urging the rotating member when the paper tray is pulled out. The rotary member and the pickup pressure blocking means are integrally formed, and the interlocking means for linking the rotary member and the separation pressure blocking means is provided. Paper feeder. 4. A paper tray attachable to and detachable from the main body of the image forming apparatus, a pickup roller for feeding the paper stacked on the paper tray, a pickup pressure applying means for pressing the pickup roller against the paper, Pick-up pressure blocking means for blocking pressurization, separating means for separating the fed-out sheets one by one, and a separating roller composed of a feeding roller and a separating roller; Pressurizing means, separation pressure preventing means for preventing separation and pressurization, a rotating member that rotates by attachment / detachment operation of the paper tray, and urging means for urging the rotating member when the paper tray is pulled out. The rotating member and the separating pressure blocking means are integrally formed, and the separating pressure blocking means is in contact with a shaft for driving the separating roller, and the material thereof is oil-impregnated polyacetate. A paper feeder characterized by being tar. 5. A support member for supporting the pickup roller and a paper guide member for guiding a paper sheet, according to any one of claims 1 to 4,
The sheet feeding device, wherein the pickup pressure blocking means abuts on the paper guide member and moves up and down the paper guide member.