JP2003246467A - Sheet feeder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sheet feeder capable of smoothly feeding both an upward curled sheet material and a downward curled sheet material without causing damage such as buckling. <P>SOLUTION: A sheet conveying device has a swingable intermediate plate for supporting the front edge of the sheet material from the back face side and energizing it toward a feed roller, between a paper feeding tray inclined downward to the front, and the feed roller, and feeds the sheet material with the front edge clamped between the intermediate plate and the paper feeding tray, by the rotation of the feed roller. The sheet conveying device is provided with the paper feeding tray for stacking the sheet material, and a side regulating means capable of moving the sheet material in a lateral direction to a conveying direction. The sheet material guide face position of the side regulating means is different in the height position in a right-angled direction to a paper feeding direction, from the center position of the paper feeding tray for stacking the sheet material. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention feeds a sheet material from a paper feed tray which is inclined with respect to an automatic sheet feeding device mounted in a main body of an image forming apparatus such as a copying machine and an image reading apparatus. The present invention relates to a sheet conveying device.

[0002]

2. Description of the Related Art In an automatic sheet feeding apparatus mounted on an image reading apparatus such as a copying machine, a friction separating method has been proposed in which a sheet material is separated and conveyed by using a sheet feeding roller and a separating pad. As proposed in Japanese Laid-Open Patent Publication, it is adopted in many office machine products that are particularly required to be small in size and low in cost. This is to press the separation pad against the outer peripheral surface of the paper feed roller via a pressing member, and to let the sheet material pass through the nip portion between them, and to separate the friction coefficient between the paper feed roller and the sheet material. By setting the friction coefficient between the pad and the sheet material to be larger, and further setting the friction coefficient between the sheet material and the sheet material to be smaller than the friction coefficient between the separation pad and the sheet material, The sheet material is prevented from being double-fed and only one sheet is fed.

In this way, an intermediate plate for supporting the front end portion of the sheet material and pressing it against the sheet feeding roller is swingably arranged in front of the sheet feeding roller for feeding the sheet material. Further, in front of the middle plate, a paper feed tray that supports the latter half of the sheet material is mounted. The sheet separating unit that has been proposed so far has a structure in which the vicinity of the central portion of the leading edge of the sheet material is picked up by a sheet feeding roller.

As a mechanism for assisting the sheet feeding roller to feed the sheet material when the intermediate plate presses the sheet material against the sheet feeding roller, an auxiliary roller rotating in synchronization with the sheet feeding roller is arranged in front. It may be done. The automatic sheet feeding device is desired to be downsized in accordance with downsizing of a copying machine or the like, and as one means for achieving this, the paper feed tray is formed at a steep angle with respect to the main body of the device, that is, at a right angle to the horizontal plane. A method is adopted in which the device is tilted in the direction and mounted to reduce the occupied area. At this time, since the front end of the sheet material is supported by the middle plate and the rear half of the sheet material is supported by the document tray, the sheet material hits the abutting member by its own weight and stops at that position. At this time, not all the sheet materials are stacked in an orderly manner, and depending on the sheet material, the sheet material may be curled upward or downward, so that the sheet materials may not be correctly placed against the paper feed roller and the separation pad. There was a possibility that it could not be fed.

In order to avoid these problems, for example, in order to prevent an improper feeding of a document having an upper curl, the sheet is generally made to face the middle plate supporting the lower surface of the front end of the sheet material. A guide member that guides the upper surface side of the material is fixedly arranged, and the interval between the two is set to a predetermined interval so that the front end of the sheet material is lightly sandwiched and its posture is not greatly collapsed. It is preventing.

[0006]

On the other hand, the sheet material curled downward is pressed against the sheet feeding roller by the intermediate plate, and the intermediate plate serves as a guide member, and is against the sheet feeding roller and the separation pad. Since the sheet material is corrected so that it is correctly fed, the posture does not greatly change.

However, since the intermediate plate is pressed against the paper feed roller, the tangential direction in which the intermediate plate contacts the paper feed roller does not coincide with the tangential direction in which the separation pad contacts the paper feed roller. A space having a cross section of a triangle having two sides of these two tangents is formed between the paper feed roller, the intermediate plate, and the separation pad, and when the leading end of the sheet material is fed into this space, it is corrected until then. The leading edge of the sheet material is now free and is sent as it is toward the separation pad. That is,
The intermediate plate that serves as a guide and the separation pad surface are not horizontal, and the sheet material is always conveyed to the nip at an angle.

Therefore, particularly in a sheet feeding device having a steep tray angle, the plunging angle of the sheet material with respect to the separation pad becomes close to a right angle, and at this time, the front end portion of the sheet member contacting the separation pad is damaged by the impact. This causes an adverse effect such as buckling of the front end portion of the sheet material. Further, when the intermediate plate and the separation pad are stepped when conveyed from the intermediate plate to the nip, the leading edge of the sheet material is caught,
Sheet material cannot be conveyed. Feeding failure occurs without feeding.

The present invention has been made in view of the above problems, and its object is to smoothly feed an upwardly curled sheet material or a downwardly curled sheet material without being damaged by buckling or the like. An object of the present invention is to provide a sheet feeding device capable of feeding.

[0010]

In order to achieve the above object, the present invention supports a front end portion of a sheet material from a back surface side between a paper feed tray and a paper feed roller which are inclined forward and downward. A swingable middle plate that urges toward the paper feed roller is provided, and a sheet material having a front end sandwiched between the middle plate and the paper feed roller is fed by rotation of the paper feed roller. In the sheet conveying device, the sheet feeding tray on which the sheet materials are stacked and the side regulating means that can move the sheet materials in the left-right direction with respect to the conveying direction are provided at the central position of the sheet feeding tray on which the sheet materials are stacked. On the other hand, the position of the sheet guide surface of the side regulating means is different in the height position in the direction perpendicular to the feeding direction.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a state in which a sheet feeding device 1 is mounted on a main body of a copying machine or the like. The sheet feeding apparatus 1 includes a sheet feeding tray 3 protruding from a frame fixed to the apparatus main body. The paper feed tray 3 is formed of a plate-shaped member, and the mounting surface on the upper surface side on which the sheet material P is mounted is smoothly finished.

The paper feed tray 3 is attached so as to be inclined forward and downward with respect to the frame, and its mounting surface and the horizontal plane are angled. This paper tray 3
A side regulating plate 4 is provided on the mounting surface in parallel with the conveying direction F of the sheet material P, and a movable structure is adopted so as to correspond to the sheet material P of each size. The side regulating plate 4 that regulates both sides of the sheet material P is a sheet material P.
In order to transform the sheet material into a bow shape, the sheet material P has a slope on the side of the sheet conveyance direction F that is inclined upward with respect to the sheet conveyance direction F of the sheet material P. This inclined surface serves as a guide surface for the sheet material P, and guides the sheet material P to the contact surface with the leading edge while correcting the shape of the sheet material P.

A guide member 13 for guiding the upper surface of the sheet material P deformed into an arch is arranged so as to face the paper feed tray 3, and a plurality of sheet materials P are stacked.
The rampage of is suppressed. An intermediate plate 6 is provided on the lower end side of the paper feed tray 3.
Are arranged. The middle plate 6 has a gentle bent portion at the center and has an escape portion for avoiding the paper feed roller 20. One end is connected to the drive unit by a gear and is swingably supported. A compression spring having one end fixed to a frame is connected to the rear surface of the front end portion of the middle plate 6. As a result, the front end of the middle plate 6 is urged toward the sheet feeding roller 20 described later.

The paper feed roller 20 with which the intermediate plate 6 is in contact is attached to a paper feed roller shaft whose one end is connected to a drive unit by a gear. The paper feed roller 20 and the paper feed roller shaft are supported by a frame and rotatably connected by a gear. The sheet feeding roller 20 is rotationally driven by a driving device (not shown) via the sheet feeding roller shaft. The separation pad is pressed from below on the outer peripheral surface of the paper feed roller 20, and a nip portion is formed therebetween.

The separation pad is fixed to the upper surface of the arm front end portion having a swing center at the rear end, and the arm is biased upward by a compression spring interposed between the arm front end and the frame. Accordingly, the outer peripheral surface of the paper feed roller 20 is pressed with an appropriate pressure. The sheet material P fed by the rotation of the sheet feeding roller 20 passes through the nip portion, and the friction coefficient μ1 between the outer peripheral surface of the sheet feeding roller 20 and the sheet material P at this time is the separation pad and the sheet material P. Is set to be larger than the friction coefficient μ2 of
1, μ2 becomes larger than the friction coefficient μ3 between the sheet materials P. That is, between the friction coefficients μ1, μ2, μ3, μ1
>Μ2> μ3 is set. As a result, even when two or more sheet materials P enter the nip portion, only the uppermost sheet material P in contact with the outer peripheral surface of the paper feed roller 20 is correctly fed.

The sheet material P thus fed is fed while being guided by a conveyance guide formed in the vicinity of the nip portion. First, a contact surface with a sheet tip that is inclined forward and upward is formed substantially along the locus of movement of the tip edge. The contact surface with the leading edge of the sheet regulates the position of the leading edge of the sheet material P at the time of replenishment, and is formed substantially at right angles to the mounting surface of the sheet feeding tray 3 on which the sheet material P is stacked.
The intermediate plate 6 is connected to a motor (not shown), and when the motor is started, the intermediate plate 6 swings around the shaft to move to the replenishment position shown by the chain double-dashed line, and the sheet material P After replenishment, it returns to the feeding position shown by the solid line in the figure.

The operation of the sheet feeding apparatus 1 according to this embodiment is as follows.

First, the user stacks a plurality of stacked sheet materials P on the document tray, and the sheet materials P are placed along the document tray so that the sheet materials P come into contact with the abutting portions in the sheet material conveyance direction F. The sheet material P is slid between the plate 6 and the paper feed roller 20. At this time, the side regulating plate 4 partly submerged under the sheet material P is slid toward the central portion of the sheet material P, and the front end portion of the sheet material P is deformed into a bow while being guided by the side regulating plate 4.

After the operation is started, the intermediate plate 6 is swung to raise the leading end of the sheet material P along the abutting portion, and the sheet material P is arranged at the replenishment position shown by the solid line in the figure. At this time, above the sheet material P,
The posture is corrected by being regulated by the guide member 13 provided to prevent the sheet material P from being violent. At the same time, a flat portion is formed near the center of the front end of the sheet material P. The flat portion formed here is brought into contact with the outer peripheral portion of the sheet feeding roller 20 and is sandwiched between the intermediate plate 6 and the sheet feeding roller 20. At the same time, as the paper feed roller 20 rotates, the paper is fed to the nip portion between the paper feed roller 20 and the separation pad. At this time,
Only the uppermost sheet material P is separated from the other sheet materials P and fed.

As described above, before the sheet material P is fed to the nip portion, a flat portion having a waist is formed in the front portion of the sheet material P which is brought into contact with the sheet feeding roller 20 to stabilize the sheet material. It can be fed to the separation unit in a posture. As a result, harmful buckling may occur at the front end of the sheet material P, and feeding failure without feeding due to being caught in the separation pad portion can be prevented, and the sheet material P can be conveyed smoothly. Like The document tray shape is not limited to the one shown in the figure, and the shape shown in the figure is also valid. Further, the guide member for preventing the sheet material from being rough is for the purpose of forming a flat portion in front of the separating portion, and is not particularly limited in shape or position.

[0021]

As is apparent from the above description, according to the present invention, the front end portion of the sheet material is curled upward or downward by curling the front end portion of the sheet material from both sides and from above. Even if the sheet material is still in the same position, a flat portion is formed at the front end of the sheet material to stabilize the entry into the nip area and prevent harmful buckling at the front end of the sheet material during sheet feeding. It is possible to prevent the occurrence of a sheet feeding failure without feeding due to the occurrence of a catch at the separation pad portion, and it is possible to smoothly transport the sheet material.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a sheet feeding device according to the present invention.

FIG. 2 is a perspective view of a side guide of the sheet feeding device according to the present invention.

FIG. 3 is a perspective view of a side guide of the sheet feeding device according to the present invention.

FIG. 4 is a perspective view of a side guide of the sheet feeding device according to the present invention.

FIG. 5 is a sectional view of a sheet feeding device according to the present invention.

FIG. 6 is a cross-sectional view of a conventional sheet feeding device.

FIG. 7 is a cross-sectional view of a conventional sheet feeding device.

FIG. 8 is a perspective view of a conventional sheet feeding device.

FIG. 9 is a plan view of a conventional sheet feeding device.

[Explanation of symbols]

3 paper trays 4 Side guide 5 Side regulation means 6 Middle plate 13 Guide member 20 paper feed rollers P sheet material

Claims (2)

[Claims] 1. A swingable center for supporting a front end portion of a sheet material from a back side between a paper feed tray and a paper feed roller inclined downward to the front and biasing the same toward the paper feed roller. In a sheet conveying device having a plate and feeding a sheet material having a front end sandwiched between the middle plate and the sheet feeding roller by rotation of the sheet feeding roller, a sheet feeding tray on which sheet materials are stacked And side regulating means capable of moving the sheet material in the left-right direction with respect to the conveying direction, and the sheet material guide surface position of the side regulating means is in the feeding direction with respect to the central position of the sheet feeding tray on which the sheet material is stacked. A sheet feeding device having different height positions in the direction perpendicular to the sheet feeding device. 2. In addition to the original tray, a guide member is provided for forming a flat portion near the center of the front end of the sheet material when the intermediate plate urges the sheet material toward the sheet feeding roller. The sheet feeding device according to claim 1.