JPH0524284A - Sheet transfer device - Google Patents

Abstract

PURPOSE:To eliminate the deflection of the leading edge of a sheet material due to buckling thereof without lowering the workability at feeding the sheet material in a sheet transfer device for feeding a sheet material from a steeply inclined feeding tray. CONSTITUTION:A middle board 6 which is pivotable about an axis 11 and a guide member 13 are interposed between a steeply inclined sheet feeding tray 3 and a sheet feeding roller 20. The board 6 is urged toward the roller 20 by a compressing spring 12, while the member 13 is urged against the board 6 by an urging member 17. A spacer 16 is interposed between the board 6 and the member 13 to maintain both at a predetermined interval D. Since the member 13 follows the motion of the board 6, the interval D is maintained constant. As a result, even if the board 6 is positioned at a feeding location (solid line) or supplying location (broken line), it guides together with the member 13 a sheet material P so as to maintain the leading edge thereof in a planar state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet conveying apparatus for feeding a sheet material from an inclined sheet feeding tray to a main body of an image forming apparatus such as a copying machine. The present invention relates to a guide mechanism that is interposed between a sheet feeding roller and a sheet feeding roller to guide the sheet material to the sheet feeding roller.

[0002]

2. Description of the Related Art There is known a sheet conveying device provided in an image forming apparatus such as a copying machine, which separates and conveys a sheet material by using a sheet feeding roller and a friction pad.

This type presses the friction pad against the outer peripheral surface of the paper feed roller via a pressing member and allows the sheet material to pass through the nip portion between the two. The friction coefficient between the paper feed roller and the sheet material. Is set to be larger than the friction coefficient between the friction pad and the sheet material, so that a plurality of sheet materials are prevented from being double-fed and only one sheet is correctly 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.

Recently, there has been a demand for downsizing of copying machines and the like, and as one means for realizing this,
A method of mounting the paper feed tray at a steep angle with respect to the apparatus main body, that is, at a large inclination angle close to a right angle with respect to the horizontal plane to reduce the occupied area is adopted.

At this time, 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 paper feed tray. However, since the paper feed tray has a steep angle, the weight of the sheet material itself is reduced. As a result, a wavy flexure is generated at the front end portion due to buckling, and there is a fear that the sheet material cannot be correctly fed to the feeding roller and the friction pad. In order to prevent this, in general, a guide member that guides the upper surface side of the sheet material is fixedly disposed so as to face the middle plate that supports the lower surface of the front end portion of the sheet material, and the distance between the two is fixed. Is set to a predetermined interval that is not so wide that the front end portion of the sheet material is lightly sandwiched, and the posture thereof is prevented from being greatly disturbed.

[0007]

However, it is not always sufficient to prevent the buckling of the front end portion of the sheet material by only disposing the guide member facing the intermediate plate as described above. I couldn't say it.

That is, when replenishing the sheet material onto the sheet feeding tray, it is necessary to separate the intermediate plate from the sheet feeding roller and sandwich the sheet material between the two. At the same time, the sheet is separated from the guide member, and the space between the intermediate plate and the guide member is widened, so that the front end portion of the sheet material whose regulation is relaxed easily buckles. On the other hand, when the distance between the middle plate and the guide member is set to be small in advance in consideration of the case where the middle plate is separated from the paper feed roller, the guide member interferes with the insertion of the sheet material when the sheet material is replenished. However, there is a risk that it will hinder the replenishment work.

Therefore, according to the present invention, the guide member for guiding the upper surface side of the sheet material is moved in association with the movement of the intermediate plate, thereby facilitating the replenishment work of the sheet material and the front end of the sheet material. It is an object of the present invention to provide a sheet material feeding device in which buckling of a portion is well prevented and a sheet material is smoothly fed.

[0010]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances. For example, referring to FIG. 1, a sheet feeding tray (3) and a sheet feeding tray which are inclined forward and downward are shown. An oscillating middle plate (6) that supports the front end of the sheet material (P) from the back side and biases the sheet material (P) toward the paper feed roller (20) is interposed between the roller (20) and the roller (20). , The intermediate plate (6)
A sheet material (P) having a front end portion sandwiched between the sheet feeding roller (20) and the sheet feeding roller (20) by feeding the sheet material (P) by rotation of the sheet feeding roller (20); 6) a swingable guide member (13) that guides the front end of the sheet material (P) from the front side, and a predetermined interval between the guide member (13) and the intermediate plate (6). The spacer (16) held in (D) and the guide member (13) are urged toward the intermediate plate (6) so that the movement of the guide member (13) changes to the movement of the intermediate plate (6). And a biasing member (17) for making the follower follow.

In this case, the inclination angle (θ) of the front-down paper feed tray (3) with respect to the horizontal plane (H) is 4
It is good to set it between 5 degrees and 70 degrees.

[0012]

According to the above construction, the space between the intermediate plate (6) and the guide member (13) is maintained at the predetermined space (D) through the spacer (16), so that the paper feed roller (20) is used. At the time of feeding the sheet material (P), the front end portion of the sheet material (P) is appropriately regulated by the guide member (13) and the intermediate plate (6) from both front and back sides, and buckling does not occur. Absent.

On the other hand, when replenishing the sheet material (P),
The intermediate plate (6) is to be separated from the paper feed roller (20), but at this time, the guide member (13) is urged by the biasing member (1).
Since it is urged toward the middle plate (6) by 7),
Since the guide member (13) moves following the intermediate plate (6) and the spacer (16) is interposed between the guide member (13) and the intermediate plate (6), the distance between them is the same as the above-mentioned sheet material (P) feeding. It can maintain almost the same as when it was sent. This prevents the front end portion of the sheet material (P) from being greatly deformed due to buckling even when the sheet material (P) is replenished.

Moreover, the middle plate (6) of the guide member (13)
Since the follow-up motion to the is performed without manual intervention, the user or the like performs a special operation in order to maintain the space between the guide member (13) and the intermediate plate (6) at a predetermined space (D). You don't have to.

The reference numerals in the parentheses are for the purpose of comparing the drawings, and do not limit the structure of the present invention.

[0016]

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

FIG. 1 shows a state in which a sheet conveying device 1 is mounted on a main body C of a copying machine or the like.

The sheet conveying apparatus 1 is provided with a sheet feeding tray 3 protruding from a frame 2 fixed to the apparatus main body C.

The paper feed tray 3 is formed of a plate-like member, and the mounting surface 5 on the upper surface side on which the sheet material P is mounted is finished to be smooth. The paper feed tray 3 is attached to the frame 2 so as to incline frontward (left side in FIG. 1 is front and right side is rear), and an inclination angle θ formed by the mounting surface 5 and the horizontal plane H. Is set to 60 °. An intermediate plate 6 is arranged on the lower end side of the paper feed tray 3.

The middle plate 6 is formed by a bottom plate 9 having a gentle bent portion 7 in the center, and a pair of side plates 10 projecting upward from both left and right ends on the rear end side of the bottom plate 9. Through holes 10a are formed in each side plate 10, and a shaft 11 fixed to the frame 2 passes through these through holes 10a. The entire middle plate 6 is indicated by the arrow K by this shaft 11.
It is swingably supported in one direction. A compression spring 12 having one end fixed to the frame 2 is connected to the back 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. Middle plate 6
A guide member 13 is disposed above the.

The guide member 13 is arranged so as to face the bottom plate 9 of the intermediate plate 6, and its rear end side is similarly swingably supported by the above-mentioned shaft 11 which swingably supports the intermediate plate 6. ing. A roller 15 is provided on the lower surface side of the guide member 13.
Is rotatably attached to the shaft. Spacers 16 are fixed to the left and right ends on the front end side of the guide member 13, respectively. When a part of the spacer 16 abuts on the intermediate plate 6, the distance between the intermediate plate 6 and the guide member 13 is a predetermined distance D. Trying to hold. In other words, when the front end portion of an appropriate number of sheet materials P is inserted between the intermediate plate 6 and the guide member 13, the predetermined distance D is such that extreme bending due to buckling does not occur in this portion. The front end portion of the sheet material P is supported in a substantially flat shape so that the sheet is not hindered from being fed. In addition, the spacer 16 is formed by
Instead of fixing to the side, it may be fixed to the side of the middle plate 6. It suffices that the spacer 16 separates the guide member 13 and the intermediate plate 6 by a predetermined distance D.

The upper end of the swingable guide member 13 is connected to the other end of an urging member 17 having one end fixed to the frame 2. The urging member 17 connects the guide member 13 to the middle plate 6.
Is urged towards. As a result, the guide member 13 follows the movement of the intermediate plate 6. That is, the guide member 13 and the middle plate 6 are independently swingably supported by the common shaft 11, and the guide member 13 is urged toward the middle plate 6 by the urging member 17. The intermediate plate 6 is biased toward the guide member 13 by the compression spring 12. Then, the guide member 13 and the intermediate plate 6 are provided with a spacer 16
Are opposed to each other with a predetermined distance D therebetween. Guide member 13
The intermediate plate 6 and the intermediate plate 6 are pressed against each other via a spacer 16, and in the natural state of the biasing member 17 and the compression spring 12, the tip end portion of the intermediate plate 6 will be described later as shown by the solid line in FIG. It is stable when pressed against the paper feed roller 20. Therefore, when the front end of the middle plate 6 is pushed down and separated from the paper feed roller 20, the compression spring 12 shortens, while the urging member 17 extends, so that the guide member 13 follows the movement of the middle plate 6. It moves in the same way. At this time, since the guide member 13 and the middle plate 6 have the above-described shaft 11 as a common swing center, even if the middle plate 6 moves, the relative positional relationship between the two does not change. In other words, regardless of the movement of the middle plate 13,
A predetermined distance D between the guide member 13 and the middle plate 6 is ensured.

The paper feed roller 20 with which the intermediate plate 6 abuts is attached to a paper feed roller shaft 21. Paper feed roller shaft 21
The left and right ends of the sheet are rotatably supported by the frame 2 (see FIG. 2), and the sheet feeding roller 20 is rotatably driven by a driving device (not shown) via the sheet feeding roller shaft 21.

A separation pad 23 is pressed from below on the outer peripheral surface 22 of the paper feed roller 20 (see FIG. 1), and a nip portion N is formed between the two. The separation pad 23 is fixed to the upper surface of the front end portion of an arm 26 having a swing center 25 at the rear end, and the arm 26 is upwardly moved by a compression spring 27 interposed between the front end of the arm 26 and the frame 2. As it is urged, it is pressed against the outer peripheral surface 22 of the paper feed roller 20 with an appropriate pressure. The sheet material P fed by the rotation of the sheet feeding roller 20 passes through the nip portion N, but at this time, the friction coefficient μ1 between the outer peripheral surface 22 of the sheet feeding roller 20 and the sheet material P is separated. Pad 23 and sheet material P
Is set to be larger than the friction coefficient μ2 between the sheet material P and the friction coefficients μ1 and μ2.
It becomes larger than 3, that is, each friction coefficient μ1, μ2, μ
In the period of 3, μ1>μ2> μ3 is established. As a result, two or more sheet materials P are put in the nip portion N.
Even when the sheet enters, the outer peripheral surface 2 of the sheet feeding roller 20
Only the uppermost sheet material P that contacts 2 is correctly fed.

The sheet material P thus fed is
The sheet is fed while being guided by a conveyance guide 29 formed in the vicinity of the nip portion N, but on the rear end side of the conveyance guide 29, slightly ahead of the leading edge of the intermediate plate 6 and almost along the locus of movement of this leading edge. A sheet front end abutting surface 30 that is inclined upward and upward is formed. The sheet front end abutting surface 30 regulates the front end position of the sheet material P at the time of replenishment, and is formed substantially at right angles to the mounting surface 5 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 downward about the shaft 11 to the replenishment position (two-dot chain line in FIG. 1). After the sheet P is replenished, the sheet P is returned to the feeding position shown by the solid line in the figure.

Next, the operation of the above embodiment will be described.

First, the intermediate plate 6 is swung about the shaft 11 and is arranged at the replenishment position shown by the solid line in FIG. At this time, the guide member 13 biased by the biasing member 17 is
It swings around the shaft 11 following the intermediate plate 6 and maintains the distance from the intermediate plate 6 at a predetermined distance D via the spacer 16.

Next, several sheets of material P are placed on the paper feed tray 3, the leading end portion is inserted between the shaft 11 and the bottom plate 9 of the middle plate 6, and the leading end portion is lowered along the bottom plate 9. Then, the sheet tip abutting surface 30 is brought into contact. At this time, the front half portion of the middle plate 6 and the guide member 13 is tapered more narrowly in the bent portion 7 of the bottom plate 9 than the rear half portion, and moreover, the roller is rotatable so as to face the bent portion 7. Since the sheet material 15 is provided, the leading end portion of the sheet material P is smoothly and inserted between the intermediate plate 6 and the guide member 13 in a posture in which the sheet material P is maintained flat.
Subsequently, when the middle plate 6 is returned to the feeding position, the leading edge of the sheet material P rises along the sheet leading end abutting surface 30, and is sandwiched between the middle plate 6 and the sheet feeding roller 20. At the same time, the sheet is placed in the nip portion N between the sheet feed roller 20 and the friction pad 23, and the feeding preparation is completed.

Thereafter, when the paper feed roller 20 is rotated in the direction of arrow K2, only the uppermost one sheet material P is separated from the other sheet materials P and is fed.

In this way, when the intermediate plate 6 is moved to the replenishment position, the guide member 13 moves following it, and the predetermined distance D between the two is unequal when the guide member 13 is fixed. Unlike the case where the front end portion of the sheet P is buckled, the front end portion of the sheet material P is well prevented from being greatly distorted.

The inclination angle θ of the paper feed tray 3 is set to 60 degrees in this embodiment, but from 45 degrees to 7 degrees.
If it is set between 0 degrees, almost the same effect can be obtained. The optimum value of the inclination angle θ is slightly different depending on the thickness and size of the sheet material P, but based on the thickness and size of the sheet material P generally used in an ordinary office or the like, The angle between 45 and 70 degrees described above is preferable. When the inclination angle θ is 45 degrees or less, the horizontal projection area of the sheet feeding tray 3 becomes large, and the effect on downsizing of the entire copying machine is reduced. On the other hand, when it exceeds 70 degrees, the sheet feeding is The posture of the sheet material P when it is stacked on the tray 3 is not only unstable, but also the entire sheet is likely to buckle.

[0033]

As described above, according to the present invention, the guide member for guiding the front end portion of the sheet material from the front surface side in cooperation with the intermediate plate supporting the front end portion of the sheet material from the back surface side,
By following the movement of the middle plate,
Since the distance between the middle plate and the guide member can be maintained at a suitable predetermined distance regardless of the position of the middle plate, harmful buckling occurs at the front end of the sheet material during feeding and replenishment of the sheet material. It is possible to guide the sheet material in a flat manner without the need to carry out, and the sheet material can be conveyed smoothly.

Furthermore, there is no fear that the gap between the intermediate plate and the sheet material will be unduly widened, and the gap between the two can be set appropriately in advance. The part can be inserted smoothly without being caught by the middle plate or the guide member.

[Brief description of drawings]

FIG. 1 is a vertical sectional side view showing a sheet conveying device.

FIG. 2 is a view on arrow A in FIG.

FIG. 3 is an operation explanatory view of the sheet conveying device.

[Explanation of symbols]

1 sheet conveying device 3 paper trays 6 Middle plate 13 Guide member 16 spacers 17 Biasing member 20 paper feed rollers D predetermined interval H horizontal plane P sheet material θ inclination angle

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 in which a sheet is interposed and a front end portion is sandwiched between the intermediate plate and the sheet feeding roller and is fed by rotation of the sheet feeding roller, A swingable guide member that guides the front end portion of the sheet material from the front side, a spacer that holds the guide member and the intermediate plate at a predetermined interval, and a biasing force of the guide member toward the intermediate plate. And a biasing member that causes the movement of the guide member to follow the movement of the intermediate plate. 2. The sheet conveying apparatus according to claim 1, wherein an inclination angle of the front-down paper feed tray with respect to a horizontal plane is between 45 degrees and 70 degrees.