JP3258142B2 - Sheet material feeding device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet feeding apparatus applied to an image forming apparatus, and more particularly to a sheet feeding apparatus characterized by a pressing mechanism for a stacking plate on which a sheet is stacked.

[0002]

2. Description of the Related Art As a conventional example of this type of sheet feeding apparatus, Japanese Patent Application Laid-Open No. 3-256927 discloses a detecting means which detects a load applied to a sheet feeding roller, a stacked thickness of sheets, and a sheet size. In addition, there has been proposed a technique for adjusting the load of the pressure spring to make the sheet feeding pressure constant. In addition, Japanese Unexamined Patent Publication No.
Japanese Patent Publication No. 280742 proposes a technique for stabilizing the sheet feeding pressure by using a pressure lever that acts when the stacking amount is large and does not act when the stacking amount is small according to the rising position (sheet stacking amount) of the sheet stacking plate. Have been.

[0003]

In the prior art of the prior art, the load of the pressure spring is controlled by a motor in order to keep the paper feeding pressure constant. There is a need for a detecting means for detecting the stacking thickness, paper size, pressure applied to the feed roller shaft, and the like, and the cost is greatly increased. In the latter case, the paper feed pressure is obtained by a plurality of pressure springs. However, since the pressing force is applied via a plurality of transmission members, the configuration becomes complicated, and the paper on the loading table becomes complicated. Therefore, there is a drawback that the intended paper feed pressure cannot be stabilized against a weight change based on the paper size.

SUMMARY OF THE INVENTION An object of the present invention is to provide a sheet feeding apparatus capable of performing stable sheet feeding without double feeding and non-feeding by suppressing variations in sheet feeding pressure.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a sheet material feeder having sheet material feeding means, and a sheet material storage section which is mounted so as to be able to be taken in and out of the sheet material feeder to process the sheet material. In the sheet material feeding device for sequentially feeding the sheet material stored in the sheet material storage unit to the apparatus body by the sheet material feeding unit, the sheet material storage unit is configured to stack the sheet material and move the sheet material up and down. a rotatable stacking plate, the width direction regulating member movable according to the size of the sheet material, to press the stacking plate upwardly, and the loading plate in accordance with the movement position of the width direction regulating member A first elastic member held at a disengaged position of the first elastic member, a second elastic member provided inside the first elastic member in the sheet material width direction and pressing the stacking plate upward , Transfer of the width direction regulating member
Depending on the turned position, before Symbol a moving member that moves to engage the disc-shaped member held by the first elastic member, the constructed integrally with the sheet material housing portion, the movable member and the first And a lock member comprising a pressing member for a moving member that constantly presses in the direction of the elastic member.
The moving member of the locking means moves accordingly, and the loading plate
When the button is depressed, the moving member of the locking means
The lock member is engaged with a disk-shaped member of the elastic member.
Disengagement position of the first elastic member with the loading plate
Is achieved by the first means.
In the first means, the first elastic member and the second elastic member are achieved by a second means having different spring constants.

[0006]

In the first means, the loading plate is pushed down.
The locking means according to the movement position of the width direction regulating member
Moving member moves and engages with the disc-shaped member of the first elastic member.
The first elastic member is separated from the loading plate by the locking means.
Since so as to be held in the engaged position, it is possible to reliably hold the first elastic member in the non-engaged position. The second
In the means, the range of the sheet feeding pressure can be reduced by changing the spring constants of the first elastic member and the second elastic member, even if the loading amount of various size papers changes.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a partially cutaway front view showing a schematic configuration of a sheet material feeding apparatus according to an embodiment of the present invention. FIG. 2 is a vertical sectional view showing a schematic configuration of the sheet material feeding apparatus when A3 size sheets are stacked. (Direction orthogonal to the sending direction).
4 size sheet (vertical) diagram showing a longitudinal schematic configuration of a sheet feeding apparatus when loaded with, FIG. 4 is Saidofu
FIG. 5 is a main part perspective view of the sheet material feeding device in the vicinity of the main member, FIG. 5 is a longitudinal sectional view of the main portion showing a locked state of a first elastic member of the sheet material feeding device, and FIG. 9 is a longitudinal sectional view of a main part showing the unlocked state of the elastic member, FIG. 7 is a comparison characteristic diagram of a range of sheet feeding pressure, FIG. 8 is a schematic diagram for explaining sheet separation conditions in a corner claw sheet feeding system, and FIG. 7 is a comparison characteristic diagram of a double feed area and a non-feed area.

As shown in FIG. 1, a tray (sheet material storage section) 1 can be set at a predetermined position on a main body 2 and can be pulled out to the front (front loading type). The tray 1 is provided with a loading plate 3 on which sheets S are loaded, which is rotatably supported with a part of the tray 1 as a fulcrum 3a, and is held at a lower portion when the tray 1 is pushed down. In the tray 1, first pressure springs (first elastic members) 4a, 4a, and the first pressure springs 4a
Second pressure springs (second elastic members) 4b, 4b are provided on the inner side in the sheet width direction, and the first pressure springs 4a, 4a and the second pressure springs 4b, 4b are provided.
The loading plate 3 is pushed upward by b, and the sheet S on the loading plate 3 is pressed by the feed roller 8. That is, the free end of the loading plate 3 is pressed upward by the first pressure spring 4a and the second pressure spring 4b. In the tray 1, a side fence (width direction regulating member) is provided on a sheet end surface orthogonal to the sheet S traveling direction.
5 and 5 are provided and can be moved according to the sheet size. These side fences 5 and 5 have a fulcrum 6
Corner pawls 6, 6 rotatable about a are provided, and the pawls 6, 6 are positioned at the leading edge of the stacked sheets S, and the fed sheets S are separated one by one. It is possible. The mechanism of sheet separation by the corner claws 6 will be described later. Disc-shaped members 13, 13 each having a flange 13a are fixedly covered on the upper end of the first pressure spring 4a, and the first pressure springs 4a, 4a are fixed to the disc-shaped members 13, 13, respectively. The loading plate 3 is pushed up via the.

Above the sheet S, there is provided a feed roller (sheet material feeding means) 8 pivotally supported by the main body 2, and the feed roller 8 receives a driving force of a driving source (not shown) and has a predetermined timing. To feed the sheet S to the first conveying roller pair 10 side. The sheet S sent out by the feed roller 8 is sent from the first conveying roller pair 8 to the registration roller pair 12 via the second conveying roller pair 11 along the turn guide 9, and thereafter,
The sheet is conveyed from the registration roller pair 12 to the next step at a predetermined timing.

As shown in FIGS. 4 to 6, the moving member 14 constituting the locking means is provided so as to be movable at a predetermined position by guide pieces 1b, 1b and the like formed integrally with the tray 1. The pressure spring 4a can be separated from and contacted with the pressure spring 4a. The movable member 14 has an engaging portion 14 provided at the tip thereof and capable of engaging with the flange portion 13a of the disc-shaped member 13.
b, and the protruding portion 1 protruding from the upper surface on the side opposite to the engaging portion 14b
4a is provided. The flange 1 of the disc-shaped member 13
The lower edge of the lower surface 3a and the upper edge of the engaging portion 14b are formed with roundness so that they can be smoothly engaged.

The tray 1 has an elastic piece 1a.
The moving member 14 is pressed in the direction of the first pressure spring 4a by the elastic force of the elastic piece 1a. The moving member 14 is the first pressing spring 4
In the state in which the moving member 1 is moved in the direction shown in FIG.
The disk-shaped members 13,
When the loading plate 3 is pressed down in such a state, the first pressure spring 4 is disengaged from the loading plate 3 (in a state where the first pressure spring 4 is compressed). ).

A horizontally extending piece 7 is formed integrally with the side fence 5, and the horizontally extending piece 7 comes into contact with the protrusion 14 a of the moving member 14. In addition, the horizontal extension piece 7
, The collision detecting portion 14a and the side abutting the tapered portion 7a (FIG.
6) is formed, and the drive transmission direction of the horizontally extending piece 7 and the moving member 14 is changed by 90 ° by the tapered portion 7a. Therefore, when the side fence 5 is moved from the inside (small size position) of the tray 1 to the outside (large size position) when stacking A3 size sheets, the moving member 14 is opposed to the elastic piece 1a by the tapered portion 7a. It is moved in a direction away from the disk-shaped member 13. Thereby, as shown in FIG. 6, the first pressure spring 4a is released from the engaging portion 14b of the moving member 14 and becomes free. A in this tray 1
When three size sheets are stacked, as shown in FIG.
A first pressure spring 4a and a second pressure spring 4
The sheet S on the stacking plate 3 is pressed against the feed roller 8 by b.

On the other hand, when the side fence 5 is moved from the outside of the tray 1 to the inside when stacking A4 size sheets (vertical), the moving member 14 approaches the disk-shaped member 13 by the pressing force of the elastic piece 1a. In the direction, and can be engaged (locked) with the flange 13a of the disc-shaped member 13. When an A4 size sheet (vertical) is stacked, as shown in FIG. 3, the first pressure spring 4a is held at a position where the first pressing spring 4a is not engaged with the stacking plate 3 by a locking means described later. Is pressed against the feed roller 8 by the second pressure spring 4b.

Here, the operation of the moving member 14 will be described with reference to FIGS. 1 to 3 and FIGS. First, a case where the first pressure spring 4a is locked (the side fence 5 is at the small size position) will be described. In the locked (or locked) state, the horizontally extending piece 7 of the side fence 5 is not in contact with the protrusion 14a of the moving member 14 (that is, the side fence 5 is inside the tray 1 shown in FIG. 2). The moving member 14 is pressed by the displacement force of the elastic piece 1a and is located closer to the first pressure spring 4a. When the loading plate 3 in the state shown in FIGS. 1 and 2 is pushed down in such a state, the disc-shaped member 13 held by the first pressure spring 4a is also pushed down,
The flange 13a of the disc-shaped member 13 is
4b. Further, when the loading plate 3 is pushed down, the moving member 14 is moved in a direction away from the first pressure spring 4a against the elastic piece 1a by the flange portion 13a of the disk-shaped member 13, and the engagement of the moving member 14 is reduced. The flange portion 13a of the disc-shaped member 13 reaches the lower surface of the joint portion 14b, and the moving member 14 moves in the direction of the first pressure spring 4a by the elastic piece 1a to engage with each other, as shown in FIG. The first pressure spring 4a is held at the lock position in a compressed state.

Next, a case where the side fence 5 is moved from the small size position to the large size position will be described. As described above, when the side fence 5 is in the small size position, the tapered portion 7a of the horizontally extending piece 7 of the side fence 5 does not act, so the moving member 14 is pressed by the elastic piece 1a. At the lock position (see FIG. 5) close to the first pressure spring 4a, the first pressure spring 4a is compressed and does not push up the loading plate 3 as described above. When the side fence 5 at the small size position is moved to the large size position, that is, from the inside of the tray 1 to the outside, the horizontal extension pieces 7 of the side fence 5 are moved.
The tapered portion 7a contacts the protruding portion 14a of the moving member 14, and moves the moving member 14 in a direction away from the first pressure spring 4a against the elastic piece 1a. Due to the movement of the moving member 14, the engagement between the engaging portion 14b of the moving member 14 and the flange 13a of the disc-shaped member 13 is released, and the first pressure spring 4a is in a free state, and The pressure spring 4a comes into contact with the loading plate 3 to push up the loading plate 3 (see FIG.
6) .

Next, a case where the side fence 5 is at a large size position will be described. At the time of large size, the side fence 5 is located outside as shown in FIG.
In this state, the tapered portion 7a of the horizontally extending piece 7 of the side fence 5 is
4A, the moving member 14 is moved in a direction away from the disc-shaped member 13 against the elastic piece 1a via the protruding portion 14a which comes into contact with the tapered portion 7a of the horizontally extending piece 7.
It is in the state of. 6, the engaging portion 14b of the moving member 14 is retreated outside the movement locus of the disk-shaped member 13 fixed to the first pressing spring 4a. Is pressed down, the first pressure spring 4a is not locked by the engaging portion 14b of the moving member 14. When the side fence 5 is moved from the large size position to the small size position, the tapered portion 7a of the horizontally extending piece 7 of the side fence 5 comes off the projection 14a of the moving member 14, and the moving member 14
a, and is moved in a direction approaching the first pressure spring 4a to be in a lockable state (see FIG. 5).
See) .

As described above, the first pressure spring 4a
Side fence 5 of the second pressure spring 4b
Is in the small size position, the first pressure spring 4a
However, by setting the first pressure spring 4a and the second pressure spring 4b to predetermined values so that the spring constants are different from each other, the range of the sheet feeding pressure can be further reduced. It is possible to do. FIG. 7 shows the comparison characteristics of the range of the paper feed pressure, and shows the A3 size sheet and the A3 size sheet.
FIG. 7 shows a state (example) of the sheet feeding pressure obtained from 0 to 300 sheets for a 4 (longitudinal) size sheet. As is clear from FIG. 7, the range of the sheet feeding pressure of the conventional machine (dashed line) is shown. compared to,
In the present embodiment (solid line), the range of the sheet feeding pressure can be set small.

Next, sheet separation in the corner claw paper feeding system will be described with reference to FIGS. In this paper feeding method, the conditions for separating the first sheet and the second and subsequent sheets and the conditions for sending out the first sheet are fundamental as described below. 1. The separation conditions for performing separation using the buckling of a sheet are as follows: Pk> P (μp−μp ′) = P · Δμp; The condition for feeding the first sheet is as follows: P (μr−μp)> R + Pk. Here, Pk: corner pawl (6) blocking force (buckling resistance of sheet) R: output from corner pawl (6) P: roller (8) pressing force μr: friction coefficient between roller (8) and sheet μp : Friction coefficient between sheets Δμp: friction coefficient difference between sheets. FIG. 9 shows the relationship between the double feed and the non-feed in the form of the above conditional expression. FIG. 9 shows a conventional type (1
Paper feed pressure is set by a different type of pressurizing spring) and the paper feed pressure range B in the present embodiment.
The boundary of the double feed area is P = (1 / Δμp) · Pk. The boundary of the non-feed area is P = {1 / (μr-μp)} · Pk-R. As is apparent from FIG.
The margin for non-feeding can be improved.

In the above-described embodiment, a sheet material feeder having a feed roller 8 is provided.
A tray 1 which is mounted so as to be able to be taken in and out of the sheet material feeder unit, and which feeds the sheets S stored in the tray 1 to a main body 2 for processing the sheets S by a feed roller 8 sequentially. In the device, tray 1
Is a loading plate 3 on which sheets S can be loaded and turned vertically, and a side fence 5 which can be moved according to the size of the sheets S.
A first pressing spring 4a capable of pressing the loading plate 3 in an upward direction and being held in a disengaged position with the loading plate 3 in accordance with the moving position of the side fence 5, and a first pressing spring 4a, a second pressure spring 4b is provided on the inner side in the width direction of the sheet S and presses the stacking plate 3 upward.
Since a can be selected, the contact pressure between the feed roller 8 and the sheet S can be stabilized according to the sheet size, and the margin for double feed and non-feed can be improved. In the embodiment, when the loading plate 3 is pushed down, the first
The first pressure spring 4a can be locked by the lock means (moving member 14) when the loading plate 3 is depressed because the locking means (moving member 14) for holding the pressure spring 4a at the inoperative position is provided. Therefore, the sheet size can be changed and the sheet can be easily replaced. Further, in the above embodiment, when at least the side fence 5 is at the position corresponding to the maximum size in the width direction of the sheet size, the first pressure spring 4a can be operated upward, so that the maximum size paper ( In the width direction, the first pressure spring 4a acts on the stacking plate 3, so that the sheet feeding pressure (contact between the feed roller 8 and the sheet S) is applied to A3 size and A4 size sheets which are usually used frequently. Pressure) range can be set small. Further, in the above embodiment, the locking means of the first pressure spring 4a includes a moving member 14 which moves so as to be able to engage with the disk-shaped member 13 held by the first pressure spring 4a; Since the elastic member 1a is integrally formed with the tray 1 and constantly presses the moving member 14 in the direction of the first pressure spring 4a, the first pressure spring 4
Since the moving member 14 is engaged with the peripheral portion 13a of the disc-shaped member 13 held at the position a, the first pressure spring 4a can be reliably held at the non-operating position. In the embodiment, the first pressure spring 4a and the second pressure spring 4b are set to have different spring constants, so that the first pressure spring 4a and the second pressure spring 4a are different from each other. By changing the spring constant of 4b, the range of the sheet feeding pressure can be reduced even if the stacking amount of various size papers changes.

[0020]

According to the first aspect of the present invention, the loading plate is
When it is pushed down, according to the movement position of the width direction regulating member,
The moving member of the locking means moves and the first elastic member has a disk shape.
Engage with the member and load the first elastic member by the locking means
Because it is held at the position where it does not engage with the plate ,
By the lock member can retain the first elastic member in the non-engaged position. According to the second aspect of the present invention, the first
By changing the spring constants of the elastic member and the second elastic member, the range of the sheet feeding pressure can be reduced even if the stacking amount of various size papers changes.

[Brief description of the drawings]

FIG. 1 is a partially cutaway front view showing a schematic configuration of a sheet feeding apparatus according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a schematic configuration of a sheet material feeding device when A3 size sheets are stacked, in a longitudinal section (a direction orthogonal to a feeding direction).

FIG. 3 is an explanatory diagram illustrating a schematic configuration of a sheet material feeding apparatus when A4 size sheets (vertical placement) are stacked, in a longitudinal section;

FIG. 4 is a perspective view of a main part of a sheet material feeding device near a side fence .

FIG. 5 is a longitudinal sectional view of a main part showing a locked state of a first pressure spring of the sheet feeding device.

FIG. 6 is a longitudinal sectional view of a main part showing a non-locked state of a first pressure spring of the sheet feeding device.

FIG. 7 is a comparison characteristic diagram of a range of a sheet feeding pressure.

FIG. 8 is a schematic diagram for explaining sheet separation conditions in a corner claw sheet feeding method.

FIG. 9 is a comparison characteristic diagram of a double feed area and a non-feed area.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Tray (sheet material storage part) 3 Stacking plate 4a 1st press spring 4b 2nd press spring 5 Side fence (width direction restricting member) 7 Horizontal extension piece 8 Feed roller (sheet material feeding means) 13 Disk-shaped member 14 Moving member

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B65H 1/24 B65H 1/04

Claims (2)

(57) [Claims] 1. A sheet processing apparatus comprising: a sheet material feeder having sheet material feeding means; and a sheet material storage section which is mounted so as to be able to be taken in and out of the sheet material feeder. In the sheet material feeding device for sequentially feeding the sheet material stored in the material storage unit by the sheet material feeding unit, the sheet material storage unit is configured to load a sheet material and rotate vertically. a width direction regulating member movable according to the size of the sheet material, to press the stacking plate in an upward direction, is held in the disengaged position of said loading plate according to the moving position of the width direction regulating member that a first elastic member, than the first elastic member provided on the inner side of the sheet material width direction, and a second elastic member for pressing upward the stacking plate, the moving position of the width direction regulating member depending on the previous SL held by the first elastic member And a pressing member for the moving member, which is integrally formed with the sheet material storage portion and constantly presses the moving member in the direction of the first elastic member. comprising a comprising locking member, said locking means in accordance with the movement position of the width direction regulating member
When the moving member moves and pushes down the loading plate,
The moving member of the lock means is a disk-shaped member of the first elastic member.
The first elastic member is engaged with the member, and
The member is held at a position not engaged with the loading plate.
A sheet material feeding device. 2. The sheet feeding device according to claim 1, wherein the first elastic member and the second elastic member have different spring constants.