JPH0248341A - Sheet feeding device - Google Patents

Abstract

PURPOSE:To keep a contact pressure of a forward roller with a reverse roller approximately at a specified value by a method wherein the intersection angle of an energizing direction with a straight line for interconnecting the energizing action point of a rocking member and the fulcrum center of the rocking member. CONSTITUTION:When sheets P are fed, in order, from a feed cassette 6, the diameter of a reverse roller 4 is radially decreased by means of friction. Through gradual upward rocking of a rocking lever 31 around a support axle 30 along with the decrease of the diameter of the reverse roller, an expandable member 50 is expanded through the energizing force of a compression spring 52, and along with the expansion, the energizing force of the compression spring 52 is decreased gradually. In this case, since an energizing member 5 is located at an angle of 40 - 80 deg. of the energizing direction with a straight line (l) for interconnecting the energizing action point of the rocking member 3 and the center of the support axle 30, an effective moment radius is increased with the decrease in the energizing force of an energizing member 5 due to wear of the reverse roller. This constitution keeps the moment of a force exerted on the support axle 30 of the rocking member 3 approximately at a specified value, and the contact pressure of the reverse roller 4 with a forward roller 2 is also kept approximately at a specified value.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a paper feeding device used in a copying machine or the like.

[Conventional Pinching Technique] Conventionally, the paper feeding device of a copying machine has been designed to prevent two or more sheets of paper from being sent out while being overlapped! A type using the sabunki method is known. This paper feeding device, for example, as shown in FIG. 5, feeds out the paper Po! A forward rotation roller 102 to be fed, a first working member 103 having a support shaft 103a arranged parallel to the rotation axis of the forward rotation roller 102 and swinging around the support shaft 103a, and a rotatable member 103 in the swing member 103. while being held in place and in contact with the normal rotation roller 102,
It includes a reversing roller 104 that applies a constant torque in a direction opposite to the conveying direction of the paper Po, and an erecting member 105 that has one end locked to a swinging member 103 and biases the reversing roller 104 toward the forward rotating roller 102. ing.

Then, if the paper [ ) o is not between the rollers 102 and 104 and when one sheet of paper Po is fed, the paper [ ) o is between the rollers 102 and 104 or the paper P.

The frictional force between the rotation roller 104 and the rotation roller 104 overcomes the torque, and the reverse rotation roller 104 follows the normal rotation roller 102. As a result, the reverse rotation roller 104 rotates in the normal direction without slipping with the normal rotation roller 102 and the paper Po. Furthermore, when two or more sheets of paper Po are fed between both rollers 102 and 104, since the frictional force between the sheets is weaker than the torque, the reversing roller 104 rotates in the reverse direction, and the second and subsequent sheets The paper Po is pushed back in the direction opposite to the conveyance direction to separate it, and only the one paper Po in contact with the normal rotation roller 102 is sent out.

Note that the biasing member 105 that biases the reverse rotation roller 104 against the normal rotation roller 102 has a biasing point Co on the swinging member 103 and a support shaft 1 so that the biasing force of the biasing member 105 is maximized.
The biasing force direction Fo is arranged at right angles to the straight line λ0 connecting the center Δ0 of 03a.

[Problems to be Solved by the Invention] By the way, in the friction separation type, the frictional resistance of the reversing roller is large, so it wears out quickly, and since the roller diameter of the reversing roller used is generally small, the roller diameter decreases due to wear. It has the disadvantage of a high ratio. Due to its structure, the biasing force of the biasing member decreases as the O-roller diameter of the reversing roller decreases. For this reason, the contact pressure of the reverse rotation roller with respect to the forward rotation roller gradually decreases, resulting in a problem in that the frictional separation performance deteriorates significantly.

The present invention has been devised in view of the above-mentioned circumstances, and its purpose is to provide a paper feeding device that can maintain substantially constant contact pressure of the reverse rotation roller with respect to the forward rotation roller even when the reverse rotation roller wears out. It is about providing.

[Means for Solving the Problems 1] The paper feeding device of the present invention has a normal rotation roller that conveys the paper to be sent out, and a support shaft arranged parallel to the rotation axis of the normal rotation roller, and has a rotation axis centered on the support shaft. a reversing roller rotatably held by the oscillating member and in contact with the 11-rolling roller to which a constant torque is applied in a direction opposite to the conveying direction of the paper; In a paper feeding device including a biasing member having one end locked to a swinging member and biasing the reverse rotation roller toward the normal rotation roller, the biasing member serves as a biasing point for the swinging member. It is characterized in that the angle of intersection of the biasing direction with the straight line connecting the center of the support shaft is arranged in the range of 40'' to 80 degrees.

[Operation] The magnitude of the contact pressure of the reverse rotation roller with respect to the forward rotation roller is determined by the magnitude of the moment of force acting on the support shaft of the swinging member.

In the paper feeding device of the present invention, as the biasing force of the biasing member decreases due to wear of the reverse rotation roller, the effective moment radius increases. As a result, the moment of force acting on the support shaft of the swinging member is kept substantially constant, and the contact pressure of the reverse rotation roller with respect to the forward rotation roller is kept substantially constant.

[Example] Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

(First Embodiment) FIG. 1 is a side view of a paper feeding device of this embodiment provided in a paper feeding cassette for a copying machine. As shown in FIG. 1, the paper feeding device of this embodiment includes a feed roller 1, a normal rotation roller 2
The main components are a swinging member 3, a reversing roller 4, and a biasing member 5.

By rotating in the direction of arrow a, the feed roller 1 picks up the topmost sheet P'f! of the many sheets P stacked in the paper feed cassette 6! -It is something that is sent out.

This feed roller 1 has a pair of levers 7 at both ends thereof.
It is rotatably supported on one end of the roller 2, and interlocks with the normal rotation roller 2 via a belt (not shown) stretched between the normal rotation roller 2 and the rotation roller 2, which will be described later.

The normal rotation roller 2 is driven by a drive motor (not shown) and rotates in the direction indicated by the arrow, thereby transporting the paper P sent out by the delivery roller 1 to the transport path 8. The normal rotation port 52 is arranged at a position where its -[• end is close to the tip of the feed guide 60 of the paper feed cassette 6.

The rotation shaft of the single roller 2 is rotatably supported by the other end of the pair of levers 7, and is also supported by a main body frame (not shown).

The swinging member 3 has a support shaft 3 whose both ends are supported on the main body frame.
0 and a pair of swinging levers 3 with one end fixed to a support shaft 30.
Consists of 1. The support shaft 30 is disposed parallel to the rotation axis of the normal rotation roller 2, and the other end of the swing lever 31 is partially movable in the vertical direction about the support shaft 30.

The rotating shaft of the reverse roller 4 is rotatably supported by the other end of the pair of swing levers 31, and the upper side of the outer peripheral surface of the reverse roller 4 is placed in contact with the lower side of the forward rotation roller 2. has been done. This reversing roller 4 is driven by a drive motor (not shown)
The rotation roller 2 is driven to rotate in the direction of arrow C, which is the opposite direction to the rotation of the normal rotation roller 2. On the shaft portion of the reverse rotation roller 4, a number 1 to a limiter (not shown) is provided, and when the number of sheets of paper P conveyed by the forward rotation roller 2 is one, it is driven by the forward rotation roller 2. In the case of two or more sheets, the drive direction is set to rotate in the driving direction (arrow C direction).

The biasing member 5 is made up of an elastic member 50 that can be expanded and contracted in one direction, and a compression spring 52 that is compressed and attached in the direction in which the elastic member 50 contracts. The telescopic member 50 has an upper end that is connected to the swing lever 3.
The lower end is fixed at a predetermined position (point of action) C at approximately the center of the main body frame (not shown).
(Point of action) Locked to B. As a result, the elastic member 50 has a straight line I that connects the positions (points of action) B and C where both ends of the elastic member 50 are locked. The reversing roller 4, which is recessed in the other end of the swing lever 31, is always urged against the forward rotating roller 2 by the expansion action of the compression spring 52. This biasing member 5 is a telescopic member 50
The position C where the upper end is locked (point of action) and the swing lever 31
The biasing direction (
They are arranged so that the intersection angle θ of the straight line 1 (in one direction) is 40″ to 80°.

The paper feeding device of this embodiment is configured as shown above.
Next, its effect will be explained.

First, when the driving motor is turned on and the normal rotation roller 2 and the feed-out roller 1 rotate, the uppermost sheet P that is in contact with the feed-out roller 1 is fed out from the paper feed cassette 6 by the seventh sheet. The fed paper P is guided by the feeding guide 60 and fed between the forward rotation roller 2 and the reverse rotation roller 4, and is conveyed to the conveyance path 8 by the rotational force of the forward rotation roller 2.

The reverse rotation roller 4 rotates in the direction of arrow d following the movement of the normal rotation roller 2 and the rotation MP due to the action of the torque limiter. Note that when two or more sheets overlap and are sent out from the paper feed cassette 6, the torque limiter causes the reversing roller 4 to run out of use (R< The second and subsequent sheets of paper are pushed back and separated, and only one sheet of paper P that is in contact with the normal rotation O-roller 2 is conveyed.

When the sheets P are sequentially fed out from the sheet feed cassette 6 in this manner, the diameter of the reversing roller 4 gradually decreases due to wear. Accompanying this, the swing lever 31 gradually moves upward by 1 degree around the support shaft 30, so that the elastic member 50 is expanded by the biasing force of the compression spring 52, and at the same time, the biasing force of the compression spring 52 gradually increases. becomes smaller. However, the biasing direction of the biasing member 5 is 40° to 8° with respect to the direct IQR.
Since it is arranged at an angle of 0°, there is a
The pressing force of the reversing roller 4 is kept substantially constant.

The changes at this time will be explained using the moment diagram shown in FIG. Here, the initial biasing force of the biasing member 5 is F, the center of the support shaft 30 is the point of action of the biasing member 5 on the A1 main body 7 lem, and the point of action of the biasing member 5 on the swing lever 31 is C
9, the distance between 80 of the biasing member 5, and the distance between A0 and R.
O1 effective moment and a half (\ is R (R = Ro-sin θ),
Let θ be the intersection angle between the direction of the biasing force F and the 100-line fork.

The moment hM acting around the center A of the support shaft 30 at the initial stage is given by: M=F−R=F−Ro−sinθ. As the reversing roller 4 wears out, the swinging lever 31 swings around 8, and the point of action C moves to, for example, C+. At this time, the moment M1 acting around A is Ml-F+ ・R+=F+
-Ro -Sfn θ. Here, F＞
F +, but sinθgusinθ1 due to θku01
becomes. Hit, point of action C moves to 01 Surt, B C+
The distance 11ffD + Ka[) becomes longer, the biasing force F decreases, and the distance of effective moment]・radius R1 becomes longer than R.

As a result, the effective moment radius R
This is compensated for by the increase in +. Therefore, by appropriately setting the intersection angle θ, spring characteristics, etc., M=F−Ro−8
inθ′:F+・Ro−sinθ. That is, the pressing force of the reverse rotation roller 4 with respect to the forward rotation roller 2 can be kept substantially constant.

In addition, if the initial value of 6Q is determined at θ2=90' as in the conventional case, as shown in Fig. 6, t acting around Δ
- Ment M2 is M2=F2 ・R2=Fz ・Ro ・5in90'=
F2・R.

is given by Therefore, when the point C2 moves to Ca, for example, due to wear of the reversing roller, the moment M3 acting around A is M3=F3 ・R3=F3-Ro lS ! If nθ3. Here, F2>F3.90°>θ3.1>si
Due to nθ3, M2>M3 always holds true.

That is, the contact pressure of the reverse rotation roller with respect to the forward rotation roller continues to decrease.

As described above, in the paper feeding device of the present embodiment, one end of the telescoping member 50 connects the biasing point C to the swinging lever 31, which is locked, and the center A of the pivot of the swinging lever 31. Since the biasing member 5 is arranged at J such that the intersection angle of the biasing direction with respect to the straight line λ is 40' to 80°, the 0-ra diameter decreases as the reversing roller 4 wears. Even when the rotation speed is increased, the contact pressure of the reverse rotation roller 4 with respect to the forward rotation roller 2 can be kept substantially constant without decreasing.

(Step regular example of intersection angle θ) For example, when using a small diameter roller with a diameter of 16 mm as the reverse rotation roller and setting the contact pressure to the forward rotation roller at 25 g/mm, considering spring variations, assembly accuracy, etc. The allowable range of the pressure setting value is ±2g. In this sense, it is necessary to suppress the low F of the contact pressure to 0.5 to 7 (approximately 2 to 3% of the initial setting value) or less for durability. Furthermore, due to durability, the maximum allowable range of change in the intersection angle θ due to wear of the reversing roller is set to 30 or less.

In Figure 3, the intersection angle θ is 10° to 100'l! 3 is a graph showing the relationship between the change in the contact pressure moment and the change in the intersection angle θ at each set intersection angle θ when the intersection angle θ is set as follows. This graph shows the effect of the biasing member on the swinging member hl B
The distance #IRo between and the center A of the support shaft is 25mm, the natural f2P of the spring member is 3Qmm, and the compression (or tension) of the spring member
When the stroke Q is set to 151, that is, Ro:
This is under conditions where the ratio of P:Q=5:6:3.

Applying the above setting conditions of a change of 3% or less in the contact pressure moment and a change of 3% or less in the intersection angle θ to this graph, the range t required for the initial setting value of the intersection angle θ is 50° to 50°.
It becomes 55°.

Note that even if the diameter of the reversing roller is large, the purpose can be achieved under all conditions by setting the intersection angle 0 in the range of 40° to 80'.

(Second Embodiment) FIG. 4 is a side view of essential parts of a paper feeding device according to this embodiment. As shown in FIG. 4, the paper feeding device of this embodiment uses a tension spring 15 as a biasing member. In this case, the swinging member 13 is connected to a support shaft 130 whose both ends are supported on a main body frame (not shown), and a pair of 1-shift levers 131 having a corner portion fixed to the support shaft 130. Become. A reversing roller 14 is rotatably supported on one end of the swing lever 131, and one end of a tension spring 15 is engaged with the other end. This tension spring 15 has an intersection angle θ of 400 where the biasing direction F4 of the tension spring 15 intersects with the straight line 4 connecting its ultimate locking position Ca and the center Δ4 of the support shaft 130. The other end is locked to the main body frame 18 so that the angle is 80'. As a result, the reverse rotation roller 14 is pressed against the normal rotation [1-512].

Also in the paper feeding device of this embodiment, the acting force of the tension spring 15 is similar to that of the compression spring of the first embodiment, and the contact pressure of the reverse rotation roller 14 with respect to the forward rotation roller 12 can be kept approximately constant. .

[Effects of the Invention] The biasing member according to the paper feeding device of the present invention has an intersection angle of the biasing direction with respect to a straight line connecting the biasing point of the swinging member and the center of the pivot of the swinging member from 40' to 80'. ' is located within the range. As a result, even if the reverse rotation roller wears out, the effective moment radius increases as the biasing force of the biasing member decreases, so the contact pressure of the reverse rotation roller against the forward rotation roller remains approximately constant. can be kept.

[Brief explanation of the drawing]

1 to 4 relate to embodiments of the present invention, and FIG.
FIG. 2 is an explanatory diagram showing changes in moment; FIG. 3 is a graph showing the relationship between changes in contact pressure [-ment] and changes in intersection angle θ; The figure is the second
FIG. 2 is a side view showing main parts of a paper feeding device in an actual IM example. 5 and 6 relate to a conventional paper feeding device, FIG. 5 is a side view of the paper feeding device, and FIG. 6 is an explanatory diagram showing changes in the moment. 2... Forward rotation roller 4... Reverse rotation l2 J-ra 30... Support shaft C... Force application point

Claims (1)

[Claims] (1) A normal roller that conveys the paper to be sent out, a swinging member that has a spindle arranged parallel to the rotation axis of the normal roller and swings about the spindle, and a swinging member that swings around the spindle. A reversing roller is held rotatably and is in contact with the normal rotating roller, and is applied with a constant torque in a direction opposite to the conveying direction of the paper. In a sheet feeding device including a biasing member that biases a rolling roller, the biasing member has an intersection angle of a biasing direction with a straight line connecting a point of biasing the swinging member and the center of the spindle. A paper feeding device characterized in that the angles are arranged in a range of 40° to 80°.