JPH11227954A - Sheet material feeding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To cause optimum and stable pressing force to act on sheet material. SOLUTION: This device is provided with a pressing weight member 14 to be rested over loaded and disposed sheet material 11, a guide means 5 guiding the pressing weight member 14 to the vertical direction, a swing arm 16 which is pivoted to the pressing weight member 14 at its one end in such a way that it can be rocked within a vertical surface, and is provided with a balancing weight member 17 at the other end, and with a holding means 18 which supports the swing arm 16 in such a way that the component force of the balancing weight member 17 is added to the pressing force of the pressing weight member 14, and also that the component force will be increased as the pressing weight member 14 is lowered down.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bottom feed type sheet material feeding apparatus for sequentially feeding stacked sheet materials from below, and more particularly to an improvement in means for pressing the sheet materials.

[0002]

2. Description of the Related Art In a conventional sheet material supply apparatus of this kind used for a copying machine or the like, a stacked sheet material is pressed from above by a sheet pressing member 1 as shown in FIG.

The sheet holding member 1 is provided with pins 2 slidable in the left and right directions at the left end and the right end, respectively. One of the pins 2 is provided with one end of a swing arm 3 and a rebound spring 4, and the other is provided with the other. One end of another swing arm 3 and one end of a repulsion spring 4 are pivotally connected to the pin 2.

The other end of one swing arm 3 and the other end of the repulsion spring A are pivotally connected to support points P1 and P2 on a fixed body 4, respectively. The other end of the other swing arm 3 and the other end of the repulsion spring 4 are fixed. It is pivotally connected to supporting points P1 'and P2' on the body 4, respectively.

Since the support points P1 and P1 'and the support points P2 and P2' are provided at symmetrical positions, the swing arms 3 and the repulsion springs 4 intersect each other. I have.

The sheet pressing member 1 moves to a high position indicated by a solid line when the sheet material 5 is in a full stack state,
In the low stack state of the sheet material 5, the sheet material 5 moves to a low position indicated by a chain line.

Now, the angles formed by the swing arm 3 and the spring 4 in the full stack state and the low stack state are α1 and β1 (α1, β1> 0 °), respectively.
The angles between the swing arm 3 and the longitudinal axis of the sheet pressing member 1 are α2 and β2 (both are smaller than 90 °), the pressing force of the sheet pressing member 1 is f1 and f2, and the tension of the spring 4 is T1 and T1, respectively. Assuming T2, the following relationship is established.

F1 = T1 · sinα1 · sinα2 (a) f2 = T2 · sinβ1 · sinβ2 (b)

The angles α1 and β1 have a relationship of α1 <β1, and the angles α2 and β2 have a relationship of α2 <β2. Then, the tensions T1 and T2 of the spring 4 can be considered to be substantially equal.

Therefore, according to the above equations (a) and (b), F
A relationship of 1 <F2 is obtained, which means that the pressing force of the sheet pressing member 1 increases as the stack amount of the sheet materials 5 decreases, that is, as the stacked weight of the sheet materials 5 decreases. Suggest that.

[0011]

As apparent from the above description, the sheet pressing mechanism in the conventional sheet feeding apparatus changes the pressing force on the sheet 5 by changing the operating angle of the spring 4. Therefore, an appropriate pressing force may not be obtained due to a variation in accuracy of the spring 4, and the pressing force may fluctuate due to a secular change of the tension of the spring 4.

SUMMARY OF THE INVENTION An object of the present invention is to provide a sheet material supply apparatus capable of applying a proper and stable pressing force to a sheet material in view of such a situation.

[0013]

SUMMARY OF THE INVENTION The present invention relates to a bottom feed type sheet material feeding device for sequentially feeding stacked sheet materials from below, wherein the pressing device is mounted on the stacked sheet materials. Weight member, guide means for vertically guiding the pressing weight member, and one end pivotally connected to the pressing weight member so as to swing in a vertical plane, and a balance weight at the other end. A swing arm provided with a member, and a component force of the balance weight member is added to the pressing force of the pressing weight member, and the component force increases as the pressing weight member descends. And supporting means for supporting the swing arm.

[0014]

FIG. 1 shows an embodiment of a bottom feed type sheet material supply apparatus according to the present invention. In this sheet material supply device, a sheet material 11 such as recording paper is stacked on a sheet placement plate 10, and the lowermost sheet material 11 is fed leftward by a feed roll 12 and a retard roll 13. .

The pressing weight 14 provided in the sheet feeding device presses the stacked sheet materials 11 from above, and moves vertically while being guided by the guide holes 15a of the guide plate 15. can do.

The swing arm 16 has one end pivotally connected to the pressing weight 14 so as to be able to swing in a vertical plane, and
At the other end, a balance weight 17 is provided. Also,
The swing arm 16 has a long hole 1 along its longitudinal axis.
6a, and the long hole 16a is slidably fitted to the support pin 18.

The support pin 18 is provided at a position higher than the pressing weight 14 when the sheet material 11 is fully stacked, so that the swing arm 16 always moves obliquely upward from the pressing weight 14. Inclined in a manner.

FIG. 2 is a principle diagram for explaining the pressing action of the pressing weight 14. As shown in FIG. This FIG. 2 and the following (1)
As shown in the equation, the pressing force F applied to the sheet material 11 by the pressing weight 14 is a weight W2 of itself, a pressing force F1 based on a component force of the balance weight 17, and the balance weight 1
7 and the pressing force F2 based on the moment generated.

F = W2 + F1 + F2 (1)

Now, the weight of the balance weight 17 is W1, the inclination angle of the balance weight 17 with respect to the horizontal line is θ, the pivot point 19 of the swing arm 16 with respect to the pressing weight 14 and the vertical axis including the axis of the support pin 18. Assuming that the distance from the surface is a, the pressing forces F1 and F2 are 0 <θ <90 °
Is given by the following equations (2) and (3), respectively.

[0021] The pressing force F by the pressing weight 14 is as described in the above (1) to (4).
Based on the equation (3), it is expressed as the following equation (4).

[0022] The pressing weight 14 rises to a position shown by a solid line when a predetermined number of the sheet materials 11 are stacked, and falls to a position shown by a chain line when the number of the sheet materials 11 is zero.

Here, assuming that the stacked height of the sheet material 11 is b and the height of the support pin 18 is c, the relationship of the following equation (5) is obtained under the condition of 0 <θ <60 °.

[0024] This equation (5) is modified as follows.

[0025] As is apparent from the above equation (6), the stacking height b of the sheet material 11 and the inclination angle θ are: On the other hand, as is apparent from the equation (4), the pressing force F of the pressing weight 14 and the swing arm 1
The inclination angle θ of 6 Therefore, between the loading height b and the pressing force F, Is established.

Equation (9) indicates that the pressing force F increases as the stacking height b decreases, that is, as the stacking weight of the sheet material 11 decreases. An appropriate pressing force always acts on the material 11.

As described above, according to the sheet supply apparatus of the present invention, the pressing force that increases as the loaded weight of the sheet 11 decreases can be generated without using a spring.

In the above embodiment, the elongated hole 16a provided in the swing arm 16 is slidably fitted to the support pin 18, but as shown in FIG. The support pin 18 may be slidably fitted in the hole 21, and the swing arm 16 may be pivotally attached to the support pin 18. In this case, as indicated by the chain line, the support pin 18 moves leftward with the elevation of the pressing weight 14.

Also in this embodiment, as the inclination angle of the swing arm 16 increases, the pressing force based on the component force of the balance weight 17 increases. As the load weight decreases, the pressing force of the pressing weight 14 increases.

[0030]

According to the present invention, it is possible to obtain the function of increasing the pressing force on the sheet material as the stacked height of the sheet material decreases, without using a spring. Therefore, an appropriate and stable pressing force can be applied to the sheet material without being affected by variations in accuracy of the spring or aging.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing an embodiment of a sheet material supply device according to the present invention.

FIG. 2 is a principle diagram for explaining an operation of the sheet material supply device according to the present invention.

FIG. 3 is a conceptual diagram showing another embodiment of the sheet material supply device according to the present invention.

FIG. 4 is a conceptual diagram showing a configuration of a conventional sheet material supply device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 sheet mounting plate 11 sheet material 12 feed roll 13 retard roll 14 pressing weight 15 guide plate 14 a guide hole 16 swing arm 16 a long hole 17 balance weight 18 support pin 20 support member 21 long hole

Claims (2)

[Claims] 1. A bottom feed type sheet material feeding device for sequentially feeding stacked sheet materials from below, comprising: a pressing weight member placed on the stacked sheet materials; Guide means for guiding the weight member in the vertical direction, a swing arm having one end pivotally attached to the pressing weight member so as to be able to swing in a vertical plane, and a balance weight member attached to the other end, The swing arm is supported so that the component force of the balance weight member is added to the pressing force of the pressing weight member, and the component force increases as the pressing weight member descends. A sheet supply device, comprising: 2. The support means supports the swing arm such that the swing arm is inclined obliquely upward and swings around a support point and slides with respect to the support point. 2. The sheet material supply device according to 1.