JPH0422817B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a paper sheet feeding device applied to, for example, an optical character reading device, various types of printer/copying machines, etc. Ream weight K (Kg)
The present invention relates to a sheet feeding device that stabilizes the separating and conveying function even for thin sheets of paper weighing less than 55 kg. here,
The ream weight K (Kg) of paper sheets is the size 788mm x 1091mm.
It is defined by the weight when 1000 sheets of paper are piled up, and 55Kg paper is paper whose weight is 55Kgf. This definition will be used hereinafter in this specification.

[Conventional technology]

In recent years, there has been a strong call for streamlining office work, and various office automation devices have been developed. Most of the office work involves processing various forms,
This involves creating necessary documents, but in order to streamline this kind of work, it is necessary to read the information written on the paper accurately, and to be responsible for input and output such as printing and outputting the calculation results. It is important to improve the performance of these parts. For example, optical character reading devices and various printers play an extremely important role as input/output devices for office work. on the other hand,
In this type of work, paper is often used to store and transfer information, and in reality, the amount of paper used in offices continues to increase year by year.
Under these circumstances, there is an extremely high demand for thinner forms in order to save resources and storage space. However, the automatic paper feeder that has been developed and used in the past,
Only thick forms of 55Kg paper or more are allowed to be used. This is because as the paper becomes thinner, its rigidity decreases, making it difficult to handle, causing frequent double feeds and jams, and making it impossible to achieve the original purpose of streamlining office work.

For example, optical character reading devices use relatively thick and highly rigid paper weighing 70 to 135 kg.

On the other hand, as methods for separating and conveying sheets stacked and stored in a hopper one by one, methods that utilize vacuum suction force and methods that utilize frictional force have been put into practical use.

As an example of a conventional friction-type separation mechanism, the
There is No. 4149. That is, as shown in FIG. 9, the top sheet 1 of the sheets 1 stacked on the push plate A
A pick-up roller R ₀ is lightly abutted against the pick-up roller R 0 , and the paper sheets 1 fed out by the pick-up roller R ₀ are separated by a separating member, that is, a pair of rollers disposed downstream of the pick-up roller R ₀ .
It is separated one by one by R ₁ R ₂ .

[Problem to be solved by the invention]

However, when trying to apply the conventional technology to thin paper, the following problems arise.

In a method in which paper sheets are sucked and adsorbed using a vacuum generator, since the paper is thin, air passes through it and the second and subsequent sheets of paper are adsorbed, creating a double feed.
There is also a method of applying suction to paper sheets using negative pressure to separate them, but this requires larger equipment such as air blowers, and
Moreover, the air noise is large, and the requirements for small size and low noise cannot be met.

On the other hand, if we look at the friction-type separation mechanism, which has been widely used in copiers and other applications,
Problems such as jamming, folding, and wrinkles occur due to the lack of rigidity of paper sheets.

The first paper sheet 1-a is fed out toward the feed roller _R1 by the pick-up roller _R0 as shown in FIG. A problem as shown in FIG. 10 occurs.

That is, the feed roller R ₁ is rotating clockwise as shown in FIG. 9, but the friction member R ₂ that is in pressure contact with it stops or rotates in the opposite direction, and feeds the incoming paper sheet 1 one by one. Try to separate it into parts.

Therefore, the paper sheet 1-a fed out to the left in the figure by the pick-up roller _R0 moves while sliding on the surface of the guide member G, but its tip touches the friction member _R2 . Contact will impede its progress. At this time, if the paper sheet 1 is thick and has high rigidity, the leading edge of the first paper sheet 1-a overcomes the frictional force with the friction member _R2 and moves to the left, but the thin paper sheet 1-a moves to the left. If the rigidity is low, as shown in FIG. 9, the leading edge of the paper sheet 1-a will be stopped by the frictional force of the frictional member _R2 . In other words, the first paper sheet 1-a is in a buckled state as shown in the figure.
As the pick-up roller R ₀ continues to rotate, only the rear part of the first sheet 1-a is fed out.
Finally, feed roller _R1 and pick-up roller
The first paper sheet 1-a is bent between R ₀ and
This will cause a jam. Furthermore, if the first paper sheet 1-a is bent or jammed as described above, the pick-up roller R and the second paper sheet 1-b will come into contact with each other, causing the two The feeding force acts on the paper sheets 1-b, causing jams to occur one after another.

Furthermore, since a frictional force acts on the second sheet 1-b with the first sheet 1-a, the second sheet 1-b also begins to move to the left. , the guiding effect of the first sheet 1-a against the second sheet 1-b is lost, and the second sheet 1-b buckles in the same way as the first sheet 1-a. It makes Jiyam even more intense.

Next, FIG. 10 shows a state in which the first paper sheet ₁ - _a can avoid the state shown in FIG. Indicated. In this state, the first paper sheet 1-a remains flat without being bent between the rollers R ₀ and R ₁ as shown in the figure. On the other hand, a conveying force due to friction with the first sheet 1-a acts on the second sheet 1-b, but the leading edge of the second sheet 1-b
The paper sheet 1-a is caught between the lower surface of the sheet 1-a and the friction member 6 and cannot be moved. As a result, 2
As shown in FIG. 10, the first paper sheet 1-b is deformed on the lower surface of the first paper sheet 1-a.
It may buckle and eventually break near its tip, resulting in a jam. A similar phenomenon may also occur for the third sheet 1-c.

The above has described an example in which paper sheets are separated and conveyed one by one, but in printers and the like, it is necessary to use multiple sheets made of carbon paper, non-carbon paper, or the like. In this case, it is necessary to feed a plurality of stacked paper sheets, for example, with only their leading edges glued together. This type of paper uses thin paper of about 35 kg paper.
As a result, when the topmost multi-sheet sheet is sent out by the feed roller, the second and subsequent sheets do not move due to the frictional force with the multi-sheet sheet below, and the first sheet of the multi-sheet sheet Only paper sheets are sent out. For this reason, a situation similar to that shown in FIG. 9 occurs, resulting in a jam.

All of the phenomena described above are caused by the fact that paper sheets are thin and have low rigidity, making them easy to buckle.

An object of the present invention is to provide a highly reliable sheet feeding layer that can transport thin paper of 55 kg or less to a post-processing process while avoiding folding or jamming. Another object of the present invention is to provide a paper sheet feeding device that prevents the occurrence of the skew phenomenon of thin paper of 55 kg or less.

[Means to solve the problem]

The paper sheet feeding device of the present invention includes a feeding means for applying a feeding force P (gf) to the paper sheets, and a separating means for applying resistance to the fed paper sheets, ) In order to prevent the sheets from buckling, the position where the feeding means applies a feeding force to the sheets and the position where the separating means applies a separating force to the sheets are determined in the sheet transport direction. The distance L (mm) satisfies the following formula.

L<0.83K ^3/2 /√ In addition, the paper sheet feeding device of the present invention includes a feeding means composed of a plurality of feeding members, and a feeding means, in order to prevent paper sheets from folding or skewing. and a separation means facing the.

[Effect]

The paper sheets fed out by the plurality of pick-up rollers 4 are sent between the feed roller 5 of the separation means and the friction member 6 without being subjected to rotational moment and without buckling. The distance L between the separating position of the separating means and the position applying the feeding force of the pick-up roller 4 and the feeding force P are within a predetermined range, and since the separating means is disposed facing the pick-up roller 4, the pick-up roller 4 can The fed paper sheets are accurately separated and conveyed one by one.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the paper sheet feeding device of the present invention will be described below with reference to the drawings. FIG. 1 shows the overall configuration of an embodiment of the paper sheet feeding device of the present invention.

Paper sheets 1 are stacked on a push plate 3 provided on a frame via a spring 2. The uppermost paper sheet 1-a of the stacked paper sheets is lightly abutted on a pick-up roller 4 (described later), and the pick-up roller 4 (in this embodiment) serves as a plurality of feeding members constituting a feeding means. a plurality of feed rollers 5 (two in this embodiment) and a friction member 6) constituting a separating means and arranged opposite to the pick-up roller 4;
paper sheets) are separated into individual paper sheets. The aforementioned pick-up roller 4 and feed roller 5
The motor 7 is connected via belts 9 and 11,
Further, a motor 8 is connected to the conveyor rollers 12, 12' via a belt 10, and these rollers 4, 5, 12'
are rotated by motors 7 and 8 in the same direction to carry out the sheet 1-a.

Now, when the motor 7 is driven, the plurality of pick-up rollers 4 and feed rollers 5 work together to send out the uppermost paper sheet 1-a. The paper sheet that is moved to the left in the figure by the frictional force between the friction member 6 which is pressed against the feed roller 5 via the spring 13 and the feed roller 5 comes into contact with the friction member 6. is stopped, and only the top paper sheet 1-a that comes into contact with the pick-up roller 4 and the feed roller 5 is
It is transported downstream. As a result, the stacked paper sheets 1 are separated one by one, and the conveyance roller 1
2 and 12' and sent out rearward.

The shaft 14 of the pick-up roller 4 and the feed roller 5
is connected to the shaft 15 by a transmission means such as a belt 11, and the first paper sheet 1-a is connected to the conveying roller 1.
2, 12', clutch 16 is activated to remove the drive force on shafts 14 and 15.
are attached between these shafts 14, 15 and the motor 7.

A guide member 17 is provided to guide the sheets stacked on the push plate 3, and the friction member 6 protrudes from the guide member 17 and is pressed against the feed roller 5.

FIG. 2 shows a main part of an embodiment of the paper sheet feeding device of the present invention.

The contact position 18 between the pick-up roller 4 and the paper sheet 1, that is, the position that applies a feeding force to the first sheet 1-a, and the contact position 19, that is, the contact position between the feed roller 5 and the friction member 6 located downstream thereof, The distance L from the position where a separating force is applied to the paper sheets fed out by the pick-up roller 4 is set to a length that does not cause buckling of the paper sheets between the pick-up roller 4 and the separating means during conveyance. There is.

As a result of intensive studies by the present inventor, when using thin paper sheets of 55 kg or less, the L dimension or Feeding force P (gf) for paper sheets
It has been found that it is necessary to set the distance L (mm) between the position where force is applied and the position where separation force is applied to the fed paper sheets within the range shown by the following equation (1).

L<0.83K ^3/2 /√...(1) The function will be explained below.

Euler's formula for buckling of long columns is well known as a simple theoretical formula for elucidating the buckling phenomenon.According to this, the buckling load Pk is calculated by the longitudinal elastic modulus E of the column, the second moment of area I , using length L,
It is expressed as equation (2).

P _K =nπ ² EI/L ² (2) where n is a constant determined by the support conditions at both ends of the column. Equation (2) is applied analogously to the buckling phenomenon of thin paper. If the width of the paper is b and the thickness is h, then I=
Assume that bh ³ /12 and that h is proportional to the ream weight K of the paper. In addition, the buckling load P _K is divided into the paper sheet feeding force P when the paper sheet buckles, and the length L of the column is divided into the position where the feeding force is applied to the paper sheet and the paper sheet that is fed out. Replace it with the distance L from the position where force is applied. As a result, P∝K ³ /L ² ...(3), which can be expressed as L<AK ^3/2 /√ ...(4). Here, A is a constant that can be determined experimentally. Suyuwachi (P,
If one combination of K, L) is determined by experiment, the value of the constant A is determined.

FIG. 3 shows an experimental method for investigating the vacillation properties of paper sheets. Apply force to a position L from the tip of a paper sheet having a specific ream weight K to cause the paper sheet to buckle from the state shown by the solid line to the state shown by the broken line, and measure the reaction force P when buckling. .

FIG. 4 shows the measurement results of the buckling characteristics when the ream weight K of paper sheets is 55 kg, with the horizontal axis representing the distance L and the vertical axis representing the buckling reaction force P.

Applying this result to the separation mechanism shown in Fig. 2, it is possible to reduce the pressing force that presses the paper sheet 1 against the pick-up roller 4, and to reduce the distance L between the pick-up roller 4 and the feed roller 5, in other words, the paper sheet It can be seen that it is necessary to reduce the distance L between the position 18 that applies a feeding force to the paper sheet and the position 19 that applies a separating force to the fed paper sheet.

Returning to Figure 4, the distance L can be made infinite by reducing the force by which the roller feeds out the paper sheets, but in reality, the accumulated paper sheets are separated by the frictional force P _P between the sheets. In order to feed out the paper sheet by overcoming the sum of the frictional force R acting on the tip of the paper sheet by the friction member 6, a force P _F greater than a certain level is required. (P _P > P _F +R) The frictional force P _P between the paper sheets mentioned above is the thickness of the paper sheets,
Although it varies depending on the size, the weight ω of an A2-sized paper sheet of 55 kg is approximately 16 gf, and the friction coefficient μ between the pick-up roller 4 and the paper sheet is approximately 1.0, so P _P = ω× μ=16 gf.

On the other hand, the paper sheet fed out by the pick-up roller 4 moves while sliding on the surface of the guide member 17, but when it comes into contact with the friction member 6, a frictional force R is applied to prevent the sheet from advancing. act.

If this frictional force R is not made smaller than the buckling reaction force of the sheet, jamming will occur.

This frictional force R is greatly influenced by the plunge angle at which the sheet comes into contact with the frictional member 6 and the friction coefficient (0.6 to 1.2) of the frictional member 6.

This plunge angle is determined by the dimensions and shapes of the guide member 17 and the friction member 6, but in reality, deformation such as folding of the paper sheet affects the plunge angle.

From many experiments and experiences of the present inventor, it has been found that it is best to set the maximum frictional force R to about 30 gf when the paper sheet to be handled is 55 kg paper.

Therefore, the paper sheet feeding force P _F by the roller
is 46 gf, and there is a lower limit value of the buckling reaction force P corresponding to this feeding force P _F.

That is, according to FIG. 4, if the lower limit value P ₁ of the buckling reaction force P is 46 gf, the value of the distance L corresponds to 46 gf.
L ₁ is determined to be approximately 50mm.

In principle, if the buckling reaction force P ₁ is small, the length
L ₁ (in terms of related dimensions on the paper sheet separation mechanism, the second
(L dimension in the figure) can be made larger.

Furthermore, returning to FIG. 2, pick up roller 4
A position 18 where conveying force is applied to the paper sheet 1 by
If L is the distance from the position 19 where the feed roller 5 and the friction member 6 are in contact and the separation force is applied, then the fourth
From the relationship of the buckling characteristics of paper sheets shown in the figure, this L
It can be seen that the larger the value of , the more likely paper jams and folds occur due to buckling of paper sheets.

Now, considering the above-described L dimension determined, the maximum allowable force W for pressing the paper sheet 1 against the pick-up roller 4 is determined.

Now, if the force (pressing force) for pressing the paper sheet 1 against the pick-up roller 4 is W, and the coefficient of friction between the paper sheets is μ _P , then the paper sheet 1 is stably pinched by the feed roller 5,
By the first paper sheet 1-a being conveyed,
A conveyance force is applied to the second paper sheet 1-b located below it by the frictional force between the two sheets. At this time,
Since the lower surface of the second paper sheet 1-b contacts the paper sheet 1-c below it, a frictional force is generated that opposes the above-mentioned conveying force. If the frictional force between the sheets is always the same, the second sheet 1-b will move easily, but
The front and back surfaces of paper sheets have different surface treatments, so the coefficient of friction is different, and there are air spaces, folds, wrinkles, etc. between the sheets, so the first sheet 1 -The second sheet of paper 1- due to the movement of a.
b also moves. Here, the second paper leaf 1
−b is the actual frictional conveyance force F _P (≒μ _P W)
Then, as is clear from the buckling property in Figure 4,
If the condition of P>F _P is not satisfied, bending or jamming will occur.

If the pressing force W is reduced, the frictional conveying force F _P becomes smaller, and the condition of P>F _P can be satisfied. However, in terms of design, there is a lower limit to the value of the L dimension that can be realized. Furthermore, considering that the spring 2 for pressing the paper sheet 1 against the pick-up roller 4 also has variations in characteristics, the pressing force W cannot be set close to zero, and as a result, the friction conveying force F _P
There is a minimum value for

Once the allowable friction conveying force F _P is determined from the characteristics of the paper sheets, the friction coefficient μ _P between the paper sheets and W=
The permissible value of the pressing force can be determined from the relationship F _P /μ _P.

Figure 5 focuses on the buckling characteristics of 55Kg paper sheets, thicker papers such as 72Kg paper, 110Kg paper, and thinner papers such as 48Kg paper, 35Kg paper, 25Kg paper, etc.
This shows an experimental example of the buckling characteristics of Kg paper.The horizontal axis is the distance L between the position where the pick-up roller applies a feeding force to the paper sheets and the position where the separating means applies a separating force to the paper sheets. The vertical axis shows the frictional conveying force F _P between paper sheets when buckling begins, that is, the buckling reaction force P. Curves a, b, c, d in the figure,
e and f are 25Kg paper, 35Kg paper, 48Kg paper, and 55Kg respectively
It shows the buckling characteristics of paper, 75Kg paper, and 110Kg paper.

Figure 6 shows the practical minimum friction conveying force (approximately 50gf)
The buckling characteristics of paper sheets are displayed using the buckling reaction force P, which has a value close to , as a parameter, and the horizontal axis is the ream weight K of thin paper sheets, and the vertical axis is the buckling distance L.

Curves g, h, i, and j each represent the buckling reaction force P when the value of the constant A in equation (4) above is 0.83.
The buckling characteristics of 25af, 50af, 100af, and 150af paper sheets are shown.

FIG. 7 is a diagram similar to FIG. 6, with the horizontal axis representing the buckling reaction force P and the vertical axis representing the buckling distance L, using the ream weight K of thin paper sheets as a parameter. Curves k, l, m,
When the value of constant A in equation (4) above is 0.83, n is the ream weight K of paper sheets of 25Kg, 35Kg, 48Kg, respectively.
It shows the buckling characteristics of a 55Kg paper sheet. Figure 6,
As can be clearly seen from Figure 7, the empirical formula L=0.83K ^3/2 /√...(5) very well realizes the buckling characteristics of thin paper sheets, and for specific K and P, On the other hand, it can be seen that if the distance L is set to satisfy L<0.83K ^3/2 /√...(6), the paper sheets are conveyed without buckling.

Next, the arrangement of the pick-up roller 4 and the separating means will be described. The paper sheet feeding device of the present invention has a plurality of pick up rollers 4 for conveying thin paper sheets. That is, the embodiment shown in FIG. 1 has two pick-up rollers 4.
The pick-up rollers 4 are spaced apart in a direction perpendicular to the sheet conveyance direction. If these pick-up rollers 4 are arranged symmetrically with respect to the center line in the sheet conveyance direction, they will be more effective in conveying the paper sheets in a straight line.

FIG. 8 shows the arrangement of the pick-up roller 4 of the embodiment shown in FIG. 1, and the feed roller 5 and friction member 6 that constitute the separating means. A feed roller 5 and a friction member 6 constituting the separating means are arranged to face the two pick-up rollers 4. With this configuration, the thin paper sheets 1 are restrained by the pick-up roller 4 at two places and separated at two places, so when the paper sheets 1 are conveyed, the paper sheets 1 are held by the friction member 6. The leading edge is less likely to break in the vicinity, and rotational moment is less likely to be generated on the paper sheets due to the relationship between the frictional resistance force between the paper sheets and the conveying force, and the skew phenomenon is less likely to occur in the unfed paper sheets. This effect becomes more pronounced as paper sheets become thinner.

In addition, although the above description was made using a friction roller as the feeding roller, it goes without saying that a vacuum suction means may also be used.

〔Effect of the invention〕

According to the present invention, it is possible to accurately separate and transport thin paper sheets one by one while avoiding folding and jamming of the paper sheets. As a result, OCR
It has become possible to use thin forms and paper sheets weighing less than 55 kg, which was previously difficult, in various office automation terminal devices such as computers and printers, saving paper resources and significantly reducing paper costs for users. It can produce extremely large social effects, such as reducing the amount of paper used and saving space for storing paper sheets.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing the overall configuration of an embodiment of the paper sheet feeding device of the present invention, FIG. 2 is a vertical sectional view of essential parts of an example of the paper sheet feeding device of the present invention, and FIG. 3 Figure 4 shows the method for measuring the buckling characteristics of paper sheets, Figure 4 shows the buckling characteristics of paper sheets with a ream weight of 55 kg, and Figure 5 shows the buckling characteristics of paper sheets with various ream weights. Figure 6 shows the buckling characteristics of paper sheets using buckling reaction force P as a parameter, and Figure 7 shows the buckling characteristics of paper sheets using ream K as a parameter. 8 is a diagram showing the arrangement of the pick-up roller and separation means in the embodiment shown in FIG. 1, and FIGS. 9 and 10 illustrate the conveyance state of paper sheets in a conventional paper sheet feeding device. This is a diagram. 1... Paper leaves, 4... Pick-up roller, 5
...Feed roller, 6...Friction member, 7,8...Motor, 9,10,11...Belt, 12,12'
...Conveyance roller.

Claims (1)

[Scope of Claims] 1. In a paper sheet feeding device that separates and conveys paper sheets of 55 kg or less stacked and stored on a push plate one by one, the first paper sheet on the push plate. Feeding force P
(gf), and a paper sheet fed out by the feeding means.
a separating means for separating and feeding paper sheets one by one, the feeding means having a plurality of feeding members spaced apart from each other in a direction perpendicular to the sheet conveying direction, and the separating means A plurality of feed rollers and separation members are arranged to face each other, and the transport direction is between a position where the feeding means applies a feeding force to the paper sheets and a position where the separation means applies a separating force to the paper sheets. A paper sheet feeding device characterized in that a distance L (mm) of is set within the following range so that buckling of the paper sheet does not occur between the feeding means and the separating means. L<0.83K ^3/2 /√ Here, K is the ream weight (Kg) of paper sheets, and is defined as the weight when 1000 sheets of paper with a size of 788 mm x 1091 mm are piled up.