JP2002356240A - Sheet feeding method, sheet feeding device executing this and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet feeding method, a sheet feeding device executing this and an image forming device capable of positively separating an uppermost sheet from second sheets and onward in a sheet stacked body. SOLUTION: In the feeding method, the uppermost sheet is delivered in a feeding direction by rotating a feeding roller abutted on an upper most part of stacked sheets. It is characterized by that the feeding roller is provided with a vibrating means for vibrating in the same direction as the stacked direction of the sheets, and a frequency of the vibration is provided by a value of (1/(4π))×(E/(3ρ))<(1/2)> ×(m/L1)<2> ×d composed of a modulus E of longitudinal elasticity of paper, density ρ of paper sheet, thickness D of paper sheet, a vibration parameter m which is positive value solution of a relational expression Cos(m)×Cosh(m)=-1, and a longer distance L1 of distances to a feeding roller position from end edges of the sheet perpendicular to the feeding direction on both sides of the sheet.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet feeding method in a copying machine, a facsimile, a printer, and the like, a sheet feeding apparatus for executing the method, and an image forming apparatus.

[0002]

2. Description of the Related Art Conventionally, as a feeding method of rotating a feeding roller in contact with the uppermost portion of a stacked sheet and feeding the uppermost sheet in a feeding direction, for example, a corner claw as shown in FIG. There are a separation method, a friction pad separation method as shown in FIG. 2, and a separation method as shown in FIG. However, FRR stands for Feed and Reverse Ro
ller (feed and reverse rollers). Hereinafter, problems to be solved by the invention will be described.

In the corner claw separation method shown in FIG. 1, the feed roller 1 rotates, the top sheet of the sheet 1 stacked on the tray 2 and raised by the bottom plate raising means 6 is fed in the feed direction 3. At the time of feeding, both the tip angles of the uppermost sheet of the sheet 1 abut against the separation claws 5 disposed at the both tip angles of the tray 2, and thereafter, only the uppermost sheet is fed with the separation claw 5. In this method, only the uppermost sheet is fed by bending between the rollers 4 and both the tip angles of the uppermost sheet are separated from the separation claws 5.

On the other hand, in the friction pad separation method shown in FIG. 2, when several sheets of the sheet 1 enter between the feeding roller 7 and the friction pad 8 due to the weight of the sheet 1, the uppermost sheet is removed. Because the entry position and the entry angle are different from the second and subsequent sheets, and the coefficient of friction between the sheet 1 and the feeding roller 7 and the friction pad 8 is different, only the top sheet is fed, This is a method in which the second and subsequent sheets are separated.

Further, in the FRR separation method shown in FIG. 3, the feeding roller (pickup roller) 9 is rotated, stacked on the tray 2, and the uppermost sheet of the sheet 1 raised by the bottom plate raising means 6 is fed in the feeding direction. 3, and thereafter, a feed roller (pickup roller) 9 rotates, and the uppermost sheet of the sheet 1 stacked on the tray 2 and raised by the bottom plate raising means 6 is fed in the feed direction 3. Then, the feed roller 10
Some of the sheets 1 enter between the rotation roller 11 and the reverse rotation roller 11.

[0006]

However, in the corner claw separating method, as described above, in the case of the sheet 1 in which the close contact force acts, even if the reverse rotation roller 11 is used,
The second and subsequent sheets fed together with the uppermost sheet could not be separated, so that the so-called non-feeding could occur.

Further, in the friction pad separation method, in a high humidity or static electricity environment, an adhesive force is generated between the stacked sheets 1, and the uppermost sheet and the second and subsequent sheets stick together. When feeding only the top sheet from this, the second and subsequent sheets also follow, and the top sheet and the second sheet are stuck together to make them seemingly strong, making them strong. There was a case where a so-called non-feed occurred in which no behavior was caused, and thus no sufficient bending for detaching from the separation claw 5 was achieved, and no sheet was fed.

However, even in the FRR method, as described above, in the case of the sheet 1 in which the adhesive force acts,
When the uppermost sheet is fed, the second and subsequent sheets also follow the uppermost sheet, which sometimes causes a so-called double feed.

The present invention has been made in view of the above-mentioned problems of the prior art, and has as its object to surely separate the uppermost sheet and the second and subsequent sheets in a sheet laminate. To provide a sheet feeding method, a sheet feeding apparatus and an image forming apparatus that execute the method.

[0010]

According to a first aspect of the present invention, there is provided a sheet feeding method comprising rotating a feeding roller in contact with an uppermost portion of a stacked sheet to feed the uppermost sheet in a feeding direction. In the feeding method, the feeding roller includes a vibrating means for vibrating in the same direction as the stacking direction of the sheets, and the frequency of the vibration is in a direction perpendicular to the feeding direction and The longer one of the distances from the edge of the sheet on both sides to the feed roller position is L1, the longitudinal elastic modulus of the sheet is E, the density of the sheet is ρ, the thickness of the sheet is d, and Relational expression Cos (m) x Cosh (m)
(1 / (4π)) × (E / (3ρ)) ^(1/2) ×
(M / L1) ² × d.

According to a second aspect of the present invention, during the vibration, the reciprocating rotation in which the feeding roller rotates in the opposite direction to the feeding direction is added at the same frequency as the vibration. .

According to a third aspect of the present invention, the vibration is applied immediately before the sheet is fed.

According to a fourth aspect of the present invention, in the sheet feeding method, the longer one of the distances from the edge of the sheet on both sides of the sheet to the position of the feeding roller is defined as L2. The vibration is (1 / (4π)) × (E
/ (3ρ)) ^(1/2) × (m / L1) ² × d.

According to a fifth aspect of the present invention, there is provided a sheet feeding apparatus for executing the sheet feeding method according to any one of the first to fourth aspects.

According to a sixth aspect of the present invention, in the sheet feeding apparatus, the vibration is applied immediately after sheets are provided in the sheet storage cassette.

According to a seventh aspect of the present invention, the vibration is applied immediately after power-on and immediately after use.

The sheet feeding device according to the present invention is characterized in that the vibration is applied in an environment having a humidity equal to or higher than a preset humidity by using a temperature detecting means.

According to a ninth aspect of the present invention, there is provided the sheet feeding apparatus, further comprising a user control unit for the vibration, wherein the vibration is applied when requested by a user.

An image forming apparatus according to a tenth aspect is provided with the sheet feeding device.

[0020]

[Embodiment 1] A sheet feeding method according to Embodiment 1 will be described with reference to FIGS. 4 to 7, Table 1, and FIG. FIGS. 4 to 7 show at least a method for feeding the uppermost sheet of the stacked sheets and separating the second and subsequent sheets, such as a corner claw separation method, a friction pad separation method, or an FRR separation method. FIG. 3 is a diagram for explaining an outline of the present invention for a general feeding method having one feeding roller.

According to the feeding method of this embodiment, a feeding roller 13 for feeding the uppermost sheet in the feeding direction 3 abuts on the uppermost sheet of the stacked sheets 1, and This is a feeding method characterized by applying a vibration having a frequency f shown in Expression (1) from the vibration means 12 to the feeding roller 13 in the same direction as the stacking direction of the sheets 1.

F = (1 / (4π)) × (E / (3ρ)) ^(1/2) × (m / L1) ² × d (1) In the equation (1), L1 is a feeding direction. 3 is the longer of the distances from the edges of the uppermost sheet on both sides of the uppermost sheet to the position of the feed roller 13, and E is the length of the sheet. 1 is the modulus of longitudinal elasticity, ρ is the density of the sheet 1, d is the thickness of the sheet 1, and m is the vibration parameter. The vibration parameter m is
It is determined from the positive solution of equation (2). Cos (m) × Cosh (m) = − 1 (2) In FIG. 4, however, L1 is a half distance of the width in the direction perpendicular to the feeding direction 3, in other words, in the width direction. It is shown as an example. That is, assuming that the dimension in the width direction of the sheet 1 is L, then L1 = L / 2, and the feeding roller 13 is positioned at a position where the width of the sheet 1 is halved in the width direction of the sheet 1. Contact the upper sheet. Note that, in this example, the description is made with L1 = L / 2,
It is not necessary to take this way. For example, when the feeding roller 13 is disposed at a distance L / 3 from one end side in the width direction of the sheet 1, L1 is “in a direction perpendicular to the feeding direction and on both sides of the uppermost sheet. L1 = 2L / 3 (= the longer one of the distances from the edge of the uppermost sheet to the position of the feed roller)
LL / 3). However, arranging the feeding roller 13 at an asymmetric position in the width direction of the sheet 1 in this manner may cause skew in sheet feeding, and L1 = L / 2 as much as possible. Is desirable. That is, it is best to arrange the feeding roller 13 at a half position in the width direction of the sheet 1.

Equations (1) and (2) are obvious from the boundary conditions for obtaining an analytical solution in the resonance state when the bending of the uppermost sheet is expressed by the displacement of the two-dimensional beam. Expresses an expression. Assuming that the displacement of the top sheet in the bending direction is y and the position of the sheet 1 in the width direction is x, the bending of the top sheet is represented by the differential equation of Expression (3).

ΡA (∂ ² y / ∂t ² ) + EI (∂ ⁴ y / ∂x ⁴ ) = 0 (3) where I in the equation (3) is a second moment of area, and along the feeding direction 3 Assuming that the dimension of the uppermost sheet is b, I
= A bd ^3/12. A is a cross-sectional area, and A = b
d. By substituting equation (3) with a variable-separated form such as y = u (x) × cos (nt), equation (4) is derived.

N ² ρAu = EI (d ⁴ u / dx ⁴ ) (4) where n is an order indicating a vibration mode and takes a natural number. n = 1 is the resonance state of the first mode (fundamental vibration), n
The resonance state is represented by the order n, such that = 2 is the resonance state of the second mode, n = 3 is the resonance state of the third mode, and so on. Here, m is adopted as a vibration parameter,
And, by placing the following equation (5) with respect to the equation (4),
Equation (6) is obtained with α, β, γ, and δ as constants.

M ⁴ / L1 ⁴ = n ² ρA / (EI) (5) u = α · cos (m / L1 · x) + β · sin (m / L1 · x) + γ · exp (m / L1 · x) + δ · exp (−m / L1 · x) (6) In contrast to the equation (6), as shown in FIG. By imposing the above boundary condition that the position of the edge of the uppermost sheet located at a distance L1 from the feed roller 13 as a free end of displacement, that is, as the two boundary conditions, x = 0 (feed roller 13), y = 0 and dy / dx =
0, x = L1 (the position of the edge of the uppermost sheet) d
By imposing ² y / dx ² = 0 and d ³ y / dx ³ = 0,
Equation (2) is derived, and simultaneously equation (1) is derived from equation (5).

A vibration parameter m which is a positive value solution of the equation (2)
Are n = 1 (first mode), 2 (second mode), 3
(Third mode)... In the order of m = 1.8751 and 4.6
., 947.8,. In Table 1,
The vibration parameters m up to n = 9 (ninth mode) are listed. FIG. 5 corresponds to the schematic view of the feeding method of the present invention shown in FIG. 4, in which the feeding direction 3 is viewed from the front and the back of the paper and the front is viewed from the back. Is a state viewed from the direction of the feeding direction 3 '. FIG. 5 shows the primary mode (n = 1, 1) of the uppermost sheet obtained when the vibration parameter m = 1.8751 at the same time.
Vibration of the fundamental vibration), that is, the resonance state 1 of the first mode
4 is also shown. In the case of FIG. 5, as described above, the feed roller 13 is disposed at one half of the width of the uppermost sheet in the width direction. 13 on both sides in the width direction,
And symmetrically, a first-order mode resonance state 14 occurs. However, in the present invention, the uppermost sheet in each resonance state is represented by two-color curves of black and gray throughout. FIG. 6 shows a second mode resonance state 15 in which n = 2 when the vibration parameter m = 4.6941. Also in this case, since the conditions other than the vibration parameter m are the same as those in FIG. 5, the resonance state 15 of the secondary mode is symmetrical on both sides in the width direction with the feeding roller 13 as the center. Above,
In particular, the resonance states in the first and second modes have been described. However, by changing the vibration parameter m in accordance with Table 1, other resonance states may be changed as shown in FIG.

According to the feeding method according to claim 1 having such a configuration, when the stacked sheets 1 are exposed to a high humidity or an electrostatic environment and an adhesion force is generated between the sheets 1, a conventional feeding method is used. The feeding of the uppermost sheet of the sheet 1 and the separation of the second and subsequent sheets, which have been difficult in the first embodiment, are performed by the vibrating means 12 so that the feed roller 13 is achieved with the vibration parameter m. Causes the uppermost sheet to separate from the second and subsequent sheets, thereby removing the adhesive force generated between the sheets 1, and feeding the uppermost sheet and the second sheet. Achieve subsequent sheet separation.

An embodiment of the present invention will be described in which the sheet is paper and has the following characteristic values. Density of paper: ρ = 700 [kg / m ³ ] Longitudinal modulus of paper: E = 7.00E9 [Pa] Distance: L1 = 210E−3 [m] / 2 [m] In the above example, vibration parameters When m is set to 1.8751, and the resonance mode of the first mode is performed on the uppermost sheet, the natural frequency f calculated from the equation (1) is 3.
7 [Hz]. In an environment of 80% humidity as a high humidity environment, the adhesive force acts between the above-mentioned papers, and approximately 300 gf between the uppermost sheet and the second and subsequent sheets in the feeding direction 3. ] Has been applied. At this time, when a vibration having the same frequency as the natural frequency f is applied to the feed roller 13 by the vibration means 12, a resonance state 14 of the first mode as shown in FIG. The space between the second and subsequent sheets was separated, and the uppermost sheet was fed and the second and subsequent sheets were separated. In addition, the vibration parameter m was set to 4.6941, and the resonance state of the second mode was performed on the uppermost sheet. The natural frequency f calculated from the equation (1) was 23.2 [Hz]. . In this case, a second mode resonance state 15 as shown in FIG. 6 occurs, the uppermost sheet is separated from the second and subsequent sheets, and the uppermost sheet is fed and the second sheet is fed. Subsequent separation of the sheets was made.

Table 15 shows the natural frequency when a higher-order mode resonance state is given to paper having the above characteristic values.
Has been shown.

[0031]

[Table 1]

[Embodiment 2] In this embodiment, in the feeding method in Embodiment 1, during the vibration described in Embodiment 1, the feeding roller rotates in the feeding direction and reversely in the feeding direction. A reciprocating rotation constituted as described above is added at the same frequency as the vibration frequency.

The feeding method according to the second embodiment will be described mainly with reference to FIG. 8 or the above-described drawings. As shown in FIG. 8, the feeding method according to the present embodiment is configured such that the feeding roller 13 to which vibration is applied by the vibrating means 12 is reciprocated in a feeding direction indicated by an arrow 3 and a reverse rotation opposite to the feeding direction. It has a configuration in which the rotation 16 is added at the same frequency as the frequency of the vibration by the vibration means 12.

In the feeding method according to the second embodiment having such a configuration, when the sheet laminate 1 is exposed to a high humidity or an electrostatic environment and a high adhesive force is generated between the sheets 1, the conventional feeding method is used. The feeding of the uppermost sheet 1a of the sheet laminate 1 and the separation of the second and subsequent sheets, which were difficult by the method, are performed by the vibrating means 12 causing the feeding roller 13 to vibrate as described in the first embodiment. With the parameter m, the resonance state of the uppermost sheet is achieved, the uppermost sheet is separated from the second and subsequent sheets, and the adhesion generated between the sheets 1 is thereby removed. , Reciprocating rotation 16
The uppermost sheet is translated and reciprocated in the feeding direction and in the opposite direction via the frictional force between the feeding roller 13 and the uppermost sheet. As a result, the uppermost sheet is moved between the uppermost sheet and the second and subsequent sheets. The generated adhesion force is reliably removed more than in the first embodiment,
Feeding of the top sheet and separation of the second and subsequent sheets are achieved. [Embodiment 3] A feeding method in Embodiment 3 will be described with reference to the above-described drawings. The third embodiment is characterized in that, in the feeding method according to the first or second embodiment, the vibration described in the first or second embodiment is applied immediately before sheet feeding. Is the way.

According to the feeding method of the third embodiment, the vibration is applied each time immediately before the sheet is fed, and the uppermost sheet 1a and the two sheets 1a described in the first or second embodiment are applied. The removal of the adhesion generated between the first and second sheets 1b, 1c,..., The feeding of the uppermost sheet 1a, and the separation of the second and subsequent sheets 1b, 1c,. Is done. [Embodiment 4] The feeding method in the embodiment 4 is shown in FIGS.
This will be described with reference to FIG. In the fourth embodiment, in the feeding method according to any one of the first to third embodiments, any one of the distances from the edge of the sheet on both sides of the sheet to the feeding roller in the feeding direction is longer. When the distance is L2, a vibration having a natural frequency f ′ represented by Expression (7) is added to the vibration.

F ′ = (1 / (4π)) × (E / (3ρ)) ^0.5 × (m / L2) ² × d (7) In FIG. 9, L2 is in the feeding direction indicated by arrow 3 On the other hand, it corresponds to the distance from the edge of the sheet located in the leeward direction to the feed roller 13, and has the natural frequency determined by the equation (7) together with the vibration parameter m = 1.8751. Is performed in the leeward direction in the feeding direction 3 from the feeding roller 13. In FIG. 10, the resonance state 18 of the second mode is similarly performed with the natural frequency similarly determined from Expression (7) together with the vibration parameter m = 4.6941.

Accordingly, in addition to the separation of the uppermost sheet and the second and subsequent sheets by the feeding method in the first to third embodiments, the separation in the feeding direction 3 by the feeding method in the fourth embodiment. , The peeling is performed almost entirely between the uppermost sheet 1a and the second and subsequent sheets 1b, 1c,..., Whereby the adhesive force is almost completely removed from the entire sheet. As described above, the feeding of the uppermost sheet 1a and the second and subsequent sheets 1b, 1c,.
Separation is achieved. [Embodiment 5] This embodiment 5 is a feeding apparatus provided with the feeding method according to any one of the embodiments 1 to 4. FIGS. 11 to 13 are schematic diagrams showing an example of the feeding device according to the fifth embodiment. The feeding device shown in FIG. 11 is obtained by applying the feeding method of the first embodiment to a corner claw separating device. FIG.
In the case of the feeding device shown in FIG. 1, the feeding roller 4 is provided as a feeding roller to which the vibration means 12 is provided. Feed roller 4
Applies the vibrations generated by the vibration means 12 while being in contact with the uppermost sheet of the sheets 1 stacked and housed in the tray 2 and raised by the bottom plate raising means 6.
As a result, the uppermost sheet becomes in a resonance state, peels off from the second and subsequent sheets, and at the same time, the adhesion is removed,
Using the contact of the uppermost sheet with the separation claw 5 and the deflection of the uppermost sheet, only the uppermost sheet is fed, and the second and subsequent sheets are placed inside the tray 2. Achieve separation to keep.

On the other hand, the feeding device shown in FIG.
Is applied to a friction pad separation device. In the case of the feeding device shown in FIG.
The feeding roller 7 controls the feeding roller 7 to give. The feed roller 7 applies the vibration generated by the vibration unit 12 to the uppermost sheet among several sheets entering between the feed roller 7 and the friction pad 8 among the stacked sheets 1. Give. As a result, the uppermost sheet comes into a resonance state, peels off from the second and subsequent sheets, and at the same time, the adhesive force is removed, and is determined by the entry position and the entry angle between the feed roller 7 and the friction pad 8. For feeding and separation, the top sheet is fed and the second and subsequent sheets are separated.

Further, in the feeding apparatus shown in FIG. 13, the feeding method of claim 1 is similarly applied to an FRR separating apparatus. In the case of the feeding device illustrated in FIG. 13, a feeding roller (pickup roller) 9 controls the feeding roller that imparts the vibration unit 12. Feeding roller (pickup roller) 9
Applies the vibrations generated by the vibration means 12 while being in contact with the uppermost sheet of the sheets 1 stacked and housed in the tray 2 and raised by the bottom plate raising means 6.
As a result, the uppermost sheet becomes in a resonance state, peels off from the second and subsequent sheets, and at the same time, the adhesion is removed,
Next, the paper is fed to the feeding roller 10 and the reverse rotation roller 11 to be kept down. Thereafter, the uppermost sheet and the second and subsequent sheets from which the adhesion force has been removed are fed by the feed roller 10 and the reverse rotation roller 11, and the second and subsequent sheets are separated. I do. In the example of the FRR separating apparatus, the feeding roller (pickup roller) 9 acts as the feeding roller to which the vibration means 12 is provided, but it may be provided to the feeding roller 10. Alternatively, both of them may be applied to the feeding roller. [Sixth Embodiment] A sixth embodiment is a feeding device according to the fifth embodiment, wherein the above-described vibration is applied immediately after the power of the feeding device is turned on and immediately after use standby. .

Before the power is turned on or when the apparatus is on standby, humidity, static electricity, or other additional environmental factors often act for a long time. In this case, an adhesive force is generated between the sheets. In the feeding device according to claim 6, even when the sheet is not fed, immediately after turning on the power of the feeding device, or
Immediately after use standby, by applying the above-described vibration to the sheet, the uppermost sheet is brought into a resonance state, peeled off from the second and subsequent sheets, and the adhesive force is removed at the same time. Thus, the feeding of the uppermost sheet and the separation of the second and subsequent sheets are prepared for the feeding after being left for a long time. [Seventh Embodiment] The feeding device of the seventh embodiment is characterized in that the above-described vibration is applied immediately after the sheet is provided in the feeding device in the feeding device of the fifth or sixth embodiment. A feeding device.

When stacking and storing sheets in the feeding device, there may be a case where several sheets adhere to each other due to burrs or the like of the cutting of the sheets, or adhesion between the sheets depending on the storage state of the sheets. In the feeding device according to the seventh embodiment, immediately after the sheets are stacked on the feeding device, that is, even when the sheet is not fed, for the sheets in the apparent close contact state,
Vibration is applied to the feed roller to cause the uppermost sheet to resonate, to separate the sheets, and at the same time to remove the adhesive force. This ensures that the uppermost sheet is fed and the second and subsequent sheets are separated. [Eighth Embodiment] The feeding device according to the eighth embodiment is the same as the feeding device according to any one of the fifth to seventh embodiments, except that a humidity detecting unit is provided, and in an environment where the humidity exceeds a preset humidity, the vibration described above is applied. A feeding device characterized in that the feeding device is provided.

When there is an environmental change to high humidity, a high adhesive force is gradually generated between the sheets. The feeding device according to the eighth embodiment has a humidity detecting unit for detecting humidity, and when the humidity exceeds a preset humidity threshold value, the feeding roller is not used even when feeding a sheet. Vibration is applied to bring the uppermost sheet into a resonance state, peeling between the sheets, and at the same time, removing the adhesion. This ensures that the uppermost sheet is fed and the second and subsequent sheets are separated. [Embodiment 9] The feeding device according to the eighth embodiment is the same as the feeding device according to any one of the fifth to eighth embodiments, except that the feeding device has the above-described user control means for the vibration. Is provided.

For example, art paper, coated paper, glossy paper, OH
Depending on the surface condition of the sheet, such as a P sheet, a high adhesion force may be generated even in a humidity environment of about middle humidity. In the feeding device according to the ninth aspect, the user has a user control unit for causing the user to select a sheet selected by the user and in advance apply a vibration to the sheet by himself because the user is concerned about a high adhesive force between the sheets. With respect to a sheet having various surface conditions used by the user, the uppermost sheet is brought into a resonance state, and the sheets are separated from each other, and at the same time, the adhesion is removed. This ensures that the uppermost sheet is fed and the second and subsequent sheets are separated. [Tenth Embodiment] A tenth embodiment is an image forming apparatus including any one of the feeding devices according to the fifth to ninth embodiments. FIG. 1 is a schematic diagram of an image forming apparatus according to a tenth embodiment.
It is shown in FIG. In the image forming apparatus shown in FIG. 14, the feeding device according to any one of claims 5 to 9 is replaced with the manual feeding unit 1.
9, each of which is provided in the bank feeding section 20.
In this way, the uppermost sheet is fed and the second and subsequent sheets are separated by the feeding device described in (9) to (9).

[0044]

According to the present invention, the following effects can be obtained. That is, in the feeding method of rotating the feeding roller in contact with the uppermost sheet of the stacked sheet laminate and feeding the uppermost sheet in the feeding direction, the uppermost sheet and the second and subsequent sheets are When in a high humidity or static electricity environment, an adhesive force is generated between the sheets, and as a result, the sheets adhere to each other, and seem to be united.
Although the case of "double feeding" or "non-feeding" was left as it is, by using the feeding method of claim 1, the uppermost sheet resonated, and peeled off and simultaneously adhered to the second and subsequent sheets. In order to eliminate the force, the uppermost sheet can be fed and the second and subsequent sheets can be separated.

According to the second aspect of the present invention, translation and reciprocation are performed between the uppermost sheet and the second and subsequent sheets, and the uppermost sheet and the two sheets in the feeding method according to the first aspect. The separation from the sheets after the first sheet is further performed, so that the adhesion between these sheets can be removed, the uppermost sheet can be fed, and the second and subsequent sheets can be separated.

According to the sheet feeding method of the third aspect,
Claim 1 or Claim 2 each time immediately before sheet feeding.
As described in the above feeding method, it is possible to remove the adhesion between the sheets, to feed the uppermost sheet, and to separate the second and subsequent sheets, thereby improving the reliability of the feeding and separation. .

According to the present invention as set forth in claim 4, claim 1 is as follows.
4. In addition to the separation between the uppermost sheet and the second and subsequent sheets in the feeding method according to any one of claims 1 to 3, separation between the sheets in the feeding direction is also promoted, and thus the uppermost sheet and the two sheets Almost the entire area between the sheets after the eye is peeled off,
As a result, the adhesive force is removed over substantially the entire surface of the sheet, so that the uppermost sheet can be fed and the second and subsequent sheets can be separated with reliability higher than any of the above claims.

According to the present invention described in claim 5, according to claim 1,
Thus, it is possible to design and develop a feeding device provided with the feeding method according to any one of the fourth to fourth aspects.

According to the sixth aspect of the present invention, by using the feeding device, in addition to the effect of the feeding device according to the fifth aspect, it is possible to reliably prevent the feeding after the feeding device has been left for a long time. The feeding of the uppermost sheet and the separation of the second and subsequent sheets are guaranteed, and the reliability of feeding and separation is improved more than the feeding device of the fifth aspect.

According to the seventh aspect of the present invention, in addition to the effects of the fifth or sixth aspect of the present invention, the feeding of the uppermost sheet is ensured with respect to the feeding after the sheet is supplied. Feeding and separation of the second and subsequent sheets are guaranteed,
The reliability related to feeding and separation is improved more than the feeding device according to claim 5 or claim 6.

According to the present invention as set forth in claim 8, according to claim 5,
In addition to the operation and effect on the feeding device according to any one of claims 7 to 7, the feeding of the uppermost sheet and the separation of the second and subsequent sheets are reliably performed for the feeding with environmental changes to high humidity. Assured, the reliability of feeding and separation is improved over the feeding device of claims 5 to 7.

According to the ninth aspect of the present invention, a fifth aspect is provided.
In addition to the action and effect on the feeding device according to any one of claims 8 to 12, the feeding of the sheet having various surface conditions where high adhesion is a concern is selectively and positively performed on the top sheet. It is possible to promote the feeding and separation of the second and subsequent sheets, and the feeding and separation reliability is improved and more responsive than the feeding device of claims 5 to 7 can be achieved. The range of sheet types is widened and paper-free can be realized.

According to the tenth aspect of the present invention, it is possible to design and develop an image forming apparatus provided with any one of the above-described feeding apparatuses.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a corner claw separation method.

FIG. 2 is a schematic diagram of a friction pad separation method.

FIG. 3 is a schematic diagram of an FRR separation method.

FIG. 4 is a schematic diagram of a feeding method according to the present invention.

FIG. 5 is a schematic diagram of a feeding system according to the present invention. (Primary mode resonance state)

FIG. 6 is a schematic diagram of a feeding system according to the present invention. (Resonance state of secondary mode)

FIG. 7 is a schematic diagram of a resonance mode in a higher order mode.

FIG. 8 is a schematic diagram of reciprocating rotation of a feeding roller.

FIG. 9 is a schematic diagram of a resonance state of the first mode.

FIG. 10 is a schematic diagram of a resonance state of a secondary mode.

FIG. 11 is a schematic diagram of a corner claw separation method according to the present invention.

FIG. 12 is a schematic view of a friction pad separation method according to the present invention.

FIG. 13 is a schematic diagram of an FRR separation method according to the present invention.

FIG. 14 is a schematic diagram of an image forming process using the present invention.

FIG. 15 shows the relationship between the vibration parameter m and the natural frequency f in the order (provided that the sheet density ρ = 700 [kg /
m ³ ], elastic modulus E = 7.00E9 [Pa], L1 = 2
10E-3 / 2 [m]

[Explanation of symbols]

 1: Sheet laminated body 1a: Uppermost sheet 1b, 1c,...: Second and subsequent sheets 2: Tray 3: Arrow indicating feeding direction 4: Feeding roller 5: Separating claw 6: Bottom plate raising means 7: Feeding roller 8: Friction pad 9: Feeding roller (pickup roller) 10: Feeding roller 11: Reverse rotation roller 12: Vibrating means 13: Feeding roller 14: Resonance state of primary mode 15: Secondary mode Resonance state 16: Reciprocating rotation 17: Resonance state of primary mode 18: Resonance state of secondary mode 19: Manual feed unit 20: Bank feed unit

Claims (10)

[Claims] 1. A feeding method for rotating a feeding roller in contact with an uppermost portion of stacked sheets and feeding the uppermost sheet in a feeding direction, wherein the feeding roller is arranged in a stacking direction of the sheets. And vibration means for vibrating in the same direction, and the frequency of the vibration is
The longer one of the distances from the edge of the sheet, which is perpendicular to the feeding direction and on both sides of the sheet, to the feeding roller position is L1, and the longitudinal elastic modulus of the sheet is E. , The paper thickness d, the paper thickness d, and the vibration parameter m which is a positive solution of the relational expression Cos (m) × Coshi (m) = − 1. 4
π)) × (E / (3ρ)) ^(1/2) × (m / L1) ² × d. 2. The sheet feeding method according to claim 1, wherein a reciprocating rotation in which the feeding roller reversely rotates in a direction opposite to the feeding direction during the vibration is added at the same frequency as the frequency of the vibration. Sheet feeding method. 3. The sheet feeding method according to claim 1, wherein the vibration is applied immediately before the sheet is fed. 4. The sheet feeding method according to claim 1, wherein a distance between a sheet edge on each side of the sheet and a sheet feeding roller position in the sheet feeding direction. When the longer one is L2,
(1 / (4π)) × (E / (3ρ)) ^(1/2) ×
(m / L1) ² × d, wherein the sheet feeding method is provided. 5. A sheet feeding apparatus for executing the sheet feeding method according to claim 1. 6. The sheet feeding device according to claim 5, wherein the vibration is applied immediately after sheets are provided in the sheet storage cassette. 7. The sheet feeding device according to claim 5, wherein the vibration is applied immediately after power-on and immediately after use standby. 8. The sheet feeding apparatus according to claim 5, wherein said vibration is applied in an environment having a humidity equal to or higher than a preset humidity by using a temperature detecting means. Feeder. 9. The sheet feeding method according to claim 5, further comprising a user control unit for the vibration, wherein the vibration is applied when requested by a user. . 10. An image forming apparatus comprising the sheet feeding device according to claim 5.