JP3828037B2 - Sheet material feeding method and apparatus, and image forming apparatus including the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet material feeding method and apparatus for separating and feeding sheet materials stacked on a sheet material stacking member one by one from the uppermost sheet material, and an image forming apparatus including the sheet material feeding method.
[0002]
[Prior art]
Conventionally, in the sheet material feeding method in which the stacked sheet materials are separated one by one from the uppermost sheet material positioned at the top and fed to the image forming unit, the sheet material feeding direction A corner nail separation method in which both end portions in the width direction at the tip of the sheet are pressed and separated by a nail member, a separation pad method in which the friction member is pressed to separate the sheet material, and the sheet material is abutted against a fixed gate member having an inclined surface There is a bank separation method.
Of these, a well-known sheet material separation method that can be applied to a wide variety of sheet materials (for example, postcards, envelopes, OHP paper, etc.) including cardboard and thin paper having the same configuration and low size with a small number of parts. Or a bank separation method as disclosed in, for example, Japanese Patent Laid-Open No. 8-91612.
[0003]
[Problems to be solved by the invention]
However, in the conventional sheet feeding method and apparatus using such a separation method, the former separation pad method is particularly low-priced 10 PPM (image forming speed is 10 sheets per minute) or less. In the case of the low-speed machine, an abnormal noise due to sticking slip is generated during conveyance by the sheet material held between the feeding roller and the friction member, so that it is necessary to take measures to make the feeding roller have a half-moon shape. Therefore, it is necessary to provide a pair of cylindrical collars slightly smaller in diameter than the above-mentioned feed roller diameter on the both sides of the feed roller for limiting the ascent of the sheet material stacking member coaxially with the feed roller, As a result, the number of parts increases and production costs increase.
[0004]
Recently, with the increase in the use of recycled paper, there are many cases where the leading edge of the sheet material such as postcards and envelopes has fluttered or burr has occurred during cutting. Therefore, the separation pad method also has a problem that non-feeding of the sheet material is likely to occur.
In addition, the use of backing paper is increasing due to the reuse of copy paper, and there is a risk that the friction coefficient between the stacked sheet materials will increase and double feed may occur. As a result, the sheet material may be curled, and depending on the curl direction, a load may be generated at the leading edge of the sheet material at the separation portion of the sheet material, or the sheet material may not be conveyed to the separation portion and may not be fed.
[0005]
In the case of the separation pad method, since the flat portion of the pad is pressed by the feeding roller, the sheet material is fed out of the stacked state in the conveyance direction (corresponding to the displacement angle of the sheet material stacking member such as the bottom plate). Therefore, the angle of the separation pad must be within a predetermined range. For this purpose, the roller diameter of the feeding roller is limited, and the size of the feeding device cannot be reduced due to restrictions on the freedom of layout. There is also a problem.
On the other hand, in the case of the latter bank separation method, the one disclosed in Japanese Patent Application Laid-Open No. 8-91612 has a flat upper edge portion in contact with the feeding roller and a wide nip portion with the feeding roller. In addition, it becomes difficult to dispose the inclined surface at a predetermined inclination angle due to variations in members and the like.
[0006]
Further, normally, when the uppermost sheet material is conveyed in the image forming unit, the driving of the feeding roller is cut off, but while the preceding sheet material is nipped between the feeding roller and the gate member, The feeding roller is rotated by the frictional force with the sheet material. When the trailing edge of the preceding sheet material passes through the nip portion, the leading edge of the next sheet material is fed to the inclined member by the rotation of the feeding roller. It is done.
At this time, the friction coefficient between the sheet materials is high or varies widely, and the friction coefficient between the next sheet material and the next sheet material is greater than the friction coefficient between the preceding sheet material and the next sheet material. If it is low, there is a possibility that the next sheet material gets over the inclined member, resulting in double feeding.
[0007]
In order to solve the above-mentioned problems, the applicant of the present invention has greatly reduced the influence of the bending elastic modulus of a wide variety of sheet materials with a simple configuration, without causing various sheet materials to be unfed or double-fed. A sheet material feeding apparatus that can separate and feed one sheet at a time has been developed and applied (Japanese Patent Application No. 2002-056456).
This is because the feeding means that presses the stacked uppermost sheet material and feeds the sheet material to the separation unit, and the slant that the leading edge of the sheet material abuts against the feeding means at the nip forming portion. A sheet material feeding device having an inclined member having a surface. In such a separation method of the feeding device, in addition to the separation performance in the nip forming portion composed of the feeding means and the inclined member, the nip forming portion described above after the leading end of the sheet material hits the inclined surface of the inclined member. It has been confirmed that it has separation performance even before reaching. Hereinafter, this is referred to as “pre-separation”, but regarding this pre-separation, the optimum condition of the angle of the inclined surface of the inclined member varies greatly depending on the sheet material type (for example, thick paper, thin paper, OHP paper, etc.).
[0008]
As described above, according to the above-mentioned prior application, the angle formed between the inclined surface of the inclined member and the feeding direction of the sheet material is such that the sheet pressure can be separated without causing double feeding or non-feeding. This is a method that greatly contributes to the setting of the separation pressure area, and the above-mentioned area varies depending on the type of sheet material, but the angle formed between the inclined surface of the inclined member and the sheet material feeding direction is constant. There was no means for setting and changing the angle. For this reason, the difference in the sheet material type has been a major factor causing variations in the above-mentioned region.
The present invention has been made in view of the above points, and an object thereof is to prevent the sheet material from being double-fed and non-fed regardless of the difference in sheet material type.
[0009]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, the present invention provides a feeding means that presses the uppermost sheet material stacked on the sheet material stacking member and feeds the sheet material to the separation section, and a nip forming section for the feeding means. And an inclined member having an inclined surface against which the leading end of the sheet material in a feeding direction comes into contact with the sheet material and rotating the feeding means under conditions satisfying the following conditional expression to separate the sheet material from the separation unit: In the sheet material feeding method of separating only the uppermost sheet material by the inclined surface of the inclined member, or by the inclined surface and the nip forming portion,
Provided is a sheet material feeding method for setting an angle formed between a tangent line of a nip forming portion of the feeding unit and an inclined surface of the inclined member so that the value of (A / B) in the conditional expression is maximized. Is.
P> R_f・ A / (μ₁−μ_p12)
P <R_f・ A / Δμ_p
P> {(A / B) −μ₁} Q / (μ₁−μ_p12) + Μ₁・ R_f・ B / (μ₁−μ_p12)
P <{(A / B) -μ_p12} Q / Δμ_p+ Μ_p12・ R_f・ B / Δμ_p
A = sin θ_p2+ Μ₂・ Cos θ_p2
B = cos θ_p2−μ₂・ Sinθ_p2
θ_p2= Θ₁+ Θ₂-90
Where P: Feed pressure
Q: Separation pressure
R_f: Vertical drag force from the inclined surface of the inclined member acting on the sheet material tip due to bending deformation of the sheet material
μ₁: Friction coefficient between feeding means and sheet material
μ₂: Coefficient of friction between inclined surface of inclined member and sheet material tip
μ_p12: Friction coefficient between the first and second sheets of sheet material
Δμ_p: Difference in friction coefficient between sheet materials
θ₁: An angle formed by the direction in which the separation pressure is applied at the nip forming portion and the tangential direction of the feeding means at the point where the feeding pressure acts
θ₂: Angle formed between the inclined surface of the inclined member and the tangential direction of the feeding means at the point where the feeding pressure acts
θ_p2: Angle formed between the tangent line of the nip forming part of the feeding means and the inclined surface of the inclined member
[0010]
In the same sheet material feeding method, the tangent line of the nip forming portion of the feeding means is set so that the value of (A / B) in the conditional expression is maximized under the conditions satisfying the similar conditional expression. By changing the angle formed between the inclined member and the inclined surface of the inclined member, the angle formed between the pressing direction of the separation pressure in the nip forming portion and the tangential direction of the feeding means at the point where the feeding pressure acts is set. A sheet feeding method is also provided.
In the same sheet material feeding method, the tangent line of the nip forming portion of the feeding means is set so that the value of (A / B) in the conditional expression is maximized under the conditions satisfying the similar conditional expression. By changing the angle formed between the inclined surface of the inclined member and the inclined surface of the inclined member, the sheet material is fed to set the angle formed between the inclined surface of the inclined member and the tangential direction of the feeding means at the point where the feeding pressure acts. It also provides a delivery method.
In the same sheet material feeding method, the tangent line of the nip forming portion of the feeding means is set so that the value of (A / B) in the conditional expression is maximized under the conditions satisfying the similar conditional expression. By changing the angle formed by the inclined surface of the inclined member and the tangential direction of the feeding means at the point where the feeding pressure acts and the pressure direction of the separation pressure in the nip forming portion, and the above A sheet material feeding method is also provided in which an angle formed between the inclined surface of the inclined member and the tangential direction of the feeding means at a point where the feeding pressure acts is set.
[0011]
Further, a feeding means that presses the uppermost sheet material of the sheet material stacked on the sheet material stacking member and feeds the sheet material to the separation unit, and press-contacts the feeding material at the nip forming unit, An inclined member provided with an inclined surface against which the leading end in the feeding direction abuts, and the inclined member forms a contact surface with the feeding means on a ridge along the axial direction of the feeding means. In the sheet material feeding apparatus that satisfies the formula, an angle formed between the tangent line of the nip forming portion of the feeding means and the inclined surface of the inclined member so that the value of (A / B) in the conditional expression is maximized A sheet material feeding device provided with an adjusting means for setting the above is provided.
P> R_f・ A / (μ₁−μ_p12)
P <R_f・ A / Δμ_p
P> {(A / B) −μ₁} Q / (μ₁−μ_p12) + Μ₁・ R_f・ B / (μ₁−μ_p12)
P <{(A / B) -μ_p12} Q / Δμ_p+ Μ_p12・ R_f・ B / Δμ_p
A = sin θ_p2+ Μ₂・ Cos θ_p2
B = cos θ_p2−μ₂・ Sinθ_p2
θ_p2= Θ₁+ Θ₂-90
Where P: Feed pressure
Q: Separation pressure
R_f: Vertical drag from the inclined surface of the inclined member acting on the sheet material tip due to bending deformation of the sheet material
μ₁: Friction coefficient between feeding means and sheet material
μ₂: Coefficient of friction between inclined surface of inclined member and sheet material tip
μ_p12: Friction coefficient between the first and second sheets of sheet material
Δμ_p: Difference in friction coefficient between sheet materials
θ₁: An angle formed by the direction in which the separation pressure is applied at the nip forming portion and the tangential direction of the feeding means at the point where the feeding pressure acts
θ₂: Angle formed between the inclined surface of the inclined member and the tangential direction of the feeding means at the point where the feeding pressure acts
θ_p2: Angle formed between the tangent line of the nip forming part of the feeding means and the inclined surface of the inclined member
[0012]
By changing the angle formed between the tangent line of the nip forming portion of the feeding means and the inclined surface of the inclined member under a condition that satisfies the same conditional expression, the same sheet material feeding device, The angle formed by the separation pressure pressing direction in the nip forming portion and the tangential direction of the sheet feeding means at the point where the feeding pressure acts is set so that the value of (A / B) in the conditional expression is maximized. There is also provided a sheet material feeding device provided with an adjusting means.
By changing the angle formed between the tangent line of the nip forming portion of the feeding means and the inclined surface of the inclined member under a condition that satisfies the same conditional expression, the same sheet material feeding device, The angle formed by the pressurizing direction of the separation pressure in the nip forming portion and the tangential direction of the feeding means at the point where the feeding pressure acts so that the value of (A / B) in the conditional expression is maximized, and There is also provided a sheet material feeding device provided with adjusting means for setting both the angle formed by the inclined surface of the inclined member and the tangential direction of the feeding means at the point where the feeding pressure acts.
Furthermore, an image forming apparatus including any one of the sheet material feeding devices described above and an image forming unit that forms an image on the sheet material fed from the sheet material feeding device is also provided.
Here, the feeding means may be a feeding belt as well as a feeding roller.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be specifically described below with reference to the drawings.
FIG. 1 is a longitudinal sectional view showing a first embodiment of the present invention, FIG. 2 is an exploded perspective view showing the entire configuration thereof, and FIG. 3 is an explanatory view showing a part of FIG.
First, an overall configuration of a sheet material feeding apparatus according to the present invention will be described with reference to FIGS. 1 and 2. A cassette 11 is detachably attached to a shallow bowl-shaped device body 10 having a low wall surface on all four sides through a side opening 10b. In this cassette 11, a bottom plate 1, which is a sheet material stacking member capable of stacking a plurality of sheet materials 2 shown in FIG. 1, is supported at one end by a support shaft 1 a so as to be freely slidable. The free end portion is always urged upward in FIG.
[0014]
The apparatus main body 10 is fed with feeding means so as to be able to come into pressure contact with the tip of the uppermost sheet material 2a of the sheet material 2 loaded on the bottom plate 1 having a counterclockwise biasing force in FIG. The abutting surface 6b of the inclined member 6 having the inclined surface 6a is pressed against the feeding roller 4 by the urging force of the compression spring 5, thereby separating the sheet material. Is configured.
As shown in FIG. 2, the inclined member 6 is slidably guided by guide rails 8 and 8 on the apparatus main body 10 side so that the ribs 6d and 6d projecting from the left and right side surfaces are pressed against the feeding roller 4. A pair of hooks 6f, 6f for preventing the extension are extended at the lower part and engaged with a locking part (not shown) of the apparatus main body 10 so that the upper limit is restricted. ing. On the downstream side of the inclined member 6, only one conveying roller pair 7 (only one is shown in FIG. 2) that conveys the sheet material 2 fed by the feeding roller 4 to an image forming unit of an image forming apparatus (not shown). ) Is rotatably supported.
The parallel movement means of the inclined member 6 may be provided with a guide rail on the inclined member 6 side and a rib on the apparatus main body 10 side.
[0015]
As shown in an enlarged view in FIG. 3, the inclined member 6 is a thin-walled member having an inclined member main body 6g and one end pivotably attached to a fixed support shaft 6k at the upper left end of the inclined member main body 6g. The first arm 6h, the thin second arm 6i pivotally mounted at one end on the free support shaft 6m at the other end of the first arm 6h, and the other end of the second arm 6i Has a crank mechanism composed of a thin third arm 6j connected to a unidirectional support shaft 6n movable only in the direction of the arrow α, and the third arm 6j is a guide groove 6p of the inclined member body 6g. It is possible to reciprocate in the direction indicated by arrow α.
With such a configuration, when the third arm 6j reciprocates in the direction indicated by arrow α, the first arm 6h can be pivotally rotated in the direction indicated by arrow β about the fixed support shaft 6k. The angle of the inclined surface 6a formed by one arm 6h can be changed. In addition, by covering the elastic metal plate 6A subjected to the press bending process from the inclined member main body 6g side to the first arm 6h, wear of the first arm 6h contacting the sheet material can be prevented. .
[0016]
FIG. 4 shows a second embodiment of the present invention. A second arm 6i connected to the first arm 6h of the first embodiment shown in FIG. 3 by a free support shaft 6m is extended rightward in the drawing. Then, the one-way support shaft 6n at the other end is connected to the corner arm 6J, and the operation member 6s is projected from the corner arm 6J. Further, a guide groove 9a is formed in the side fence 9 that regulates the width direction of the sheet material, a long hole 9b is provided in the guide groove 9a, and the square arm 6J is slidably mounted in the guide groove 9a. The operating member 6s is inserted into the hole 9b, and the operating member 6s is moved so that the inclination angle of the first arm 6h can be freely changed.
[0017]
The operation of the sheet material feeding method and apparatus according to the present invention will be theoretically described below.
FIG. 5 is an enlarged explanatory view showing the separation portion of the sheet material, and the sheet material 2 is kept horizontal. Thus, when the sheet feeding angle of the sheet material is horizontal, the lowest point of the feeding roller 4 is the point of action of the feeding pressure P, and when this point X is the origin, the feeding roller 4 and the inclined member. A contact point with the inclined surface 6 a of 6 is a nip forming portion N.
With this configuration:
r: radius of feeding roller
P: Feed pressure
Q: Separation pressure
μ₁: Coefficient of friction between feeding roller and sheet material
μ₂: Coefficient of friction between inclined surface of inclined member and sheet material tip
μ_p12: Friction coefficient between the first and second sheets of sheet material
Δμ_p: Difference in friction coefficient between sheet materials
θ₁: An angle formed between the pressing direction of the separation pressure Q in the nip forming portion N and the tangential direction of the feeding roller at the point where the feeding pressure P acts.
θ₂: Angle formed between the inclined surface of the inclined member and the tangential direction of the feeding roller at the point where the feeding pressure P acts
θ_p2: The angle formed by the tangent line of the nip forming portion of the feeding roller and the inclined surface of the inclined member.
[0018]
here
θ_p2= Θ₁+ Θ₂-90 (1)
The coordinates of the nip forming portion N (N_x, N_y) Is as follows.
N_x= R · cos (−θ₁(2.1)
N_y= R + r · sin (−θ₁(2.2)
Next, an inequality is created from the relationship between the forces acting on the sheet material 2. In the present invention, the area until the front end of the sheet material 2 reaches the nip forming portion N and the nip entering process held by the nip forming portion N. These will be described with reference to FIGS. 6, 7, and 8 respectively.
[0019]
Referring to FIG. 6, immediately before the nip, the front end of the sheet material 2 is perpendicular to the vertical drag R from the inclined surface 6 a of the inclined member 6._fAct. In order for the leading edge of the sheet material 2 to reach the nip forming portion N, bending deformation is required. At this time, the force acting on the leading edge of the sheet material differs depending on the type of the sheet material, and becomes large for thick paper.
It is assumed that the front end of the sheet material is in the same direction as the tangent to the outer periphery of the feed roller at the nip forming portion N, and the front end of the sheet material is not in contact with other members except at the position where the feed pressure acts. The conveying force of the uppermost sheet material 2a is (μ₁−μ_p12) ・ P, double feed force is Δμ_p・ Because it is P, in order to prevent non-feed NF,
(Μ₁−μ_p12) ・ P> R_f・ A
∴P> R_f・ A / (μ₁−μ_p12(3)
To prevent double feed MF,
Δμ_p・ P> R_f・ A
∴P <R_f・ A / Δμ_p                (4)
A = sin θ_p2+ Μ₂・ Cos θ_p2  (5)
[0020]
Next, a process in which the leading edge of the sheet material enters the nip forming portion will be described with reference to FIGS. At this time, the leading edge of the sheet material is perpendicular to the vertical drag Q_nAnd its frictional force μ₂・ Q_nReceive. On the other hand, the vertical drag F is caused by the force caused by the leading edge of the sheet from the feeding roller._nAnd friction force in the conveying direction μ₁・ F_nReceive. Therefore, the separation pressure Q is
F_n+ R_f・ B = Q (6)
Q_n・ B = Q (7)
B = cos θ_p2−μ₂・ Sinθ_p2  (8)
Further, as a condition for preventing the non-feed in the longitudinal direction of the sheet material, from the above formulas (6) and (7)
(Μ₁−μ_p12) ・ P + μ₁・ F_n> Q_n・ A
∴P> {(A / B) -μ₁} Q / (μ₁−μ_p12)
+ Μ₁・ R_f・ B / (μ₁−μ_p12(9)
[0021]
As a condition to prevent double feeding,
Δμ_P・ P + μ_p12・ F_n<Q_n・ A
Substituting equations (6) and (7) into this
P <{(A / B) -μ_p12} Q / Δμ_p
+ Μ_p12・ R_f・ B / Δμ_p      (10)
Summarizing the coefficients of Equations (9) and (10) together,
As a conditional expression for preventing non-feed
P> C ・ Q + D (11)
As a conditional expression to prevent double feed
P <G · Q + H (12)
However,
C = {(A / B) -μ₁} / (Μ₁−μ_p12(13)
D = μ₁・ R_f・ B / (μ₁−μ_p12(14)
G = {(A / B) -μ_p12} / Δμ_p            (15)
H = μ_p12・ R_f・ B / Δμ_p                (16)
[0022]
From the above formula, the suitable area formed by the feeding pressure P and the separation pressure Q in the process in which the leading edge of the sheet material enters the nip forming portion is large to the values of C and G in the formulas (11) and (12). It can be seen that the values of C and G depend on the value of (A / B) in the equations (13) and (15). The values of A and B are the angles θ from the equations (5) and (8), respectively._p2Is given by the function of_p2It can be seen that the value of (A / B) can be adjusted by adjusting the value of.
Further, from the equation (15), the slope of the boundary line on the double feeding side of the suitable area is the difference Δμ in the friction coefficient between the sheet materials._pIt can be seen that the value of (A / B) is set to be as large as possible, so that Δμ_pIt is possible to ensure a sufficient aptitude region margin even with respect to fluctuations in the range.
[0023]
Next, FIG. 9 and FIG. 10 show a third embodiment of the present invention, FIG. 9 is an exploded perspective view showing the overall configuration, and FIG. 10 is an explanatory view showing a part thereof enlarged. In this embodiment, the feeding roller 4 is held by a holding member 12 so as to be swingable about a shaft 13, and weights 14 and 14 are provided at both ends of the rotating shaft 4 a of the feeding roller 4 to contact the inclined member 16. It is pressed against the surface 16b, thereby constituting a separation portion for the sheet material.
Both ends of the inclined member 16 are pivotally supported by the apparatus main body 10 with support shafts 15, 15, and a recess 16 c that can be engaged with one end of a second arm 17 b of a crank mechanism 17, which will be described later, is provided at the lower part. As shown in FIG. 10, the compression spring 5 is engaged with the fixed portion of the apparatus body 10 and is urged clockwise in FIG. The second arm 17b is connected to one end of the first arm 17a by a support shaft 17c, and the other end of the first arm 17a is connected to the tip of the bottom plate 1 by a support shaft 1b. It is pivotally supported on the cassette 11 by a support shaft 1a (FIG. 9).
With such a configuration, when the bottom plate 1 swings and rotates around the support shaft 1 a according to the amount of the stacked sheet material, the second arm 17 b causes the inclined member 16 of the compression spring 5 through the first arm 17 a. The angle of the inclined surface 16a of the inclined member 16 can be automatically adjusted according to the swinging position of the bottom plate 1 by rotating around the support shaft 15 by the urging force or against the urging force. In the above embodiment, the inclined member 16 and the second arm 17b can be directly connected via an axis.
[0024]
FIG. 11 is an exploded perspective view showing a fourth embodiment of the present invention in which a part of the third embodiment is changed. In this embodiment, two ribs 18 and 18 (only one side surface is shown in the figure) are provided on the upper and lower sides of the both sides of the inclined member 16, respectively. The positioning hook 21 is slidably loosely fitted into the plurality of formed guide grooves 19 and is inserted into the positioning grooves 20 formed in the apparatus main body 10. Is the same as in the previous third embodiment.
According to this embodiment, the locking position in the sliding direction is determined by inserting the positioning hook 21 of the inclined member 16 into the positioning groove 20 of the apparatus main body 10. Therefore, by changing the position of the positioning groove 20 The pressing direction of the separation pressure Q can be adjusted.
[0025]
12 and 13 show a fifth embodiment of the present invention, FIG. 12 is an exploded perspective view thereof, and FIG. 13 is an explanatory view showing a part thereof enlarged. In this embodiment, the inclined member 16 is loosely fitted with a plurality of ribs 18 provided on the upper and lower sides of the both sides in a plurality of guide grooves 19 of the apparatus body 10 so as to be slidable, and a recess 16c is provided in the lower part thereof. . Other configurations are the same as those of the third embodiment shown in FIGS.
According to such a configuration, when the bottom plate 1 is pivotally rotated about the support shaft 1a, the second arm 17b is moved to the concave portion 16c of the inclined member 16 by the urging force of the compression spring 5 or against the urging force. The position of the inclined member 16 is adjusted by contact. Thereby, the pressing direction of the separation pressure Q and the action point position of the feeding pressure P shown in FIG. 5 can be adjusted.
[0026]
Next, FIG. 14 is a configuration diagram of a copying machine as an example of an image forming apparatus provided with the above-described sheet material feeding device.
In this copying machine 30, a latent image is formed on a photosensitive drum 35 provided in an image forming system 34 by an optical writing system 33 based on image data read by an optical reading system 32 provided in the copying machine main body 31. The latent image is formed, and the developing device 36 of the image forming system 34 makes the visible image with toner.
The above-described feeding device P1 is provided at the lower part of the copying machine main body 31, and the sheet material 2 stacked on the bottom plate 1 is fed one by one by the feeding roller 4 from the cassette 11 of the feeding device P1. The conveying roller pair 7 conveys the visible image on the photosensitive drum 35 onto the sheet material 2 through the conveying path 37 to the image forming system 34.
[0027]
When the transfer is completed, the sheet material 2 is conveyed to the fixing device 38 to fix the visible image, and then discharged to the external paper discharge tray 40 by the paper discharge roller pair 39. Further, during the double-sided image formation, the sheet material 2 is conveyed from the reverse conveyance path 41 to the double-sided device 42 by a discharge branching claw (not shown), temporarily stored in the double-sided tray 43, and then reverses the traveling direction. The image is again sent from 44 to the image forming system 34, an image is formed on the back surface, and is discharged onto the discharge tray 40 through the fixing device 38.
In FIG. 66, only one sheet feeding device P1 is shown to simplify the drawing. However, a plurality of sheet feeding devices having different sizes can be provided as necessary. The image forming apparatus having the apparatus is not limited to a copying machine, and can be applied to a facsimile, a printer, or the like without any trouble.
[0028]
【The invention's effect】
As described above, according to the sheet material feeding method and apparatus according to the present invention, the sheet material greatly contributes to the appropriate region between the feeding pressure and the separation pressure in the process of the leading edge of the sheet material entering the nip forming portion. The angle formed between the inclined surface of the inclined member and the entry direction of the sheet material can be adjusted. Thereby, it is possible to realize continuous conveyance of the sheet material while maintaining the appropriate region without being affected by the sheet material type or the like.
Further, according to the image forming apparatus provided with the sheet material feeding device, it is possible to reliably separate a wide variety of sheet materials one by one without unfeeding or multi-feeding, and to feed them to the image forming unit. It is possible to form an image without selecting the.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing a schematic configuration of a sheet material feeding device according to a first embodiment of the present invention.
FIG. 2 is an exploded perspective view showing the overall configuration.
FIG. 3 is an explanatory diagram showing an enlarged part of FIG. 1;
FIG. 4 is a perspective view showing an essential part of a second embodiment of the present invention.
FIG. 5 is an explanatory diagram for explaining the operation theory of the sheet material feeding method and apparatus according to the present invention.
FIG. 6 is an explanatory view showing a force relationship acting on the leading edge of the sheet material just before the nip.
FIG. 7 is an explanatory view showing the force relationship acting on the leading edge of the sheet material in the initial stage of the nip entry process.
FIG. 8 is an explanatory view showing the force relationship acting on the leading edge of the sheet material in the latter half of the nip entry process.
FIG. 9 is an exploded perspective view showing an overall configuration of a third embodiment of the present invention.
FIG. 10 is an explanatory view showing a part of the same in an enlarged manner.
FIG. 11 is an exploded perspective view showing an overall configuration of a fourth embodiment of the present invention.
FIG. 12 is an exploded perspective view showing an overall configuration of a fifth embodiment of the present invention.
FIG. 13 is an explanatory diagram showing an enlarged part of the same.
FIG. 14 is a configuration diagram illustrating an example of an image forming apparatus including the sheet material feeding device.
[Explanation of symbols]
1: Bottom plate (sheet material stacking member)
2: Sheet material
4: Feeding roller (feeding means)
6, 16: Inclined member 17: Crank mechanism
30: Copying machine (image forming apparatus)
P: Feed pressure Q: Separation pressure
N: Nip forming part

Claims (9)

A feeding unit that presses the uppermost sheet material stacked on the sheet material stacking member and feeds the sheet material to the separation unit, and a nip forming unit that press-contacts the sheet material to the separation unit, and a leading end in the feeding direction of the sheet material An inclined member having an abutting inclined surface, and under the condition satisfying the following conditional expression, the feeding means is rotated to feed the sheet material to the separation unit, and the fed sheet material is In the sheet material feeding method in which only the uppermost sheet material is separated by the inclined surface of the inclined member or by the inclined surface and the nip forming portion,
The sheet material feeding method is characterized in that an angle formed between a tangent of a nip forming portion of the feeding unit and an inclined surface of the inclined member is set so that a value of (A / B) in the conditional expression is maximized. Delivery method.
P> R _f · A / (μ ₁ −μ _p12 )
P <R _f · A / Δμ _p
P> {(A / B) −μ ₁ } Q / (μ ₁ −μ _p12 ) + μ ₁ · R _f · B / (μ ₁ −μ _p12 )
P <{(A / B) −μ _p12 } Q / Δμ _p + μ _p12 · R _f · B / Δμ _p
A = sin θ _p2 + μ ₂ · cos θ _p2
B = cos θ _p2 −μ ₂ · sin θ _p2
θ _p2 = θ ₁ + θ ₂ −90
However P: feeding pressure Q: separation pressure R _f: friction coefficient between the feeding means and the sheet _material: the bending deformation of the sheet material, the normal force from the inclined surface of the inclined member which acts on the sheet material front edge mu ₁ μ ₂ : Friction coefficient between the inclined surface of the inclined member and the front end of the sheet material μ _p12 : Friction coefficient between the first and second sheets of the sheet material Δμ _p : Difference in friction coefficient between the sheet materials θ ₁ : Angle θ ₂ formed by the direction in which the separation pressure is applied at the nip forming portion and the tangential direction of the feeding means at the point where the feeding pressure acts: The slope of the inclined member and the feeding means at the point where the feeding pressure acts Angle θ _p2 formed with the tangential direction: Angle formed between the tangent line of the nip forming portion of the feeding means and the inclined surface of the inclined member A feeding unit that presses the uppermost sheet material stacked on the sheet material stacking member and feeds the sheet material to the separation unit, and a nip forming unit that press-contacts the sheet material to the separation unit, and a leading end in the feeding direction of the sheet material An inclined member having an abutting inclined surface, and under the condition satisfying the following conditional expression, the feeding means is rotated to feed the sheet material to the separation unit, and the fed sheet material is In the sheet material feeding method in which only the uppermost sheet material is separated by the inclined surface of the inclined member or by the inclined surface and the nip forming portion,
By changing the angle formed between the tangent line of the nip forming portion of the feeding means and the inclined surface of the inclined member so that the value of (A / B) in the conditional expression is maximized, the separation in the nip forming portion is performed. A sheet material feeding method, characterized in that an angle formed between a pressing direction of pressure and a tangential direction of the feeding means at a point where feeding pressure acts is set.
P> R _f · A / (μ ₁ −μ _p12 )
P <R _f · A / Δμ _p
P> {(A / B) −μ ₁ } Q / (μ ₁ −μ _p12 ) + μ ₁ · R _f · B / (μ ₁ −μ _p12 )
P <{(A / B) −μ _p12 } Q / Δμ _p + μ _p12 · R _f · B / Δμ _p
A = sin θ _p2 + μ ₂ · cos θ _p2
B = cos θ _p2 −μ ₂ · sin θ _p2
θ _p2 = θ ₁ + θ ₂ −90
However P: feeding pressure Q: separation pressure R _f: friction coefficient between the feeding means and the sheet _material: the bending deformation of the sheet material, the normal force from the inclined surface of the inclined member which acts on the sheet material front edge mu ₁ μ ₂ : Friction coefficient between the inclined surface of the inclined member and the front end of the sheet material μ _p12 : Friction coefficient between the first and second sheets of the sheet material Δμ _p : Difference in friction coefficient between the sheet materials θ ₁ : Angle θ ₂ formed by the direction in which the separation pressure is applied at the nip forming portion and the tangential direction of the feeding means at the point where the feeding pressure acts: The slope of the inclined member and the feeding means at the point where the feeding pressure acts Angle θ _p2 formed with the tangential direction: Angle formed between the tangent line of the nip forming portion of the feeding means and the inclined surface of the inclined member A feeding unit that presses the uppermost sheet material stacked on the sheet material stacking member and feeds the sheet material to the separation unit, and a nip forming unit that press-contacts the sheet material to the separation unit, and a leading end in the feeding direction of the sheet material An inclined member having an abutting inclined surface, and under the condition satisfying the following conditional expression, the feeding means is rotated to feed the sheet material to the separation unit, and the fed sheet material is In the sheet material feeding method in which only the uppermost sheet material is separated by the inclined surface of the inclined member or by the inclined surface and the nip forming portion,
By changing the angle formed between the tangent of the nip forming portion of the feeding means and the inclined surface of the inclined member so that the value of (A / B) in the conditional expression is maximized, the inclined surface of the inclined member The sheet material feeding method is characterized in that an angle formed by a tangential direction of the feeding means at a point where the feeding pressure acts is set.
P> R _f · A / (μ ₁ −μ _p12 )
P <R _f · A / Δμ _p
P> {(A / B) −μ ₁ } Q / (μ ₁ −μ _p12 ) + μ ₁ · R _f · B / (μ ₁ −μ _p12 )
P <{(A / B) −μ _p12 } Q / Δμ _p + μ _p12 · R _f · B / Δμ _p
A = sin θ _p2 + μ ₂ · cos θ _p2
B = cos θ _p2 −μ ₂ · sin θ _p2
θ _p2 = θ ₁ + θ ₂ −90
However P: feeding pressure Q: separation pressure R _f: friction coefficient between the feeding means and the sheet _material: the bending deformation of the sheet material, the normal force from the inclined surface of the inclined member which acts on the sheet material front edge mu ₁ μ ₂ : Friction coefficient between the inclined surface of the inclined member and the front end of the sheet material μ _p12 : Friction coefficient between the first and second sheets of the sheet material Δμ _p : Difference in friction coefficient between the sheet materials θ ₁ : Angle θ ₂ formed by the direction in which the separation pressure is applied at the nip forming portion and the tangential direction of the feeding means at the point where the feeding pressure acts: The slope of the inclined member and the feeding means at the point where the feeding pressure acts Angle θ _p2 formed with the tangential direction: Angle formed between the tangent line of the nip forming portion of the feeding means and the inclined surface of the inclined member A feeding unit that presses the uppermost sheet material stacked on the sheet material stacking member and feeds the sheet material to the separation unit, and a nip forming unit that press-contacts the sheet material to the separation unit, and a leading end in the feeding direction of the sheet material An inclined member having an abutting inclined surface, and under the condition satisfying the following conditional expression, the feeding means is rotated to feed the sheet material to the separation unit, and the fed sheet material is In the sheet material feeding method in which only the uppermost sheet material is separated by the inclined surface of the inclined member or by the inclined surface and the nip forming portion,
By changing the angle formed between the tangent line of the nip forming portion of the feeding means and the inclined surface of the inclined member so that the value of (A / B) in the conditional expression is maximized, the separation in the nip forming portion is performed. The angle formed between the pressure application direction and the tangential direction of the feeding means at the point where the feeding pressure acts, and the tangential direction of the feeding means at the point where the inclined surface of the inclined member and the feeding pressure act The sheet material feeding method is characterized in that the angle between the sheet materials is set together.
P> R _f · A / (μ ₁ −μ _p12 )
P <R _f · A / Δμ _p
P> {(A / B) −μ ₁ } Q / (μ ₁ −μ _p12 ) + μ ₁ · R _f · B / (μ ₁ −μ _p12 )
P <{(A / B) −μ _p12 } Q / Δμ _p + μ _p12 · R _f · B / Δμ _p
A = sin θ _p2 + μ ₂ · cos θ _p2
B = cos θ _p2 −μ ₂ · sin θ _p2
θ _p2 = θ ₁ + θ ₂ −90
However P: feeding pressure Q: separation pressure R _f: friction coefficient between the feeding means and the sheet _material: the bending deformation of the sheet material, the normal force from the inclined surface of the inclined member which acts on the sheet material front edge mu ₁ μ ₂ : Friction coefficient between the inclined surface of the inclined member and the front end of the sheet material μ _p12 : Friction coefficient between the first and second sheets of the sheet material Δμ _p : Difference in friction coefficient between the sheet materials θ ₁ : Angle θ ₂ formed by the direction in which the separation pressure is applied at the nip forming portion and the tangential direction of the feeding means at the point where the feeding pressure acts: The slope of the inclined member and the feeding means at the point where the feeding pressure acts Angle θ _p2 formed with the tangential direction: Angle formed between the tangent line of the nip forming portion of the feeding means and the inclined surface of the inclined member A feeding unit that presses the uppermost sheet material stacked on the sheet material stacking member and feeds the sheet material to the separation unit; and a feeding direction of the sheet material that is pressed against the feeding unit by a nip forming unit And an inclined member having an inclined surface against which the tip of the abutting member is provided, and the inclined member forms a contact surface with the feeding means on a ridge along the axial direction of the feeding means, and has the following conditional expression: In a satisfactory sheet material feeding device,
Adjusting means for setting an angle formed by a tangent line of the nip forming portion of the feeding means and the inclined surface of the inclined member so that the value of (A / B) in the conditional expression is maximized; Sheet material feeding device.
P> R _f · A / (μ ₁ −μ _p12 )
P <R _f · A / Δμ _p
P> {(A / B) −μ ₁ } Q / (μ ₁ −μ _p12 ) + μ ₁ · R _f · B / (μ ₁ −μ _p12 )
P <{(A / B) −μ _p12 } Q / Δμ _p + μ _p12 · R _f · B / Δμ _p
A = sin θ _p2 + μ ₂ · cos θ _p2
B = cos θ _p2 −μ ₂ · sin θ _p2
θ _p2 = θ ₁ + θ ₂ −90
However P: feeding pressure Q: separation pressure R _f: friction coefficient between the feeding means and the sheet _material: the bending deformation of the sheet material, the normal force from the inclined surface of the inclined member which acts on the sheet material front edge mu ₁ μ ₂ : Friction coefficient between the inclined surface of the inclined member and the front end of the sheet material μ _p12 : Friction coefficient between the first and second sheets of the sheet material Δμ _p : Difference in friction coefficient between the sheet materials θ ₁ : Angle θ ₂ formed by the direction in which the separation pressure is applied at the nip forming portion and the tangential direction of the feeding means at the point where the feeding pressure acts: The slope of the inclined member and the feeding means at the point where the feeding pressure acts Angle θ _p2 formed with the tangential direction: Angle formed between the tangent line of the nip forming portion of the feeding means and the inclined surface of the inclined member A feeding unit that presses the uppermost sheet material stacked on the sheet material stacking member and feeds the sheet material to the separation unit; and a feeding direction of the sheet material that is pressed against the feeding unit by a nip forming unit And an inclined member having an inclined surface against which the tip of the abutting member is provided, and the inclined member forms a contact surface with the feeding means on a ridge along the axial direction of the feeding means, and has the following conditional expression: In a satisfactory sheet material feeding device,
By changing the angle formed between the tangent line of the nip forming portion of the feeding means and the inclined surface of the inclined member, separation in the nip forming portion is performed so that the value of (A / B) in the conditional expression is maximized. An apparatus for feeding a sheet material, characterized in that an adjusting means is provided for setting an angle formed between a pressing direction of pressure and a tangential direction of the feeding means at a point where the feeding pressure acts.
P> R _f · A / (μ ₁ −μ _p12 )
P <R _f · A / Δμ _p
P> {(A / B) −μ ₁ } Q / (μ ₁ −μ _p12 ) + μ ₁ · R _f · B / (μ ₁ −μ _p12 )
P <{(A / B) −μ _p12 } Q / Δμ _p + μ _p12 · R _f · B / Δμ _p
A = sin θ _p2 + μ ₂ · cos θ _p2
B = cos θ _p2 −μ ₂ · sin θ _p2
θ _p2 = θ ₁ + θ ₂ −90
However P: feeding pressure Q: separation pressure R _f: friction coefficient between the feeding means and the sheet _material: the bending deformation of the sheet material, the normal force from the inclined surface of the inclined member which acts on the sheet material front edge mu ₁ μ ₂ : Friction coefficient between the inclined surface of the inclined member and the front end of the sheet material μ _p12 : Friction coefficient between the first and second sheets of the sheet material Δμ _p : Difference in friction coefficient between the sheet materials θ ₁ : Angle θ ₂ formed by the direction in which the separation pressure is applied at the nip forming portion and the tangential direction of the feeding means at the point where the feeding pressure acts: The slope of the inclined member and the feeding means at the point where the feeding pressure acts Angle θ _p2 formed with the tangential direction: Angle formed between the tangent line of the nip forming portion of the feeding means and the inclined surface of the inclined member A feeding unit that presses the uppermost sheet material stacked on the sheet material stacking member and feeds the sheet material to the separation unit; and a feeding direction of the sheet material that is pressed against the feeding unit by a nip forming unit And an inclined member having an inclined surface against which the tip of the abutting member is provided, and the inclined member forms a contact surface with the feeding means on a ridge along the axial direction of the feeding means, and has the following conditional expression: In a satisfactory sheet material feeding device,
By changing the angle formed between the tangent line of the nip forming portion of the feeding means and the inclined surface of the inclined member, the inclined surface of the inclined member is set so that the value of (A / B) in the conditional expression is maximized. And an adjusting means for setting an angle formed by a tangential direction of the feeding means at a point where the feeding pressure acts.
P> R _f · A / (μ ₁ −μ _p12 )
P <R _f · A / Δμ _p
P> {(A / B) −μ ₁ } Q / (μ ₁ −μ _p12 ) + μ ₁ · R _f · B / (μ ₁ −μ _p12 )
P <{(A / B) −μ _p12 } Q / Δμ _p + μ _p12 · R _f · B / Δμ _p
A = sin θ _p2 + μ ₂ · cos θ _p2
B = cos θ _p2 −μ ₂ · sin θ _p2
θ _p2 = θ ₁ + θ ₂ −90
However P: feeding pressure Q: separation pressure R _f: friction coefficient between the feeding means and the sheet _material: the bending deformation of the sheet material, the normal force from the inclined surface of the inclined member which acts on the sheet material front edge mu ₁ μ ₂ : Friction coefficient between the inclined surface of the inclined member and the front end of the sheet material μ _p12 : Friction coefficient between the first and second sheets of the sheet material Δμ _p : Difference in friction coefficient between the sheet materials θ ₁ : Angle θ ₂ formed by the direction in which the separation pressure is applied at the nip forming portion and the tangential direction of the feeding means at the point where the feeding pressure acts: The slope of the inclined member and the feeding means at the point where the feeding pressure acts Angle θ _p2 formed with the tangential direction: Angle formed between the tangent line of the nip forming portion of the feeding means and the inclined surface of the inclined member A feeding unit that presses the uppermost sheet material stacked on the sheet material stacking member and feeds the sheet material to the separation unit; and a feeding direction of the sheet material that is pressed against the feeding unit by a nip forming unit And an inclined member having an inclined surface against which the tip of the abutting member is provided, and the inclined member forms a contact surface with the feeding means on a ridge along the axial direction of the feeding means, and has the following conditional expression: In a satisfactory sheet material feeding device,
By changing the angle formed between the tangent line of the nip forming portion of the feeding means and the inclined surface of the inclined member, separation in the nip forming portion is performed so that the value of (A / B) in the conditional expression is maximized. The angle formed between the pressure application direction and the tangential direction of the feeding means at the point where the feeding pressure acts, and the tangential direction of the feeding means at the point where the inclined surface of the inclined member and the feeding pressure act An apparatus for feeding a sheet material, characterized in that an adjusting means for setting both angles is provided.
P> R _f · A / (μ ₁ −μ _p12 )
P <R _f · A / Δμ _p
P> {(A / B) −μ ₁ } Q / (μ ₁ −μ _p12 ) + μ ₁ · R _f · B / (μ ₁ −μ _p12 )
P <{(A / B) −μ _p12 } Q / Δμ _p + μ _p12 · R _f · B / Δμ _p
A = sin θ _p2 + μ ₂ · cos θ _p2
B = cos θ _p2 −μ ₂ · sin θ _p2
θ _p2 = θ ₁ + θ ₂ −90
However P: feeding pressure Q: separation pressure R _f: friction coefficient between the feeding means and the sheet _material: the bending deformation of the sheet material, the normal force from the inclined surface of the inclined member which acts on the sheet material front edge mu ₁ μ ₂ : Friction coefficient between the inclined surface of the inclined member and the front end of the sheet material μ _p12 : Friction coefficient between the first and second sheets of the sheet material Δμ _p : Difference in friction coefficient between the sheet materials θ ₁ : Angle θ ₂ formed by the direction in which the separation pressure is applied at the nip forming portion and the tangential direction of the feeding means at the point where the feeding pressure acts: The slope of the inclined member and the feeding means at the point where the feeding pressure acts Angle θ _p2 formed with the tangential direction: Angle formed between the tangent line of the nip forming portion of the feeding means and the inclined surface of the inclined member An image forming apparatus comprising: the sheet material feeding device according to claim 5; and an image forming unit that forms an image on the sheet material fed from the sheet material feeding device.

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