JPH089094Y2 - Paper feeder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a paper feeding device such as a facsimile machine, and more particularly to a structure of a roll paper receiving portion for keeping a load during feeding constant.

[Prior Art] Although many facsimile machines use roll paper as recording paper, the paper feeding device needs to smoothly feed the paper according to the recording speed. It is required to always be constant regardless of the degree of wear.

Conventionally, as the most common structure of the roll paper receiving portion, as shown in FIG. 7, an arc-shaped or U-shaped groove 22 in which a newly set roll paper 21 having a maximum diameter is loosely fitted is formed. Incidentally, when the paper 21a is fed, the paper 21a is sent out while the roll paper 21 rotates in the groove 22. In the case of the structure of this receiving portion, assuming constant-speed feeding, the load due to the frictional force at the contact portion (contact line) P between the roll paper 21 and the groove wall surface 22a corresponds to the feed load F of the paper 21a, The following equation is given from the torque balance equation.

[However, R: roll paper radius, m: roll paper mass, μ: coefficient of friction between groove wall surface 22a and roll paper 21 outer periphery, g: gravity acceleration] From this balance equation, And the load for feeding is reduced as the roll paper 21 is fed and consumed.

In order to solve this load fluctuation problem, not only the arc-shaped or U-shaped groove 22 is loosely fitted as described above, but the roll paper shaft is supported by a spool or a bearing, and the absolute value of the load is In some cases, it is adopted to keep the load constant while reducing

[Problems to be Solved by the Invention] As described above, the roll paper 21 is formed into an arcuate or U-shaped groove.
It is not possible to keep the load constant just by loosely fitting it in 22. On the other hand, although the load can be kept constant by means of the shafts supported by spools, bearings, etc. It becomes necessary to suppress the rotational inertia of
In any case, there are problems that the number of parts of the apparatus increases, the cost increases, and the workability at the time of replacing the roll paper deteriorates.

In view of this, the present invention has a roll paper receiver having a roll paper receiver capable of maintaining a constant load even if the roll paper is consumed by devising the shape of the groove as the roll paper receiver and its wall surface. It was created for the purpose of providing.

[Means for Solving the Problems] The basic structure of the present invention is shown in FIG. 1, and in a paper feeding device using roll paper, the receiving portion of the roll paper 1 is formed as a V-shaped groove 2, and the groove is formed. Width of wall surface 3 in 2 (L1 + L2)
Is a rate of change in which the frictional force between the wall surface 3 of the groove 2 and the contact portion 4 of the roll paper 1 does not change even when the roll paper 1 and the roll paper 1 are decreased and thereby lowered. The present invention relates to the structure of the roll paper receiving portion in the paper feeding device, which is characterized in that

In the figure, the wall surfaces 3 on both sides of the groove 2 are formed by two surfaces, but the number of surfaces is arbitrary, and the point is that the width of the wall surface 3 corresponding to the contact portion 4 changes the frictional force. It is sufficient if it is configured to increase downward at a rate that does not allow it.

[Operation] The roll paper 1 is supported by the groove 2 and is fed to feed the paper 1a while rotating. in this case,
As shown in FIG. 2, as the roll paper 1 is consumed, the mass of the roll paper 1 decreases from m to m ′, and the diameter of the roll paper 1 also decreases. It descends.

By the way, if the wall surface is configured with a certain width, the contact pressure with the wall surface also decreases as the mass of the roll paper decreases, so the frictional force between the wall surface and the roll paper also decreases, and the load decreases. I will be going.

In the present invention, the width (L1 + L2) of the wall surface 3 is formed so as to increase at a predetermined change rate as it goes downward. That is, the contact portion 4 between the outer circumference of the roll paper 1 and the wall surface 3 of the groove 2 changes from P1, P2 to P1 ', P2' as the roll paper 1 is consumed, as shown in FIG. , P1 ′, P2 ′
The width of the wall surface 3 at is larger than the widths at P1 and P2 so that the friction coefficient μ changes at a predetermined rate of change.

Fig. 3 shows the change in mass m due to paper consumption and the friction coefficient μ
The friction coefficient μ is proportional to the width (L1 + L2) of the wall surface 3 if the roughness of the wall surface is constant, and μ =
It is given by k (L1 + L2) [however, k: constant].

Therefore, from the wear of the roll paper 1, that is, the position of the contact portion 4 due to the change in diameter and the mass of the roll paper 1 at that time, a value of the friction coefficient μ that does not change the friction force is obtained, and based on the value By determining the width (L1 + L2) of the wall surface 3 and configuring the wall surface 3 whose width increases as it goes downward, it is possible to configure a receiving portion that does not change the load.

[Embodiment] An embodiment of the present invention will be described below with reference to FIGS. 4 to 6.

FIG. 4 shows the relationship of the forces acting on the roll paper 11 when the roll paper 11 is set in the V-shaped groove 12 which is the receiving portion and is fed by the feed force F. Here, the outer peripheral surface of the roll paper 11 is supported by the contact portions Q1 and Q2 of the wall surfaces 13 and 14, and the paper 11a is fed by the feed force F while the roll paper 11 rotates.

In this case, the force acting on the roll paper 11 from the wall surfaces 13 and 14 becomes 1/2 mg (vertical direction) with F (horizontal direction) at the contact portion Q1 and 1/2 mg (vertical direction) at the contact portion Q2. Vertical direction). Therefore, when these forces are decomposed into the directions of the wall surfaces 13 and 14 and the direction perpendicular thereto, and the forces f1 and f2 involved in the rotational torque of the roll paper 11 at the contact portions Q1 and Q2 are obtained, f1 = (1/2・ Mg ・ COSα-F ・ SINα) + μ (1/2 ・ mg ・ SINα + F ・ COSα) f2 ＝ μ ・ 1/2 ・ mg ・ SINθ −1/2 ・ mg ・ COSθ [however, m: mass of roll paper 11 , Μ: Friction coefficient at Q1, Q2,
g: gravitational acceleration].

On the other hand, since the balance formula regarding the rotation torque of the roll paper 11 is given by F · R = (f1 + f2) · R where R is the radius of the roll paper, F is calculated by substituting the above formula for F = 1. / 2 · mg · {(COSα-COSθ) + μ (SINα + SINθ)} / {(1 + SINα) = μ · COSα}.

By the way, since the mass of the roll paper 11 is proportional to πR ² ,
Is constant regardless of the diameter of the roll paper 11, K / R ² = {(COSα-COSθ) + μ (SINα + SINθ)} / {(1 + SINα) -μ ・ COSα} [however, K: constant ] Is required, and from this formula, μ = {− (COSα−COSθ) R ² + C2} / {(SINα + SINθ) R ² + C1} ... [However, C1, C2: constants].

Further, when the heights of the contact portions Q1 and Q2 from the bottom of the groove 12 are x and y, respectively, and the relation between x and y and R is calculated, R = x · SIN (α + θ) / {1 + COS (α + θ) } = Y · SIN (α + θ) / [COSθ · {1 + COS (α + θ)}], and x, y and R are in a proportional relationship, and from the formula, μ = {-(COSα-COSθ) x ² + C4} / {(SINα + SINθ) x 2 + C3} ... μ = {- (COSα-COSθ) y 2 + C6} / {(SINα + SINθ) y 2 + C5} ... [ However, C3, C4, C5, C6 : constant is obtained.

Therefore, the wall surface when viewed in the direction of arrow AA or BB in FIG. 5 is configured as shown in FIG.
That is, in order to realize the friction coefficient μ given by the above-mentioned formula with respect to changes in x and y, based on the relation of μ = C (W1 + W2) [however, C: constant], the wall surfaces 13 and 14 Width (W1 + W
2) is configured.

As a result, the curves 15, 16, 17, 18 in FIG.
It becomes a hyperbolic curve, and the wall surfaces 13 and 14 always apply a constant frictional force to the roll paper 11 even when the roll paper 11 is consumed, and keep the load constant. Note that C3, C4, C5, and C6 are determined in consideration of known values such as α, θ, mass per unit of paper, and outer diameter of the roll paper 11 before use.

[Advantages of the Invention] As described above, according to the present invention, the roll paper receiving portion of the paper feeding device is formed into a V-shaped groove, and the width of the groove wall surface is changed as it goes downward, so that the roll paper Allows the feed load to be kept constant at all times. That is, the feed load can be made constant without using other parts only by devising the shape of the receiving portion.

Further, as for setting the roll paper, it is sufficient to install the roll paper in the V-shaped groove as compared with the conventional shaft-supporting structure, and therefore, the workability when exchanging the roll paper is excellent.

[Brief description of drawings]

FIG. 1 is a perspective view showing the basic construction of the present invention, FIG. 2 is a side view of the roll paper receiving portion as seen from the axial direction of the roll paper, and FIG. 3 is the horizontal axis showing the consumption of the roll paper. , A graph showing the change in the mass and the friction coefficient of the roll paper with respect to the degree of wear of the paper by taking the mass and the friction coefficient of the roll paper on the vertical axis. Fig. 4 shows the roll from the wall surface of the groove when the paper is being fed. FIG. 5 is a side view of the roll paper receiving portion showing the relationship of the forces acting on the paper, FIG. 5 is a reference side view showing the viewing direction, and FIG. 6 is a front view showing the shape of the wall surface (A- in FIG. 5). FIG. 7 is a side view of a roll paper receiving portion in the prior art. 1 ... Roll paper, 2 ... V-shaped groove 3 ... Wall surface, 4 ... Contact portion, L1 + L2 ... Wall width

Claims (2)

[Scope of utility model registration request] 1. A paper feeding device having a roll paper receiving portion formed of a substantially V-shaped groove so that the loin paper descends downward as the roll paper is consumed. The paper feed device is characterized in that the wall surface is formed so that the frictional force at the contact portion between the wall surface of the roll paper and the roll paper becomes constant as the roll paper descends into the groove. 2. The paper feeding apparatus according to claim 1, wherein the wall surface is formed so that a contact width between the wall surface and the roll paper becomes larger toward the lower side of the groove.