JP2001151373A - Sheet conveying device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily secure cleaning performance of a sheet conveying body such as a conveying roll by employing a new designing method. SOLUTION: The sheet conveying device comprises the sheet conveying body that contacts with a sheet and conveys the sheet, and a cleaning roll that is connected by pressure with the sheet conveying body and cleans the sheet conveying body by following and rotating with the sheet conveying body. A nip pressure FN(N) applied to a nip portion between the sheet conveying body and the cleaning roll, a tangent directional load FL(N) applied oppositely to the moving direction of the cleaning roll of tangent directional forces FT(N) applied in the tangent direction of the cleaning roll of the nip portion, and a friction coefficient μa between the sheet conveying body and the cleaning roll satisfy the relation FL<μaFN.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet conveying apparatus for conveying a sheet such as paper, and more particularly, to an improved sheet conveying apparatus for conveying a sheet using a sheet conveying body such as a conveying roll. About.

[0002]

2. Description of the Related Art Heretofore, as a sheet conveying apparatus, there has been widely known a sheet conveying apparatus in which a conveying roll for contacting a sheet such as a sheet is provided, and the roll is rotated to convey the sheet.

However, in this type of sheet conveying apparatus, the frictional resistance between the conveying roll and the sheet is reduced due to a prolonged use period, causing slippage, and causing a sheet conveyance failure. Issues were seen. This is because, for a long time, foreign substances such as paper dust adhere and accumulate on the surface of the transport roll, and the frictional resistance of the transport roll surface decreases to cause slippage.

In particular, in recent years, in a full-color image forming apparatus such as a full-color copying machine or the like, since a clear image having excellent coloring properties can be obtained, a coating layer (coating layer) containing a pigment is provided on a base material such as paper. However, when the coated paper is conveyed, if the pigment separated from the coating layer adheres to the conveyance roll, the frictional resistance of the conveyance roll surface will be significantly reduced. It is easy to occur.

As a means for solving such a technical problem, a cleaning roll is press-contacted to a transport roll, and the cleaning roll is rotated at a speed about 10% slower than the transport roll, so that foreign matter adhering to the transport roll is obtained. There has been proposed a technique for removing the noise (Japanese Patent Laid-Open No. 2-2334).
No. 31).

[0006]

However, in such a technical means, the provision is made only by providing a speed difference between the transport roll and the cleaning roll. There was a technical problem that the range was narrow and the degree of freedom in design was reduced.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned technical problems, and can easily ensure the cleaning performance of a sheet conveying member such as a conveying roll by adopting a new design method. It is intended to provide a sheet conveying device capable of performing the above.

[0008]

SUMMARY OF THE INVENTION The present inventor has developed a nip pressure acting between a sheet conveying member and a cleaning roll, and a force applied in a tangential direction of a nip portion between the sheet conveying member and the cleaning roll (hereinafter referred to as a tangential force). In the correlation between the coefficient of friction between the sheet conveying member and the cleaning roll, it was found that there was a region where good cleaning performance could be obtained, and the allowable range was determined by experiments. This has led to the invention of the present invention.

That is, according to the present invention, as shown in FIGS. 1 (a) and 1 (b), a sheet conveying body 1 which comes into contact with a sheet S and conveys the sheet S, and is arranged in pressure contact with the sheet conveying body 1, In a sheet transporting apparatus including a cleaning roll 2 for cleaning the sheet transporting body 1 following the rotation of the sheet transporting body 1, a nip pressure F _N applied to a nip portion N between the sheet transporting body 1 and the cleaning roll 2 is provided. (N) and the tangential load F _L (N) of the tangential force F _T (N) applied to the nip portion N in the tangential direction of the cleaning roll 2 in the direction opposite to the moving direction of the cleaning roll 2. When the friction coefficient mu _a between the seat carrier 1 and the cleaning roller 2 and is characterized by satisfying the relational expression F _L <μ _a F _N.

Further, according to the present invention, the nip pressure F
_N (N) satisfies the relational expression of F _N ≧ 0.392.

Further, the present invention provides the nip pressure F
_N (N) satisfies the relational expression of F _N ≦ 3.92.

In FIG. 1B, F _T = F _B = kF
_The straight line of _N is described, which corresponds to the nip pressure F _N
Proportional braking force of the cleaning roll 2 to increase in F _B to indicate the (tangential load F _L to be described later). Note that the symbol k is a constant.

In such technical means, the sheet conveying device according to the present invention is not limited to the sheet conveying device provided in the conveying path of the sheet S,
Sheet feeding device (so-called sheet feeding device or sheet feeding device) for feeding the sheet to the conveying path.

The shape of the sheet conveying member 1 may be appropriately selected such as a roll shape or a belt shape as long as the sheet conveying member 1 comes in contact with the sheet S and conveys the sheet S. The sheet transport body 1 includes not only a sheet S provided for transporting the sheet S but also a component provided for supplying or feeding the sheet S.

Further, the cleaning roll 2 may be appropriately selected as long as it is disposed in pressure contact with the sheet transporting body 1 and rotates following the rotation of the sheet transporting body 1. From the viewpoint of securing, it is preferable to be composed of urethane foam.

Furthermore, the tangential load F _L, although smaller from the viewpoint of ensuring smooth rotation of the cleaning roller 2 is preferred, large to some degree is preferred from the viewpoint of securing the cleaning performance. Here, as described above, the cleaning roll 2, such as but braking force F _B which increases in proportion to the nip pressure F _N is such of, insufficient tangential load F _L In this braking force F _B in the embodiment, from the viewpoint of ensuring tangential load F _L of the required amount, preferably brake means for increasing the tangential load F _L is provided on the cleaning roll 2.

Further, in a mode in which a driving source for rotating the cleaning roll 2 is provided, the sheet S
A sheet conveying body 1 for conveying the sheet S in contact with
A cleaning roll 2 for cleaning the sheet conveying member 1, which is disposed in pressure contact with the sheet conveying member 1 and is driven to rotate in the same direction as the sheet conveying member 1 in the nip portion N; and according to the section N nip pressure F _N (N), the tangential driving force exerted on the moving direction of the cleaning roller 2 of the tangential force exerted on the tangential cleaning roller 2 F _T (N) of the nip N F _D (N) and the coefficient of friction μ _a between the sheet conveying member 1 and the cleaning roll 2 satisfy the relational expression of F _D ≦ μ _a F _N , and the tangential driving force F
_D and (N), said tangential force F _T tangential load according to the direction opposite to the said tangential driving force F _D of the (N) (N) F _L
(N) preferably satisfies the relational expression of F _D > F _L.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail based on an embodiment shown in the accompanying drawings. First Embodiment FIG. 2 shows a schematic configuration of a sheet conveying apparatus to which the present invention is applied. In the present embodiment, the sheet conveying device is used as a sheet feeding device of, for example, a monochrome image forming apparatus or a full-color image forming apparatus. P is conveyed to, for example, an image transfer unit (not shown) via a conveyance chute 30 which is a paper conveyance path.

In this embodiment, the paper supply device 10
Is a sheet tray 11 on which sheets P as sheets are placed.
A nudger roll 12 for taking out the paper P placed in the paper tray 11, a feed roll 13 for sending the paper P taken out of the paper tray 11 to the transport chute 30 side, and a press-contact arrangement with the feed roll 13. And a retard roll 14 to be provided. Here, in the present embodiment, the surfaces of the nadger roll 12, the feed roll 13, and the retard roll 14 are each made of a rubber material such as EPDM. Also, retard roll 14
Is provided with a torque limiter (not shown). Accordingly, when only one sheet of paper P is transported between the feed roll 13 and the retard roll 14, the retard roll 14 transports the feed chute 30 together with the feed roll 13 using the idling torque of the torque limiter. When a plurality of sheets P are conveyed between the feed roll 13 and the retard roll 14, the sheet P in contact with the retard roll 14 is moved toward the sheet tray 11. And rotate in the direction to return. Therefore, when the papers P are multiplexed, the multiplexed papers P are separated and conveyed one by one. Note that the retard roll 14 may be of a type that does not rotate in the direction in which the paper P in contact with the retard roll 14 is returned to the paper tray 11 side and remains stationary.

Further, an arc-shaped paper guide 1 for guiding the paper P to the transport chute 30 is provided at the outlet side in the paper transport direction when viewed from the pressure contact portion between the feed roll 13 and the retard roll 14.
6 are provided. In the present embodiment, the cleaning roll 15 is arranged in contact with the feed roll 13. Further, reference numeral 18 denotes a motor for rotating the feed roll 13 so as to rotate the feed roll 13 in the paper transport direction.

The transport chute 30 serving as a paper transport path is provided with a pair of rolls 20 (21, 2) as transport rolls.
2) is provided. Here, the surface of the roll 21 is E
A rubber roll made of a rubber material such as PDM,
The roll 22 is a facing roll whose surface is made of a resin material.

Next, the cleaning roll 15 according to the present embodiment will be described in detail. In the present embodiment, the cleaning roll 15 is made of urethane foam and has a hardness of 20 degrees (Asuka C). Here, the hardness of the feed roll 13 to be cleaned is 3
This is 0 degree (JISA), whereby the feed roll 13 bites into the cleaning roll 15 and the contact area between them can be increased.

Further, the cleaning roll 15 has a hollow shape, and a shaft 15a is disposed through the hollow portion as shown in FIG. Here, the shaft 15a is fixedly disposed on a first protruding portion 41a of a mounting plate 41 of the urging mechanism 40 described later, and when the cleaning roll 15 rotates, the shaft 15a and the hollow portion surface of the cleaning roll 15 are in contact with each other. It is driven and rotated while rubbing.

In the present embodiment, the urging mechanism 40 for urging the cleaning roll 15 toward the feed roll 13 includes a mounting plate 41 on which the cleaning roll 15 is mounted, and a supporting portion 43 for supporting the mounting plate 41.
And a base 45 to which the support portion 43 is fixed. First, the mounting plate 41 includes a main body portion 41c and a first protruding portion 41a having a substantially L-shaped cross section, and a second protruding portion 41b protruding from a substantially central portion of the main body portion 41c in parallel with the first protruding portion 41a. have. A shaft 42 is provided between the distal end of the second projecting portion 41b and the distal end of the supporting portion 43 attached to the fixed base 45. Is swingable about a shaft 42. Further, a contraction spring 44 is disposed between the base plate 45 and one end of the main body portion 41c of the mounting plate 41, whereby the cleaning roll 15 is urged toward the feed roll 13. Is to be done. This urging force will be described later. In the present embodiment, the feed roll 13 and the cleaning roll 1
5, the center A of the nip N and the center B of the shaft 42 are located on the same horizontal height Z, so that the nip pressure F _{N at the} nip N varies depending on the position. Is constant. The diameter of the code D _R is the cleaning roll 15, D _S represents the diameter of the shaft 15a.

Next, the urging force of the cleaning roll 15 against the feed roll 13, that is, the nip pressure F _N
Will be described. FIG. 4 schematically shows the force acting between the feed roll 13 and the cleaning roll 15 during cleaning. Where the sign μ
_a coefficient of friction between the feed roller 13 and the cleaning roll 15, the coefficient of friction between the mu _b is a cleaning roll 15 shaft 15a, F _T feed rolls 13
And a force acting in a tangential direction of a nip portion N between the cleaning roller 15 and the cleaning roll 15 (hereinafter, referred to as a tangential force).

Then, the nip pressure F _N and the tangential force F _T
Is selected from the range surrounded by the straight line L ₁ ~L ₄ shown in FIG. Here, L ₁ : F _T = F _D = μ _a F _N (N) (1) L ₂ : F _T = F _L = F _B = jμ _b F _N = (D _S / D _R ) μ _b F _{N (N) ... (2)} L 3: F N = 0.392 (N) ... (3) L 4: a _{F N = 3.92 (N) ...} (4).

[0027] First, a description will be given of the straight line L _1. Straight line L ₁
Is a tangential force F _T (tangential driving force F _D ) applied by the feed roll 13, and when a load (tangential load F _L ) greater than this is applied, the cleaning roll 15
Will not rotate, and the local wear of the cleaning roll 15 will increase. Accordingly, the tangential load F _L is selected the load from the area to be the straight line L less than _1.

The straight line L ₂ is the line of the cleaning roll 1.
The frictional force acting between the shaft 5 and the shaft 15a is converted into a force acting on the outer peripheral surface of the cleaning roll 15. Therefore, under the condition that the cleaning roll 15 is driven to rotate with the rotation of the feed roll 13, the tangential force F _T
But the fact that is automatically set to the tangential driving force F _D> tangential load F _L.

Further, a straight line L ₃ is the lower limit of the nip pressure F _N required for obtaining the cleaning effect.
The straight line L ₄ is the feed roll 13 or the cleaning roll 1
5 or the like which is the upper limit of the nip pressure F _N for not use excessive force.

Next, the operation of the sheet conveying apparatus according to this embodiment will be described. Now, when the paper P is fed and transported from the paper supply device 10, as shown in FIG. 2, the paper P placed on the paper tray 11 is fed by the nudger roll 12 to the feed roll 13 and the retard roll. 14 to the pressure contact side. Then, only one sheet of paper P passes through the pressure contact position by the action of the retard roll 14 and is sent to the transport chute 30 via the paper guide 16 and the transport roll pair 20. Thereafter, the sheet P is transported to an image transfer unit (not shown).

At this time, the cleaning roll 15 rotates following the rotation of the feed roll 13 and removes foreign matters adhering to the feed roll 13. Here, the nip pressure F _N of the cleaning roll 15, because it is selected from a range above, with a simple configuration, while preventing even wear of the cleaning roll 15, it is possible to obtain sufficient cleaning performance. Also, basically, the nip pressure F _N
Cleaning performance can be managed only by
There is also an advantage that the design becomes easy. Here, if focus on cleaning performance selects the nip pressure F _N increases, whereas, it is sufficient to select a nip pressure F _N smaller if emphasizing wear resistance. However, nip pressure F
_{Even if N} is set small, the cleaning roll 15
Because but sometimes become worn, it is preferable to set the nip pressure F _N and tangential force F _T in consideration of the wear resistance of the cleaning roll 15.

Further, in this embodiment, since the cleaning roll 15 is made of urethane foam which is softer than the feed roll 13 to be cleaned, the contact area between them can be increased. Since there is a foam portion (void portion), the removed foreign matter can be taken into the urethane foam.

Embodiment 2 The present embodiment is substantially the same as Embodiment 1 except that FIG.
As shown in FIG. 6, a cleaning roll 15 is arranged as a brake means so as to be skewed with respect to the feed roll 13, so that it can be used as a brake means. Note that, of the components of the sheet conveying device according to the present embodiment, the same components as those of the sheet conveying device according to the first embodiment are denoted by the same reference numerals as those in the first embodiment, and the detailed description thereof will be given here. Description is omitted.

In this embodiment, the base 45 is swingable about the axis Y as shown in FIG. 3, so that the cleaning roll 15 is 13 is skewed. In FIG. 6, reference numerals 13a and 13b denote divided rolls, and reference numeral 13c denotes the rolls 13a and 13b.
Are shown.

As described above, when the cleaning roll 15 is disposed obliquely with respect to the feed roll 13, when the feed roll 13 rotates, the cleaning roll 15 acts as a braking means, that is, a rotation resistance (braking force). Thus, in this embodiment, as shown in FIG. 5, the straight line L ₂
Is a straight line L ₂ 'L ₂ ' taking into account the rotational resistance F _R : F _L = F _B + F _R = (D _S / D _R ) μ _b F _N + F _R (N) (5)

[0036] In this embodiment, by increasing the rotation resistance force F _R, since increasing the tangential load F _L, it is possible to increase the frictional force between the feed roller 13 and the cleaning roll 15, As a result, the cleaning performance can be improved.

The method of applying the braking force to the cleaning roll 15 is not limited to the above-described method, but may be a method of attaching a torque limiter to the cleaning roll 15.

In the first and second embodiments, an example in which the above-described design method is applied to the cleaning roll 15 of the feed roll 13 has been described. However, the present invention is not limited to this. In the case where a cleaning roll is provided on the rubber roll 21 of the roll pair 20, or in the case where a cleaning roll is provided on the nudger roll 12, the above-described design method may be applied to these cleaning rolls. Good.

[0039]

As described above, according to the present invention,
The nip pressure acting between the sheet conveying member and the cleaning roll, the force applied in the tangential direction of the nip portion between the sheet conveying member and the cleaning roll (tangential force), and the coefficient of friction between the sheet conveying member and the cleaning roll By properly selecting the correlation, good cleaning performance can be obtained with a simple design technique.

[Brief description of the drawings]

FIGS. 1A and 1B are explanatory views showing an outline of a sheet conveying apparatus according to the present invention.

FIG. 2 is a first embodiment of a sheet conveying apparatus according to the present invention.
FIG. 2 is an explanatory diagram showing a schematic configuration of the device.

FIG. 3 is an explanatory view schematically showing a cleaning device of the sheet conveying device.

FIG. 4 is a schematic diagram showing a correlation between a feed roll and a cleaning roll.

FIG. 5 is an explanatory diagram showing a correlation between a nip pressure and a tangential force. 5 is a flowchart relating to cleaning of the sheet conveying device according to the first embodiment.

FIG. 6 is a schematic diagram illustrating a correlation between a feed roll and a cleaning roll according to Embodiment 2.

[Explanation of symbols]

 1: sheet transporter, 2: cleaning roll, N: ni
Group, S ... sheet, F _N... nip pressure, F_T… Tangential direction
Force, F_D… Tangential driving force, F_L… Tangential load, F_B…
Braking force, 10: paper supply device, 11: paper tray,
12 ... nadger roll, 13 ... feed roll, 14 ...
Retard roll, 15 ... for cleaning roll, 16 ...
Paper guide, 18 motor, 20 roll pair, 30 transport
Chute, 40 ... biasing mechanism

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hajime Yui 2274 Hongo, Ebina-shi, Kanagawa Prefecture Inside Fuji Xerox Co., Ltd. (72) Inventor Masayuki Nagata 2274 Hongo, Ebina-shi, Kanagawa Prefecture Fuji Xerox Co., Ltd.F-term ( Reference) 3F101 AB07 LA02 LB03

Claims (6)

[Claims] 1. A sheet conveying body that comes into contact with a sheet and conveys the sheet, and a cleaning roll that is arranged in pressure contact with the sheet conveying body and that rotates by the sheet conveying body to clean the sheet conveying body. In the sheet transport device, a nip pressure F _N (N) applied to a nip portion between the sheet transport body and the cleaning roll, and a tangential force F applied to a tangential direction of the cleaning roll at the nip portion.
_The tangential load F _L (N) of _T (N) acting in the direction opposite to the direction of movement of the cleaning roll, and the coefficient of friction μ _a between the sheet conveying body and the cleaning roll.
DOO is, the sheet conveying apparatus characterized by satisfying the relational expression F _L <μ _a F _N. 2. The sheet conveying apparatus according to claim 1, wherein the nip pressure F _N (N) satisfies a relational expression of F _N ≧ 0.392. 3. The sheet conveying apparatus according to claim 1, wherein the nip pressure F _N (N) satisfies a relational expression of F _N ≦ 3.92. 4. A sheet conveying device according to claim 1, said cleaning roll, the sheet conveying apparatus characterized by brake means for increasing the tangential load F _L is provided. 5. The sheet conveying device according to claim 1, wherein the cleaning roll is made of urethane foam. 6. A sheet transporting body that comes into contact with a sheet and transports the sheet; and a sheet transporting body that is disposed in pressure contact with the sheet transporting body and is rotationally driven in the nip portion in the same direction as the sheet transporting body. A cleaning roll for cleaning the nip portion, wherein a nip pressure F _N (N) applied to the nip portion and a tangential force F _T (N) applied to a tangential direction of the cleaning roll at the nip portion correspond to the nip pressure F _N (N). The tangential driving force F _D (N) acting in the direction of movement of the cleaning roll, and the coefficient of friction μ between the sheet conveying body and the cleaning roll
_a satisfies the relational expression of F _D ≦ μ _a F _N and the tangential driving force F
_D and (N), said tangential force F _T tangential load according to the direction opposite to the said tangential driving force F _D of the (N) (N) F _L
(N) and the sheet conveying apparatus, characterized by satisfying the relational expression F _D> F _L.