JP2698926B2 - Web tension control device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a web tension controller for controlling the tension of a single-side coated web during continuous conveyance.

[Conventional technology]

Immediately after the photoreceptor has been applied to one side, the web (long photoreceptor material) has its application surface floated and supported by the gas jetting cylinder, and its back surface (dry surface) contacted and supported by the transport rollers, and is continuously high-speed. Conveyed. The web tension controller is a device that adjusts the web tension, which changes according to the load fluctuation of the transport system, within an appropriate range during the continuous transport. Conventionally, this web tension control device is configured by providing a dancer roll for finely adjusting the web transport speed at an appropriate position in a web traveling system.

For example, the apparatus A shown in FIG. 3 includes two guide rolls 12 and 12 ′ that contact and support the back surface 11 b of the web 11 and a dancer roll 13 that can swing in a direction perpendicular to a line connecting the centers of the two rolls. It comprises a gas ejection tube 14, and the web 11
The application surface 11a of the web 11 is floated and supported, and the tension of the web 11 can be adjusted.

The apparatus B shown in FIG. 4 comprises two gas jetting cylinders 22 and 22 'for supporting the coating surface 21a of the web 21 in a floating manner, and the web 21
The back surface 21b of the jetting cylinder 22 and 22 '
This device is provided with a dancer roll 23 that can swing in a direction perpendicular to a line connecting the centers of the two, and the web tension can be controlled by swinging the dancer roll 23 by a predetermined angle.

[Problems to be solved by the invention]

In the conventional web tension control devices described above, it is difficult to control the tension while keeping the running state of the web stable in any of the devices A and B.

That is, in the case of the apparatus A (FIG. 3), the response is poor because the structure is complicated and the dancer roll itself is connected to the air duct, and it is not possible to follow the high-speed fluctuation of the web floating support state. Further, in the case of the apparatus B (FIG. 4), although the response is relatively good, the web is swung left and right with respect to the traveling direction or the vibration is reduced because the web floating amount with respect to the holding surface of the jetting cylinder is large. There is a problem that precise tension control becomes difficult due to easy occurrence of the tension.

In view of the above, it is a second object of the present invention to prevent the occurrence of vibration due to fluctuations in the hugging angle by preventing the hugging angle of the web hugging surface from changing even when the dancer roll position changes.

[Means for solving the problem]

In order to solve the above-described problems, the present invention provides two gas ejection tubes that levitate and support a continuously running web, a line that supports and supports the web between the two ejection tubes, and connects the centers of the ejection tubes. A dancer roll capable of swinging in a direction perpendicular to the web tension control device, wherein a guide roll for maintaining a holding angle of a web holding surface of each jetting cylinder constant regardless of a position of the dancer roll, It is provided between the dancer roll and the two jetting cylinders, respectively, so as to prevent generation of vibration due to a change in the embracing angle accompanying the movement of the dancer roll.

〔Example〕

Hereinafter, the present invention will be described with reference to an embodiment shown in FIGS.

FIG. 1 is a plan view showing the overall configuration of the web tension control device of the present invention, and FIG. 2 is a perspective view showing the configuration of a gas ejection tube.

In the drawing, reference numeral 1 denotes a web continuously running in a main body H of the web tension control device of the present invention. The web 1 is coated with a photographic photoreceptor material on a coating surface 1a and is transported in an undried state. Opposite side of application surface 1a (hereinafter referred to as back side)
In 1b, the photoconductor material is not applied, or even if it is applied, it is sufficiently dried, so that even if various rollers are brought into contact, the applied layer is not affected.

Reference numerals 2 and 2 'denote plastic gas jetting cylinders. The jetting cylinders 2 and 2' are configured so that the web 1 can be floated and supported by web holding surfaces 3, 3 'on their respective surfaces. That is,
The web holding surfaces 3, 3 'are provided with a large number of minute ejection holes F, and high-pressure gas in the ejection cylinders 2, 2' is ejected from the ejection holes F toward the coating surface 1a of the web 1, whereby The web 1 is supported by the static pressure of the air film interposed between the web 1 and the holding surfaces 3, 3 '. Here porosity K (ratio of sum S ₁ of the opening areas of = ejection holes F occupies the area S ₂ of the web Hugging surface 3 (or 3 ')) is made significantly smaller than the porosity of the conventional apparatus K = 2% or less,
Desirably, it is 1% or less. The opening ratio K regulates the internal pressure P of the ejection cylinders 2 and 2 ', and particularly, K = 1%
In the following cases, the internal pressure P is P = 200 mmAq or more, which is several times higher than that of the conventional device. More preferably, the internal pressure P = 300m
It is desirable to select a value of mAq or more. Therefore, web 1
Can be configured to maintain the flying height of the holding surface 3, 3 ′ irrespective of the position of the dancer roll 5.
The ejection hole F may be, for example, an elliptical or triangular hole having a non-circular cross section, or may be a slit arranged in parallel with the generatrix of the ejection cylinders 2 and 2 '. Good.

Reference numeral 4 denotes a gas resistance rib. The rib 4 is provided with web introduction portions 3a and 3a 'and withdrawal portions 3b of the web holding surfaces 3 and 3' of the gas ejection tube 2.
3b '. The rib 4 has an inverted U-shaped cross section and is parallel to the generatrix direction of the ejection tube 2. Thus, after the gas ejected from the ejection hole F becomes an air film interposed between the holding surface 3 (or 3 ') and the web 1, it is discharged from the introduction portions 3a, 3a' and the ejection portions 3b, 3b '. When the air is blown, the exhaust air is rectified to prevent the occurrence of web vibration due to the turbulence of the air flow. The material of the gas resistance rib 4 may be an elastic body such as a metal, a plastic, an Al alloy, and rubber.

The dancer roll 5 is provided between the jetting cylinders 2 and 2 'so as to contact and support the back surface 1b of the web 1 and finely adjust the transport speed of the web 1. That is, the dancer roll 5 is supported by the fulcrum 6 according to the tension during traveling.
Swings in a direction perpendicular to the line connecting the centers of the ejection tubes 2, 2 '. Then, in accordance with the amount of movement, the drive roll is instructed to increase or decrease the speed (not shown), and has a function of immediately controlling the original tension. 7 is a balancer of the dancer roll 5.

Reference numeral 8 denotes a guide roll, and the guide roll 8 is provided between the dancer roll 5 and the gas jetting cylinders 2 and 2 ', respectively.
The web 1 is supported in contact. The roll 8 is used to make the holding angle θ of the web holding surfaces 3 and 3 ′ of the gas ejection cylinders 2 and 2 ′ constant regardless of the position of the dancer roll 5, and makes contact with the back surface 1 b of the web 1. The supporting and holding angle θ is configured to be larger than the holding angle when no guide roll is provided.

The web 1 which is continuously conveyed has the coating surface 1a floated and supported by the gas jetting cylinders 2 and 2 ', and the back surface 1b is contacted and supported by the dancer roll 5, and the web 1 is moved in accordance with the swing of the dancer roll 5. The web tension can be controlled by finely adjusting the transport speed. At this time, the web 1 is stably supported by the static pressure of the gas jetted from the jet holes F, and the web floating amount d with respect to the web holding surfaces 3, 3 'hardly changes. Further, the holding angle θ of the web holding surfaces 3, 3 ′ is fixed to a fixed angle determined by the position of the guide roll 8, and does not depend on the position of the dancer roll 5 that changes with the swing.

In general, the relationship between the web and the gas jetting cylinder for floating the web is such that the gas supply pressure is P ₁ , the average static pressure (cushion pressure) between the web and the web holding surface is P ₂ , and the radius of the holding surface is r.
Assuming that the web tension is T and the opening ratio is K, the static pressure P ₂ is the tension T
And inversely proportional to the radius r. The flying height d of the web with respect to the holding surface is proportional to the amount of air flowing between the web and the holding surface, that is, the amount of air V to the ejection tube and the opening ratio K. Then, in order to avoid contact between the web and the holding surface, there is an idea that it is preferable to increase the radius r of the holding surface and increase the flying height d. In this case, taking a large opening ratio K (e.g. 5% or more), large air volume V, the supply pressure P ₁ is often relatively small. As a result, the ratio of the supply pressure to the average static pressure = P ₁ / P ₂ becomes smaller. However, in such a system, when P ₂ changes according to the fluctuation of the web tension T,
This change cannot be absorbed by P ₁ / P ₂ , resulting in a change in the flying height d.

Therefore, in the present invention, to reduce the flying height d and 2mm or less, and P ₁ / P to a value of ₂ is increased, the ejection tube with the opening ratio K so that the supply pressure P _1, can be increased to jet tube The amount of air supplied to the chamber is reduced to stabilize the static pressure state.

By reducing the opening ratio of the web holding surface, the static pressure between the web and the web holding surface was stabilized, an extremely rigid air layer was formed, and the change in the flying height due to the change in the tension of the web was almost eliminated. Further, by providing the gas resistance ribs, the exhaust air in the web traveling direction can be rectified and the static pressure state can be prevented from being disturbed, so that the generation of the web vibration from a high frequency to a low frequency can be largely suppressed. In addition, since the rigidity of the web and the air layer on the web holding surface is high, "crews" that can be parallel to the traveling direction of the web are less likely to occur, and the web transport state is further stabilized.

〔Example〕

An experiment in which the web tension control apparatus of the present invention configured as described above is applied to a web manufacturing process, and the three points of meandering of the tension-following base vibration dancer roll are compared with the performance of the conventional apparatuses A and B described above. Was performed, good results as shown in Table 1 were obtained.

(Effects of the Invention) As described above, the present invention provides two gas ejection cylinders that levitate and support a continuously running web, a line that supports and supports the web between the two ejection cylinders, and connects the centers of the ejection cylinders. A dancer roll capable of swinging in a direction perpendicular to the web tension control device, wherein a guide roll for maintaining a holding angle of a web holding surface of each jetting cylinder constant regardless of a position of the dancer roll, Since it is provided between the dancer roll and the two ejection cylinders, the web holding angle of the ejection cylinder is always kept constant, and the occurrence of vibration due to the variation of the holding angle can be prevented.

As a result, the tension control in the web manufacturing process can be remarkably stabilized, and a remarkable effect can be achieved in improving productivity and quality.

[Brief description of the drawings]

FIG. 1 is a plan view showing the overall configuration of a web tension control device of the present invention, FIG. 2 is a perspective view showing the configuration of a gas ejection tube, and FIG. 3 is a conventional device A using a dancer roll composed of a gas ejection tube. FIG. 4 is a plan view of a conventional apparatus B provided with a contact type dancer roll between two gas jets. 1 Web 1a Application surface 1b Back surface 2 2 'Gas jetting cylinder 3, 3' Web holding surface (means) 3a, 3a 'Web introduction part 3b, 3b' Web Outgoing part 4 ... Gas resistance rib 5 ... Dancer roll 6 ... Support point 7 ... Balancer 8 ... Guide roll H ... Web tension control device body of the present invention F ... Ejection holes 11, 21 ... Web 11a, 21a: Application surface 11b, 21b: Back surface 12, 12 ': Guide roll 13, 23: Dancer roll 14, 22, 22': Gas ejection tube A, B: Conventional web tension control device body

Claims (1)

(57) [Claims] 1. Two gas ejection tubes for supporting a continuously running web in a floating manner, the webs being contacted and supported between the two ejection tubes, and swingable in a direction perpendicular to a line connecting the centers of the ejection tubes. In the web tension control device provided with a simple dancer roll, a guide roll that maintains the hug angle of the web holding surface of the gas ejection cylinder constant regardless of the position of the dancer roll is provided between the dancer roll and the two ejection cylinders. A web tension control device, which is provided between the web tension controllers.