JPH01209256A - Web conveyer - Google Patents

Abstract

PURPOSE:To enable stable further smooth conveyance to be attained by providing a gas resisting object in parallel with a direction of web width in a web introducing part to a guide surface and its guide out part or in both these parts. CONSTITUTION:A web 2 is floated and inverted running in a direction of arrow head along a guide surface 1 of arc-shaped side section having many jet holes 6 jetting gas. A gas resisting object 7 is provided in parallel with a width direction of the web 2 in an introducing part 4 to the guide surface 1 and/or in its guide out part 5. A flow of gas in its diffusing part from the guide surface enables the generation of vibration of the web to be extremely suppressed from a high frequency over a low frequency by providing the object 7 in the width direction serving as the resistance object for the gas escaping in an advancing direction of the web.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an apparatus for floating and conveying a continuously running flexible long strip support (hereinafter referred to as a "web").

[Prior art 1] In a web conveying device that levitates and conveys a web along a guide surface having a gas jetting hole or jetting slit, the side section of the guide surface is arcuate, and the web also floats along the guide surface. A web conveying device that travels in reverse in an arc along a web is conventionally known.

The above web conveying device can run stably when the cross-sectional shape is large and the web tension is low, but when the cross-sectional shape is small and the web tension is high, the web and guide surface are It is necessary to increase the pressure of the gas that acts as a cushion between the web and the guide surface. tends to be relatively large, and in such a case, when the pressure of the high-pressure gas mentioned above is rapidly released and lowered at the guide surface introduction and outlet sections of the web, large fluctuations occur in the web. However, as a result, the flying height fluctuates, and there is a possibility that the web will come into contact with the guide surface.

As a measure to prevent this flapping, Japanese Patent Laid-Open No. 60-9305
No. 6 discloses a method of providing a guide plate extending along a guide surface in the traveling direction of the web. Although this method does reduce the fluttering, the pressure of the fluid between the guide plate and the web in the guide plate portion decreases, and the flying height of the web decreases. Therefore, if the web has properties such as curling, there is a risk of contact between the web and the guide plate.

Also, JP-A-62-! No. 67162 discloses a method of providing a plurality of rectifying plates parallel to the direction of travel of the web and perpendicular to the web surface at the introduction and exit portions of the web to the guide surface of the web.

However, all of these methods suppress flapping by rectifying the exhaust air, but the method using the rectifying effect described above may not be able to sufficiently prevent flapping depending on conditions such as the cross-sectional shape of the device and the tension of the web. , and the flying height is also unstable.

In the case of conveying a web, for example, in the production of photosensitive materials, particularly in the case of conveyance immediately before and after the coating process, very strict stability of conveyance is required, and conventional floating conveyance devices cannot be used.

[Problems to be Solved by the Invention] In order to solve the above-mentioned problems, an object of the present invention is to provide a web conveying device that can handle a wide range of conveying conditions, such as device size, web tension, web film thickness, and web conveyance conditions. It is an object of the present invention to provide a web conveying device that does not itself become a vibration source of the web due to its rigidity and enables stable and smooth conveyance. Furthermore, it is an object of the present invention to provide a conveyance device that can be applied to cases where strict conveyance stability is required, such as when coating photosensitive materials.

[Means for Solving the Problems] The above-mentioned object of the present invention is to provide a web conveyance device that levitates and conveys a web along a kite surface having a jet hole or a jet slint that spouts out gas, and in which the web is conveyed while floating. It has been found that this can be achieved by a web conveying device characterized in that a gas resistor is provided in the web introduction part and the lead-out part in parallel to the width direction of the web.

The present invention will be explained in more detail below.

P is the gas supply pressure within the guide surface (hereinafter the gas ejection device that makes up the guide surface is referred to as a reverser), P2 is the average static pressure between the web and the guide surface, r is the radius of the arc of the guide surface, and web tension is T1 The porosity expressed by the following formula is p.

P2 is proportional to T and inversely proportional to r. In addition, the flying height of the web relative to the guide surface is determined by the amount of air between the web and the guide surface,
In other words, it is proportional to the product of the air flow to the reverser and the open area p. As mentioned above, in the conventional thinking, in order to avoid contact between the web and the guide surface, r should be relatively large and the flying height should also be relatively large. Therefore, conditions were often adopted in which the porosity p was large, the air volume was large, and the supply pressure P1 was small. Therefore, P 1/P
The ratio of z is small, and when the web tension fluctuates in such a system, P2 fluctuates, but since P□/P2 is small, the fluctuation cannot be absorbed, and instead results in a fluctuation in the flying height.

In the present invention, the flying height is made smaller than in the prior art. Therefore, the porosity p can be reduced, and the supply to the reverser can also be reduced compared to before.

As a result, PI/P2 can be increased, and fluctuations in P2 due to fluctuations in web tension can also be absorbed.

However, even with this type of system, although it is effective in stabilizing the flying height, the velocity of the jet air toward the web is faster than that of the reverser, so when looking at the frequency components of web vibration, vibrations with high frequency components occur. I understand. It has been found that the present invention is also effective in suppressing such vibrations.

Preferred embodiments of the present invention will be described below.

FIG. 1(a) is a perspective view showing an example of the present invention, and FIGS. 1(b) to 1(e) are sectional views. In the same figure (a), the web 2 floats along the arc-shaped guide surface 1 having a side cross-sectional shape having a large number of gas jetting holes 6, and travels reversely in the direction of the arrow. A gas resistor 7 is provided parallel to the width direction of the web 2 at the introduction part 4 and/or the lead-out part 5 to the guide surface l.60 From various experiments, the inventors have found that the gas is diffused from the guide surface. By paying attention to the flow in the part where the web moves, and installing something on the width that acts as a resistance against the gas escaping in the direction of web travel, we discovered that it is possible to extremely suppress the occurrence of web vibration from high to low frequencies. did.

This was achieved by suppressing the exhaust of gas in the web traveling direction and bringing the inside of the guide surface closer to a sealed system (#normal system). Furthermore, by making the porosity smaller in the present invention, the static pressure (cushion pressure) between the layer guide surface and the web is stabilized, and an extremely rigid air layer is formed. There was almost no change in the amount of float. In addition, by providing a gas resistor, the static pressure between the guide surface and the web surface tends to be uniform across the width of the web.
It is also good against the occurrence of "wrinkles" that occur parallel to the direction of web travel, and is extremely stable when transporting thin film webs.

In addition, the shape of the gas resistor as mentioned above is triangular, square,
It can be any shape such as semicircle, circle, polygon, etc.
It doesn't matter how big or small it is.

Even if the web is not uniform and there are cuts in it, the effect is still there.

Further, the distance between the gas resistor and the web refers to the distance between the resistor and the web, which is a gap through which gas can pass, and is indicated by h in FIG. 1(d). This distance is preferably as small as possible as long as there is no contact, and is preferably 3 mm or less.

The material of the gas resistor is not particularly limited. Examples include metals, plastics, and elastic bodies such as AQ gold alloy and rubber.

In the present invention, the overall effect is greater by reducing the porosity of the gas ejection part and increasing the supply pressure to the reverser.The pores may have any shape, but are usually circular or slit-shaped. The area of each pore used is preferably small, and the porosity is preferably 1% or less. In addition, the cross-sectional shape of the opening should be changed to a pocket in the cross-sectional shape as shown in Figure 2, when there is a risk that the coated surface may be blown unevenly by the ejected gas, such as when this device is installed immediately after coating. By providing this, it is possible to suppress the ejection speed and prevent the occurrence of unevenness.

The arc radius of the cross-sectional shape of the guide surface is preferably 100 mm.
= 1000mm. The holding angle θ of this device is preferably 90° or more, but even if it is less than that, the effects of the present invention are significant. In the case of Fig. 1(a), it is 180°, and in the case of Fig. 1(e)
) is 906.

Adjustment of the distance between the gas resistor and the web If the cross-sectional shape of the parser device is circular as shown in Figure 1(b), the size and attachment of the resistor can be adjusted by position. ) in the case of a hanging bell shape, the only adjustment is the size. In the case of a circular shape, the attachment positions are preferably at the introduction part before the web is held against the beam parser, and at the outlet part after the web.

The larger the free span Q, which is the distance to the guide roll in the tangential direction of the guide surface of the web in Fig. 1 (a), can suppress the generation of high-frequency component web vibrations, but in the case of thin webs, it is too large. If it is removed, wrinkles that naturally occur due to the flatness of the web will become larger, so it is preferably about 300 to 2000 mm.

Figures 3(a) and 3(b) are 7° cross-sectional views of the gas resistance object (flange) in the width direction of the web. A so-called "flange" which increases the flying height at the width end of the web may also be used.This "flange" may not cover the entire arc of the guide surface of the web holding portion, but may have a notch, for example.

Webs used in the present invention include paper, plastic film, metal, resin coated paper, synthetic paper, and the like.

The present invention is particularly suitable as a production apparatus for photographic light-sensitive materials, and can be suitably applied to a floating coating backup roll for coating light-sensitive materials in which web vibration must be extremely suppressed.

[Example] EXAMPLES The effects of the present invention will be specifically explained below with reference to Examples.

Example-1 FIG. 4 is a sectional view of the apparatus used in this example. FIG. 6(a) shows the case where the rectifying plate 3 described in the above-mentioned Japanese Patent Application Laid-open No. 60-93056 is used, and FIG. 2(b) shows the position when the gas resistor of the present invention is provided. Further, FIG. 5 is a perspective view of the apparatus in which the rectifying plate 3' described in the above-mentioned Japanese Patent Application Laid-Open No. 62-16716 is installed.

A polyethylene terephthalate film base with a thickness of 100 μm and a width of 1000 mm was used as the web, and the conveyance system was set at a web tension of 15 kg/m, a conveyance speed of 40 m/min, and a wrap angle of θ of 180 degrees and an arc radius of r of 200 mm. ) Use port 3) Use the present invention (Figure 4 b) 7 C) Use rectifier plate (Figure 5) 3' Under the conditions (a) to (c) above, further use the following (a) and (b).
).

(a) Open area ratio 2.0% (Nozzle hole diameter 5, Omm) (b) Open area ratio 0.4% (Nozzle hole diameter 1.0 + n + o) Web in the direction of change in flying height at the position indicated by the arrow in Figure 4 The intensity of vibration was measured with a laser displacement meter and further evaluated by frequency analysis.

The results are shown in Table-1.

Table 1 As is clear from the results in Table 1, it was possible to suppress the occurrence of web vibration under the conditions of the mouth according to the present invention. In particular, under the conditions of the example, high-frequency vibrations were suppressed, and it was possible to transport the web without causing it to become a source of web vibration.

Example-2 FIG. 6 is a schematic cross-sectional view of one example of a coating device.

For example, in coating a photosensitive material, an example will be shown in which a roll having gas ejection holes in the backing roll and having the gas resistor of the present invention is used.

In FIG. 6, the web 2 is conveyed in a non-contact manner while being held by a gas jet hole 6 and a gas jet device 11 having a gas resistor, during which a coating liquid such as a gelatin liquid such as a photosensitive material is applied by a slide hopper coating machine 10. and then enters the cooling zone.

The gas ejector has an aperture diameter of 0.1 mm (round hole), a roll outer surface radius of 130 mm, an average aperture area ratio of 0.04%,
The supply air pressure (gauge pressure) was 1000 mmaq.

At this time, the maximum static pressure between the base and the gas outlet hole was measured to be approximately 110 mmaq.

Using the above apparatus, the following coating liquid was applied onto a polyethylene terephthalate film base having a thickness of 175 μm and a width of 1000 mm at a coating speed of 40 m/min and a coating tension of 15 kg/width.

Upper coated layer: Gelatin aqueous solution for protective film (film thickness 20 μm) Lower layer: Silver halide emulsion for X-rays using gelatin as a binder (film thickness 60 μm) Next, slit plate 1 in the cold air zone
From No. 4, cold air at approximately 5° C. was blown onto the coated surface to form a gel and then dry.

The conditions were as follows.

A) When nothing is attached to the gas ejector Port) When a rectifying plate (Fig. 4 a) is attached C) When a gas resistor of the present invention is attached (h is about 1 mm)
The results are shown in Table-2.

Table 2 ☆ () indicates when h is set to 3. From the results in Table 2, there is no coating failure in the case of the present invention.
It can be seen that this method can be effectively applied to the coating of harsh photosensitive materials.

[Effects of the Invention] According to the present invention, the web conveyance device can handle a wide range of conveyance conditions, such as the size of the device, the tension of the web, the thickness of the web,
It has been possible to provide a web conveying device that does not itself become a source of web vibration due to the rigidity of the web and enables stable and smooth conveyance. Further, according to the present invention, it was possible to provide a web conveying device that can be effectively applied as a non-contact backup roll in coating, for example, coating photosensitive materials.

[Brief explanation of the drawing]

FIG. 1(a) is a perspective view showing an example of the present invention, and the same figure (bXcXdXe) is a sectional view. Fig. 2 is a sectional view showing an example of the form of the ejection hole, Fig. 3 is a sectional view of an example of application to the width, and Figs. FIG. 4(b) is a perspective view, FIG. 4(b) is a cross-sectional view in which a gas resistor is provided, and FIG. 6 is a cross-sectional view showing an example used in a coating device. 1 Guide surface 2: Web 3. 3': Straightening plate 4: Web introduction section 5: Web lead-out section
6: Ejection hole 7.7' Two-fluid resistance object 8 Two-way stroke R Two-fluid resistance object 8 Circle radius of guide surface θ: Embracing angle h: Distance to Niranib resistance object Q: Distance of free span 15: Cooling zone

Claims (2)

[Claims] (1) A web conveying device that levitates and conveys the web along a guide surface that has gas jetting holes or jetting slits, and the width of the web is A web conveying device characterized by providing a gas resistor parallel to the direction. (2) The web conveying device according to claim 1, wherein the distance between the gas resistor and the web is set at 3 mm or less.