EP2014376A2 - Curtain coating machine - Google Patents

Abstract

The coating machine has a head (1) and a width-setting device (9), consisting of a pair of adjustable edge guides (3), a pair of auxiliary guides (4) and a pair of dividing plates (5). The surfaces of the inner side of the edge guides, the inner side of the auxiliary guides and the inner side of the dividing plates, forms a single vertical guide surface.

Description

The present invention relates to a curtain coater for applying a liquid to pasty medium on a running paper, cardboard or other fibrous web, comprising a spaced from the fibrous web curtain head from which the application medium is discharged downwards, and comprising an inclined guide plate, which receives the dispensed from the curtain head application medium in the region of the upper edge of the slope of the guide plate and let down along the slope and wherein the application medium falls from a curtain guide on the surface of the web in the form of a single or multi-layer curtain.

Above all, printing paper for catalogs and coated paper, which is used, inter alia, for pressure-sensitive grades or thermal paper, is produced by applying a coating to the surface of the web (base paper) with a coating machine and then drying it. Machines that perform the coating of the strokes in this way are, as mentioned, called coaters. Conventional coating machines exist for example in so-called blade coaters. These are those coating machines that work with a small round rod, or an air knife as dosing. That is, in these known machines, the Nachdosiermethode is applied. In this case, the application medium is applied in a more than necessary amount (excess) on the web and then scraped off with a doctor element, such as a blade or a rod or blown off with an air knife (dosed). However, there are problems with the brushing by post-dosing, that by the Andrückkraft the squeegee or by the fluid pressure when applying the stroke
the web the coating medium (eg coating color) penetrates deep into the web, or that the maintenance costs are high due to the wear of doctor blade or rod.

Thereupon, in recent years, more and more curtain coating machines have been generally used in which the curtain layer is discharged from the curtain heads spaced apart from the substrate to be coated (chambers with nozzles for discharging the curtain layer), and thus the underlying web is coated. Curtain coaters have long been used for photographic paper, but because of the instability of the curtain layer due to the trapping of air, bubbles trapped in the paint at high speeds, or lack of mechanical accuracy, the paint was not stable so that it would be difficult to clean Practice were not used for paper making.

The curtain coater, in contrast to the conventional Nachdosiermethoden no wearing parts such as squeegees or rods, so that they have the advantages that the maintenance is simple, that the amount of coating can be adjusted easily and with high accuracy that the operability is good, the effect of Surface improvement for the top coat (contour coat) is high, etc.

When using this coating method, it is required that the web be coated with two or more coats. In such cases, two curtain heads are placed one behind the other at the top of the moving web. The bar is formed of two layers by allowing the dispensed curtain to descend to the top of the web.

With such a curtain-type coating machine, if the speed at which the web travels is low (e.g., 120 m / min) as in a film of photos, a coating of two

Layers normally formed, because there is no great difference in the transport speed between lowering the paint curtain and the transport speed of the film.

However, when this curtain-type coating machine is used for paper webs, the webs are transported at a high speed of 300 to 2000 m / min so that a large difference in speed results because the falling speed of the curtain is about 180 m / min. In such a case, the curtain forming the lower layer arrives wet on the dry surface of the web. The friction factor between the two is relatively large, the web surface is pulled uniformly, and normally as the first layer (lower layer), a uniform coating without unevenness is formed. However, if the curtain forming the upper layer is wet on the wet surface of the first layer coating, the friction factor therebetween will be low and slippage will occur. The surface of the coating of the first layer can not be pulled well, resulting in unevenness. It can also happen that the coating of the second layer (upper layer) does not form normally.

A coater has already been proposed by the applicant of the present invention and disclosed in NO. JP 2006-2496111 disclosed.

In the FIG. 5 this known invention is shown. FIG. 5 shows a part of the side view of the curtain coater. Shown with this Curtain coater to two layers with two curtain heads 1a, 1b are applied. The dashes ta, tb, which flow in the slits da, db, respectively output downward and are applied in order on the slope 2a. With their movement on the relevant slope 2a they are stacked in order,

whereby two layers form. The respective layers of application medium pass from a downward edge of the curtain guide 2b over the respective slope 2a as curtains ca, cb onto the surface of the web w. In this way, a paint having two layers, sa (lower layer), sb (upper layer) is formed on the surface of the transported web w. The arrow indicates the direction of movement of the web w.

In such a coating machine, there are also cases in which the width of the web w to be spread is changed. In such cases, the width of the coating medium stroke t, which is applied by the curtain head 1, must be changed in accordance with the width of the web w. In order to change the width of the stroke t outputted from the curtain head 1, a block is inserted on both sides of the slot d from which the application medium t flows inside the curtain head 1 in accordance with the discharge width.

If this is done, the machine must be stopped in order to change the insert. The stop reduces the productivity of the machine, and it also causes the slot or block to be replaced or the format element to be firmly seated and can not be removed. It would also be possible to use a sliding lid, for which the machine does not have to be stopped, but after long use, the lid is also fixed and can not be moved, so that the application medium emerges from the gap between slot d and cover.

This makes it technically difficult to insert the lid, especially since the width of the gap is 0.3 to 0.5 mm very small.

The invention is therefore based on the object to provide a curtain coater, which does not have the disadvantages of the prior art.

According to the invention the object of the invention with the characterizing features of claim 1 is achieved.

Accordingly, it is provided that there is a device for adjusting the order or application width, which consists of a pair of adjustable edge guides, a pair of auxiliary guides and a pair of dividing plates, wherein each of the surface of the inside of the edge guide, the surface of the inside of the auxiliary guide and the surface of the inside of the partition plate forms a uniform vertical guide surface for the curtain.

The present invention is particularly suitable for applying heat-sensitive layers. When the widths of the heat-sensitive layers are changed in concert with the web, the width of the line discharged from the curtain head for the heat-sensitive layer does not change. But this layer can be output over the entire width. The output is divided into a middle part and one part on both sides of the machine. With the middle part of the web is coated, whereas the two side parts are collected. Thereby, the technical difficulties in the case of changing widths of the bar output from the curtain head for the heat-sensitive layer can be solved. At the same time, the pull-in caused by the surface tension (narrowing of the width with simultaneous increase in thickness by this proportion) at the edges of the stroke is avoided.

It is very expedient if the edge guides abut each other on the side of the guide plate and extend downwards from the upper region of the guide plate, the inner sides of the edge guides being parallel to one another and also parallel to an imaginary center line of the curtain coater.

In addition, it is expedient if the edge guides each have a pointed lower edge, which in each case expand outward.

Advantageously, the auxiliary guides are placed on the upper edges of the edge guides and firmly mounted with these. As a result, they can be adjusted together in the transverse direction.

The auxiliary guide are seen from the outside, ie transverse direction of the machine, wedge-shaped.

The surfaces of the side edge guides are inclined in the same direction as the inclined guide plate.

Incidentally, the existing lateral dividing plates are each permanently mounted on the surface of the relevant auxiliary guides. The surfaces of the auxiliary guides are inclined in the same direction as the surfaces of the auxiliary guides.

In addition, it is expedient if the dividing plates and the surfaces of the auxiliary guides are inclined in opposite directions to the edge guides and the guide plate.

Below the dividing plates is arranged continuously in the transverse direction collecting trough. This gutter can catch the lateral parts of the application medium, which flow away from the partition plates opposite to the flow direction of a medium application medium part on the guide plate, wherein the set middle section produces the desired application width.

According to the invention it is also provided that for adjusting the application width of the application medium in the transverse direction of a consisting of a bolt and a nut member positioning device is provided.

In each case a bolt is on the lateral outer surface of the

Edge guide and rotatably mounted above the guide plate. The nut member is positively connected to the respective bolt and at the same time firmly attached to the side surface of the guide plate.

The paint width adjusting device according to the present invention may be used in cases where a curtain head is used and a single layer is applied, but may be applied to the uppermost curtain head when two or more curtain heads are used for plural layers.

The effect and operation of the present invention are as follows.

The application medium, which is first output from the curtain head down over the entire width is divided by a device for adjusting the application width. The division takes place in a middle part and two lateral parts. That is to say, the lateral application medium parts each strike a dividing or separating plate. This partition plate is oppositely inclined to the inclination of the guide plate. The lateral application medium part flows down on the separating plate and is collected by the color pan underneath. On the other hand, the middle part, which flows As it is down, it hits and travels near the top of the guide plate and travels along its slope, moving from the lower edge of the downward curtain guide to the surface of the web. In this case, for the middle part of the job, the surfaces of the inside of the edge guide, the surface of the inside of the auxiliary guide and the surface of the inside of the dividing or separating plate form a uniform vertical guide plane. As a result, the side surfaces of the central part are guided by these vertical guide surfaces, and can fall down onto the web, without causing the side edges of the application layer (coating layer) to be pulled in as a result of the application medium surface tension.

By virtue of the inventive construction, it is not necessary to discharge into both ends of the slot in the curtain applicator head through which the application medium is dispensed, i. inside the curtain head, insert bays or insert a movable lid at both ends of the slot. This allows the interior of the curtain head to be kept clean. At the same time, the accuracy can be maintained.

Further, it is also possible to automatically perform the positioning of the web and curtain by detecting the lurching of the web and the associated movement of the application width adjustment device.

It is conceivable that the edge guides on the guide plate be extended to the lower edge of the guide plate, or an edge guide may be provided which has a pair of vertical guide planes which narrows the central part of the paint in the area from the curtain guide to the web.

The invention will be explained in more detail with reference to an embodiment.

• Figur 1a : eine Abbildung der Vorrichtung zur Einstellung der Strichbreite in dem Fall, wenn die Strichbreite schmal ist, in einem Seitenquerschnitt des Endes (Schnittzeichnung entlang Pfeile A-A),
• Figur 1 b: eine Rückansicht (Schnittzeichnung entlang Pfeile B-B).
• Figur 2 (C) : eine Abbildung der Vorrichtung zur Einstellung der Anstrichbreite in dem Fall, wenn die Strichbreite schmal ist, in einem Seitenquerschnitt des mittleren Teils (Schnittzeichnung entlang Pfeile C-C),
• Figur 2 (D) : eine Draufsicht (Schnittzeichnung entlang Pfeile D-D).
• Figur 3 (A) : ist eine Darstellung der Vorrichtung zur Einstellung der Anstrichbreite in dem Fall, wenn die Anstrichbreite schmal breit, in einem Seitenquerschnitt des Endes (Schnittzeichnung entlang Pfeile A-A),
• Figur 3 (B) : eine Rückansicht (Schnittzeichnung entlang Pfeile B-B).
• Figur 4 (C) : eine Abbildung der Vorrichtung zur Einstellung der Anstrichbreite in dem Fall, wenn die Anstrichbreite breit ist, in einem Seitenquerschnitt des mittleren Teils (Schnittzeichnung entlang Pfeile C-C),
• Figur 4 (D) : eine Draufsicht (Schnittzeichnung entlang Pfeile D-D).

Show it:

• FIG. 1a : An illustration of the device for adjusting the stroke width in the case where the line width is narrow, in a side cross section of the end (cross-sectional view along arrows AA),
• FIG. 1 b: a rear view (sectional drawing along arrows BB).
• FIG. 2 (C) Fig. 1 : an illustration of the paint width adjusting device in the case where the stroke width is narrow, in a side cross section of the middle part (sectional drawing along arrows CC),
• FIG. 2 (D) : a plan view (sectional view along arrows DD).
• FIG. 3 (A) : Is an illustration of the device for adjusting the coat width in the case when the coating width of narrow width, in a side cross section of the end (cross-sectional view along arrows AA),
• FIG. 3 (B) : a rear view (sectional drawing along arrows BB).
• FIG. 4 (C) : An illustration of the device for adjusting the coat width in the case when the coating width is wide, in a side cross section of the middle part (sectional view taken along arrows CC),
• FIG. 4 (D) : a plan view (sectional view along arrows DD).

Incidentally, in the figures, the same parts are denoted by the same designations as in FIG Figure 5 in which the conventional technique is described.

In these figures, 1 is the curtain head, which outputs the application medium t directed downwards. 2 is the guide plate which receives the medium t discharged from this curtain head 1 in the area of the upper edge of the slope 2a of the guide plate 2 and makes it flow down along the slope 2a and from the downward lower edge of the curtain guide 2b Curtain c moved to the surface of the web w. The upper edge of the guide plate 2 has a bent portion 2c. 9 is a device for adjusting the paint width. This device is arranged symmetrically to the vertical surfaces including the center line c1 of the curtain coater parallel. It is adjustable in the transverse direction (in width).

The paint width adjusting device 9 has a pair of edge guides 3 abutting against the side surfaces of the guide plate 2. The edge guides 3 extend downwardly from the upper edge of the guide plate 2 and are parallel to the surfaces on the inside and also to the center line c1 of the coater. The lower edge of the edge guide 3 is seen from the front (see FIG. 2 and 4 (D) pointed trained widens outwards. In addition, a pair of auxiliary guides 4 are provided, which are fixedly mounted in the region of the upper edges of the edge guides 3. The auxiliary guides are seen from the outside wedge-shaped (see FIG. 1a . 2C) . 3 (A) . 4 (C) ). The tops of the auxiliary guides 4 and the partition plates 5 arranged thereon are each inclined in opposite directions to the inclination of the guide plate 2 and the edge guides 3 resting thereon. Each dividing plate 5 is fixedly mounted on the surface of the associated auxiliary guide 4. The dividing or separating plate 5 is as in the figures FIG. 1a . 2 (C) . 3 (A) . 4 (C) shown bent downwards at the edge.

The surfaces of the inner sides of the edge guides 3 on the
Guide plate, the surfaces of the inner sides of the auxiliary guides 4 and the surfaces of the inner sides of the partition plate 5 form, as in FIG. 2 (D) and 4 (D) represented, a uniform vertical guide surface 9a.

Denoted by 6 is a device for positioning, with which the adjustment of the position of the device 9 for setting the stroke width in the transverse direction is made. The positioning device 6 consists of the bolts 6a and nuts 6b. The bolts 6 a are rotatably mounted on the side surfaces of the outer sides of the edge guides 3 on the guide plate 2. The nut members 6b, which are positively connected to the respective bolts 6a, are simultaneously fixedly mounted on the end surfaces of the guide plate 2.

Next, the operation of the embodiment of the present embodiment will be explained.

The discharged application medium t, which is output from the curtain head 1 downwards over the entire width, is subdivided by means of the arranged underneath device 9 for adjusting the application width in a central part tc and two lateral parts te. As a result, the part te strikes the partition plate 5 for both sides of the discharged medium t, which has a gradient opposite to the guide plate 2. The medium t flows down on the partition plate 5 and is collected by the ink tray 7. The middle part tc of the medium t, in contrast to the two edge parts te and tc, is directed downwards, hits in the region of the upper edge of the guide plate 2, flows downwards along its slope 2a and moves away from the latter bottom curtain curtain 2b as a curtain c on the surface of the web w, where the coating layer s is formed. In this case, for the middle part tc, the surface of the inside of the edge guide 3, the surface of the inside of the auxiliary guide 4 and the surfaces of the inside of the Separation plate 5 a uniform vertical guide surface 9a, so that the side surfaces of the central part tc is guided by this vertical guide surface 9a and so also on the slope 2a of the guide plate 2 passes without causing the unwanted retraction of the side edges of the application medium, and on the Guide plate 2 flows down.

The present invention is not limited to the configuration in the embodiment described above, but it may be changed as long as the main contents of the invention are not violated. For example, in the embodiment of the embodiment described above, a curtain head was used for single-layer application. However, the invention is also suitable for cases in which a multi-layer application is provided. There, the invention can be used for the top curtain head 1, where two or more curtain heads are present. Further, the positioning device 6 may not only consist of bolt 6a and nut member 6b as described, but it may also be a combination with a rack or a linear motor.

LIST OF REFERENCE NUMBERS

1

curtain head

1 a

Curtain head for the heat-sensitive layer

1 b

Curtain head for the protective layer

2

guide plate

2a

slope

2 B

curtain guide

2c

bent part

3

Edge guide on the plate

4

auxiliary guide

5

Dividing or separating plate

6

positioning device

6a

bolt

6b

nut element

7

paint tray

9

Device for adjusting the paint width

9a

vertical guide surface

c

curtain

c1

center line

S

application layer

Sat.

Lower class

sb

upper layer

t, ta, tb

application medium

tc

middle part

th

lateral part

w

Fibrous web

Claims (9)

Curtain coater for applying a liquid to pasty medium (t) on a running paper, - cardboard or other fibrous web (w), comprising a spaced from the fibrous web curtain head (1), of which the application medium (t, ta, tb) down directed, and comprising an inclined guide plate (2) which receives from the curtain head (1) application medium (t, ta, tb) in the region of the upper edge of the slope (2a) of the guide plate (2) and along the slope (2a) and wherein the application medium (t, ta, tb) falls from a curtain guide (2b) onto the surface of the web (w) in the form of a monolayer or multilayer curtain (c, ca, cb),
characterized in that
a device for adjusting the application width (9) is provided, which consists of a pair of adjustable edge guides (3), a pair of auxiliary guides (4) and a pair of partition plates (5), wherein in each case the surface of the inside of the edge guide ( 3), the surface of the inside of the auxiliary guide (4) and the surface of the inside of the partition plate (5) forms a uniform vertical guide surface (9a) for the curtain (c). Curtain coater according to claim 1,
characterized in that
the edge guides (3) abut each other on the side of the guide plate (2) and extend downwardly from the upper portion of the guide plate (2), the inner sides of the edge guides (3) parallel to each other and also to an imaginary center line (c1) of the curtain coater are. Curtain coater according to claim 1 or 2,
characterized in that
the edge guides (3) each have a pointed lower edge. Curtain coater according to at least one of claims 1 to 3,
characterized in that
the auxiliary guides (4) are placed on the upper edges of the edge guides (3) and fixedly mounted with these. Curtain coater according to at least one of claims 1 to 4,
characterized in that
the surfaces of the lateral edge guides (3) are inclined in the same direction as the guide plate (2). Curtain coater according to at least one of the preceding claims,
characterized in that
the lateral partition plates (5) are respectively fixedly mounted on the surface of the respective auxiliary guides (4), the surfaces of the auxiliary guides (4) being inclined in the same direction as the surfaces of the auxiliary guides (4). Curtain coater according to at least one of the preceding claims,
characterized in that
the partition plates (5) and the surfaces of the auxiliary guides (4) are inclined in opposite directions to the edge guides (3) and the guide plate (2). Curtain coater according to at least one of the preceding claims,
characterized in that
below the dividing plates (5) a collecting trough (7) is arranged,
which collects the lateral parts of the application medium (te), which flow away from the partition plates (5) opposite to the flow direction of a middle application medium part (tc) on the guide plate (2). Curtain coater according to at least one of the preceding claims,
characterized in that
a positioning device (6) consisting of a screw bolt (6a) and a nut element (6b) is provided for adjusting the application width of the application medium, the bolt (6a) being respectively provided on the lateral outer surface of the edge guide (3) and above the guide plate (2) is rotatably mounted, and wherein the nut member (6b) with the respective bolt (6a) is positively connected, and at the same time firmly attached to the side surface of the guide plate (2).

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