Patent Description:
In general, a Flexible Printed Circuit Board (FPCB) includes a flexible insulating substrate and a metal circuit pattern formed by patterning a metal film, such as Cu foil, on one or both surfaces of the insulating substrate. Since the FPCB may be bent and formed with three-dimensional wiring, space may be efficiently utilized, thereby reducing the size and weight. Accordingly, the FPCB is widely used in various products using thin electronic components.

In addition, the FPCB further includes a coverlay made of a material, such as polyimide film, bonded to the insulating substrate by using a laminator to cover the metal circuit pattern in order to protect the metal circuit pattern printed on the insulating substrate.

As described above, the laminator for bonding the coverlay to the insulating substrate on which the metal circuit pattern is formed may be largely divided into a method using a heating roll and a method using a hot press.

The method using the heating roll has the advantage in that the time required for the bonding process is relatively shorter than the method using the hot press. The method using the hot press cuts the substrate and the coverlay film to a certain size, aligns the cut substrate and coverlay film, and then heat-compresses the substrate and the coverlay film, so that there is a problem in that the time required for the bonding process is relatively long, and the overall apparatus for implementing the bonding process is also complicated. On the other hand, in the method using the heating roll, the time required for the bonding process may be relatively reduced because the heating roll bonds the substrate and the coverlay while continuously moving the substrate and the coverlay film.

However, the method using the heating roll may be easily applied to the manufacturing of a Flexible Flat Cable (FFC) that does not require precise alignment between the substrate and the film, but is not easily applied to the manufacturing of flexible printed circuit boards that require precise alignment when the substrate and the film are bonded. This is because, since the coverlay has to selectively cover the metal circuit pattern printed on the substrate, precise alignment of the substrate and the coverlay film which continuously move toward the heating roll is required. However, there is a problem in that it is difficult to precisely maintain the alignment state of the two types of substrates which are to be bonded to each other in the Roll-to-Roll (R2R) processing.

<CIT> provides an apparatus for manufacturing a flexible flat cable including a core film supply unit in both sides of a wire. <CIT> provides a method for producing a hybrid multi junction photovoltaic device. <CIT> provides a laminating device of a flexible printed circuit board and a method thereof to adjust a pre-heated section according to a thickness and a material of a copper film and upper and lower dry films by adjusting incident angles of the copper film and the upper and the lower dry films. <CIT> provides a coverlay attaching apparatus for an FPCB(Flexible Printed Circuit Board) automatically performing a coverlay film attaching process. <CIT> provides an exposure apparatus capable of minimizing an error generated in an exposure process. <CIT> provides a manufacturing method of a film carrier tape which is produced with high productivity and readily under quality controls.

Therefore, an object of the present invention to solve this problem is to provide a laminator which performs a bonding process with a Roll-to-Roll (R2R) processing method to improve productivity, and improve precision by controlling tension.

The present invention provides a laminator, as defined by independent claim, including: a substrate supply part for supplying a substrate on which a metal pattern is formed for each predetermined unit area; a coverlay supply part for supplying a film to which a plurality of coverlays punched to a predetermined size is attached; a heating roller part for bonding the substrate and the film so that the plurality of coverlays respectively covers the metal pattern; a substrate tension adjustment part for adjusting tension of the substrate transferred to the heating roller part; a film tension adjustment part for adjusting the tension of the film transferred to the heating roller part; a bonding state image photographing part for measuring an interval between the plurality of coverlays after the heating roller part bonds the substrate and the film; and an adjustment part for adjusting any one or more of the tension of the substrate adjusted by the substrate tension adjustment part and the tension of the film adjusted by the film tension adjustment part so that the interval between the plurality of coverlays measured by the bonding state image photographing part maintains a preset allowable interval.

Each of the substrate tension adjustment part and the film tension adjustment part may include: a pair of tension adjusting fixed rollers; a pair of tension adjusting variable rollers; and a tension adjusting cylinder for adjusting a distance between the pair of tension adjusting fixed rollers and the pair of tension adjusting variable rollers by moving positions of the pair of tension adjusting variable rollers. The tension adjusting cylinder may operate pneumatically or hydraulically.

The adjustment part may adjust the pneumatic or hydraulic pressure supplied to the tension adjusting cylinder.

Further, the metal pattern may be formed on each of both surfaces of the substrate. Further, the coverlay supply part may include: a first coverlay supply part for supplying a film which is to be bonded to one surface of the substrate; and a second coverlay supply part for supplying a film which is to be bonded to the other surface of the substrate.

The film tension adjustment part may include: a first film tension adjustment part for adjusting the tension of the film supplied by the first coverlay supply part; and a second film tension adjustment part for adjusting the tension of the film supplied by the second coverlay supply part.

The substrate supply part may include: a substrate winder on which the substrate is wound; and a substrate feeder for transferring the substrate wound on the substrate winder to the heating roller part. Further, the coverlay supply part may include: a film winder on which the film is wound; and a film feeder for transferring the film wound on the film winder to the heating roller part.

The heating roller part may include: a pair of first heating rollers opposite to both surfaces of the substrate; and a pair of second heating rollers opposite to both surfaces of the substrate, located behind the pair of first heating rollers to secondarily heat the substrate and the film primarily heated by the pair of first heating rollers.

Further, the bonding state image photographing part may include: a first bonding state image photographing part for measuring an interval between the plurality of coverlays in the substrate and the film bonded by the pair of first heating rollers; and a second bonding state image photographing part for measuring an interval between the plurality of coverlays in the substrate and the film bonded by the pair of second heating rollers.

According to the present invention, the heating roller part includes: a pair of heating rollers opposite to both surfaces of the substrate; and a position variable support device for adjusting an interval between the pair of heating rollers by moving a position of any one of the pair of heating rollers.

The position variable support device includes: a ball screw shaft; a support body screwed to the ball screw shaft and supporting any one of the pair of heating rollers; and a servo motor for rotating the ball screw shaft to move a position of the support body.

Further, the position variable support device may further include a load cell for measuring a load applied to the support body. Further, the servo motor may move the position of the support body so that the load measured by the load cell is maintained within a preset load range.

Further, according to the present invention, the position variable support device further includes an air balancer for maintaining a horizontal state of the support body.

The laminator may further include: a substrate edge position controller provided between the substrate tension adjustment part and the heating roller part to adjust an edge position of the substrate transferred to the heating roller part; and a film edge position controller provided between the film tension adjustment part and the heating roller part to adjust an edge position of the film transferred to the heating roller part.

Further, the laminator may further include an edge image photographing part for photographing each of an edge of the substrate passing through the substrate edge position controller and an edge of the film passing through the film edge position controller.

Further, when the edge position of the substrate or the edge position of the film photographed by the edge image photographing part is out of a preset allowable position, the substrate edge position controller or the film edge position controller may adjust the edge position of the substrate or the edge position of the film.

The laminator may further include a film removing part for removing the film from the substrate in a state in which the plurality of coverlays is bonded to the substrate after the heating roller part bonds the substrate and the film such that the plurality of coverlays covers the metal pattern formed on the substrate.

Further, the laminator may further include a film removal image photographing part for checking whether the metal pattern formed on the substrate and the coverlay covering the metal pattern are defective after the film removing part removes the film bonded to the substrate.

According to the exemplary embodiment of the present invention, the laminator performs bonding with a Roll-to-Roll (R2R) processing method to improve productivity, and improve precision by controlling tension.

Hereinafter, an exemplary embodiment of the present invention will be described in detail with reference to accompanying drawings so as for those skilled in the art to easily carry out the present invention. The present invention can be implemented in various forms and is not limited to the exemplary embodiment described herein.

It should be noted that the drawings are schematic and not drawn to scale. Relative dimensions and proportions of parts in the drawings are shown exaggerated or reduced in size for clarity and convenience in the drawing, and a predetermined dimension is simply illustrative only and not limiting. Further, the same reference numerals are used for the same structure, element, or component shown in the two or more drawings in order to denote like features.

An exemplary embodiment of the present invention specifically represents an ideal embodiment of the present invention. As a result, various modifications of the drawings are expected. Accordingly, the exemplary embodiment is not limited to a specific form of the illustrated area, and includes, for example, a shape modification by manufacturing.

Hereinafter, a laminator <NUM> according to an exemplary embodiment of the present invention will be described with reference to <FIG>. The laminator <NUM> according to the exemplary embodiment of the present invention may be used for manufacturing a Flexible Printed Circuit Board (FPCB). In this case, the FPCB may include a substrate <NUM> made of a flexible insulating material, a metal pattern <NUM> formed by patterning a metal film on one or both surfaces of the substrate <NUM>, and a coverlay <NUM> bonded to the substrate <NUM> to cover the metal pattern <NUM>. For example, the substrate <NUM> and the coverlay <NUM> may be made of polyimide, and the metal film may be made of Cu foil. That is, the metal pattern <NUM> may be formed of copper (Cu).

As illustrated in <FIG> and <FIG>, the laminator <NUM> according to the exemplary embodiment of the present invention includes a substrate supply part <NUM>, coverlay supply parts <NUM> and <NUM>, a heating roller part <NUM>, and a substrate tension adjustment part <NUM>, film tension adjustment parts <NUM> and <NUM>, a bonding state image photographing part <NUM>, and an adjustment part <NUM>.

In addition, the laminator <NUM> according to the exemplary embodiment of the present invention may further include a substrate edge position controller <NUM>, film edge position controllers <NUM> and <NUM>, an edge image photographing part <NUM>, a film removing part <NUM>, and a film removal image photographing part <NUM>.

The substrate supply part <NUM> supplies the substrate <NUM> on which the metal pattern <NUM> is formed for each predetermined unit area. Specifically, the substrate supply part <NUM> may include a substrate winder <NUM> on which the substrate <NUM> on which the metal pattern <NUM> is formed is wound, and a substrate feeder <NUM> for transferring the substrate <NUM> wounded on the substrate winder <NUM> to the heating roller part <NUM> which is to be described below.

In addition, the metal pattern <NUM> may be formed on one surface of the substrate <NUM> or may be formed on both surfaces of the substrate <NUM>. Hereinafter, in the present specification, as illustrated in <FIG>, a case in which the metal patterns <NUM> are formed on both surfaces of the substrate <NUM> will be described as an example.

The coverlay supply parts <NUM> and <NUM> supply a film <NUM> to which a plurality of coverlays <NUM> punched to a predetermined size are attached. Specifically, the coverlay supply parts <NUM> and <NUM> may include film winders <NUM> and <NUM> on which the film <NUM> to which the plurality of coverlays <NUM> are attached is wound, and film winders <NUM> and <NUM> for transferring the film wound on the film feeders <NUM> and <NUM> to the heating roller part <NUM> which is to be described below.

In addition, the coverlay supply parts <NUM> and <NUM> may include a first coverlay supply part <NUM> supplying the film which is to be bonded to one surface of the substrate <NUM>, and a second coverlay supply part <NUM> supplying the film which is to be bonded to the other surface of the substrate <NUM>.

The heating roller part <NUM> bonds the substrate <NUM> and the film <NUM> so that each of the plurality of coverlays <NUM> attached to the film <NUM> covers the metal pattern <NUM> formed on the substrate <NUM>.

Specifically, the heating roller part <NUM> may include a pair of heating rollers <NUM> and <NUM> and a pair of heating rollers <NUM> and <NUM> opposite to both surfaces of the substrate <NUM>, and a position variable support device <NUM> for adjusting an interval between the pair of heating rollers <NUM> and <NUM> and the pair of heating rollers <NUM> and <NUM> by moving a position of any one of the pair of heating rollers <NUM> and <NUM> and the pair of heating rollers <NUM> and <NUM>.

An induction coil is installed inside the pairs of heating rollers <NUM>, <NUM>, <NUM>, and <NUM>, and the eddy current induced by a magnetic force line generated when an alternating current flows through the induction coil flows through the surface of the roller and the roller itself generates heat. In addition, a heat pipe having high-performance heat transfer characteristics is installed on the surface of the roller, so that the temperature deviation of the roller surface may be maintained within <NUM> degrees. The heating rollers <NUM>, <NUM>, <NUM>, and <NUM> manufactured as described above have excellent thermal efficiency, semi-permanent lifespan, and uniform temperature distribution, so that the substrate <NUM> and the film <NUM> may be uniformly bonded.

As illustrated in <FIG>, the variable position support device <NUM> includes a ball screw shaft <NUM>, a support body <NUM> screwed to the ball screw shaft <NUM> and supporting any one of the pairs of heating rollers <NUM>, <NUM>, <NUM>, <NUM>, and a servo motor <NUM> for rotating the ball screw shaft <NUM> to move a position of the support body <NUM>.

In addition, the variable position support device <NUM> may further include a load cell <NUM> for measuring a load applied to the support body <NUM> supporting the heating rollers <NUM>, <NUM>, <NUM>, and <NUM>. Further, the servo motor <NUM> may move the position of the support body <NUM> so that the load measured by the load cell <NUM> is maintained within a preset load range.

In addition, the position variable support device <NUM> may further include an air balancer <NUM> for maintaining a horizontal state of the support body <NUM>.

As such, in the exemplary embodiment of the present invention, it is possible to evenly maintain force of compressing the substrate <NUM> and the film <NUM> by the pairs of heating rollers <NUM>, <NUM>, <NUM>, <NUM> through the load cell <NUM> and the air balancer <NUM>.

Further, the heating roller part <NUM> may include a pair of first heating rollers <NUM> opposite to both surfaces of the substrate <NUM>, and a pair of second heating rollers <NUM> opposite to both surfaces of the substrate <NUM>, located behind the pair of first heating rollers <NUM>, and finally heating the substrate <NUM> and the film <NUM> which have been primarily heated by the pair of first heating rollers <NUM>.

In order to bond the substrate <NUM> and the film <NUM>, the heating rollers <NUM>, <NUM>, <NUM>, and <NUM> need to maintain a fairly high temperature, and when the substrate <NUM> and the film <NUM> pass through the high-temperature heating rollers <NUM>, <NUM>, <NUM>, and <NUM> at once, the heat is not sufficiently transferred to the inside of the substrate <NUM> and the film <NUM>, resulting in poor bonding.

Therefore, the heating roller part <NUM> uses the pair of first heating rollers <NUM> and the pair of second heating rollers <NUM>, and heat is gradually transferred into the substrate <NUM> and the film <NUM> by primarily heating the substrate <NUM> and the film <NUM> to a temperature relatively lower than the temperature required for bonding with the first heating roller <NUM>, and then finally heating the substrate <NUM> and the film <NUM> to the temperature required for bonding with the second heating roller <NUM>, thereby firmly bonding the substrate <NUM> and the film <NUM>.

The substrate tension adjustment part <NUM> adjusts the tension of the substrate <NUM> supplied by the substrate supply part <NUM> to the heating roller part <NUM>, and the film tension adjustment parts <NUM> and <NUM> adjust the tension of the film <NUM> supplied by the coverlay supply parts <NUM> and <NUM> to the heating roller part <NUM>. Further, the film tension adjustment parts <NUM> and <NUM> may include a first film tension adjustment part <NUM> for adjusting the tension of the film <NUM> supplied by the first coverlay supply part <NUM>, and a second film tension adjustment part <NUM> for adjusting the tension of the film <NUM> supplied by the second coverlay supply part <NUM>.

In addition, the substrate tension adjustment part <NUM>, the first film tension adjustment part <NUM>, and the second film tension adjustment part <NUM> have the same basic structure except for a different subject for adjusting the tension. Hereinafter, in the present specification, a detailed configuration will be described with reference to <FIG> based on the first film tension adjustment part <NUM> as a representative example. That is, the detailed configurations of the substrate tension adjustment part <NUM> and the second film tension adjustment part <NUM> are the same as that of the first film tension adjustment part <NUM>.

The first film tension adjustment part <NUM> includes a pair of tension adjusting fixed rollers <NUM>, a pair of tension adjusting variable rollers <NUM>, and a tension adjusting cylinder <NUM> for adjusting the distance between the pair of tension adjusting fixed rollers <NUM> and the pair of tension adjusting variable rollers <NUM> by moving the position of the pair of tension adjusting variable rollers <NUM>. Here, the tension adjusting cylinder <NUM> operates pneumatically or hydraulically.

When the distance between the pair of tension adjusting fixed rollers <NUM> and the pair of tension adjusting variable rollers <NUM> is adjusted while the tension adjusting cylinder <NUM> is expanded and contracted, the tension applied to the film <NUM> passing through the pair of tension adjusting fixed rollers <NUM> and the pair of tension adjusting variable rollers <NUM> is adjusted. For example, when the distance between the pair of tension adjusting fixed rollers <NUM> and the pair of tension adjusting variable rollers <NUM> increases, the tension applied to the film <NUM> increases, and when the distance between the pair of tension adjusting fixed rollers <NUM> and the pair of tension adjusting variable rollers <NUM> decreases, the tension applied to the film <NUM> decreases.

The bonding state image photographing part <NUM> measures the interval between the plurality of coverlays <NUM> after the heating roller part <NUM> bonds the substrate <NUM> and the film <NUM> to each other. <FIG> illustrates the coverlay <NUM> bonded to the substrate <NUM>. In this case, the two bonding state image photographing parts <NUM> and <NUM> may photograph the coverlay <NUM> bonded to one surface of the substrate <NUM> and the coverlay <NUM> bonded to the other surface of the substrate <NUM>, respectively.

Further, the bonding state image photographing unit <NUM> may include a first bonding state image photographing part <NUM> for measuring the interval between the plurality of coverlays <NUM> in the substrate <NUM> and the film <NUM> bonded by the pair of first heating rollers <NUM>, and a second bonding state image photographing part <NUM> for measuring the interval between the plurality of coverlays <NUM> in the substrate <NUM> and the film <NUM> bonded by the pair of second heating rollers <NUM>.

For example, as described above, a total of four bonding state image photographing parts <NUM> (<NUM>, <NUM>, <NUM>, and <NUM>) may be installed. However, one exemplary embodiment of the present invention is not limited thereto, and the number of bonding state image photographing parts <NUM> may be adjusted depending on whether the metal pattern <NUM> is formed on both surfaces of the substrate <NUM> or on one surface of the substrate <NUM> and the number of heating rollers <NUM>, <NUM>, <NUM>, and <NUM> used in the heating roller part <NUM>.

The adjustment part <NUM> adjusts one or more of the tension of the substrate <NUM> adjusted by the substrate tension adjustment part <NUM> and the tension of the film <NUM> adjusted by the film tension adjustment parts <NUM> and <NUM> so that the interval between the plurality of coverlays <NUM> measured by the bonding state image photographing part <NUM> maintains a preset allowable interval. In this case, the adjustment part <NUM> adjusts the pneumatic or hydraulic pressure supplied to the substrate tension adjustment part <NUM> or the tension adjustment cylinder <NUM> of the film tension adjustment parts <NUM> and <NUM> to adjust the tension applied to the substrate <NUM> or the film <NUM>. For example, the adjustment part <NUM> may be a regulator for adjusting the pneumatic pressure supplied to the tension adjusting cylinder <NUM>.

Specifically, when the interval between the plurality of coverlays <NUM> measured by the bonding state image photographing part <NUM> is smaller than the preset allowable interval, the adjustment part <NUM> increases the tension applied to the film <NUM> to increase the interval between the plurality of coverlays <NUM>. Conversely, when the interval between the plurality of coverlays <NUM> measured by the bonding state image photographing part <NUM> is larger than the preset allowable interval, the adjustment part <NUM> decreases the tension applied to the film <NUM> to decrease the interval between the plurality of coverlays <NUM>.

In addition, when the intervals between the plurality of coverlays <NUM> measured by the bonding state image photographing part <NUM> are measured differently due to a difference occurring at both ends in the width direction, it may be determined that abnormality has occurred in the equipment.

The substrate edge position controller (EPC) <NUM> is provided between the substrate tension adjustment part <NUM> and the heating roller part <NUM> to adjust an edge position of the substrate <NUM> transferred to the heating roller part <NUM>.

The film edge position controllers <NUM> and <NUM> are provided between the film tension adjustment parts <NUM> and <NUM> and the heating roller part <NUM> to adjust the edge position of the film <NUM> transferred to the heating roller part <NUM>. Further, the film edge position controllers <NUM> and 430may include a first film edge position controller <NUM> provided between the first film tension adjustment part <NUM> and the heating roller part <NUM>, and a second film edge position controller <NUM> provided between the second film tension adjustment part <NUM> and the heating roller part <NUM>.

The edge image photographing part <NUM> photographs the edge position of the substrate <NUM> passing through the substrate edge position controller <NUM> and the edge position of the film <NUM> passing through the film edge position controllers <NUM> and <NUM>. In addition, the edge image photographing part <NUM> may also be divided into a substrate edge image photographing part <NUM>, a first film edge image photographing part <NUM>, and a second film edge image photographing part <NUM> depending on the object to be photographed.

<FIG> is an enlarged perspective view illustrating the substrate edge position controller <NUM> and the substrate edge image photographing part <NUM>. Also, the film edge position controllers <NUM> and <NUM> and the film edge image photographing parts <NUM> and <NUM> may be provided in the same manner as in <FIG>. The substrate edge position controller <NUM> accurately aligns and winds the edge position of the substrate which is to be wound in a form developed from the general winder, thereby increasing the accuracy of the subsequent process.

When the edge position of the substrate <NUM> or the edge position of the film <NUM> photographed by the edge image photographing part <NUM> is out of a preset allowable position, the substrate edge position controller <NUM> or the film edge position controllers <NUM> and <NUM> adjust the edge position of the substrate <NUM> or the edge position of the film <NUM>.

After the heating roller part <NUM> bonds the substrate <NUM> and the film <NUM> so that the plurality of coverlays <NUM> covers the metal pattern <NUM> formed on the substrate <NUM>, the film removing part <NUM> removes the film <NUM> from the substrate <NUM> in the state where each of the plurality of coverlays <NUM> is bonded to the substrate <NUM>.

After the film removing part <NUM> removes the film <NUM> bonded to the substrate <NUM>, the film removal image photographing part <NUM> may finally check defects of the metal pattern <NUM> formed on the substrate <NUM> and the coverlay <NUM> covering the metal pattern.

By the foregoing configuration, the laminator <NUM> according to the exemplary embodiment of the present invention performs bonding by a roll-to-roll (R2R) processing method to improve productivity, and improve precision by controlling tension.

In addition, since the heating roller part <NUM> includes the pair of first heating rollers <NUM> and the pair of second heating rollers <NUM>, it is possible to effectively bond the substrate <NUM> and the film <NUM> and suppress the occurrence of bonding defects.

In addition, the position variable support device <NUM> supporting the heating roller part <NUM> may adjust the interval between the pair of heating rollers <NUM> and <NUM> to evenly compress the substrate <NUM> and the film <NUM>.

In addition, in addition to the bonding state image photographing part <NUM>, the edge image photographing part <NUM> and the film removal image photographing part <NUM> may detect the occurrence of defects in the bonding process.

The exemplary embodiments of the present invention have been described with reference to the accompanying drawings, but those skilled in the art will understand that the present disclosure may be implemented in another specific form within the scope of the invention as defined by the appended claims.

The laminator according to the exemplary embodiment of the present invention may be used for improving productivity by performing a bonding process with a Roll-to-Roll (R2R) processing method and improving precision by controlling tension.

Claim 1:
A laminator (<NUM>), comprising:
a substrate supply part (<NUM>) for supplying a substrate (<NUM>) on which a metal pattern (<NUM>) is formed for each predetermined unit area;
a coverlay supply part (<NUM>, <NUM>) for supplying a film (<NUM>) to which a plurality of coverlays (<NUM>) punched to a predetermined size is attached;
a heating roller part (<NUM>) for bonding the substrate (<NUM>) and the film (<NUM>) so that the plurality of coverlays (<NUM>) respectively covers the metal pattern (<NUM>);
a substrate tension adjustment part (<NUM>) for adjusting tension of the substrate (<NUM>) transferred to the heating roller part (<NUM>);
a film tension adjustment part (<NUM>, <NUM>) for adjusting the tension of the film (<NUM>) transferred to the heating roller part (<NUM>);
a bonding state image photographing part (<NUM>) for measuring an interval between the plurality of coverlays (<NUM>) after the heating roller part (<NUM>) bonds the substrate (<NUM>) and the film (<NUM>); and
an adjustment part (<NUM>) for adjusting any one or more of the tension of the substrate (<NUM>) adjusted by the substrate tension adjustment part (<NUM>) and the tension of the film (<NUM>) adjusted by the film tension adjustment part (<NUM>, <NUM>) so that the interval between the plurality of coverlays (<NUM>) measured by the bonding state image photographing part (<NUM>) maintains a preset allowable interval,
wherein the heating roller part (<NUM>) includes:
a pair of heating rollers (<NUM>, <NUM>) opposite to both surfaces of the substrate (<NUM>); and
a position variable support device (<NUM>) for adjusting an interval between the pair of heating rollers (<NUM>, <NUM>) by moving a position of any one of the pair of heating rollers (<NUM>, <NUM>),
characterized in that the position variable support device (<NUM>) includes:
a ball screw shaft (<NUM>);
a support body (<NUM>) screwed to the ball screw shaft (<NUM>) and supporting any one of the pair of heating rollers (<NUM>, <NUM>);
a servo motor (<NUM>) for rotating the ball screw shaft (<NUM>) to move a position of the support body (<NUM>); and
an air balancer (<NUM>) for maintaining a horizontal state of the support body (<NUM>).