GB2135934A - Laminated paper sheet - Google Patents

Abstract

Paper sheets (54) whose ends overlap are laminated in succession to a continuous plastics film (32), and then a gap is cut by cutter (76) in the laminated film, before the film is tensed in order to break the film at the cut gap. The film may be of polypropylene or PVC and is coated with a solvent based adhesive by rollers (34,36). The solvent is evaporated in an oven (52) before the film is pressed against the sheets by rollers (60,62,64). The laminate is stretched between sets of rollers (72,74) after the cutting action by virtue of their differing rotational speeds. Thereby, laminating operation of sheet paper can extremely be automated and the laminated sheet paper without any flaw can be assured. <IMAGE>

Description

SPECIFICATION Method and apparatus for laminating sheet paper The present invention relates generally to a technique for laminating synthetic resin film on printed sheet papers, or more precisely, to method and apparatus for laminating sheet paper wherein sheet papers whose margins are piled up one above another are laminated in succession, and then a gap is cut in the laminated film, and finally the film is tensed in orderto breakthefilm from the gap.

B. Description ofpriorArts.

For beautifying printed book cover or wrapper, transparent or semi-transparent synthetic resin film is laminated on these cover or so forth. That is because a mere printed paper lacks luxuriance and a surface of such paper can not be protected. Accordingly, the surface of printed paper is laminated with a film such as polypropylene or polyvinyl chloride film. Lamination of such film onto the surface of paper is comperatively easy, as the film coated with adhesive is pasted on the paper. Especially, in case the paper is a roll paper, in other words, a continuous belt-like paper, the film which is also a belt-like is merely united with the roll paper and the laminated roll paper is continuously taken up by a roller.

But, things have been quite different in case the paper is a sheet paper, in other words, a paper of determined size. That is because, if sheet paper is laminated by roll film, the laminated roll film should be cut in accordance with the size of sheet paper and every divided sheet paper should be obtained.

In the prior art, belt-like synthetic resin film is laminated on the surface of sheet papers which are arranged in succession and a gap is cut by a knife at the boundary line of each sheet papers. The laminated sheet papers are then pulled and tensed by two workers for separating every laminated sheet papers.

But, such manual operation is not efficient and tends to generate undesirable flaw on the film surface. Moreover, spacious area is needed for such manual operation, therefore, the cost for production becomes expensive.

Summary of the Invention Accordingly, it is a main object of the present invention to provide method and apparatus by which lamination of sheet paper can completely be automated.

Other object of the present invention is to provide method and apparatus for efficiently laminating sheet paper.

Further object of the present invention is to provide improved method and apparatus for laminating sheet paper by which fine quality can be expected.

To achieve these objects, according to the present invention, sheet papers whose margins are piled up one above another are laminated in succession, and then a gap is cut in the laminated film, and finally the film is tensed in orderto break the film from the gap.

These and further objects of the present invention will be more clearly understood by the following descriptions with reference to the attached drawings. But, these are only examples of the invention and the present invention shall not be limited to those examples.

Figure 1 is a diagram showing an outline of laminating method according to the present invention.

Figure 2 is a side elevation illustrating an embodiment of laminating apparatus according to the present invention.

Figure 3 is a partial plan view showing laminating apparatus of Figure 2.

Figure 4 is a cross-sectional view illustrating the laminated sheet papers whose margins are piles up one above another.

Figure 5 is a plan view in which a gap is cut to the laminated film by a rotary cutter.

Detailed Description of Preferred Embodiments At first, processes of method for laminating sheet paper according to the present invention will be roughly described hereinunder with reference to Figure 1. A film to be laminated is prepared in the form of roll film in a process indicated by numeral 10. The material of film will be detailed later. In a process indicated by numeral 12, an adhesive is pasted on a surface of film and, in a next process indicated by numeral 14, volatile solvent in the adhesive is dried up. Then, the film is forwarded to a laminating process indicated by numeral 16.

On the other hand, numbers of sheet papers to be laminated are stocked in a pile and every papers are sucked up by air sucking means in a process indicated by numeral 18. Then, every sheets are forwarded one by one on a conveyer in a process indicated by numeral 20 and, during its progress, positioning in relation to its progressing direction and transverse direction is carried out. It is to be noted, in a process indicated by numeral 22, margins of continuously progressing sheet papers are piled up one above another. (See Figure 4) The film and sheet paper which are separately supplied are continuously laminated in a process indicated by numeral 16. (See also Figure 4) Then, in a process identified by numeral 24, a gap is cut in the laminated film on sheet papers. Detail of the gap will be described later, as the gap is closedly related to material of laminated film.As shown in Figure 5, the gap is cut in the portion of laminated film corresponding the piled up portion of sheet paper's margin.

Next, the laminated sheet papers whose film is gapped are holded between pairs of rollers in a process identified by numeral 26, and, in addition, the papers are tensed (stretched) in the same direction of their progress. Tensile force is generated by setting the rotation speed of front pair rollers faster than that of rear pair rollers. Upon tensile force, the gapped laminate film is broken from the gap at right angles with the progressing direction, thereby, every laminated sheet papers are separately obtained. Finally, numbers of laminated sheet papers are piled and stocked in a process indicated by numeral 28.

Next, apparatus for laminating sheet paper according to the present invention will be detailed hereinunder with reference to Figures 2 to 5.

Synthetic resin film which is to be used for lamination is prepared in a form of roll film 32 around a roller axis 30. With regard to the nature of roll film 32, most of such roll film 32 is of polypropylene or polyvinyl chloride. Polypropylene film has almost no elongation and, upon strectching, the film is easily broken. On the other hand, polyvinyl chloride film can easily be elongated upon stretching and the film is hardly broken. Taking fully into consideration of these natures of film 32, laminating apparatus shall be designed.

Roll film 32 is sequentially pulled out from the roller axis 30 and an adhesive is coated on its surface for lamination. The adhesive is a well-known resin adhesive in which volatile solvent is contained.

Numeral 34 indicates a coating roller, numeral 36 a press roller, numeral 38 a ductor roller for adjusting a thickness of coated adhesive. These coating roller 34 and press roller 36 are interlockingly rotated by a motor 40. The adhesive is supplied by a gear pump not shown to a fountain between the coating roller 34 and the ductor roller 38. Surplus adhesives are returned to a tank and only the well-mixed adhesives are stored in the fountain and the adhesives are transferred from the coating roller 34 to the roll film 32.

In order to get rid of the solvent, the roll film 32 on which the adhesive was coated is forwarded to drying process by way of a plurality of guide rollers.

Tunnel-type drying means is adopted in the embodimentwhich is suitable for drying the roll film 32 passing through it. Tunnel-type drying means comprise, a blower 42, a heater 44, a ventilation fan 46, an exhaust fan 48, a guide roller 50 and a tunnel 52.

Detail of these components is omitted because they are already well known. In this way, the film for lamination is prepared.

On the other hand, numbers of sheet papers 54to be laminated are piled up on a sheet table 56, setting the printed surface the front surface. Then, these sheet papers 54 are sucked up by well known air sucker one by one and forwarded to paper supplying means 58 which are composed of tape conveyer and means for positioning in relation to progressing direction and transverse direction. Margins of continuously progressing sheet papers are piled up one above another by the paper supply means 58 and the sheet papers 54 are forwarded in succession. Such piling up of margins of sheet papers 54 is achieved buy a combination of the speed of tape conveyer and the movement of positioning means. Sheet papers 54 successively forwarded with their margins piled up are then, as shown in Figure 4, continuously laminated by the roll film 32 on which the adhesive is coated.Numeral 60 indicates preparatory laminate rollers and between these rollers 60, the printed surface of sheet papers 54 are temporarily adhered with the roll film 32.

Sheet papers 54 and roll film 32 temporarily attached with each other are then fed between a laminate roller 62 and a press roller 64to laminate them formally. An infrared heater is housed within the laminate roller 62 so that a lamination temperature will be kept constant by an automatic temperature adjuster in the infrared heater, thereby, a product quality is maintained by a stable heating.

The press roller 64 is of oil pressure type and is pressed against the laminate roller 62. The pressure of the press roller 64 can be adjusted by adjusting gauge in accordance with the classification of roll film 32. The laminate roller 62 is driven by motor 66 and variable speed means 68, so as to vary the lamination speed.

In Figure 4, the roll film 32 is laminated on the sheet paper 54. A sheet of roll film 32 is adhered to the portion where margins of continued sheet paper 54 are piled up one above another.

The roll film 32 adhered to the sheet papers 54 comes in contact with a cooling roller 70. Then, the adhesive is solidified rapidly and the sheet papers 54 are calendered.

Laminated sheet papers 54 which have passed through the cooling roller 70 are then forwarded between pairs of rollers. Numeral 72 indicates a pair of leading rollers, numeral 74 a pair of separation rollers. Peripheral speed of separation rollers 74 is faster than that of a pair of leading rollers 72. (These rollers are driven by the motor 66 or other motor not shown.) A cutter 76 is provided for cutting a gap in the laminate film in the middle of these pairs of rollers 72,74. The laminate film 32 shall be broken at the piled up portion in order to separate the sheet papers 54 one by one which were continuously laminated by a sheet of roll film 54. The gap cut by the cutter 76 is a start point of the separation. Pairs of rollers are for breaking the roll film, starting from the gap by tensile strength.The nature of roll film 32 shall strictly be taken into consideration when cutting the roll film 32 by cutter 76. In case the roll film 32 is a polypropylene film which has almost no elongation and is easily broken upon stretching, the gap may cut in one side of the roll film 32. The polypropylene roll film is instantaneously broken from the gap upon receiving the tensile strength by pairs of rollers 72,74. Without saying, the gap is cut in the piled up portion of sheet papers 54, as shown in Figure 4. Accordingly, a side cutter may be used for cutter 76 which cuts a gap in one side of the film 32 in case of polypropylene film. Rotary cutter shown in Figure 5 is most preferable for such side cutter. The rotary cutter 78 is positioned in the middle of pairs of rollers and one side of progressing sheet paper 54. An upper and lower edges are joined to cut a gap in one side of the laminate film only when the laminated sheet papers 54 are placed between the edges.

Things are quite different in case the laminate film 32 is a polyvinyl chloride film which is easily elongated. Even if a small gap is cut in one side of polyvinyl chloride film, the gap will not grow up as in the case of polypropylene film. In order to use the polyvinyl chloride film for laminate film 32, the cutter 76 shall be moved in the transverse direction of sheet papers 54 to cut a line of gap in the film.

Sheet papers 54 with gapped laminate film 32 are holded and tensed between pairs of rollers 72,74.

Such tensile strength is originated by setting periphery speed of the roller faster than that of the leading roller 72. Thereby, the tensile strength is intrantaneously added to the sheet paper 54 and roll film 32. Then, the roll film 32 is broken into every sheet papers 54. In this case, the roll film is endurable in its progressing direction. The film is broken at once it the transverse direction of progres sing sheet paper 54. Finally, every laminated sheet papers 54 are stocked on the table 80.

As described in detail, by method and apparatus according to the present invention, sheet papers whose margins are piled up one above another are laminated in succession, and then a gap is cut in the laminated film, and finally the film is tensed to break the film from the gap and every separated sheet papers are obtained. Thereby, laminating operation of sheet paper can extremely be automated without any mannual works. Efficiency of production can be greatly raised, as the laminating operation is essentially continuous operation. Further, any flaw is not at all generated on the film surface and finishing quality is much improved.

Many other applications and modifications are possible in relation to the present invention. The present invention is not limited to those shown and described hitherto.

Claims (9)

1. Method for laminating sheet paper com prising; process of successively supplying sheet papers, piling their margins up one above another, process of continuously laminating sheet papers with roll film coated with an adhesive, process of cutting a gap to the laminated film on sheet papers which were laminated, with their margins piled up one above another, and process of holding the laminated sheet papers between pairs of rollers, setting the gap in the middle of pairs of rollers, and the laminated sheet papers are tensed so that the laminated film will be broken from the gap and the laminated sheet papers are divided into every sheet.

2. A method according to claim 1, wherein a gap is cut at one side edge of the progressing laminate film.

3. A method according to claim 1, wherein a line of cut is drawn at right angles with the progressing laminate film.

4. Apparatus for laminating sheet paper comprising; means for successively supplying sheet papers, piling their margins up one above another, laminater for continuously laminating sheet papers by roll film which is coated with an adhesive, cutter for cutting a gap to the laminated film on sheet papers which were laminated with their margins piled up one above another, and pairs of rollers between which the laminated sheet papers are hold, setting the gap in the middle of said pairs of rollers, and the laminated sheet papers are tensed so that the laminated film will be broken from the gap and the laminated sheet papers are divided into every sheet.

5. An apparatus according to claim 4, wherein a side cutter is provided for cutting a gap at one side edge of the progressing laminate film.

6. An apparatus according to claim 5, wherein the side cutter is a rotary cutter.

7. An apparatus according to claim 4, wherein the cutter draws a line of cut at right angles with the progressing laminate film.

8. A method for laminating sheet paper substantially as herein described with reference to and as shown in the accompanying drawings.

9. An apparatus for laminating sheet paper substantially as herein described with reference to and as shown in the accompanying drawings.