HK1112880A - Method of printing smoking article wrapper - Google Patents

Description

Method for printing smoking article wrapper

The present invention relates to a method of printing a smoking article wrapper in a smoking article manufacturing machine during the manufacture of a smoking article, a smoking article wrapper printing apparatus and a smoking article comprising a wrapper printed according to the method.

Typically, the wrapper of the smoking article (e.g. the paper of a cigarette) will have printing thereon, such as a logo, graphic or trademark of the cigarette in question.

Gravure printing is a commonly used printing method in magazines and the like, which allows for high quality printing of coppers or photographs. In gravure printing, printing ink is applied to a printing cylinder having a recessed pattern representing a text or image to be printed, and the printing ink is transferred to paper to be printed. Typical gravure printing presses have speeds of 200 m/min to 400 m/min. These high speed printers utilize a1 to 2 meter wide print substrate, such as a paper web or sheet.

As in commercial smoking article rod making machines, smoking article wrapper may be cut from a pre-printed paper web produced by gravure printing techniques and stored in roll form. In these machines, the wrapper is supplied from a storage roll and is wrapped longitudinally around the continuously formed tobacco rod. Thereafter, the wrapped tobacco rod is cut into individual cigarettes. However, when using pre-printed wrapper, it is difficult to cut the tobacco rod in register with the print on the wrapper, i.e. to cut the tobacco rod at the correct position so that the print is correctly located on the finished smoking article.

To avoid this problem, the cigarette industry prefers to print the smoking article wrapper in the smoking article rod making machine during the manufacture of the smoking article rod, i.e., "on-line" printing. Because the processing speed of smoking article rod making machines is very high, which is typically greater than 400 m/min, the printing technique used for this purpose is letterpress or flexography, in which a male mold is inked by rollers and is pressed onto the paper to be printed. These processes are disclosed in WO 2003/000497A 2, EP 1125737A 2, WO 1999/51439A 1, DE 19648567A 1 or GB 2100192B.

Although these on-line letterpress or flexography techniques allow more or less precise alignment of the graphics or logos to be printed onto the packaging material, their printing quality is relatively poor. The photographic halftone image does not reproduce properly and cannot be printed uniformly over a large area. Moreover, the lead stamp tends to become dirty relatively quickly, and the cleaning procedure is a time-consuming task involving disassembly of the printing unit, which typically takes two to three hours.

It is an object of the present invention to provide the possibility of printing smoking article wrapper material in a cost-effective manner with high quality.

This problem is solved by a method of printing a smoking article wrapper according to claim 1 and by a smoking article wrapper printing apparatus according to claim 16. Claim 24 relates to a smoking article comprising a wrapper printed according to the method of the preceding claim. Advantageous variants of the invention can be derived from the dependent claims.

In the method according to the invention, the smoking article wrapper is printed in the smoking article manufacturing machine during the manufacture of the smoking article, preferably in the smoking article rod manufacturing machine during the manufacture of the smoking article rod. The printing technique used is gravure printing.

Gravure printing allows a much higher level of print quality. For example, it can print large areas of color uniformly, or can correctly reproduce copperplate images, as compared to conventional letterpress or flexography. Because gravure printing techniques are used on-line in smoking article rod making machines, there are no problems with misalignment of printed objects that occur in pre-printed wrappers. In the present invention, the printing speed can be much higher than that of commercial gravure presses (200 m/min to 400 m/min). In order to adapt the printing process to the operating speed of a fast smoking article rod making machine, it becomes possible with the method according to the invention to print speeds of, for example, 720 m/min.

Preferably, the smoking article wrapper is supplied from a storage roll, fed to the printing cylinder by a system of guide rollers and tension rollers, and, after printing, longitudinally wound on a rod processed by the smoking article rod making machine. The wrapped rod is cut into individual smoking article rod pieces in register with the printing process. In a subsequent step, these cigarettes may be provided with filters or the like. The method may be carried out in a conventional smoking article rod making machine, for example a conventional cigarette making machine. Typically, the width of the wrapper supplied from the storage roll is about a few centimeters, such as 26.75 meters, i.e. the circumference of a typical cigarette plus the width of the adhesive seam of the wrapper. Thus, the gravure printing technique is suitable for narrow print substrates, as compared to 1 to 2 meters wide print substrates used in typical high speed gravure printing presses.

In an advantageous variant of the invention, the printing agent, such as printing ink, is supplied onto the intaglio printing cylinder through a pressurized chamber which contacts the printing cylinder through a seal, such as a sliding seal. Preferably, the printing agent is pumped through the pressurized chamber, e.g. continuously pumped. The design is very compact, reliable in operation and not prone to becoming dirty. In particular, a cleaning liquid may be pumped through the chamber in a separate cleaning cycle in order to remove any stains within the chamber and on the surface of the printing cylinder. The cleaning procedure is fast, it takes, for example, only 7 minutes, which is much shorter than the time required to clean a conventional letterpress printing apparatus.

In the method according to the invention, more than one intaglio printing cylinder may be used, wherein different printing agents are assigned to different printing cylinders. For example, three gravure printing cylinders may be used for three-color printing. In this case, three images, each having a different base colour, may be printed at the same location on the smoking article wrapper to obtain a self-colour image. Furthermore, four or more printing cylinders can be advantageously used for a plurality of printing colours and different printing agents.

Preferred printing inks are water-soluble printing inks. Water-based dye ink systems can be used in food grade quality and are approved. It is also contemplated to use high gloss metallic ink systems such as gold.

However, the printing agent is not limited to the printing ink. The process according to the invention is also suitable for printing agents of very different types, for example for hardeners or combustion improvers (preferably flame retardants) or flavourings. In principle, these ingredients may be added to the packaging material during or after the manufacturing of the packaging material. However, the in-line printing technique has the great advantage that the printing agent can be applied in a certain pattern or in certain locations, so that, for example, the fire retardant is active after the cigarette has been smoked to a predetermined length, or the flavour is released after the cigarette has been smoked to a predetermined stage. Flame retardants are disclosed, for example, in US 4619278A, US 4452259A, US 4622983A, EP 0671505B 1, EP 1123665 a2, WO 2001/078471 or EP 0325920, and in general, are well known in the art.

The term "smoking article wrapper" is to be understood in a broad sense. A typical example is cigarette paper, in which case the smoking article rod making machine is a cigarette making machine. Another example is a tobacco roll wrapper, which is not smokable. In this case, the smoking article rod making machine is used to make a tobacco roll having a tobacco rod surrounded by a non-smokable tobacco roll wrapper. The product cannot be smoked like a cigarette, but rather its tobacco content must be transferred from the tobacco roll wrapper into a smokable cigarette wrapper or a pre-formed sleeve. Other examples of related smoking articles are cigars with wrappers and/or wrappers, cigarillos with wrappers and/or wrappers, cigarette paper tubes or portioned fine cut tobacco units, also cigarette filter tubes, etc.

The method according to the invention may also be applied in a smoking article paper making machine during the manufacture of individual smoking article papers, preferably in a machine for making paper booklets comprising cigarette paper. These cigarette papers are used by those consumers who make ("roll") cigarettes from a tobacco source and the individual cigarette papers provided in a booklet containing folded and bound together sheets of cigarette paper. A machine for making these booklets is disclosed in EP 0165747B 1, for example. It is advantageous when the cigarette papers are folded into bundles and packed into paper booklets immediately after they have been printed by the method according to the invention.

The objects printed in the gravure printing process are not limited to simple forms such as characters or printing-like figures, but may include all kinds of images, photographs, figures, designs, and the like. Regular patterns can also be envisaged, for example in decorative designs or for technical reasons (e.g. desired positions with respect to hardeners, flame retardants or flavourings used by the printing technique).

The smoking article wrapper printing apparatus according to the present invention is used in a smoking article rod making machine during the manufacture of smoking article rods and is a gravure printing device. Typically, existing commercial smoking article rod making machines are equipped with such printing devices without major modifications. The smoking article wrapper printing apparatus may also be used in a smoking article wrapper manufacturing machine during the manufacture of individual smoking article wrappers.

Preferred variants of the apparatus have already been described above in the discussion of the method according to the invention. In particular, when the apparatus comprises a pressurized chamber that contacts the intaglio printing cylinder by means of a sliding seal, the cleaning liquid may be pumped through the pressurized chamber in a separate cleaning cycle. The printing position on the smoking article wrapper in register with the operation of the smoking article rod making machine, in particular with its cutting means, may be controlled by control means comprised in the printing apparatus.

Hereinafter, the present invention will be described in more detail by examples. In the drawings:

figure 1 shows a schematic view of a printing apparatus for monochrome printing in a smoking article rod making machine according to the present invention; and

figure 2 shows a schematic view of another embodiment of a printing apparatus for tri-colour printing in a smoking article rod making machine according to the present invention.

Figure 1 is a schematic representation of a region in a smoking article rod making machine 1 in which smoking article wrapper is printed and wound onto a rod processed by the smoking article rod making machine 1. In the present embodiment, the smoking article rod making machine 1 is a conventional cigarette making machine for making tobacco rods, but in order to print text or graphics on smoking article wrapper (i.e. cigarette wrapper), a different printing device is used instead of a conventional letterpress or flexographic printing unit.

Smoking article wrapper (in this embodiment, the width of the cigarette paper is 26.75 meters) is supplied from the storage roll 2. The unfolded packaging material, indicated by reference numeral 3, is fed to a printing device 6 by a system 4 of guide rollers and tension rollers, which printing device 6 will be described in more detail below. After printing and leaving the printing apparatus 6, the packaging material 3 passes over a further roller 7 and through a guide 8, on which guide 8 the packaging material enters a conveyor 9.

On conveyor 9, wrapping material 3 encounters the tobacco rod processed by machine 1 and is longitudinally wound onto the tobacco rod, as is known in the art. The wrapped rod is then cut into individual smoking article rod pieces, which may be further processed (e.g., provided with filters, etc.).

In the present embodiment, guide 8 comprises control means which detect the position of the text and graphics on (stationary) endless wrapper 3 in order to control the cutting machine which cuts the rods into individual smoking article rod pieces. In this way it is ensured that the text or graphics on the wrapper of the finished cigarette is in the correct position.

The printing apparatus 6 is different from a conventional letterpress or flexographic printing unit. It comprises a gravure printing cylinder 10, a counter-pressure cylinder 12 and a chamber 14. Further components are guide and tension rollers, drives, etc., which are generally familiar to the person skilled in the art and need not be described in detail.

The printing cylinder 10 is a gravure printing cylinder manufactured according to a method known in the art of gravure printing. It is inked through the chamber 14, see below. As wrapping material 3 travels between print cylinder 10 and counter-pressure cylinder 12, the images, text, etc. provided on print cylinder 10 are printed onto wrapping material 3.

In the area facing print cylinder 10, chamber 14 has an opening sealed to print cylinder 10 by a sliding seal attached to the edge of the opening. In addition, chamber 14 has an inlet and an outlet (not shown in FIG. 1) that connect chamber 14 to a source of printing ink via a conduit. The chamber 14, the printing ink supply, the conduit and the pump together form a closed circuit which is pressurized by the pump. Thus, printing ink circulates through the circuit and is transferred to the print cylinder 10 through the chamber 14. A portion of the sliding seal of chamber 14 cleans the surface of printing cylinder 10 (except for the concavity to be inked) from transferring excess ink onto packaging material 3.

In this embodiment, the pressure and temperature of the chamber 14 and inking circuit are monitored by sensors.

Printing device 6 can be easily cleaned when chamber 14 is disconnected from the ink source and connected to the cleaning liquid source, and when cleaning liquid is drawn through chamber 14 while printing cylinder 10 is rotating. This eliminates the need to disassemble the printing apparatus 6, thus saving considerable time and cost.

In one example, the printing device 6 operates at speeds up to 730 meters per minute in the cigarette making machine 1 to print large surface area cigarette logos. With rotary lead presses, this style of marking typically has very poor print quality due to the lack of ink on the surface of the mold, resulting in an incomplete image in which portions of multiple printed areas are missed. However, the printing device 6 produces very clean, sharp and solid prints at full speed, with test speeds up to 730 m/min.

In another example, very fine pictures containing photographic copper plate images are printed in register with the cutter head of the cigarette making machine 1 at speeds up to 730 m/min. Some of these designs cover substantially the entire length of the finished cigarette. In another example, photographs are printed over the same speed range. These results are not possible with conventional rotary cliche systems.

In the above-described embodiment, the printing agent supplied through the chamber 14 is printing ink. In another example, flavoring agents in a range of viscosities may be printed directly onto a wrapper 3, such as cigarette paper, just prior to cigarette manufacture. These flavors may be retained because the cigarettes are packaged shortly thereafter. Furthermore, the flavoring agent may be printed onto the cigarette paper in any desired pattern, for example, to release a certain flavor at a desired time during smoking.

In another example, the combustion improver can be printed directly onto cigarette paper within a range of viscosities immediately prior to cigarette manufacture.

Figure 2 shows another embodiment of a smoking article wrapper printing apparatus for use in a smoking article rod making machine. Since the embodiments in fig. 1 and 2 are similar, the same reference numerals are used in both figures to denote mutually corresponding components.

However, in fig. 2, the printing apparatus (indicated with 6') allows three-color printing. To this end, it comprises three cells, one for each elementary color, comprising a gravure printing cylinder 20, 20 ' and 20 ", a counter-pressure cylinder 22, 22 ' and 22" and a chamber 24, 24 ' and 24 ", respectively. Each unit functions as described above with respect to the embodiment according to fig. 1.

It is also conceivable to combine printing units for processing printing inks with printing units for processing other printing agents, such as hardeners (e.g. starch), flame retardants, flavourings and/or fragrance precursors.

A great advantage of printing the flavourant or other printing agent during the manufacture of the smoking article or at the end of the process is that there is little or no loss of flavourant or printing agent. For example, when applying flavors with the method according to the invention in order to replace flavoring tobacco in a conventional flavoring drum, complicated washing steps can be avoided, especially when changing flavor batches.

Claims (27)

1. A method of printing a smoking article wrapper in a smoking article manufacturing machine (1) during the manufacture of smoking articles, characterised in that the printing technique used is gravure printing.

2. A method as claimed in claim 1, wherein the method is applied within a smoking article rod making machine (1) during the manufacture of smoking article rods.

3. A method as claimed in claim 2, wherein smoking article wrapper (3) is supplied from a storage roll (2), the wrapper (3) is fed to at least one printing cylinder (10; 20, 20', 20 ") by means of a system (4) of guide and tension rollers, and after printing, the wrapper (3) is longitudinally wound onto a rod processed by the smoking article rod making machine (1) and the wrapped rod is cut into individual smoking article rods in register with the printing process.

4. A method according to claim 2 or 3, wherein the smoking article wrapper (3) is a wrapper selected from the group consisting of: cigarette paper, cigar wrapper, cigarillo wrapper, cut tobacco unit wrapper, non-smokable tobacco roll wrapper, cigarette filter tube wrapper.

5. A method according to claim 1, wherein the method is applied in a smoking article wrapper making machine, preferably a machine for making paper booklets containing cigarette paper, during the manufacture of each individual smoking article wrapper.

6. The method according to one of claims 1 to 5, characterized in that the printing agent is supplied onto the intaglio printing cylinder (10; 20, 20 ', 20 ") through a pressurized chamber (14; 24, 24', 24"), said pressurized chamber (14; 24, 24 ', 24 ") contacting said printing cylinder (10; 20, 20', 20") through a seal.

7. The method according to claim 6, characterized in that the printing agent is pumped, preferably continuously pumped, through the pressurizing chamber (14; 24, 24', 24 ").

8. The method according to one of claims 1 to 7, characterized in that at least two different gravure printing cylinders (20, 20 ', 20 ") are used, wherein different printing agents are assigned to the different printing cylinders (20, 20', 20").

9. The method according to claim 8, characterized in that three gravure printing cylinders (20, 20', 20 ") are used for the trichromatic printing.

10. Method according to one of claims 1 to 9, characterized in that the printing agent is a printing ink, preferably a water-soluble printing ink.

11. Method according to one of claims 1 to 10, characterized in that the printing agent is a hardener.

12. The method according to one of claims 1 to 11, characterized in that the printing agent is a combustion improver, preferably a flame retardant.

13. The method according to one of claims 1 to 12, characterized in that the printing agent is a flavouring agent.

14. The method according to one of claims 1 to 13, characterized in that the object printed in the printing process comprises at least one of the following forms: images, photos, figures, characters, patterns and designs.

15. The method of one of claims 1 to 14, wherein the printing speed is greater than 400 m/min.

16. A smoking article wrapper printing apparatus for use in a smoking article rod making machine (1) during the manufacture of smoking article rods or for use in a smoking article paper making machine during the manufacture of individual smoking article papers, characterized in that the printing apparatus (6; 6') is a gravure printing device.

17. The apparatus according to claim 16, wherein a pressurized chamber (14; 24, 24 ', 24 ") contacts the gravure cylinder (10; 20, 20', 20") through a seal, and a printing agent can be supplied onto the gravure cylinder (10; 20, 20 ', 20 ") through the pressurized chamber (14; 24, 24', 24").

18. The apparatus according to claim 17, wherein the pressurizing chamber (14; 24, 24 ', 24 ") is adapted for the printing agent pumped through the pressurizing chamber (14; 24, 24', 24"), preferably continuously.

19. An apparatus according to claim 18, characterized in that the apparatus (6; 6 ') is adapted to be cleaned by pumping cleaning liquid through the pressurizing chamber (14; 24, 24', 24 ") in a separate cleaning cycle.

20. An apparatus as claimed in any one of claims 16 to 19, wherein control means (8) are provided, said control means (8) being adapted to control a printing position on said smoking article wrapper (3) in alignment with the operation of said smoking article rod maker (1) or smoking article web maker.

21. The apparatus as claimed in one of claims 16 to 20, characterized in that at least two different intaglio printing cylinders (20, 20 ', 20 ") are provided, wherein different printing agents are assigned to the different printing cylinders (20, 20', 20").

22. An apparatus as claimed in claim 21, characterized in that three intaglio printing cylinders (20, 20', 20 ") are provided for three-colour printing.

23. Apparatus according to one of claims 16 to 22, characterized in that the apparatus is adapted to printing speeds of more than 400 m/min.

24. A smoking article comprising a wrapper printed according to the method of one of claims 1 to 15.

25. The smoking article of claim 24, wherein the smoking article is an article selected from the group consisting of: cigarettes with cigarette paper, cigars with wrapping and/or cladding, cigarillos with wrapping and/or cladding, cigarette paper tubes, portioned fine cut tobacco units, cigarette filter tubes.

26. A smoking article according to claim 24, wherein the smoking article is a tobacco roll having a non-smokable tobacco roll wrapper, the tobacco roll being provided for transfer of its tobacco content from the tobacco roll wrapper into a smokable cigarette wrapper or a pre-formed sleeve.

27. A smoking article according to claim 24, wherein the smoking article comprises a cigarette paper, preferably a paper booklet comprising individual cigarette papers bound together.