WO2006048022A2

WO2006048022A2 - An apparatus for printing images on the annular sidewall of a formstable plastics container

Info

Publication number: WO2006048022A2
Application number: PCT/DK2005/000708
Authority: WO
Inventors: Michael Jeppesen; Tom Jensen; Jørgen SKREE
Original assignee: Superfos A/S
Priority date: 2004-11-08
Filing date: 2005-11-07
Publication date: 2006-05-11
Also published as: WO2006048022A3

Abstract

The invention relates to an apparatus for printing images on the round-going sidewall of a dimensionally stable plastics container (1), comprising means for securing the container (1) and for allowing rotation of the container (1) about the longitudinal axis of the container (1), preferably about the axis of symmetry (61) of the container (1), during the printing procedure; and application means (25) for securing and rotating a colour transfer cloth (28, 28’) about an axis (26) such that the colour transfer cloth (28, 28’) touches the round-going sidewall of the container (1). The invention is characterised in a first cliché holder (50) for securing and rotating a first cliché (52) about an axis (51) in such a manner that the first cliché (52) touches a first area (D) of the colour transfer cloth (28, 28’) for application of colour material (5); at least a further cliché holder (40, 30) for securing and rotating a respective cliché (42, 32) about an axis (41, 31) in such a manner that the further cliché (42, 32) touches a second area (E) of the colour transfer cloth (28, 28’) displaced along the direction of advancement of the colour transfer cloth (28, 28’) for application of colouring material (10); means (56, 58) for transferring a first colouring material to the first cliché holder and means (36, 38; 46, 48) for transferring a respective colour to the cliché (32, 42) on the further cliché holder(s) (40, 30); that the apparatus (20) is configured such that the container (1) is rotated more than once about said longitudinal axis (61); and that the total length of the colour transfer cloth is adapted to be such that a print on the container (1) of the fires area (D) and a print on the container (1) of the second area (E) can be caused to overlap by said rotation of the container (1).

Description

An apparatus for printing images on the round-going sidewall of a dimensionally stable plastics container

The present invention relates to an apparatus for printing images on the round-going, ie peripheral, sidewall of a dimensionally stable plastics container.

Apparatuses of this kind comprise a holder for securing the container in such o* manner that it can rotate about its axis of symmetrv .luring the printing procedure, and a colour transfer cloth rotating about an axis, said colour transfer cloth being in contact with the round-going sidewall of the container during rotation of the container for application of colour on the container. Moreover a number of cliche cylinders will be provided for rotating respective cliches that touch the colour transfer cloth for application of colour on the colour transfer cloth in accordance with the image it is desired to print on the container.

For production technical reasons colouring materials are used for the printing of images onto plastics containers that cure or set rapidly upon irradiation with UV-light. Usually images printed by means of that kind of colouring materials are translucent, which means that the quality of the image as experienced by the viewer can be affected negatively by the colour of the contents of the container sitting behind it when the container is transparent or of the container's own colour when the container is not transparent.

By the apparatus according to the invention as defined in claim 1 , it is possible to improve the quality of the printed image in a simple manner. More specifically this is accomplished in that the apparatus is configured for applying a first layer of colouring material, which may eg be white, onto the container during a first rotation of the container; and that a further layer of one or more colouring material(s) is subsequently applied precisely on top of the field(s) of the container where the first layer was applied by an immediately following rotation of the container without the container being otherwise moved in the apparatus.

According to a preferred embodiment the apparatus comprises a UV-lamp irradiating the container simultaneously with the container being rotated the first time with a view to drying or curing/setting of the first layer of colouring material, said apparatus being configured for preventing an irradiation of the colour transfer cloth from the UV-lamp, which could cause curing/setting of colouring material not yet applied onto the container.

According to a further embodiment the container is rotated twice in the apparatus during the application process.

The invention will now be described in further detail with reference to a currently preferred embodiment.

Figure 1 a shows a dimensionally stable plastics container, and Figures 1 b-1e show two containers as shown in Figure 1a provided with a image applied by means of the apparatus according to the invention;

Figure 2a is a sketch showing the apparatus according to the invention, seen in a lateral view;

Figure 2b is a sketch showing the apparatus from Figure 2a, seen in the direction of the arrow I;

Figures 3a-3d and 3e shows examples of cliches and a colour transfer cloth, respectively, suitable for use in the apparatus according to the invention for forming the image shown in Figure 1c; and Figures 4a-4d and 4e show examples of cliches and a colour transfer cloth, respectively, suitable for use in the apparatus according to the invention for forming the image shown in Figure 1 e.

Figure 1a shows a transparent and dimensionally stable plastics container of an otherwise conventional type with a sidewall that extends around a longitudinally extending axis of symmetry that defines a longitudinal axis for the container perpendicular to the container bottom. In other words the container 1 is rotationally symmetrical about a longitude -illy extending axis, at least in the area adjacent the sidewall. Whether the container 1 is transparent or not is really of no consequence to the present invention, albeit when transparent containers are concerned, use of the apparatus according to the invention is associated with particular advantages.

The shown container 1 is slightly conical, but may have the shape of a straight cylinder. Containers 1 of this type are typically used eg within the foodstuffs industry, wherein said container is provided with a print on the external surface; filled with a product; provided with a lid, and supplied to a sales outlet. For instance, the container 1 may have a height of 10 cm and a mean diameter D of 6 cm, and the applied text indicates the contents of the container 1. The container 1 has a mean circumference corresponding to π D.

In Figures 1 c and 1 e, the external surface of the container is shown provided with printed images 10 comprising eg a text and a drawing. For practical reasons, the following disclosure will generally refer to application of an "image" onto the container, bearing in mind that this term is intended to comprise any kind of printed indication on the external surface of the container. For reasons of ease of production, colouring materials that cure quickly upon irradiation with UV-light are used for the application of images onto plastics containers. Usually printed images formed from that kind of colouring material are translucent, meaning that the quality of the images as experienced by the viewer can be adversely affected by the colour of the contents of the container 1 sitting behind it, when the contai ner 1 is transparent, or by the colour of the container itself when the container 1 is not transparent. In both cases it may therefore be of interest to provide the container 1 with a base co'our, ie a first layer of colouring material that forms a contrast whereby the image is offset more distinctly. Moreover, for instance when the container 1 is not transparent, it by be of interest eg to apply the same image twice, whereby two layers of one or more colouring matehal(s) is/are applied on top of each other.

In Figures 1 b and 1d the container 1 is shown provided with one and three fields 5, respectively, of a base colour, which is preferably white and being applied onto the container 1 by the apparatus in accordance with the present invention immediately prior to the application of the colours partaking in the image 10. In some cases the base colour in itself may also be visible following application of the image, see Figure 1c, where it is shown that field 5 formed by the base colour covers a greater area than the fields 10 of colour that form the image as such. Figure 1d shows, by comparison with Figure 1 e, an opposite scenario where the base colour is applied in fields 5 precisely where the colour fields 10 that form the image are subsequently applied, as shown in Figure 1 e.

According to the invention it is enabled, in a simple manner and with a high degree of accuracy, to apply the colouring material for the image 10 precisely on the area(s) 5 of the container 1 where the base colour is applied. Figure 2a shows that an apparatus 20 according to the invention comprises a central, rotating cylinder 25, on which a number of cloths 28, 28' are arranged at a mutual distance A that will be described in further detail with reference to figures 3e and 4e. Moreover, the apparatus 20 co mprises a number of rotating cliche-holders in the form of cliche-cylinders 30, 40, 50, each of which carries a respective cliche 32, 42, 52 which is shown with exemplary relief-patterns in figures 3a-3c and in figures 4a-4c. The number of cliche-cylinders depends on the number of colours included in the image on the container 1 ; and Figure 2a shows a further cliche-cyiinder 150 which will not be disclosed in further detail; rather it will be used to form the image shown in Figures 1c and 1e.

During the rotation, the respective cliches of the cliche-cylinders 30, 40, 50 each touches a respective rotating colour cylinder 36, 46, 56, whose surface is supplied with colouring material from a respective colour receptacle 38, 48, 58. Cylinder 25 rotates about an axis of rotation 26 which is preferably fixed and in parallel with the axes of rotation 31 , 41 , 51 for the cliche-cylinders 30, 40, 50.

The apparatus 20 also comprises a number of rotatable mandrels 60, one of which is shown in Figure 2a. The mandrel 60 shown in Figure 2a carries a container 1 that was just taken to the shown position in front of the central cylinder 25 and onto which fields 10 of colour are to be applied that form the image on the container 1. The container 1 is received in such a manner on the mandrel 60 that the container 1 will rotate along with the mandrel 60 about an axis 61 that coincides with the longitudinally extending longitudinal axis of the container 1 which, in the present circumstances, is an axis of symmetry and which is also designated by reference numeral 61.

More specifically the mandrel 60 is journalled on a rotating mand rel support 100 shown in Figure 2b, wherein a new, unmarked container is eg taken onto the mandrel 60' which is, at all times, at the top, simultaneously with the container 1 being in Figure 2a applied with the base colour and the colours that are used in the image as such.

The procedure as such of applying print to the container 1 will be described below. At this point, however, it is noted that, fol lowing finished application of a image onto the container, the mandrel support 100 will turn clockwise about the axis of rotation 101 that extends perpendicular to the axis of rotation 26 of the central cylinder 25, following which the container 1 is released from the mandrel 60 and is optionally taken to a not shown station, where the container is exposed to UV-light in order to irradiate and cure the colouring materials that constitute the image 10 on the container 1 , if necessary.

Figures 3a-3c show exemplary cliches for use in the apparatus 20. Cliches 32, 42, 52 are flat and each has a first area B with a length x, and a second area C which also has the length x. length x corresponds to the circumference of the container 1. Thus, cliches 32, 42, 52 have a length 2x, and that length corresponds to twice the circumference of the container 1 and, as it is, also to the circumference of cylinders 30, 40, 50. The width of the cliches usually corresponds to maximally the height of the container 1.

The first area C of cliches 32, 42 has portions 10', 10" that are in relief and which are, during operation of the apparatus 20, to be provided with the respective colour or diestuff that is to be a part of the image and is hence to produce a respective coloured field 10 on the circumference of the container 1. The second area B of the cliches 32, 42 is blank and hence it does not take up any colour from the respective colour cylinder.

In the second area B the cliche 52 has a po rtion 5' which is in relief and whose shape corresponds to field 5 with base colour shown in Figure 1b, whereas the first area C of the cliche 52 is blank. Figure 3e shows the circumference of a flat rubber cloth 28 which is secured to the cylinder 25 and being of the type that is usually a part of offset printing equipment. The cloth 28 has two areas D, E each of which has a length x, and the length of the cloth 28 thus corresponds to twice the circumference of the container 1 or to twice the mean circumference of the container 1 , if the container 1 is conical as shown in Figure 1 a.

In operation the apparatus 20 rotates all cylinders an-! the container 1 with the same speed along the periphery. When the cylinder 25 rotates, the cloth 28 touches the cliche 52 which is secured to the rotating cylinder 50, and then the subsequent rotating cliches 42, 32. In this manner area D of the cloth 28 is provided with a field of a base colour whose shape corresponds to the desired field 5 on the container 1. The subsequent area E of the cloth 28 is, by the further turning of the cylinder 25, successively touched by portions 10', 10" on cliches 42, 32, whereby the cloth will finally carry the final colour image in negative and a single-colour field that corresponds to the desired field 5 on the container as shown in Figure 3e.

It will be understood that, when the cloth 28, 28' touches the rotating container 1 in the area 80, the base colour is first applied by the first rotation of the container 1 , the image 10 being applied by the subsequent rotation of the container 1. By suitable matching of the arrangement of the motives 5, 10, 10 on cloth 28, 28', it becomes possible to ensure that the image 10 is applied precisely on the desired location relative to the field 5, including precisely over a field 5 with a shape that corresponds precisely to the shape of the image 10 as shown in Figure 1 e. By the latter process a system of cliches is used as shown in Figures 4a-4d.

Behind the mandrel 60, a UV-lamp 70 is arranged that irradiates the container 1 on the container 60 with a view to drying or curing of applied base colour simultaneously with the container being rotated the first time. In front of the mandrel 60 a shield 72, 74 is configured that ensures, to the widest extent possible, that no kind of drying occurs of the colouring material on the area E of the colour transfer cloth 28, 28' when that area E approaches the area 80 near the lamp 70, while the base colour is being applied to the container 1. Albeit the container 1 is preferably taken to another UV-lamp for drying of the image colouring material, it may in some cases be desirable to also irradiate the container 1 , while it rotates the second time.

Even though the cliche cylinder 50 producing the field 5 with the base colour on the colour transfer cloth 28, 28' is shown in Figure 2a as the second cylinder to be met by the colour transfer cloth 28, 28' after the shield 74 during the rotation of the cylinder, nothing prevents the cliche 52 in question from being arranged on a cylinder located after or between the cliche cylinders 30, 40 that apply colour to area E of the colour transfer cloth 28, 28'. It will also be obvious that the speed of rotation of the individual cylinders and of the mandrel 60 must be suitably matched to provide the desired result.

It is shown in figures 3a-3d that the first and second area B, C of the cliches have the same length x; however, nothing prevents the area C from having another expanse y, eg a shorter expanse. The latter will be relevant in case the image to be applied is such that it is not necessary to rotate the image two full rotations about its axis. Moreover, nothing prevents the cliches and in particular the colour transfer cloth from being configured such that areas B and C, D and E, respectively, are joined, albeit it would lead to the simplest solution.

Finally it should be mentioned that, without departing from the invention, the invention can be applied for performing printing on containers with a round- going sidewall that has an oval or square course, seen from above, ie where the sidewall is not rotationally symmetrical about the longitudinal axis of the container, which would, however, typically constitute an axis of symmetry. In those cases a suitable configuration of the mandrel support 100 may conveniently be provided, enabling the printing procedure to take place by a simultaneous translation of the mandrel support 100 or of the mandrel support 60. It should also be mentioned that nothing prevents the printing procedure according to the invention from being exercised simultaneously with rotation and translation of the container 1 along the colour transfer cloth 28, 28'.

Claims

C l a i m s

1. An apparatus for printing images on the round-going sidewall of a dimensionally stable plastics container (1 ), comprising • means for securing the container (1) and for allowing rotation of the container (1 ) about the longitudinal axis of the container (1 ), preferably about the axis of symmetry (61 ) of the container (1 ), during the printing procedure;

• application mean¹- (25) for securing and rotating a colour transfer cloth (28, 28') about an axis (26) such that the colour transfer cloth (28, 28') touches the round-going sidewall of the container (1 ), characterised in

• a first cliche holder (50) for securing and rotating a first cliche (52) about an axis (51 ) in such a manner that the first cliche (52) touches a first area (D) of the colour transfer cloth (28, 28') for application of colour material (5);

• at least one further cliche holder (40, 30) for securing and rotating a respective cliche (42, 32) about an axis (41 , 31 ) in such a manner that the further cliche (42, 32) touches a second area (E) of the colour transfer cloth (28, 28') displaced along the direction of advancement of the colour transfer cloth (28, 28') for application of colouring material (10);

• means (56, 58) for transferring a first colouring material to the first cliche holder and means (36, 38; 46, 48) for transferring a respective colour to the cliche (32, 42) on the further cliche holder(s) (40, 30);

• that the apparatus (20) is configured such that the container (1 ) is rotated more than once about said longitudinal axis (61 ); and

• that the total length of the colour transfer cloth is adapted to be such that a print on the container (1 ) of the first area (D) and a print on the container (1 ) of the second area (E) can be caused to overlap by said rotation of the container (1 ).

2. An apparatus according to the preceding claim, characterised in that a UV-lamp (70) irradiating the container (1 ) simultaneously with the container (1 ) being rotated the first time about said longitudinal axis (61) with a view to drying or curing of the print of the first area (D) of the colour transfer cloth (28, 28').

3. An apparatus according to the preceding claim, characterised by means (72, 74), by which an irradiation of the colour transfc " cloth (28, 28') by the UV-lamp (70) is essentially or fully prevented.

4. An apparatus according to any one of the preceding claims, characterised in that the means for securing the container (1 ) comprises a device (1 O0) rotating about an axis (101 ) and provided with holders (6) for containers (1 ) protruding radially from the axis (101 ).

5. An apparatus according to any one of the preceding claims, characterised in that the first cliche (52) comprises an area (B) with portions (5') that are in relief and onto which, during operation of the apparatus (20), colouring material is applied which is to be applied onto the container (1 ) by a first rotation thereof, and a blank area (C) which is displaced in the longitud inal direction of the cliche (52).

6. An apparatus according to any one of the preceding claims, characterised in that the further cliche (32, 42) comprises an area (C) with portions ( 10') that are in relief and onto which, during operation of the apparatus (20), colouring material is applied which is to be applied onto the container (1 } by the subsequent rotation thereof, and a blank area (B) which is displaced in the longitudinal direction of the cliche (52).

7. An apparatus according to any one of the preceding claims, characterised in that the colour transfer cloth (28, 28') is a unitary stri p of a soft material.

8. An apparatus according to any one of the preceding claims, characterised in that the cliches (32, 42, 52) are a strip of a coherent material.

9. An apparatus according to any one of the preceding claims, characterised in that the container (1 ) is UV-irradiated separately following removal of the container from the means for securing the container (1 ).

10. An apparatus according to any one of the preceding claims, characterised in that the container (1 ) is rotated two full rotations.