GB2027392A

GB2027392A - Offset photogravure press

Info

Publication number: GB2027392A
Application number: GB7832375A
Authority: GB
Original assignee: Yakult Honsha Co Ltd
Current assignee: Yakult Honsha Co Ltd
Priority date: 1978-08-04
Filing date: 1978-08-04
Publication date: 1980-02-20
Also published as: GB2027392B

Abstract

Two or more printing cylinders 1, 2 engage in rotating relationship a transfer surface of a transfer (or blanket) cylinder 3 so as not to have a common contact area on the transfer surface. The printing cylinders successively transfer individual images with different colours to the transfer surface and transferred images are printed on a rotating container 4 having a circular cross- section and engaging the transfer cylinder to form an axially divided multi-colour impression. A first one of the printing cylinders may include at least a portion having no image formed on it and contacting that portion of the transfer surface- engaged by any of the remaining cylinders. <IMAGE>

Description

SPECIFICATION A combined photogravure and offset press This invention relates to a combined photogravure and offset press for printing simultaneously an axially divided multi-coloured image on an outer surface of a container having a circular cross-section.

Simultaneous polychrome printing is generally accomplished on each of a plurality of containers formed of plastics or the like according to a dry offset technique. The term "simultaneous polychrome printing" used herein refers to printing an image of several colours on matter to be printed by applying a corresponding plate to each of the matters only once but not printing the image with one colour on the matters and printing a second colour in overlapping relationship thereon after the lapse of a drying time.

Simultaneous polychrome printing according to the dry offset technique involves the multicoloured representation using printing of the fundamental colours according to tone printing and the divided multi-coloured printing in which different colours are printed in the independent forms on matters to be printed. In either case, the printing capacity is low in view of the mechanism by which the dry offset printing is effected. Also it requires a drying step as a secondary procedure.

On the other hand, there are known combined photogravure and offset systems as high speed printing systems but simultaneous polychrome printing according to these known systems is said to be presently impossible even though the printing would be of the divided multi-coloured type or of the colour tone printing multi-coloured type. This is because, a transfer image of a first colour formed on a blanket is peeled off the blanket by that stamping roll subsequently forming another transfer image of a second colour on the blanket. In order to avoid this peeling of the first colour image, attempts have been made to dispose a re-transfer cylinder between the blanket and the stamping roller, the re-transfer cylinder being higher in exfoliation than the blanket.However, the re-transfer cylinder utilised in the later stage interferes with the transfer image that has been formed previously on the blanket and inevitably damages that transfer image. This disadvantage of conventional simultaneous multi-coloured printing systems is enhanced as the number of colours increases.

It is an object of the present invention to provide an improved combined photogravure and offset printing press and more particularly to provide such a press for printing simultaneously a clear polychrome on containers at a high speed without stamping rolls involved interfering with a transfer image.

The present invention provides a combined multi-colour photogravure and offset press for printing an axially divided, multicoloured image on an outer surface of a container having a circular cross-section whilst the container undergoes rotational motion in engagement with a transfer cylinder, comprising a single transfer cylinder and a plurality of stamping rolls circumscribed with said transfer cylinder, a succeeding one of said stamping rolls being disposed at a position in which the same does not interfere with an image transferred to the transfer cylinder from a preceding one of said stamping rolls.

The invention will now be more particularly described with reference to the accompanying drawings, wherein: Figure 1 is a schematic side elevational view of one embodiment of a two colour-two division printing press according to the present invention; Figure 2 is a fragmentary schematic side elevational view illustrating the positional relationship between a blanket and stamping rolls of another embodiment of a two colour-two division printing press according to the present-invention, Figure 3 is a view similar to Figure 2 but illustrating one embodiment of a two colour-three division printing press according to the present invention; Figure 4 is a fragmental plan view of an embodiment of a two colour printing press according to the present invention;; Figure 5 is a fragmental schematic side elevational view illustrating the positional relationship between a blanket and stamping rolls of one embodiment of a three colour-three division printing press according to the present invention; Figure 6 is a view similar to Figure 5 but illustrating a modification of the arrangement shown in Figure 5; and Figure 7 is a view similar to Figure 5 but illustrating an embodiment of a three coiour-four division printing press according to the present invention.

Referring to Figure 1 there is shown therein a two colour-two division printing press in which stamping rolls 1 and 2 coated with inks having different colours respectively are disposed so as not to have a common transfer area on a transfer surface of a transfer or blanket cylinder 3. In such an arrangement the transfer of a first image is accomplished by the stamping roll 1 after which the stamping roll 2 effects the transfer of a second image. At that time, the second image is transferred without damaging the first transferred image. Thereby a two-coloured image axially divided into two portions is printed on a rotating container 1 engaging both the blanket cylinder 3 and an impression cylinder 5 undergoing rotation.

Modifications of the two-coloured printing press are shown in Figures 2 and 3 in which the stamping rolls 1' and 2' (Figure 2) or 1" and 2" (Figure 3) are disposed so as to have in part a common contact area on the transfer surface of the blanket cylinder 3' or 3". In this case, it is assumed that the first stamping roll 1' or 1" does not include an engraved portion from which an image is transferred to the common contact area. The arrangement of the stamping rolls 1" and 2" as shown particularly in Figure 3, permits the formation of two colour-three division printings.

Figure 4 shows a skeleton plan view of a two-colour printing press. In Figure 4 wherein an inking mechanism and others are not illustrated, a stamping roll 1"' transfers an image in a first colour to a transfer surface of a blanket cylinder 3"' after which a stamping roll 2"' transfers an image in a second colour to the transfer surface of the blanket 3"' so as to accord with the previously transferred image in view of the design. Thereafter a container 4' of circular cross section is fed between the blanket cylinder 3"' and the impression cylinder 5' to be printed with an axially divided two-colour image. After the printing, surplus quantities of inks are removed from the blanket cylinder 3"' by doctor rolls 6. The above operation is continuously repeated to print further containers 4", 4"' .. ... etcetera.

Figures 5 to 7 inclusive show the arrangements of the stamping rolls in a three-colour printing press. In Figure 5 three stamping rolls 7, 8 and 9 are disposed so as not to have a common contact area on the transfer surface of the blanket cylinder. In the arrangement illustrated, the stamping roll 7 transfers an image in a first colour after which the stamping roll 8 transfers an image in a second colour without damaging the image transferred to the blanket cylinder from the stamping roll 7. Subsequently, an image in a third colour is transferred by the stamping roll 9, without damaging the previously transferred images. Thus a three coloured image axially divided into three portions is printed on a container.

Figure 6 and 7 show modifications of the three-colour printing press. The arrangements illustrated are different from the arrangement shown in Figure 5 in that in Figures 6 and 7 the first stamping roll (which is designated by 7' in Figure 6 and 7" in Figure 7) and the two succeeding stamping rolls (which are designated by 8' and 9' in Figure 6, and by 8" and 9" in Figure 7) have partly common contact areas on the transfer surface of the blanket. In the latter case, the first stamping roll 7' or 7" must not have an ingraved portion from which the image is transferred on each of the common contact areas.

Therefore, the stamping roll 7' includes an engraved portion located on the upper part thereof alone and the stamping roll 7" includes engraved portions located on the upper and iower parts thereof alone. It will be appreciated that an arrangement such as shown in Figure 7 permits the formation of three colour-four division printings.

As above described, the present invention can effect axially divided multi-coloured printings with a high efficiency.

As an example, a two colour-two divisions printing press including the arrangement of stamping rolls such as shown in Figure 1 has been employed to print a two-coloured image on containers having a circular cross section and formed of polyethylene. The results of the printing is listed in the following Table I.

TABLE I

Printing Conditions Printing Speed 400 BTL.P.M. Results Ink Alcoholic Solvent Printed State Good Condition Viscosity Zahn cup No. 5, 14 sec. Secular Change No Operating One Hour Loss No Time

Claims

1. A combined multi-colour photogravure and offset press for printing an axially divided, multicoloured image on an outer surface of a container having a circular cross section whilst the container undergoes rotational motion in engagement with a transfer cylinder, comprising a single transfer cylinder and a plurality of stamping rolls circumscribed with said transfer cylinder, a succeeding one of said stamping rolls being disposed at a position in which the same does not interfere with an image transferred to the transfer cylinder from a preceding one of said stamping rolls.

2. A press as claimed in claim 1 , wherein two stamping rolls are circumscribed with said transfer cylinder.

3. A press as claimed in claim 2, wherein said two stamping rolls circumscribed with said transfer cylinder are disposed so as not to have a common contact area on a transfer surface of said transfer cylinder.

4. A press as claimed in claim 2, wherein said two stamping rolls are disposed so as to have a common contact area on a transfer surface of said transfer cylinder.

5. A press as claimed in claim 1, wherein three stamping rolls are circumscribed with said transfer cylinder.

6. A press as claimed in claim 5, wherein a second and a third one of said three stamping rolls circumscribed with said transfer cyiinder are disppsed so as to have a contact area common to a first one of said stamping rolls on a transfer surface of said transfer cylinder, and said third stamping roll is disposed so as to have no contact area common to said second stamping roll on said transfer surface of said transfer cylinder.

7. A press as claimed in claim 5, wherein said three stamping rolls circumscribed with said transfer cylinder are disposed so as not to have common contact areas on a transfer surface of said transfer cylinder.

8. A combined multicolour photogravure and offset press for printing an axially divided multicoloured image on a container having a circular cross-section substantially as herein described with reference to and as shown in any of Figures 1 and 4, or as modified by Fig. 2 or Fig. 3 or Fig. 5 or 6 or Fig. 7 of the accompanying drawings.