GB2026947A - A rotary offset photogravure press - Google Patents

Abstract

A multicolour rotary offset photogravure press comprises a rotary transfer cylinder having a periphery consisting of transfer surface sections which are fixed, e.g. 22a-22f, or retractable e.g. 20a-20f. During the rotation of the transfer cylinder, photogravure rollers e.g. 36, 38 transfer separate colour images to respective transfer surfaces, a surface already carrying an image being temporarily retracted when it passes a subsequent photogravure roller. Container 10 receives combined images from both the fixer and retractable surfaces. The number of retractable surfaces for any one combined image is a minimum of one less than the number of colours; a transfer cylinder may be capable of transferring a plurality of combined images in any one rotation e.g. six containers 10 may each receive a two-colour image. <IMAGE>

Description

SPECIFICATION A rotary photogravure and offset press This invention relates to a combined multicolour rotary photogravure and offset press for printing a polychrome image on a container having a circular cross section.

The present invention provides a combined multi-colour rotary photogravure and offset press for a combined multicolour rotary photogravure and offset press for printing an image including divided portions in multicolour on an outer surface of a container having a circular cross-section, comprising a rotary transfer cylinder having a transfer surface which includes a plurality of transfer surface sections one for each of different colours imparted to divided image portions respectively, means for disposing the container to be printed in rotational engagement with the transfer surface of the transfer cylinder, a plurality of stamping photogravure rolls disposed in rotational engagement with the transfer surface of the transfer cylinder and having respective image portions formed thereon to correspond to the divided image portions respectively, the stamping rolls being assigned to the transfer surface sections respectively so that each of the stamping rolls transfers the image portion formed thereon to the assigned transfer surface section when opposed to the same during the rotational movement of the transfer cylinder, and support means for supporting at least all but one of said plurality transfer surface sections for retraction radially inwardly within the transfer cylinder, the arrangement being such that, during the rotational movement of the transfer cylinder, each of the plurality of transfer surface sections receives the image portion transferred from the associated stamping roll after which each of the retractable sections temporarily retracts radially inwardly within the transfer cylinder each time it opposes a different one of the stamping rolls except for that transferring the image portion to the same, and then all the transfer surface sections bearing the image portions respectively oppose the rotating containerto print the image portions on the outer surface of the container.

Preferably, the transfer surface section of said plurality of sections last receiving an image portion from an associated roll is non-retractable.

The invention will now be more particularly described with reference to the accompanying drawings, wherein: Figure 1 is a side elevational view of one embodiment of a combined multicolour rotary photogravure and offset press constructed in accordance with the present invention with parts illustrated in section; Figure 2 is a plan view of the essential portion of the arrangement shown in Figure 1 as viewed from the bottom; and Figure 3 is schematic diagram illustrating various patterns in which the transfer image may be divided into portions by the present invention.

In one embodiment of the present invention shown in Figure 1, a circular container is adapted to be printed in two different colours on two portions circumferentially adjacent to each other of its outer surface. The arrangement illustrated comprises a circular container 10 shown as a circular bottle rotatably sandwiched between a rotary transfer cylinder 12 and a rotary impression cylinder 16. The bottle 10 is formed of plastics material. The transfer cylinder 12 includes a circular transfer surface layer divided into a plurality of transfer surface sections.In this case, a transfer layer 18 is formed of a silicone rubber and includes six depressible transfer surface sections 20a, 20b, 20c 20d, 20e and 20f disposed at equal angular intervals of 60 degrees and alternately located stationary transfer surface sections 22a, 22b 22c, 22d, 22e and 22f which are longer in arc length than the depressible surface sections.

Each of the depressible transfer surface sections, for example, the surface section 20a is operatively coupled to a bearing 26a located thereunder and journalled a pin 24a pendenttherefrom. The bearing 26a is arranged to slide along an inner peripheral surface of a stationary cam guide 28 disposed below the transfer cylinder 12 with the rotation of the transfer cylinder 12. The cam guide 28 includes a peripheral surface coaxial with the transfer cylinder 12 and smaller in diameter than the latter except for that portion thereof opposing a stamping roll 38 as will be described later. The last-mentioned portion of the cam guide 28 is radially inwardly recessed.Also the bearing 26a is operatively associated with a compression spring 30 shown as by the surface section 20a in Figure 2 and fixedly secured at the radially inner end to a fitting 32 subsequently connected to a rotary shaft 34 of the transfer cylinder 12.

Therefore each of the depressible transfer surface sections 20a to 20f inclusive is supported by a supporting mechanism formed of the components 24 to 32 inclusive as above described so as to be normally flush with the adjacent stationary transfer surface sections by means of the action of the associated compression spring 30. When each of the bearings 26 siides along the inner peripheral surface of the cam guide 28 having a shape as above described to reach the recessed portion thereof opposed to the stamping roll 38 during the rotation of the transfer cylinder 12, the same is radially inwardly moved to cause the associated depressible transfer surface section to retract radially inwardly within the transfer cylinder 12 as shown by the surface section 20a in Figure 2.That is, the mating bearing 26 is moved toward the rotational shaft 34 by a predetermined minute distance and against the action of the associated compression spring 30 thereby to depress the mating transfer surface section as determined by the movement of the bearing. After the bearing has been moved past the recessed guide portion, the associated surface section 20a is returned to is original position. The arrangement further comprises a pair of stamping photogravure rolls 36 and 38 disposed The drawings originally filed were informal and the print here reproduced is taken from a later filed formal copy.

in rotational engagement with thetransfersurface layer 18 of the transfer cylinder 12 and angularly spaced from each other.

Accordingly, the arrangement is basically similar in operation to combined rotary photogravure and offset presses of the well known type excepting that, in orderto effectthe simultaneoustwo-colourprint- ing, a pair of stamping photogravure rolls are operatively coupled to the transfer cylinder one for each colour and the transfer surface is partly depressible.

In operation ,the photogravure rolls 36 and 38 are fed with two types of gravure ink different in colour from each other to form predetermined image portions on the surfaces thereof respectively. The image portions as having been transferred to the bottle 10 form the desired image coloured as desired.

As shown at the arrows in Figure 2, the transfer cylinder 12 is rotated in the counterclockwise direction as viewed from the bottom thereof and the bottle 10, and the stamping rolls 36 and 38 are rotated in the clockwise direction while engaging the transfer cylinder 12.

Under these circumstances when each of the depressible transfer surface sections, for example, the surface section 20a comes under the stamping roll 36, it remains its normal position to engage the image bearing portion of the latter. As a result, the image portion is transferred to the depressible transfer surface section engaging the roll.

During a further rotation of the transfer cylinder 12, the transfer surface section 20a bearing the image portion 40 as shown at dots in Figure 2 comes under the stamping roll 38 whereupon it istemporar- ily depressed to its position illustrated as by the surface section 20a in Figure 2. Therefore the stamping roll 38 is prevented from damaging or peeling the image portion on the depressible transfer surface section 20a in Figure 2. Therefore the stamping roll 38 is prevented from damaging or peeling the image portion on the depressible transfer surface section.

When the image bearing surface section ieaves the stamping roll 38, the same is immediately returned to its normal position while the next succeeding stationary transfer surface section such as the surface section 22f engages the stamping roll 38.

As that portion of the roll 38 engaging the stationary surface section bears the image portion, as shown at solid arc in the roll 38 in Figure 2, that image portion is transferred to that portion of the stationary surface section engaging the roll 38.

In the arrangement, of Figure 2, each of the stationary transfer surface section last receives the image portion from the stamping roll 38.

The transfer cylinder 12 is further rotated until the depressible and stationary surface section bearing the image portions 42 and 44 respectively come suc cessively under the rotating bottle 10 as shown by the surface sections 20b and 22a in Figure 2. At that time, as the depressible surface section is not depre ssed, the image portions 42 and 44 transferred from the stamping rolls 36 and 38 successively transferred to the outer surface of the rotating bottle. That is, those image portions are printed on the outer sur face of the bottle 10.

Then the printed bottle 10 is carried out by any suitable conveyor (not shown) and the next bottle (not shown) is rotatably sandwiched between the transfer and impression cylinders 12 and 6. The new bottle is printed by repeating the process as above described.

The image portions 42 and 44 born on the transfer surface sections 20b and 22a respectively have been transferred from the stamping rolls 36 and 38 respectively in the just preceding transfer cycle.

From the foregoing it is to be understood that, only when each of the depressible transfer surface sections 20a to 20f inclusive reaches its position where it is opposed to the stamping roll 38, the same is depressed as above described.

The present invention has been illustrated and described in conjunction with the divided two colour printing that is the simplest and the resulting printing is shown by a pattern A in Figure 3.

Figure 3 shows various divided patterns which can be printed on circular containers by the present invention. In figure 3, areas labelled the reference characters X, Y and Z designate printed letters and/or figures having different colours. For example, pattern C is printed in three different colours, and requires three stamping rolls.

In each of patterns A to I shown in Figure 3, one can determine at will the manner in which the areas X, Y and Z are selectively alloted to the depressible transfer surface sections 20a, 20b, 20c, 20d, 20e and 20f.

It will readily be understood by those skilled in the art that a pattern in which the transfer surface of the transfer cylinder is divided into a plurality of transfer surface sections and the number of and configuration areas applied to stamping rolls can be selected to be suited to any of printed patterns such as shown in Figure 3. In this case, that transfer surface section receiving last from an associated stamping roll is not required to be depressible and therefore the number of the depressible transfer surface sections is sufficient to be less than the number of colours required for a printed image by one. If desired, all the transfer surface sections may be depressible.

Thus it is seen that the present invention can efficiently provide a wide variety of simultaneous divided multicolour printings which are excellent in both design and accuracy and possess high quality.

The present invention is equally applicable to any desired pairs of depressible and stationary transfer surface sections for two-colour printings. In the latter case, the number of surface sections may be selected in accordance with a diameter of a transfer cylinder, a dimension of a printed area, a printing speed etc., as in conventional transfer cylinders for printing circular containers. Also hydraulic cylinder means may be used to depress the depressible transfer surface section.

Claims (5)

1. A combined multicolour rotary photogravure and offset image press for printing an image includes ing divided portions in multicolour on an outer surface of a container having a circular cross-section comprising a rotary transfer cylinder having a transfer surface which includes a plurality of transfer surface sections one for each of different colour imparted to divided image portions respectively, means for disposing the container to be printed in rotational engagement with the transfer surface of the transfer cylinder, a plurality of stamping photogravure rolls disposed in rotational engagement with the transfer surface of the transfer cylinder and having respective image portions formed thereon to correspond to the divided image portions respectively, the stamping rolls being assigned to the transfer surface sections respectively so that each of the stamping rolls transfers the image portion formed thereon to the assigned transfer surface section when opposed to the same during the rotational movement of the transfer cylinder, and support means for supporting at least all but one of said plurality of transfer surface sections for retraction radially inwardly within the transfer cylinder, the arrangement being such that, during the rotational movement of the transfer cylinder, each of the plural ity of transfer surface sections receives the image portion transferred from the associated stamping roll after which each of the retractable sections temporarily retracts radially inwardly within the transfer cylinder each time it opposes a different one of the stamping rolls except for that transferring the image portions to the same, and then all the transfer surface sections bearing the image portions respectively oppose the rotating container to print the image portions on the outer surface of the container.

2. A combined multicolour rotary photogravure and offset press according to claim 1 wherein the transfer surface sections capable of bearing the image portions are arranged that in use they successively oppose the rotating container to print successively the image portions on the outer surface of the container one after another.

3. A combined multicolour rotary photogravure and offset press according to claim 1 or claim 2 wherein the transfer surface section of said plurality of sections last receiving an image portion from an associated roll is non-retractable.

4. A combined multicolour rotary photogravure and offset press according to claim 3, wherein, in orderto print atwo-colourimage on the container, the transfer surface of the transfer cylinder includes six retractable transfer surface sections disposed at equal angular intervals and alternately located stationary transfer sections and a pair of stamping photogravure rolls operatively coupled to the transfer cylinder.

5. A combined multicolour rotary photogravure and offset press, substantially as herein described with reference to Figures 1 and 2 of the accompanying drawings.