WO1999037483A1

WO1999037483A1 - Hot foil printing machine

Info

Publication number: WO1999037483A1
Application number: PCT/GB1999/000039
Authority: WO
Inventors: Steven Smith
Original assignee: Artfoil Graphic Machinery Limited
Priority date: 1998-01-21
Filing date: 1999-01-19
Publication date: 1999-07-29
Also published as: GB9801136D0; CA2284535A1

Abstract

A hot foil stamping press (10) comprises a bed (12) which is mounted to move in a reciprocating motion beneath a printing cylinder (14). Foil (16), which is laminated onto a polyester backing (20), is supplied from feed rolls (18) housed in a supply section (22). Foil (16), is pulled from the roll (18) when the bed (12) has moved to a position beneath the printing cylinder (14), after a printing operation has been carried out. The remaining polyester backing (20) returns to the supply section (22) after passing through an opening (24) in a lower section of the bed (12).

Description

- 1 - HOT FOIL PRINTING MACHINE

This invention relates to a printing machine, particularly, but not limited to, a hot foil stamping press and to a method of supplying foil to a hot foil stamping press .

An existing hot foil stamping press comprises a printing bed which holds a die and a printing cylinder, on which sheets to be printed are retained. A roll of foil laminated onto a polyester backing is housed beneath the printing cylinder and supplied to the dies on the printing bed which transfer foil onto the sheet being printed. The printing bed is movable in a reciprocating motion between a first position in which the printing bed and dies pass beneath the printing cylinder for the printing operation and a second position in which the printing bed and dies return underneath the printing cylinder. During movement to the second position causes transfer material to be drawn from the roll of foil and polyester. As the printing bed is moving to and fro, the printing cylinder rotates to feed sheets for printing between the cylinder and the die and to remove printed sheets.

Serious disadvantages arise with this arrangement because the size of a roll of foil which can be used is limited by the space between the printing cylinder and the structure of the base. Typically a machine can only run for approximately half an hour until the roll must be replaced. Inefficiencies and excessive running costs arise from the arrangement described above.

It is an object of the present invention to address the above mentioned disadvantages. According to a first aspect of the present invention a printing press comprises a supply section for a web of transfer material, a printing cylinder and a printing bed, and a return store for the web of transfer material, the arrangement being such that in use, with the web of transfer material extending from the supply section, between the printing cylinder and printing bed and back to the return store, the printing cylinder and printing bed can be caused to cooperate to transfer material from the web to an article on the printing cylinder, the supply section and the return store both being located to the same side of the printing cylinder and printing bed.

Preferably the printing bed is movable from a retracted position spaced, preferably laterally spaced, from the printing cylinder to an extended position under the printing cylinder, in which position a length of transfer material may be drawn from the supply section, for some of the transfer material to be transferred.

The press may be such that after the transfer, the printing bed returns to the retracted position.

The printing bed may include at least one die which may be located on an upper surface of the printing bed.

The printing press may be a hot foil stamping press. The web of transfer material may be foil having a suitable backing material, which may be polyester.

The supply section may include a roll of the web of transfer material. The supply section roll may be powered to supply material upon receiving signals from a control means . - 3 -

The supply section roll may be mounted on a frame portion of the supply section. The frame portion may accept a variety of sizes of supply section roll. The supply section roll may have a diameter up to 40cm. The supply section may comprise a length of transfer material up to 5000m.

The printing bed may have an opening therein, which provides a return path for the web of transfer material . The opening may extend through the printing bed. Preferably the opening extends along the length of the bed. The opening may be located in a lower part of the printing bed. The opening may be a channel, which may be enclosed and may extend through the interior of the printing bed. The opening may be strengthened in order to maintain the rigidity of the printing bed. The location and/or size of the opening may be chosen to maintain the rigidity of the printing bed at a value which maintains a chosen separation of a printing cylinder and the printing bed.

The printing bed may have opening strengthening means, which may be movable between operative and inoperative positions. The opening strengthening means may be operable to move from the inoperative position to the operative position when the printing bed is in the retracted position, ready to pass beneath the printing cylinder. Preferably, the opening strengthening means is arranged to be in the operative position during transfer of material from the web to the article on the printing cylinder. The opening strengthening may be operable to move from the operative position to the inoperative position after transfer of material from the web to an article on the printing cylinder. The opening strengthening means may comprise at least one support which, in the operative position, extends between upper and lower boundaries of the opening .

The opening strengthening means may comprise a support extending between upper and lower boundaries of the opening and may have a cutting upper edge, which may be arranged, in use, to cut transfer material entering the opening. The position of the support may be laterally adjustable.

Preferably, the or each support extends along the length of the opening.

The or each support may move between said operative and inoperative positions about a pivot. The, or each support may be an eccentric cam. The or each support may have a pivot pin secured at one end, the other end may be journalled. The support may be moved between operative and inoperative positions by mechanical means, which may be a push-rod, or by electromechanical means, which may be an electric motor. The or each support may be located above rollers of the printing bed, which rollers facilitate movement of the printing bed.

The return store may be located adjacent to the supply section, or may be located in the supply section.

The return store may include a return roll, which may be mounted on the frame of the supply section. The return roll may be controllable so that it may only turn in a direction to wind material on to the roll. The return roll may be powered. The return store may comprise transfer material tension control means, for controlling the tension in the transfer material . The tension control means may comprise first and second rollers.

The first and second rollers may be biased to maintain contact with each other. The web of transfer material may be arranged, in use, to pass between said first and second rollers. The first roller may be a metered roller. The second roller may be a nip roller.

The invention extends to a feed mechanism for a printing press, which feed mechanism comprises a supply section and a return store according to the first aspect.

According to another aspect of the present invention a method of feeding a web of transfer material to a printing press having a supply section for said web of transfer material, a printing cylinder, a printing bed and a return store, comprises feeding said web of transfer material from the supply section between the printing cylinder and the printing bed, and back to the return store, the printing bed and the printing cylinder can be caused to cooperate to transfer material from the web to an article on the printing cylinder, in which the supply section and the return store are both located to the same side of the printing bed and printing cylinder.

The printing press may be a hot foil stamping press.

The method may include the printing bed moving from a retracted position spaced, preferably laterally spaced, from the printing cylinder to an extended position under the printing cylinder, in which position a length of - 6 - transfer material may be drawn from the supply section, for some of the transfer material to be transferred.

The method may include the step of, after the transfer, the printing bed returning to the retracted position.

Any of the above aspects may be combined with any of the features described herein, in any combination.

A specific embodiment of the present invention will now be described by way of example, with reference to the accompanying drawings, in which:

Figure 1 is a diagrammatic sectional side view of a hot foil stamping press in a first configuration;

Figure 2 is a diagrammatic sectional side view of a hot foil stamping press in a second configuration; and

Figure 3 is a diagrammatic sectional view along the line, III-III in Figure 1.

A hot foil stamping press 10 comprises a bed 12 which is mounted to move in a reciprocating motion beneath a printing cylinder 14. Foil 16, which is laminated onto a polyester backing 20, is supplied from feed rolls 18 housed in a supply section 22. Foil 16 is pulled from the roll 18 when the bed 12 has moved to a position beneath the printing cylinder 14 (figure 2) , after a printing operation has been carried out. The remaining polyester backing 20 returns to the supply section 22 after passing through an opening 24 in a lower section of the bed 12. The feed rolls 18 are mounted on a frame 26 of the supply section 22. Return rolls 28 are also mounted on the frame 26 and are powered to wind material thereon.

A nip roller 32 and a metered roller 30 are located beneath the return roll 28. The metered roller 30 is powered and is controlled by a computer (not shown) to turn by a specified amount to thereby pull foil through the press 10. The nip roller 32 is kept in close contact with the metered roller 30 with the foil sandwiched between the two to thereby prevent slippage of the foil 16 on the metered roller 30.

The bed 12 has a die 34 mounted on an upper surface thereof. The reciprocal movement of the bed 12 is arranged so that in a first configuration (see figure 1) the die 34 is laterally separated from the printing cylinder 14, and in a second configuration (see figure 2) the die 34 is beneath the printing cylinder 14.

The bed 12 is mounted on rollers 36, which facilitate the reciprocal motion of the bed 12 mentioned above. The rollers 36 are arranged in four parallel sets 46 which extend along the length of the printing bed 12, between the printing cylinder 14 and the supply section 22.

The opening 24 in the lower section of the bed 12 provides a return path for the remaining foil 16 with its polyester backing 20 from the feed roll 18 to the return roll 28. An upper section 38 has a depth which is sufficiently great to prevent sagging of the bed 12 under its own weight.

The opening 24 is formed by peripheral support bars 42 (see figure 3) which run along the length of the bed 12 - 8 - and hold the upper section 38 above a lower section 44. In order to provide additional rigidity for the bed 12 during a printing operation, two pop-up support beams 48 are provided. The pop-up support beams 48 are located in the opening 24 above the two central sets of rollers 46 and are mounted to be moveable between a first position, in which they lie flat against the lower section 44 to allow the passage of foil 16 through the opening 24, and a second position, in which they are turned to support the upper section 38 of the bed 12 during a printing operation. The pop-up support beams 48 are moved between the first and second positions by means of a push rod (not shown) located at a forward end of the printing bed 12 and is triggered by a computer when the movement of the printing bed 12 is in a preselected position. Each pop-up support beam 48 is mounted on an eccentric pivot 50 to permit movement between the first and second positions. In figure 3, the pop-up support beam 48 on the left is shown in the first position and the pop-up support beam 48 on the right is shown in the second position. In normal use, both pop-up support beams 48 will be in the same position at a particular time.

In use, the feed roll 18 is mounted on the frame 26, the foil 16 and polyester backing 20 is laid over the upper surface of the bed 12, passed through the opening 24 in the bed to return to the return roll 28 via the nip and metered rollers 30 and 32.

To start the printing process the bed 12 is moved from the first to the second configuration (to the right when viewing figure 1) using the rollers 36. When the movement is complete the metered roller 32 is activated to pull material through the bed 12 from the feed roll 18 to - 9 - advance a fresh section of foil 16 over the die 34 for a printing operation.

Excess material is pulled onto the return rolls 28 by the rolls being driven.

At the same time the push rod (not shown) for the two pop-up support beams 48 is activated to move the pop-up support beams 48 from the first position to the second position. Depending on the position of the foil 16 in the opening 24, the pop-up support beams may trap the foil 16 against a lower face of the upper section 38 of the bed 12. This does not affect the functioning of the press 10 because at this stage in the process it is not necessary to move the foil 16.

The printing cylinder 14 then descends slightly to transfer the foil 16 to a sheet 40.

As soon as the foil 16 has been transferred to the sheet, the pop up support beams 48 are caused to return to the first position since the additional support for the upper section 38 of the bed 12 is only required during the foil transfer. The movement of the pop-up support beams 48 to the first position frees any foil 16 which has been trapped against the lower face of the upper section 38.

The bed 12 then returns to the position shown in figure 1.

The movement of the bed 12 between the positions shown in figures 1 and 2 can then be repeated for the next printing operation. Each time a printing operation is performed, the printing cylinder 14 rotates to allow - 10 - sheets 40 for printing to be fed onto the cylinder and removed therefrom after printing.

Figure 4 shows an alternative arrangement of support beam to that shown in Figure 3. In the alternative all the parts of the previous embodiment are the same, except that the pop-up support beams 48 are replaced by one or more static support beams 70, one of which is shown in Figure 4.

The static support beam 70 is sharpened at its upper end 72 where it contacts the base of the upper section 38. A blade (not shown) may be included instead of the sharpened end 72.

The static support beam 70 is static insofaras it does not pop up and down in use like the pop-up support beams 48. The static support beam 70 remains in the same position whilst the press 10 is in use.

Foil 16 is passed beneath the bed, as before, but when foil reaches the static support beam it is cut and split as it passes along the beam 70, so that one section of the foil passes to one side and another section passes to the other side of the static support beam 70. This beam 70 is simpler than the pop-up version 48 because no movement is needed in use.

The static support beam may be laterally adjustable by means of two large screws 74 mounted between the two peripheral support bars 42. Rotation of the screws, on which the beam 70 is fixed causes lateral movement of the beam. - 11 -

The hot foil stamping press described herein has significant advantages over prior art hot foil stamping presses because the roll of foil can be located away from a position beneath the printing cylinder. The different position allows a considerably larger roll of foil to be used which can prolong the uninterrupted printing time of a hot foil stamping press by a factor up to 10. The solution of feeding the foil from one side of the bed across the upper surface of the bed and returning through an opening in a lower portion of the bed allows the above mentioned increase in productivity to be utilised. Also, the surprising effect that the rigidity of the bed is not significantly decreased has been used to great advantage.

The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings) , and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) , may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features. - 12 -

The invention is not restricted to the details of the foregoing embodiment (s) . The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings) , or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

- 13 - CLAIMS

1. A printing press comprises a supply section for a web of transfer material, a printing cylinder and a printing bed, and a return store for the web of transfer material, the arrangement being such that in use, with the web of transfer material extending from the supply section, between the printing cylinder and printing bed and back to the return store, the printing cylinder and printing bed can be caused to co-operate to transfer material from the web to an article on the printing cylinder, the supply section and the return store both being located to the same side of the printing cylinder and printing bed.

2. A printing press as claimed in Claim 1, in which the printing bed in moveable from a retracted position spaced from the printing cylinder to an extended position under the printing cylinder.

3. A printing press as claimed in Claim 2 in which in the extended position under the printing cylinder a length of transfer material is drawn from the supply section for some of the transfer material to be transferred.

4. A printing press as claimed in any one of claims 1 to 3, in which after the transfer, the printing bed returns to the retracted position.

5. A printing press as claimed in any preceding claim, in which the printing bed includes at least one die located on an upper surface of the printing bed.

6. A printing press as claimed in any preceding claim, which is a hot foil stamping press. - 14 -

7. A printing press as claimed in any preceding claim, in which the supply section includes a roll of the web of transfer material .

8. A printing press as claimed in Claim 7, in which the supply section roll is powered to supply material upon receiving signals from a control means.

9. A printing press as claimed in either Claim 7 or Claim 8, in which the supply section roll is mounted on a frame portion of the supply section, which frame portion accepts a variety of sizes of supply section rolls.

10. A printing press as claimed in any preceding claim, in which the printing bed has an opening therein, which provides a return path for the web of transfer material .

11. A printing press as claimed in Claim 10, in which the opening extends through the printing bed.

12. A printing press as claimed in Claim 11, in which the opening extends along the length of the bed.

13. A printing press as claimed in any one of Claims 10 to 12, in which the opening is located in a lower part of the printing bed.

14. A printing press as claimed in any one of Claims 10 to 13, in which the opening is a channel, which is enclosed and extends through the interior of the printing bed.

15. A printing press as claimed in any one of Claims 10 to 14, in which the opening is strengthened in order to maintain the rigidity of the printing bed. - 15 -

16. A printing press as claimed in any one of Claims 10 to 15, in which the location and/or size of the opening is chosen to maintain the ridgidity of the printing bed at a value which maintains a chosen separation of a printing cylinder and the printing bed.

17. A printing press as claimed in any one of Claims 10 to 16, in which the printing bed has opening strengthening means .

18. A printing press as claimed in Claim 17, in which the opening strengthening means are moveable between operative and inoperative positions.

19. A printing press as claimed in Claim 18, in which the opening strengthening means are operable to move from the inoperative to the operative position when the printing bed is in the retracted position, ready to pass beneath the printing cylinder.

20. A printing press as claimed in either Claim 18 or Claim 19, in which the opening strengthening means is arranged to be in the operative position during transfer of material from the web to the article on the printing cylinder.

21. A printing press as claimed in any one of Claims 18 to 20, in which the opening strengthening means are operable to move from the operative position to the inoperative position after transfer of material from the web to an article on the printing cylinder.

22. A printing press as claimed in any one of Claims 18 to 21, in which the opening strengthening means comprise at least one support, which, in the operative position, - 16 - extends between the upper and lower boundaries of the opening .

23. A printing press as claimed in Claim 17, in which the opening strengthening means comprise a support extending between upper and lower boundaries of the opening and having a cutting upper edge, arranged, in use, to cut transfer material entering the opening.

24. A printing press as claimed in claims 23, in which the position of the support is laterally adjustable.

25. A printing press as claimed in any one of Claims 22 to 24, in which the or each support extends along the length of the opening.

26. A printing press as claimed in Claim 22, in which the or each support moves between the operative and inoperative positions about a pivot.

27. A printing press as claimed in Claim 26, in which the or each support is an eccentric cam.

28. A printing press as claimed in any one of Claims 22 to 27, in which the or each support is located above rollers of the printing bed, which rollers facilitate movement of the printing bed.

29. A printing press as claimed in any preceding claim, in which the return store includes a return roll, which is mounted on a frame of the supply section, the return roll being controllable so that it may only turn in a direction to wind material on to the roll. - 17 -

30. A printing press as claimed in Claim 29, in which the return store comprises transfer material tension control means, for controlling the tension in the transfer material .

31. A feed mechanism for a printing press which comprises a supply section and a return store according to any one of Claims 1 to 30.

32. A method of feeding a web of transfer material to a printing press having a supply section for said web of transfer material, a printing cylinder, a printing bed and a return store, comprises feeding said web of transfer material from the supply section between the printing cylinder and the printing bed, and back to the return store, the printing bed and the printing cylinder are caused to co-operate to transfer material from the web to an article on the printing cylinder, in which the supply section and the return store are both located to the same side of the printing bed and printing cylinder.

33. A method as claimed in Claim 32, in which the printing press is a hot foil stamping press.

34. A method as claimed in either Claim 32 or 33, which includes the printing bed moving from a retracted position spaced from the printing cylinder to an extended position under the printing cylinder, in which movement to that position results in a length of transfer material being drawn from the supply section for some of the transfer material to be transferred.

35. A method as claimed in any one of Claims 32 to 34, which includes the step of, after the transfer, the printing bed returning to the retracted position.