CA1101729A - Carriage for web treating machines such as printing machines or the like - Google Patents

Abstract

ABSTRACT

A carriage supporting a printing or applicator cylinder for use in a machine for the continuous treatment of web is provided with a supplementary doctor blade immediately after the region of contact with the web to clean from the roll any material which may have been transferred onto it from the web, such material having been applied to the web in a preceding stage in the treatment process, thereby avoiding the necessity to dry the web between successive contacts with cylinders; deflector rolls for the web are similarly provided with supplementary doctor blades; all the doctor blades are provided with collection channels for disposing of the material cleaned from the cylinders or rolls.

Description

~he l)resent in~ention relates to a mach.ine for the treatment of an elon~ate ~eb, that is material in elon~ate larninar strip forrn, such as paper, ~abric, pl~stics or the like. r~;achines to which the riresent invention relates inclu.de machines for rotogravure printing, painting rnachines, spreading machines and the li1ce. Such machines, rather than being mo1mted on a single base, are often composed of a plurality of sets of cylinders or rolls mounted on inc1ividual carriages in separate units from one to the other of which the web passes as it is ~rocessed.
~he present invention relates in particular to carriages used in such types of machine for supporting the operating cylinders or rolls, that is 'co say the cylin~ers or rolls which during operation of the machine transfer printing ink or other substance (waxes, paints, hot melt, or other) to the web.
In conventional machines for multi-colour roto~raw re printing, current printing technology requires the use of an adequate drying stage after the printing of each colour in order to avoid the possibility that the web, still wet with lnk of this colour, might transfer such ink to the rolls over !~hich it passes, since in doing so it wculd modify the colour tones subseauent to the first by contaminating subsequent colours. ~his arises when printing cylinders subsequent to the il~st become sailed with traces of the -4~P
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-colour previously deposited on the web, and transfer these traces of colour to the in~ basins from which ink is transferred to the cylinders, where they mix with the ink in them, altering the chromatic characteristics of this ink.
The present invention seeks to provide apparatus in which it is possible to economise on the cost of drying the inks applied to the web and at the same time to reduce the percentage of rejects from the process, therehy significantly reducing the cost of the final product without reducing the technical possibilities of such a machine, which retains its a~ility to print several superimposed colours, when required, in which case the web passes through a drying station after each colour has been applied.
According to the present invention, there is provided a carriage supporting a treatment cylinder, for use in a machine working on an elongate web to continuously treat same, the carriage including:
a support structure, the treatment cylinder, means supporting the treatment cylinder on the support structure, at least one supplementary doctor blade, means supporting the supplementary doctor blade on the support structure and in contact with the treatment cylinder immediately after the region of contact between the treatment cylindex and the web, whereby to allow the application to the web, while still wet with material applied thereto in a previous treatment stage of the machine, of material by the treatment cylinder in positions which are not superimposed over the material previously applied without the necessity for drying the material previously applied before contact with the treatment cylinder, and a second doctor blade immediately in advance of the region of contact between the cylinder and the web and adapted for metering fluid on the surface of the cylinder, the second, metering, doctor blade being provided with a pair of skids each contacting a corresponding end of the cylinder, for cleaning the ends of the cylinder.

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Various embodiments of the present invention ~ill no~
~e more p2,rticularly descri'~ed ~ith reIerence to the a'Gt2c~ed schematic dra~!in~s, provided bv ~ay of example, ~ith reference to the <-~ccompanying dra~in~,s, in wi~ich:
Figure 1 is a schema-tic side vie~! of ~rinting apparatus incorporating carriages formed as embodiments of the t?resent invention;
Figure 2 is a plan vie~!r of a c~Tlin~.er suitable for use on a carriage sv.ch as that illustrated in Figure 1;
Fi~ure 3 is a perspective vie~! o- one end of the cylinder illustrzted in Figure 2;
Fi~,ule 4 is a front vie-~, on an enlarged ,sca~e, of one mountin~ arrangement at the end of a c~linder5 'Figure 5 and 6 a,re respec~ively an ena vie~t ana a. front view of an alternative rnounting system for a cylinder, permi-ttin~ sim~le and rapid de-mountin~ of the cylinder from its supports;
Fi~re 7 is an axial section of a cylinder mounted in a carriage ~ith a different movnting system;
Fi~ure a is a plan view of the cylinder and mounting system s~lo~m in Figure 7;
~igure 9 is a cross section of a carric"~e formed as a further embodiment of the invention;
~igu.re 10 is a schematlc end view of a further embodiment of the invention; and `..

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~i~ures 11 to 14 are schematic diagrams illustra-ting various ~ios~ible arrangements of the carriage of the present invention.
Referrinr no~r to the dra~ings, in ~i~u.re 1 there are sho~m t~!o carriages belonginr to t~:~o successive println~
units of printing machine svch as the E~F~X~machine made by "~ecmo", or other sirnilar such machine. T~.e paper ~reb, onto which the first colour has been rinted with a normal rotogravure process, pa~sses over chromium plated aeflector rolls D, which may be driven or freely rotat~ble, ~hich rolls are provided with respective cleaning doctor blades R5, R6 ~rhich remove any ink transferred to tne deflector roll from the still wet ~reb as it passes over the roll so that the roll always rernains clean under the printed paper as it arrives.
Without touching any other rollers the web passes between a pressure cylinder 1 and an impression or printing cylinder 2 which æerves to print the second colour ~!hich, in general, is not superimposed on the first. During ZO printing of thls second colour the impression cylinder 2, hich prints this second colour, becomes soiled with the first colour ~rhich is not yet dried, but a doctor blade R3 positioned on the engraved impression cylinder 2 immediately after the printing region, cleans all the surplus in~ from it, including the ink of the first colour deposited on it, ~ 7--~o~G,~ ~

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so that the impression cylinder 2 is ready again for immediate immersion in the colour it is to print and the printing can continue without undergoing variations in hue.
~rhe third and successive colours are printed in the same way as the second. After the last colour the web passes into a drying tunnel (not sho~m) from ~here it passes to a winding-up machine.
If it is required to print seve-~al superimposed colours, it is sti1l necessary, before superimposing a subsequent colour for the web to be passed through a drying tunnel associated with the printing section concernea, the ~^!eb thus dried then being printed with the superimposed colour.
~y using a conventional printing machine, with the roll units supported by a carriage 3 as described above~ having a number of doctor blades, one of which,the doctor, R3, is for cleaning the impression cylinder 2 it is possible to print several non-superimposed colours whilst requiring only one drying stage: this achieves a very notable savin~ of energy and of web material, since the web path is very much - - shorter by avoiding the drying tunnel, apart from the single pass therethrough as the final stage.
Moreover, if it is desired to deflect the web to give greater accessibility to the operator in the ~rinting zone, a number ~f deflector rolls D may be used, provided that , ; - 6 -, . .

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one or more doctor blades R5, R6 are fitted to the deflector roll or rolls D to clean off any ink transferred thereto from the still wet we6s passing over it or the~. Although it is possible to reduce the drying sta~es to a single pass through the dryin~ tunnel when printing several non-superimposed colours, never~heless, it is unavoidable that, when printing one or more superimposed colours with conventional systems, the first colour must be dried before printing the next.
~he carria~e 3 may be ~rovided, as shown in Figures 2, 3 and 4, with an ink tank doctor blade R1, which avoids the necessity for a lar~e amo~nt of ink. In such an embooiment, ~ the impression cylinder is -~rovided with two skids 4 for ; each doctor blade, the skids acting on respective end surfaces of the roll. ~ach skid 4 (which may be made, for f e f ~o~
example, of~fl~n or nylon) is carried by a flexible support and is ur~ed under pressure against the roll 2. r~oreover, each skid 4 may be provided with blocks 5 of soft material each serving as a dam for retaining the ink in the space define~ between the doctor blade R1 and the cylinder, as illustrated in Figures 2 and 3~ providin~ the doctor blade R1 with such lateral walls the carriage can print with only a few grammes of ink; printing with ink circulation can be effected by removing the lateral walls and allowing the in~ to flow down the ends of the cylinder.

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L72~3 Because oi the provision o f the lateral skids 4 the cylinder 2 has no in~ residue on its non~engraved surfaces after ha~ing passed the doctor bla~e R1, that is on its edges and its ends, and so the cylinder can be driven at h-gh velocities without the centrifugal force creating spray before printing.
If, 1nstead o.- distributing relatively hin ink ~luids, it is intended to use a thick paint, wax, hot melt or other such thic~ fluid, another doctor blade R2 (Figure 1) is provided imrnediately after a small tray 6 into which the roll

2 dips. ~he roll is then i~.~ediately scraped after having collected the fluid from the tray 6 so that the surface of the roll is cleaned in a very uniform manner, and without a large overflow movement of the liauid. A cleaning doctor R3 which engages the roll 2 iminediately after its contact :~ with the web, cleans the surface of the roll of any . impurities.
~ en using only the two doctors R1 and R3 it is possible to mount the cylinder 2 on the carriage 3 using a mounting system such as that sho~m in Fi~ures 5 and 6, :~ which, permits rapid mountinE or de-mounting of a cylinder2 of the type having axial end spi~ots 2a, to or from the carriage 3. As is illustrated in Figures 5 and 6 the carriage 3 is provided with upright supports at the ends which have shaped recesses to receive the ena spigots 2a :

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of the cylinder 2. Pressure screws ~ are provided for locking the spigots to the recesses once they have been inse~ted therein. ~he cylinder 2 can thus be withdra~m from the carriage 3 quickly and easily, simply by slackening the ~q, two screws ~, without even having to remove the carriage 3 from its position in the machine.
Figures 7 and 8 illustrate an alternative embodiment in which the cylinder is not provided with external spip~ots but is hollow with open ends. In this case the cylinder 2 is supported on the two lateral upright supports of the carriage 3 by means of two cones 7, 8 one (7) of which is driven by drive means (not shown) whereby to effect rol.ational movement to the cylinder 2 about its longitu(3inal axis, and the other of which is freely rotatable and axially slideable. ~y retracting the said other cone 8 the cylinder 2 is released to be lowered down onto two supporting brackets 9 which are linea with xesilient material. In this embodiment also, therefore, the cylinder 2 can be removed without displacing the carriage 3 from its normal operating position. Two end stops 10 projecting up from the brackets 9 help to position the roll 3 when it is being fitted to carriage 3.
~igure 9 illustrates another embodiment in which, in place of the separate tank 6 a part 11 of the carriage 3, which spans between the uprig~ht supports, is shaped to serve _ g _ . _.

7 2g as the tank. As ~an be seen in Figure 9 the carriage 3 is provided with one or more discharge tubes 12, secured by a ~uick release couplin~ to a tube 13 attached to the part 11 of the carriage 3 to serve as an overflow to maintain the 5 level of liauid in the tank 11. The height of the tube 13 can thus be readily adjusted to control the level of liquid in the tank 11 to maintain the required height in depenaence on the aiameter of the cy]inder 2 dipping into it. The discharge tube or tubes 12 is or are each provided with a 10 filter 14 and with a helical ~ide 15 which permits the ink or other liquid to slide do~n smoothly from the upper tank 11 to a lo~er container 16 without agitation, and therefore without the formation of froth. ~he lo~er container 16 is provided with inclined sides for facilitating the introduction - 15 of a disposable lining of plastics material which can be disposed of when the colour is changed to avoid the necessity for extended cleanin~ operations. Alternatively ~emovable metal trays having a complementary form may be used; the i inclined sides of the disposable linings or of the removable -~ 20 trays make them easily stackable for storage.
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he structvre of the carriage 3 is also provided with lateral flanges 17 wThich can be engaged by the fork of a . .
forklift truck ~Then large changes of position of the carriage

3 are re~v,ired. For smaller adjustments to its position the carriage 3 is provided with castors 18.

'' _ 10 -Two shaped covers 19, hin~ed to the carriage 3, permit the partial enclosure of the impression cylinder 2 sufficient to maintain around it an environ~ent of saturated air, thereby avoiding rapid drying of -the ink in the engraved recesses.
The doctor blades illustrated in Figure 1 may be displaced towards or away from the cylinder 2 by means of a double acting fluid pressure actuator inserted in an hydraulic or pneu~atic circuit having a device for reversing the flow of fluid, when required to change the direction of zction of the actuators. Obviously it would be possible to use other systems, either mechanical~ electrical or of other type. In fact, a mechanical system is preferred, s-uch as the counterweight arrangement illustrated in Figure 1, in ~hich there are illustrated lever arms having counterweights 20. As can be seen in ~igure 1 the levers and counterweights may lie between the fulcrum and the cylinder 2 or may lie on the side of the fulcrum remote from the cylinder. The use of counter-weights avoids the necessity for connectin~ pipes, wires or other mechanical parts for creating the reguired force for applying the doctor blades, such as would be required with electrical, hydraulic or pneu~atic systems, and has the advantage that the reauired constant pressure can be applied with minimum inconvenience.
In Fi~vres 10 to 14 there are sho~n several different possible ~ays of using carriagesaccording to the present invention. In each of Figures 10 to 14, the reference numeral ~3 indicates a doctor blade serving for cleaning the irnpression cylinder after printing and this ~octor is provided with a collection channel 21 for collecting the material removed, and channelling it into a suitable discharge duct. In ~igure 10 a further doctor R4, ~rhich is provided wi.th a pair of lateral skids 4, serves for spreading and levelling the ink collected by the roll 2 upon its imrnersion in the tan~ 6: sv.ch a system is only suitable, however, when using ink of low density.
In the system shown in Figure 11, the doctor R1 functions as an ink spreader and metering blade and has a pair of end skids 4 which may or may not be provided with end walls 5 of the type discussed in relation to the embodiment of Figures 2 and 3.
In the embodiment of ~igure 12, the doctor blade R1 functions as an ink applicator and has end skids 4 but no end walls. ~he doctor blade R4, which also has end skids 4, 2~ functions as a spreading and levellin~ device for the ink distributed by R1: again this system is only suitable for ; ink of low density.
In the systems shown in ~igure 13 the doctor blade R1 functions as an ink applicator as in Figure 12. ~his system is adapted for applying ink of high density to the cylinder 2 _ 12 -.
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and the meter1ng of the ink is effected by means of a doctor blade R2 having skids 4.
~he embodiment illustrated in Figure 14 is similar to the embodiment of Figure 10 but instead of the doctor R4 it has a doctor R2, with a pair of skids 4, which serves as a metering device for ink of high density.

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Claims (24)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A carriage supporting a treatment cylinder, for use in a machine working on an elongate web to continuously treat same, said carriage including:
a support structure, said treatment cylinder, means supporting said treatment cylinder on said support structure, at least one supplementary doctor blade, means supporting said supplementary doctor blade on said support structure and in contact with said treatment cylinder immediately after the region of contact between said treatment cylinder and said web, whereby to allow the application to said web, while still wet with material applied thereto in a previous treatment stage of said machine, of material by said treatment cylinder in positions which are not superimposed over said material previously applied without the necessity for drying said material previously applied before contact with said treatment cylinder and a second doctor blade immediately in advance of said region of contact between said cylinder and said web and adapted for metering fluid on the surface of said cylinder, said second, metering doctor blade being provided with a pair of skids each contact-ing a corresponding end of said cylinder, for cleaning said ends of said cylinder.

2. A carriage as in Claim 1, wherein there are further provided:
shaped covers, means hingedly connecting said shaped covers to said support structure, said shaped covers, when closed, at least partially enclosing said treatment cylinder whereby to reduce evaporation from the surface of said treatment cylinder and to serve as safety covers.

3. A carriage as in Claim 1, wherein said supplementary doctor blade acting on said treatment cylinder immediately after said region of contact between said treatment cylinder and said web is provided with a collection channel for the discharge of material removed from said cylinder.

4. A carriage as in Claim 1, wherein there is provided a third doctor blade adapted to operate as a fluid applicator.

5. A carriage as in Claim 4, wherein said third, fluid applicator, doctor blade is provided with a pair of skids acting one on each of the ends of said cylinder.

6. A carriage as in Claim 1 or Claim 5, wherein said skids are provided with lateral containing elements serving as dams for retaining fluid to be applied to said cylinder.

7. A carriage as in Claim 5, wherein there is provided a fourth doctor blade adapted as a metering device for the fluid applied to said cylinder.

8. A carriage as in Claim 7, wherein said fourth, metering, doctor blade has a pair of lateral skids each acting on one of the ends of said cylinder.

9. A carriage as claimed in Claim 1, wherein said support structure carries a tank containing liquid to be applied to said cylinder, said cylinder dipping into liquid contained in said tank, said tank being provided with at least one discharge duct, a filter in said discharge duct for retaining impurities in the liquid which can then be recirculated.

10. A carriage as in Claim 9, wherein said at least one discharge duct acts as an overflow and includes:
a fixed part, and a movable part, said movable part being connectable to said fixed part by quick release couplings permitting ready adjustment of the height of said liquid in said tank in dependence on the diameter of said cylinder and the depth it is to be immersed in said liquid in said tank.

11. A carriage as in Claim 9 or Claim 10, wherein the lower part of each discharge duct contains helical guide means, said helical guide means assisting in avoiding the formation of foam in the liquid which passes down it through said discharge duct.

12. A carriage as in claim 1 wherein there is provided a reservoir for liquid to be applied to said cylinder, said reservoir comprising a container having inclined sides for facilitating the introduction of one of:
a disposable lining of plastics material, and a removable metal tray having walls of the same inclination as said container, the inclination of said walls facilitating stacking in a store.

13. A carriage as in claim 1, wherein said support structure is provided with projecting flanges for engage-t by the fork of a forklift truck.

14. A carriage as in claim 1, wherein said support structure is provided with castors for permitting small positional adjustments to said carriage.

15. A carriage as in claim 1, wherein each said doctor blade is provided with quick release means for permitting a rapid displacement from said treatment cylinder whereby to facilitate cleaning or removal of said treatment cylinder.

16. A carriage as in claim 1, wherein there are provided fluid pressure actuators urging each said doctor blade into contact with said treatment cylinder.

17. A carriage as in claim 16 wherein there are provided double acting fluid pressure actuators in a fluid pressure circuit provided with means for periodically reversing the flow of working fluid whereby to control the pressure with which each said doctor blade is urged into contact with said treatment cylinder.

18. A carriage as in claim 1 wherein there are pro-vided electrical means urging each said doctor blade to-wards said treatment cylinder.

19. A carriage as in claim 1 wherein there is provided a mechanical counterweight and lever system urging each said doctor blade into contact with said treatment cylinder.

20. A carriage as in claim 1, wherein said treat-ment cylinder is mounted on said support structure of said carriage by quick release couplings.

21. A carriage as in claim 20, wherein said treat-ment cylinder has end spigots, and said support structure of said carriage is provided with means defining shaped recesses for receiving said end spigots of said treatment cylinder, and pressure screws on said support structure for locking said end spigots in position in said recesses in said support structure.

22. A carriage as in claim 20, wherein said treat-ment cylinder comprises a hollow sleeve without end spigots, and said support structure of said carriage includes:
two cones, means. supporting said two cones coaxially to penetrate one into each end of said treatment cylinder, means for driving a first said cone to rotate about an axis coincident with the axis of said treatment cylinder, means for effecting displacement of the second of said two cones axially to said treatment cylinder where-by to facilitate removal of said treatment cylinder, and supporting brackets located beneath said cones whereby to support said treatment cylinder when said second of said cones is displaced axially to permit said treatment cylinder to be removed therefrom.

23. A carriage as in claim 22, wherein said support-ing brackets are provided with:
resilient linings and abutment stops whereby to facilitate locating said treatment cylinder when it is being assembled to said carriage.

24. A machine incorporating a plurality of carriages as claimed in claim 1 wherein there are provided deflector means for deflecting said web over one or more deflector rolls, each said deflector roll having a cleaning doctor for removing material transferred thereto by said web upon passing over said deflector roll while still wet, said deflector rolls allowing greater accessibility at the region of contact between said web and said treatment cylinder.