GB1563120A

GB1563120A - Web printing machines

Info

Publication number: GB1563120A
Application number: GB5151876A
Authority: GB
Original assignee: Reed International Ltd
Current assignee: Reed International Ltd
Priority date: 1976-12-09
Filing date: 1976-12-09
Publication date: 1980-03-19
Also published as: IT1088424B; DE2754676A1; FR2373395A1; ES464916A1

Description

(54) IMPROVEMENTS RELATING TO WEB PRINTING MACHINES (71) We, REED INTERNATIONAL LTD, of 82 Piccadilly, London W. 1, a Company incorporated under the laws of Great Britain, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to web printing machines of the kind having a central impression cylinder for transporting a web wrapped around the surface of the impression cylinder through a plurality of printing stations located at intervals around the periphery of the impression cylinder, each printing station comprising a printing unit with a printing roller for making rolling contact with the web as it passes to imprint on the web the surface configuration of the print roller by the transfer of pigment or the like or by embossment.

The invention has particular, but not exclusive, application to wallpaper printing machines of the so-called sieveless type, in which the pigment is supplied from a colour roller dipping into a pigment or colour box to the printing roller via an intermediate roller rather than via a so-called sieve in the form of an endless felt belt.

According to the present invention there is provided a printing machine having an impression cylinder, a toothed bull gear mounted to rotate with said impression cylinder and a plurality of printing units, each located at a printing station disposed at intervals around said impression cylinder, each said printing unit comprising a printing roller, means for inking said printing roller, and a drive gear, for engagement with said bull gear, mounted to rotate with said printing roller, and means for moving said printing units away from said impression cylinder, so that said printing rollers, together with their associated drive gears, can be removed through the space between said impression cylinder and said printing units when the latter are in the position displaced from said impression cylinder, wherein the improvement comprises corresponding teeth of each of the drive gears associated with said printing rollers being identically marked at teeth spacings corresponding to the number of teeth of said bull gear between successive printing stations, so that, when any one of said printing units is mounted at a printing station with that marked tooth of its associated drive gear which corresponds with the number of that printing station in engagement with said bull gear, its associated printing roller is in at least coarse registration with the printing roller of any other printing unit which has been mounted at another printing station.

On construction of a wallpaper printing machine in accordance with the invention will now be described by way of example with reference to the accompanying drawings in which: Figure 1 shows a side elevation of the printing machine.

Figure 2 shows a view similar to Figure 1, but partly in section and with one of the subframes drawn back, and a cover panel of the other shown removed.

Figure 3 shows an elevation of the machine looking in the direction of the arrow A of Figure 2.

Figure 4 shows a longitudinal section through one of the print rollers.

Figure 5 shows a section through the gear wheel of the print roller on the line V-V of Figure 4, Figure 6 shows a part section through the gear wheel, and Figure 7 is an enlarged fragmentary longitudinal section of a modification of the print roller of Figure 4.

Referring more particularly to Figures 1 to 3, the web printing machine has a main frame 1. A shaft 2 is rotatably supported in bearings 3 carried by the frame 1. Impression cylinder 4 is keyed to the shaft 2 so that it rotates therewith.

Also keyed to the shaft 2 is a bull gear 5 which is driven by electric motor 6 to rotate the impression cylinder. The drive from the motor 6 is by sprocket and chain 7 to intermediate shaft 8, and by gear wheel 9 from the shaft 8 to the bull gear 5. As best seen in Figure 2 the wallpaper web 11 is fed from its supply reel (not shown) to the impression cylinder through tension roller set 12, and guide roller 13. It then wraps around the impression cylinder 4 and leaves the impression cylinder 4 via edge trimmer 15 driven by gear 14. The trimmed off edges are removed through duct member 16.

Extending away from both sides of the main frame 1 are elevated guide track assemblies 17 and 18 which are supported at one end by the main frame 1 and at their other end by posts 19. The assemblies 17 and 18 support sub-frames 21 and 22 respectively so that these sub-frames can be moved laterally relative to the main frame between an operative position indicated by the position of the sub-frame 22 in Figure 2 and a withdrawn position as indicated by the position of the sub-frame 21 in Figure 2. The sub-frames 21 and 22 are hung on tracks 23 forming part of the assemblies 17 and 18 through rollers 24 mounted on cross-shafts 25 (Figure 3). To effect movement along the tracks 23 of the sub-frames, a handwheel 26 is mounted on each sub-frame (only the handwheel associated with sub-frame 22 has been shown) and drives one of the associated cross-shafts 25 through a chain and sprocket drive 27. The subframes 21 and 22 are located in their operative positions by cup and cone registers 28 (Figure 1) and are locked in these positions by hook-type latches 129, which for a final controlled inward movement to their locked positions are actuated by a pneumatic cylinder 29 as will be described.

Each of the sub-frames 21 and 22 carries four printing units. In Figure 2 one of the side plates 30 of the sub-frames 21 and 22 has been omitted to show the printing units 31 to 34 carried by the sub-frame 22; only one of the printing units carried by sub-frame 21 and referenced 35 is partially visible in Figure 2. Thus with both sub-frames 21 and 22 in their operative position, the printing units are spaced around the periphery of the impression cylinder 4 to provide an eight station printing machine.

In Figure 2 the printing stations have been referenced I to VIII. As will be appreciated the number of printing units carried by the subframes can be varied to provide for example a twelve station machine.

Each of the printing units comprises a colour box 36 for containing pigment, a colour roller 37 dipping into the colour box for picking up the pigment, an intermediate roller 38 to which the colour roller 37 transfers the pigment and a print roller 39 which contacts the intermediate roller 38 to pick up pigment therefrom.

In conventional manner as the web 11 is transported through the machine by the impression cylinder 4, the print rollers 39 are in rolling con tact with it and so imprint upon it by pigment transfer the surface configuration or patterns of the print rollers 39. To adjust the contact pressure between each print roller 39 and the impression cylinder manual adjustment screw 41 is provided which operates on a spring loaded slide arrangement one side of which is shown at 81 (Figure 4) to move the print roller assembly including its bearings bodily within the printing unit relatively to the impression cylinder 4.Adjustment screws 42 and 43 enable adjustment within the printing unit of the intermediate roller relatively to the print roller 39 and the colour roller 37 respectively, movement of these latter rollers being effected through slide arrangements similar to that referenced 81.

Referring now more particularly to Figure 4, the frame of a printing unit is indicated at 44 and parts of the roller supporting end of the slid arrangement associated with adjuster screw 41 are shown at 45 and 46. The print roller spindle 47 is rotatably supported in bearings carried by parts 45 and 46. Wedged on to the spindle 47 is a print roller pattern cylinder 49.

Referring now to Figures 4 to 6, each roller spindle 47 also carries a gear wheel 51 for meshing with the bull gear S so that the print roller is driven in synchronism with the impression cylinder 4. To enable the sequential printing of the web at the successive printing stations so that the desired multi-coloured pattern is provided on the web, it is necessary to provide a registration system effectively between each printing roller and the impression cylinder. The first part of this registration system is to align registration pin 52 (Figure 4) on each pattem cylinder 49 with a marked tooth, i.e. tooth 1 (Figure 5) of its associated gear wheel 51. This is done approximately during assembly of cylinder 49 on its spindle and then by a fine adjustment as will be described. The rollers 39 are then oriented relatively to each other so that corresponding pattem areas of successive print rollers come into contacts with the same parts of the web.

This relative orientation is of course related to the angular spacing of the printing stations about the axis of the impression cylinder 4.

To achieve this registration each gear wheel 51 is identically marked with the registration numbers "1" to "8" at predetermined teeth as indicated in Figure 5. The gear wheels 51 are respectively brought into mesh with the bull gear 5 through the tooth "1" at printing station I, through tooth "2" at printing station II and so on up to tooth "8" at printing station VIII.

The position of the numbers "1" to "8" on the gear wheels are determined by the num ber of gear teeth on the bull gear 5 by which successive printing stations are spaced from each other. Thus, for example with a 292 tooth bull gear of 1S " pitch and a spacing between stations I to IV and V to VIII of 20 teeth, and between stations IV and V of 73 teeth, the numbers " 1"-"2", "2"-"3", "3"-"4', , "6'-"7", "7"-"8" will be 20 teeth apart and the numbers "4" to "5" will be 73 teeth apart.

This can be achieved by a 36 tooth gear wheel marked as shown in Figure 5; as shown in Figure 5 the gear wheel 51 will rotate in an anticlockwise direction.

To enable accurate final register of the print rollers to be made with the machine stationary or running, an adjusting arrangement is provided which enables relative rotation between the spindle 47 (and hence the pattern cylinder 49) and the gear wheel 51. Embodied in this arrangement is also an arrangement for "transverse" alignment of the print roller 39 with the impression cylinder 4, this is to say a limited axial adjustment of the print roller 39 in the parts 45 and 46 of the slide arrangement.

Both these adjusting arrangements will now be described.

The print roller spindle 47 is rotatably supported in bearings 53 and 54 which are restrained against axial movement relatively to the spindle 47. However the left hand bearing 53 can slide in its housing 55 and the right hand bearing 54 is located in a sleeve 56, which in turn is axially slidable and rotatable in a housing 57, the housing 57 and sleeve 56 threadedly engaging each other at 58 to provide a lead screw arrangement. The sleeve 56 extends from the housing 57 through the frame 44 of the printing unit and is formed at its end with a hand wheel 59 having a hole 61 for receiving a tommy bar.

Rotation of the hand wheel 59 will cause axial movement of the bearing 54 and hence of the spindle 47, bearing 53 and all parts carried by the spindle 47. Thus "transverse" alignment of the print roller 39 can be effected. After adjustment the sleeve 56 is prevented from rotating by a nylon friction pad held in firm contact with the sleeve by means of a compression spring acted upon by a grub screw 62.

Extending within the sleeve 56 is a spindle 63 which is supported at one end in a bearing 64 mounted in a second sleeve 65. The sleeve 65 threadedly engages the sleeve 56 to provide a second lead screw arrangement. The outer end of the sleeve 65 is provided with a hole 66 for a tommy bar. Thus rotation of the sleeve 65 will cause axial movement of the spindle 63.

At its other end the spindle 63 is supported in a universal joint 67 which is slidably mounted in the print roller spindle 47. The spindle 63 is pinned to the joint 67 by a spring pin 68. Spaced along the spindle 63 from the joint 67 is a stop ring 69 which is spaced a short distance from the internal surface of the spindle 47 to permit a small angular movement of the spindle 63 at the joint 67. A spring pin 71 passes with a close fit through the inner end of the spindle 63, the joint 67, and through helical slots 72 in the spindle 47 and helical slots 73 in a sleeve 74.

The sleeve 74 is pinned to the spindle 47 by spring pin 75. At its ends the pin 71 locates in the gear wheel carrying sleeve 51 a to which the gear wheel 51 is bolted. Mounted on the pin 71 is a drive key 76 which locates in one of the helical slots 73 of the sleeve 74.

Thus with the gear wheel 51 held fast, axial adjustment of the spindle 63 will cause drive key 76 to move along its helical slot 73 and thus cause rotation of the spindle and hence of the pattern cylinder 49 relatively to the gear wheel 51. Hence accurate registration of pin 52 with tooth "1" of the gear wheel 51 can be effected.

After such registration the assembly is locked in position by a grub screw 77 locking the sleeve 56 to the sleeve 65.

Assuming the sub-frames 21 and 22 to be in their withdrawn position, they are rolled to the position in which the gear wheels 51 are in mesh with the bull gear 5, but the print rollers 39 are still out of contact with the impression cylinder (by a distance of say 4 mm). In this position the latches 129 are engaged over the pins on the side plate 30 as shown. When ready to print, the "print" button is pressed. This operates the pneumatic cylinders 29 to rotate the latches, and thus effect controlled inward movement of the latter to draw the sub-frames 21 and 22 to their "locked-up" operative position. The sub-frames are located at the same time by the mating cup and cone registers 28, eight of which are provided (two are fixed between each side of each sub-frame and the central frame).

The advantages of the printing machine as described above are:1) With the sub-frames rolled away from the impression cylinder access to the print rollers is easy and they can be removed without disturbing the other rollers.

2) Bolt-on guarding can be used on the outside of the machine as routine access to the rollers from the outside is not needed.

3) Quick release of all the print rollers can be obtained by rolling back the print sets by 4 mm. from the locked:up position using the pneumatic cylinder. The print roller gear wheels remain engaged but at extended centres.

4) Rolling back the sub-frames releases the nips at the impression cylinder and bull gear, and disengages the drive to the remaining gears.

Therefore, electrical interlocks are unnecessary for safety reasons but can be provided to allow inching once the sub-frames are released.

5) The two sub-frames can be rolled back independently. This enables the printing units of one sub-frame to be cleaned and changed whilst the remaining printing units are still in use if the number of colours is equal to or less than the number of printing units carried by one subframe.

6) The print roller spindle is designed for a demountable print roller. The print roller can therefore be used on another machine when mounted on the appropriate spindle.

7) The print roll can be arranged to be simply released by unscrewing two hand screws about four turns and sliding back clamp bars.

8) The print roller is directly in front of the operator by providing the access between the impression cylinder and the sub-frames and can be lifted straight out complete with gear and registers.

9) The print roller gears are all pre-marked with register marks, and can be registered with each other without recourse to inching round the bull gear.

10) Only one set of gears per print roll diameter is needed.

11) All gears are inboard of the sides of the sub-frames and automatically made safe when the sub-frames are locked-up.

12) The sub.frames are pneumatically locked up rigidly in the print position for example with a force of 1000 Kg. per side for an air pressure of 4.2 Kglcm2. (70 p.s.i.). This is ten times greater than the normal print pressure.

Referring to Figure 7, in a modification of the print roller described hereinbefore with reference to Figure 4, the end of the spindle 63 supported by the bearing 64 is equipped with friction brakes 78 with means for engaging and disengaging the brakes via a register handle 79 whereby to enable the operator to turn the or each print roller 39 to its correct meshing position when its sub-frame 21 or 22 is moved from its operative position enough to allow rotation of the print roller gear 51 independently of the bull gear 5. The handle 79 has a transverse bore 80 in which two brake pads are slidable and are urged into engagement with the bore of the sleeve 65 by a compression spring 81. The inner end of the handle 79 has a spring pin 82 which is arranged to be pushed by the handle into engagement with one of two V-slots 83 provided in the face of a locking collar 84 non-rotatably mounted on the end of the spindle 63. Thus, the V-slots 83 and pin 82 provide between them a releasable coupling. The print spindle 63 can then be rotated by first pushing and then turning the register handle 79 to bring the appropriate numbered tooth opposite to a tooth space on the bull gear 5 in order that the gears will mesh when the respective sub-frame 21 or 22 is "locked-up". Normally the friction brake pads will prevent the print roller from rotating after setting. When the print machine is started after setting, the register handle 79 starts to turn with the spindle 63 but the axial force component of its "V,' slot 83 pushes the pin 82 out of engagement, and the handle stops rotating.

This prevents further wear of the brake pads and the generation of unnecessary heat.

WHAT WE CLAIM IS: 1. In a printing machine having i) an impression cylinder, ii) a toothed bull gear mounted to rotate with said impression cylinder, iii) a plurality, of printing units, each located at a printing station disposed at intervals around said impression cylinder, each said printing unit comprising a) a printing roller b) means for inking said printing roller, and c) a drive gear, for engagement with said bull gear, mounted to rotate with said printing roller, and iv) means for moving said printing units away from said impression cylinder, so that said printing rollers, together with their associated drive gears, can be removed through the space between said impression cylinder and said printing units when the latter are in the position displaced from said impression cylinder the improvement wherein corresponding teeth of each of said drive gears associated with said printing rollers are identically marked at teeth spacings corresponding to the number of teeth of said bull gear between successive printing stations, so that, when any one of said printing units is mounted at a printing station with that marked tooth of its associated drive gear which corresponds with the number of that printing station in engagement with said bull gear, its associated printing roller is in at least coarse registration with the printing roller of any other printing unit which has been similarly mounted at another printing station.

2. In a printing machine according to claim 1, the improvement wherein said impression cylinder is mounted in a main frame and said printing units are mounted in at least one subframe which is (i) hung on tracks supported by said main frame, and (ii) movable toward or away from said main frame.

3. In a printing machine according to claim 1, the improvement wherein said impression cylinder is mounted in a main frame, said printing units are mounted in at least one subframe which is movable toward or away from said main frame, and wherein the or each subframe has a predetermined position in which each printing roller carried thereon, together with the bull gear and the drive gears associated with each printing roller, are just out of engagement, and including means for drawing the same into engagement at the start of a printing operation.

4. In a printing machine according to claim 3, the improvement wherein a hook-type latch is provided for the or each sub-frame and is mounted on said main frame, said latch being arranged to engage a pin or its associated said sub-frame when the latter is at its said predetermined position, and means to actuate said latch to produce a controlled inward movement to a "locked-up" position in which each printing roller carried by said sub-frame and said impression cylinder, together with the drive gears associated with said printing rollers and said bull gear, are in engagement.

5. In a printing machine according to any preceding claim, the improvement wherein the printing roller and associated drive gear of each said printing unit are mounted on a spindle arrangement which permits adjustment of the relative rotational positions of these two said

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Claims

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8) The print roller is directly in front of the operator by providing the access between the impression cylinder and the sub-frames and can be lifted straight out complete with gear and registers.

9) The print roller gears are all pre-marked with register marks, and can be registered with each other without recourse to inching round the bull gear.

10) Only one set of gears per print roll diameter is needed.

11) All gears are inboard of the sides of the sub-frames and automatically made safe when the sub-frames are locked-up.

12) The sub.frames are pneumatically locked up rigidly in the print position for example with a force of 1000 Kg. per side for an air pressure of 4.2 Kglcm2. (70 p.s.i.). This is ten times greater than the normal print pressure.

Referring to Figure 7, in a modification of the print roller described hereinbefore with reference to Figure 4, the end of the spindle 63 supported by the bearing 64 is equipped with friction brakes 78 with means for engaging and disengaging the brakes via a register handle 79 whereby to enable the operator to turn the or each print roller 39 to its correct meshing position when its sub-frame 21 or 22 is moved from its operative position enough to allow rotation of the print roller gear 51 independently of the bull gear 5. The handle 79 has a transverse bore 80 in which two brake pads are slidable and are urged into engagement with the bore of the sleeve 65 by a compression spring 81. The inner end of the handle 79 has a spring pin 82 which is arranged to be pushed by the handle into engagement with one of two V-slots 83 provided in the face of a locking collar 84 non-rotatably mounted on the end of the spindle 63. Thus, the V-slots 83 and pin 82 provide between them a releasable coupling. The print spindle 63 can then be rotated by first pushing and then turning the register handle 79 to bring the appropriate numbered tooth opposite to a tooth space on the bull gear 5 in order that the gears will mesh when the respective sub-frame 21 or 22 is "locked-up". Normally the friction brake pads will prevent the print roller from rotating after setting. When the print machine is started after setting, the register handle 79 starts to turn with the spindle 63 but the axial force component of its "V,' slot 83 pushes the pin 82 out of engagement, and the handle stops rotating.

This prevents further wear of the brake pads and the generation of unnecessary heat.

WHAT WE CLAIM IS: 1. In a printing machine having i) an impression cylinder, ii) a toothed bull gear mounted to rotate with said impression cylinder, iii) a plurality, of printing units, each located at a printing station disposed at intervals around said impression cylinder, each said printing unit comprising a) a printing roller b) means for inking said printing roller, and c) a drive gear, for engagement with said bull gear, mounted to rotate with said printing roller, and iv) means for moving said printing units away from said impression cylinder, so that said printing rollers, together with their associated drive gears, can be removed through the space between said impression cylinder and said printing units when the latter are in the position displaced from said impression cylinder the improvement wherein corresponding teeth of each of said drive gears associated with said printing rollers are identically marked at teeth spacings corresponding to the number of teeth of said bull gear between successive printing stations, so that, when any one of said printing units is mounted at a printing station with that marked tooth of its associated drive gear which corresponds with the number of that printing station in engagement with said bull gear, its associated printing roller is in at least coarse registration with the printing roller of any other printing unit which has been similarly mounted at another printing station.

2. In a printing machine according to claim 1, the improvement wherein said impression cylinder is mounted in a main frame and said printing units are mounted in at least one subframe which is (i) hung on tracks supported by said main frame, and (ii) movable toward or away from said main frame.

3. In a printing machine according to claim 1, the improvement wherein said impression cylinder is mounted in a main frame, said printing units are mounted in at least one subframe which is movable toward or away from said main frame, and wherein the or each subframe has a predetermined position in which each printing roller carried thereon, together with the bull gear and the drive gears associated with each printing roller, are just out of engagement, and including means for drawing the same into engagement at the start of a printing operation.

4. In a printing machine according to claim 3, the improvement wherein a hook-type latch is provided for the or each sub-frame and is mounted on said main frame, said latch being arranged to engage a pin or its associated said sub-frame when the latter is at its said predetermined position, and means to actuate said latch to produce a controlled inward movement to a "locked-up" position in which each printing roller carried by said sub-frame and said impression cylinder, together with the drive gears associated with said printing rollers and said bull gear, are in engagement.

5. In a printing machine according to any preceding claim, the improvement wherein the printing roller and associated drive gear of each said printing unit are mounted on a spindle arrangement which permits adjustment of the relative rotational positions of these two said

parts to enable exact registration to be achieved.

6. In a printing machine according to claim 5, the improvement further including a registration handle provided for each said printing unit, coupling means for releasably connecting said registration handle to said spindle arrangement, and a friction brake associated with said handle for maintaining the latter in an inoperative position when registration has been achieved.

7. In a printing machine according to claim 5, the improvement wherein the printing roller of each said printing unit is axially slidably mounted on the spindle arrangement, and wherein means are provided for adjusting the axial movement of said roller so as to transversely align said printing roller relative to said impression cylinder.

8. A printing machine constructed, arranged and adapted to operate substantially as hereinbefore described with reference to the accompanying drawings.