A label printing machine

Abstract

 A label printing machine, especially but not exclusively a hot foil label printing machine, has a feed assembly for stepwise indexing label stock in web form through the machine. The feed assembly comprises a web brake (39,40) and a web-indexing roller (37) and pressure roller (41) combination, whereof the web brake (39, 40) and pressure roller (41) are each controlled by lever (44, 51) means operated by a separate cam (42, 43). The arrangement is such that when the brake (39, 40) is open the indexing roller (37) with the pressure roller (41) in nipped relationship steps the web through the machine and when the brake (39, 40) is on the indexing roller (37) contra-rotates with the pressure roller (47) spaced therefrom.

Description

[0001] This invention relates to a label printing machine, particularly to a hot foil label printing machine.

[0002] It is an object of the present invention to provide such a machine incorporating primarily improvements in the assembly for feeding label stock through the machine; and secondarily in the threading of the foil through the machine between foil supply and foil rewind locations; and in ensuring a controllable constant tension in the label stock, laminate and foil as they are fed stepwise through the machine.

[0003] According to the present invention there is provided, a label printing machine, especially but not exclusively a hot foil label printing machine, the machine comprising a feed assembly for stepwise indexing label stock in web form through the machine, and including a web brake and a web-indexing roller and pressure roller combination, the web brake and pressure roller each being controlled by lever means operated by a separate cam, the arrangement being such that when the brake is open the indexing roller with the pressure roller in nipped relationship steps the web through the machine and when the brake is on the indexing roller contra-rotates with the pressure roller spaced therefrom.

[0004] The indexing roller is indexed from the pressure roller cam by a length-adjustable lever means, the length adjustment determining the amount of indexing of the web.

[0005] Preferably, the hot foil label printing machine includes a foil feeder assembly comprising a foil feeder track, a flexible element housed within and movable along the track, the flexible element being securable to an end of foil adjacent the foil supply, and a winding mechanism to which the flexible element is secured and which serves to pull the flexible element and the foil along the track to a foil rewind.

[0006] Preferably also, the label printing machine includes a web tensioning device comprising a dancer roller carried by a pivotal, length-adjustable, spring-return arm adapted to operate a cam-controlled brake, either to release or apply the latter depending on whether the web is being wound on or wound off a reel during indexing.

[0007] An embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which:-

Fig. 1 is a longitudinal flow diagram of label stock and laminate through a hot foil label printing machine;

Fig. 2 is a transverse flow diagram of foil through the same machine;

Figs. 3 and 4 are respectively a side view and an end view of a foil feeder assembly;

Figs. 5 and 6 are respectively a side view and an end view of an indexing mechanism for label stock and laminate; and

Fig. 7 is a diagrammatic view of a dancer roller tensioning mechanism.

[0008] Referring to Figs. 1 and 2, the hot foil label printing machine comprises a label stock supply 10 from which web 11 passes to a label rewind reel 12 via a dancer roller tensioning mechanism 13, a hot platen printing device 14 where the web 11 meets with the foil 15 (see Fig. 2), a roller assembly 16 where the printed web 11 and a transparent laminate 17 bond together, a cutting device 18 through which the bonded web 11 and laminate 17 pass, an indexing roller assembly 19, a stripper assembly 20 where waste label material 21 is removed for passage to a waste label collection reel 22, and a second dancer roller tensioning mechanism 23. The laminate 17 is delivered to the bonding roller assembly 16 from a laminate supply 24 through a dancer roller tensioning mechanism 25, the backing material 26 of the laminate 17 being separated therefrom at this location and delivered to a laminate waste collection reel 27.

[0009] The foil 15 passes from a foil supply 28 through the hot platen printing device 14 and through an indexing roller assembly 29 to a foil rewind reel 30.

[0010] A foil feed assembly is provided which permits an operator to thread the foil 15 between supply 28 and rewind 30 without risk of contact with the hot platen printing device 14. This assembly consists of a track 31 which would be located at position A of Fig. 2. A steel tape (not shown) passes through this track 31 and at one end is adapted to grip the foil 15 adjacent the foil supply 28 while its other end is acted upon by a pressure roller 32 which cooperates with a guide roller 33, the pressure roller 32 being rotatable by means of a handwheel 34. These are supported in a bracket 35 which also supports a stop 36 for the tape., the latter being hand threaded via the indexing roller assembly 29 to the rewind reel 30.

[0011] The indexing roller assembly 19, according to the invention, comprises an indexing roller 37 rotatably carried between plates 38 and a braking roller 39 which cooperates with a plate 40.

[0012] A pressure roller 41 cooperates with the indexing roller 37.

[0013] There are two cams 42, 43, cam 42 operating the indexing roller 37 and the pressure roller 41 and cam 43 operating the brake roller 39.

[0014] Cam 42 cooperates with a follower 42A which is connected to a lever 44 which serves to move the pressure roller 41 into and out of nipped relationship with the indexing roller 37. The pressure roller 41 is carried between arms 45 pivotally mounted at 46.

[0015] The indexing roller 37 is driven clockwise from cam 42 by a bellcrank lever 47 adjustably engaging in the slot 48 of a pivotal bar 49 to which is secured a bellcrank lever 50 secured to the axis of rotation of the indexing roller 37.

[0016] The position of securement of the bellcrank lever 47 to the bar 49 determines the length of indexing stroke of the indexing roller 37.

[0017] The cam 43 via cam followers 41A, 42A and pivotal lever 51 serves to move the braking roller 39 towards and away from the plate 40.

[0018] When indexing, the braking roller 39 is spaced from the plate 40 and the pressure roller 41 and indexing roller 37 are in nipped relationship, the web 15 being gripped by the braking roller 39 and the plate 40 just as indexing ceases and pressure roller 41 is pivoted away from nipped relationship with the indexing roller 37. The web 15 is thus always gripped either by braking roller 39 or pressure roller 41.

[0019] A constant-tension dancer roller arrangement is provided where there is indexing of web material (i.e. label stock and laminate). It comprises a dancer roller 52 carried by a length-adjustable arm 53 which operates a cam 54 to apply or release a drum brake 55 applied or released in synchronism with indexing of the machine. A slipping clutch cooperates with the brake 55. A return spring 56 is secured to the arm 53 by a strap 57 passing around a pin 58.

[0020] There is a relationship between arm length and cam position. With the arm at 25° to the vertical, the point of the cam should trail from the vertical by 45⁰ as shown. The arm length at label rewind, for example, is 61 inches while at laminate unwind it is, for example, 5 inches.

[0021] A spring balance is employed to set the desired constant tension and with the figures given above and the brake and clutch set at 40 lb. ins. (brake set first) the spring balance force is 8.4 lbs at the label rewind. At laminate unwind the set pressure is 32 lb. ins. with a spring balance force of 6.7 lbs.

[0022] Means is provided at the slotted bar of the indexing roller operating levers to provide a digital read-out on the machine thereby indicating to the operator whether or not machine registration is correct.

Claims

1. A label printing machine, especially but not exclusively a hot foil label printing machine, the machine comprising a feed assembly for stepwise indexing label stock in web form through the machine, and including a web brake and a web-indexing roller and pressure roller combination, the web brake and pressure roller each being controlled by lever means operated by a separate cam, the arrangement being such that when the brake is open the indexing roller with the pressure roller in nipped relationship steps the web through the machine and when the brake is on the indexing roller contra-rotates with the pressure roller spaced therefrom.

2. A machine as claimed in Claim 1, in which the indexing roller is indexed from the pressure roller cam by a length-adjustable lever means, the length adjustment determining the amount of indexing of the web.

3. A machine as claimed in Claim 1 or 2 comprising a foil feeder assembly comprising a foil feeder track, a flexible element housed within and movable along the track, the flexible element being securable to an end of foil adjacent the foil supply, and a winding mechanism to which the flexible element is secured and which serves to pull the flexible element and the foil along the track to a foil rewind.

4. A machine as claimed in any one of Claims 1 to 3 comprising a web tensioning device comprising a dancer roller carried by a pivotal, length-adjustable spring-return arm adapted to operate a cam-controlled brake, either to release or apply the latter depending on whether the web is being wound on or wound off a reel during indexing.

Drawing