EP0048157A1

EP0048157A1 - Labelling frozen food packs

Info

Publication number: EP0048157A1
Application number: EP81304203A
Authority: EP
Inventors: John Edward Gray; Douglas Leonard Radlett
Original assignee: J Sainsbury PLC
Current assignee: J Sainsbury PLC
Priority date: 1980-09-15
Filing date: 1981-09-14
Publication date: 1982-03-24
Also published as: JPS5777432A; NO813124L; FI812824L; FI812824A7; DK410981A

Abstract

A labelling gun for applying labels to frozen food packs comprises transfer means (4) for feeding labels (13) past a printing head (5) to an outlet (8) where paper is peeled from an adhesive coating, and a plasticiser applicator (10) positioned adjacent the outlet (8) so as to be wiped by part of the adhesive surface of each label (13) as it is dispensed.

Description

This invention relates to the labelling of frozen food packs and in particular provides a method of applying labels to frozen food packs and a labelling dispenser for carrying out the method.
Many types of equipment exist for the application of labels but it is usual in supermarkets to use a hand held labelling device such as a gun for applying labels to food packs of all kinds. The usual kind of labelling gun has a roll of labels in strip form which labels have a coating of pressure sensitive adhesive and adhere to a strip of easy release paper. When the trigger of the gun is pressed the printing head prints the price and any other required data on to the uncoated side of each label and the printed label is then fed towards an outlet. Just before the label passes through the outlet, the easy release paper strip is peeled away and the label is ejected beneath a pressure roller by means of which the operator presses the label on to the pack.
A problem exists in applying such labels to frozen food packs which are stored at a "deep freeze" temperature, for example a temperature in the range -15°C to -25⁰C, because the pressure sensitive adhesive which is usually used looses its tackiness at low temperatures of this order and the labels fall off the frozen packs, particularly those wrapped in polyethylene film.
The incorporation of a suitable proportion of a plasticiser or plasticisers into the adhesive coating can ensure that the adhesive remains effective at freezer temperatures over long storage periods. There is also a problem, however, in that at room temperature this plasticised adhesive composition is too mobile. It will soak into the label paper and may exude out of the roll of labels.
According to the invention these problems are overcome by providing a method of applying to a frozen food pack a label which has a coating of pressure sensitive adhesive, comprising applying a plasticiser to the adhesive coating as the label is applied to the pack.
Preferably, the plasticiser is applied to a part of the adhesive coating leaving the leading edge of the label free from plasticiser to assist initial adhesion of the label to the pack. This is to overcome a further problem in that the freshly spread plasticiser on the adhesive has relatively low initial tack to the frozen food pack. The improved adhesion develops thereafter, for example during the next 6 to 12 hours, while the adhesion of the unplasticised coating is deteriorating.
Preferably, the pressure sensitive adhesive is a rubber based adhesive and the plasticiser is a vegetable oil. The plasticiser may be corn oil or groundnut oil, or a mixture thereof.
The invention also comprehends a labelling gun for applying labels to frozen food packs by a method as aforesaid, said gun including means for feeding a strip of labels past a printing head to an outlet where paper is peeled from the adhesive coating of each label as the label is ejected past a pressure roller, and a plasticiser applicator so positioned adjacent the outlet as to be wiped by at least part of the adhesive surface of each label as the label is dispensed past the pressure roller.
Conveniently the dispenser is in the form of a hand held gun.
Preferably the plasticiser applicator is an absorbent pad or other member which is held in a mounting on the gun body with a tip exposed adjacent the pressure roller. In a preferred embodiment, the absorbent pad comprises a felt member having a tip projecting from the mounting and each label passes between the tip and the pressure roller.
The location of the pad may be adjustable to vary the position of the tip relative to the pressure roller.
Preferably the mounting incorporates a plasticiser reservoir adjacent the other end of the absorbent pad.
Preferably the reservoir is closed except for the passage through the pad, the pad permitting inflow of air to the reservoir to replace used plasticiser. The felt is located in the applicator but not compresed so as to prevent the ingress of air as plasticiser is used up.
An embodiment of the invention will now be described, by way of example, with reference to the accompanying drawings in which:

Figure 1 is a schematic diagram of a hand labelling gun according to the invention including a plasticiser applicator adjacent the label outlet,
Figure 2 illustrates diagrammatically the outlet from the gun of Figure 1 showing the ejection of the leading edge of a label from the gun,
Figure 3 is a view similar to Figure 2 showing the pressing of the leading edge of the label on to a food pack, with the adhesive coating of the label wiping the plasticiser applicator, and
Figure 4 is a view similar to Figures 2 and 3 showing the final stage of pressing the label on to the pack.

The hand labelling gun illustrated diagrammatically in Figure 1 is of the usual kind. The gun body includes a handle 1 and trigger 2. A reel of labels in strip form is mounted in the gun body as indicated at 3. Information to be printed on the labels is set into transfer means 4 of a printing head indicated generally at 5. A print roller 6 in the printing head is operated when the trigger 2 is pressed to transfer the price and any other required set data onto the label. The path of the labels, indicated at 7, is past the printing head to an outlet 8 from the gun body. A pressure roller 9 is mounted adjacent to the outlet and is used by the operator to press the ejected label onto the pack which is being labelled.
A plasticiser applicator comprising a housing 11 suitably attached to the gun body adjacent the outlet and an absorbent pad which in this example is a felt member held in the housing 11 which acts as a mounting for the pad. The position of the housing 11 and the extent of projection of the felt pad from the housing 11 is arranged such that a projecting tip 10 of the pad is wiped by most of the adhesive surface of each label as the label, ejected through the outlet 8, is pressed by the pressure roller on to a food pack in the manner to be described. In some cases it may be desirable to arrange for the location of the pad to be adjustable to vary the position of the tip 10 relative to the roller 9. Within the housing 11, there is a small reservoir 12 of plasticiser.
The housing 11 is closed except for the end from which the pad projects so that the only passage to the reservoir 12 is through the pad. The pad is not compressed so that it permits air flow into the reservoir to replace liquid used up from the reservoir.
Figure 2 illustrates a strip of labels 13 each of which has a coating 14 of pressure sensitive adhesive, usually a rubber based adhesive. The labels adhere to a strip 15 of easy release paper. As the labels are fed towards the outlet 8 they are printed in turn by the printing roller 6 as described above. At the outlet there is a guide bar 16 around which the strip 15 of easy release paper is guided so that the labels 13 are stripped in turn from the strip 15 and ejected individually through the outlet between the tip 10 and the pressure roller 9. There is a gap between the felt tip 10 and the pressure roller 9 and the alignment of the bar 16 relative to the tip 10 and roller 9 is such that the leading edge of the label does not contact the felt tip and so remains untreated with plasticiser. This means that when the leading edge of the label is pressed on to a frozen food pack indicated at 17 by the operator, there is initial adhesion of the untreated leading part of the pressure sensitive adhesion coating on to the surface of the frozen food pack which is usually a polyethylene surface.
Usually, the plasticiser is a vegetable oil for example corn oil or groundnut oil which may contain an antioxidant. A small reservoir of the oil, indicated at 12 maintains the felt tip saturated so-that when the pressure roller 9 is causing the leading edge of the ejected label to adhere to the surface of the pack 17, the stiffness of the label as it bends, and the movement of the rear edge of each label towards the tip 10 as it is separated from the strip 15, ensures that the label crosses the gap between the pressure roller and the felt tip, for example a 1mm gap, and as the operator moves the gun downwardly, the rest of the adhesive coating of a label wipes against the felt tip 10, so that the plasticiser oil is applied to it and is then rolled on to the surface of the food pack as indicated in Figure 4.
The leading 3 or 4 mm of the adhesive coating of the label which is uncoated by the plasticiser is sufficient to provide initial adhesion of the label to the food pack. The extent of leading edge which is uncoated by plasticiser may be varied to suit the label application.
The rest of the adhesive coating develops its adhesion to the food pack over an initial period of, for example, from 6 to 12 hours as the plasticiser oil penetrates into the pressure sensitive adhesive.
The presence of the plasticiser in the coating ensures that the adhesive maintains its tackiness at the low "deep freeze" temperatures and the labels remain adhered to the frozen food packs over long storage periods.
Other plasticisers may be employed, for example the class of liquids referred to as high boiling point esters, for example di-2-ethyl hexyl phthalate or sebacate, or mineral oils.
The plasticiser applicator described above is formed as a unit which may be readily attached by suitable fixing means to the body of the gun, and may be removed if necessary to permit normal conventional operation of the gun.

Claims

1. A method of applying to a frozen food pack a label which has a coating of pressure sensitive adhesive, characterised by applying a plasticiser to the adhesive coating as the label is applied to the pack.

2. A method according to claim 1 further characterised by applying the plasticiser to a part of the adhesive coating leaving the leading edge of the label free from plasticiser to assist initial adhesion of the label to the pack.

3. A method according to claim 1 or claim 2, further characterised in that the pressure sensitive adhesive is a rubber based adhesive and the plasticiser is a vegetable oil.

4. A method according to claim 3, further characterised in that the plasticiser is corn oil or groundnut oil.

5. A labelling gun for applying labels to frozen food packs by a method according to claim 1, said gun including means for feeding a strip of labels past a printing head to an outlet where paper is peeled from the adhesive coating of each label as the label is ejected past a pressure roller, and characterised by a plasticiser applicator (10,11) so positioned adjacent the outlet (8) as to be wiped by at least part of the adhesive surface of each label (13) as the label is dispensed past the pressure roller (9).

6. A labelling gun according to claim 5, further characterised in that the plasticiser applicator is an absorbent pad or other member which is held in a mounting (11) on the gun body with a tip (10) exposed adjacent the pressure roller (9).

7. A labelling gun according to claim 6, further characterised in that the absorbent pad comprises a felt member having a tip (10) projecting from the mounting (11) and each label (13) passes between the tip (10) and the pressure roller (9).

8. A labelling gun according to claim 6 or claim 7, further characterised in that the location of the pad is adjustable to vary the position of the tip (10) relative to the pressure roller (9).

9. A labelling gun according to any one of claims 6 to 8, further characterised in that the mounting incorporates a plasticiser reservoir (12) adjacent the other end of the absorbent pad.

10. A labelling gun according to claim 9, further characterised in that the reservoir (12) is closed except for the passage through the pad, the pad permitting inflow of air to the reservoir to replace used plasticiser.