GLUING STATION AND METHOD FOR OPERATING SUCH A GLUING STATION

Abstract

A gluing station for applying glue to product elements guided in a product stream is intended to permit continuation of the production process and gluing of the product elements in a particularly simple and reliable manner even after a temporary machine stop or production standstill. For this purpose, according to the invention, a moistening system is assigned to a glue application roller that can roll on the product stream. During operation of the gluing station, in the event of a stopped product stream, the glue application roller is pivoted away from the product stream and the transfer roller for the duration of the standstill and is kept rotating, whereby the surface of the glue application roller is moistened.

Claims

1. A gluing station for applying glue to product elements guided in a product stream, having a transfer roller to which glue held in a glue trough is transferred during operation of the gluing station, and having a glue application roller which can be pivoted onto the transfer roller, wherein the glue application roller in a swung-in state rolls on the product stream formed by the product elements, and wherein a moistening agent can be supplied to a surface of the glue application roller via an associated moistening system in a state swung away from the transfer roller.

2. The gluing station of claim 1, the glue application roller of which is designed as a rubber roller.

3. The gluing station of claim 1, a humidification system of which comprises a water nebulizer.

4. The gluing station of claim 3, the water nebulizer of which comprises an ultrasonic atomizer.

5. The gluing station of claim 1, wherein an outlet nozzle of the moistening system is positioned close to the surface of the glue application roller.

6. The gluing station of claim 1, wherein an outlet nozzle of the moistening system is configured such that water mist can be supplied to the surface of the glue application roller in laminar flow.

7. The gluing station of claim 3, the water nebulizer of which has a collection chamber for excess water mist in a mist outlet area.

8. A method of operating the gluing station of claim 1, wherein in an event of a temporarily stopped product flow for duration of the stoppage, the glue application roller is pivoted away from both the product flow and the transfer roller and is kept further rotating, thereby moistening the surface of the glue application roller.

9. The method of claim 8, wherein a water-based dextrin glue is used as the glue.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0020] An embodiment of the invention is explained in more detail with reference to a drawing. Therein show:

[0021] FIG. 1 production line for manufacturing envelopes, and

[0022] FIG. 2 gluing station of the production line shown in FIG. 1.

[0023] Identical parts are marked with the same reference signs in both figures.

DETAILED DESCRIPTION

[0024] The production line 1 shown in FIG. 1 is intended for the production of letter bags, envelopes 2 and/or mailing bags, each provided with a closure flap with adhesive zones. The production line 1 comprises several stations of conventional design, of which only parts of a bottom flap folding station 4 and a side flap folding station 6 are shown schematically in FIG. 1. From the side flap folding station 6, the envelopes 2 (and the like) enter a staggering station 8 with a staggering wheel 10. With the aid of the staggering wheel 10, the individually arriving products, envelopes 2 or mailing bags, are pushed together so that they overlap one another and are then transported further into a gluing or gluing station 20, forming a product stream 12, in the example a shingled stream. In the gluing station 20, a glue or adhesive 22 is applied to the insides of the flaps of the envelopes 2 or mailing pockets. Products are then pulled apart slightly so that the glue does not stick the products together. The adhesive 22 forming an adhesive zone is then dried in the drying section for further processing.

[0025] The gluing station 20 is shown enlarged in FIG. 2. It includes a glue trough 28 in which the glue or adhesive 22 is held ready for processing. A scoop roller 30 is partially immersed in the glue 22 held in the glue trough 28, so that when the scoop roller 30 rotates about its longitudinal axis, a partial amount of the glue 22 adheres to the surface and is thus conveyed out of the glue trough 28. Rolling on the surface of the scoop roller 30 is a transfer roller 32, to which the glue 22 adhering to the surface of the scoop roller 30 is transferred. A glue application roller 34 in the form of a rubber roller can be pivoted onto the transfer roller 32 and, when pivoted in, also rolls on the product stream 12 formed by the product elements, in this example the envelopes 2. The product stream 12 is thereby guided past the gluing station 20 in the transport direction indicated by the arrow 36, so that the glue 22 located on the surface of the glue application roller 34 is transferred to the desired positions of the product elements or envelopes 2.

[0026] In the event of a machine or production stop, in which the further transport of the product stream 12 in the transport direction is temporarily interrupted, for example as a result of a production error, a process malfunction or machine set-up work, the glue application roller 34 is temporarily swung out from the working position shown in FIG. 2 and separated from the transfer roller. In this case, the so-called gluing unit, i.e. the ensemble of scoop roller 30 and transfer roller 32, is kept in motion as required or unchanged by a continuation motor not shown in greater detail, and is continuously supplied with fresh glue 22, so that here drying of the glue 22 is prevented by the continuous material exchange.

[0027] The glue application station 20 is now specifically designed so that, in such a state of temporary production stop, the drying of the glue 22 located on the surface of the glue application roller 34 is also prevented in a particularly simple and reliable manner, so that, after termination of the temporary production stop, a particularly efficient and simple continuation or resumption of the production process can take place. For this purpose, during the production stop, an as-needed, preferably continuous, uniform moistening of the glue 22 located on the surface of the rotating glue application roller 34 is provided. To make this possible, the gluing station 20 is provided with a moistening system 38 associated with the glue application roller 34.

[0028] With regard to its components and their positioning within the gluing station 20, the moistening system 38 is thereby quite preferably designed for a demand-oriented supply of a moistening agent, in the embodiment example water, to the surface of the glue application roller 34. In the embodiment example, this supply is to take place as a water mist according to a particularly preferred embodiment of the invention, in order to ensure a resource-saving and yet very efficient use of the moistening agent. For this purpose, the humidification system 38 comprises a water nebulizer 40.

[0029] In this case, the water nebulizer 40 with its outlet nozzle 44 is suitable with regard to the intended mode of operation and is positioned close to the surface of the glue application roller 34, so that an efficient supply of the generated water mist to the glue application roller 34 is possible. In the particularly preferred embodiment shown, the water nebulizer 40 comprises an ultrasonic atomizer 42 as the actual nebulizing element.

[0030] In order to enable the preferred desired delivery of the generated water mist to the surface of the glue application roller 34 in laminar flow, the moistening system 38 is also provided with or combined with a suitably selected and dimensioned outlet nozzle 44 for the water mist. The water mist generated by the ultrasonic atomizer 42 is transported to the outlet nozzle 44 by a blower 48 and a suitably selected hose 50.

[0031] In addition, a collection chamber 46 for excess water mist is arranged in the mist outlet area downstream of the outlet nozzle 44. This serves to prevent any water mist that may bounce off the surface of the glue application roller 34 from escaping directly into the machine environment at the outlet of the nozzle 44, but to allow it to remain as far as possible on the glue application roller 34 or on the glue 22.

[0032] During operation of the production line 1 or of the gluing station 20, in the event of a stopped product flow 12, the glue application roller 34 is pivoted away from the product flow 12 and from the transfer roller 32 for the duration of the standstill and is further kept in rotation, the surface of the glue application roller 34 being moistened. When the production line 1 is restarted, the glue application roller 34 is preferably first glued for a few revolutions before it is pivoted towards the transport section. This is to ensure optimum glue consistency

[0033] In the embodiment and in a particularly preferred embodiment, a water-based, remoistenable dextrin glue is used as the glue 22. When drying begins, this exhibits a significantly increased adhesive effect compared to the still liquid state. It can also be reactivated or removed from non-absorbent surfaces by adding water when drying begins. Its viscosity is preferably approx. 4450 mPA*s, its solids content approx. 67% and its density 1.16 g/ml.

LIST OF REFERENCE SIGNS

[0034] 1 Production plant [0035] 2 Envelopes [0036] 4 Floor flap folding station [0037] 6 Side flap folding station [0038] 8 Relay station [0039] 10 Relay wheel [0040] 12 Product flow [0041] 20 Elimate station [0042] 22 Glue, adhesive [0043] 28 Glue tub [0044] 30 Scoop roller [0045] 32 Transfer roller [0046] 34 Glue application roller [0047] 36 Arrow [0048] 38 Humidification system [0049] 40 Water nebulizer [0050] 42 Ultrasonic atomizer [0051] 44 Outlet nozzle [0052] 46 Collecting chamber [0053] 48 Fan [0054] 50 Hose