EP1156931A1

EP1156931A1 - Adhesive application station for printed products

Info

Publication number: EP1156931A1
Application number: EP00904782A
Authority: EP
Inventors: Walter Baltensperger
Original assignee: Sogno AG
Current assignee: Sogno AG
Priority date: 1999-03-01
Filing date: 2000-02-25
Publication date: 2001-11-28
Anticipated expiration: 2020-02-25
Also published as: US6695031B1; WO2000051826A1; EP1033262A1; EP1156931B1; DE50001097D1; ATE231076T1; AU2655600A

Abstract

The adhesive-applicator unit incorporates an applicator-head (12) for the adhesive and a slide surface (16) for the printed products (10). A thrust piece (22,28) for the printed products is situated on each side of the slide surface. A slot-shaped nozzle for the adhesive extends over the entire width of the slide surface. An adhesive-accumulator is in the form of a pressure compartment. At least one side thrust piece (22,26,32) inside a narrow tolerance range of different thicknesses for the stacked printed products is in the form of side guide surfaces. A movable thrust piece (26,32) always covers the outlet slit (20) of the slot-shaped nozzle.

Description

Glue application station for printed products

The invention relates to an adhesive application station for binding stacked printed products by means of a flowable or liquefiable adhesive, which application station has an application head for the adhesive with a sliding surface for the printed products, a stop for these printed products on both sides of this sliding surface and one over the entire width of the Sliding surface extending slot nozzle for the adhesive, an adhesive reservoir designed as a pressure chamber and means for generating a pressure in the adhesive reservoir.

All types of printed matter for the production of books, magazines, brochures and the like are initially stacked and fixed in a holder. Then the so-called back surface is milled flat and roughened at the same time. The adhesive that is subsequently applied can be better absorbed. If the adhesive is insufficiently absorbed, the binding quality is poor, the bound printed products fall apart during use or individual sheets come loose. The applied adhesive layer not only has to bind every single page firmly, but also has to be so elastic that it is easy to leaf through the bound printed products.

The originally practiced application of an adhesive with a brush or an equivalent medium has been simplified with advancement so that the prepared back surface of a stack can be pulled over at least one roller immersed in an adhesive bath. However, this open system also has the disadvantage that, for example in the case of a moisture-reactive polyurethane adhesive, the action of air and heat changes the chemical and physical properties. The same or similar problems can arise with all known adhesives, which can be used as cold glue, hot glue or hot melt (thermoplastic adhesive). For economic and ecological considerations, for example, aqueous polyurethane dispersions, which are briefly called PU dispersions, have proven advantageous. PU is a group of high-molecular materials that are produced by polyaddition of diisocyanates and bi- or multi-functional hydroxyl compounds. In their molecules, the basic building blocks are connected by the urethane group (-NH-COO-). Depending on the chemical nature of the starting compounds used, polyurethanes with linear, branched or crosslinked macromolecules can be obtained. Linear polyurethanes are thermoplastic materials that have found a wide range of uses. Only cross-linked, elastomeric polyurethanes, which are suitable as elastic, water and heat-resistant adhesives, are of interest here.

Glue application stations are known which work with slot nozzles. The prepared back surface of a stack of printed products is drawn between two stops over a sliding surface with an exit slot for the adhesive. The slot nozzle releases adhesive during this short time. Although stacks with the same number of printed products are drawn through in succession, they are not exactly the same width. In special cases, the different stack widths can deviate by up to approximately + 1 mm. Even in the area of one and the same stack, width differences in the range of a few tenths of a millimeter can occur. In practice, this always leads to problems, for example with glue cords on the bound printed product.

EP, A1 describes an adhesive application station with two jaws which can be manually adjusted to different stack heights and which form the lateral guide jaws. In the case of slightly different stack heights, at least one screw has to be adjusted or space between the jaws and the stack has to be accepted. This has a greater effort or the formation of ugly glue lines. To eliminate these disadvantages, a sealing block is used in the jaws.

The object of the invention is therefore to create an adhesive application station for binding stacked printed products of the type mentioned at the outset, which eliminates the problems with the different stack widths.

The object is achieved according to the invention in that at least one lateral stop is designed as a lateral guide surface which automatically compensates for different thicknesses of the stacked printed products passing through within a narrow tolerance range, and a stop which can be moved back in this tolerance range always seals on an outlet slot of the slot nozzle for the adhesive rests in the sliding surface. Special and further developing embodiments of the adhesive application station are the subject of dependent claims.

Since a stack always has the same number of printed products that are cut from the same print carrier web, experience shows that the tolerance ranges are very narrow. Even with large stacks they are usually at most about ± 0.5 mm, in exceptional cases at most about ± 1 mm.

In practice, the most economical solution is to design an application head with a fixed stop and a stop resilient within the tolerance range for the stacked printed products to be bound. The supply of the stacks is preferably facilitated in that the guide surfaces narrow in the direction of insertion into the area of the slot nozzle. This can take the form of bevels, but also of appropriately curved surfaces. The stop resilient in the slot direction with a guide surface can be designed according to different variants, regardless of whether a fixed stop is designed or both stops are resilient:

- According to a first variant, a guided slide as a whole can be displaceably resilient on a nozzle block of the application head in the direction of the outlet slot and can form a resilient stop with its guide surface.

- According to a further variant, a suitably cylindrical roller that can be displaced in the slot direction in a positionable holder and has an axis perpendicular to the sliding surface can be a guide surface.

- According to a variant, a slide guided in the slot direction is formed with a correspondingly designed front guide surface. The

The slide is displaceable in the direction of the guide slot, for example against the resistance of a spring or against pneumatic pressure, and is arranged in a hold-down device that can be positioned exactly.

- According to a last variant mentioned here, a leaf spring is arranged on the end face of a positionable holder already mentioned in such a way that it forms a guide surface which is elastically deformable in the slot direction by approximately + 1 mm. Different types of leaf springs are suitable, which simultaneously cover the outlet slot in the tolerance range of approximately ± 1 mm.

As already indicated, the movable stop can be automatically returned, preferably by spring force. In the same way, the movable stop can be pneumatically cushioned. As the necessary tolerance range, as also mentioned, is very narrow and generally only a fraction of a millimeter, the movable stop must be able to be positioned exactly. Furthermore, the movable stop lying on the outlet slot for the adhesive must cover it so well that no glue lines are formed on the bound stack of printed products. Since the stops with the lateral guide surface, apart from the variant with a leaf spring, are solid anyway, this is in principle not a problem. A short insert or a thickening in a leaf spring can also serve this purpose

In the interaction of the outlet slot for the adhesive with a metering shaft arranged directly below it, which e.g. has a continuous diagonal longitudinal slot, the slot nozzle is formed. The metering shaft in turn delimits an adhesive store designed as a pressure chamber, which is arranged in or below the application head and is in direct connection with an adhesive dispenser, for example a pressure vessel. This has the previously unattainable advantage that the adhesive never has air contact from the pressure vessel to the outlet slot in the application head, which prevents the chemical and physical changes mentioned at the beginning.

According to a preferred variant, a directly acting printer stamp of a printing cylinder is provided in a pneumatic pressure accumulator for generating the necessary pressure in the adhesive accumulator. However, the necessary pressure can also be generated hydraulically, electromagnetically or with a spindle.

The pressure can and should be changed in relation to the machine speed.

For the use of a hot glue, in particular a hot melt, at least one heating cartridge is arranged in the glue store, which is expedient is sensor controlled. With the help of a temperature sensor, the adhesive is kept at the temperature required for optimum viscosity.

Each time adhesive is dispensed through the outlet slot, automatic pressure compensation, known per se, takes place, which is integrated in the system with the pneumatic pressure accumulator.

All stops with the guide surfaces for the stacks of printed products to be bound are preferably made of wear-resistant, polished material, because the printing medium, in particular paper, pulled over them acts like an emery cloth. Special steels, hard metals, ceramic materials or cermets are suitable materials for guide surfaces.

The invention is explained in more detail with reference to exemplary embodiments shown in the drawing, which are also the subject of dependent claims. They show schematically:

- Fig. 1 is a schematic diagram of the binding area of an application head

Glue application system in top view, - - FFiigg .. 2 2 a schematic diagram of a printing system with pressure compensation in the

Cut,

3 shows a plan view of an adhesive application station,

4 is a view of FIG. 3,

5 shows a side view of FIG. 3 (from the left), FIG. 6 shows a top view of an application head,

7 shows a nozzle block from FIG. 6,

8 is a side view of FIG. 6 (from the right),

9 shows a fixed stop,

10 shows a hold-down device in top view, FIG. 111 shows a side view of FIG. 10 (from the left),

12 a slide plate in plan view, pulled apart, 13 an adjusting screw for a hold-down device,

14 is a guide block for the adjusting screw, and

15 shows a metering shaft.

1 shows the basic principle of binding stacked printed products 10 on an application head 12 of an adhesive application station 14 (FIGS. 3 to 5). A sliding surface 16 of a nozzle block 18 of the application head 12 is penetrated by a longitudinally extending outlet slot 20 for an adhesive 52 (FIG. 2). In the present case, the slot width s of the outlet slot 20 is approximately 0.2 mm. As a rule, this slot width cannot be changed, but it can also be adjustable.

The sliding surface 16 is laterally delimited by a fixed stop 22 with a first guide surface 24, including a guide 24a, and a hold-down 26 with a second guide surface 28, including a guide 28a for a printed product 10. The hold-down device 26 can be displaced and exactly positioned in the direction of the double arrow 30, which runs parallel to the outlet slot 20. The hold-down device 26 guides a slide 32 which can be pressed into the hold-down device 26 against a resilient force within a narrow tolerance range t in the direction of the double arrow 34, which also runs parallel to the outlet slot 20. The slider 32 has a third guide surface 36 for stacked printed products 10, likewise with a guide 36a. Both this third guide surface 36 and the first guide surface 24 are angled and widen as a guide 24a, 36a against the insertion direction E for stacked printed products 10. The narrow tolerance range t for the slider 32 which can be returned by spring force is limited by a bore 38 in the holding-down device 26 and a bolt 40 which projects from the slider 32 in this bore.

To bind stacked printed products, the holding-down device 26 with the slide 32 is first of all corresponding to the minimum thickness d of the stacked ones Printed products 10 positioned and adjusted with a screw, for example. With a tolerance range of, for example, 0.5 mm for the thicknesses d of the stacked printed products, the width g of the sliding surface 16 is set to the distance d + t, provided the slide 32 is pressed in flush with the second guide surface 28 at maximum tolerance t. The push-in of the slide 32 takes place when stacked printed products 10 are introduced, if these are pushed along guides 24a, 36a of the first and third guide surfaces 24, 36. When the exit slot 20 is reached, the adhesive application begins mechanically, electronically or sensor-controlled and is ended when the printed product 10 leaves the area of the exit slot 20.

Both the hold-down device 26 and the slide 32 seal the outlet slot 20 when and where they rest on the sliding surface 16.

When the stacked printed products 10 are guided over the outlet slot 20, they are pressed by the slide 32 onto the first lateral guide surface 24. In the present case, the second guide surface 28 does not act as such, the stacked printed products 10 slide along the third guide surface 36 with guide 36a. 1, differences in the thickness d of the stacked printed products 10 are automatically compensated for both within the same stack and from stack to stack, an adhesive leak next to the printed products 10 cannot take place, as a result of which not only a loss of adhesive but also that Formation of ugly lines of glue is avoided.

According to a variant of the basic principle, which is not shown, the slide 32 can be omitted and the hold-down device 26 itself can be designed as a stop which can be moved resiliently within the tolerance range. In this case, the stacked printed products 10 slide along the second guide surface 28 with a guide. The functional description of FIG. 1 is supplemented by FIG. 2 drawn in reverse. A slot nozzle 42 is sketched in the application head 12, which comprises the outlet slot 20 shown in FIG. 1 and a metering shaft 44 with a diagonal slot 46 which is guided in a bore of the application head 12. This extends over the length of the outlet slot 20.

Arranged below the metering shaft 44, which can be rotated in the direction of the double arrow 48, is an adhesive reservoir 50, which is designed as a pressure chamber and is filled with a dissolved or melted adhesive 52. A pressure cylinder 56 with a pressure stamp 58 is arranged in a pressure accumulator 54 and can be moved in the direction of the double arrow 60 and projects into the adhesive accumulator 50.

The printing system for the adhesive application shown in FIG. 2 is in the middle position. The diagonal slot 46 communicating with the adhesive is closed.

If stacked printed products 10 (FIG. 1) are guided along the sliding surface 16 which extends over an inclined insertion ramp 62, the control switches the metering shaft 44 as soon as it reaches the outlet slot 20 into the working position shown in dashed lines, the diagonal slot 46 of the metering shaft 44 connects therein Position the adhesive store 50 with the exit slot 20. Immediately after the stacked printed products 10 have left the area of the exit slot 20, the sensor-controlled electronics initiate the rotation of the metering shaft 44 into the rest position, and the supply of adhesive to the exit slot 20 is prevented.

The pressure loss occurring as a result of the adhesive being dispensed in the adhesive store 50 is automatically compensated for by pushing the pressure stamp 58 correspondingly deeper into the adhesive store 50. The pressure in the adhesive material reservoir 50 is determined by the cross-sectional ratio of the pressure cylinder 56 to the pressure stamp 58 and the pressure in an antechamber 64 of the pressure reservoir 54 determined. The pressure in this anteroom is, for example, in the range from 0.7 to 0.8 bar.

Of course, the binding process for the stacked printed products 10 can also be carried out manually or semi-automatically.

A basic design principle of an adhesive application station 14 is shown in FIGS. 3 to 5. The functional division into application head 12, adhesive reservoir 50 (pressure chamber) and pressure reservoir 54 can be seen. The essential individual elements of the application head 12 are shown in detail in FIGS. 6 to 15.

The application head 12 comprises a nozzle block 18 as a carrier, which is designed as a profile or is milled or drilled out of a solid block.

A fixed stop 22 with the first lateral guide surface 24 is fastened at one end to the nozzle block 18. This fixed stop can be positioned within the limits of a short slot 66 without fine adjustment.

A hold-down 26 can be positioned over the area of a much larger elongated hole 68. The second lateral guide surface 28 is formed on the end face of the hold-down device 26. On the end face of the nozzle block 18 opposite the fixed stop 22, a guide block 72 is screwed, which is penetrated by an adjusting screw 74 for the precise positioning of the hold-down device 26. This adjusting screw 74 comprises a knurled nut 76 with an adjusting scale 78, which can also be designed as a vernier. Of course, according to further variants, not shown, the hold-down device 26 can also be automatically positioned using other means known per se, for example using a linear motor, stepper motor, hydraulic or pneumatic means. In a corresponding bore of the nozzle block 18 there is a metering shaft 44 which forms the slot nozzle 42 with the outlet slot 20 and which can be actuated manually or automatically by a pivotable lever 80.

The application head 12 is screwed and sealed directly with a separate adhesive store 50 designed as a pressure chamber. A filler neck 82 for the adhesive reservoir 50 has an external thread and can thus be connected directly to a replaceable, larger adhesive reservoir, for example a barrel pump. This ensures that the adhesive is absolutely free of air. The prevention of the contact of adhesive with air, which is aimed at according to the invention, has been achieved.

The pressure accumulator 54 is connected to the adhesive accumulator 50 via four spacer tubes 84. A bore 86 for compressed air is indicated in FIG. 4, which includes the usual connection fittings, not shown. The pressure medium is guided into an antechamber (64 in FIG. 2) and acts on a pressure cylinder 56, indicated by dashed lines, which transfers the pressure, multiplied by the area, via a pressure stamp 58 into the adhesive store 50.

In Fig. 6 an application head 12 is shown in plan view, it essentially corresponds - but reversed - Fig. 3. For clarity, the fastening screws for the fixed stop 22 and the hold-down 26 are missing, there are only the holes 88.90 for bolts recognizable in the elongated holes 66, 68.

6 shows not only the outlet slot 20 for the adhesive in the longitudinal direction, but also longitudinal guide elements. The sliding surface 16 is angled slightly downward along an edge 92 and thus forms an inclined insertion ramp 62 for easier insertion of the stacked printed products. A hardly noticeable first gradation 94 and a larger gradation 96 also serve for easier attachment of the hold-down 26, the fixed stop 22 and the guide block 72.

The width g of the sliding surface 16 is practically set to the maximum possible value. It could be increased a little by moving the fixed stop 22. The minimum width g of the sliding surface 16 is limited by the length of the elongated holes 66 and in particular 68.

A set screw 98 can be seen in the hold-down device 26. With this, the spring force of the slide 32 guided by the hold-down device 26 (FIG. 1) can be adjusted.

7 shows a nozzle block 18 without additional elements. It corresponds essentially to FIG. 6. However, no first step 94 is designed as a guide element. This ensures an improved sliding surface 16. The bore 100 with an internal thread serves to receive a fastening screw for the guide block 72.

The side view of FIG. 6 shown in FIG. 8 (from the right) shows hatched the end face of the nozzle block 18. Below the guide block 72 with the knurled nut 76, part of the adjusting plate 70 and at the bottom part of the hold-down device 26 are visible.

The pivotably mounted metering shaft 44 can be seen in the reinforced face of the nozzle block 18, its pivot lever (80 in FIG. 4) has been omitted for the sake of clarity.

Furthermore, a heating cartridge 102 and a temperature sensor 104 are held in the nozzle block 18, which are used to set the correct adhesive temperature in the application head 12.

Electrical cables, distributors and the like can be see components are stored.

A hold-down 26 with an integrated slide 32 is shown in FIGS. 10, 11 and 12. FIG. 10 shows the slider 32 projecting about 0.4 mm with the third lateral guide 36 which, according to FIG. 1, is slightly angled to form the third guide 36a. The slide 32 can be pressed against the resistance of a spiral spring 106 into the hold-down device 26 until the second guide surface 28 is flush with the third guide surface 36. The stroke restriction of the slide 32 is ensured, as already mentioned, by the bolt 40 in the bore 38. The hold-down device 26 is penetrated in the longitudinal direction by a bore 108, which creates space for the adjusting screw 70.

The second guide surface 28 of the hold-down device 26 is visible in FIG. 11. The second guide surface 28 is slightly angled around an edge 110 to form a guide 26a; together with the guide 24a of the first guide surface 24 of the fixed stop 22 (FIG. 9), this results in a wider introduction opening for the stacked printed products. The slide 32 or its third guide surface 36 is also angled around a displaced edge 112. For better guidance in the hold-down device 26, the slide 32 has a flat longitudinal groove 114 of shallow depth.

As shown in FIG. 12, the slide 32 has a bore 116 with an internal thread, into which a spiral spring 116 and a corresponding ball 118 are pushed. The spring can be preloaded with a set screw 98.

13 and 14 show an adjusting screw 74 with knurled nut 76 and graduation 78 together with the associated guide block 72 with a corresponding bore 120 with an internal thread. A shaft lock 122 is also indicated. A metering shaft 44 shown in FIG. 15 is equipped at one end with a shaft lock 122 and at the other end a pivoting lever 80 is attached for the manual or mechanical application of a torque. An Allen screw 126, which is secured with its tip in a conical depression of the metering shaft 44, prevents the lever 80 from turning empty.

In the left area of the metering shaft, a longitudinal groove is cut out, which functionally corresponds to a diagonal slot 46 (FIG. 2). A radial channel 124 is also provided, which secures the supply of adhesive when the metering shaft is in the working position.

Claims

claims

1. adhesive application station (14) for binding stacked printed products (10) by means of a flowable or liquefiable adhesive (52), which application station (14)

- An application head (12) for the adhesive (52) with a sliding surface (16) for the printed products (10), on both sides of this sliding surface (16) each have a stop (22, 26) for these printed products (10) and one over the full width (g) of the sliding surface (16) extending slot nozzle (42) for the adhesive (52),

- An adhesive store (50) designed as a pressure chamber

Comprises means for generating a pressure in the adhesive store (50),

characterized in that

at least one lateral stop (22, 26, 32) is designed as a lateral guide surface (24, 24a, 28, 28a or 36, 36a) that automatically compensates for different thicknesses (d) of the continuous stacked printed products (10) within a narrow tolerance range (t) , and a stop (26 or 32) which can be moved back in this tolerance range (t) always rests sealingly on an outlet slot (20) of the slot nozzle (42) for the adhesive (52) in the sliding surface (16).

2. adhesive application station (14) according to claim 1, characterized in that the tolerance range (t) is up to about ± 1 mm, preferably up to about + 0.5 mm.

3. adhesive application station (14) according to claim 1 or 2, characterized in that a fixed stop (22) and a resilient stop (26 or 32) is formed within the tolerance range (t), preferably with lateral guide surfaces (24, 28, 36) narrowing in the direction of insertion (E) of the printed products (10) as guides (24a, 28a, 36a).

4. adhesive application station (14) according to one of claims 1 to 3, characterized in that the resilient in the slot direction stop (26 or 32) with the guide surface (28,28a, 36,36a) mechanically as a whole on a nozzle block (18) or pneumatically guided slide, a roller guided in a positionable holder, a slide (32) guided in a positionable hold-down device (26) or a leaf spring guided in a positionable holder.

5. adhesive application station (14) according to claim 4, characterized in that the movable stop with preferably adjustable spring force or pneumatically can be returned.

6. adhesive application station (14) according to any one of claims 1 to 5, characterized in that the width (s) of the outlet slot (20) is adjustable.

7. adhesive application station (14) according to any one of claims 1 to 6, characterized in that the slot nozzle (42) comprises a directly below the outlet slot (20) manually or controlled machine rotatable metering shaft (44) with a longitudinal slot (46), which extends over the entire length of the outlet slot (20) and, in the working position of the metering shaft (44), communicatively connects the outlet slot (20) with the directly adjoining adhesive reservoir (50).

8. adhesive application station (14) according to claim 7, characterized in that an integrated pressure accumulator (54) with directly on the in or below the application head (12) arranged adhesive accumulator (50) kenden means is formed and thus ensures automatic pressure compensation after each release of adhesive.

9. adhesive application station (14) according to claim 8, characterized in that a pressure cylinder (56) by means of the pressure accumulator (54) via a pressure stamp (58) acts directly on the adhesive (52) in the adhesive store (50).

10. adhesive application station (14) according to one of claims 1 to 9, characterized in that at least one sensor-controlled heating cartridge (102) is arranged in the application head (12) and / or in the adhesive store (50).