WO2016042496A1

WO2016042496A1 - Decorating apparatus

Info

Publication number: WO2016042496A1
Application number: PCT/IB2015/057126
Authority: WO
Inventors: Franco Stefani
Original assignee: System S.P.A.
Priority date: 2014-09-19
Filing date: 2015-09-16
Publication date: 2016-03-24

Abstract

A decorating apparatus for decorating objects (5), in the form of slabs or bars, comprises an arrangement of decorating machines (10) including one or more decorating machines (2A, 2B, 2C), each decorating machine (2A, 2B, 2C) being provided with a decorating head (4 A, 4B, 4C) and a conveying device (3 A, 3B, 3C) including support surface means (11) suitable for supporting and conveying the objects (5) to be decorated below the decorating head (4) along an advancing direction (F); the decorating apparatus further comprises an auxiliary advancing element (16) suitable for receiving and supporting the objects (5) to be decorated, the auxiliary advancing clement ( 16) being draggable by the support surface means (11) along the advancing direction (F) through the arrangement of decorating machines (10).

Description

Decorating apparatus

The invention relates to a decorating apparatus for decorating objects in the form of slabs or bars of the type comprising one or more decorating machines.

Numerous techniques are known for decorating objects in the form of slabs or bars, such as ink-jet printing technique. With this printing technique, it is possible to apply an image of any type to a semifinished product, for example a single colour, a drawing, or a photographic image, this permitting a substantially unlimited range of decorations.

As it is known, the desired image is obtained by superimposing or combining layers of different colours.

As Figure 1A shows, a decorating apparatus 101 of known type comprises one or more decorating units, for example ink jet printing units, each indicated as a printing unit 102, which are arranged one after the other. Each printing unit 102 is provided with a plurality of printing heads 104 and with a conveyor belt 103 for conveying the semifinished products 105 to be decorated below the printing heads 104. Each conveyor belt 103 is substantially aligned with the conveyor belts of the other printing units 102 of the decorating apparatus 101 and is driven by a respective reduction gear M at the same speed as the other conveyor belts. The printing heads 104 of a printing unit 102, after the sensor has detected the presence of the semifinished product, start the synchronised spreading of the colours, which depends on the advancing speed of the conveyor belts and on the dimensions of the semifinished products 105 to be decorated. Each conveyor belt 103 comprises an inlet zone 108 from which the semifinished products 105 enter the printing unit 102 and an outlet zone 109 from which the semifinished products exit the printing unit 102. Between the outlet zone 109 of a conveyor belt 103 and the inlet zone 108 of a further conveyor belt arranged downstream of the first there are passage rollers 107 mounted freely rotatable on a frame that is not shown, which support the semifinished products 105 in transit from one conveyor belt 103 to the other.

One drawback of the known decorating apparatuses disclosed above is that, during transit between one printing unit and the next, the semifinished product in transit can slide at the passage rollers 107 and move with respect to the position that the semifinished product had in the preceding printing unit. Consequently, the decorative layer applied to the subsequent printing unit is staggered with respect to the decorative layer applied in the preceding printing unit, this generating a defective decorated piece, on the surface of which there are undesired zones of overlapping colour or zones lacking in colour, which are also undesired. It should be noted that a shift of even a few hundredths of a millimetre of a second decorative layer applied to a first decorative layer generates a defective image and thus a decorated item that has to be rejected.

If a semifinished product has a small size, in particular has a dimension in the advancing direction of the conveyor belts 103 that is comparable with the distance between the passage rollers 107, the semifinished product, by losing contact with the surface of the conveyor belt, can lose the position or even stop between the passage rollers 107, this causing the loss of centring between the deposited decorative layer and the layer applied by the rest of the printing units.

A further drawback of known apparatuses is that the conveyor belt 103 gets dirty with ink coming from the printing heads 104, which modifies the surface of the conveyor belts 103. This causes a modification to the orientation of the semifinished products on the conveyor belt 103 during conveying, thus modifying centring of the application of the decoration between the various decorating units.

The conveyor belts of the various printing units must therefore be cleaned.

Further decorating apparatuses are known in which instead of a plurality of printing machines a plurality of printing heads is provided that are arranged in succession above a single conveyor belt that conveys the semifinished products to be decorated below the printing heads.

In these decorating apparatuses the semifinished products do not have to be transferred between a plurality of conveyors. Nevertheless, the single conveyor belt, which can also be tens of metres in length, undergoes local elongation that is due to the mass of the semifinished product conveyed by the single conveyor belt, this causing sliding of the conveying surface below the semifinished product and a variation in the position of the semifinished product with respect to a reference point taken on the surface of the conveyor itself. As centring of the decoration depends on the reference position, this variation of the position of the semifinished product causes centring defects in the obtained decoration. This sliding is not predictable or calculable because it varies according to the dimension of the semifinished products loaded on the conveyor belt and to the quantity of semifinished products loaded in a unit of time.

One object of the invention is to improve decorating apparatuses of known type. Another object is to provide a decorating apparatus for decorating semifinished products comprising one or more decorating units in which the risk is eliminated of sliding of the semifinished product in the passage between a printing unit and a subsequent printing unit. Yet another object is to obtain a decorating apparatus for decorating semifinished products that permits the transition between one printing unit and the next printing unit also of semifinished products of small dimensions, preventing the semifinished products from being able to lose position or even stop.

A further object is to obtain a decorating apparatus for decorating semifinished products, which permits constant motion of the semifinished product, with varying of the load lying on the dragging system of the apparatus.

A still further object is to provide a decorating apparatus that enables the surfaces to be cleaned that convey the semifinished products, to a single position.

According to the invention, a decorating apparatus is provided for decorating objects in the form of slabs or bars, comprising an arrangement of decorating machines including one or more decorating machines, each decorating machine being provided with a decorating head and a conveying device including support surface means suitable for supporting and conveying said objects to be decorated below said decorating head along an advancing direction, characterised in that it further comprises an auxiliary advancing element suitable for receiving and supporting said objects to be decorated, said auxiliary advancing element being draggable by said support surface means along said advancing direction through said arrangement of decorating machines.

Owing to the invention, the semifinished products move from one decorating machine to the adjacent one without interruption, thus avoiding all risk of shift or jamming of the semifinished products between one conveying device and the next one.

Further, the support surface means of each conveying device is protected from the auxiliary advancing element, thus preventing the conveying devices getting dirty with ink. In one embodiment, the decorating apparatus comprises a cleaning device for cleaning the auxiliary advancing element.

Owing to the auxiliary advancing element it is possible to use a single cleaning device for the entire arrangement of decorating machines, thus avoiding cleaning the single conveying devices from possible ink that may have exited the decorating heads. The invention can be better understood and implemented with reference to the attached drawings that illustrate some embodiments thereof, by way of non-limiting example, in which:

Figure 1 A is a schematic longitudinal section of a decorating apparatus of the prior art; Figure 2 A is a schematic top view of the decorating apparatus in Figure 1 A;

Figure 1 is a schematic longitudinal section of a decorating apparatus according to the invention;

Figure 2 is a schematic top view of the decorating apparatus in Figure 1 ;

Figure 3 is an enlarged and fragmentary view of support surface means provided in the decorating apparatus in Figure 1 ;

Figure 4 is an enlarged and fragmentary view of an alternative embodiment of the support surface means provided in the decorating apparatus in Figure 1.

With reference to Figures 1 and 2, a decorating apparatus 1 for decorating objects 5 in the form of a slab or bar comprises an arrangement of decorating machines 10. The objects 5 can be ceramic semifinished products that are the precursors of ceramic tiles, slabs or slats or can be glass slabs or slats or wood tables or slats or metal slabs or bars, in particular of aluminium.

The arrangement of decorating machines 10 includes one or more decorating units or machines 2, which are suitable for decorating a substantially flat surface.

Naturally, the number of decorating machines of the arrangement 10, can be the desired number, generally chosen on the basis of the complexity of the decoration that it is desired to obtain. The decorating apparatus 1 can also comprise a single decorating machine.

Each decorating machine 2 is provided with a decorating head 4 and a conveying device 3. The decorating head 4 is an applicator of decorating material, in particular an ink jet printing head or a printing head that applies decorating material other than ink, for example powder material. The decorating head 4 can also be a contact printing head, for example a rotating flexible die such as an engraved elastomeric cylinder or a silkscreen printing cylinder.

The conveying device 3 can be belt conveyor or a roller conveyor, as it will be disclosed with reference to Figure 4.

The conveying device 3 includes support surface means 11 suitable for supporting and conveying the objects 5 to be decorated below the decorating head 4 along an advancing direction F. The decorating apparatus 1 further comprises an auxiliary advancing element 16 suitable for receiving and supporting the objects 5 to be decorated, this auxiliary advancing element 16 being draggable by the support surface means 11 along the advancing direction F through the arrangement of decorating machines 10.

In the illustrated example, the arrangement of decorating machines 10 comprises three printing machine 2 A, 2B, 2C, in particular printing ink jet machines, arranged one after another according to a linear arrangement. The printing machine 2A, 2B, 2C can be structurally the same as one another. The number of printing machines can be the desired number, more or less than three.

Each printing machine 2A, 2B, 2C is provided with a respective printing head 4A, 4B, 4C, each of which, in the illustrated example, comprises four ink jet printing heads 4u, 4v, 4w, 4z, mounted on a common support 22. Each ink jet printing head 4u, 4v, 4w, 4z contains an ink of a preset colour. The number of ink jet printing heads provided in each printing head 4A, 4B, and 4C can be other than four.

As indicated above in general terms, each printing machine 2 A, 2B, 2C is provided with a conveying device 3A, 3B, 3C suitable for conveying the objects 5 to be decorated below the printing head 4A, 4B, 4C, which conveying device conveys the objects 5 by means of the auxiliary advancing element 16.

With reference to Figures 1 and 3, the conveying device 3A, 3B, 3C can be a belt conveyor including a supporting belt 12 wrapped in a loop around a driving roller Rl and around a driven roller R2.

The support surface means 11 comprises an outer surface 13 of an upper branch of the supporting belt 12.

The outer surface 13 of a belt conveyor is substantially aligned with the outer surface of the belt conveyors of the other printing machines 2 A, 2B, 2C. Each driving roller Rl is driven by a respective reduction gear M such that the upper branches of the supporting belts 12 of the various belt conveyors advance substantially at the same speed along the advancing direction F.

In one alternative embodiment of the decorating apparatus 1, which differs from the preceding embodiment by the type of conveying device, at least one conveying device 3A, 3B, 3C can be a roller conveyor, shown in Figure 4. In particular, in Figure 4 two consecutive roller conveyors are shown. The roller conveyor includes supporting rollers 14, which are motor-driven, i.e. driven by a motor by means of a mechanical transmission, for example a chain or belt or other type of known transmission, or rollers, each of which is equipped with a motor. The roller conveyor can further comprise idle rollers in combination with the driven supporting rollers 14. In the embodiment with a roller conveyor, the support surface means 11 comprises a plurality of curved surfaces, each curved surface corresponding to an upper portion 15 of the outer surface of each supporting roller 14. This upper portion 15 extends around the contact line between the supporting roller 14 and the plane tangent to the supporting roller 14. The consecutive roller conveyors of the various conveying devices 3A, 3B, and 3C are arranged such that the upper portions 15 define an advancement plane that is substantially parallel to the advancing direction F. This advancement plane also comprises the outer surface 13, if the decorating apparatus 1 comprises conveying devices of both the types disclosed above. In one embodiment, there is provided a single row of supporting rollers 14 that are parallel to one another, orthogonal or tilted with respect to the advancing direction F. Alternatively, instead of a single row of supporting rollers, the advancement plane can be defined by a plurality of rows of supporting rollers, such rows being adjacent to one another along the width of the decorating apparatus 1 such that in the width of the apparatus at least two adjacent rows can be arranged. Each row of supporting rollers can comprise rollers that are parallel to one another, orthogonal or tilted with respect to the advancing direction F. For example, two adjacent rows can have supporting rollers with opposite slope with respect to the advancing direction F. Also in the embodiment with a roller conveyor, the supporting rollers 14 of each roller conveyor are driven substantially at the same speed; if the decorating apparatus 1 comprises conveying devices of both types, the speed set for the various types of conveyor is the same.

The auxiliary advancing element 16, which supportingly receives the objects 5 to be decorated, during operation of the decorating apparatus 1, is dragged by the support surface means 11 along the advancing direction F through the arrangement of decorating machines 10.

The objects 5 to be decorated rest on the auxiliary advancing element 16, which is in turn supported by each conveying device 3A, 3B, 3C.

The auxiliary advancing element 16 comprises a belt 17 provided with a dragging surface 18 cooperating through friction with the support surface means 11 of each conveying device 3A, 3B, 3C. The belt 17 consists of one or more cloth layers and one or more layers of polymeric material, of which an outer layer of polymeric material defines the dragging surface 18. Also the support surface means 11 consists of polymeric material. In the embodiment in which the conveying device 3 A, 3B, 3C is a belt conveyor, at least the outer surface 13 consists of polymeric material, whereas in the embodiment in which a conveying device 3A, 3B, 3C is a roller conveyor, the respective supporting rollers 14 are rubber-coated, i.e. it is the outer surface of each supporting roller 14 that comprises at least one layer of polymeric material.

The polymeric materials that constitute respectively the dragging surface 18 and the support surface means 11 have to have a certain chemical resistance. Further, the dragging surface 18 has to be easily cleanable. Such polymeric materials have to be chosen in such a manner that between the contact surfaces sufficient friction is generated to enable the supporting belt 12, or the supporting rollers 14, to drag the belt 17 loaded with objects 5, or also unloaded, without reciprocal sliding, when the supporting belt 12 is driven at the desired speed.

Generally, the dragging surface 18 and the support surface means 11 are opaque surfaces. One usable polymeric material that meets the above requirements is polyurethane or a polyurethane based material for both the dragging surface 18 and the support surface means 11.

In the embodiment with belt conveyors, the supporting belt 12, which has to support and drag the auxiliary advancing element 16 loaded with objects 5 to be decorated, is generally stiffer than the belt 17, i.e. has a smaller percentage extent if subjected to the same tensile force. As the weight of the objects 5 resting on the belt 17 is transferred to the supporting belt 12, the belt 17 can have a lesser thickness than the supporting belt 12.

Various types of commercially available belt are suitable for constituting the belt 17 and the supporting belt 12. Merely by way of example, the supporting belt 12 can have a tensile core consisting of mixed aramid and polyester cloth and a permissible tensile force per millimetre of belt width equal to 80 N/mm to obtain a 1% elongation of the total extent of the belt starting from the slack belt; the belt 17 can have a tensile core consisting of polyester cloth and a permissible tensile force per millimetre of belt width equal to 11 N/mm to obtain a 1 % elongation of the total extent of the belt starting from the slack belt. The belt 17 extends longitudinally through the entire arrangement of decorating machines 10 parallel to the advancing direction F, defining a substantially continuous advancing surface through the arrangement of decorating machines 10.

With reference to Figure 2, the belt 17 extends transversely to the advancing direction F by a width that is at least the same as the cross dimension of the decorating head 4. If the printing heads 4A, 4B, 4C are not all the same as one another, the extent cross dimension of the belt 17 is the greater extent cross dimension, i.e. that of the decorating head that extends most orthogonally to the advancing direction F in a plane containing the advancing direction F.

Still with reference to Figure 1, the belt 17 is closed in a loop and is provided with an upper branch 19 interposed between each conveying device 3 A, 3B, 3C and each printing head 4A, 4B, 4C, and is further provided with a lower branch 20 arranged below each conveying device 3A, 3B, 3C.

The lower branch 20 of the belt 17 can be supported by a plurality of freely rotatable rollers 24 arranged below the conveying devices 3A, 3B, and 3C.

The belt 17 is wrapped around an inlet roller 21 such that an inlet portion of the upper branch 19 protrudes outside the arrangement of decorating machines 10. This inlet portion defines an inlet region 8 of the decorating apparatus 1. The inlet roller 21, around which the belt 17 wraps, can be connected to an inlet motor N. Driving the motor N promotes sliding of the lower branch 20 of the belt 17 around the inlet roller 21 and limits the upper branch 19 of the belt 17 from elongating locally at the inlet region 8 through the effect of the pull on the belt 17 induced by the conveying device 3 A, nearest the inlet region 8. The presence of the motor N does not affect the advancement of the belt 17, which is dragged by the various conveying devices 3 A, 3B, 3C.

The belt 17 is further wrapped around an exit roller 25, such that an exit portion of the upper branch 19 projects outside the arrangement of decorating machines 10, this exit portion defining an exit region 9 of the decorating apparatus 1. The exit roller 25, around which the belt 17 wraps, can be connected to an exit motor G, the drive of which promotes the sliding of the upper branch 19 of the belt 17 and the corresponding wrapping around the exit roller 25, preventing the belt 17 from being able to get wrinkled because of the reduction on the local tension of the belt 17 at the exit region 9. The presence of the exit motor G does not affect the advancement of the belt 17, which is dragged by the various conveying devices 3A, 3B, 3C. The inlet motors N and outlet motors G can be provided with the respective reduction gears or alternatively can be gear motors.

Each decorating machine 4 is provided with a control unit, not shown, in turn controlled by a central control unit, which is also not shown, by means of which the inlet motors N and outlet motors G, if present, are driven at the same speed as the motors M of the conveying devices 3A, 3B, 3C.

The decorating apparatus 1 can further comprise a cleaning device 29 arranged for cleaning the auxiliary advancing element 16. The cleaning device 29 comprises a washing tank 30 that is suitable for containing a washing fluid D, for example water. The cleaning device 29 further comprises a distributor 32 provided with a plurality of nozzles that are suitable for spraying the washing fluid D against the belt 17, in particular against the outer surface of the belt 17. A pump, which is not shown, removes the washing fluid D and delivers the washing fluid D via conduits, which are also not shown, to the distributor 32. The cleaning device 29 further comprises a doctor blade 31 , arranged above the washing tank 30 in contact with the belt 17 to remove an excess of the washing fluid D that can adhere to the belt 17 exiting the cleaning device 29. The doctor blade 31, placed in contact with the outer surface of the belt 17, further enables residues of ink or decorating material to be removed from the belt 17. The cleaning device 29 is arranged near the exit region 9 of the decorating apparatus 1. The washing tank 30 is located below the exit roller 25. In the inlet region 8, or in the printing machine 2A nearer the inlet region 8, there is a detecting device 23, by means of which the central control unit is alerted to the presence of each object 5 entering the decorating apparatus 1.

The auxiliary advancing element 16, and thus also the object 5 positioned thereupon, is driven by the conveying devices 3 to move continuously along the advancing direction F at the same speed as the conveying devices 3. The space travelled by the object 5 along the advancing direction F is determined on the basis of an encoder, which is not shown, which is also connected to the central control unit that measures the length travelled by the auxiliary advancing element 16. The various printing machines 4A, 4B, 4C are driven in a coordinated manner on the basis of a phase relation with the position of the auxiliary advancing element 16 and, thus, with the position of the object 5 along the advancing direction F. Since the inlet position of the object 5 is known as it is detected by the detecting device 23, the central control unit controls the printing heads 4A, 4B, 4C on the basis of the length of the route travelled by the object 5 during advancement, a measurement of this length being obtained by the encoder. In this manner, each printing head 4A, 4B, 4C starts to apply a decoration to the object 5 when the latter is positioned correctly with respect to the relative printing head 4A, 4B, and 4C.

As the object 5 rests on the auxiliary advancing element 16 which in turn is supported by each conveying device 3, the object 5 maintains a constant position compared with the conveying plane. In fact, the weight of the object 5 is transferred to the conveying device 3 and the auxiliary advancing element 16 does not suffer deformation because of the mass of the conveyed objects 5. This enables decorative layers to be obtained that are applied by the various decorating machines 2 that are centred between one another on the surface of the object 5 or are positioned between themselves with staggering that falls within the permissible tolerance.

The detecting device 23 is of known type and can comprise a photocell, or a plurality of photocells, or one or more cameras or a combination of photocells and cameras. This depends on the arrangement of the objects 5 on the auxiliary advancing element 16, if arranged in a single row or if arranged in several rows, as are the objects exiting the printing machine 2A in Figure 2, and, in this latter case, if the objects of the plurality of rows have a common front, i.e. front surfaces that are aligned on one another, or if the respective front surfaces are staggered in relation to one another along the advancing direction F.

The objects 5 to be decorated enter the decorating apparatus 1 from the inlet region 8, the resting surface 33 of the objects 5 being arranged above the auxiliary advancing element 16. The latter is driven in rotation around the inlet roller 21 and the exit roller 25 by the respective conveying devices 3A, 3B, 3C, which proceed substantially at the same speed. Reaching below the respective printing head 4 A, 4B, 4C, the objects 5 receive a respective layer of ink according to a predefined decorative layer. By proceeding along the advancing direction F, the objects 5 are decorated by the various decorating machines without stopping and exit the decorating apparatus through the exit region 9 bearing the image obtained from the superimposing of the decorative layers.

With respect to known decorating apparatuses, the auxiliary advancing element 16 enables the objects not to suffer substantial variations of position or slowing down in transit between one conveying device and the next one, in addition to ensuring constant motion with the variation of the load present thereupon, due to the mass of the objects. This enables particularly accurate prints to be obtained in which the centring tolerance between one decorative layer applied by a first printing machine and a further decorative layer applied by a further printing machine that is subsequent to the first is of the order of a few hundredths of a millimetre.

Also semifinished products having dimensions that are comparable to the distance between the printing machines 2A, 2B, 2C, or in general between two decorating machines of the arrangement 10, can be decorated with extreme precision with the decorating apparatus 1, limiting or even eliminating potential defects arising from the motion.

The auxiliary advancing element 16 further enables the conveying devices 3 A, 3B, and 3C to be maintained clean.

As it is the auxiliary advancing element 16 and not the conveying devices 3 A, 3B, 3C that collect possible ink that has escaped from the printing heads, it is possible to use a single cleaning device for all the printing machines 2A, 2B, 2C, or in general for all decorating machines of the arrangement 10. By cleaning a portion of the auxiliary advancing element 16 with the washing fluid D and using the doctor blade 31 inside the washing device 29, possible deposits of ink collected by the auxiliary advancing element 16 are removed from the surface of the latter, which restingly receives the objects 5.

The belt 17 in combination with the conveying devices 3 A, 3B, 3C enables a continuous conveying surface to be obtained that, being supported by the conveying devices 3A, 3B, 3C, is sufficiently stiff as not to suffer substantial longitudinal deformation on the basis of the weight of the conveyed objects 5, in particular in the transition zones between the various conveying devices 3A, 3B, 3C. This stiffness of the continuous conveying surface would not on the other hand be obtainable if the various conveying devices were replaced by a single belt conveyor. In this case, in fact, as the belt conveyor can be a tens of metres long, the corresponding belt would suffer not insignificant longitudinal stress in various sections of the belt conveyor, this deformation being the cause of sliding of the objects conveyed along the advancing direction and thus the origin of decorative layers that are not centred on one another.

Claims

1. Decorating apparatus for decorating objects (5), in the form of slabs or bars, comprising an arrangement of decorating machines (10) including one or more decorating machines (2A, 2B, 2C), each decorating machine (2A, 2B, 2C ) being provided with a decorating head (4A, 4B, 4C) and a conveying device (3 A, 3B, 3C) including support surface means (11) suitable for supporting and conveying said objects (5) to be decorated below said decorating head (4) along an advancing direction (F), characterized in that it further comprises an auxiliary advancing element (16) suitable for receiving and supporting said objects (5) to be decorated, said auxiliary advancing element (16) being draggable by said support surface means (11) along said advancement direction (F) through said arrangement of decorating machines (10).

2. Decorating apparatus (1) according to claim 1, wherein said auxiliary advancing element (16) comprises a belt (17) provided with a dragging surface (18) cooperating by friction with said support surface means (11) so that said belt (17) is actuated along said advancement direction (F) by said conveyor device (3 A, 3B, 3C) in each decorating machine (2A, 2B, 2C).

3. Decorating apparatus (1) according to claim 2, wherein said belt (17) extends longitudinally through the entire arrangement of decorating machines (10) parallel to said advancement direction (F), said belt (17) defining an advancing surface substantially continuous through said arrangement of decorating machines (10).

4. Decorating apparatus (1) according to claim 2 or 3, wherein said belt (17) extends transversely to said advancing direction (F) of a width at least equal to the size of a decorating head (4) of said arrangement of decorating machines (10), said size being measured orthogonally to said advancement direction (F) in a plane containing said advancement direction (F).

5. Decorating apparatus (1) according to any one of claims 2 to 4, wherein said belt (17) is closed in a loop and is provided with an upper branch (19) interposed between each conveying device (3A, 3B, 3C) and each decorating head (4A, 4B, 4C), and is further provided with a lower branch (20) arranged below each conveyor device (3 A, 3B, 3C) of said arrangement of printing machines (10).

6. Decorating apparatus (1) according to claim 5, wherein said belt (17) is wrapped around an inlet roller (21) so that an inlet portion of said upper branch (1 ) projects outside said arrangement of decorating machines (10), said inlet portion defining an inlet region (8) of said decorating apparatus (1).

7. Decorating apparatus (1) according to claim 6, wherein said belt (17) is wrapped around an exit roller (25) so that an exit portion of said upper branch (19) projects outside said arrangement of decorating machines (10), said exit portion defining an exit region (9) of said decorating apparatus (1).

8. Decorating apparatus (1) according to any one of claims 1 to 7, and further comprising a cleaning device (29) arranged to clean said auxiliary advancing element (16).

9. Decorating apparatus (1) according to claim 8, wherein said cleaning device (29) comprises a washing tank (30) suitable for containing a washing fluid (D) and to receive at least a portion of said auxiliary advancing element (16) for cleaning said portion with said washing fluid (D).

10. Decorating apparatus (1) according to claim 9, wherein said cleaning device (29) further comprises a doctor blade (31), arranged to contact said portion of said auxiliary advancing element (16) to remove from said portion an excess of said washing fluid (D).

11. Decorating apparatus (1) according to claim 10 as claim 8 is appended to any one of claims 2 to 7, wherein said portion comprises an area of an outer surface of said belt (17).

12. Decorating apparatus (1) according to any one of claims 8 to 11 as claim 8 is appended to claim 7, wherein said cleaning device (29) is arranged nearer to said exit region (9) of said decorating apparatus (1).

13. Decorating apparatus (1) according to any one of claims 2 to 12, wherein said dragging surface (18) and/or said support surface means (11) consists of polymeric material comprising polyurethane.

14. Decorating apparatus (1) according to claim 6, or 7, wherein said inlet roller (21) is connected to an inlet motor (N).

15. Decorating apparatus (1) according to claim 7, or according to claim 14 as appended to claim 7, wherein said exit roller (25) is connected to an exit motor (G).

16. Decorating apparatus (1) according to any preceding claim, wherein said conveyor device (3A, 3B, 3C) is selected from a group comprising: a belt conveyor, a roller conveyor.