A rotary decorating machine for ceramic tiles

Abstract

 The rotary decorating machine for ceramic tiles of the invention comprises: an impression cylinder (1); a transfer roller (3) acting in relative rotation in combination with the impression cylinder (1); a first roller (4) and a second roller (5), parallel one to another and provided with opposite motion directions, which in combination afford a funnel-shaped cavity into which glaze is fed. The second roller (5) is parallel to and in contact with the transfer roller (3) on a surface of which it rolls undraggingly. Above the funnel-shaped cavity a plurality of nozzles (6, 7 and 8) is arranged, each able independently to dispense a type of glaze in a batched dose.

Description

[0001] Prior-art rotary decorating machines for glaze-patterning tiles use a rotary printing cylinder on which the glaze is loaded and distributed by a transfer roller, predisposed to roll undraggingly on the impression cylinder. The glaze is predisposed on the transfer roller by a further roller rotating contactingly on said transfer roller. In all prior art realizations each machine works with one colour only, or more precisely with one type only of glaze, so that in order to obtain decorations containing more than one colour, several machines have to be predisposed according to the number of colours required for the finished decoration.

[0002] The present invention, as it is characterized in the claims that follow, provides a decorating machine capable of actuating a decoration procedure on ceramic tiles in which in a single operation a multi-coloured pattern can be achieved, which pattern is charactenzed by a special blurred effect.

[0003] The main advantages of the present invention are constituted by constructional simplicity and functionality.

[0004] Further characteristics and advantages of the present invention will better emerge from the detailed description that follows, of an embodiment of the invention, illustrated in the form of a non-limiting example in the accompanying drawings, in which:
figure 1 is a schematic perspective view of the invention.

[0005] With reference to the figure, 1 denotes an impression cylinder bearing, engraved into an external cylindrical surface thereof, decorations to be reproduced on ceramic tiles 2 fed to the cylinder by a transport line 12. The printing is achieved by rolling the impression cylinder 1 on the upper surface of the tiles 2. Glaze is deposited on the cylinder external surface by means of a transfer cylinder or roller 3 arranged parallel to the impression cylinder 1 and in contact therewith. A feed group continuously supplies the transfer roller 3 with a sufficient and homogeneous layer of glaze, which is then transferred during relative rolling from said transfer roller 3 to said impression cylinder 1.

[0006] The feed group comprises a first roller 4 and a second roller 5, reciprocally parallel and in reciprocal contact and rotating in different directions. The second roller 5 is also in contact with the transfer roller 3. The two rollers 4 and 5 together afford a funnel cavity above which three independent feed nozzles 6, 7 and 8 are distributed. The nozzles 6, 7 and 8 are aligned according to a direction which is parallel to the axes of the rollers 4 and 5. Each nozzle is predisposed to dispense a type of glaze in a batched quantity. Batcher devices are provided, denoted respectively by 9, 10 and 11, which on command dispense a precise quantity of glaze to the respective nozzles 6, 7 and 8.

[0007] A collection tray 13 is positioned below the rollers 4 and 5 and partially below the transfer roller 3, to prevent traces or drops of glaze from falling on the tiles 2 transiting along the transport line 12 before the tiles come into contact with (and are decorated by) the impression cylinder 1. During normal up-to-speed machine functioning, different glazes are conveyed through the nozzles 6, 7 and 8 into the cavity afforded by the upper external surfaces of the rollers 4 and 5.

[0008] The roller 4, rolling in an opposite direction to roller 5, has the task of distributing continuously on the surface of roller 5 a sufficiently uniform layer of glaze. When different glazes are dispensed from nozzles 6, 7 and 8 into said cavity, the roller 5 will be covered with a layer of glaze composed of three different colours. In the edge zones between the colours, that is for example where the glaze from nozzle 6 meets the glaze from nozzle 7, there will be a partial mixing of the colours.

[0009] A further step is achieved during rolling contact between the roller 5 and the transfer roller 3, where a greater uniformity is achieved in the thickness of the layer of glaze, without altering the composition of the layer itself, which is constituted by three distinct layers of colour.

[0010] The impression cylinder 1 then distributes the three colours on a tile (when the latter comes into contact with the former) as if they were a single layer of glaze.

[0011] Thus, with a single passage in a single decorating machine, a layer of glaze is deposited on a tile which layer is composed of a plurality of colours which number depends on the number of nozzles operating above the rollers 4 and 5. With known-type realizations, the depositing of three colours on a single tile requires three passages, that is three distinct decoration operations performed by three different decorating machines.

[0012] The invention is therefore especially useful for the production of ceramic tiles having a blurred colour effect.

[0013] In the embodiment described the nozzles 6, 7 and 8 are fixed, but embodiments could be realized in which they were mobile, able to be displaced at least in a parallel direction to the roller 4 and 5 axes during normal machine functioning.

[0014] A further embodiment, not illustrated in the figure, offers the possibility of effecting the deposit of the pluri-coloured layer of glaze on the transfer roller 3 by means of spray guns, predisposed to operate on the surface of the cylinder itself and appropriately distanced in a longitudinal direction.

[0015] In a further embodiment of the invention, a variation of colour tone on the tiles can be achieved also in the advancement direction thereof. To obtain this it will be sufficient to feed a single nozzle alternatingly with different glazes.

[0016] Also in this embodiment a process for rotary decoration of tiles is obtained, in which the following are used:

an impression cylinder 1 destined to come into rolling contact with ceramic tiles 2;

a transfer roller 3 for rollingly transferring a layer of glaze on an external surface of said impression cylinder 1, to which it is parallel;

means for depositing on said transfer roller 3 a layer of glaze, by means of which various different glazes are deposited on different zones of a same transfer roller 3.

Claims

1. A decorating machine for ceramic tiles, comprising:

an impression cylinder (1) ) destined to come into contact with tiles (2);

a transfer roller (3) for transferring by relative rolling a layer of glaze on an external surface of said impression cylinder (1), to which it is parallel;

means for depositing a layer of glaze on said transfer roller (3);

characterized in that said means are arranged such as to deposit layers of different glazes on different zones of said transfer roller (3).

2. A machine as in claim 1, characterized in that said means for depositing comprise:
   a first roller (4) and a second roller (5), parallel and in reciprocal contact, provided with opposite rotation directions, which together afford a funnel-shaped cavity predisposed to receive glazes; said second roller (5) being parallel to and in undragging contact with said transfer roller (3);
a plurality of independent feeding nozzles (6, 7 and 8) distributed along said funnel-shaped cavity in a parallel direction to axes of said first and second rollers (4 and 5); each of said nozzles (6, 7 and 8) being predisposed to dispense a distinct colour of glaze in batched doses.

3. A machine as in claim 1, characterized in that each of said nozzles (6, 7 and 8) is fed with a distinct glaze by means of a dedicated batching machine (9, 10 and 11).

4. A process for rotary decoration of ceramic tiles, using:

an impression cylinder (1) destined to come into rolling contact with ceramic tiles (2);

a transfer roller (3) for rollingly transferring a layer of glaze on an external surface of said impression cylinder (1), to which it is parallel;

means for depositing on said transfer roller (3) a layer of glaze;

characterized in that through said process various different glazes can be deposited on different zones of the same transfer roller (3).

Drawing