Substrate printing system

Abstract

A substrate printing system is disclosed having a perforated conveyor belt adapted for transporting on the same a substrate to be printed, wherein the perforated conveyor belt has a set of perforations; a perforated grill which has a set of perforations and which is configured such that the perforated conveyor belt can be moved over the perforated grill; and a suction chamber which has a suction element, the suction chamber being in communication with the perforated conveyor belt and with the perforated grill such that the suction flow created by the suction element is adapted for passing through perforations of the perforated conveyor belt and of the perforated grill to secure the substrate to the perforated conveyor belt.

Claims

1. A substrate printing system, comprising: a perforated conveyor belt adapted for transporting a substrate to be printed, wherein the perforated conveyor belt comprises a set of perforations, a perforated grill which comprises a set of perforations and which is configured such that the perforated conveyor belt can be moved over the perforated grill, and a suction chamber in communication with the perforated conveyor belt and with the perforated grill such that a suction flow created by the suction chamber is adapted for passing through perforations of the perforated conveyor belt and of the perforated grill to secure the substrate to the perforated conveyor belt, wherein: the perforations of the perforated grill have a different pattern in a first area adapted for printing substrates than in a second area not adapted for printing substrates; the perforations of the perforated grill are configured to produce greater blocking of the suction flow through said perforations in the first area adapted for printing substrates than in the second area not adapted for printing substrates; and the perforated grill is removable in the first area adapted for printing substrates with respect to the second area not adapted for printing substrates; wherein the substrate printing system further comprises: a blocking means adapted to at least partially block the suction flow through perforations to a different extent in the first area adapted for printing substrates than in the second area not adapted for printing substrates.

2. The substrate printing system according to claim 1, wherein the blocking means comprise blocking valves or inserts of the perforations in the area adapted for printing substrates.

3. The substrate printing system according to claim 1, wherein the blocking means comprise a laminar blocking element which is arranged parallel to the perforated conveyor belt in the area adapted for printing substrates.

4. The substrate printing system according to claim 3, wherein the laminar blocking element is provided with a set of perforations.

5. The substrate printing system according to claim 4, wherein the set of perforations of the laminar blocking element are configured to produce greater blocking of the suction flow through the set of perforations in the area adapted for printing substrates than in the area not adapted for printing substrates.

6. The substrate printing system according to claim 3, wherein a permeable strip is disposed in at least one area of the laminar blocking element without perforations, wherein the laminar blocking element is permeable to the suction flow in the at least one area.

7. The substrate printing system according to claim 3, wherein the laminar blocking element is fixed on the perforated grill in contact with the same.

8. The substrate printing system according to claim 3, wherein the laminar blocking element is arranged stationary on the perforated conveyor belt between substrate and perforated conveyor belt.

9. The substrate printing system according to claim 1, wherein the blocking means are removable with respect to the perforated conveyor belt and/or the perforated grill.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) In order to complete the description and with the aim of providing a better understanding of the invention, some figures are provided. Said figures form an integral part of the description and illustrate an exemplary embodiment of the invention.

(2) FIG. 1 shows a transversal schematic view of a printing machine of the type to which the invention is applied.

(3) FIG. 2 shows a schematic plan view of three exemplary embodiments for supplying a substrate on a perforated conveyor belt.

(4) FIG. 3 shows a lateral schematic section to the perforated conveyor belt, of the perforated grill and to the suction chamber of an exemplary embodiment of the invention.

(5) FIGS. 4a, 4b show a schematic plan view of the perforated grill according to respective embodiments according to the invention.

(6) FIG. 5 shows a schematic plan view of the conveyor belt on which a laminar blocking element is arranged between a substrate to be printed and the conveyor belt according to an embodiment of the invention.

(7) FIG. 6 shows different embodiments of laminar blocking elements according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

(8) An exemplary embodiment of a printing machine according to the invention is represented in FIG. 1, comprising: The perforated conveyor belt (1) which is mobile and transports on the same the substrate (5) to be printed. Accordingly, the perforated conveyor belt (1) is represented in FIGS. 2 and 5, comprising a set of perforations (10). The perforated grill (2) which is static and which, in the exemplary embodiment, is also metal. The perforated conveyor belt (1) is moved over said perforated grill (2). The perforated grill (2) comprises a set of perforations (20). The suction chamber (3), represented in FIG. 1, comprises a suction element (not represented) which creates a suction flow which passes through the perforations (10, 20) of the perforated conveyor belt (1) and of the perforated grill (2) to secure the substrate (5) to the perforated conveyor belt (1).

(9) The solution of the state of the art relating to the vertical lateral plates (6) of the suction chamber is also represented in FIG. 1 which may be adjustable in width by means of moving the same (6). Using these lateral plates (6), the perforations (20) of the laterals of the perforated grill (2) can be disabled, to a greater or lesser extent, thus leaving open the perforations (20) which correspond to the measurement in width of the substrate (5) to be printed.

(10) In the exemplary embodiment according to the invention corresponding to FIG. 3, an area (21) is shown adapted for printing and an area (22) not adapted for printing. In the area (21) adapted for printing, the printing heads (11) are arranged over the conveyor belt (1) for printing the substrates (5) while they advance with the movement of the conveyor belt (1) below the printing heads (11). The different areas (21) adapted for printing can be for printing different colours. According to the embodiment shown, both in the printing area (21) and in the area (22) where there is no printing, the securing of the substrates (5) is caused by the suction air flow which passes through the conveyor belt (1) and the perforated grill (2) when being suctioned by the suction elements of the suction chambers (3).

(11) The perforated grill (2) shown in the embodiment of FIG. 3 is removable (4) in each one of the two suction areas (21) according to the embodiment, allowing it, for example, to be removed and substituted with other perforated grills (2) for the cleaning, repair or maintenance thereof and access to the suction chambers (3) once removed.

(12) In FIGS. 4a and 4b, embodiments are shown of the perforated sheet (2) according to the invention wherein the perforations (20) in the printing area (21) have a pattern different from the perforations (20) in the area (22) where there is no printing, in this case to produce greater blocking (fewer number of holes which can be open to the passage of the suction air flow) in the printing area (21) than in the area (22) where there is no printing. The difference between both embodiments of FIGS. 4a and 4b is that in the embodiment of FIG. 4b, the blocking is caused by means of blocking valves or inserts (8) arranged in the perforations shown for completely blocking each one of said perforations (20). The perforated grill (2) is preferably removable in the printing areas (21).

(13) The perforated conveyor belt (1) is moved on the optionally removable perforated grill (2), leaving some of the perforations (10) of the perforated conveyor belt (1) blocked by the perforated grill (2) itself. In this way, the perforations (10) of the perforated conveyor belt (1) which are not adapted for being covered by the substrate (5) are blocked at least partially by the perforated grill (2).

(14) One of the advantages of implementing removable (4) perforated metal grills (2) is that the cleaning thereof is facilitated and at the same time it also facilitates the cleaning of the housing thereof in the printing areas (21). To this end, the perforated grill (2) can be removably fixed, in particular screwed or similar or simply supported or superimposed on the suction chamber (3). When the removable perforated grills (2) are removed, disassembling them from the upper part of their support structure in the manner of a drawer of the suction chamber (3), access to the suction chamber (3) is also enabled for its cleaning.

(15) To achieve a maximum reduction of the perforations (10) of the perforated conveyor belt (1) which are uncovered, the distribution pattern of the perforations (20) of the removable perforated grill (2) can be contemplated as a function of the different substrates (5) to be printed, in particular of the measurements and features of the substrate (5) to be printed and how the substrates (5) are going to be placed on the perforated conveyor belt (1).

(16) In another exemplary embodiment, the blocking means can be formed by a laminar blocking element (7) parallel to the perforated conveyor belt (1) which is located on the perforated grill (2) and therefore below the perforated conveyor belt (1) in the printing area (21).

(17) Specifically, in this embodiment, the laminar blocking element (7) comprises an additional perforated grill with a set of perforations different from the distribution pattern of the perforated grill (2) in an area (22) where there is no printing, the additional perforated grill (4) being located between the perforated grill (2) and the perforated conveyor belt (1). More specifically, the perforated grill (2) comprises a housing with a determined thickness, for inserting the additional perforated grill. The additional perforated grill (4) will preferably be metal and easy to remove.

(18) The additional perforated grill comprises a perforation distribution pattern which differs from the distribution pattern of the perforations (20) of the perforated grill (2), such that perforations (10) of the perforated conveyor belt (1) which are not adapted for being covered by the substrate (5) are blocked at least partially by the additional perforated grill, preventing or at least minimising the previously indicated problems.

(19) The perforations of the additional perforated grills can be implemented as a function of: The measurements and features of the substrate (5) to be printed. How the substrates (5) are going to be placed on the perforated conveyor belt (1).

(20) It has also been anticipated that different sets of additional perforated grills can be provided. In this way, either are selected as a function of the features of the laminar substrate (5) and how they are going to be placed on the perforated conveyor belt (1).

(21) As mentioned for the previous exemplary embodiment, the removable condition of these additional perforated grills facilitates their cleaning, removing them from their housings in the perforated grill (2) and thus being taken to a cleaning point.

(22) Another exemplary embodiment is represented in FIG. 5 in which the blocking means are formed by a laminar blocking element (7) parallel to the perforated conveyor belt (1) which travels on the conveyor belt (1) and below the substrate (5). When the laminar blocking element (7) arrives to the printing area (21) with the substrate (5) arranged on the laminar blocking element (7), the blocking of the perforations (10) of the conveyor belt (1) is caused in the printing area (21) with respect to the area (22) where there is no printing.

(23) Two embodiments of laminar blocking elements (7) are shown in FIG. 6 configured for being arranged on the conveyor belt (1). In the embodiment on the left, the laminar blocking element presents a set of perforations (30) with a determined pattern on its entire surface. In the embodiment on the right, the laminar blocking element presents a border area without perforations such that in said area the perforations (10) of the conveyor belt (1) are completely blocked, preventing the printing problems of the suction air flow in said border area.

(24) An exemplary embodiment is also envisaged consisting of a permeable strip, for example porous, to the suction flow in an area of the laminar blocking element (7) without perforations (30). In this way, the laminar element allows the passage of suction flow in said permeable area, but reducing the turbulences created by said flow.

(25) It is envisaged that the laminar blocking element (7) can be disposable such that it could be introduced with the substrate (5) on the perforated conveyor belt (1) and removed with the printed substrate (5) at the end of the process. One problem is that as the strip (7) would travel below the substrate (5) for the entire route of the perforated conveyor belt (1), the vacuum would reduce on its entire journey, not only in the printing area. However, it has the advantage of being able to adapt the suction to the type of substrate (5), a type of strip or pattern being selected for each substrate (5).

(26) The following possible exemplary embodiments are envisaged: Replacing the entire welded upper grill of the suction cavity in the printing area with an upper sheet grill with removable fixing, such as for example screwing. Recess or housing in the welded upper grill to insert in the same an additional perforated grill in the recess. Superimposing the additional perforated grill on the conventional welded upper grill. Strip which travels on the conveyor belt (1) between the substrates and the conveyor belt (1).