ES2563128B2 - Conveyor module for laminar bodies in a flexographic printer and flexographic printer - Google Patents

Abstract

Conveyor module of laminar bodies in a flexographic printer comprising rotating cliché-bearing cylinders linked to the ink supply, the rotating cylinder being provided to contact the lower face of the laminar body, said conveyor module (4) comprising a drawer (6) formed by an upper cover, side walls and a lower open base, inside which there is a rotating counter-printing cylinder (7) that rotates in a forward direction and positioned relative to a rotating cylinder of the flexographic printer, intended for contact a conveyor belt (8) perforated with holes, whose underside of the conveyor belt (8) has the laminar body. In addition, it comprises an air intake duct having an end in communication with the inside of the drawer (6), such that in an operative condition a vacuum effect is generated leaving the laminar bodies adhered to the conveyor belt (8); and a perforated plate located near the open base of the drawer (6), provided with holes that allow a suction effect on the laminar body.

Description

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DESCRIPTION

Conveyor module of laminar bodies in a flexographic printer and flexographic printer

OBJECT OF THE INVENTION

The purpose of this application is to register a conveyor module intended to transport or move laminar bodies through a flexographic printer.

More specifically, the invention proposes the development of a laminar body conveyor module in a flexographic printer as well as a flexographic printer provided with at least one module according to revindication 1.

BACKGROUND OF THE INVENTION

Current flexographic printing machines with high print quality tend to have a configuration with separate printing bodies, which entails a series of advantages such as being able to couple dryers (either hot air, infrared rays or ultraviolet rays) with the purpose of drying the newly printed color before printing the next color. Another advantage that derives is that it allows, with the machine in operation and in production, the clicks can be changed and the printing groups that are not printing at that time can be cleaned, which results in an increase in productivity. On the contrary, in compact machines where the printing groups are very close to each other, the machine must be stopped and separated to perform the operations of replacing the click, cleaning or maintenance, so that production has to be interrupted.

Traditionally, transport between printing groups of panchas of sheet material,

as for example, corrugated cardboard sheets for the formation of boxes, it has been made

by several pairs of rollers that drag the plates. In order not to harm the

impression during said drag, the rollers in contact with the printed face, instead of

They are cylinders that occupy the width of the machine, they are usually narrow movable rings

on an axis which are fixed to this in a certain position so that they are not in

contact with newly printed areas. This operation requires time and operations.

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Experienced and prepared. In addition, in the case of flexible materials, such as corrugated cardboard, said drag rings can produce completely unwanted grooves in the plates, especially if a good adjustment of the pressure exerted on said plates is not made.

Various systems based on aspiration have been developed in order to avoid maximum contact of the printed side of the plate with any element other than the click of the printing cylinder itself. One of these systems based on aspiration is through the use of rollers that occupy the width of the machine with suction means between them, however, it is not recommended because it requires a high air flow and is very noisy due to the loss of air that takes place during operation. In addition, with this system, the front part of the box "stumbles" on each of the rollers, so that there are small delays during transport that can cause a defective impression. In the prior art, drawers with suction transport equipped with rollers of smaller dimensions arranged to three-roll so that the front edge of the laminar body is on a more regular surface, thus minimizing the previous problem, although in practice it He has observed that the front edge of the laminar body continues to hit the rollers.

All systems based on trailed rollers or suction drawers with rollers have the main drawback associated with roller wear that results in a decrease in the drag capacity of the laminar bodies, causing unwanted sliding between the laminar body (or also called plate) and rotating rollers as well as a reduction in transport speed due to the reduction in the ratio between them. This fact not only affects a bad registration between colors to be printed on the sheet body but can also cause a defective impression because the transport speed is lower than the tangential speed of the printing cylinder.

On the other hand, it is also known in the state of the art systems based on suction belts which have a high maintenance cost and a complex maintenance to carry out so that they imply a longer downtime during maintenance operations.

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In addition, the applicant is not currently aware of an invention that has all the features described herein.

DESCRIPTION OF THE INVENTION

The present invention has been developed in order to provide a conveyor module that is configured as a novelty within the field of application and resolves the aforementioned drawbacks, also providing other additional advantages that will be apparent from the accompanying description. then

It is therefore an object of the present invention to provide a laminar body conveyor module in a flexographic printer, in which the flexographic printer comprises at least one rotating click-through cylinder linked to ink supply means or similar printing material, the rotating cylinder being provided to come into contact with the lower face of the laminar body to be printed.

More particularly, the invention is characterized by the fact that said conveyor module comprises:

- a drawer formed by an upper cover, side walls and a lower open base, inside which there is a rotating counter-printing cylinder that rotates in a forward direction and positioned in relation to a rotating cylinder of the flexographic printer, intended for being in contact with a conveyor belt that is perforated with multiple through holes present along its entire length arranged in the form of a closed loop, in which the lower face of the conveyor belt is intended to come into contact with the laminar body , the conveyor belt being driven in motion by drive means;

- an air suction duct in which one of its ends is in communication with the inside of the drawer while the opposite end of the duct is linked to air suction means, such that an aspiration effect is generated in an operational condition in which a laminar body is adhered to the underside of the conveyor belt; Y

- a perforated plate located near the open base of the drawer provided with a plurality of through holes such that it is intended to contact the laminar body to move during operation of the suction means.

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Thanks to these characteristics, a system for the transport of laminar bodies is obtained, such as templates to form cardboard boxes, of simple fabrication that guarantees the correct application and adhesion of the ink on one of the faces (in this case, the face lower of the laminar body) in the absence of "jumps" or irregularities (formation of undulations along the laminar body) between each cylinder that is provided with ink from a flexographic printer.

In this report, the conveyor belt is understood as the one consisting of a single body or multiple parts joined or linked together.

Particular and advantageous features of the present invention are described in the dependent claims.

According to an advantageous aspect of the invention, the module may include a dynamic tensioner arranged at a point along the conveyor belt. In this way, a constant and adequate tension value is maintained in the conveyor belt regardless of the creep elongation due to its utilization and printing defects on the laminar body to be transported and printed are avoided. It should be taken into account that although the band is made of a material with high rigidity, it is inevitable that a gradual extension of the same will occur during its application in flexographic printers during its passage through the aspirated branch.

Preferably, the drawer includes a series of mobile lower supports that are capable of coming into contact with the lower face of the laminar body that will support the conveyor belt when the aspiration operation is not activated. In this way, it is avoided that the buckling of the conveyor belt when there is no aspiration causes it to be placed on the click holder cylinder, which is not convenient because it stains ink accumulated on the surface of the click holder or even , could adhere to it unwantedly.

According to another aspect of the invention, it includes an additional aspiration chamber located inside the central chamber, said additional aspiration chamber being linked to an additional aspiration duct. In this way, the laminar element is prevented from sticking to the click, especially when working with laminar bodies with low rigidity

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as cardboard sheets, since in the case of detecting this circumstance this additional suction chamber will be activated.

Other features and advantages of the conveyor module object of the present invention will be apparent from the description of a preferred, but not exclusive, embodiment illustrated by way of non-limiting example in the accompanying drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1.- It is a perspective view of three conveyor modules according to the invention that are linked together in series;

Figure 1a.- It is a detail view of a part of Figure 1;

Figure 2.- It is a schematic elevation view of Figure 1;

Figure 3.- It is a plan view where the distribution of the different interior chambers housed in the drawer of the conveyor module is appreciated; Y

Figure 4.- It is a perspective view of a conveyor module according to the present invention partially sectioned to facilitate visualization of the internal components.

DESCRIPTION OF A PREFERRED EMBODIMENT

In view of the aforementioned figures and, according to the numbering adopted, an example of a preferred embodiment of the invention can be observed therein, which comprises the parts and elements that are indicated and described in detail below.

A flexographic printer for printing corrugated cardboard bodies (1) for the formation of boxes, in which it comprises a plurality of rotating click-through cylinders (2) linked to a respective color, arranged in FIG. in series (in this case three rotating cylinders) that rotate in the direction of advance of the laminar body, indicated by the arrow (f), each of them linked to ink supply means (not shown) through a pair of additional cylinders (3). Each of the rotating click-through cylinders (2) is associated superiorly to a conveyor module, generally indicated by reference (4), which is detailed below.

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Between each of the modules a drying device (5) of known type may be available, so that it is not going to go into greater detail in its description, (represented schematically in Figure 2) carried out by the drying of the ink printed on the underside of the laminar body (1) after having previously passed through a corresponding cylinder provided on its surface with a certain ink, that is, it is sandwiched between two conveyor modules (4).

This conveyor module (4) comprises a drawer (6) formed by an upper cover, side walls and a lower open base, inside which a rotating counter-printing cylinder (7) is housed that rotates in a forward direction and positioned with in relation to a rotating cylinder of the flexographic printer, intended to be in contact with a conveyor belt (8) that is perforated with multiple through holes present along its entire length arranged in the form of a closed loop, in which the face The lower part of the conveyor belt (8) is intended to come into contact with the laminar body (1). The conveyor belt is driven in motion by drive means (not shown), such as, for example, motor means operable by a push button. The module (4) also comprises an air suction duct (11) that is one of its ends in communication with the inside of the drawer (6) while the opposite end of the duct is linked to air suction means, such that in an operational condition a vacuum effect is generated in which a laminar body (1) is adhered to the lower face of the conveyor belt (8).

With particular reference now to the aforementioned drive means, they comprise a conductive cylinder (9) on which the conveyor belt capable of rotating by the action of motor means that are linked to the driver cylinder (9) and a series of rollers slides. of guide or pulleys (10) on which the conveyor belt (8) slides.

As can be seen in Figure 4, there is also provided a perforated plate (12) arranged in a horizontal plane that is located near the bottom flange of the open base of the drawer (6), provided with a plurality of through holes such that it is provided to contact the laminar body (1) to move during operation of the suction means.

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Advantageously, a dynamic tensioner (13) provided at a point along the conveyor belt (8), in this case a conductive cylinder (9), is provided near the cylinder that has been schematically represented in Figure 2 .

As can also be seen more clearly in Figures 3 and Figure 4, inside the drawer (6) there are a plurality of separation walls (14) arranged transversely with respect to the rotating counter-printing cylinder (7), such that a central chamber (15), two lateral chambers (16) and two extreme chambers (17) arranged on opposite sides of the drawer are defined, each of the end chambers (17) being linked to a secondary aspiration duct (24). Each separation wall (14) has in its central part a recessed region (140) of curved contour through which the rotating counter-printing cylinder (7) passes, whereby it adapts to the contour and diameter of the counter- rotary printer (7).

Each module (4) may include an additional aspiration chamber (18) located inside the central chamber (15) of the drawer (6), said additional aspiration chamber (18) being linked to an additional aspiration conduit (19). ) of smaller dimensions than the air intake duct that acts on the central chamber (15). As can be seen, the additional suction chamber (18) is located next to the rotating counter-printing cylinder (7), and more specifically after the rotating counter-printing cylinder (7) in the direction of advance of the laminar body (1).

Additionally, the drawer (6) includes a series of movable lower supports (20) capable of coming into contact with the lower face of the laminar body (1), which may have an automated mechanism (not shown) that acts as synchronized form with the aspiration means. As can be seen, each of the lower movable supports (20) comprises a cylinder or roller (21) that is supported at each of its ends by a fastener (22) that is pivotally mounted in the drawer (6 ) with an axis of rotation (23).

The details, shapes, dimensions and other accessory elements used in the manufacture of the conveyor module of the invention may be conveniently substituted by others that do not depart from the scope defined by the claims included below.

Claims (9)

5 10 fifteen twenty 25 30 35 1. Conveyor module for laminar bodies in a flexographic printer, in which the flexographic printer comprises at least one rotating click-through cylinder linked to means for supplying ink or similar printing material, the rotating cylinder being provided for contact with the lower face of the laminar body to be printed, characterized in that said conveyor module (4) comprises: a drawer (6) formed by an upper cover, side walls and a lower open base, inside which a rotating counter-printing cylinder (7) is housed that rotates in a forward and positioned direction relative to a rotating cylinder of the flexographic printer, intended to be in contact with a conveyor belt (8) that is perforated with multiple through holes present along its entire length arranged in the form of a closed loop, in which the underside of the conveyor belt (8 ) is intended to come into contact with the sheet body, the conveyor belt being driven in motion by drive means; an air suction duct that is one of its ends in communication with the inside of the drawer (6) while the opposite end of the duct is linked to air suction means, such that an aspiration effect is generated in an operational condition in which a laminar body is adhered to the underside of the conveyor belt (8); Y a perforated plate that is located near the open base of the drawer (6), being provided with a plurality of through holes such that the perforated plate is intended to contact the laminar body to move during operation of the suction means. 2. Conveyor module according to claim 1, characterized in that it includes a dynamic tensioner (13) disposed at a point along the conveyor belt (8). 3. Conveyor module according to revindication 1, characterized in that a plurality of separation walls arranged transversely with respect to the rotating counter-printing cylinder (7) is arranged inside the drawer, such that at least one central chamber is defined (15) and two end chambers arranged on opposite sides of the drawer (6), each of the end chambers being linked to a secondary suction duct. 5 10 fifteen twenty 25 4. Conveyor module according to claim 3, characterized in that each separation wall has a recessed region through which the rotating counter-printing cylinder (7) passes. 5. Conveyor module according to claim 3, characterized in that it includes an additional aspiration chamber located inside the central chamber (15), said additional aspiration chamber (18) being linked to an additional aspiration duct ( 19). 6. Conveyor module according to claim 1, characterized in that the drawer includes at least one lower mobile support (20) capable of coming into contact with the lower face of the conveyor belt (8). 7. Conveyor module according to claim 6, characterized in that the mobile lower support (20) comprises a cylinder that is supported at each of its ends by a fastening element that is pivotally mounted in the drawer (6 ). 8. Conveyor module according to claim 1, characterized in that the drive means comprise at least one conductive cylinder on which the conveyor belt (8) slides capable of rotating by the action of motor means that are linked to the conductive cylinder and at least one guide roller on which the conveyor belt (8) slides. 9. Flexographic printer for laminar body printing, in which it comprises a plurality of rotating cylinders arranged in series that rotate in the direction of advance of the laminar body, each of them linked to ink supply means or similar printing material , characterized in that each of the rotating cylinders is associated superiorly to a conveyor module according to any one of claims 1 to 8.