IL290673A

IL290673A - Apparatus for cleaning sheets of paper material

Info

Publication number: IL290673A
Application number: IL290673A
Authority: IL
Inventors: Petratto Giorgio
Original assignee: Petratto Giorgio
Priority date: 2021-02-19
Filing date: 2022-02-16
Publication date: 2022-09-01
Also published as: IT202100003830A1

Description

Apparatus for cleaning sheets of paper material Technical field The present invention pertains to the field of paper industry and refers to the cleaning of sheets of cardboard, paperboard, paper, and similar materials, coming out of a LASER cutting machine.

Background art Digital cutting and creasing machines using LASER technology are widespread for processing cardboard and paper sheets. The cuts and creases obtained with this technology make it possible to create paper products even having complex shapes, for example cardboard packaging or labels with internal cutouts. The LASER cutting technology is also used for cutting adhesive labels in rolls, where the edges of the labels are cut in the adhesive layer applied to a support layer of siliconized paper.

Sheets exiting a LASER cutting machine often have smears or small spots, and burn residues due to LASER radiation during cutting. Residues are in the form of very fine dust marks scattered on the surface of the sheet struck by LASER radiation, adjacent to the edges cut by the radiation.

Summary of the invention An object of the present invention is to provide an apparatus capable of effectively removing dust residues left by previous processing with LASER technology on the surfaces of sheets of cardboard, paper, and similar materials.

This object is achieved, according to an aspect of the present invention, by an apparatus for cleaning sheets having the features defined in claim 1. Preferred embodiments of the apparatus are defined in the dependent claims.

DynamicPDF for .NET v8.0.0.40 (Build 29393) Evaluating unlicensed DynamicPDF feature. Click here for details. [4:0:v8.0] 2 In summary, an apparatus for cleaning sheets of paper material, includes a motor driven feeding member for advancing a sheet in a given direction of advancement, the sheet having a face to be cleaned facing away from the motor driven feeding member. A fibrous strip, opposed to the motor driven feeding member, cleans the face of a sheet in transit on said motor driven feeding member by wiping it. A pressing device urges the fibrous strip towards the motor driven feeding member and against the face of the sheet to be cleaned in transit on the motor driven feeding member, determining a transversely elongated contact area between the sheet and the fibrous strip. A humidifying device humidifies the fibrous strip or the upper faces of the sheets in transit, in such a way that the face of the sheet contacted by the wet fibrous strip is cleaned by wiping, with consequent removal of residues from previous cutting and / or creasing operations carried out by a LASER technology processing machine.

According to another aspect, the present invention provides a machine for processing sheets with LASER technology, in particular a cutting machine, comprising a cleaning apparatus as defined in the appended claims.

According to a further aspect, the present invention relates to the combination of an apparatus, as defined in the appended claims, with any one of the following devices: a sheet feeding device, arranged upstream of the cleaning apparatus, a collecting device, arranged downstream of the apparatus, a subsequent processing machine, for example a folding / gluing apparatus for sheets arranged immediately downstream of the cleaning apparatus, and a final collection device.

Brief description of the drawings A few preferred, but not limitative, embodiments of an apparatus according to the present invention will now be described. Reference is made to the attached drawings, in which: FIG. 1 is a schematic view in vertical and transversal cross section of a cleaning apparatus according to a first embodiment of the present invention; FIG. 2 is a schematic perspective view of the apparatus of FIG. 1; FIG. 3 is a schematic view in vertical and transversal cross section of a cleaning apparatus DynamicPDF for .NET v8.0.0.40 (Build 29393) Evaluating unlicensed DynamicPDF feature. Click here for details. [4:0:v8.0] 3 according to a second embodiment of the present invention; FIGS. 4 and 5 are a vertical cross-sectional view and a perspective view, respectively, of an apparatus according to a third embodiment; FIGS. 6 and 7 are a vertical sectional view and a perspective view, respectively, of an apparatus according to a fourth embodiment; FIGS. 8 and 9 are a vertical cross-sectional view and a perspective view, respectively, of an apparatus according to a fifth embodiment; and FIGS. 10 and 11 are a vertical cross-sectional view and a perspective view, respectively, of an apparatus according to a sixth embodiment.

Detailed description With reference to Figures 1 and 2, a driving system with pairs of opposing rollers 10, 11 causes the advancement of single sheets 12 of paper material, typically sheets of cardboard, paper or paperboard, at the output of a LASER machine (not shown) for processing such sheets. The structural and functional features of machines that use LASER technology to make cuts and / or creases on paper materials in sheets are known per se and do not need to be described in this context.

The advancement of the sheets, in the illustrated example, is produced by pairs of motor driven opposing transport rollers, driven in rotation at a given tangential speed, to produce the advancement of the conveyed sheets at a corresponding linear advancement speed. As an alternative to the rollers, the driving system may make use of pairs of conveyor belts, circulating at a given speed. In this context, terms and expressions indicating positions, directions and orientations such as "longitudinal" and "transversal", "front" and "rear", "upstream" or "downstream", should be construed with reference to the direction of advancement followed by sheets, indicated by the arrow A.

The sheets 12 transported by the driving system have an upper face 13 which may show, at the exit from the LASER machine, smudges or surface marks consisting of dust residues 14, particularly in the vicinity of edges and points where the LASER radiation has formed the vertex of a recess on the edge of the sheet.

DynamicPDF for .NET v8.0.0.40 (Build 29393) Evaluating unlicensed DynamicPDF feature. Click here for details. [4:0:v8.0] 4 A cleaning apparatus, suitable for removing dust residues 14 left by LASER radiation from the faces or upper surfaces 13 of the sheets, is designated in its entirety at 20. The cleaning apparatus comprises a strip 21 of flexible fibrous material, conveniently having a transverse width exceeding the width of the sheets. The strip is humidified to remove dust residues from the sheets coming out of the LASER technology processing machine by rubbing. The fibrous strip 21 is humidified and rubbed, in a humid condition, against the face 13, herein defined as upper face, of the sheets transported by the driving system.

The fibrous strip 21 is made of a material capable of absorbing moisture and resisting moderate tensile stresses without tearing. Preferably, the fibrous strip is of non-woven fabric.

The cleaning apparatus 20 comprises a motor driven lower feeding member 22, in this example a motor driven lower roller, for the advancement of the sheet to be cleaned. The motor driven feeding member 22 acts in the example of FIG. 1 against the lower face 15 of the sheets in transit. The face 13 to be cleaned is facing away from the motor driven feeding member, in this example facing vertically upwards and perpendicular to the horizontal direction of advancement of the sheet. In a different embodiment (not shown), as an alternative to the choice of a roller, the motor driven lower feeding member 22 may be a motor driven conveyor belt.

The lower motor driven feeding member 22 is located at the same height as the lower conveyor rollers or belts 11 of the driving system, to define with them a rectilinear feeding path for the sheets.

Preferably, the lower motor driven feeding member 22 has an external friction surface 23, for example rubberized, to exert a friction aimed at causing the advancement of the sheet which is cleaned from above by the humid fibrous strip.

The sheets conveyed by the driving system are brought one at a time into contact against the fibrous strip 21 along a transversely elongated contact area 25, identified by a pressing element 24, which presses the fibrous strip 21 towards the lower motor driven feeding member and against the upper face 13 of the sheets.

DynamicPDF for .NET v8.0.0.40 (Build 29393) Evaluating unlicensed DynamicPDF feature. Click here for details. [4:0:v8.0] The pressing element 24 may comprise at least one flexible metal blade inclined and forming a convex and transversely extended contact area acting against the fibrous strip. In the exemplary embodiment illustrated in FIG. 2, the pressing element 24 may comprise an array of flexible elastic blades 26, cantilevered and inclined in the direction of advancement of the sheets and towards the motor driven feeding member 22, transversely aligned and capable of elastically deflecting independently from one another.

According to an alternative embodiment (not shown), the elastic blades may be cantilevered downstream of the contact area 25 with the sheets and inclined towards the motor driven feeding member 22, in a direction opposite to the direction of advancement of the sheets.

According to a different embodiment, (FIG. 3) the pressing element 24 may comprise a pressure pad 24a of soft consistency.

The pressing element 24, 24a is part of a pressing device 27 which may advantageously comprise an adjustable means, associated with the pressing element 24, 24a, for varying the rubbing pressure on the sheet and in particular for reducing the impact of the leading edges of the sheets with the fibrous strip. In the example of Figures 1 and 2, the means that may adjust the pressure of the pressing element 24 is a vertically adjustable piston 28 which carries the pressing element 24.

Alternatively, or in addition to an adjustable member, the pressure device 27 may comprise one or more elastic elements, for example a set of springs (not shown) arranged to elastically bias the pressing element 24, 24a against the fibrous strip 21.

In order for the sheets to be rubbed by always clean sections of the fibrous strip, the latter is moved with respect to the pressing element by driving means, as described hereinafter. The movement of the fibrous strip may be continuous or intermittent.

The fibrous strip is unwound from a roll 30 of initially dry fibrous strip, mounted on an idle roller 31 and transported near a moistening device 32; then, the fibrous strip is passed between the pressing element 24 and the motor driven lower feeding member 22, and finally DynamicPDF for .NET v8.0.0.40 (Build 29393) Evaluating unlicensed DynamicPDF feature. Click here for details. [4:0:v8.0] 6 rewound on a motor driven winder roller 33.

The motor driven winding roller 33 may be driven to rotate at a tangential speed lower than the tangential speed of the lower motor driven roller, and therefore lower than the linear advancement of the sheets, so that the different speed of the fibrous strip with respect to the sheet causes rubbing of the upper surface of the sheet and cleaning of dust residues left by the LASER cutting machine.

The advancement of the fibrous strip is not aimed at causing rubbing on the sheets, which occurs due to the relative movement between the sheets and the fibrous strip, but at always having clean parts of the fibrous strip in contact with the sheets. Therefore, the linear speed and the direction of advancement of the fibrous strip, as well as the mode of advancement, continuous or intermittent, may vary according to requirements. By way of example, the linear speed of advancement or unwinding of the fibrous strip may be of the order of one tenth or even one hundredth of the linear speed of advancement of the sheets.

Alternative embodiments to those illustrated may provide feeding the fibrous strip in a direction opposite to the feeding direction of the sheets. Preferably, in order to avoid curling and creases in the fibrous strip, the fibrous strip is caused to advance in a direction concurrent with the direction of advancement of the sheets, but at a lower speed.

The moistening device 32 is arranged upstream, along the path of the fibrous strip, with respect to the pressing element, where the contact between the sheets and the fibrous strip takes place.

The moistening device 32 may be made in different ways. Preferably, the moistening device applies moisture to the fibrous strip. FIGS. 1 and 2 show a moistening device particularly effective in terms of uniformity of humification dosage and absence of splashes on the sheets during the cleaning phase. The moistening device of FIGS. 1 and 2 advantageously provides a moistening roller 34 which may be rotated and partially immersed in a tank 37 containing a cleaning liquid 38. The cleaning liquid may be water or an aqueous solution in which an antirust substance may be diluted. For certain applications, an essence to perfume the sheets DynamicPDF for .NET v8.0.0.40 (Build 29393) Evaluating unlicensed DynamicPDF feature. Click here for details. [4:0:v8.0] 7 may be diluted in the cleaning solution, since the LASER radiation may temporarily leave a smell on the treated sheets that recalls that of burnt paper.

The dry fibrous strip, unwound from the roll 30, is brought to lap the moistening roller 34, which has a transversal width suitable for including the entire width of the sheets in transit.

The moistening roller 34 has a cylindrical surface which may have one or more surface grooves 36 suitable for retaining the cleaning liquid and for releasing it in a distributed manner as uniformly as possible on the fibrous strip for a width suitable for covering the entire width of the sheets in transit.

The moistening roller 34 may be associated with a scraper blade or doctor blade 35, or a brush, which engages the cylindrical surface of the moistening roller to distribute and dose on the moistening roller the quantity of cleaning liquid to be supplied to the fibrous strip, removing the excess liquid from the surface of the roller.

A preferred embodiment (FIG. 2) provides one or more helical grooves 36 formed in the cylindrical surface of the moistening roller, which allow an optimal distribution of the liquid on the surface of the roller and therefore its uniform application over the entire width of the belt, combined with a continuous scraping action of the scraper blade or doctor blade or brush 35. Alternative embodiments (not shown) may provide a plurality of circular grooves transversely equally spaced along the cylindrical surface of the moistening roller.

According to some embodiments, the humidifying roller 34 may be driven to rotate at a predetermined angular speed. In order to improve the moistening uniformity of the fibrous strip, the moistening roller 34 may be arranged to rotate at a higher tangential speed than the speed of advancement of the fibrous strip 21. Certain embodiments provide that the rotation speed of the moistening roller 34 may be adjustable; for example, the rotation speed may be reduced and limited to avoid splashing of cleaning liquid.

The direction of rotation of the moistening roller 34 may be opposite to what is illustrated in FIG. 1, that is, it is not in line with the direction of advancement of the fibrous strip 21, so that, at equal speed of rotation of the moistening roller, the quantity of cleaning liquid DynamicPDF for .NET v8.0.0.40 (Build 29393) Evaluating unlicensed DynamicPDF feature. Click here for details. [4:0:v8.0] 8 transferred by the moistening roller to a unit of length of the fibrous strip, is greater.

Alternatively, according to other embodiments, the humidifying roller 34 may be an idle roller, driven in rotation by a portion of the fibrous strip which is brought into contact and stretched against it.

Alternative embodiments to that illustrated in FIGS. 1 and 2 may provide that the fibrous strip 21 is made according to a continuous loop, circulating along the path of a closed line, with a strip washing station located upstream (i.e. before, along the path of advancement and circulation of the strip) of the area 25 in contact with the sheets.

According to the embodiment illustrated in FIGS. 4 and 5, the moistening device 32 comprises a spray or drip or nebulization dispenser 39, which releases a metered quantity of aqueous cleaning solution on a transversely extended area of an upper opposing roller 10a, preferably associated with a lower motor driven transport roller 11. Alternatively, the lower motor driven transport roller may be constituted by a motor driven conveyor belt. Certain embodiments may provide delivery of the cleaning solution to be programmed.

The upper opposing transport roller 10a has the function of humidifying the upper faces 13 of the sheets. The upper opposing roller 10a, therefore, acts as a moistening roller and may be associated with a scraper blade or brush 35 which engages the cylindrical surface of the moistening roller to dose the quantity of liquid supplied to the sheets, uniformly distributing the cleaning liquid on the humidifying roller and removing from the humidifying roller the excess liquid.

According to the embodiment illustrated in FIGS. 6 and 7, the moistening device 32 comprises a spray or drip or nebulization dispenser 39, similar to that illustrated in FIGS. 4 and 5, which releases a metered quantity of aqueous solution on an area of the fibrous strip 21 located upstream of the area 25 of contact between the fibrous strip and the sheets.

In the variant embodiment of FIGS. 8 and 9, the moistening device 32 comprises a spray or drip or nebulization dispenser 39, similar to that illustrated in FIGS. 4 and 5, which releases DynamicPDF for .NET v8.0.0.40 (Build 29393) Evaluating unlicensed DynamicPDF feature. Click here for details. [4:0:v8.0] 9 a metered quantity of aqueous cleaning solution on a transversely extended area of an upper opposing roller 10a, preferably associated with a motor driven lower transport roller 11 (or a motor driven conveyor belt). The upper roller 10a distributes a metered and uniform quantity of cleaning solution on the upper faces 13 of the sheets to be cleaned. Downstream of the moistening device 32, a fibrous strip 21a is wound around an upper opposing roller 10b, associated with a lower motor driven feeding roller (or belt) 22. The upper roller 10b acts as a cleaning roller. The cleaning roller 10b is sized and rotated in such a way that the fibrous strip 21a moves at a different tangential speed, preferably greater than the tangential speed of the lower roller or belt 10b for transporting the sheets.

Embodiments may provide that one or more air jet dispensers 40 are associated with the cleaning roller 10b equipped with the fibrous strip 21a. The air jets emitted by the dispensers 40 impinge on the fibrous strip in a substantially tangential way, giving rise to a drying action. Optionally, by adjusting the power of the jets, air coming out of the dispensers 40 may remove dirt residues and liquid droplets from the surface of the cleaning roller 10b. A suction hood 41 may be arranged adjacent the cleaning roller 10b for receiving air jets emitted by the air dispensers 40 with the residues carried by them and removing through an ejection tube 42 the collected dirt and the partly vaporized liquid sucked in from the hood 41.

According to the embodiment illustrated in FIGS. 10 and 11, to remove dirt from the fibrous strip 21a, a rotating brush 43 may be used, for example with felt blades, counter-rotating with respect to the cleaning roller 10b and sliding against the fibrous strip 21 to collect dirt residues removed from the sheets 12. The rotating brush 43 may be impinged tangentially by a jet of air emitted by a blower 44 which cleans and dries the rotating brush and removes from the rotating brush dirt residues and part of the humidity coming from the fibrous strip.

Dirt residues and cleaning liquid may be collected off the rotating brush 43 by a collecting wall 45, for example a sheet metal, acting tangentially against the rotating brush 43, and / or by a suction hood (not shown) similar to that illustrated in FIGS. 8 and 9.

According to further embodiments (not shown), two cleaning apparatuses may be provided consecutively arranged along a line of advancement of the sheets, with a first apparatus, for DynamicPDF for .NET v8.0.0.40 (Build 29393) Evaluating unlicensed DynamicPDF feature. Click here for details. [4:0:v8.0] example similar to that of FIG. 1, acting on the upper face 13 of the sheets and a second cleaning apparatus acting on the lower faces 15 of the sheets.

The sheets that are fed to the cleaning apparatus may come directly from a LASER processing machine, or from a sheet feeder device. After cleaning, the sheets may be stacked or forwarded to other machines for further processing.

Certain embodiments of the present invention may provide that the cleaning apparatus is incorporated within a sheet processing machine with LASER technology.

Other embodiments of the present invention may provide that the cleaning apparatus is an independent apparatus, which receives the sheets from a sheet feeder device, arranged upstream of the cleaning apparatus, and supplies the cleaned sheets to a collecting device located downstream of the apparatus.

Additional processing apparatus may be associated with the cleaning apparatus. For example, according to further embodiments of the present invention, the cleaning apparatus may be incorporated in a finishing machine comprising, in addition to the cleaning apparatus, a sheet feeding device arranged upstream of the cleaning apparatus, a subsequent processing machine, for example a sheet folding / gluing apparatus arranged immediately downstream of the cleaning apparatus, and a final collection device.

Different aspects and embodiments of the cleaning apparatus have been described. It is to be understood that each embodiment may be combined with any other embodiment.

Furthermore, the present invention is not limited to the embodiments described, but may be varied within the scope of protection described and claimed herein.

Claims

1.CLAIMS 1. Apparatus for cleaning sheets (12) of paper material, comprising: a motor driven feeding member (22), for advancing a sheet (12) in a given direction (A) of advancement, and presenting a face (13) of the sheet (12) to be cleaned facing away from the motor driven feeding member (22), a fibrous strip (21), opposed to said motor driven feeding member (22) and configured for wiping the face (13) to be cleaned of a sheet (12) advancing on the motor driven feeding member (22), a pressing device (27), for urging the fibrous strip (21) towards the motor driven feeding member (22) and against the face (13) to be cleaned of the sheet (12) advancing on the motor driven feeding member, the pressing device providing a transversely elongated contact area (25) where the face (13) to be cleaned of the sheet advancing on the motor driven feeding member (22) is wiped by the fibrous strip (21), and a moistening device (32), adapted to humidify the fibrous strip (21) or the faces (13) to be cleaned of the sheets (12) advancing in an area upstream of said contact area (25), whereby the face (13) of a sheet (12) contacted by the humid fibrous strip (21) is cleaned by wiping, with consequent removal of residues from previous cutting and/or creasing operations carried out by a LASER technology processing machine.

2. Apparatus according to claim 1, wherein the pressing device (27) comprises at least one pressing element (24) in the form of an inclined flexible plate forming a convex and transversely extended contact zone which identifies the transversely extended contact area (25) with the fibrous strip (21).

3. Apparatus according to claim 2, wherein the plate of the pressing element (24) is cantilevered and inclined towards the motor driven feeding member (22) and in the direction (A) of advancement or in the direction opposite to said direction (A).

4. Apparatus according to claim 2 or claim 3, wherein the pressing element (24) comprises a plurality of said flexible plates (26) transversely adjacent.

5. Apparatus according to any one of the preceding claims, wherein the pressing device (27) comprises an adjustable means (28), associated with the pressing element (24), for varying the wiping pressure exerted by the pressing element (24, 26) against the fibrous strip (21).

6. Apparatus according to claim 5, wherein the adjustable means (28) comprises a vertically adjustable piston to which the pressing element (24, 26) is mounted.

7. Apparatus according to any one of the preceding claims, further comprising motor means for moving the fibrous strip (21) relative to the pressing device (27).

8. Apparatus according to claim 7, wherein the motor means for moving the fibrous strip (21) comprise an idle roller (31) adapted to support a roll (30) of fibrous strip, and a motor driven winding roller (33), where one of said rollers (31 or 33) is arranged upstream of the contact area (25), and the other of said rollers (33 or 31) is arranged downstream of the contact area (25).

9. Apparatus according to claim 7, wherein the fibrous strip (21) defines a closed loop and the means for moving the fibrous strip (21) comprise at least one motor driven roller and idler rollers for circulating the fibrous strip in said contact area (25).

10. Apparatus according to any one of the preceding claims, wherein the moistening device (32) comprises a rotatable moistening roller (34) partially immersed in a tank (37) containing a cleaning liquid (38), and wherein the fibrous strip (21) contacts the moistening roller (34).

11. Apparatus according to claim 10, wherein the moistening roller (34) has a cylindrical surface with one or more grooves (36) configured to retain cleaning liquid (38) taken from the tub (37) and distributing this liquid uniformly on the fibrous strip (21).

12. Apparatus according to claim 11, wherein the grooves (36) comprise one or more helical grooves formed in the cylindrical surface of the moistening roller (34).

13. Apparatus according to any one of claims 10 to 12, wherein the moistening roller (34) is motor driven to adjust its angular speed and/or direction of rotation.

14. Apparatus according to claim 1, wherein the fibrous strip (21a) is wound around a motor driven pressure roller (10b) opposing the motor driven feeding member (22) and rotated with a tangential speed being different and preferably greater than the tangential speed of the motor driven feeding member (22), wherein the pressure roller is able to urge the fibrous strip (21a) towards the motor driven feeding member (22) and against the face (13) to be cleaned of the sheet (12) advancing on the motor driven feeding member, and wherein the moistening device (32) is arranged to humidify a roller (10a) arranged upstream of the motor driven pressure roller (10b) along the direction of advancement (A) of the sheets (12).

15. Machine for processing sheets with LASER technology, in particular a LASER cutting machine, comprising a cleaning apparatus according to any of the preceding claims. Roy S. Melzer, Adv. Patent Attorney G.E. Ehrlich (1995) Ltd. 11 Menachem Begin Road 5268104 Ramat Gan