EP1442858A9

EP1442858A9 - A method of producing veneered doors

Info

Publication number: EP1442858A9
Application number: EP20040001297
Authority: EP
Inventors: Claudio Cesare Botto
Original assignee: ITALPORTE SpA
Current assignee: ITALPORTE S.P.A
Priority date: 2003-01-29
Filing date: 2004-01-22
Publication date: 2009-07-29
Also published as: ITTO20030052A1; EP1442858A1; UA35709U; PL207786B1; PL364616A1; RU2004102581A; RU2347055C2

Abstract

The method comprises basically the steps of providing an outer covering panel comprising a sheet of decorative furniture paper reproducing the appearance of a predetermined type of wood and of fixing the outer covering panel to the internal structure of the door leaf (10). According to the invention, the step of providing the covering panel in turn comprises the steps of providing a sheet of decorative furniture paper printed so as to have a pair of lateral edge portions (13) with a longitudinal grain and a central portion (14) with a transverse grain, and of applying the sheet of decorative paper to the outer surface of a wood substrate so as to obtain the outer covering panel to be fixed to the internal structure of the leaf (10).

Description

The present invention relates in general to a method of producing veneered doors and, more particularly, veneered doors having panels that are covered with sheets of decorative furniture paper. In the description and in the claims which follow, the expression "sheets of decorative furniture paper" is used to indicate not only actual sheets of paper printed so as to reproduce the appearance of wood but, in general, sheets of any other material (for example, of plastics material such as PVC) which can be subjected to a printing process in order to adopt an appearance similar to that of wood.
In order to produce low-cost wooden doors, it is known to use the so-called veneering process which consists in applying to the frame of the door leaf, which is made of low quality wood, one or more covering panels each composed of a series of strips of wood (for example, fir), a wood-pulp substrate, and an outer, thin layer of good quality wood (of the order of a few tenths of a millimetre thick).
The veneering method is advantageously used to produce so-called imitation heartwood doors, that is, doors the leaves of which reproduce the contrast effect between the vertical grain of the two vertical side elements of the leaf (the stiles) and the horizontal grain of the horizontal elements of the leaf (the rails) which extend between the two stiles. With the use of the veneering technique, the imitation heartwood effect is achieved simply by applying a panel with a vertical grain in the region of each stile of the leaf and a panel with a horizontal grain in the region of each rail.
Novel materials such as sheets of decorative furniture paper have recently been introduced for the production of the outer layer of veneering panels the paper being subjected to a special printing process in order to reproduce faithfully the colour and grain of natural wood and then impregnated with melamine resins.
The object of the present invention is therefore to provide a method of producing veneered, imitation heartwood doors that are covered with decorative furniture paper.
This object is achieved in full according to the invention by means of a method of producing veneered doors having the characteristics defined in independent Claim 1.
The invention will be described in greater detail below, purely by way of non-limiting example, with reference to the appended drawings, in which:

Figure 1 is a front elevational view of a veneered, imitation heartwood door leaf produced by means of a method according to the present invention,
Figure 2 shows a sheet of decorative paper to be used as an outer covering in the method of producing veneered, imitation heartwood doors according to the present invention,
Figure 3 shows an apparatus for the preparation of cylinders for printing rolls of decorative paper as shown in Figure 2, and
Figure 4 shows an experimental printing apparatus for checking the correct operation of the printing cylinders prepared in the apparatus of Figure 3.

With reference to Figure 1, a veneered, imitation heartwood door leaf is generally indicated 10 and, in the embodiment shown, has a pair of glazed openings 11 and 12, that is, an upper opening and a lower opening, respectively. As can be seen, the veneer reproduces the contrast effect between the vertical grain of a pair of vertical side portions 13, or imitation stiles, and the horizontal grain of a series of central horizontal portions 14, or imitation rails, which extend between the two imitation stiles and delimit the openings 11, 12 at the top and at the bottom. Naturally, in a heartwood door, that is, a door without glazed openings, a continuous central portion with a horizontal grain will extend between the two imitation stiles.
The method of producing a veneered door leaf according to the invention will now be described with particular reference to the method of producing the covering panel to be applied to the internal structure of the leaf in order to confer thereon the above-described imitation heartwood effect.
The first step of the method consists in producing the sheet of decorative paper intented be applied to the outer surface of the veneering panel to be fixed to the internal structure of the door leaf. For this purpose, a roll of decorative furniture paper of per-se-known type is subjected to a printing process by means of which both the vertical grain (that is, the longitudinal grain with reference to the direction of unrolling of the roll of paper) and the horizontal grain (that is, the transverse grain) are printed simultaneously. A piece of printed decorative paper sheet according to the present invention is shown schematically in Figure 2.
The decorative paper is printed by the superimposition of a series of print layers each of which is produced by a respective printing cylinder 16. Each printing cylinder is prepared by means of a suitable apparatus, generally indicated 15 in Figure 3.
The main difficulty to be overcome in performing two-directional printing, that is, printing which provides both for a pattern extending longitudinally and for a pattern extending transversely, is represented by the different colour setting that is required when printing in the longitudinal direction, in comparison with that required when printing in the transverse direction. In fact, the movements of the longitudinal register of the printing machine may give rise to a longitudinal offset between the various print layers and hence to a blurred effect in the transverse grain of the pattern, which reduces the final print quality to an unacceptable level. To overcome this drawback, the design of each print layer is defined so as to exclude any obligatory point of coincidence, or of intersection, between the layers, by means of the use of various blurring filters.
In figure 4 there is shown an apparatus, generally indicated 17, in which the various types of printing paper are tested and the colour setting is performed in order to determine the correct printing definition. The definitive data for proceeding to the engraving of the printing cylinders by means of the apparatus 15 (Figure 3) is derived from the experimental results obtained.
After printing, the paper is impregnated in per-se-known manner with melamine resins which enable to give the paper the final appearance of a wooden door panel.
The impregnated paper is supplied in stiff sheets of predetermined format, for example 2440 mm x 1830 mm which, at this point, have to be arranged perfectly in alignment on wood or wood-pulp substrates so as to form the veneering panels to be applied to the door. To ensure precise alignment between the impregnated paper and the wood or wood-pulp substrate, a reference line of a very clear colour (a dark colour on light woods and a light colour on dark woods) is drawn on the printed paper for a set of laser devices of an alignment station which are intended to guide the sheet of paper on the wood substrate. This alignment station is disposed at the input of a press in which the wood substrate and impregnated paper assembly is subjected to predetermined pressure and temperature conditions so as to give rise to the chemical reaction which causes the melamine resin of the paper to fuse onto the surface of the wood substrate, thus enabling to produce a single panel having the superficial appearance of wood.
The panel thus produced is then applied to the door leaf by the method generally used for the production of veneered doors.
Naturally, for a door provided with windows, it is also necessary to form openings of suitable size and shape.
It can easily be understood from the foregoing description that the main advantage of the invention is that the simultaneous printing of both the vertical grain and the horizontal grain enables a single panel to be produced for application to the door leaf without the need to perform various cutting and gluing operations which would increase the processing time and the number of rejects.
Naturally, the principle of the invention remaining the same, the embodiments and details of construction may be varied widely with respect to those described and illustrated purely by way of non-limiting example, without thereby departing from the scope of the invention as defined in the appended claims.

Claims

A method of producing a veneered door, of the type comprising the steps of:
a) providing an outer covering panel comprising a sheet of decorative furniture paper reproducing the appearance of a predetermined type of wood, and of

b) fixing the outer covering panel to the structure of the door leaf (10),
characterized in that step a) comprises the steps of:
a1) providing a sheet of decorative furniture paper printed so as to have a pair of lateral edge portions (13) with a longitudinal grain and a central portion (14) with a transverse grain, and

a2) applying the sheet of decorative paper to the outer surface of a wood substrate so as to obtain the said outer covering panel to be fixed to the internal structure of the leaf (10).
A method according to Claim 1, characterized in that said step a1) comprises the step of printing a roll of decorative furniture paper of a width substantially equal to that of the door leaf (10) and cutting from the roll a sheet having a height substantially equal to that of the door leaf (10).