Printing – Stenciling – Stencils
Reexamination Certificate
2000-03-31
2003-08-26
Yan, Ren (Department: 2854)
Printing
Stenciling
Stencils
C101S128400, C101S129000
Reexamination Certificate
active
06609457
ABSTRACT:
The present invention relates to a stencil of the type including a support forming a design or pattern that is to be transferred onto a surface to be printed, with a non-planar profile and, in particular, a convex profile. The stencil according to the invention is most particularly suited to producing designs or patterns printed on hair or other certain parts of the body.
Stencils have been widely used for producing designs or patterns printed on flat surfaces. Typically, a stencil of this kind is made of a relatively rigid support from which is cut the pattern that is to be produced. The support is applied to the element that is to be decorated, and a colorant is applied so as to deposit the colorant onto the surface that is to be printed and do so in the pattern defined by the design made in the support. The colorant may be applied using a brush or an applicator, particularly of the cellular foam type, pierced at its center with a duct communicating with a container on which the foam is mounted. This technique is used particularly for interior decorating or in the field of cosmetics for applying body make-up. It works entirely satisfactorily when the surface to be decorated is flat or approximately flat.
Problems arise when this technique is to be used for decorating non-planar surfaces, such as the hair, or certain convex surfaces of the body. This is because the center of the pattern can easily be applied at the desired point using a rigid stencil of the type described hereinabove but, because of the curvature of the head or other body areas, the edges of the pattern are not clearly defined.
Making the stencil from a support made of flexible material does not satisfactorily solve the problem in so far as its use requires the stencil to be held in place on the scalp at the same time as application of the product. Experience has shown that, particularly on account of the difficulty of holding the flexible support in position on the head, it is difficult to apply the product to the hair without calling on a third party for assistance.
Thus, one of the objects of the invention is to produce a stencil suited for decorating or applying make-up to non-planar surfaces, and this stencil at least partially solves the aforementioned problems.
In particular, one object of the invention is to produce a stencil, suited in particular to applying make-up to the hair or applying body make-up, that someone can use without requiring the help of a third party.
Another object of the invention is to produce a stencil which is simple to use and economical to produce.
It should be understood that the invention could still be practiced without performing one or more of the preferred objects and/or advantages set forth above. Still other objects will become apparent after reading the following description of the invention.
To achieve these and other advantages, and in accordance with the purposes of the invention, as embodied and broadly described herein, the invention includes a stencil. The stencil comprises a substantially flexible sheet bearing a pattern that is to be reproduced on a convex surface. One region of the sheet, located near a peripheral edge, is attached to a substantially rigid frame, the flexible sheet being mounted on the frame in such a way as to form a dome inside the frame. Preferably, the frame has a substantially annular shape, but the invention in its broadest aspects could be practiced with many differently shaped frames.
Preferably, the substantially rigid frame allows the stencil to be positioned at the desired point, particularly on the head, and held in place there with ease. The flexible sheet bearing the design that is to be reproduced can be permanently shaped to the curvature of the surface that is to be decorated. The action is simple, and application may be performed without having to involve a third party. By way of indication, the stencil may have a diameter that may be of the order of 10 cm to 15 cm. The rigidity of the frame is at least such that this frame remains in shape in the absence of appreciable stress and, in particular, does not deform under its own weight. The radius of curvature formed by the dome of the flexible sheet is of the same order as the radius of curvature of the surface that is to be decorated, so that the entire design can rest against the surface that is to be treated.
The flexible sheet is preferably not elastically deformable (in the case of a multi-layer sheet, at least one of the layers is made of a material which is not elastically deformable) so that the pattern, produced by removing material, does not deform during application.
As a preference, the peripheral region by which the flexible sheet is attached to the frame has an inner edge and an outer edge, the inner edge having a radius R smaller than the radius R+&egr; which that portion of the flexible sheet that extends inside the inner edge would form if the flexible sheet were not secured to the frame.
Advantageously, 1.01 * R≦R+&egr;≦1.05 * R. More preferably, 1.01 * R≦R+&egr;≦1.02 * R.
Such differences in radii are particularly advantageous in that they can be achieved entirely naturally by a phenomenon known as “post-shrinkage” which is observed when molding materials such as thermoplastics. In general, “post-shrinkage” in the sphere of molding is seen as a constraint that has to be accounted for in the molding process when determining the operating parameters thereof.
Advantageously, the frame is formed of at least two parts which can be folded one onto the other. Thus, a structure is produced that makes it possible to obtain a relatively large-sized pattern for printing (particularly from 10 to 15 cm), but which can be folded so as to occupy less space in the storage position. For this purpose, the parts of the annular frame may be connected together by an articulation, particularly of the film hinge type.
According to a preferred embodiment of the invention, the rigid frame is obtained by molding a first thermoplastic in a mold, in one plane of which is held the flexible sheet, already formed and cut to the desired size and shape, the sheet having at least one layer of a second thermoplastic which is physico-chemically compatible with the first thermoplastic, so as to allow the frame to attach to the flexible sheet along the peripheral attachment region. Physico-chemically compatible materials are materials which, in the molten or softened state, are able to weld together.
This characteristic of the stencil according to the invention is quite particularly advantageous in that it makes it possible to obtain a uniform dome, making it possible to obtain a printing pattern with a very sharp outline. Specifically, the advantageous effect of such a characteristic stems from the “post-shrinkage” phenomenon described previously, which is observed in the molding processes, particularly the molding of thermoplastics.
In practice, there are several advantageous aspects associated with producing the stencil by molding, using a technique similar to the so-called In-Mold Labeling (IML) technique, known in the field of labeling certain objects which are made of thermoplastic, particularly bottles.
On the one hand, it allows the peripheral edge of the sheet to be attached to the rigid frame in a perfectly uniform way with no creases or other irregularities. This is because attachment (which occurs by localized “fusion” of mutually compatible materials) of the peripheral edge of the flexible sheet to the annular frame occurs almost instantaneously when the first molten thermoplastic is injected under pressure, this fusing being with a sheet held flat in the mold. As a preference, the attachment region extends continuously over 360°.
On the other hand, because of the “post-shrinkage” of the material of which the frame is made, the sheet, the peripheral edge of which was secured to the rigid frame beforehand, is forced, under the effect of centripetal forces applied uniformly over 360°, to deform into the shape of a homogeneous dome, able in particular to app
Finnegan Henderson Farabow Garrett & Dunner LLP
L'Oreal (S.A.)
Yan Ren
LandOfFree
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