FR2984088A1 - Method for treating hair to realize colored or discolored thicker wicks, involves evolving coloring or bleaching property of hair with composition in pre-defined manner to obtain evolution of property of composition along hair - Google Patents

Abstract

The method involves evolving coloring or bleaching property of hair (C) with a composition in a pre-defined manner so as to obtain an evolution of the property of the composition along the hair after contacting the composition with the hair. A gradient of coloring or bleaching on the hair is obtained. Formulation of the composition is modified. An outlet distributing the composition is moved in a motorized manner relative to a hair lock or with a support to be applied to the hair lock during the distribution of the composition. An independent claim is also included for a system for obtaining a coloring or bleaching in gradient on hair.

Description

The present invention relates to the field of hair dyeing and, more particularly, to the production of hair gradients. <br/> <br/> <br/> BACKGROUND ART In the field of dyeing The techniques used conventional -1 or hair dyeing are intended to obtaining uniform colors or obtaining locks having a different color from the rest of the hair Tests have been conducted to create heterogeneities in the hair, applying one color and then another, for example, a blond color on the first half of the lock and a brown color on the second.The results obtained at the end of these tests may be considered as unsightly and, in general, treated as a coloration obtained after hair regrowth. In some cases, the hair being sensitized, a staining treatment can give heterogeneous results and can be considered as 1 5 unsightly because marked by abrupt transitions from one color to another. It is, moreover, known to treat locks to give the hair an appearance approaching that produced by exposure to the sun. The hairdresser then isolates a few locks and applies a bleach. In the case of light hair (blonde or blonde hair that has been dark for 20 days), we obtain a result that can be considered relatively aesthetic but often considered as unnatural. The aesthetic nature comes from the fact that each faded wick flares towards the tips and thus the light hair merge somewhat with the other hair of the tips. By this flaring effect, the two colors contrast very little with respect to each other. The unnatural nature comes from the roots. Indeed, by approaching the roots, the locks hair tighten against each other, producing if an effect of sheaves unnatural due to a contrast of colors. Thus, the locks can give a relatively natural appearance at 30 points and at mid-length, while the roots can produce an artificial appearance. In order to reduce the artificial appearance of the roots, it could be envisaged to lessen the hair of the treated locks. However, such a solution decreasing the visibility of thinning may not be satisfactory. Indeed, to produce reasonably visible wicks, it may be necessary to lighten by about 4 tones, such a gap making the roots unnatural. Another approach is to isolate and treat very fine wicks. However, this approach is expensive because of the time spent by the hairdresser and does not really solve the problem of the visibility of the roots. Another approach is to make the wicks from the scalp. However, this approach can lead to over-clarification. There is a need for a method for producing thicker or more aesthetic colored or discolored wicks in order to limit the time spent and make the service less expensive. There is also a need to make locks on dark hair (light brown, chestnut, dark chestnut or brown), flow. try to treat brown hair without having to clear them first. The invention aims to meet all or part of the aforementioned needs. SUMMARY According to a first of its aspects, the present invention relates to a hair-hacking method, comprising the step of predefinitely changing at least one coloring or bleaching property of the hair of a composition, from after contacting said composition with at least the hair, an evolution of said property of the composition along the hair, resulting in obtaining a gradation of coloration or discoloration on the hair. Evolution can be achieved automatically. By "automatically" it must be understood that evolution is achieved. that the user has to pay special attention to change the coloring property or bleaching. For example, the evolution is linked to a setting that changes in the independent way. t ent of any action of the user, the depletion of an applicator in composition as its distribution or a stimulus whose evolution in time is predefined. Evolution can also take place in response to an action by the user not aimed directly at obtaining this evolution, for example by moving along a support or hair, the user having no control of evolution during this movement. The invention p and reproducibly achieve an aesthetic gradient on the hair and thus to overcome the above disadvantages 5 regarding the treatment of the locks according to the prior art. The evolution of a property of the composition offers a wide range of possibilities regarding how the color changes along the wick and makes hair treatment easier. The gradient can be obtained in many ways, depending on how the composition acts to change local hair color, especially as it acts by dyeing or bleaching more or less hair. It is possible to act automatically on a control means, flow ent of a mixing device, modifying the formulation of the composition during its distribution. In particular, it is possible to act on the control means via an electrically controlled member or via a member whose movement is purely mechanical. that, especially obtained by a return spring. An outlet distributing the composition relative to the lock of hair, or better still, to a support to be applied to the lock of hair, during the dispensing of the composition, of which the formulation distributing the neck, can be motor-driven. Alternatively, a positional output relative to the lock of hair or a carrier to be applied to the lock of hair may be moved manually during dispensing of the composition. In this case, he is p. It is particularly advantageous for the formulation to evolve automatically, since the user can concentrate on moving the outlet 25 relative to the surface intended to receive the composition, which makes its task easier. The invention allows, if desired, to achieve locks on dark hair (chestnut, chestnut, dark chestnut or brown), without harming the aesthetics, thanks to the presence of the gradient. The composition may have a formulation which is due to the use of color active ingredients whose proportions v. in the distributed mixture, eg over the distance from a starting point, this variation may be linear or not. In order to obtain a variation of the coloration, it is possible to modify the content of a dye or an ingredient having a role in the development of the colonel effect, whether it be a coloration or a discoloration, by ex-t strength of an oxidant, a pH agent, or an amount into an inhibitor. In a first example of implementation of the invention, two compositions are prepared, one capable of giving a first color and the other capable of giving a second color, and in which a device is used. which dispensing the two compositions in variable relative quantities, this v 'ation being carried out automatically, either on the hair, for example by sliding the device along the hair, or on an application element such as an applicator paper, which can be used to wrap a wick. It is also possible to proceed by preparing a first coloring or bleaching composition which is placed in an applicator device and automatically instilling an increasing or decreasing amount of a second composition, which acts as an inhibitor of the effectiveness. of the first composition. In another embodiment of the invention, a device capable of dispensing a composition whose coloring or bleaching power varies under the effect of a s-ulus is used, and the composition is automatically varied. intensity of this stimulus during the distribution of the composition or on a repository composition already applied so as to modify a coloring property or bleaching thereof. For example, the device comprises a heating or dispensing nozzle and the device heats or irradiates gradually at the outlet of the composition to gradually activate the composition, then applied to the hair or to an application element. such as an applicator paper. In one particular embodiment, an applicator tip can be used as a resist. Thus, the gradient composition is advanced in the tip, which is used later or thereafter, to dispense the composition gradient on a sheet or the hair. It is therefore possible to use a device whose end is filled with a gradient composition which is then distributed over the hair or on the head. When the user applies the composition to a wick, said device may be configured to allow filling of the tip with a gradient composition snde. It is also possible to apply a composition containing an activator or bitter to the hair in a variable amount, with an automatic variation of the quantity, then to apply the dyeing composition, for example manually, the coloring composition possibly containing at least one dye. insensitive to the composition cont t activator or 1 '. 'Debtor. This composition containing the activator or bitumen can be applied directly to the hair, or through an application element such as an applicator sheet. The composition containing the activator or the Ut may also be applied according to other principles, such as for example a roll which is automatically exhausted as it unfolds, or a spray whose flow changes automatically. .

The coloring composition can be applied without a gradient or with a gradient of its amount along the deposit. During the second approach above, a coloring composition can be applied to the hair, followed by a composition containing an activator or inhibitor. This composition containing the activator or inhibitor may be applied directly to the hair, or through an application element such as an applicator sheet. This composition can also be applied according to other principles, such as for example a roll that runs out as it unfolds, or a spray whose flow changes. The coloring composition can be applied without gradient or gradient.

Another approach is to sensitize or sensitize in a v. the hair, by means of a sensitizing compound such as a thiol, the sensitizing compound being applied with a variable amount, automatically. Then, the composition is applied whose coloring effect is variable according to the level of sensitization of the hair. This composition can be applied without gradient or with gradient. If necessary, a gradient can be made by application to an increasing number of hairs. It is possible to compare, over the distance, the number of hair that will receive the composition or compositions leading to obtaining a gradient. Thus, it is possible to use a band provided with fine r's. tures. The hair is placed in the grooves. As and when moving a growing or decreasing number of grooves will deliver the composition or compositions leading to obtaining a gradient. This system of grooves may, therefore, permit the dispensing of an increasing amount of composition as the displacement proceeds. A device comprising a comb according to the principle is also possible. A composition deposit with an automatically varying amount can result from the application of a prespecified variable pressure, flow at a low starting pressure, and then a gradual increase in pressure, to create an air flow. the quantity applied. The pressure is for example applied to at least two sponges arranged one after the other in the direction of the hair. At least one of the sponges 15 receives a variable pressure or is arranged to create progressive exhaustion, automatically. It is also possible to use a cylinder-shaped sponge having two compositions on each hemisphere. The equipment will progressively move the cylinder so that at the beginning of the movement, it is the first hemisphere 20 which is in contact with the hair, then progressiv-1 ent it is the second hemisphere which becomes in contact with the hair. In one case p. In particular, in the case where it is desired to treat an entire head, it is possible to take a large quantity of hair and carry out the application over a whole section of the hair, for example a sheet of 1 /. 2 cm to 1 cm 25 wide for a length of 20 cm. Thus, one can share the hair in a series of layers, for example thirty or so for the whole of the hair. Each sheet receives a gradient, then protects for example the sheet by a sheet of paper. For such an application, a suitable applicator is preferably used, which follows the curvature of the skull and contains a series of teeth which will distribute the composition in order to obtain the gradient.

The method according to the invention can be implemented using a system arranged to calculate the gradient to be made as a function of the length of the hair to be treated. For example, the system is told the length of the hair. A computer integrated in the system allows for example adapt the flow of two components to obtain a variation of the mixture adapted to the length of the hair. The system can be arranged to identify the user's choice of a gradient based on the length of hair. In the case where several pretreated sheets are available, the user indicates the length of the hair and the system is arranged to propose the adapted sheet. The system can be arranged to allow an aesthetic evaluation of the gradients on strands or not, in order to apprehend through simulation the result. The system can be arranged to control the production of a gradient, for example to make sheets ready for use, depending on the result simulated and accepted by the user. The process according to the invention may comprise the application of a direct, acidic, basic coloring composition comprising nitro compounds, anthraquinone, oxidation dyeing, lightening, discoloration, d a composition which produces optical brightening by the use of at least one fluorescent compound. The composition may be a hybrid coloring composition, especially a coloring composition based on reactive compounds other than oxidation dyes, for example polyphenols, hydroxyindoles, with or without catalysts or oxidants. The variability of the coloring or bleaching power of the composition may result from the mixing of two components in varying proportions; thus one can use a device that p and an automatic evolution of the formulation to mix these two components. The variability of the coloring or bleaching power can still result from the action of an energetic energy on the composition, for example a thermal or light stimulus, when the composition is formulated so as to have a variation of its coloring power. or discolourant when exposed more or less to this stimulus. In this case, the method can implement a device comprising means for exposing the composition to this stimulus so as to make there er its coloring or decolorizing power along the wick. The coloring or discoloration composition may be distributed by the device used according to the invention directly on the hair. In there. ante, the composition is distributed on an intermediate support before being applied to the hair. The automatic control of the device for dispensing the composition and / or subjecting it to a stimulus can be performed after acquiring at least one par. to be entered by the user, in particular a function of evolution along the lock of hair to be treated with at least one color characteristic of a coloration or gradient discoloration to be obtained, and / or at least one geomatic characteristic 'than a lock of hair to treat. This entry can be made by intennédi. e a user interface such as a keyboard, a touch screen, a voice recognition, among other possibilities. The aforementioned evolution function can be an affine or asymptotic function. The automatic control of a device mel. Stimulation generation or generation can be effected according to a predefined evolution of h20 and / or saturation C * of the gradient to be obtained. The automatic control can be performed according to the hue of at least one region delimiting the gradient to obtain, no. enter a hue entered by the user. The automatic control can still be carried out according to the length of the gradient to be obtained and / or the length of the wick to be treated, in particular a length of gradient and / or a wick length entered by the user. When the composition is delivered while the dispensing device is moved relative to the wick, the position of the device along the wick may optionally be detected and taken into account in the control of the device to change the property of the composition. along the wick. The control of the device can be carried out at least according to a value of a gradient colonel of the gradient to be obtained, in particular a value entered by the user. The method may comprise a step of simulating the gradient to be obtained before carrying out said gradient on the hair. Another subject of the invention, according to another of its aspects, is a system for obtaining a gradient coloration or discoloration on the hair and no. ent for implementing the method according to the invention, comprising a device for obtaining a composition having at least one coloring or bleaching property of the hair which evolves in a predefined manner so as to obtain, after contacting the composition with at least one lock of hair, an evolution of said property of the composition along the lock of hair, leading to obtaining a gradation of coloring or discoloration on this lock. The device may be arranged to present such a change automatically during use, for example by exhaustion of an application means into a compound or modification of an adjustment under the action of a return member elastic. The system can also be more complex and include an imitation of control controlling the device, including an adjuster thereof. The control unit can be connected to a perme interface. t to enter at least one by. according to which the device is controlled, in particular a par. - be related to the appearance of the gradient to be made and / or a characteristic of the wick to be treated. The device may comprise two reservoirs containing two components to be mixed and a mixer for mixing said components, the composition having a coloring or bleaching property varying according to the relative proportion of said compounds in the mixture, the device being arranged so as to the control unit to control said proportion as the mixture is dispensed. The system can be arranged to deliver the composition progressively, with a variation of a coloring or decolouring property, along the wick. The system may also be arranged to deliver the composition on an intermediate support before transfer to the hair. The system may include an airbrush for delivering at least one component of the composition or a cannula, preferably provided with a mixer.

The composition can be delivered by multiple orifices, for example to allow the simultaneous treatment of several locks. The system may comprise a means of simulation of the coloring or gradual fading to obtain, to facilitate for example the choice of some by. trait beings ent. For example, the result of the simulation is displayed on a screen. The system may include a library of coloring or gradient fading patterns on the hair and an interface for selecting in the library a model, the control unit. being arranged to control the device so as to reproduce on the wick the selected model. The system can be arranged to automatically prepare application elements such as sheets, on which is present the composition for producing the gradient. If, for example, the hairdresser indicates the number of locks he wants to make, the lengths of hair, and the system produces all application items ready for use. By "graded coloration or discoloration", it is necessary to include a coloration or discoloration of the hair delimited by at least two distinct color zones, the hair thus colored or discolored may have one or more colorimetric coordinates chosen from L, C *, h , a and b that are continuously between these two areas. It is therefore possible to obtain a gradient coloration or bleaching such that, between the two distinct color zones, the colored or bleached hair has a tint h varying from m. the era continues. It is also possible to obtain a gradual coloring or bleaching such that, between the two distinct color areas, the colored or bleached hair has a continuous clarity. More lightly, shades on the hair ranging from: - light or dark or winters according to a m -se tone, - from one tone to another at equivalent level of clarity, or - one of their combinations, can be considered as aesthetic. As detailed below, the variation of the color coordinate between the two areas may be regular or non-regular. The invention makes it possible to obtain a gradual coloring or discoloration of the hair, for example wicks, for example by creating a discoloration which starts from 2 tones in roots up to 4 tones or more towards the tips. For the record, the tones measure the clarity of the hair on a scale of 1 to 10, the value 1 corresponding to the black and the value 10 to the platinum blonde. The values 3, 5 and 7 correspond to a brown, a brown and a dark blond respectively. The gradation can be obtained by progressive discoloration of the hair, when progressing towards the root or towards the tip, the composition being a bleaching composition.

The gradual coloring or bleaching may be performed on all or part of the length of one or more locks of hair. Gradual staining or discoloration can, therefore, be performed on one or more locks of hair from the root to the tip of the treated hair. Preferably, the gradient extends to the root, though the gradients obtained by the methods of the invention may start at a location that is not necessarily root and end at another location that is not the tip. Gradients can be made on everything or p. e hair, and especially on one or more locks. Gradations of different aspects can be achieved depending on the location of the hair, and / or on the composition chosen. The composition may be present on a sheet member prior to being contacted with the hair and the sheet member is left in place during the action of the composition. In this case, the sheet element can act as a means of protection which reduces the risk of transfer to the other hair by forming a barrier between the treated hair and the other hair. The present invention also relates to a sheet element on which has been deposited with the aid of a device automatically controlled a deposit of composition whose property of coloring or discoloration of the hair y: e as a function of the position along the item in sheet. As mentioned above, the coloring or bleaching property which varies may be related to the application of a s ulus on the composition.

Stimulus The composition can be subjected to a stimulus that v. e, that is to say that the composition, deposited on the hair or on a different support, in particular an application element, or prior to its distribution by a device, or during this distribution, is subjected to a V. at least one direction of a magnitude characterizing the stimulus. The composition may be simultaneously subjected to a spatially inhomogeneous stimulus in a predefined manner so that some regions of the composition mass are more exposed than others to the stimulus. the coloring or bleaching properties of the composition. The composition may also be subject to a stimulus that varies over time depending on the exposed areas and / or that subjects certain areas to the stimulus longer than others. In this case, the mass of composition receives, over time, an exposure to the stimulus which varies according to its regions.

The stimulus may be bright, thermal, mechanical and / or creep, flow, pH or redox. The stimulus may be applied by a stimulus applicator having a light irradiator and / or a heater and / or a reservoir for containing the composition. The application of s. ulus can be done in situ or not. The stimulus application device is for example in the form of a handpiece or comprises a handpiece. In this case, the user can move the handpiece relative to the composition and thus, for example, more or less expose it to the stimulus according to the location, so as to locally modify its coloring or discoloration. The method may include the step of exposing the composition differently to the stimulus depending on the location, preferably so as to create a gradual change in its properties. In one exemplary embodiment, the composition is subjected to a nonzero temperature gradient. In this case, a first zone of a composition deposit can be brought to a first temperature while a second zone, distinct from the first, can be brought to a second temperature different from the first. The composition is then chosen to exhibit coloring or discolouring properties which vary with temperature, for example because of the use of a compound encapsulated in a wax or because of a modification of the composition. reaction kinetics. For example, the composition is deposited on a sheet element and comprises an alkaline agent, hydrogen peroxide and a powder of a wax encapsulated persalt whose melting temperature varies from 40 to 60 ° C. The application of a predefined temperature gradient at the sheet element may allow the encapsulated persalt to be released more or less from the wax and to obtain a deposit having a progressive hair bleaching power. , so as to obtain a gradient. As will be detailed hereinafter, the composition may initially be present in a reservoir of the applicator device of the ulus, which ensures its distribution, for example on the hair. In one embodiment, the semplating device may carry a first portion of the composition at a first temperature at a first zone to obtain a first fraction, which will be dispensed on the hair. The stimulus application device can then move relative to the treated hair and then wear a second one. e of the composition at a second temperature, different from the first, at a second zone of the hair, distinct from the first, in order to obtain a second fraction having a coloring or bleaching property different from the first fraction, and then ensure its distribution on the hair. A predefined law of temperature evolution can be applied automatically.

The first fraction can also be obtained by subjecting the composition to a first radiation having a first dominant wavelength and the second fraction can be obtained in the same way; the composition has a second radiation having a second dominant wavelength different from the first. These different wavelengths can induce one or more differentiated reactions within the composition, for example more or less catalyze a reaction, and cause coloring or bleaching properties that will vary. The evolution of the radiation can follow a predefined law and be carried out automatically.

The first fraction can be obtained by subjecting the composition to a first radiation during a first exposure period and the second fraction can be obtained by subjecting the composition to a second radiation during a second time. exposure time, different from the first one. In this case, the spectra of the first and second radiations can be distinct or identical.

The first fraction can be obtained by subjecting the composition to a first radiation having a first energy flux and the second fraction can be obtained by subjecting the composition to a second radiation having a second energy flux different from the first. The first fraction can be obtained by subjecting the composition to a first ray having an energy spectral density curve having a first width at half height for a given wavelength, and the second fraction can be obtained by subjecting the composition to a second ray having an energy spectral density curve having a second width at half height for that wavelength, the second width at mid-height being different from the first. The light and / or thermal stimulus may, for example, include ultraviolet radiation. In this case, the composition may be a photochromic composition, with no irreversible color change. Stimulus may be that the stimulus may be chemical and fractions having different properties may be produced by contacting said composition with a developer or inhibitor, especially an oxidizing or reducing agent, so that said composition is subjected to a non-zero gradient in the amount of material and / or exposure time of developer or inhibitor agent. if, one can obtain a mass of composition whose bleaching and coloring properties vary spatial ent.

When it is desired to perform oxidation dyeing, the developer may be an alkaline agent or a metal catalyst and the liquefying agent may be an acidic agent, a complexing agent, a developer disproportionation agent or a reducing agent. . The oxidizing agent may be hydrogen peroxide, an organic peroxide. such as benzoyl peroxide, a peracid such as peracetic acid, a halogen oxide, such as perborate, a persalt agent such as persilicate, perborate, or a peroxide metal salt such as potassium anganate. -. The developer or developer may be able to make the pH of the composition there. Indeed, an increase in pH may allow the bleaching power to be increased and a drop in pH may make it possible to reduce the discolouring power. The developer or bitumen agent may comprise a sensitizing agent or hair desensitizer, stream. a thiol. In this case, the method may comprise the steps of: applying along a lock of hair a sensitizing or desensitizing agent so that the amount of material of said agent, applied per unit area, varies so predefined when moving along said lock of hair, and - apply the composition at the level of said wick thus sensitized or desensitized, the mass of composition applied per unit area can v'er 'or be constant when l 'we move along the wick. Along the wick, the sensitizing or desensitizing agent may be applied with a volume amount y. but at a constant concentration or, in ante, at a constant volume quantity and at a viable concentration, or both. Device for Application of the Ulus or Composition The application device may comprise a system for guiding the hair and / or positioning relative to the head of the user. The guide system may be in the form of a clamp. The method according to the invention may comprise a step of determining the position of the applicator device relative to a surface on which the composition is intended to be applied or is applied. This facilitates the application of the stimulus or formulation that is locally suitable for obtaining the desired coloration or discoloration.

This surface may be defined by the hair on which the gradation of coloring or discoloration will be achieved or by an element of application. The positioning of the relativ application device can be determined from various m. 'Eras. In the case where the composition is present on a support other than the hair and then transferred to the hair, the support is, for example, movable in a controlled manner, relative to a stimulus application source or at an output through which the composition is dispensed, the position of the medium relative to the source of application to the stimulus or the output being known at all times by the device so as to locally apply the appropriate stimulus or formulation.

When the composition is already present on the hair during the application of the stimulus, the device can eg locate its position along the hair in p. .t t of the root or the tip. To determine the position in the space of the application device, an accelerometer can be used. The position in space can be deduced by double integration. The application device may be sensitive, in an embodiment of the invention, to its movement relative to the hair, which may allow it, knowing a reference point located for example at the root. hair, to know its positioning along the hair, this information being useful for modifying the applied stimulus or the formulation in order to obtain the desired coloration or discoloration.

The application device may comprise a device allowing, before the start or during the application operation, to initialize or reset the means for detecting the positioning of the application device. The application device may be in the form of a handpiece. By "handpiece" is meant a piece m. pulled by the user of a hand during the implementation of the method according to the invention. The handpiece may include a gripping portion and be connected or not to a base station. The method may comprise the successive steps of: introducing a first lock of hair into the guiding system of the application device, performing a gradation coloration or discoloration on said first lock by carrying out a method as described above, optionally apply to all or p. degrading coloration or discoloration carried out on said first wick means of protection for protecting said degraded coloration or discoloration against unwanted transfer, for example on other hair, then - disengaging said first lock of hair from the guide system and inserting a second lock of hair, - performing a gradual coloration or discoloration on said second lock by carrying out a method according to the invention. Alternatively, the method according to the invention can make it possible to perform a simultaneous treatment of a plurality of locks of hair. the method may comprise the steps of: - performing simultaneously a plurality of locks of hair coloring or discoloration gradient by implementing a method as described above, and - optionnell - ent, apply on all or part of the gradual colorations or discolorations made a protective means for protecting them mechanically. In this case, it is possible to use an application device comprising a comb defining a plurality of treatment spaces in which the locks to be treated are intended to be inserted. This comb has for example a shape - I adapted to the curvature of the skull, so as to facilitate the engagement of the locks inside, from the root. Such a method may therefore comprise, before performing the graded coloration or bleaching, a step of positioning in the guide system of the locks of hair to be treated. The application device can, moreover, be moved along the wicks to be treated during the realization of colorations or discolorations gradient, for example being integral with the aforementioned application device. Protection means which can be used in the context of the present invention will be described hereinafter. Order of the steps of applying and contacting the composition with the hair Before contacting the composition with the hair The exposure to the ulus or the deposition of the composition with a variable formulation may have place before bringing the composition into contact with the hair. In this case, the composition may be present on an applicator element, said applicator element possibly being in the form of a sheet element. The composition may, for example, be deposited on an application element, in particular a sheet element, and be subjected to a nonzero temperature gradient in order to obtain two fractions with different properties, and for example a variation. its coloring or fading properties. The non-zero temperature gradient can be obtained by a heating means present within the applicator element or by bringing a heating element closer to the deposition of the composition, said heating element not being connected to the application element. As mentioned above, the composition may be deposited on an applicator, especially a sheet mat, at a first region thereof. A step of contacting a developer or -better agent with said composition can be performed to obtain fractions having properties therein. ent. The method according to the invention may then comprise a step of contacting, for example by transfer, such a composition with the hair in order to obtain the coloring or gradual fading. After bringing the composition into contact with the hair The method according to the invention may comprise a step of bringing the composition into contact with the hair and then a step of exposure to a stimulus to change the properties of the composition of a composition. predefined way. The composition may, for example, be deposited on one or more locks of hair. In this case, the stimulus application device may include a hair guidance system. The method according to the invention may comprise the steps of: - engaging a first lock of hair in the guide system of the applicator of the ulus, - moving the applicator device of the ulus With respect to the lock of hair introduced, a predefined variation of the stimulus, for example the temperature along the wick or the intensity of exposure to radiation, is imposed on the composition in order to obtain the coloration or discoloration of the hair. degraded. Alternatively, the step of moving the stimulus application device may be accompanied by the delivery of a developer or inhibitor agent, this distribution taking place in a variable amount and / or with a variable concentration depending on the position of the stimulus application device along the treated lock of hair. I gmagi coloration, btenue The gradual coloration or discoloration of the hair obtained may comprise a first and a second region having between them a difference of AB color in the CIE Lab space greater than or equal to 1, not. - - ent to 3. Evolution of the color between the root and the points At least one colorimetric coordinate chosen from L, C *, a, b and h can evolve, continuously, notably linearly, when the along a lock of hair treated by a method according to the invention. In an exemplary embodiment, at least one of these colorimetric coordinates can evolve asymptotically, that is to say that by moving along a lock of hair treated by a method according to the invention to a given abscissa, said colorimetric coordinate y -e less and less per unit of distance. In other words, by moving along a lock of hair treated by a method according to the invention to a given abscissa, the derivative 10 of said color coordinate relative to the position along the wick is decreasing. By ex-t ple, in the three d cen ceneters before said abscissa, said color coordinate v. e more than 30% of what it varied in the three centimeters of a segment éloi ut of 6 cen 15 and 6 cm of said abscissa). Said abscissa can be in at least one of the following regions: the zone of the gradient closest to the hair root, the zone of the gradient closest to the tip of the hair, or a central zone. The achievement of an asymptotic gradient on the treated hair is preferential for aesthetic reasons. Preferably, an asymptotic gradient is produced with a colorimetric coordinate varying less and less per unit of distance as one moves towards a zone of the gradient close to the hair root. The gradients may or may not be adapted to the length of the lock depending on the locations of the hair. if the gradient obtained on a first wick may, for example, correspond, to a near homothety, to the gradient obtained on a second wick of a different length from the. first. The homothetic ratio may, in this case, - meters of said abscissa (between 9 30 correspond to the ratio of the length of the pr of the second wick - wick divided by the length Alternatively, one can obtain two identical gradients on two locks of hair of different lengths Means of protection A means of protection may be applied to any or all of the graded coloring or discolouration The means of protection may, for example, be in the form of A pulverulent composition, especially a fibrous composition, The average size of the particles constituting the pulverulent composition may be between 1 μm and 10 mm, more preferably 1 μm and 3 mm, preferably between 5 and 500 μm. is the half-population size of the population, referred to as D (0.5), the sheet element may comprise, in particular, a plastic material, in particular thermoplastic, a paper, a metal, especially aluminum, a woven fabric, a non-woven cellulose or one of its derivatives or poly. 6.6. The protection means may come into contact with the deposited composition deposit. The protective means may be immiscible with the composition to which it is applied. The protection means may be applied to a plurality of locks of hair each coated with a gradient color or discoloration. The protection means can be applied manually -8 ent. All or p. Hair with color or gradient fading may be wrapped by a sheet element. The protection means may, alternatively, be applied by means of an applicator, ie the applicator device of the ulus, the latter comprising in particular a system for guiding the hair and / or dispensing the composition intended for be covered by said protection means. The protective means may, once applied to the composition, an outer casing extending in all or p. e around the wick on which it is applied, said protection means defining flow t a tubular g e in which the wick is present. The protective means may be removed by washing, rinsing, rubbing and / or hair drying.

The invention can be better understood on reading the detailed description which follows, examples of implementation not li the ex in the drawing. exe, on which: tatives thereof, and - - Figure 1 schematically represents the achievement of a known staining 10 of the state of the art, - Figure 2 schematically represents the Gradient staining according to the invention - FIGS. 3A and 3B schematically illustrate the variation of colorimetric properties within the gradations according to the invention, FIGS. 4A and 4B schematically illustrate the variation of the stimuli applied. in order to obtain gradations according to the invention, FIGS. 5A and 5B show schematically different types of gradient stains obtained by implementing a method according to the invention, FIGS. 6 to 8 are block diagrams corresponding to various exemplary processing systems for carrying out the invention; FIG. 9A illustrates the distribution of the composition on an intermediate support; FIG. 9B illustrates the application of a stimulus on a mass of composition present on an intestinal support; FIG. 10 illustrates the application of the composition and / or a stimulus directly to the hair; FIG. 11 schematically represents, in perspective, a Example of a dispensing device arranged to be manipulated by the user and adapted to the practice of the invention; FIG. 12 illustrates different positions of the adjusting member and the corresponding passage sections; for the products to be mixed, Fig. 13 schematically shows a device with airbrushes, Fig. 14 shows an example of a control interface of the airbrush device, Fig. 15 shows schematically an example of a device. for treating a plurality of locks of hair simultaneously, - Figure 16 shows an alternative applicator device for performing a gradient, - Figure 17 is a diagram Electronic an ex ple of 10 control unit, and - Figure 18 is a device such pho controlled by the control unit for dispensing a composition with a formulation therein. 'Able. FIG. 1 schematically illustrates the obtaining, on a hair C, of wicks 700 of uniform color, using methods known from the state of the art. Such locks 700 may, as explained above, have an unnatural appearance at the roots 702. FIG. 2 schematically illustrates obtaining, on the hair C, wicks 701 in a gradient, for example whose hue varies along said rovings 701. Such rovings 701 are obtained by carrying out processes according to the invention. FIGS. 5A and 5B respectively show color gradients adapted to the length of the locks 701 and identical gradations regardless of the length of the locks 701. The gradients obtained in FIG. 5A correspond to a close homothety. Figures 3A and 3B illustrate the variation of colorimetric characteristics along a wick carrying a gradient according to the invention. As illustrated, this variation can be linear as a function of the position along the wick (curves in solid line) or nonlinear, no. asymptotic ent (dotted curves). A linear or asymptotic L (clarity) can be obtained along a wick treated by a method according to the invention as one moves along the wick from the root to the tip of the wicks. hair.

It is also possible to obtain, along a wick treated by a process according to the invention, a linear or asymptotic flow variation of C * (saturation) as one moves along the wick of the root towards the tip of the hair. It is also possible to obtain, along a wick treated by a method according to the invention, a variation, in particular linear or asymptotic, of a (position on the red / green axis) as one moves along the wick from the root to the tip of the hair or b (position on the blue / yellow axis) or h (hue). One or more of the colorimetric characteristics selected from: L, C *, h, a and b may vary as one moves along the treated lock of hair. It is possible to obtain a coloration, along a wick, which varies in "tones", the hair for example gayting at least one tone of discoloration. In the case where one wants to treat half or more of the hair, the gradient may advantageously follow a y. sigmoidal action (dashed line of FIG. 3B). The variation of the colorimetric characteristic of such a gradient is concentrated in the middle zone of the length of the hair and can make it possible to avoid the effects of roots and tips. It is possible, for example, to obtain a color at the root level that is relatively close to the visible root color before the process according to the invention is carried out. In p. you can obtain a color at the level of nuanced icines, especially ecl. 2 ton relative to the visible root color prior to implementation of the method according to the invention. For example, a color at the tips 25 significantly different from the color at the visible tips can be obtained before the process according to the invention is carried out. In particular, it is possible to obtain a color at the level of the tips nuanced, flow. It was brightened by 4 shades or more in relation to the color at the tips visible before the process according to the invention. FIGS. 4A and 4B show examples of the evolution of stimuli that can be applied along the lock of hair in the context of processes according to the invention based on the exposure to a color of the dyeing or decolouring composition. to modify its properties. One can, for example, have a v. lineage. The asymptotics of the temperature at 111 ° are subjected to the capillary composition as a function of the position along the wick. Alternatively, an amount of developer or inhibitor agent which e of m. linear or asymptotic era depending on the position along the wick. The application of such gradients may allow the obtaining of dyeing or bleaching powers of the hair in gradations, as detailed in the following. To automatically perform a gradient according to the invention, can be used a system 100 as shown in Figure 6, comprises two tanks 101 and 102 containing components to be mixed, a mixing device 103 perme. t to mix them in varying proportions, and a means 104 for acting in a predefined manner on the device to change during the t- ps the proportion in each of the components. Thus, it is possible to deliver a composition whose coloring or bleaching power varies during dispensing. The means 104 may simply vary for a predefined period the relative proportions of the components from the tanks 101 and 102, dependent on the user to manually control the rate at which the composition is distributed on the hair or on a support to control the spatial extent of the gradient and the degree of color change depending on the position. For example, for a distribution taking place during a predefined duration, if the user moves rapidly an output 106 of the mixing device, he can obtain a very extensive gradient spatially. If the speed of movement is not constant, it will be able to obtain for example, at the places where the speed is slow, a strong y: 'ation of the color per unit of distance and the placements where - the distribution was carried out with high speed, less variation per unit distance. The speed of variation may also, as illustrated in FIG. 7, be adjustable by the user, for example by means of a control unit 108 of the mixing device, provided with an interface 109 allowing the user to select some by . t beings, for example the duration of change of the formulation of the composition by the mixing device. Preferably, the ent ent unit 108 comprises a calculator which makes it possible to compute c-parameters of the process in order to obtain the desired gradient. For example, knowing the length of the gradient to be achieved, the speed of displacement of the outlet 106, it is possible to calculate the time during which the change in the formulation of the mixture must take place. The calculator can also determine what the variation in the formulation should be in order to obtain the gradient having the desired look, for example an asymptotic variation of the color as a function of the patch, as detailed. Previously, particularly with reference to Figure 3A or 3B. The processing system 100 may also include, as illustrated in FIG. 8 and detailed above, means for applying a stimulus to a composition mass in order to modify a coloring or bleaching property thereof. The system may comprise a device 110 for delivering the stimulus, this device being controlled for example by a trailing unit 111, which may or may not be connected to an interface 112. The composition C may be delivered on a support intermediate 150, illustrated in FIG. 9A, with a relative displacement of the support 150 and the output 106 delivering the composition, during the distribution thereof. This displacement can be known to the control unit, when it exists, which allows to take into account to deliver the mixture with the appropriate formulation at each location along the support 150. The displacement the output 106 25 relative to the support or invers ent may be motorized. The support 105 is for example striped and unwound at a controlled speed depending on the distribution of the mixture. FIG. 9B illustrates the possibility of having a mass of composition C already present on an intermediate support 150 and of locally modifying a coloring or bleaching property of the composition by means of a stimulus, so as to obtain a deposit of composition on the support, a coloring or bleaching property varies along it, in agreement with the gradient to be produced. In the confie. In Figure 9B, the stimulus is, for example, heat from a heater such as an infrared ray source. The heating member subjects the composition to a first temperature at a given placement and is then moved relative to the composition deposit to be in a new position. which it subjects the composition to a second temperature, different from the first. In there. However, the time of exposure to the heating member, brought to a constant temperature, varies, but the positioning time at a given location varies, so as to locally heat up the composition more or less. -without its thermal inertia. The composition can still be dispensed with a formulation y. directly on the hair, as shown in FIG. 10. In view, an ulus is applied to the composition in situ or when it is about to be applied to the hair, so as to obtain a predefined variation of a coloring or bleaching property along the hair, the device for applying the stimulus, for example in the form of a handpiece 3, arranged to receive the lock M of hair to be treated and for subjecting the composition to a treatment space, for example, a heat transfer device 3. The handpiece 3 may comprise, as illustrated, a handle 6 and a push-button for triggering a cycle. The stimulus can be applied non-uniformly when the handpiece 3 is moved along the wick to be treated M. For example, the power emitted by light-emitting diodes increases automatically. when the handpiece 3 e The handpiece position 3 relative to the treated wick M may advantageously be determined by a device for determining the positioning (not shown) of the handpiece. 3, for example an accelerometer, in order to control the energy emitted as a function of the position. The handpiece 3 may have various configurations for subjecting the composition to the stimulus. The handpiece 3 can comprise any means for receiving and guiding the hair, for example, as seen in FIG. 10, a groove 10 formed between an upper branch 12 and a lower branch 13, defining the treatment space . The branches 12 and 13 can be fixed relative to one another or alternatively be arranged so as to deviate in the manner of a clamp for example, to facilitate the establishment between them hair to treat. The feture of the branches can be detected in order to prevent the emission of the stimulus in case of failure of closure of the branches. The handpiece 3 may comprise means for determining the speed of movement of the wick M exposed to the stimulus relative to said handpiece. These means may comprise at least one rotary member rotating under the effect of the movement of the lock M in the treatment space in order to allow the processing system to calculate automatically according to this speed of displacement modification of the stimulus to be applied at the level of the composition.

The treatment system can be arranged in such a way as to be able to deposit the composition as the wick M is moved. The handpiece 3 may comprise for this purpose an applicator member 50 comprising, for example, a applicator pad for depositing the composition on the wick M. This applicator pad is carried by a support that does not interfere with the passage of the wick M between the branches 12 and 13. The v: "anon of power-dye or bleach hair The composition may also be obtained by subjecting it to visible or non-visible light, for example the composition may be a photochromic composition which is detectable under the effect of a given wavelength beam and the This gradient can be obtained by applying a light beam whose spectral-energy density near this wavelength increases automatically as one moves along the wick M. The app. The application of the ulus can also be performed without a handpiece, for example in the form of a cabin or a helmet in which the user is placed, the submission to the stimulus is effected at a distance, hair may possibly have been previously prepared for the trait ent, for example placed on a suitable support. Screen means may be provided on either side of the treatment space to oppose light leakage, for example a flexible seal, a row of bristles or a baffle. It is also possible to obtain a gradation on a lock M by bringing the hair into contact with a composition able to present a variation of its hair dyeing power by contact with an oxidizing agent. A nonuniform quantity of composition is for example applied to the wick M, the amount of composition deposited in the entant for example linear. when traveling. - from the root to the tip of the hair. This vation has been obtained automatically. In a second instance, the oxidizing agent is contacted with the composition deposition. During this step, the amount of oxidizing agent applied is for example cons. along the treated lock M. There could also be deposited a constant amount of composition along the wick M and a quantity v. of oxidizing agent along the wick M. The quantities y. Oxidation agent or composition compositions can be deposited along the wick M by transfer from an applicator element or by spraying, the output flow being automatically changed depending on the position along the wick. . The variable amount can be further applied by an applicator roll which is automatically and automatically exhausted in composition to be applied as it moves along the wick M. Alternatively, a constant amount of composition and a constant amount of oxidizing agent and make automatically determine the exposure time to the oxidizing agent according to the position at the wick M in order to obtain a gradient coloration or discoloration. It is also possible to carry out a gradual sensitization of the hair. A sensitizing composition is firstly applied to a lock of hair, for example by depositing a quantity of composition with a device which automatically varies the delivery rate as a function of the t ps, so that the quantity applied on the hair varies along the wick M. Thus, the degree of sensitization of the surface of the hair varies along this same direction. A coloring composition is then applied to the sensitized surface to obtain the gradient coloration or discoloration. In a variant, the stimulus application device comprises, within a reservoir, a composition intended to be applied to the hair. The stimulus application device comprises an applicator tip through which the composition is intended to be distributed over the lock of hair. A heater is present at the applicator tip. When the composition is present at the applicator tip, the composition is brought to a first temperature and dispensed at the wick. The stimulus application device is then moved relative to the wick and the heater is, in each case, brought to a distinct temperature, the temperature change taking place, for example, in a predefined manner. function of the gradient to obtain. A deposit is obtained on the wick having a hair coloring power which varies as one moves along the wick. The variation of the temperature is preferably continuous. In this example, it is possible to place the heating element With a device that distributes an oxidizing agent in controlled quantities, the composition having, in this case, a variation in its coloring power by contact with an oxidizing agent. FIG. 15 represents an applicator 800 allowing the simultaneous treatment of several locks M of hair. The applicator 800 comprises a support 801, which can in particular constitute a gripping part, connected to a comb comprising a. 811 to which is connected a plurality of teeth 812. Two consecutive teeth 812 define between them a treatment zone 820 in which all or part of a lock of hair is intended to be placed in order to receive the hair composition. The applicator 800 can comprise between 10 and 50 treatment zones 820, in particular between 20 and 40 treatment zones 820. The average molecular weight of the spacings e between two consecutive teeth 812 can be between 0.3 and 2 cm. preferably between 0.4 cm and 1.5 cm. The spacing between two consecutive teeth 812 corresponds to the length of the segment connecting the distal ends of two teeth 812.

The applicator 800 can make it possible to obtain a gradient coloration on a plurality of locks of hair. The applicator may comprise, at the level of the treatment spaces 820, dispensing orifices of the hair composition. The applicat 800 can ,. in addition, comprise a plurality of reservoirs (not shown) in which hair compositions having, for example, hair coloring powers of distinct hair are present. The applicator 800 may include a mixing device (not shown) to mix, in predefined proportions, two hair compositions from two separate reservoirs. The applicator 800 may be configured to apply an energy and / or chemical ulus as described above. The system of the invention may include, as illustrated in Figure 11, a body 160 defining two reservoirs and on which the user can press to distribute the contents. A dispensing head 161 ensures the mixing of the contents of the tanks in proportions y. 'Reliable. The tanks open with 15 examples by. apertures 162 and 163 opposite an adjustment piece having two outlets 164 and 165 may be more or less superimposed on the orifices of. This is a function of the position of this part relative to the body 160. Thus, for the three relative positions illustrated in FIG. 12, the distribution of the components in the proportions (expressed in%) is obtained 100/0, 50 / 50, 0/100. The part that acts on the flow rate in each of the components can be rotatable about the longitudinal axis of the device and automatically moved by an invisible elastic return member, which can be initially constrained by the user with a joystick 168. A brake, for example of the viscoelastic fluid type, can be rotated with the flow control part so that the displacement of the adjustment piece under the action of the elastic return member do not go too fast. To use the system illustrated in Figures 11 and 12, the user actuates the handle to constrain the elastic return member and releases. The adjusting part then moves automatically under the action of the return member for a predefined period, during which the user presses the reservoirs to force the products to pass through the dispensing head.

The formulation of the composition which is dispensed, which results from the mixing of the components in a cannula 169 provided with a mixer with controlled pitch propellers, for example. The user moves the cannula relative to the wick to be treated or to the intermediate support on which the composition is deposited, during the period of return of the adjustment piece to its initial position. He thus obtains a composition deposit whose coloring or bleaching property varies longitudinally. In Figure 13, there is shown a mixer device 180 with airbrushes, compo. t two airbrushes 181 and 182 converging, mounted on a frame. Each is fed by a dye tank 185 and a pressurized air supply. The product exit ports of the airbrushes are controlled by two motors 183 and 184 which by their movement will open or plug these orifices. The admission of pressurized air is also controlled electronically. A program controls the opening and closing of the orifices in a progressive manner and so that one opens while the other is closed. An interface is used to set certain parameters of the program, that is, the start and finish job levels, and the execution speed. The system allows a single instruction to return to the initial configuration. It may also include commands to invert the gradient, change the colors, shape the gradient, or spread the gradient over a larger or shorter length. The control unit, connected to the airbrush, is for example a microcomputer equipped with a co interface executing a software allowing, for example, airbrush engines and the user to choose cert 25 para. functional beings, such as the duration of evolution of the formulation of the mixture formed at the intersection of the emitted sprays. FIG. 16 shows a ent feed system for applying two components with variable proportions using applicator pads 190 and 191 which are pressed with respective varying forces on the surface to be treated, in order to deposit a quantity of each of the more or less large components. A pusher 192, automatically controlled, exerts a variable pressure on each of the applicator pads over time, so as to obtain the desired deposits. EXAMPLES EXAMPLE 1 The following assembly, corresponding to FIGS. 17 and 18, is carried out. A) First part called "stationary housing" The following parts are integrated in this first part: - A façade with 2 pushbuttons 201 and 202, and 1 liquid crystal display 203, connected by a serial link to a logic network 204. - An electronic card comprises the programmable logic array 204, its Eprom 205, an oscillator 206, for example at 24 I, a power module 207, a power supply, an on / off button 209. - A general power supply 208 The logic network progr. able is eg reference cyclone ifi EPC 3 from the company Altera and performs several functions: 1) the capture of the state of the two adjustment buttons 201 and 202. Each button advances, in increment. t, or by decreasing, an 8-bit register called tceesigne. 2) sending the liquid crystal display 203 the value of a register set. The sending is done by serial link in the form of ASCII code. 3) the logic network 204 is connected to the power module 207, integrated in the printed circuit, 11 consists of an operational amplifier and a stage with power transistors, which can generate currents of a few. fathers. This power module is capable of moving one printhead. - ft 4) a calculation and a comparison operation: As soon as the operator presses the on / off button, the network calculates a 16 bit register "deensigne" with doonsigne = t 255 ... consigAe. Then, it increments a 16-bit "claction" register from 0 to d. e. When it reaches a value, it incr ente an 8-bit Vaction register, increments an 8-bit "I" register and sets it to zero. It compares I with 16. As soon as I reaches 16, it waits 10 seconds with - # be all registers to zero.

During these calculation operations, the logical network directs the power module to impose a voltage of 1/8. fathers (from 0 to 2 A). The Cyclone HI is clocked by the oscillator at 24 and connected to the Eprom, which is for example reference EPCS16 of the company Altera. i, when powering on the device, the program that controls the actions of the logical network is referred from this Eprom to the logical network. u) Seeonee 7: -tie said "bnladable" A distribution head 220 is made as illustrated in Figure 18 comprising an electromagnet 221, powered by the aforesaid power module 207.

The head 220 is traversed by two flexible hoses 222 and 223, through which passes a fluid that can be pressurized. For example, the fluids are stored in flexible plastic compartments constituting first 225 and second tanks 226 and can be crushed by hand. The two hoses are held by a housing 230.

The electromagnet 221, when energized, pushes a compression bar 233 against at least one return spring 234. Thus, when the electromagnet is not energized, the pipe 222 is compressed and the pipe 223 is not compressed. The more the electromagnet is energized, the more the pipe 223 is compressed and the more the pipe 222 is released. The two pipes 222 and 223 open to the same outlet, embellished with a baffle mixing system. The unit consisting of the delivery head and the two reservoirs is attached at p. e of the system that can be moved by the user, also known as a handpiece. c) Operation The two reservoirs are filled with a first color and a second color, respectively. Turn on p. The Eprom informs the programmable logic network The user will choose, thanks to the two buttons 201 and 202, the value tC011Si e, corresponding to the length of the deletion he wants to make. A pressing of the on / off button 209, and compressing the two reservoirs 225 and 226, the user delivers the products, thereby moving the head along the paper. current delivered to the electromagnet v. e automatically during this movement, you that modifies the relative proportion of each of the products contained in the two tanks in the distributed mixture, so the coloring or bleaching property of the mixture. a wick to be treated in this paper that closes to trap the wick.He can thus achieve several wicks, or even the entire head.Whenever he wants to lengthen or shrink the length of the wick to achieve, he can redefine to Example 2 On the same frame, two airbrushes 181 and 182 converge. Each associates a dye reservoir 185, and a pressurized air supply. The product exit ports of the airbrushes are controlled by two motors 183 and 184 which by their movement will open or plug these orifices. The air pressure is also controlled electrically. A progr. It controls the opening and closing of the ports in a progressive manner so that one opens while the other closes. An interface is used to set certain parameters of the program, that is to say, the starting and ending service levels, and the speed of execution. The system allows for example a single instruction to return to the initial configuration. For example, two systems 185 of the system are introduced with reference to FIG. 13, respectively, a red color and a yellow color. The colorations are of direct coloring type. The hairdresser takes a wick by the tip with one hand, starts the progr. e which runs automatically as it moves the apparatus along the wick. It gradually changes from a red coloring to a yellow coloring and obtains a very regular gradation effect. Example 3 A device as described with reference to FIGS. 11 and 12 is used, which comprises an elastic return member which returns to its initial position after having been forced, at a predetermined speed, and a system for dispensing a mixture which The proportion in two components is modified as a function of the position of a setting piece displaced by the elastic return member. The user forces the elastic return member, and while it returns to its initial position, moves an outlet through which the mixture is distributed relative to the wick to be treated or to a support which will then be brought into contact with the wick to treat. He thus obtains a deposit of composition whose formulation and coloring property or elorante varies longitudinally. For example, the reservoirs are filled with two direct Symbio 6.60 and Symbio 7.23 colors and the mixture is applied to 10 white m. wicks - Comparative tests The tanks are filled with two bleaching compositions. The era provides a lightening of 2 tones. The second provides a lightening - of 4 tones. We treat 7 locks on the left, 7 locks on the right. To produce the left wicks, a linear gradient is applied to aluminum sheets (20 cm x 5 cm) with a small veil (20 cm x 1.5 cm). Then, the wicks are wrapped in the aluminum foils. To make the left locks, the second composition alone is applied to aluminum sheets (20 cm × 5 cm) having a small web (20 cm × 1.5 cm). Then, the wicks are wrapped in the aluminum foils. The set of locks is left 30 minutes. We see that the left side is much more natural. EXAMPLE 4 The same test as in Example 3 is carried out, with the difference that an asymptotic type gradient is produced on the left locks. We see that the left side is much more natural and even more aesthetic than the p. left of Example 3. Example 5 An entire head test is carried out. The same procedure is followed as in Example 3 except that a lightening formula (2 tones) is used as the first composition, and a black formula as the second composition. -t pr We compare on the left a sigmoid type gradient and on the right a linear gradient. We see that both give an aesthetic result, with a clear preference for the left side.

Non-illustrated variants of implementation of the invention may combine features from the various embodiments which have just been described. The phrase "with one" must be understood as being synonymous with "having at least one". The expression "understood between" must be understood as inclusive limits.

Claims (27)

REVENDICATIONS1. A method of treating hair, comprising the step CLAIMS. A method of treating hair, comprising the step of changing predefined at least one coloring or bleaching property of the hair of a composition, of m. to obtain, after contacting this composition with the hair, an evolution of said property of the composition along the hair, leading to obtaining a gradation of coloring or discoloration on the hair. 2. Method according to claim 1, the evolution being obtained automatically. 3. Method according to claim 1 or 2, wherein one acts automatically on a device perme. t mixing two components, the composition resulting from the mixing of these components, said variable property depending on the relative proportion of one component relative to the other. 4. A process according to any one of claims 1 to 3, the composition being dispensed with an evolution of said property directly on the hair. 5. Method according to any one of claims 1 to 3, the composition being present on an intermediate support before being applied to the hair. 6. Method according to any one of the preceding claims, wherein it acts automatically on an adjusting means modifying the formulation of the composition. 7. Process according to claim 6, in which the actuator is acted on by means of an electrically controlled element or by means of an organ whose displacement is purely mechanical. that, in particular a return spring. 8. Method according to one of claims 6 or 7, wherein is moved motorized outlet distributing the composition relative to the lock of hair or a support to be applied to the lock of hair, during the distribution of the composition . 9. Method according to one of claims 6 or 7, wherein is manually moved an outlet dispensing the composition relative to the lock of hair or a support to be applied to the lock of hair, during the distribution of the composition. 10. A method according to any one of the preceding claims, wherein the evolution of said property is auto-matically and the automatic control is performed after acquisition of at least one par. to be entered by the user, in particular a function of evolution along the lock of hair to be treated with at least one colorimetric characteristic of a graded coloration or discoloration to be obtained, and / or at least one geometrical characteristic a lock of hair to treat. 11. The method of claim 10, said evolution function being an ae or asymptotic function. 12. The method of claim 10 or 11, the automatic control effec. t according to a predefined evolution of the h tint and / or saturation C * of the gradient to be obtained. 13. Method according to any one of claims 10 to 12, the automatic control being effected according to the hue of at least one region delimiting the gradient to be obtained, no ent tint entered by the user. 14. Method according to any one of claims 10 to 13, the automatic control being effected according to the length of the gradient to obtain 20 and / or the length of the wick to be treated, including a gradient length and / or or a wick length entered by the user. The method of any one of claims 10 to 14, wherein the position of the device along the wick is detected and taken into account in the automatic control to change the property of the composition along the wick. 16. A method according to any one of claims 10 to 14, the automatic control being effected at least according to a value of a gradient colonel of the gradient to be obtained, no - ing a value entered by the user. 17. A method according to any one of the preceding claims, wherein the graded coloration or discoloration to be obtained comprises a first and a second region having between them a color difference AF, in the CIEL space a and b greater than or equal to 1 , no: ent to 3. 18. The method as claimed in any one of the preceding claims, further comprising a step of simulating the gradient to be obtained before carrying out said gradation on the hair. 19. System for obtaining a coloration or gradual bleaching on the hair, comprising a device, making it possible to obtain a composition having at least one property, coloring or bleaching hair that evolves in a predefined manner to obtain, after contacting the composition with at least one lock of hair, an evolution of said property of the composition along the lock of hair, leading to obtaining a color gradient or discoloration on this wick. 20. System according to claim 19, comprising a unit for controlling the device. 21. System according to claim 20, the control unit being connected to an interface for entering at least one par. according to which the device is controlled, flow a par. it is related to the appearance of the gradient to be made and / or to a characteristic of the wick to be treated. 22. The system of claim 20 or 21, the device comprises two tanks containing two components to be mixed and a mixer for mixing said components, the composition having a coloring or bleaching property varying according to the relative proportion of said compounds in the mixture, the device being arranged to allow the control unit to cause said proportion. 23. System according to any one of claims 19 to 22, being arranged to deliver the composition progressively, with a v ~ ation of a dyeing or bleaching property, along the wick. 24. System according to any one of claims 19 to 23, t arranged to deliver the composition on an intermediate support. "e before transfer to the hair. 25. System according to any one of claims 19 to 24, 30 comprising an airbrush for delivering the composition or a cannula, preferably equipped with a mixer. 26. System according to any one of claims 19 to 25, compo t a means of simulation of the coloration or gradual discoloration to obtain. 27. System according to any one of claims 20 to 26, 5 comprising a library of hair coloring or fading patterns on the hair and a p interface: J is to select in the library a model, the control unit being arranged to control the device so as to reproduce on the wick the selective pattern