Cosmetic application element

Abstract

The present invention relates to a cosmetic device comprising: a support and a composition, carried by the support, for dyeing or bleaching the hair, said composition having a formulation that varies depending on the position on the support, so as to allow shaded dyeing or bleaching to be produced on the hair by transfer.

Claims

1. A cosmetic device comprising: a support comprising a water-soluble material; and a composition, carried by the support, for dyeing or bleaching hair, said composition for dyeing or bleaching the hair having a formulation that varies depending on a position of the composition for dyeing or bleaching the hair on the support so as to allow shaded dyeing or bleaching to be produced on the hair by transfer, a dyeing or bleaching property of the composition for dyeing or bleaching the hair varying continuously along a dimension of the support and/or oxidizing or reducing power of the composition for dyeing or bleaching the hair varying continuously along a dimension of the support, wherein the support is configured to: vary colorimetric characteristics along a lock of treated hair when the support is brought into contact with the lock of hair, the varying being based on the variance in the oxidizing and/or reducing power of the composition for dyeing or bleaching the hair along a longitudinal axis of the support, and/or vary a quantity of the composition for dyeing or bleaching the hair deposited linearly along the longitudinal axis of the support such that colorimetric characteristics along a lock of treated hair vary when the support is brought into contact with the lock of hair.

2. The device according to claim 1, the support being in the form of a sheet element.

3. The device according to claim 1, the support comprising a housing in which the composition for dyeing or bleaching the hair is present.

4. The device according to claim 1, the composition for dyeing or bleaching the hair being in a set form on the support.

5. The device according to claim 1, a dyeing or bleaching property of the composition for dyeing or bleaching the hair varying continuously along the dimension of the support, by way of a linear or asymptotic variation.

6. The device according to claim 1, the support being elongate and the reducing or oxidizing power and/or colour of the composition for dyeing or bleaching the hair varying continuously along the longitudinal axis of the support.

7. The device according to claim 1, the support being designed to be closed around a lock to be treated.

8. A cosmetic assembly comprising: a device according to claim 1, and at least one of: an applicator, intended to collect all or part of said composition for dyeing or bleaching the hair and then to apply it to the hair, and/or a solvent for dissolving the composition for dyeing or bleaching the hair and thus ensuring its transfer onto the hair.

9. The cosmetic assembly according to claim 8, the applicator being a roller.

10. A cosmetic assembly comprising: a plurality of devices according to claim 1, which are designed for different lengths of locks and/or for producing different shadings.

11. A method for dyeing or bleaching the hair, comprising the steps of: bringing at least one lock of hair into contact with the composition for dyeing or bleaching the hair that comes from a device according to claim 1 in order to obtain shaded dyeing or bleaching of the hair.

12. The method according to claim 11, the composition for dyeing or bleaching the hair being brought directly into contact with the at least one lock of hair.

13. The method according to claim 12, said method comprising, after the composition for dyeing or bleaching the hair has been brought into contact with the at least one lock of hair, a step of bringing the support into contact with water or aqueous hydrogen peroxide solution in order to dissolve all or part of said support and to obtain the shaded dyeing or bleaching.

14. The method according to claim 11, wherein the composition for dyeing or bleaching the hair is brought into contact with a solvent configured to dissolve the composition for dyeing or bleaching the hair, the composition for dyeing or bleaching the hair being applied by transfer along the at least one lock of to the hair by contact with the solvent.

15. The method according to claim 14, the solvent being water or an aqueous hydrogen peroxide solution.

16. The method according to claim 11, comprising, after the composition for dyeing or bleaching the hair has been brought into contact with the at least one lock of hair, the step of closing the support around the at least one lock of hair.

17. The method according to claim 11, further comprising the steps of: collecting all or part of the composition for dyeing or bleaching the hair with an aid of an applicator before said composition for dyeing or bleaching the hair has been brought into contact with the at least one lock of hair, and bringing the composition for dyeing or bleaching the hair collected by the applicator into contact with the at least one lock of hair in order to obtain the shaded dyeing or bleaching of the hair.

18. A method for preparing a device according to claim 1, comprising the steps of: arranging the support, and depositing a precursor composition that has a shaded hair dyeing or bleaching power which can vary under an effect of a chemical and energy stimulus on said support, with an aid of an inkjet printer, an airbrush, or a hand-operated mixing device, and subjecting a quantity of the precursor composition to said stimulus in order to develop a dyeing or bleaching property depending on the position on the support, so as to form the composition for dyeing or bleaching the hair.

19. The method according to claim 18, the composition for dyeing or bleaching the hair being deposited and the stimulus being applied depending on a length of at least one lock to be treated.

20. A cosmetic device comprising: a support comprising a water-soluble material; and a composition, carried by the support, for dyeing or bleaching hair, said composition for dyeing or bleaching the hair having a formulation that varies depending on a position on the support, so as to allow shaded dyeing or bleaching to be produced on the hair by transfer, the variation in the formulation of the composition for dyeing or bleaching the hair making it possible to obtain shaded dyeing or bleaching along a lock of treated hair in a length direction of the lock, comprising first and second regions that have between each other a colour difference in the Commission Internationale de l'Eclairage Lab (CIELab) colour space of greater than or equal to 1, wherein the support is configured to: vary colorimetric characteristics along a lock of treated hair when the support is brought into contact with the lock of hair, the varying being based on the variance in oxidizing and/or reducing power of the composition for dyeing or bleaching the hair along a longitudinal axis of the support, and/or vary a quantity of the composition for dyeing or bleaching the hair deposited linearly along the longitudinal axis of the support such that colorimetric characteristics along a lock of treated hair vary when the support is brought into contact with the lock of hair.

21. A cosmetic device comprising: a support comprising a water-soluble material, and a composition, carried by the support, for dyeing or bleaching hair, said composition for dyeing or bleaching the hair having a formulation that varies along a dimension of the support, so as to allow progressive shaded dyeing or bleaching to be produced along a lock of treated hair by transfer, wherein the support is configured to: vary colorimetric characteristics of a lock of treated hair when the support is brought into contact with the lock of treated hair, the varying based on a variance in the reducing power, oxidizing power and/or color of the composition for dyeing or bleaching the hair along a longitudinal axis of the support, and/or vary a quantity of the composition for dyeing or bleaching the hair deposited linearly along a longitudinal axis of the support such that colorimetric characteristics along the lock of treated hair vary when the support is brought into contact with the lock of hair.

Description

DESCRIPTION OF THE FIGURES

(1) The invention may be better understood from reading the following detailed description of non-limiting implementation examples thereof and from examining the appended drawing, in which:

(2) FIG. 1 schematically shows the production of dyeing known from the prior art,

(3) FIG. 2 schematically shows the production of shaded dyeing according to the invention,

(4) FIGS. 3A and 3B schematically illustrate the variation in colorimetric characteristics within shadings according to the invention,

(5) FIGS. 4A and 4B schematically illustrate the variation in stimuli applied in order to obtain cosmetic devices according to the invention,

(6) FIGS. 5A and 5B schematically show various types of shaded dyeings obtained by implementing a method according to the invention,

(7) FIG. 6 schematically and partially shows a cosmetic device according to the invention,

(8) FIG. 6a shows a variant embodiment of the device from FIG. 6,

(9) FIG. 7 schematically and partially shows a variant cosmetic device according to the invention,

(10) FIG. 8 shows a section along VIII-VIII of the device from FIG. 7,

(11) FIGS. 9 to 14 show exemplary embodiments of methods according to the invention,

(12) FIG. 15 schematically and partially shows a result obtained from the methods described in FIGS. 9 to 14,

(13) FIG. 16 shows an example of an assembly according to the invention,

(14) FIGS. 17 to 28 show examples of methods for preparing devices according to the invention,

(15) FIG. 29 schematically shows a perspective view of an example of a dispensing device designed to deposit a composition that has a shaded hair dyeing or bleaching power,

(16) FIG. 30 illustrates various positions of the adjusting member of the device from FIG. 29 and the sections of corresponding passages for the products intended to be mixed,

(17) FIG. 31 is an electronic diagram of an example of a control unit, and

(18) FIG. 32 is an example of a device controlled by the control unit for dispensing a composition having a variable formulation.

(19) In the drawing, the actual relative proportions have not always been respected, for the sake of clarity.

(20) FIG. 1 schematically illustrates the production, on a head of hair C, of locks 700 having a uniform colour by the implementation of methods known from the prior art. Such locks 700 may, as explained below, have a rather unnatural appearance at the roots 702.

(21) FIG. 2 schematically illustrates the production, on the head of hair C, of shaded locks 701, for example where the tint varies along said locks 701. Such locks 701 are obtained by implementing methods according to the invention.

(22) FIGS. 5A and 5B respectively illustrate colour shadings adapted to the length of the locks 701 and shadings that are identical whatever the length of the locks 701. The shadings obtained in FIG. 5A correspond, give or take one homothetic transformation.

(23) FIGS. 3A and 3B illustrate the variation in colorimetric characteristics along a lock bearing a shading obtained by virtue of the cosmetic devices according to the invention.

(24) As illustrated, this variation can be linear depending on the position along the lock (solid-line curves) or non-linear, in particular asymptotic (dashed lines).

(25) It is possible to obtain, along a lock treated by a method according to the invention, a linear or asymptotic variation of L (clarity) on moving along the lock from the root towards the tip of the hairs.

(26) It is also possible to obtain, along a lock treated by a method according to the invention, an in particular linear or asymptotic variation of C* (saturation) on moving along the lock from the root towards the tip of the hairs.

(27) It is furthermore possible to obtain, along a lock treated by a method according to the invention, an in particular linear or asymptotic variation of a (position on the red/green axis) on moving along the lock from the root towards the tip of the hairs, or of b (position on the blue/yellow axis) or of h (tint).

(28) One or more colorimetric characteristics chosen from; L, C*, h, a and b may thus vary along the lock of hair treated.

(29) It is possible to obtain dyeing, along a lock, which varies in “tones”, the hairs receiving for example at least one bleaching tone.

(30) When it is desired to treat half or more of the hairs, the shading can advantageously follow a sigmoid variation (dashed curve in FIG. 3B).

(31) The variation in the colorimetric characteristic of such a shading is concentrated in the mid-region of the length of the hairs and can make it possible to avoid the effects of roots and tips.

(32) It is possible, for example, to obtain a colour in the region of the roots that is relatively close to the colour visible at the roots before the method according to the invention is implemented. In particular, it is possible to obtain a colour in the region of the roots that is nuanced, in particular lightened, by 2 tones with respect to the colour visible at the roots before the method according to the invention is implemented.

(33) It is possible, for example, to obtain a colour in the region of the tips that is significantly different from the colour visible at the tips before the method according to the invention is implemented. In particular, it is possible to obtain a colour in the region of the tips that is nuanced, in particular lightened, by 4 tones or more with respect to the colour visible at the tips before the method according to the invention is implemented.

(34) The production of the desired variation in the dyeing or bleaching property of the composition on the support depending on the position on the support depends on the way in which the composition acts on the hair in order to dye or bleach it. A dyeing or bleaching property of the composition 10 may vary continuously depending on the position on the support 2, in particular by way of a linear or asymptotic variation.

(35) In the case for example in which the composition comprises a colourant, the quantity of colourant can vary along the support, decreasing towards one end. In the case of two colourants, the quantity of one of the colourants can decrease towards one end of the support while the quantity of the other colourant decreases towards the other end of the support. The decrease can be linear or non-linear, depending on whether the shading desired is asymptotic, in particular sigmoid, shading or linear shading.

(36) In the case in which the composition was obtained with the aid of a precursor exposed to a stimulus, the development of the latter makes it possible to control the development of the dyeing or bleaching property of the composition.

(37) FIGS. 4A and 4B show examples of the development of the stimuli applied along the support in the context of methods for preparing cosmetic devices according to the invention that are based on the application of a stimulus.

(38) It is possible, for example, to have a linear or asymptotic variation in the temperature to which the precursor composition is subjected depending on the position along the support.

(39) Alternatively, it is possible to deposit a quantity of developer or inhibitor which varies in a linear or asymptotic manner depending on the position along the support.

(40) The application of such gradients can allow shaded hair dyeing or bleaching powers to be obtained, as described in detail below.

(41) FIG. 6 shows an example of a cosmetic device 1 according to the invention. This device 1 comprises a support 2 in the form of a sheet-like element, on which there is present a deposit of dyeing or bleaching composition 10. The deposit of composition 10 may be fixed to the support by way of a deposit of an adhesive composition, extends along a longitudinal axis Y and has a shaded hair dyeing or bleaching power. In the variant illustrated, the axis Y also corresponds to the longitudinal axis of the support 2.

(42) The variant illustrated in FIG. 6a shows an exemplary embodiment in which the deposit of composition 10 extends along the longitudinal axis Y from a first end 30a to a second end 30b of the support 2.

(43) FIGS. 7 and 8 show a variant embodiment in which the cosmetic device 1 comprises a support 2 comprising a housing 3 in which the composition 10 is present. In this exemplary embodiment, the composition 10 is preferably in a set form, in particular in the form of a gel.

(44) In the examples illustrated, at least one colorimetric coordinate of the deposit of composition 10 varies continuously depending on the position on the support 2. For example, the tint of the composition 10 varies continuously along the longitudinal axis Y of the support 2.

(45) Alternatively, the oxidizing or reducing power of the composition 10 varies continuously depending on the position on the support 2.

(46) The support 2 may be elongate and the reducing or oxidizing power and/or the colour of the composition 10 may vary continuously along the longitudinal axis Y of the support 2.

(47) FIG. 9 illustrates the transfer of the composition 10 present on the device 1 onto a lock M of hair. In this example, the device 1 is moved towards the lock M to be treated and the composition 10 carried by the support 2 is brought directly into contact with the hairs to be treated. In this case, it is possible, before contact is made with the lock M to be treated, to bring the composition 10 into contact with a solvent, preferably water or aqueous hydrogen peroxide solution, for dissolving it and transferring it onto the lock M.

(48) FIG. 10 illustrates the collecting of the composition on the device 1 from FIGS. 7 and 8 by virtue of an applicator 20 that has a roller 22 which the user rolls, as a first step, on the composition 10. The applicator comprises a gripping part 21.

(49) The roller 20 is then moved along the lock M in order to deposit the composition 10 thereon and to obtain the shaded dyeing or bleaching, as illustrated in FIG. 11.

(50) FIGS. 12 and 13 show an exemplary embodiment in which the device 1 is moved towards the lock M to be treated in order to bring the composition 10 into contact with the hair. The support 2 is then folded over itself so as to form a tubular sheath G. The support 2 may comprise at a first end 30a an adhesive deposit 31 for fixing the first end 30a to a second end 30b so as to form the sheath G. The sheath G can advantageously limit the risks of transferring the composition 10 onto untreated locks.

(51) FIG. 14 shows an exemplary embodiment in which the support 2 is water-soluble. A tubular sheath G has for example been formed in the same way as in FIG. 13. However, in this example, a step of bringing the support 2 into contact with aqueous hydrogen peroxide solution is carried out in order to eliminate said support and obtain the shaded dyeing or bleaching.

(52) FIG. 15 illustrates a deposit of composition 10 obtained by the methods illustrated in FIGS. 9 to 14 and allowing shaded dyeing or bleaching to be obtained on the hair.

(53) FIG. 16 shows an example of an assembly 50 according to the invention, comprising a device 1 according to the invention and an applicator 20 intended to collect all or part of the composition 10 present on said device 1.

(54) Various methods for preparing the device 1 according to the invention will now be described.

(55) FIGS. 17 to 19 illustrate a method for preparing a cosmetic device 1 according to the invention by bringing a precursor composition 100, the hair dyeing power of which can vary, into contact with an oxidizing agent 110.

(56) As shown in FIG. 17, a non-uniform quantity of composition 100 has been applied to the support 2, the quantity of composition 100 deposited increasing for example linearly along the longitudinal axis of the support.

(57) In a second step, the oxidizing agent 110 is brought into contact with the deposit of composition 100. During this step, which is illustrated in FIG. 18, the quantity of oxidizing agent 110 applied is constant along the longitudinal axis of the support 2.

(58) In these exemplary embodiments, the thicknesses of the deposits of oxidizing agent 110 and composition 100 have been exaggerated for the sake of clarity of the drawing.

(59) It may be possible to deposit a variable quantity of oxidizing agent 110 along the longitudinal axis of the support 2. It may also be possible to deposit a constant quantity of composition 100 along the longitudinal axis of the support 2 and a variable quantity of oxidizing agent 110 along the longitudinal axis of the support 2.

(60) The variable quantities of oxidizing agent 110 or of composition 100 can be deposited along the longitudinal axis of the support 2 by being transferred from an applicator element or by spraying, the outlet flow rate being modified depending on the position on the support 2. The variable quantity can also be applied by an applicator roller which uses up composition to be applied as it moves along the longitudinal axis of the support 2.

(61) Alternatively, it is possible to apply a constant quantity of composition 100 and a constant quantity of oxidizing agent 110 and to vary the exposure time depending on the position on the support 2 in order to obtain a shaded dyeing or bleaching power.

(62) Alternatively, it is possible to first of all apply the oxidizing agent 110 to the support 2 and then apply the composition 100. Of course, the embodiments described above apply mutatis mutandis to this variant.

(63) FIG. 19 illustrates the production of a cosmetic device 1 according to the invention, comprising a deposit of composition 10 having a shaded hair dyeing or bleaching power.

(64) FIGS. 20 and 21 illustrate another exemplary embodiment of a method for preparing a cosmetic device 1 according to the invention.

(65) A deposit of precursor composition 600, the hair dyeing power of which can vary depending on the temperature, is present on a support 2 as illustrated in FIG. 20.

(66) Furthermore, the support 2 comprises heating means (not shown) for obtaining a non-zero temperature gradient in at least one direction.

(67) FIG. 21 shows the production of a deposit of composition 10 after the temperature gradient has been applied to the support. Preferably, the dyeing and bleaching power varies continuously along the axis Y.

(68) As a variant, FIGS. 22 and 23 illustrate the production of a deposit of composition 10 by applying a non-zero temperature gradient by virtue of an external heating member 500.

(69) In the configuration in FIG. 22, the heating member 500 subjects the composition 600 to a first temperature. The heating member 500 is then moved with respect to the deposit of composition 600 in order to be moved into the position illustrated in FIG. 23, in which it subjects the composition 600 to a second temperature which is different from the first. In the meantime, it has subjected the composition to intermediate temperatures. Alternatively, the time of exposure to the heating member, brought to a constant temperature, varies but the length of time for positioning at a given position varies, so as to locally heat the composition to a greater or lesser degree, taking its thermal inertia into account.

(70) FIG. 24 shows a sheet-like element comprising a support 2 that can be folded along the axis X.

(71) In a first region 401, the support comprises a deposit of composition 100 and in a second region 402 it comprises a deposit of an oxidizing agent 110.

(72) The quantities of composition 100 and of oxidizing agent 110 can vary or be constant depending on the position in the first or second regions 401 and 402 along the axis X.

(73) FIG. 25 shows the step of folding the support 2 around the axis X that leads to the composition 100 being brought into contact with the oxidizing agent 110. The result of this bringing into contact is illustrated in FIG. 26, where a deposit of composition 10 is obtained.

(74) FIGS. 27 and 28 show a variant in which a device 300 for applying the stimulus comprises, within a reservoir delimited by a wall 301, a composition 600 intended to be applied to a support 2. The device for applying the stimulus comprises an applicator nozzle 302 through which the composition 600 is intended to be dispensed onto the support 2. In the example illustrated in FIG. 27, a heating member 303 is present in the region of the applicator nozzle 302.

(75) When the composition 600 is present in the region of the applicator nozzle 302, the composition is brought to a first temperature that allows a fraction 1000 of composition having a first dyeing power to be obtained, as shown in FIG. 27. This fraction is then dispensed onto the support 2.

(76) The device 300 for applying the stimulus is then moved in relation to the support 2 and can repeat various dispensing operations, the heating member 303, each time, being brought to a different temperature.

(77) Following a number of dispensing operations, a deposit of composition 10 having a hair dyeing power that varies along the support 2 is obtained on the lock M. The temperature is varied preferably continuously.

(78) It is possible in this exemplary embodiment to replace the heating member 303 with a device for dispensing an oxidizing agent in controlled quantities, the composition having, in this case, a variable dyeing power by being brought into contact with an oxidizing agent.

(79) The variation in the hair dyeing or bleaching power of the composition can be obtained by subjecting it to radiation.

(80) For example, the composition may be a photochromic composition that is revealable under the effect of radiation having a given wavelength and the shading can be obtained by applying light radiation the spectral energy density of which close to this wavelength increases along the support 2.

(81) FIG. 29 shows an example of a hand-operated device 170 for preparing and dispensing a composition that has a shaded dyeing or bleaching power. The body 160 defines two reservoirs and the user can apply pressure thereto in order to dispense the contents. A dispensing head 161 mixes the contents of the reservoirs in variable proportions. The reservoirs open for example through supply orifices 162 and 163 opposite an adjusting part that has two outlet orifices 164 and 165 that can be superposed more or less on the supply orifices depending on the position of this part with respect to the body 160. Thus, for the three relative positions illustrated in FIG. 30, the components are dispensed respectively in the proportions (expressed in %) of 100/0, 50/50, 0/100. The part which acts on the flow rate in each of the components may be able to rotate about the longitudinal axis of the device and may, if need be, be moved automatically by an elastic return member which cannot be seen and which can be stressed initially by the user by virtue of an operating handle 168. Alternatively, the operating handle 168 controls the position of the adjusting member and is actuated by the user during dispensing in order to vary the formulation of the mixture.

(82) In the presence of an elastic return member, a brake, for example of the viscoelastic fluid type, can be rotated with the part for adjusting the flow rate such that the movement of the adjusting part under the action of the elastic return member does not occur too quickly.

(83) In order to use the system illustrated in FIGS. 29 and 30, the user actuates the operating handle 168 in order to stress the elastic return member and then releases it. The adjusting part then moves automatically under the action of the return member for a predefined length of time, during which the user applies pressure to the reservoirs in order to force the products to pass through the dispensing head. Alternatively, in the absence of an elastic return member, the user moves the operating handle 168 in order to change the formulation.

(84) The formulation of the composition which is dispensed varies, said formulation resulting from the mixing of the components in a cannula 169 provided with a mixer for example having propellers that have opposite pitches. The user moves the cannula in relation to the intermediate support on which the composition is deposited. In this way, he obtains a deposit of composition, the dyeing or bleaching property of which varies longitudinally.

EXAMPLES

Example 1

(85) The following assembly is carried out, corresponding to FIGS. 31 and 32.

(86) a) First Part Called the “Fixed Casing”

(87) The following elements are incorporated into this first part: A façade carrying 2 push buttons 201 and 202 and 1 liquid crystal display 203, which are connected to a logic network 204 by a serial link. A printed circuit board comprising the programmable logic network 204, its Eprom 205, a, for example, 24 MHz oscillator 206, a power module 207, a power supply, an on/off button 209. A general power supply 208.

(88) The programmable logic network has for example the reference Cyclone III EPC 3 from Altera and carries out a number of functions:

(89) 1) sensing the state of the 2 adjusting buttons 201 and 202. Each button advances, either by incremental or decremental step changes, an 8 bit register called t.sub.setpoint.

(90) 2) sending to the liquid crystal display 203 the value of a register t.sub.setpoint. Sending is carried out by a serial link in the form of ASCII code.

(91) 3) the logic network 204 is connected to the power module 207 integrated into the printed circuit. It consists of an operational amplifier and a power transistor stage that can generate currents of several amps. This power module is capable of setting a print head into motion.

(92) 4) a calculation and a comparison operation:

(93) As soon as the operator presses the on/off button, the network calculates a 16 bit register “d.sub.setpoint” where d.sub.setpoint=255.Math.t.sub.setpoint. Next, he incrementally advances a 16 bit register “d.sub.action” from 0 to d.sub.setpoint. When he reaches d.sub.setpoint he incrementally advances an 8 bit register V.sub.action, incrementally advances an 8 bit register “I” and resets d.sub.action to 0. He compares I with 16. As soon as I reaches 16, he waits for 10 seconds before resetting all the registers to zero.

(94) During these calculation operations, the logic network instructs the power module to impose a voltage of I/8 amps (from 0 to 2 A). The Cyclone III is clocked by the 24 MHz oscillator and connected to the Eprom, which has for example the reference EPCS16 from Altera. Thus, when power is applied to the apparatus, the program which controls the actions of the logic network is transferred from this Eprom to the logic network.

(95) b) Second “Slidable” Part

(96) A dispensing head 220 as illustrated in FIG. 32 is produced, comprising an electromagnet 221 supplied by the abovementioned power module 207.

(97) Through the head 220 there pass two flexible tubes 222 and 223, through which there passes a fluid that can be pressurized. For example, the fluids are stored in compartments made of flexible plastic that form the first reservoir 225 and second reservoir 226 and can be squeezed by hand. The two flexible tubes are held by a case 230.

(98) When it is powered, the electromagnet 221 pushes a compression bar 233 against at least one return spring 234. Thus, when the electromagnet is not powered, the tube 222 is compressed and the tube 223 is not compressed. The more power is supplied to the electromagnet, the more the tube 223 is compressed and the more the tube 222 is released. The two tubes 222 and 223 open towards one and the same outlet, supplemented by a baffle mixing system. The assembly formed by the delivery head and the two reservoirs belongs to the part of the system that can be moved by the user, also known as hand piece.

(99) c) Operation

(100) The two reservoirs are filled respectively with a first colourant and a second colourant.

(101) Power is applied to the fixed part. The Eprom informs the programmable logic network. By virtue of the two buttons 201 and 202, the user will choose the value t.sub.setpoint corresponding to the length of shading he wishes to make.

(102) He moves the hand piece towards a support formed by a sheet of paper. By pressing the on/off button 209 and by compressing the two reservoirs 225 and 226, the user delivers the products. In doing so, he moves the head along the paper. The current supplied to the electromagnet varies automatically during this movement, thereby modifying the relative proportion of each of the products contained in the two reservoirs in the mixture dispensed, and thus the dyeing or bleaching property of the mixture.

(103) Next, the user places a lock to be treated in this paper, which he closes in order to enclose the lock. He can thus produce a number of locks, or even the entire head. Each time he wishes to lengthen or shorten the length of the lock to be produced, he can redefine t.sub.setpoint.

Example 2

(104) Use is made of a device as described with reference to FIGS. 29 and 30, which comprises or does not comprise an elastic return member which returns to its initial position after it has been stressed, at a predefined speed, and a system for dispensing a mixture which modifies the proportion of two components depending on the position of an adjusting part moved by the elastic return member.

(105) The user stresses the elastic return member, then, while the latter returns to its initial position, moves an outlet through which the mixture is dispensed in relation to a support which will then be brought into contact with the lock to be treated. Alternatively, he moves the operating handle 168 for the duration of dispensing. In this way, he obtains a deposit of composition, the formulation and the dyeing or bleaching property of which vary longitudinally.

(106) The reservoirs are filled with two bleaching compositions. The first ensures lightening by 2 tones. The second ensures lightening by 4 tones. There are treated 7 locks on the left and 7 on the right.

(107) In order to produce the left-hand locks, a linear shading is applied to aluminium foils (20 cm×5 cm) comprising a small web (20 cm×1.5 cm). Next, the locks are wrapped in the aluminium foils.

(108) In order to produce the left-hand locks, only the second composition is applied to aluminium foils (20 cm×5 cm) comprising a small web (20 cm×1.5 cm). Next, the locks are wrapped in the aluminium foils.

(109) All of the locks are left for 30 min.

(110) It can be seen that the left-hand part has a much more natural appearance.

Example 3

(111) The same trial as in Example 2 is carried out, except that an asymptotic shading is produced on the left-hand locks.

(112) It can be seen that the left-hand part is much more natural and even more attractive than the left-hand part in Example 2.

(113) Variants, which are not illustrated, of the implementation of the invention can combine characteristics from the various exemplary embodiments that have just been described.

(114) The expression “comprising a” should be understood to be synonymous with “comprising at least one”.

(115) The term “between” should be understood as including the limits.