EP4599733A1

EP4599733A1 - An applicator for applying treatment liquid to the hair, and a hair curler using the applicator

Info

Publication number: EP4599733A1
Application number: EP24168365.5A
Authority: EP
Inventors: Mark Johannes Lelieveld; Sze Keung LEUNG; Wai Ho LI
Original assignee: Koninklijke Philips NV
Current assignee: Koninklijke Philips NV
Priority date: 2024-02-08
Filing date: 2024-04-04
Publication date: 2025-08-13

Abstract

An applicator comprises a roller arrangement having at least one roller, wherein the roller comprises a central reservoir and a porous outer layer for transferring treatment liquid from the central reservoir to hair, wherein the roller is freely rotatable in use. The applicator is for example part of a hair curler which has a tubular heating barrel with a tubular sleeve around the heating barrel. The applicator functions as a treatment liquid application system, and one or more rollers are located along a path of the hair during winding on the tubular heating barrel and/or during removal of the hair from the hair curler. Thus, a protection topical may be applied before curling, a topical may be applied after curling, or both. The hair curler can for example apply treatment liquids before and after curling, and in an automatic way during use of the hair curler.

Description

FIELD OF THE INVENTION

This invention relates the application of treatment liquids to the hair, for example as part of a hair curling function. For example, it relates to hair curlers in which hair is wound around a heated drum and liquid is applied to the hair as part of the curling process.

BACKGROUND OF THE INVENTION

A hair curler is a handheld electronic product used to curl the hair.
Hair may be curled using dry heat, or by using steam. This invention relates to the application of a treatment liquid to the hair, for example as part of a curler which uses dry heat.
The main components of this type of hair curler are a handle, a heating element and a sleeve around the heating element to form a hair receiving space (referred to below as a "curling space"). The heating element is in the form of a heating barrel which generally has a cylindrical shape. The heating barrel is for example a tourmaline ceramic panel. Hair is wound around the heating barrel in use and is then heated to form a curl. Different sections of hair are treated in succession to create a desired style.
It is known to provide this type of curler with a water reservoir and a water spray system, for spraying water into the hair receiving space. Cold water may be used to prevent scolding, and topicals may also be applied to the hair by means of a spray function during curling.
The spraying operation is not efficient as it results in wastage, and it may also not result in a uniform application of treatment liquid to the hair. There is therefore a need for an improved treatment liquid application system for a hair curler.

SUMMARY OF THE INVENTION

The invention is defined by the claims.
According to examples in accordance with an aspect of the invention, there is provided an applicator for applying a treatment liquid to the hair, comprising:
a roller arrangement comprising at least one roller, wherein the roller comprises a central reservoir and a porous outer layer for transferring treatment liquid from the central reservoir to the hair, wherein the roller is freely rotatable in use.
The invention thus provides an applicator that can be used as part of a hair care device, for applying treatment liquid to the hair. The applicator is compact by having a central reservoir which delivers liquid to an outer layer. The free rotation of the roller means the whole surface of the roller is used to deliver liquid, giving a uniform application of liquid in use. For example, the roller rotates as a result of the passage of hair over the roller in use.
The central reservoir for example has a perforated outer wall which interfaces with the porous outer layer.
In one example, the central reservoir has first and second perforated outer walls arranged concentrically with respect to each other, and rotatable relative to each other between a sealed configuration and a liquid release configuration. The perforation holes align in the liquid release configuration but are misaligned in the sealed configuration.
In another example, the central reservoir has a perforated wall, and the applicator further comprises a closing member for opening and closing the perforations of the perforated outer wall, wherein the closing member is movable between open and closed states.
In this design a closing member is used to close openings in main perforated wall. The closing member for example comprises projections which extend though the perforations and the applicator further comprises a pusher for pushing against the projections.
The invention also provides a hair curler, comprising:

a tubular heating barrel around which hair is to be wound for curling;
a tubular sleeve around the heating barrel, wherein the sleeve has a longitudinal entry slit for receiving hair to be wound on the tubular heating barrel; and
the applicator as defined above, wherein the roller is configured to be located along a path of the hair during winding on the tubular heating barrel and/or along a path of the hair during removal of the hair from the hair curler.

This hair curler uses the roller as defined above to apply a liquid to the hair while it is being wound around the heating drum and/or when it is removed from the heating drum. This enables the liquid to be applied just before curling and/or after curling. The use of a roller with a liquid-retaining porous outer layer, which delivers liquid by means of contact with the surface, reduces waste and enables application of liquid to an accurate location.
The treatment liquid is for example for heat protection. This may simply comprise water, or it may comprise treatment topicals. The heat protection liquid is applied before curling. The treatment liquid may instead or as well comprise an after-care liquid or a fixation liquid. This maybe applied during or after curling. Both types of treatment liquid may be applied, at different times.
The entry slit for example has a U-shape or V-shape with lateral arms and a base, and wherein the roller is provided along at least one arm of the U-shape or V-shape. The hair enters the curling space through the entry slit so that it is moved along the surface of the roller arrangement during winding of hair into the curler.
Rollers may be provided at least along both arms of the U-shape or V-shape. There may be two or more rollers forming the roller arrangement.
A roller may instead or additionally be provided on the outside of the tubular heating barrel, e.g., along its length. Thus, as hair is wound around the heating barrel, it contacts the roller.
The hair curler may further comprise a looper for looping hair around the heating barrel, and a roller is provided on the looper.
The examples above relate to different rollers to apply liquid during winding of hair onto the heating barrel.
For applying liquid when removing hair from the hair curler, a roller may be located at the top of the tubular heating barrel. The entry slit is open at a distal end of the tubular sleeve, and hair is removed by sliding longitudinally off the heating barrel. Thus, when hair is removed from the curling space, it passes the top of the heating barrel, where a roller is, in this example, located.
The treatment liquid, for application after the curling, may comprise an after-care or fixation liquid as mentioned above.
When the roller arrangement includes rollers located along a path of the hair both during winding of hair onto the heating barrel and during removal of the hair from the hair curler, the hair curler then has at least two rollers. They are located such that the first roller (or rollers) applies liquid to the hair when it enters the curling space between the sleeve and heating barrel, and the second roller (or rollers) applies liquid to the hair when it is removed from the curling space. Thus, a full hair treatment, before and after curling, is automatically applied as part of the curling process.
In one example, the central reservoir comprises a cylindrical body with a recess at each end, and the hair curler comprises axles housed within the recesses. The roller is removable from the axles for replacement or replenishment.
In another example, the central reservoir comprises a cylindrical body with a projecting pin at one end extending along an axis of rotation and a centering recess at the other end.
Thus, there are different ways to mount the roller for free rotation, using pin and slot type bearings. Of course, any suitable rotational mounting may be used.
The heating barrel may have an adjustable size. This enables different curl sizes to be selected.
A rotating mechanism may for example be used to adjust the barrel size. It may be electrically adjusted using an internal motor or manually adjusted. The barrel size may for example be controlled to increase during setting of curls to provide additional tension.
The hair curler may instead comprise a set of (non-adjustable) heating barrels of different sizes, wherein different designs of roller arrangement are provided with the different heating barrels. Thus, different treatment liquids may be used for different curl sizes.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the invention, and to show more clearly how it may be carried into effect, reference will now be made, by way of example only, to the accompanying drawings, in which:

Fig. 1 shows an example of the type of hair curler to which the invention may be applied;
Fig. 2 shows a first example of treatment liquid application system;
Fig. 3 shows a second example of treatment liquid application system;
Fig. 4 shows a third example of treatment liquid application system;
Fig. 5 shows a fourth example of treatment liquid application system;
Fig. 6 shows a first example of a roller in more detail;
Fig. 7 shows a second example of a roller in more detail;
Fig. 8 shows a third example of a roller in more detail; and
Fig. 9 shows a fourth example of a roller in more detail.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The invention will be described with reference to the Figures.
It should be understood that the detailed description and specific examples, while indicating exemplary embodiments of the apparatus, systems and methods, are intended for purposes of illustration only and are not intended to limit the scope of the invention. These and other features, aspects, and advantages of the apparatus, systems and methods of the present invention will become better understood from the following description, appended claims, and accompanying drawings. It should be understood that the Figures are merely schematic and are not drawn to scale. It should also be understood that the same reference numerals are used throughout the Figures to indicate the same or similar parts.
The invention provides an applicator which comprises a roller arrangement having at least one roller, wherein the roller comprises a central reservoir and a porous outer layer for transferring treatment liquid from the central reservoir to hair, wherein the roller is freely rotatable in use. The applicator is for example part of a hair curler which has a tubular heating barrel with a tubular sleeve around the heating barrel. The applicator functions as a treatment liquid application system, and one or more rollers are located along a path of the hair during winding on the tubular heating barrel and/or during removal of the hair from the hair curler. Thus, a protection topical may be applied before curling, a topical may be applied after curling, or both. The hair curler can for example apply treatment liquids before and after curling, and in an automatic way during use of the hair curler.
Fig. 1 shows an example of the type of hair curler 10 to which the invention may be applied. The applicator of the invention may however more generally be applied to any design of hair treatment device. For example, it may be applied to clamping type devices which comprises a pair of jaws which are clamped over the section of hair to be treated. The invention may be applied to a hair curler or a hair straightener.
The hair curler 10 of the example shown comprises a main body 12 having a handle 14 and a hair curling head 16. The hair curling head comprises a central cylindrical heating barrel 18 around which a sleeve 20 extends. The sleeve 20 has a lateral opening 22 into which hair can be received. The lateral opening is in the form of a longitudinal entry slit which is open at a distal end (i.e., the end opposite the handle) of the tubular sleeve.
The received hair is wound around the heating barrel 18 by a looper 24, i.e., a rotatable element for example having a blade form. There may for example be two loopers spaced around the heating barrel by 180 degrees. The looper 24 is driven to rotate around the heating barrel and it winds hair around the heating barrel. The hair between the heating barrel 18 and the sleeve 20 (the "curling space") is heated while in a wound condition.
The heating barrel comprises an internal heater (not shown) for heating an outer surface of the barrel, which will be in contact with hair wound around the barrel.
The hair curler has a controller 30 to control the temperature of the heater, which can evenly disperse the heat, circulate the heating process, improve the protein structure of the hair to create bends, and meanwhile protect the hair during the curling process.
The invention relates to a system for applying liquids to the hair, for example during the curling process performed by the hair curler of Fig. 1.
Liquid topicals may be used for hair protection, to protect hair against the applied heat.
Heat protection products are well known, for example to protect against the heat of a hair dryer. Heat protection liquids for example make use of silicones for heat protection. Typically, they also include conditional agents such as proteins and amino acids that help to nourish and strengthen the hair. Hair oils or serums may also be applied to nourish and/or moisturize the hair. These may also be based on silicones, and include oils (e.g., argan oil, coconut oil, jojoba oil) and/or vitamins.
Liquids may also be used for assisting fixation (i.e., setting). Fixation liquids typically comprise polymers that form a film on the hair, with alcohol to assist drying. Conditioning agents and/or oils and/or serums may also be applied post-styling together with the fixation product.
The invention provides a hair curler which enables treatment liquids to be applied before curling and/or after curling (and also optionally during curling).
Fig. 2 shows a first example of the application system for applying a treatment liquid or liquids.
An arrangement of one or more rollers is used to deliver liquid to the hair. The roller or rollers each comprise a central reservoir with a porous outer layer for transferring treatment liquid from the central reservoir to the hair. The porous outer layer is in the form of a porous pad for retaining liquid, and it releases liquid when contact is made with the surface of the pad, for example when pressure is applied to the surface of the pad. The pad thus has a sponge-like form. A pad thickness and porosity may be selected to achieve the desired release of liquid, in response to the contact and pressure applied by the hair in use of the hair curler. A more open pore structure will give greater storage capacity and a greater application rate.
The roller or rollers are freely rotatable. This results in more effective utilization of the treatment liquid. The rotation reduces the friction with the hair and allows a greater surface area to make contact with the hair. The roller is for example a replaceable item, and is for example packaged in a sachet.
The release of liquid absorbed into the pad may be enhanced by heating, whereby the liquid becomes less viscous when heated. Alternatively, the liquid may be shielded from the heat of the heating barrel.
The delivery of liquid from the central reservoir to the pad surface is typically passive, but it is also possible to employ an internal pumping system for assisting the delivery of liquid from central reservoir to the pad and from the pad to the hair, for example using a mechanical spring-loaded system or actuated using the thermal energy delivered by heating barrel.
However, in all cases, it is contact of the hair with a pad that causes a release of liquid to the hair, in contrast to a spray system.
In one example, the roller arrangement has at least one roller configured to be located along a path of the hair during winding around the tubular heating barrel. In another example, the roller arrangement has at least one roller configured to be located along a path of the hair during removal of the hair from the hair curler. In some examples, the roller arrangement includes separate rollers which are along the paths of the hair during winding as well as during removal.
Fig. 2 shows an example with first rollers 40 for applying liquid during winding of hair around the heating barrel and a second roller 42 for applying liquid during hair removal.
The first rollers 40 are located around the slit 22 which defines the hair entry channel into the curling space. The entry slit has a U-shape (which is intended to include non-parallel sides i.e., a V shape), so that the shape has opposing arms and a connecting base. Fig. 2 shows a rollers 40 provided along each of the arms of the U-shape. Instead, there may be a roller along only one arm.
Hair makes contact with the first rollers 40 when being wound around the heating barrel, causing the pads to release liquid onto the hair.
The second roller 42 is located at the top of the tubular heating barrel 18. Hair is removed from the curler by sliding longitudinally off the heating barrel. Thus, when hair is removed from the curling space, it passes across the top of the heating barrel, where the second roller 42 is located.
The second roller is shown with an axis of rotation parallel with the longitudinal axis of the heating barrel. However, it may instead have a rotation axis perpendicular to that shown. For example, there may be a set of rollers around the top of the heating barrel each with an axis of rotation perpendicular to the longitudinal axis, so that they rotate under the influence of hair sliding off the top of the heating barrel.
The first rollers 40 contain an absorbed heat protection liquid, whereas the second roller 42 contains an after-care or fixation treatment liquid. A treatment liquid may also be applied during curling, by having an additional pad arrangement within the curling space occupied by the hair during curling.
Fig. 3 shows an alternative positioning for the first roller 40. In this example, there is a single roller 50 extending along the length of the tubular heating barrel 18, mounted on the outside of the heating barrel. During winding, the hair passes over the roller 50 driven by the looper 24. There may instead be multiple rollers at different angular positions around the heating barrel.
The roller 50 may then be shielded from the heat of the heating barrel, for example by having a heat shielding layer between the roller 50 and the heating barrel. Instead, the heat may intentionally be used to assist the release of the liquid from the roller 50.
Fig. 4 shows another alternative positioning for the first roller. In this example, there is a roller 60 located on the looper 24.
Fig. 5 shows a further alternative design for the first roller. In this example, the an array of rollers 70 is arranged around a cylindrical sleeve 72.
The rollers 70 are rotatably mounted to the sleeve so that they each rotated about their own respective length axis, and the sleeve is fitted over the heating barrel. The liquid can be replenished by fitting a new sleeve or by replacing the rollers. The treatment liquid may for example be released from the central reservoirs with the assistance of the heating provided by the heating barrel. The rollers preferably extend parallel to the longitudinal axis of the heating barrel as shown, and hence extend along the length of the heating barrel.
Instead of rollers mounted on a sleeve, a single roller may be formed around the heating barrel, so that the central reservoir comprises an annulus concentric with, and around, the heating barrel. When a sleeve is used (with multiple rollers or formed as one roller), heat needs to be transferred from the heating barrel through the sleeve to the hair, so the sleeve is designed to allow the required heat transfer.
Fig. 6 shows one example of a roller 40. The central reservoir 44 has a generally cylindrical form with a recess 46 at each end. The hair curler comprises pins 48 which define rotation axles housed within the recesses about which the roller rotates.
The outer surface of the central reservoir 44 has porous regions 45 (or is fully formed as a porous structure) to enable liquid to transfer from the reservoir 44 to the porous outer layer, which is in the form of an external pad 47. The porous regions 45 are for example defined by a perforated outer wall which interfaces with the external pad.
In preferred examples, the roller is replaceable (or the roller can be removed to refill the central reservoir). The pins 48, or at least of the pins, is for example spring loaded, so that it can be retracted to allow the roller to be installed and removed.
Fig. 7 shows another example of a roller 40. The central reservoir 44 again has a generally cylindrical form but with a recess 46 at one end and a pin 43 at the other end. The recess is for engaging with a centering boss of the hair curler, for centering the rotation of the roller. The pin 43 is for example spring-loaded, so it can be retracted to enable the roller to be installed and removed. Alternatively, the pin 43 is rigid and the hair curler has a spring-loaded receiving bore so that the roller is held in place by the spring force of the bore and can be removed by sliding the roller against the spring bias towards the pin. The recess 46 can then be removed from the centering boss of the hair curler.
The roller may be configurable to be in a sealed state or a liquid delivery state. For example a sealed state may be used during storage, before fitting the roller to the hair curler. Optionally, the roller may be configured to a sealed state when the hair curler is not in use. This prevents leakage of treatment liquid when the roller is not being used for applying treatment liquid to the hair.
Fig. 8 shows an example in which the roller comprises two hollow cylinders 80, 82 with the porous outer (pad) around the outside. The two hollow cylinders are arranged concentrically and in contact with each other. Each cylinder is perforated with an array of openings (as shown schematically for the outer cylinder). The two cylinders can be rotated relative to each other between a first configuration in which the holes of the perforations are aligned and a second configuration in which the holes of the perforations of one cylinder are aligned with the solid parts of the other cylinder. In this way, the first configuration is a treatment liquid delivery configuration allowing liquid to pass from the central reservoir to the external pad, and the second configuration is a sealed (leakage preventing) configuration.
In one example, the sealed configuration is used during storage, for example with the roller in a sachet. The user then performs a relative rotation of the cylinders before installing the roller.
In another example, the hair curler has a drive mechanism for implementing he relative rotation, so that the treatment liquid only reaches the pad when the hair curler is in use. For example, whenever the hair curler is powered, the roller may be set to the liquid delivery configuration, whereas when powered off the roller is returned to a sealed configuration.
Alternatively, there may be manual adjustment of the roller even when fitted to the hair curler, so that the user can manually choose whether to allow or prevent treatment liquid delivery.
The example of Fig. 8 requires two close-fitting cylinders to prevent leakage and also requires the two cylinders to be able to rotate relative to each other, This requires a precise design of the cylinders.
Fig. 9 shows an example in which the design conditions can be relaxed. A main cylinder 90 is perforated and hence provided with one or more openings. For simplicity, Fig. 9 shows two openings. This main cylinder defines the main central reservoir of the roller.
A closing member is provided for closing the openings. In the example shown, the closing member comprises projections 92 which engage with the openings. The projections 92 are for example silicone features. The projections then either block the openings or release the openings, to enable the internal volume to be opened or closed.
The projections may be individual units or they may be connected together, for example as a second cylinder.
In the example shown, the projections 92 are located inside the main cylinder 90 so that each projection passes through the main cylinder 90 and blocks a respective opening while applying a preload pressure for example delivered by a spring 94. The projections are aligned with the openings, and remain aligned with the openings.
The closing member is operated by an actuator 96. The actuator is for example a pusher outside the outer cylinder which pushes the projections back, against the preload of the springs, to open the passageways to the central reservoir.
In the example shown, the actuator is a perforated outer cylinder which can slide up/down or rotate so that when a perforation of the outer cylinder is aligned with a projection, the projection closes its opening, whereas when a solid part of the outer cylinder is aligned with a projection, it pushes the projection back to open the opening.
The actuator may instead move in a radial direction to push against the projections in the direction in which they retract.
The closing member may be inside the cylinder (as shown) or at the outside of the cylinder. The actuator for driving the closing member may also have different designs. There may be a manually operated switch connected to the closing member. When the user operates the switch, the closing member is moved to open or close the openings of the main cylinder.
In this way, the tolerances are relaxed since a seal is no longer required between concentric cylinders. Any suitable design of closing member may be used.
In the example above, the closing member is generally static whereas the actuator is moved to engage with the closing member or not engage with the closing member. Instead, the closing member may be movable as a whole (so avoiding the need for an additional actuator). For example, the closing member may comprise a cylinder with spring-loaded projections. The projections will press into the openings of the main cylinder when aligned with those openings, or will press against solid parts of the main cylinder when moved to a position in which they are not aligned with the openings of the main cylinder. Thus, the closing member is moved so that the projections either align or do not align with the openings.
Any suitable mechanical design may be used to enable the roller to rotate freely and also to be removable. Preferably, the roller has the simplest design so that the replaceable part has the lowest cost. For example, the spring-loaded retention features may all be part of the body of the hair curler.
The heating barrel may have an adjustable size. This enables different curl sizes to be selected. A rotating mechanism may for example be used to adjust the barrel size. It may be electrically adjusted using an internal motor or manually adjusted. The barrel size may for example be controlled to increase during setting of curls to provide additional tension.
The roller arrangement may be designed such that a single design can be used and it can remain in place during barrel size adjustment. This applies self-evidently to rollers on the outer sleeve (Fig. 2) or on the looper (Fig. 4). Rollers mounted to the heating barrel such as shown in Fig. 3 may also remain in place if they are positioned such that they do not overlap the size adjustment areas of the heating barrel. For the sleeve design of Fig. 5, different sleeve sizes will be needed for different barrel size settings.
The hair curler may instead comprise a set of (non-adjustable) heating barrels of different sizes. A same roller design may be designed to fit to different barrel sizes, or else different designs roller arrangement are provided with the different heating barrels. Different treatment liquids may also be used for different curl sizes. For a sleeve design, a different sleeve will be provided for the different barrel sizes.
Variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality.
The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.
If the term "adapted to" is used in the claims or description, it is noted the term "adapted to" is intended to be equivalent to the term "configured to". If the term "arrangement" is used in the claims or description, it is noted the term "arrangement" is intended to be equivalent to the term "system", and vice versa.
Any reference signs in the claims should not be construed as limiting the scope.

Claims

An applicator for applying a treatment liquid to the hair, comprising:
a roller arrangement comprising at least one roller, wherein the roller comprises a central reservoir (44) and a porous outer layer (47) for transferring treatment liquid from the central reservoir to the hair, wherein the roller is freely rotatable in use.
The applicator of claim 1, wherein the central reservoir has a perforated outer wall (45) which interfaces with the porous outer layer (47).
The applicator of claim 2, wherein the central reservoir has first and second perforated outer walls (80,82) arranged concentrically with respect to each other, and rotatable relative to each other between a sealed configuration and a liquid release configuration.
The applicator of claim 2, wherein the central reservoir has a perforated wall, wherein the applicator further comprises a closing member for opening and closing the perforations of the perforated outer wall, wherein the closing member is movable between open and closed states.
The applicator of claim 4, wherein the closing member comprises projections which extend though the perforations and the applicator further comprises a pusher for pushing against the projections.
A hair curler (10), comprising:
a tubular heating barrel (18) around which hair is to be wound for curling;

a tubular sleeve (20) around the heating barrel (18), wherein the sleeve has a longitudinal entry slit (22) for receiving hair to be wound on the tubular heating barrel (18); and

the applicator of any of claims 1 to 5, wherein the roller is configured to be located along a path of the hair during winding on the tubular heating barrel and/or along a path of the hair during removal of the hair from the hair curler.
The hair curler of claim 6, wherein the treatment liquid comprises at least one of a heat protection liquid, an after-care liquid, and a fixation liquid.
The hair curler of any one of claims 6 to 7, wherein the entry slit (22) has a U-shape or V-shape with two arms and a connecting base, and wherein the roller (40) is provided along at least one arm of the U-shape or V-shape.
The hair curler of claim 8, wherein the roller arrangement comprises rollers (40) provided along at least both arms of the U-shape or V-shape.
The hair curler of any one of claims 6 to 9, wherein the roller arrangement comprises a roller (50) provided on the outside of the tubular heating barrel.
The hair curler of any one of claims 6 to 10, further comprising a looper (24) for looping hair around the heating barrel, wherein the roller arrangement comprises a roller (60) provided on the looper (24).
The hair curler of any one of claims 6 to 11, wherein the roller arrangement comprises a roller (42) located at the top of the tubular heating barrel.
The hair curler of any one of claims 6 to 12, wherein the central reservoir comprises a cylindrical body with a recess (46) at each end, and the hair curler comprises axles (48) housed within the recesses.
The hair curler of any one of claims 6 to 13, wherein the central reservoir comprises a cylindrical body with a projecting pin (43) at one end extending along an axis of rotation and a centering recess (46) at the other end.
The hair curler of any one of claims 6 to 14, wherein:
the heating barrel has adjustable size; or

the hair curlier comprises a set of heating barrels of different sizes, wherein different designs of application pad arrangement are provided with the different heating barrels.