Heating element and heater assemblies, cartridges, and e-vapor devices including a heating element

Abstract

In an example embodiment, a heater assembly for an electronic heating device includes a heating element and a support. The heating element includes a planar portion, a first lead, and a second lead. The planar portion includes a filament. The filament defines an air channel through the planar portion. The filament includes a plurality of curves. At least one of the curves has a tip thereon. At least one of the first lead portion, the second lead portion, or both the first lead portion and the second lead portion are generally coplanar with the planar portion of the heating element. The heating element is in contact with the support such that the tip of the at least one of the curves rests thereon.

Description

BACKGROUND

Field

At least some example embodiments relate generally to an electronic vaping (e-vaping or e-vapor) device.

Related Art

Electronic vaping devices are used to vaporize a pre-vapor formulation into a vapor. These electronic vaping devices may be referred to as e-vaping devices. E-vaping devices include a heater, which vaporizes the pre-vapor formulation to produce the vapor. The e-vaping device may include several e-vaping elements including a power source, a cartridge or e-vaping tank including the heater and a reservoir capable of holding the pre-vapor formulation.

SUMMARY

At least one example embodiment relates to a heater assembly.

In at least one example embodiment, a heater assembly comprises a heating element including a planar portion including a filament, the filament defining an air channel through the planar portion, the filament arranged so as to form a plurality of curves, each of the curves having a closed end and an open end, and at least one of the curves having a tip thereon, a first lead portion, and a second lead portion. At least one of the first lead portion, the second lead portion, or both the first lead portion and the second lead portion are generally coplanar with the planar portion of the heating element. The heater assembly also includes a support. The heating element is in contact with the support such that the tip of the at least one of the curves rests thereon.

In at least one example embodiment, at least one of the curves generally has a keyhole shape. In at least one example embodiment, at least one of the curves generally has an omega shape. In at least one example embodiment, at least one of the curves generally has a U-shape. In at least one example embodiment, the tip extends from the closed end of the at least one of the curves. In at least one example embodiment, the filament defines the air channel through a central area of the planar portion. In at least one example embodiment, the tip of the at least one of the curves extends away from the air channel, and the open end of each of the curves is adjacent the air channel.

In at least one example embodiment, the filament includes stainless steel. In at least one example embodiment, the filament follows a circuitous path. A width of the filament varies along the circuitous path. In at least one example embodiment, a width of the filament gradually increases in a direction away from the air channel.

In at least one example embodiment, the first lead portion extends into the air channel and the second lead portion extends away from the air channel.

In at least one example embodiment, the first lead portion and the second lead portion extend away from the air channel. The support includes a support ring. In at least one example embodiment, the support ring is formed of one or more materials including polyetheretherketone. In at least one example embodiment, the support ring includes at least one electrical contact molded within the support ring. In at least one example embodiment, the tip has a generally trapezoidal shape. In at least one example embodiment, the tip has a generally rectangular shape. In at least one example embodiment, the tip has a generally triangular shape.

In at least one example embodiment, at least one of the first lead portion, the second lead portion, or both the first lead portion and the second lead portion having a generally spiral shape.

In at least one example embodiment, at least one of the first lead portion, the second lead portion, or both the first lead portion and the second lead portion having a generally L-shape.

At least one example embodiment relates to a cartridge for an e-vapor device.

In at least one example embodiment, a cartridge for an e-vapor device, comprises a housing, a reservoir in the housing, a transfer material adjacent a portion of the reservoir, and a heater assembly. The heater assembly includes a heating element and a support. The heating element includes a planar portion including a filament, the filament defining an air channel through the planar portion, the filament arranged so as to form a plurality of curves, each of the curves having a closed end and an open end, and at least one of the curves having a tip thereon, a first lead portion, and a second lead portion. At least one of the first lead portion, the second lead portion, or both the first lead portion and the second lead portion are generally coplanar with the planar portion of the heating element. The heating element is in contact with the support such that the tip of the at least one of the curves rests thereon.

In at least one example embodiment, the planar portion, the first lead portion, and the second lead portion are a unitary body.

In at least one example embodiment, the cartridge further comprise an inner tube within the housing. The inner tube defines an airway through the housing, and an outer surface of the inner tube and an inner surface of the housing at least partially define a portion of the reservoir.

In at least one example embodiment, the filament includes stainless steel. The filament follows a circuitous path. In at least one example embodiment, a width of the filament varies along the circuitous path. In at least one example embodiment, the width of the filament gradually increases in a direction away from the air channel. In at least one example embodiment, the first lead portion extends into the air channel and the second lead portion extends away from the air channel. In at least one example embodiment, the first lead portion and the second lead portion extend away from the air channel.

In at least one example embodiment, the support includes a support ring. The support ring is formed of one or more materials including polyetheretherketone. The support ring includes at least one electrical contact molded within the support ring.

In at least one example embodiment, the tip of the at least one of the curves has a generally trapezoidal shape. In at least one example embodiment, the tip of the at least one of the curves has a generally rectangular shape. In at least one example embodiment, the tip of the at least one of the curves has a generally triangular shape.

In at least one example embodiment, at least one of the first lead portion, the second lead portion, or both the first lead portion and the second lead portion having a generally spiral shape. In at least one example embodiment, at least one of the first lead portion, the second lead portion, or both the first lead portion and the second lead portion having a generally L-shape.

In at least one example embodiment, the support is a generally cylindrical wall having a top edge, and the tip of the at least one of the curves rests on the top edge of the generally cylindrical wall. In at least one example embodiment, at least one of the curves generally has a keyhole shape. In at least one example embodiment, at least one of the curves generally has an omega shape. In at least one example embodiment, at least one of the curves generally has a U-shape. In at least one example embodiment, the tip extends from the closed end of the at least one of the curves. In at least one example embodiment, the tip has a generally pointed shape.

In at least one example embodiment, the heating element is in contact with the transfer material.

In at least one example embodiment, the tip of the at least one of the curves has a generally pointed shape.

BRIEF DESCRIPTION OF THE DRAWINGS

The various features and advantages of the non-limiting embodiments herein may become more apparent upon review of the detailed description in conjunction with the accompanying drawings. The accompanying drawings are merely provided for illustrative purposes and should not be interpreted to limit the scope of the claims. The accompanying drawings are not to be considered as drawn to scale unless explicitly noted. For purposes of clarity, various dimensions of the drawings may have been exaggerated.

FIGS. 1A-1C are perspective views of a heating element and portions of the heating element according to at least one example embodiment.

FIGS. 2A and 2B illustrate a heating element according to at least one example embodiment.

FIGS. 3A and 3B are perspective views of heating elements according to at least one example embodiment.

FIGS. 4A and 4B are cross-sectional views of an e-vapor device including a heating element according to an example embodiment.

FIGS. 5A-5H illustrate elements of a cartridge of the e-vapor device in FIG. 4.

FIG. 6 is a three-dimensional rendering of the cartridge shown in FIGS. 5A and 5B.

FIG. 7 is a perspective view of a heater assembly according to at least one example embodiment.

FIG. 8 is a partial cross-sectional view of a cartridge including the heater assembly of FIG. 7 according to at least one example embodiment.

FIG. 9 is a perspective view of a heating element for use in the cartridge of FIG. 8 according to at least one example embodiment.

FIG. 10 is a top view of a heater assembly including a heating element according to at least one example embodiment.

FIG. 11 is an exploded view of the heater assembly of FIG. 10 according to at least one example embodiment.

FIG. 12 is an exploded view of a cartridge including the heating element of FIG. 10 according to at least one example embodiment.

FIG. 13 is a perspective view of a heater assembly according to at least one example embodiment.

FIG. 14 is a perspective view of a heater assembly according to at least one example embodiment.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

Some detailed example embodiments are disclosed herein. However, specific structural and functional details disclosed herein are merely representative for purposes of describing example embodiments. Example embodiments may, however, be embodied in many alternate forms and should not be construed as limited to only the embodiments set forth herein.

Accordingly, while example embodiments are capable of various modifications and alternative forms, embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that there is no intent to limit example embodiments to the particular forms disclosed, but to the contrary, example embodiments are to cover all modifications, equivalents, and alternatives falling within the scope of example embodiments. Like numbers refer to like elements throughout the description of the figures.

It should be understood that when an element or layer is referred to as being “on,” “connected to,” “coupled to,” or “covering” another element or layer, it may be directly on, connected to, coupled to, or covering the other element or layer or intervening elements or layers may be present. In contrast, when an element is referred to as being “directly on,” “directly connected to,” or “directly coupled to” another element or layer, there are no intervening elements or layers present. Like numbers refer to like elements throughout the specification. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.

It should be understood that, although the terms first, second, third, etc. may be used herein to describe various elements, regions, layers and/or sections, these elements, regions, layers, and/or sections should not be limited by these terms. These terms are only used to distinguish one element, region, layer, or section from another region, layer, or section. Thus, a first element, region, layer, or section discussed below could be termed a second element, region, layer, or section without departing from the teachings of example embodiments.

Spatially relative terms (e.g., “beneath,” “below,” “lower,” “above,” “upper,” and the like) may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It should be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the term “below” may encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

The terminology used herein is for the purpose of describing various embodiments only and is not intended to be limiting of example embodiments. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “includes,” “including,” “comprises,” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, and/or elements, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, and/or groups thereof.

Example embodiments are described herein with reference to cross-sectional illustrations that are schematic illustrations of idealized embodiments (and intermediate structures) of example embodiments. As such, variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and/or tolerances, are to be expected. Thus, example embodiments should not be construed as limited to the shapes of regions illustrated herein but are to include deviations in shapes that result, for example, from manufacturing. Thus, the figures are schematic in nature and their shapes are not intended to illustrate the actual shape of a region of a device and are not intended to limit the scope of example embodiments.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which example embodiments belong. It will be further understood that terms, including those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

FIGS. 1A-1C are perspective views of a heating element and portions of the heating element according to at least one example embodiment.

FIG. 1A illustrates a heating element 10 for an e-vapor device. The heating element 10 includes a planar portion 20 having at least one filament 50. The filament 50 may define an air channel 60 through the planar portion 20. For example, the filament 50 defines the air channel 60 through a central area of the planar portion 20 (e.g., such that air flowing through the central area is unobstructed). The air channel 60 may have a substantially circular shape.

The planar portion 20 (with the filament 50) may have a substantially flat or planar structure. Alternatively, a portion of the filament 50 may be punched in or punched out so as to change the flat structure into a three-dimensional structure. This may allow for the heating element 10 to heat additional surface area of a porous substrate of an e-vapor device. The structure of the filament 50 is described in further detail below with reference to FIGS. 1B and 1C.

The heating element 10 may include stainless steel or alloy thereof. Stainless steel (e.g., stainless steel 304) has a relatively high temperature coefficient, which allows for accurate temperature control of the filament 50. Alternatively, the heating element 10 may include Nichrome (e.g., 80% nickel, 20% chromium) or other materials. Examples of other suitable electrically resistive materials for the heating element 10 include titanium, zirconium, tantalum, and metals from the platinum group. Examples of suitable metal alloys include stainless steel, nickel-, cobalt-, chromium-, aluminum-, titanium-, zirconium-, hafnium-, niobium-, molybdenum-, tantalum-, tungsten-, tin-, gallium-, manganese-, and iron-containing alloys, and super-alloys based on nickel, iron, cobalt, and stainless steel. For instance, the heating element 10 may include nickel aluminides, a material with a layer of alumina on the surface, iron aluminides, and other composite materials. The electrically resistive material may optionally be embedded in, encapsulated, or coated with an insulating material or vice-versa, depending on the kinetics of energy transfer and the external physicochemical properties required. In a non-limiting example embodiment, the heating element 10 may comprise at least one material selected from the group consisting of stainless steel, copper, copper alloys, nickel-chromium alloys, superalloys, and combinations thereof. In another non-limiting example embodiment, the heating element 10 includes iron-chromium alloys. A higher resistivity for the heating element 10 lowers the current draw or load on the power supply or battery of an e-vapor device.

Still referring to FIG. 1A, the heating element 10 may include a first lead portion 30 and a second lead portion 40 extending away from the planar portion 20. For example, the first lead portion 30 and the second lead portion 40 extend away from the planar portion 20 in a direction that is substantially perpendicular to the planar portion 20. As shown in FIG. 1A, the planar portion 20, the first lead portion 30, and the second lead portion 40 are a unitary body, which allows for efficient manufacturing of the heating element 10. For example, the heating element 10 may be initially formed as a substantially flat element before first and second lead portions 30 and 40 are bent as shown in FIG. 1A. Accordingly, the heating element 10 may be referred to as a single piece heating element. A tip 31 of the first lead portion 30 and a tip 41 of the second lead portion 40 may be bent or bendable in a direction that is parallel to the planar portion 20 (this bending is explicitly shown in FIGS. 2B and 5B, for example).

A height H10 of the heating element 10 may be between 6.0 mm and 10 mm, for example, 8.5 mm. A width W10 of the heating element 10 may be between 4.5 mm and 5 mm, for example, 4.72 mm. A width W20 of the first lead portion 30 and the second lead portion 40 may be between 1.0 mm and 3.0 mm, for example, 1.9 mm. A length L10 of the heating element 10 may be between 4.7 mm and 7.8 mm, for example, 7.4 mm. A thickness T10 of the planar portion 20 may be between 0.05 mm and 0.30 mm, for example, 0.10 mm. The thickness T10 may be uniform throughout the planar portion 20, the first lead portion 30, and the second lead portion 40. However, example embodiments are not limited thereto. For example, the thickness of the planar portion 20 may be less than a thickness of the first lead portion 30 and the second lead portion 40.

The first lead portion 30 and the second lead portion 40 may be substantially rectangular shaped and have step portions 33 and 35 at ends closest to the planar portion 20. Step portions 35 may rest on a surface of a support for the heating element 10 while step portions 33 may provide a force that allows for the heating element 10 to be push fit into the support (see support 350 in FIGS. 5A and 5B, for example). Although two step portions 33 and 35 are shown, the first and second lead portions 30 and 40 may have one step portion or additional step portions as desired.

As illustrated in further detail by FIG. 1B, the filament 50 may follow a circuitous or sinuous path 51 to define the air channel 60. For example, the filament 50 may follow the circuitous path 51 such that the air channel 60 is substantially circular and has a diameter d10 between 1.2 mm and 2.0 mm, for example, 1.6 mm. The filament 50 may have a diameter d20 between 3.0 mm and 7.0 mm, for example, 4.1 mm. The filament 50 may be spaced apart from other sections of the planar portion 20 except at connection points 25 and 26. As a result, the electrical connection between the first lead portion 30 and the second lead portion 40 is through the filament 50 (i.e., during operation, current must travel between lead portions 30 and 40 through filament 50 and parts of the planar portion 20 connected to the connection points 25 and 26).

As illustrated in further detail by FIG. 1C, the filament 50 includes a plurality of filament portions 70 that are substantially u-shaped. The plurality filament portions 70 change from one to the other at end sections 80 of each u-shape. As further illustrated by FIG. 1C, a width of the filament 50 may vary along the circuitous path 51. For example, as indicated by increasing widths W30, W40, and W50, the width of the filament 50 gradually increases in a direction away from the air channel 60. A width W30 may be between 0.05 mm and 0.30 mm, for example. A width W40 may be between 0.05 mm and 1.0 mm, for example 0.16 mm. A width W50 may be between 0.25 mm and 1.00 mm, for example, 0.65 mm. A length L20 of each filament portion 70 may be between 0.5 mm and 3.5 mm, for example, 2.5 mm. It should be understood that a number of filament portions 70 may vary as desired. For example, the number of filament portions 70 may be between 3 and 25.

Spaces 110 between adjacent ones of the plurality of filament portions 70 may gradually increase in a direction away from the air channel 60. For example, a width W60 of the space 110 closest to the air channel 60 may less than a width W70 of the space 110 furthest from the air channel 60. In at least one example embodiment, a width W60 and a width W70 may be set so that a widest section of the spaces 110 at width W70 occupies between 2° and 90°, for example, 8.3° of a 360° circle around the filament 50 (shown in FIG. 1C by angle θ). The same dimensions may be set for widths W75 and W80 of spaces 111 between u-shaped portions of each filament portion 70. However, example embodiments are not limited thereto, and the spaces 110 and the spaces 111 may have different dimensions as desired. A length L30 between an end of space 111 that is furthest from the air channel 60 and a part of the u-shaped portion furthest away from the air channel 60 may be between 0.1 mm and 0.7 mm, for example, 0.3 mm.

A thickness T20 of the filament portions 70 may be between 0.05 mm and 0.30 mm, for example, 0.10 mm.

Due to the above described structure, the filament 50 may generate a gradient of heat that is most intense near the air channel 60 and gradually dissipates in a direction away from the air channel 60. It should be understood that an electrochemical etching process may be used to manufacture heating element 10 with the above described dimensions. Alternatively, the heating element 10 may be formed using a stamping process. It should also be understood that some parts of or the entire heating element 10 may be scaled up or down (e.g., scaled up 2.5 times larger than described above) depending on the desired implementation an e-vapor device.

FIGS. 2A and 2B illustrate a heating element according to at least one example embodiment. For example, FIG. 2A is a top-view of a heating element 10′ before bending and FIG. 2B is a perspective view of the heating element 10′ after bending.

As illustrated in FIGS. 2A and 2B, heating element 10′ is similar to the heating element 10 in FIGS. 1A-1C, and includes a planar portion 20′, a first lead portion 30′, a second lead portion 40′. However, heating element 10′ does not include an air channel 60 through the filament 50′. The transition from FIG. 2A to FIG. 2B shows how the heating element 10′ in FIG. 2A is bent along the dotted lines to form the heating element 10′ in FIG. 2B with bent first and second lead portions 30′ and 40′ and bent tips 31′ and 41′. It should be appreciated that tips 31 and 41 in FIG. 1 may be bent in the same manner as shown by tips 31′ and 41′ in FIG. 2B.

FIGS. 3A and 3B are perspective views of heating elements according to at least one example embodiment.

FIG. 3A is a perspective view of a dual heating element according to at least one example embodiment. The dual heating element 10″ may include two or more heating elements (e.g., two heating elements 10 from FIG. 1) stacked on top of one another. The heating elements 10 may be electrically connected to one another via welding, soldering, or a pressure-based connection. If a porous substrate in fluid communication with a pre-vapor formulation is placed between the two heating elements 10, the dual heating element 10″ may uniformly heat both sides of the porous substrate to create a high efficiency vapor production. A pre-vapor formulation is a material or combination of materials that may be transformed into a vapor. For example, the pre-vapor formulation may be a liquid, solid, and/or gel formulation including, but not limited to, water, beads, solvents, active ingredients, ethanol, plant extracts, natural or artificial flavors, and/or vapor formers such as glycerine and propylene glycol.

Although FIG. 3A shows that the dual heating element 10″ may be formed from two heating or more elements 10, it should be understood that the dual heating element 10″ may include two or more heating elements 10′ from FIGS. 2A and 2B, or one or more heating elements 10 and one or more heating elements 10′ stacked in a desired configuration.

FIG. 3B is a perspective view of a heating element according to at least one example embodiment. FIG. 3B illustrates a heating element 10′″ with a filament 50′″ that defines an opening 60′″. The heating element 10′″ may have substantially the same dimensions as the heating element 10 from FIGS. 1A-1C except that the filament 50′″ has filament portions 70′″ that have a substantially same width and substantially rounded ends throughout the circuitous or sinuous path.

FIGS. 4A and 4B are cross-sectional views of an e-vapor device including a heating element according to an example embodiment.

FIGS. 4A and 4B illustrate sections of an e-vapor device 200. For example, the e-vapor device 200 may have a mouthpiece section 210, a cartridge 220, and a power supply section 230. The mouthpiece section 210 may fit (e.g., pressure fit, or thread fit) onto the cartridge 220 in order to allow for an adult vaper to apply a negative pressure to the mouthpiece section 210 and draw vapor from e-vapor device. It should be understood that the mouthpiece 210 may be excluded from the configuration shown in FIGS. 4A and 4B or integrated with the cartridge 220 to reduce the number of parts. The cartridge 220 may include a heating element (e.g., one of the heating elements of FIGS. 1A-3). The cartridge 220 may be replaceable. The cartridge 220 is described in more detail below with reference to FIGS. 5A-5H, and 6. The cartridge 220 and the power supply section 230 may be releasably connected (e.g., by a threading engagement). Alternatively, the cartridge 220 and the power supply section 230 may be in a unitary housing.

The power supply section 230 may be configured to selectively supply power to the heating element in the cartridge 220 via a battery 250. The power supply section 230 may include an indicator 235, control electronics 240, battery 250, air inlet 255, conductive post 260, and a connector 265. The indicator 235 may be, for example, a light emitting diode (LED) located at one end of the power supply section 230. The LED may flash different colors and/or different patterns to indicate different information about the e-vapor device 200. For example, the LED may flash one color to indicate activation of the e-vapor device 200 and another color to indicate a battery level of the battery 250. However, example embodiments are not limited thereto, and the LED may be used to indicate other information through various colors and patterns of flashes.

The battery 250 may selectively supply power to the indicator 235, the control electronics 240, and the heating element 10 (see FIGS. 5A and 5B). For example, the battery 250 may selectively supply power under a control of the control electronics 240. The control electronics 240 may include control circuitry including a puff sensor for sensing a negative pressure applied by an adult vaper. The puff sensor is operable to sense an air pressure drop in the e-vapor device 200, which causes the control electronics 240 to initiate the application of voltage from the battery 250 to the heating element 10. For example, if the puff sensor indicates that an adult vaper is applying a negative pressure to the e-vapor device 200, the control electronics 240 initiates a puff cycle by connecting the battery 250 to the heating element 10 to heat the heating element 10, thereby vaporizing a pre-vapor formulation in a porous substrate in contact with the heating element 10. Upon termination applying negative pressure by an adult vaper, the puff sensor ceases to sense the air pressure drop and the control electronics 240 disconnects the battery 250 from the heating element 10 to end the puff cycle.

The control electronics 240 may be between the indicator 235 and the battery 250 within the power supply section 230. The connector 265 may facilitate a threaded connection to the cartridge 220. For example, the threaded connection may be a combination of a conductive male threaded member on the connector 265 and a conductive or non-conductive female threaded receiver on the cartridge 220 (or vice versa). Alternatively, the threaded connection may be in a form of other suitable structures, such as a snug-fit, detent, clamp, and/or clasp arrangement. Although not explicitly shown, one terminal of the battery 250 is electrically connected to the conductive post 260 and the other terminal of the battery 250 is electrically connected to the connector 265 via the control electronics 240.

The power supply section 230 may include an air inlet/outlet 255 at an end of the power supply section 230 nearest to the control electronics 240. As shown by the arrows in in FIG. 4B, when air is drawn through the mouthpiece 210, air enters the tip of the e-vapor device 200 at air inlet/outlet 255, travels past the control electronics 240 that includes the puff sensor through the spaces provided around the puff sensor (thereby detecting a negative pressure and activating the heating element 10), and continues past the battery 250. The air then goes through an opening in the axis of a conductive post 260 of the battery's 250 male connector, and straight into a conductive rivet engaged with the female connector of the cartridge 220 (see element 360 in FIGS. 5A and 5B). The air is then inundated with particles of vapor (produced by the heating of a porous substrate containing a pre-vapor formulation as a result of the activated heating element 10) and exits through the mouthpiece section 210. As shown by the return arrows in FIG. 4B, excess vapor travels through the e-vapor device 200 and may be exhausted from the air inlet/outlet 255.

Although FIGS. 4A and 4B shows one air inlet/outlet 255, the e-vapor device 200 may include additional air inlets/outlets at other locations on the e-vapor device, for example, at or closer to a connection between the cartridge 220 and the power supply section 230. This may allow for air intake at other locations of the e-vapor device 200.

The battery 250 may be a Lithium-ion battery or one of its variants (e.g., a Lithium-ion polymer battery). The battery 250 may also be a Nickel-metal hydride battery, a Nickel cadmium battery, a Lithium-manganese battery, a Lithium-cobalt battery, or a fuel cell.

FIGS. 5A-5H illustrate elements of a cartridge of the e-vapor device in FIG. 4.

For example, FIG. 5A is an exploded view of a cartridge of the e-vapor device shown in FIG. 4. FIG. 5B is a cross-sectional view of the cartridge in FIG. 5A taken along line VB-VB′. FIGS. 5C-5H illustrate the details of various parts of the cartridge shown in FIGS. 5A and 5B.

FIGS. 5A and 5B illustrate that the cartridge 220 includes a housing 300. The housing 300 may include a reservoir portion 310 and a connector portion 320. The connector portion 320 is configured to connect the cartridge 220 to a power supply section (e.g., the power supply section 230 in FIG. 4). With reference to FIGS. 5A, 5B, and 5C, the connector portion 320 may be substantially hollow and have a substantially cylindrical shape. The connector portion 320 may include a female thread 321 for releasably engaging with a male thread of the connector 265 of power supply section 230 in FIG. 4. The connector portion 320 may be made of, for example, a synthetic polymer or other material suitable for e-vapor devices such as solid plastic, and/or metal (e.g., stainless steel). An inner wall of the connector portion 320 may be conductive or non-conductive. The connector portion 320 may include substantially rectangular tabs (e.g., flexible tabs) 510 and 520 on opposing edges of the connector portion 320. The tabs 510 and 520 provide a releasable snap fit connection to connection points 490 of the reservoir portion 310 (see FIG. 6). A body 525 of the connector portion 320 may have a height H20 of between 3.0 mm and 10.0 mm, for example, 4.70 mm. A diameter D30 of the connector portion 320 may be between 8.5 mm and 9.5 mm, for example, 9.0 mm. The diameter D30 may be larger or smaller depending on the application. For example, diameter D30 may be the same as the diameter D35 of the reservoir portion 310. Alternatively, the connector portion 320 and the power supply section 230 may be fixed together (i.e., not releasable).

With reference to FIGS. 5A, 5B, and 5D, the reservoir portion 310 is a storage portion configured to store a pre-vapor formulation in a cavity 311 of the reservoir portion 310. Although not shown, the cavity 311 may include a pre-vapor formulation containing material (e.g., a material to draw the pre-vapor formulation via capillary action). The reservoir portion 310 may have a substantially cylindrical shape and be made of, for example, a synthetic polymer or other material suitable for e-vapor devices such as, glass, ceramic, and/or metal (e.g., stainless steel). The reservoir portion 310 may have a closed end, an open end, and a cylindrically shaped inner tube 315 may define an airway 600 that passes through a central area of the reservoir portion 310 from the closed end to the open end. The airway 600 may have a diameter of between 1.0 mm and 4.0 mm, for example, 1.60 mm. The reservoir portion 310 may have a height H30 of between 15 mm and 60 mm, for example, 32.9 mm. The reservoir portion 310 may have a diameter D35 of between 6.5 mm and 25 mm, for example, 9.0 mm. That is, the reservoir portion 310 and the connector portion 320 may have a same diameter. The reservoir portion 310 includes at least two connection points 490 (due to the symmetry of reservoir portion 310, only one connection point 490 is shown in FIGS. 5A and 5D). Tabs 510 and 520 of the connector portion 320 may be releasably engaged with the at least two connection points 490 (see FIG. 6).

With reference to FIGS. 5A, 5B, and 5E, the reservoir portion 310 includes a porous substrate 400 in fluid communication with the cavity 311. The porous substrate 400 may be substantially disc shaped and have a diameter of between 5.0 mm and 24 mm, for example, 8.0 mm. The porous substrate may have a thickness T30 between 0.5 mm and 2.0 mm, for example, 1.0 mm. The porous substrate 400 may have a capacity to draw a pre-vapor formulation via capillary action as a result of the interstitial spacing between filaments of the porous substrate 400. For example, the porous substrate 400 may be a ceramic material or other porous material capable of withstanding varying temperatures of the heating element 10 such as a ceramic, mineral fibrous material, metal (in a honeycomb or mesh structure), and glass fibers. A central area of the porous substrate 400 includes an opening 410 with a diameter D40 between 1.0 mm and 4.0 mm, for example, 2.0 mm. The opening 410 may be aligned with the air channel 60 of the heating element 10 and with the airway 600 of the reservoir portion 310.

With reference to FIGS. 5A, 5B, and 5F, the reservoir portion 310 includes a gasket 420 configured to provide the fluid communication between the porous substrate 400 and the cavity 311. The gasket 420 may include rubber or silicon, or some other material capable of preventing pre-vapor formulation in the cavity 311 from passing between the gasket 420 and walls of the reservoir portion 310 such as organic elastomers and/or inorganic elastomers. The gasket 420 may have a thickness T40 between 1.0 mm and 3.0 mm, for example, 2.0 mm. The gasket 420 may have a diameter D50 between 7.7 mm and 8.5 mm, for example, 8.1 mm. It should be understood that the diameter D50 may vary from these values so long as the gasket 420 provides an effective seal in the reservoir 310. A central area of the gasket 420 includes an opening 440 with a diameter D53 between 2.6 mm and 2.8 mm, for example, 2.7 mm so that the gasket 420 fits around the airway 600. The gasket 420 is configured to provide the fluid communication between the porous substrate 400 and the cavity 311 via at least one aperture 430 disposed adjacent to the opening 440. According to at least one example embodiment, the gasket 420 includes two or more apertures 430 (e.g., four apertures) disposed in a diamond configuration on opposing sides of the opening 440. The apertures 430 may be substantially circular in shape and have a diameter D55 between 0.8 mm and 1.2 mm, for example, 1.0 mm. However, example embodiments are not limited to the shape and size of the apertures shown in FIG. 5F and it should be understood that the apertures 430 may be of various sizes and shapes so long as the porous substrate 400 does not become oversaturated with pre-vapor formulation and leak from the e-vapor device 200.

FIGS. 5A and 5B further illustrate that the cartridge 220 includes a heater assembly 330. The heater assembly 330 includes a heating element 10, a support 350, and a conductive rivet 360. The conductive rivet 360 may be optional. The heating element 10 may be, for example, one of the heating elements shown in FIGS. 1A-3.

With reference to FIGS. 5A, 5B, and 5G, the support 350 may support the heating element 10 and be disposed in the housing 300. The support 350 may include silicon or some other material capable of withstanding varying temperatures of the heating element 10 such as organic elastomers and/or inorganic elastomers. The support 350 may have a substantially cylindrical shape and a diameter D60 between 7.7 mm and 8.5 mm, for example, 8.1 mm. It should be understood that the diameter D60 may vary from these values so long as the support 350 provides an effective seal in the reservoir 310. A central area of an end surface of the support 350 includes a through hole 450 with a diameter D65 between 1.7 mm and 2.1 mm, for example, 1.93 mm. It should be understood that the diameter D65 may vary from these values so long as the support 35 provides an effective seal between an outer wall of the inner tube 315 and the gasket 420. The support 350 may have a height H40 between 3.0 mm and 8.0 mm, for example, 5.1 mm. The through hole 450 may be aligned with the air channel 60, opening 410, and airway 600. If the conductive rivet 360 is not used, then the support 350 may include grooves along a lateral surface of the support 350 instead of the through hole 450. Here, the grooves allow for the airflow formerly provided by the through hole 450 and electrical connection to the powers supply 250 is provided via direct connection with the tip 41.

A first slot 460 and a second slot 470 may be on the end surface of the support 35 and disposed at opposing sides of the through hole 450. The first slot 460 and the second slot 470 may have a shape and size that accommodates the first lead portion 30 and the second lead portion 40 of the heating element 10. For example, as shown in FIG. 5B, the slots 460 and 470 have substantially rectangular shapes so that the first lead portion 30 extends through first slot 460, and the second lead portion 40 extends through the second slot 470. As also shown in FIG. 5B, the first lead portion 30 and the second lead portion 40 are bent in a direction that is substantially parallel to the planar portion 20 at tips 31 and 41. Although tip 31 is shown in FIG. 5B as not contacting a wall of the connector portion 320, the tip 31 may extend to contact the wall of the connector portion 320 if desired. For example, if the inner wall of connector portion 320 is electrically conductive, the tip 31 may be extended to electrically connect to the inner wall of the connector portion 320 so that the first lead portion 30 is electrically connected to the connector portion 320. As shown in FIG. 5B, the support 350 may include a thin membrane 351 in the first and second slots 460 and 470. The membrane 351 may be penetrated by the first and second lead portions 30 and 40 upon assembly and provide a seal at the penetration point. A thickness of the membrane 351 may be between 0.1 mm and 1.0 mm, for example, 0.3 mm.

Still referring to FIGS. 5A, 5B, and 5G, the lateral surface of the support 350 may have a male thread engagement portion 530 for thread engagement with a female thread engagement of the reservoir portion 310. Alternatively, the support 350 may push fit into the reservoir portion 310. As another alternative, the support 350 may affixed to the reservoir portion 310 with ultrasonic welding. In yet another alternative, the support 350 and the reservoir portion 310 may have a bayonet connection. It should be appreciated that other connections between the support 350 and the reservoir portion 310 are within the scope of example embodiments. The support 350 may include at least two recesses 480 on opposing sides of the lateral surface of the support 350. The recesses 480 may have a size, shape, and location that accommodate the tabs 510 and 520 of the connector portion 320. As shown in FIG. 5G, the recesses 480 have a substantially rectangular shape and extend from one end of the support 350 to a stop surface 485 to provide a tight fit with the tabs 510 and 520 (see FIG. 6 for connection between connector portion 320 and reservoir portion 310).

With reference to FIGS. 5A, 5B, and 5H, the support 350 includes a conductive rivet 360 extending through the through hole 450. The conductive rivet 360 may include metal or some other conductive material such as a brass coat with a nickel base and sliver plating. The conductive rivet 360 may include a substantially cylindrical body portion 361 and a substantially circular head portion 363 at one end of the body portion 363. The body portion 361 may have a diameter D70 between 1.77 mm and 2.17 mm, for example, 2.0 mm such that the conductive rivet 360 may push fit into the through hole 450 of the support 350. Alternatively, the conductive rivet 360 may be welded or soldered to a tip 41 of the second lead portion 40. The head portion 363 may have a diameter D75 larger than diameter D70. Diameter D75 may be between 2.5 mm and 4.5 mm, for example, 4.0 mm. The conductive rivet 360 may be substantially hollow. For example, an airway 365 may pass through a central area of conductive rivet 360. The airway 365 may have a diameter D77 between 1.2 mm and 1.7 mm, for example, 1.6 mm. A height H50 from a top surface of the head portion 363 to an opposing end of the conductive rivet 360 may be between 4.0 mm and 7.1 mm, for example, 6.5 mm. A height H55 from an end of the conductive rivet 360 to a bottom surface of the head portion 363 may be between 3.6 mm and 6.7 mm, for example, 6.1 mm.

An electrical connection of the heating element 10 to the battery 250 is described below with reference to FIGS. 4A, 4B, 5A, 5B, and 5H. As shown in FIG. 5B, the bottom surface of the head portion 363 is in electrical contact with a tip 41 of the second lead portion 40 while the top surface of the head portion 363 is in electrical contact with the conductive post 260 of the power supply section 230. However, the head portion 363 is spaced apart from a tip 31 of the first lead portion 30 so as to be electrically isolated from the tip 31. The tip 31 of the first lead portion 30 is electrically connected to connector 265 of the power supply section 230 upon engagement of the cartridge 220 and power supply section 230. For example, the connector 265 may be a conductive male thread of the power supply section 230 that makes electrical contact with the tip 31 upon engagement with a female thread of the connector portion 320. Alternatively, if an inner wall of connector portion 320 (e.g., the female thread) is electrically conductive, the tip 31 may be extended to electrically connect to the inner wall of the connector portion 320 so that the first lead portion 30 is electrically connected to the connector portion 320. In this case, the conductive male thread of the connector 265 may be in electrical contact with tip 31 through the inner wall of the connector portion 320.

As explained with reference to FIGS. 4A and 4B, when an adult vaper draws air through the mouthpiece 210, the puff sensor in control electronics 240 is operable to sense an air pressure drop in the e-vapor device 200 to cause the control electronics 240 to initiate the application of voltage from the battery 250 to the heating element 10 via the above described electrical contacts between the conductive post 260, the conductive rivet 360, and the tip 41 and between the tip 31 and the connector 265. It should be understood that the puff sensor acts as a switch that completes a closed loop circuit through the heating element 10 upon sensing the air pressure drop. The heating element 10 heats vapor drawn into the filament 50 from the porous substrate 400 to form vapor, which enters the adult vaper's mouth via air channel 60, opening 410 and airway 600.

Although not explicitly shown in FIGS. 5A-5H, it should be understood that the support 350 may have alternative structures that allow air to pass through. For example, in addition to or an alternative to the location of the airway 365, there may be other airways at the outer edge of the support 350 so that air is able to pass between the reservoir portion 310 and the support 350. It should be further understood that the conductive rivet 360 may be eliminated. In this case, the connector 265 may be in electrical contact with the tip 41 without the conductive rivet 360 in between.

FIG. 6 is a three-dimensional rendering of the cartridge shown in FIGS. 5A-5H.

FIG. 6 shows a completed cartridge 220 that is ready for connection to the mouthpiece 210 and/or connection to power supply section 230 in FIG. 4 via the female thread 321. As illustrated in FIG. 6, the heating element 10 may be spaced apart from the end surface of the support 350 with the aid of step portions 33 and/or 35 to provide efficient heat transfer to the porous substrate 400.

FIG. 7 is a perspective view of a heater assembly according to at least one example embodiment.

In at least one example embodiment, as shown in FIG. 7, the heating element 710 may generally include one or more features of the heating element of FIG. 1A, and the first lead 730 and the second lead 740 are adjacent to one another, the filament 750 may include tip portions 700 that rest on a support 760, and the support 760 includes a support ring. Further, the heater 710 may be formed of a thicker metal material, such as a stainless steel foil, instead of including the leads 730, 740 that extend away from the planar portion 720 of the heating element 710, which provide support to the heating element 710 (some example embodiments may include both a thicker metal material as well as leads 730, 740 that extend away from the planar portion 720 of the heating element 710). In at least one example embodiment, the support 760 may be formed of a substantially heat-resistant material, such as polyetheretherketone (PEEK), ceramic, and/or a ceramic-coated metal.

In at least one example embodiment, the filament 750 is arranged such that a plurality of curves are formed. Each of the at least one curves generally has a keyhole shape, an omega shape, a U-shape, or any combination of these. In other example embodiments, the at least one curve has a rectangular, square, and/or polygonal shape. In at least one example embodiment, the filament 750 defines an air channel 60 through a central area of the planar portion 720 of the heating element 710. The tip portions 700 extend away from the air channel 60, and the open end of each of the curves is adjacent the air channel 60.

FIG. 8 is a partial cross-sectional view of a cartridge including the heater assembly of FIG. 7 according to at least one example embodiment.

In at least one example embodiment, as shown in FIG. 8, a first contact 770 and a second contact 780 are overmolded in the support 760, such that the first contact 770 is electrically isolated from the second contact 780. The leads 730, 740 of the heating element 710 may each be spot-welded or otherwise placed into contact with a respective one of the first contact 770 and the second contact 780.

In at least one example embodiment, as shown in FIG. 8, the heating element 710 may contact at least one transfer material 725, such as the transfer material disclosed in application Ser. No. 15/729,895 filed Oct. 11, 2017, the entire content of which is incorporated herein by reference, and/or any other suitable transfer material. In some example embodiments, the heating element 710 may be spaced apart from the transfer material 725, and a wick (not shown) may be placed between the transfer material 725 and the heating element 710.

FIG. 9 is a perspective view of a heating element for use in the cartridge of FIG. 8 according to at least one example embodiment.

In at least one example embodiment, as shown in FIG. 9, the heating element 910 is generally the same as in FIGS. 7-8, except that one or more of the tip portions 900 that extend from the filament 950 are generally trapezoidal or rectangular in shape. The first lead 930 and the second lead 940 are generally L-shaped.

FIG. 10 is a top view of a heater assembly including a heating element according to at least one example embodiment.

In at least one example embodiment, as shown in FIG. 10, one or more features of the heating element 1010 are generally the same as in FIGS. 7-8, and the first lead 1030 extends into the air channel 1060 and the second lead 1040 extends outwardly.

FIG. 11 is an exploded view of the heater assembly of FIG. 10 according to at least one example embodiment.

In at least one example embodiment, a support 1105 is a ring 1100 that may be formed of one or more of PEEK, ceramic, and/or a ceramic coated metal. The ring 1100 is sized and configured to mate with a base portion 1110 that is formed of an electrically conductive material. The base portion 1110 is generally cylindrical and includes at least one air channel 1115 defined in an outer surface 1120 of the base portion 1110. The base portion 1110 also defines a passage 1130 extending through the base portion 1110 from a first end to a second end thereof. The base portion 1110 also includes a protrusion 1125 extending longitudinally from a top surface 1135 of the base portion 1110. The second lead 1040 of the heating element 1010 contacts the protrusion 1125 to form a first electrical contact. An electrically insulating shell 1150 in the form of a ring is positioned at a second end 1155 of the base portion 1110. The electrically insulating shell 1150 defines a hole 1160 therethrough. A post 1170 formed of an electrically conductive material extends through the hole 1160 and the passage 1130. The post 1170 contacts the first lead 1030 to form a second electrical contact.

FIG. 12 is an exploded view of a cartridge including the heating element of FIG. 10 according to at least one example embodiment.

In at least one example embodiment, as shown in FIG. 12, instead of the first lead 1030 and the second lead 1040 contacting the post 1170 and protrusion 1125, the cartridge may include a support 1260 and two side-by-side electrically conductive posts 1220, 1230. The posts 1220, 1230 are electrically insulated from each other, and may be molded into the support 1260 in some example embodiments. Moreover, the heating element 1010 may abut transfer material 725, which may abut a gasket 1200 having weep holes 1210 therein. The gasket 1200 defines a portion of the reservoir, and pre-vapor formulation from the reservoir may flow through the weep holes 1210 in at least one example embodiment.

FIG. 13 is a perspective view of a heater assembly according to at least one example embodiment.

In at least one example embodiment, as shown in FIG. 13, one or more features of the heating element 1310 are generally the same as in FIG. 11 and the first lead 1330 extends inwardly from the heating element 1310 and is not planar with the heating element 1310, the second lead 1340 has a generally L-shape, the post 1170 is shorter than the post of FIG. 11, and air channels 1300 are defined in sides of the support 1350, such that air may flow between the support 1350 and an inner surface of a housing 300 of a cartridge 220. In addition, a second electrical contact (not shown) may be overmolded in the support 1350, such that the second lead 1340 contacts the second electrical contact when the heating element 1310 is placed on the support 1350.

FIG. 14 is a perspective view of a heater assembly according to at least one example embodiment.

In at least one example embodiment, as shown in FIG. 13, one or more features of the heating element 1410 are generally the same as in FIG. 11, and the first contact 1430 has a generally spiral shape and the second lead 1430 has a generally L-shape. The tip portions 1450 of the heating element 1410 rest on a top surface of the support 1350.

In other example embodiments, not shown, the heating element 10 may be reduced in size, such that tips of the heating element 10 are not supported by a support.

Example embodiments having thus been described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the intended spirit and scope of example embodiments, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.

Claims

1. A heater assembly comprising: a heating element including, a planar portion including a filament, the filament defining an air channel through the planar portion, the filament arranged so as to form a plurality of curves, each of the curves having a closed end, an open end, and a tip extending away from the air channel thereon, the tip of each of the curves extending from the closed end thereof,an elongated body extending outwardly from the tip of each of the curves, the elongated body extending perpendicular to a width of the tip, and a width of the elongated body being greater than the width of the tip,a first lead portion, anda second lead portion, at least one of the first lead portion, the second lead portion, or both the first lead portion and the second lead portion being coplanar with the planar portion of the heating element; anda support, the heating element in contact with the support such that the tip of each one of the curves rests thereon.

2. The heater assembly of claim 1, wherein at least one of the curves has a capital letter omega shape.

3. The heater assembly of claim 1, wherein at least one of the curves has a U-shape.

4. The heater assembly of claim 1, wherein the filament defines the air channel through a central area of the planar portion.

5. The heater assembly of claim 1, wherein the open end of each of the curves is adjacent the air channel.

6. The heater assembly of claim 1, wherein the filament includes stainless steel.

7. The heater assembly of claim 1, wherein the filament follows a circuitous path.

8. The heater assembly of claim 7, wherein a width of the filament varies along the circuitous path.

9. The heater assembly of claim 1, wherein a width of the filament gradually increases in a direction away from the air channel.

10. The heater assembly of claim 1, wherein the first lead portion extends into the air channel and the second lead portion extends away from the air channel.

11. The heater assembly of claim 1, wherein the first lead portion and the second lead portion extend away from the air channel.

12. The heater assembly of claim 1, wherein the support includes a support ring.

13. The heater assembly of claim 12, wherein the support ring is formed of one or more materials including polyetheretherketone.

14. The heater assembly of claim 12, wherein the support ring includes at least one electrical contact molded within the support ring.

15. The heater assembly of claim 1, wherein the elongated body of each of the curves has a trapezoidal shape.

16. The heater assembly of claim 1, wherein the elongated body of each of the curves has a rectangular shape.

17. The heater assembly of claim 1, at least one of the first lead portion, the second lead portion, or both the first lead portion and the second lead portion having a spiral shape.

18. The heater assembly of claim 1, at least one of the first lead portion, the second lead portion, or both the first lead portion and the second lead portion having a L-shape.

19. The heater assembly of claim 1, wherein the filament surrounds the air channel.

20. A cartridge for an e-vapor device, comprising: a housing;a reservoir in the housing;a transfer material adjacent a portion of the reservoir; anda heater assembly including, a heating element, the heating element including, a planar portion including a filament, the filament defining an air channel through the planar portion, the filament arranged so as to form a plurality of curves, each of the curves having a closed end, an open end, and a tip extending away from the air channel thereon, the tip of each of the curves extending from the closed end thereof,an elongated body extending outwardly from the tip of each of the curves, the elongated body extending perpendicular to a width of the tip, and a width of the elongated body being greater than the width of the tip,a first lead portion, anda second lead portion, at least one of the first lead portion, the second lead portion, or both the first lead portion and the second lead portion being coplanar with the planar portion of the heating element;and a support, the heating element in contact with the support such that the tip of each of the curves rests thereon.

21. The cartridge of claim 20, wherein the planar portion, the first lead portion, and the second lead portion are a unitary body.

22. The cartridge of claim 20, further comprising: an inner tube within the housing, the inner tube defining an airway through the housing, and an outer surface of the inner tube and an inner surface of the housing at least partially defining the portion of the reservoir.

23. The cartridge of claim 20, wherein the filament includes stainless steel.

24. The cartridge of claim 20, wherein the filament follows a circuitous path.

25. The cartridge of claim 24, wherein a width of the filament varies along the circuitous path.

26. The cartridge of claim 20, wherein a width of the filament gradually increases in a direction away from the air channel.

27. The cartridge of claim 20, wherein the first lead portion extends into the air channel and the second lead portion extends away from the air channel.

28. The cartridge of claim 20, wherein the first lead portion and the second lead portion extend away from the air channel.

29. The cartridge of claim 20, wherein the support includes a support ring.

30. The cartridge of claim 29, wherein the support ring is formed of one or more materials including polyetheretherketone.

31. The cartridge of claim 29, wherein the support ring includes at least one electrical contact molded within the support ring.

32. The cartridge of claim 20, wherein the elongated body of each of the curves has a trapezoidal shape.

33. The cartridge of claim 20, wherein the elongated body of each of the curves has a rectangular shape.

34. The cartridge of claim 20, at least one of the first lead portion, the second lead portion, or both the first lead portion and the second lead portion having a spiral shape.

35. The cartridge of claim 20, at least one of the first lead portion, the second lead portion, or both the first lead portion and the second lead portion having a L-shape.

36. The cartridge of claim 20, wherein the support is a cylindrical wall having a top edge, and wherein the tip of at least one of the curves rests on the top edge of the cylindrical wall.

37. The cartridge of claim 20, wherein at least one of the curves has a capital letter omega shape.

38. The cartridge of claim 20, wherein at least one of the curves has a U-shape.

39. The cartridge of claim 20, wherein the heating element is in contact with the transfer material.