Free ink writing instrument with microfluidic valve

Abstract

A writing instrument including a main body provided with a writing tip. The writing tip being supplied with ink by a free ink-type reservoir equipped with a pressure regulating device for regulating the pressure within the reservoir. The pressure regulating device includes at least one microfluidic valve.

Claims

1. A writing instrument comprising: a main body provided with a writing tip, the writing tip being supplied with ink by a free-ink reservoir, the free-ink reservoir being provided with a pressure regulating device for regulating the pressure within the free-ink reservoir, the pressure regulating device including at least one microfluidic valve arranged in a gas circuit disposed between an inside and an outside of the free-ink reservoir, wherein the microfluidic valve includes an inlet chamber, an outlet chamber and a regulating chamber, the inlet chamber and the outlet chamber being adjacent and separated by a wall, the wall having a projection that extends towards an inside of the inlet chamber.

2. The writing instrument according to claim 1, wherein the microfluidic valve is separated from the inside of the reservoir by an element that is permeable to gases and impermeable to liquids.

3. The writing instrument according to claim 1, wherein the microfluidic valve includes a section arranged on the inside of the reservoir, the section including a non-wettable coating.

4. The writing instrument according to claim 1, further including a detachable cap configured to cover and protect the writing tip in a protection position, the cap covering a protected portion of the main body in the protection position, the microfluidic valve including at least one channel that opens into the outside of the main body, the channel opening being in a portion of the main body that is separate from the protected portion.

5. The writing instrument according to claim 1, wherein the at least one microfluidic valve includes only one microfluidic valve.

6. The writing instrument according to claim 5, wherein the at least one microfluidic valve includes a bidirectional microfluidic-valve unit.

7. The writing instrument according to claim 1, wherein the at least one microfluidic valve includes a plurality of microfluidic valves, the reservoir extending in an axial direction and a circumferential direction, the microfluidic valves being distributed in the axial direction and/or the circumferential direction of the reservoir.

8. The writing instrument according to claim 1, wherein the pressure regulating device includes a baffle and/or a porous or fibrous element, the at least one microfluidic valve being unidirectional.

9. A writing instrument comprising: a main body including with a writing tip and a detachable cap configured to protect the writing tip in a protection position, the writing tip being supplied with ink by a free-ink reservoir, the reservoir being provided with a pressure regulating device for regulating a pressure within the reservoir, the pressure regulating device including a baffle and/or a porous or fibrous element, the cap being provided with at least one microfluidic valve for regulating a pressure inside the cap in the protection position, wherein the microfluidic valve includes an inlet chamber, an outlet chamber and a regulating chamber, the inlet chamber and the outlet chamber being adjacent and separated by a wall, the wall having a projection that extends towards an inside of the inlet chamber.

10. The writing instrument according to claim 9, wherein the microfluidic valve is separated from the inside of the reservoir by an element that is permeable to gases and impermeable to liquids.

11. The writing instrument according to claim 9, wherein the microfluidic valve includes a section arranged on the inside of the reservoir, the section including a non-wettable coating.

12. The writing instrument according to claim 9, further including a detachable cap configured to cover and protect the writing tip in a protection position, the cap covering a protected portion of the main body in the protection position, the microfluidic valve including at least one channel that opens into the outside of the main body, the channel opening being in a portion of the main body that is separate from the protected portion.

13. The writing instrument according to claim 9, wherein the at least one microfluidic valve includes only one microfluidic valve.

14. The writing instrument according to claim 13, wherein the at least one microfluidic valve includes a bidirectional microfluidic-valve unit.

15. The writing instrument according to claim 9, wherein the at least one microfluidic valve includes a plurality of microfluidic valves, the reservoir extending in an axial direction and a circumferential direction, the microfluidic valves being distributed in the axial direction and/or the circumferential direction of the reservoir.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The disclosure and its advantages will be better understood upon reading the following detailed description of various embodiments given by way of non-limiting example. The description refers to the accompanying pages of drawings, in which:

(2) FIG. 1 shows a first embodiment of a writing instrument,

(3) FIG. 2A shows a bidirectional microfluidic-valve unit according to the magnification IIA in FIG. 1,

(4) FIGS. 2B and 2C show two separate states of the bidirectional microfluidic-valve unit, and FIG. 2D is a sectional view along plane IID in FIG. 2A,

(5) FIG. 3 shows a second embodiment of the writing instrument,

(6) FIG. 4 shows a third embodiment of the writing instrument,

(7) FIG. 5 shows a fourth embodiment of the writing instrument,

(8) FIG. 6 shows a fifth embodiment of the writing instrument, and

(9) FIG. 7 shows a sixth embodiment of the writing instrument.

DETAILED DESCRIPTION

(10) FIG. 1 shows a first embodiment of a writing instrument 10. The writing instrument 10 comprises a main body 12 provided with a writing tip 14. In this embodiment, the main body 12 has an inner cavity and forms a free-ink reservoir 12 in which the ink 13 is free to move. Although the main body and the reservoir are formed by the same part in this embodiment, the main body and the reservoir may be formed by two separate parts in a variant.

(11) The reservoir 12 is provided with a pressure regulating device 16 for regulating the pressure within the reservoir 12. In this embodiment, the pressure regulating device 16 comprises a single bidirectional microfluidic-valve unit 18.

(12) It is noted that the reservoir 12 extends in an axial direction X and a circumferential direction C. The writing tip 14 is arranged at a first end 12A in the axial direction X of the reservoir 12. In this embodiment, the bidirectional microfluidic-valve unit 18 is arranged at the second end of the reservoir 12, opposite the first end in the axial direction. The second end 12B is formed by a stopper 13 that is sealingly fastened, by welding in this embodiment, to the tubular portion 12C of the reservoir 12. A configuration of this kind makes it possible to reduce manufacturing costs, only the cap 13 being provided with a bidirectional microfluidic-valve unit 18.

(13) The writing instrument 10 also comprises a detachable cap 20, which is shown in a protection position of the tip 14 in FIG. 1. In the position, the cap 20 covers a portion of the main body 12, the portion forming a “protected” portion. The below-described channels of the bidirectional microfluidic-valve unit 18, which open into the outside of the reservoir 12, open thereinto in a portion separate from the portion protected by the cap 20.

(14) In general, it is noted that the bidirectional microfluidic-valve units 18 are shown symbolically in FIGS. 1, 3, 4 and 5, while the bidirectional microfluidic-valve units 18 are shown as schematic diagrams in FIGS. 2A, 2B and 2C.

(15) More specifically, FIGS. 2A, 2B and 2B show a bidirectional valve comprising two different entities 18A and 18B. In general, if the valve comprises only a plurality of similar entities, the valve is to be unidirectional. If the valve comprises two different types of entities, as shown in FIGS. 2A, 2B and 2C, the valve is to be bidirectional. A bidirectional microfluidic-valve unit comprises one or more bidirectional valves (for example, the valve shown in FIGS. 2A, 2B and 2C), two unidirectional valves of which the possible fluid flow directions are opposite, or a combination of bidirectional valves and unidirectional valves.

(16) The bidirectional microfluidic-valve unit 18 will now be described in more detail with reference to FIGS. 2A, 2B and 2C.

(17) It is noted that in this embodiment, the entities 18A and 18B have substantially the same structure having three chambers 19A, 19B and 19C, a membrane 23 fluidically separating the chambers by default (position shown in FIG. 2A), the chambers each being connected to a channel. In each entity, the chamber 19A forms an inlet chamber 19A, through which the gas enters in the event of pressure regulation via a channel 21A. In the entity 18A, the channel 21A opens towards the inside of the reservoir, while the channel 21A opens towards the outside of the reservoir in the entity 18B. The chamber 19B forms a regulating chamber 19B in fluidic communication with the outside through a channel 21BA, which is a reference environment for the regulation of the pressure inside the reservoir. The chamber 19C forms an outlet chamber 19C, through which the gas escapes in the event of pressure regulation via a channel 21C. In the entity 18A, the channel 21C opens towards the outside of the reservoir, while the channel 21C opens towards the inside of the reservoir in the entity 18B.

(18) In this embodiment, in each entity 18A and 18B, the inlet and outlet chambers 19A and 19C are adjacent and separated by a wall 24, while the chamber 19B faces the chambers 19A and 19B and opens into the chambers 19A and 19B. To fluidically separate the chambers, the membrane 23 is arranged between the chambers 19A and 19C and the chamber 19B. The membrane 23 abuttingly interacts with the wall 24.

(19) FIG. 2D shows the shape of the wall 24 in a transverse sectional view in parallel with the membrane. In each entity 18A and 18B, the wall 24 has a projection 24A extending towards the inside of the inlet chamber 19A. In this embodiment, the projection has the shape of a projecting ridge, the angle α of the ridge being between 45° and 120°, for example. In this embodiment, the projection 24A extends over the entire height H of the wall 24 (see FIG. 2A). In this embodiment, the sides of the walls 24 on the outlet chamber 19C side do not have a projection, but could, according to a variant, also have a projection that is similar or not similar to the projection 24A.

(20) An element 22 that is permeable to gases and impermeable to liquids is arranged on the bidirectional microfluidic-valve unit 18, on the inside of the reservoir 12, and separates the unit from the inside of the reservoir. Furthermore, in this embodiment, the walls of the channels 21A and 21BB that open into the inside of the reservoir 12 comprise a non-wettable coating (not shown).

(21) The entity 18A makes it possible to avoid positive pressure within the reservoir 12 and places the inside and the outside of the reservoir in fluidic communication if the difference between the pressure Pint inside the reservoir 12 and the pressure Pext outside the reservoir 12 exceeds a first predetermined threshold value ΔP1 (i.e. a predetermined positive-pressure opening threshold for the difference in pressure between the outside and the inside of the reservoir). The membrane 23 of the entity 18A will thus be understood to be configured to move so as to place the inlet chamber 19A and the outlet chamber 19C in fluidic communication if Pint−Pext>ΔP1, as shown in FIG. 2B. In this embodiment, ΔP1=25 mbars. Of course, in general, ΔP1 is a positive or zero value.

(22) The entity 18B makes it possible to avoid excessive negative pressure within the reservoir 12 and places the inside and the outside of the reservoir 12 in fluidic communication if the difference between the pressure Pext outside the reservoir 12 and the pressure Pint inside the reservoir 12 falls below a second predetermined threshold value ΔP2 (i.e. a predetermined negative-pressure opening threshold for the difference in pressure between the outside and the inside of the reservoir). The membrane 23 of the entity 18B will thus be understood to be configured to move so as to place the chamber 19A and the chamber 19C in fluidic communication if Pext−Pint>ΔP2, as shown in FIG. 2C. In this embodiment, ΔP2=25 mbars. Of course, in general, ΔP2 is a positive or zero value. In this embodiment, ΔP1=ΔP2, but the threshold values may of course be different.

(23) FIGS. 3, 4 and 5 are other embodiments of the writing instrument, which differ from the writing instrument 10 in FIG. 1 merely in the number and the arrangement of the bidirectional microfluidic-valve units.

(24) The second embodiment of the writing instrument 10′ in FIG. 3 comprises a plurality of bidirectional microfluidic-valve units 18 evenly distributed in the axial direction X of the reservoir 12. For example, each bidirectional microfluidic-valve unit 18 is spaced apart from the adjacent bidirectional microfluidic-valve units 18 by 1 cm (one centimeter) in the axial direction X.

(25) The third embodiment of the writing instrument 10″ in FIG. 4 comprises a plurality of bidirectional microfluidic-valve units 18 evenly distributed in the circumferential direction C of the reservoir 12. For example, each bidirectional microfluidic-valve unit 18 is spaced apart from the adjacent bidirectional microfluidic-valve units 18 by 36° in the circumferential direction C, around the axis X of the reservoir 12.

(26) The fourth embodiment of the writing instrument 10′″ in FIG. 5 comprises a plurality of bidirectional microfluidic-valve units 18 evenly distributed in the circumferential direction C and in the axial direction X of the reservoir 12. In this embodiment, the bidirectional microfluidic-valve units 18 are distributed in a helical coil around the axis X of the reservoir 12. For example, each bidirectional microfluidic-valve unit 18 is spaced apart from the adjacent bidirectional microfluidic-valve units 18 by 36° in the circumferential direction C, around the axis X of the reservoir 12, and by 1 cm in the axial direction X.

(27) FIG. 6 shows a fifth embodiment of the writing instrument 10″″ in which, in comparison with the writing instrument 10 in FIG. 1, the pressure regulating device 16 of the reservoir 12 comprises a baffle 26 and a unidirectional microfluidic valve 18′. For example, the microfluidic valve 18′ makes it possible to avoid positive pressure inside the reservoir 12. For example, the microfluidic valve 18′ only comprises entities of the type 18A in FIG. 2A. In other words, in this embodiment, the microfluidic valve 18′ is a “positive pressure” valve. This makes it possible to avoid ink leakage in the event of positive pressure inside the reservoir in relation to the outside of the reservoir, even if the cap 20 is closed. In a variant, the regulating device 16 comprises, in addition to or in place of the baffle 26, a porous or fibrous element (not shown). Of course, the unidirectional microfluidic valve 18′ could make it possible to avoid excessive negative pressure inside the reservoir 12 and only comprise entities of the type 18B in FIG. 2A. The microfluidic valve 18′ would thus be to be a “negative pressure” valve. At the same time, a configuration of this kind only makes it possible to avoid excessive negative pressure within the reservoir 12, which hampers only the supply of ink to the writing tip, which is not critical since the cap is closed (and thus the user is not using the writing instrument), but not to avoid ink leakage in the event of positive pressure inside the reservoir in relation to the outside of the reservoir when the cap 20 is closed.

(28) It will thus be understood that the pressure regulating device 16 of the reservoir 12 in the first, second, third and fourth embodiments in FIGS. 1, 3, 4 and 5 comprises only one microfluidic valve, while the pressure regulating device 16 of the reservoir 12 in the fifth embodiment in FIG. 6 comprises a combination of at least one microfluidic valve and another separate device, namely a baffle, a fibrous element and/or a porous element.

(29) FIG. 7 shows a sixth embodiment of the writing instrument 10′″″ in which, in comparison with the writing instrument 10 in FIG. 1, the pressure regulating device 16 of the reservoir 12 comprises a baffle 26 but not a microfluidic valve. The cap 20 is provided with a microfluidic valve, in this embodiment a bidirectional microfluidic-valve unit 18 for regulating the pressure between the inside and the outside of the cap 20 when the cap is protecting the writing tip 14 (position shown in FIG. 7). In this way, owing to the bidirectional microfluidic-valve unit 18 of the cap 20, the baffle 26 can regulate the pressure within the reservoir 12 even when the cap 20 is protecting the writing tip 14. Of course, in a variant, the regulating device 16 of the reservoir 12 comprises, in addition to or in place of the baffle 26, a porous or fibrous element (not shown).

(30) Although the present disclosure has been described with reference to specific embodiments, it is evident that it is possible to make modifications and changes to the embodiments without departing from the general scope of the disclosure as defined by the claims. In particular, individual features of the various embodiments illustrated/shown may be combined in additional embodiments. Consequently, the description and drawings should be considered to be illustrative rather than limiting.