Device and needle module for skin puncture - Patent application

Abstract

a reciprocating skin puncture needle module comprising a needle unit, a housing and a biasing mechanism, the needle unit comprising a needle, the needle unit movable relative to the housing between an extended position in which a distal end of the needle extends from the distal end of the housing and a retracted position in which the distal end of the needle is disposed within the housing, the biasing mechanism being arranged to bias the needle unit towards the retracted position, the needle module further comprising a limiting mechanism being arranged to limit relative movement of the needle unit out of the distal end of the housing to a maximum extended distance upon movement towards the extended position, the maximum extended distance being 1.5 mm or less; [Selected Figure] Figure 2A

Description

[Technical Field]

[0001] The present invention relates to a skin-piercing needle module and a device comprising the skin-piercing needle module.The present invention further relates to a method for introducing ink into human skin.

[0002] In radiation therapy, or simply radiotherapy, patients are typically irradiated locally with beams of radiation to control or kill malignant cells. It is important that these beams are directed as precisely as possible to the target, on the one hand to ensure optimal treatment of these malignant cells, and on the other hand to minimize damage to surrounding tissues due to the delivery of the radiation beam.

[0003] To properly guide a radiation beam to tissue as planned preoperatively, it is known to apply small skin marks to the patient that can be used to automatically guide and align the beam as planned, for example, based on a CT scan of the patient. Because radiation therapy typically involves repeatedly delivering radiation beams to a target over an extended period of time, sometimes over several months, these marks must be maintained throughout the treatment period to ensure continued proper alignment. To this end, it is known to introduce ink into the patient's skin as skin marks.

[0004] Typically, a small knife or scalpel is used to make these marks. The knife is dipped in ink and then introduced into the patient's skin. This can be a painful process, especially in areas containing bony structures close to the body surface, such as the patient's rib cage. Furthermore, ink dipping is time-consuming and poses the risk of accidental ink dripping, as well as the risk of accidental puncture by the exposed knife.

[0005] Devices for introducing ink into the skin, such as reciprocating skin-piercing needle modules according to the preamble of claim 1, are known in this respect from the field of tattooing or permanent make-up, although permanent marks are usually not preferred by patients.

[0006] It is an object of the present invention, among other objects, to provide an improved and / or more efficient skin-piercing needle module in which at least one of the above-mentioned problems is at least partially alleviated. Summary of the Invention [Means for solving the problem]

[0007] This object, among other objects, is achieved by a device according to the appended claim 1. More particularly, this object, among other objects, is achieved by a reciprocating skin puncturing needle module comprising a needle unit, a housing and a biasing mechanism, the needle unit comprising a needle, said needle unit movable relative to said housing between an extended position in which a distal end of the needle extends from the distal end of said housing and a retracted position in which the distal end of the needle is disposed within the housing, the biasing mechanism arranged to bias the needle unit towards the retracted position, and the needle module comprising a limiting mechanism arranged to limit relative movement of the needle unit out of the distal end of the housing to a maximum extended distance upon movement towards the extended position, said maximum extended distance being no more than 1.5 mm.

[0008] According to the present invention, the needle unit is prevented from extending further from the housing than a maximum extension distance, thereby limiting the insertion depth of the needle unit, and more specifically the sharp distal end of the needle unit, in the patient's skin to the maximum extension distance. The maximum extension distance can therefore be defined as the maximum distance between the distal end of the needle unit and the distal end of the housing from which it preferably extends.

[0009] Preferably, the maximum extension distance is set to a distance such that the needle unit, and therefore the ink, is introduced only into the epidermis of the patient's skin. This would result in a non-permanent mark, except in the field of tattooing, where ink is introduced into tissues below the epidermis. However, it has been found that shallow marks such as those made using the needle module of the present invention are maintained long enough to allow continued proper alignment throughout the duration of radiation therapy.

[0010] The thickness of the skin layer may vary from patient to patient. Preferably, the maximum extension distance is 1.5 mm or less, even more preferably 1.2 mm or less, and even more preferably 1.0 mm or less. The lower limit is defined so that the ink is introduced deep enough into the skin, and may be, for example, 0.1 mm, preferably 0.2 mm. A preferred working range is between about 0.2 mm and about 0.8 mm.

[0011] Limiting the maximum extension further improves the safety of the needle module in use, which is of paramount importance in terms of safety and compliance with medical safety standards, outside of the fields of, for example, tattooing and permanent make-up.

[0012] According to a preferred embodiment, the limiting mechanism comprises cooperating stop surfaces for limiting the relative movement of the needle unit and the housing, thereby effectively blocking further movement of the needle unit from the housing beyond the maximum extension distance. An efficient limiting mechanism is obtained if protrusions and / or recesses are arranged on the inside of the housing for cooperating with protrusions arranged on the outside of the needle unit.

[0013] Typically, a needle module of the type according to the present invention is coupled to a drive device comprising a drive rod that is driven to reciprocate back and forth, for example by a suitable motor. Such drive rod then engages the needle unit, thereby urging it towards an extended position so that it extends from the housing. A biasing mechanism then retracts the needle unit into the housing, i.e. towards a retracted position, for biasing the needle unit back upon retraction of the drive rod.

[0014] The needle unit is preferably arranged to move only along the longitudinal axis relative to the housing. The linear reciprocating movement of the needle unit reduces pain when inserting the needle unit into the patient's skin. To guide the needle unit in linear movement, the stop surface is preferably substantially ring-shaped. For example, a ring-shaped stop surface can be arranged in the housing, through an opening through which the needle unit can be moved. The needle unit can then define a maximum extension distance by providing cooperating stop surfaces that abut against the annular stop surface of the housing. These stop surfaces, or more generally, limiting mechanisms, then guide the needle unit relative to the housing, ensuring linear movement between the extended and retracted positions.

[0015] The biasing mechanism, e.g., in the form of a spring or other elastic element, is preferably arranged to bias the needle unit back into the housing, e.g., toward the retracted position. The biasing mechanism may be arranged between the needle unit and the housing to induce such a biasing force. For example, if a spring is used as the biasing mechanism, such spring may be arranged between the needle unit and a suitable protrusion arranged on the housing. Alternatively, a elastic element, e.g., an elastic tubular member, may be fixed between the needle unit and the housing, such that movement of the needle unit toward the extended position causes the elastic member to stretch, thereby biasing the needle unit backward as it moves toward the retracted position.

[0016] According to a further preferred embodiment, the biasing mechanism engages the needle unit in a first position, and the needle unit is provided with a stop surface at a distance from said first position, whereby the biasing means and the limiting mechanism are separated and ensure the correct operation of both mechanisms independently.

[0017] Preferably, the limiting mechanism is arranged to limit the movement of the needle unit relative to the housing to a distance where the biasing mechanism has not yet reached its maximum relative movement. The biasing mechanism may, for example, comprise a spring, against which the drive rod of the drive element acts to move the needle unit out of the housing. The limiting mechanism is then preferably arranged so that the biasing mechanism has not yet reached its final limit. For example, in the case of a spring, there may still be room between the windings of the spring. In the case of another elastic element, the elastic element may not yet be stretched to its final elastic limit.

[0018] Alternatively, the maximum extension distance may be determined by the operating range of the biasing means. Thus, according to a further preferred embodiment, the limiting mechanism is at least partly formed by the biasing mechanism, which is arranged to limit the relative movement of the needle unit out of the distal end of the housing to said maximum extension distance. In this alternative, the maximum extension distance is determined by the biasing mechanism, i.e., the biasing mechanism limits the extension of the needle unit from the housing to the maximum extension distance. In other words, the biasing mechanism comprises or forms the limiting mechanism, so that in the extended position the biasing mechanism is in its final position.

[0019] According to a further preferred embodiment, the housing comprises a main housing part and a detachable distal housing part. Such a module is easy to manufacture. Preferably, the main housing part and the distal housing part can be interconnected using a suitable detachable interconnection, for example a snap-fit ​​connection. This allows the limiting mechanism to be preferably at least partly located in the main housing part. This prevents accidental loosening of the distal housing part.

[0020] To improve the guiding action as already mentioned above, it is preferred that the main housing is provided with a stop surface at or near its distal end, which improves the guiding action of the limiting mechanism as explained above and also reduces deflection of the more distal end of the needle unit as it guides the needle unit at its most distal part.

[0021] As mentioned above, safety plays an important role, especially in the field of medical devices. Any risks to use must be minimized in medical instruments such as the needle module according to the present invention. Thus, according to a further aspect of the present invention, in the retracted position, the proximal end of the needle extends within the housing. As mentioned above, in use, the proximal end of the needle unit is typically engaged by a drive rod of a drive device for pushing the distal end of the needle unit out of the housing. By providing a needle module whose proximal end is retained in the housing and preferably inaccessible by hand from outside the housing, accidental movement of the distal end of the needle unit out of the housing is prevented. This improves safety in the resting or retracted position when the device is not in use.

[0022] Preferably, the housing is substantially cylindrical and the needle unit is movable within said cylindrical housing. The housing preferably has a length greater than that of the needle unit so that the needle unit can be fully received within said housing. For example, the needle unit can only be moved out of the housing upon coupling with a drive device comprising a suitable drive rod that can be received in a proximal opening of the housing.

[0023] By limiting the maximum extension of the distal end of the needle unit on the one hand, and by ensuring that in the retracted position the proximal end of the needle extends into the housing to prevent accidental punctures on the other hand, a needle unit that is safe to use is obtained. However, it should be mentioned that retention of the proximal end of the needle unit in the housing may also be applied to needle modules without such a limiting mechanism or by a limiting mechanism allowing a greater displacement than described above.

[0024] According to a preferred embodiment, a limiting mechanism is further arranged to limit displacement of the proximal end of the needle in the retracted position, so that the proximal end of the needle is retained within the housing. A suitable cooperating protrusion may again be provided to prevent proximal movement of the needle unit from the housing. Again, distal movement may be limited by biasing means. A biasing mechanism may be further arranged here to retain the proximal end of the needle within the housing.

[0025] Applying skin marks using, for example, a knife as described above is time-consuming because it takes time to dip the knife into a suitable coloring agent, such as ink. Furthermore, excess ink on the knife can cause ink stains. In needle modules used in the field of tattooing or permanent makeup, the needle unit may include multiple needles within the needle unit. While using such a configuration reduces the risk of dripping, it is still time-consuming to dip the needle module, and particularly the distal end of the needle unit, into the coloring agent.

[0026] Therefore, in a further improved needle module according to the present invention, the housing comprises a reservoir containing a colorant, such as ink, to be introduced into the skin, eliminating the need to immerse the needle module in ink as the colorant to be used is already available within the needle module, thereby further improving the skin marking process.

[0027] A colorant, or simply ink, is a chemical suitable for introduction onto human or animal skin. Preferably, the colorant is non-toxic and / or dermatologically neutral.

[0028] Preferably the reservoir contains less than 0.3 ml, more preferably less than 0.1 ml of colorant, which is sufficient to produce the required skin marking, for example outside the field of tattooing or permanent make-up.

[0029] The reservoir is arranged to cooperate with the needle unit, particularly the distal end of the needle unit, so that the coloring agent can be introduced into the patient's skin. For this purpose, the reservoir is preferably arranged at or near the distal end of the housing. When a two-piece housing for the needle module is used, comprising a proximal main housing portion and a detachable distal housing portion, it is preferred that the distal housing portion comprises the reservoir. The distal housing portion comprising the reservoir can then be efficiently manufactured or replaced as needed.

[0030] A reservoir extending at or near the distal end of the housing can be used to efficiently transfer colorant to the distal end of the needle unit, for example, via capillary force. To improve the transfer of colorant to the distal end of the needle unit, according to a further preferred embodiment, the distal end of the needle unit is preferably reciprocally movable between a position close to the reservoir and a position distant from the reservoir when moving between the retracted and extended positions. At the position close to the reservoir, colorant can be transferred to the distal end, for example, via capillary force, while at the position distant from the reservoir or extended position, the ink can be transferred to the skin. Colorant transfer is further improved if the distal end of the needle unit is reciprocally movable in and out of the reservoir when moving between the retracted and extended positions. Thus, in use, when driven by a suitable drive device, the distal end moves back and forth between a position within the reservoir, which allows for efficient ink uptake, and a position where the distal end extends from the housing to introduce the ink to the patient's skin.

[0031] According to a further preferred embodiment, the distal end of the needle unit extends a proximal distance from the reservoir in the retracted position, the needle unit then being at a distance from the reservoir to prevent the colorant from spilling out.

[0032] When the needle module is in use, the module is typically coupled to a drive device having a reciprocating drive rod. According to a further preferred embodiment, when the needle module is coupled to the drive device, the needle unit is movable to an intermediate position, the intermediate position being between the extended position and the retracted position, and the needle unit extends into the reservoir. When the needle module is coupled, the needle unit, preferably the distal end of the needle unit, moves distally and is received in the reservoir. Thus, coloring agent can be transferred to the needle unit before use. Then, during use, the needle unit moves back and forth between the intermediate position and the extended position.

[0033] Preferably, the reservoir is held by the housing. The reservoir may be formed, for example, by two films, and may hold a coloring agent therebetween. The films may be punctured by the distal end of the needle unit before use. Preferably, the housing further includes a first film disposed near the distal end of the housing and a second film disposed further away from the distal end, with the reservoir disposed between the first and second films.

[0034] It should be noted that the use of a reservoir within the housing still provides safety benefits, but the elimination of the need for a separate ink immersion also helps to improve the safety of the device, as do the aspects of the restrictor mechanism and the proximal end of the needle unit within the housing, which may also be applied to the needle module itself, for example as specified in the preamble.

[0035] According to a further preferred embodiment, the reservoir comprises a cartridge for holding the colorant, the cartridge being puncturable by a needle, and the housing is arranged to hold the cartridge. Providing the colorant in the cartridge results in a simpler assembly process during assembly of the needle module, since there is no need to work with a separate fluid, which could lead to spillage or contamination. The cartridge can therefore be processed in a similar manner to processing the remaining needle module parts or components during assembly. Preferably, the cartridge is a removable cartridge. This allows for easy replacement of the cartridge in the needle module, for example, by replacing it with a cartridge containing a different type of colorant or a cartridge containing a different colored colorant.

[0036] The limiting mechanism is arranged to limit the maximum extension of the needle from the housing. However, typically, the drive device, which may include a drive rod for reciprocating the needle unit, is arranged only to reciprocate between a predetermined maximum value. Accordingly, a further preferred embodiment of the device further includes a separation mechanism for reciprocating the needle unit between the retracted position and the extended position, the separation mechanism having a first end arranged to be reciprocated and a second end arranged to drive the needle unit, the first end and the second end being movable relative to each other, the first end being reciprocally movable with a first displacement amplitude, and the second end being movable with a second displacement amplitude less than the first displacement amplitude. The separation mechanism is thereby arranged to allow at least partially decoupled movement of the needle unit relative to the driven end of the separation mechanism, such that when movement of the needle unit is inhibited or blocked by the limiting mechanism, the separation element is arranged to absorb the reciprocating motion applied to the driven end of the separation mechanism.

[0037] Preferably, the separation mechanism further comprises a biasing means arranged to bias the first end and the second end apart, and / or the separation mechanism comprises a first part including the first end and a second part including the second end, the first part and the second part being movable relative to each other, and the biasing means arranged between the first part and the second part to bias the first and second parts apart. The biasing means thereby ensures that the first part and the second part move synchronously together when the movement of the second end, and therefore the second part, is not blocked by a limiting mechanism or other blocking means. Therefore, a drive mechanism such as a reciprocating linear motor having a single stroke length can be used to drive a needle unit with a smaller stroke length.

[0038] The detachment mechanism is provided on the needle module, and according to a further preferred embodiment, a first end of the detachment mechanism is arranged to cooperate with a drive rod of a drive device. This allows the needle module to be driven using a simple drive device without a detachment unit, such as those used in tattooing, and allows the maximum extension distance of the needle distal end to be set independently of the reciprocating stroke length of the drive device. The drive rod then drives the first end of the detachment mechanism, which is provided as part of the needle module.

[0039] The present invention further relates to a skin puncturing device comprising a drive device according to the present invention and a needle module, the drive device comprising a motor for reciprocatingly driving a drive rod that reciprocates the needle unit. The drive device is preferably arranged to engage the proximal end of the needle unit and may be held within the housing as described above. The drive device is therefore shaped accordingly, allowing the needle to be continuously reciprocated for an extended period of time.

[0040] When the ink reservoir is located in the housing of the needle module, particularly at its distal end, it is preferred that the needle module be arranged so that attachment of the needle module to the drive device moves the distal end of the needle to an intermediate position. More preferably, the needle module is arranged to move the distal end of the needle between the intermediate position and the extended position. As mentioned above, this allows for efficient ink uptake from the reservoir.

[0041] The motor is then preferably coupled to the needle unit via a separation mechanism disposed between the motor and the drive rod, with the second end receiving the drive rod. As noted above, this allows for the use of a drive device comprising a motor and / or drive mechanism to generate reciprocating motion with a single stroke length. More preferably, the detachment mechanism is provided on the drive device. Providing the detachment mechanism on the drive device allows for simpler needle modules to be used. Because the needle modules are single-use items, the cost and effort of manufacturing these disposable needle modules is reduced.

[0042] In a further preferred embodiment, the limiting mechanism is at least partially provided on the needle module and partially provided on another part of the device, different from the needle module, and is arranged so that when the needle module is in a coupled state with the drive device, the maximum extension distance is less than the maximum extension distance of the needle module in a non-coupled state. Thus, the limiting mechanism is composed of different cooperating components located on different modules and / or parts of the device, for example, a stop surface located on the needle module and a stop surface on another part of the device that is arranged to contact the stop surface on the needle module. This allows the maximum extension distance to be determined by the assembly of the different modules of the device, so that, for example, a standard needle module can be used with various drive devices to set the distance the needle can extend from the tip of the needle module housing. This allows only a single needle module of simple design to be required, which can be manufactured cheaply in large quantities.

[0043] A further preferred embodiment of the device according to the present invention further comprises a spacer for setting the extension position of the needle unit, the spacer being arranged between the drive device and the needle unit to adjust the relative position between the housing and the drive rod of the drive device. This allows fine adjustment of the extension position of the maximum extension of the distal end of the needle unit from the housing. Preferably, however, this maximum extension is limited by the limiting mechanism as described above. The spacer can then be further limited by introducing a separate component, i.e., a spacer, between the needle module and the drive device. This changes the relative position between the drive device and the needle module, and consequently the reciprocating stroke of the drive rod.

[0044] According to one aspect of the invention, the device includes a limiting mechanism that, when located on the needle module, results in an efficient and compact configuration. The needle module may include a stop surface cooperating therewith.

[0045] However, alternatively or additionally, the limiting mechanism may comprise cooperating stop surfaces disposed on the needle unit and spacer to limit the relative movement of the needle unit and housing. The maximum extension of the needle tip can thereby be determined by the location of the stop surfaces on the spacer. This allows a single needle module design to be used in combination with various spacers to set different maximum extension differences. This further reduces the amount of parts that need to be manufactured to tight, precise tolerances. For example, by forming the limiting mechanism on the combined spacer and needle module, the drive device itself has little effect on the precision with which the needle is permitted to extend from the tip of the housing at its maximum extension.

[0046] Preferably, the spacer is provided with a blocking surface comprising a stop surface that cooperates with a stop surface on the needle module to form a bayonet or similar type of form-lock connection between said spacer and said needle module, said blocking surface on the spacer further comprising a stop surface of a limiting mechanism for limiting relative movement between the needle unit and the housing. By using a blocking surface on the spacer not only to lock the needle module to the spacer, but also to use the same blocking surface as part of the limiting mechanism, the number of features that need to be machined on or in the spacer is reduced. This reduction in complexity not only clearly reduces manufacturing costs, but also eliminates elements of uncertainty that accumulate due to manufacturing variability, allowing for greater accuracy in setting the maximum extension distance of the distal tip of the needle.

[0047] In a further preferred embodiment, an outwardly extending protrusion is provided on the needle unit, and a guide is arranged on the housing to guide the outwardly extending protrusion, the outwardly extending protrusion comprising a stop surface of the needle unit. The needle unit according to this embodiment can be displaced within the housing of the needle module to a position where the stop surface contacts a mutually cooperating stop surface provided on a part of the device different from the needle module, and cannot extend any further. In this process, the protrusion is guided by the guide on the housing, ensuring smooth operation of the mechanism.

[0048] In a further preferred embodiment, the spacer includes an inner wall disposed on an inner periphery of the spacer near its distal end, and the blocking surface is provided on the inner wall. More preferably, the limiting mechanism includes the stop surface disposed on an outwardly extending protrusion of the needle unit and the blocking surface disposed on the inner wall of the spacer, and the blocking surface is positioned to abut against the stop surface when the needle distal tip is at its maximum extension distance. By controlling the position of this inner wall within the spacer relative to the spacer distal end, it is possible to control the needle extension distance. This limits the sources of uncertainty in the resulting extension distance to the dimensions of the inner wall relative to the spacer distal end, the length of the needle module housing, and the distance between the needle tip and the stop surface disposed on the needle unit.

[0049] In a preferred embodiment, the device is arranged so that the needle module, spacer and / or drive device can be interconnected by a bayonet connection, which allows for a reliable yet easy to use connection between the various components and typically does not require the use of tools or training to operate.

[0050] The bayonet coupling preferably includes a first locking means for locking the relative longitudinal movement of the interconnected needle module and spacer. The first locking means preferably includes a blocking surface on the spacer and a locking surface on the exterior of the needle module housing, the locking surface preferably being located on a portion of the housing that is adapted to be inserted into the spacer. It is even more preferable if the limiting mechanism and the first locking means include a blocking surface on the spacer. This allows the needle module and spacer to be reliably coupled together so that the spacer and needle module are in the same relative position relative to each other. Locking the relative movement between the needle module and spacer using the blocking surface on the spacer secures the two components in a known relative position in the same way, accurately determining the maximum extension distance of the needle tip.

[0051] In a further preferred embodiment, the bayonet connection includes a second locking means for locking the relative rotational movement of the interconnected needle module and spacer. Preferably, the second locking means includes a protrusion and / or recess on the exterior of the housing, a portion of the housing adapted to be inserted into the spacer, with a corresponding protrusion and / or recess on the interior of the spacer, arranged to form a snap-fit ​​connection. More preferably, the protrusion and / or recess on the exterior of the housing passes through the corresponding protrusion and / or recess on the interior of the spacer to lock or unlock the snap-fit ​​connection, causing at least one of the housing and the spacer to deform to allow passage. This minimizes the risk of accidentally loosening the bayonet connection, which could result in the needle module being disengaged from the spacer or reducing the accuracy of setting the maximum needle tip extension. A snap-fit ​​connection has the advantage of being easy to open and close, creating a reliable connection. Furthermore, it produces a "click" sound when locked, allowing the operator to confirm that the connection is secure.

[0052] According to a further preferred embodiment, the device consists of non-magnetic components. This applies to the needle module itself, any spacers, any drive devices, and their respective components. This allows the device to be used in the vicinity of scanners, such as MRI scanners. Preferably, the device does not contain (ferromagnetic) magnetic materials, at least not to the extent that the device is unsuitable for use in the vicinity of, for example, an MRI scanner.

[0053] The needle can be made from a non-magnetic material, such as titanium or aluminum. Other components, such as the biasing mechanism, can also be made from this same material. Other components, such as the housing, can be made from plastic. The device preferably does not include electronic components. A suitable motor for the drive device is, for example, a pneumatic motor. Other non-electric motors can be used as well.

[0054] It should be noted that the aspects of interconnectivity of the various devices and modules by bayonet coupling, or the partial separation of the operation of the reciprocating drive from the needle unit by a separation device, and the spacers adjusting the relative position of the housing and the drive rod of the drive device, may also be applicable to the needle module itself or to a device comprising such a needle module, e.g. as specified by the preamble.

[0055] The present invention further relates to a kit of parts comprising the device, the needle module, and a plurality of spacers for setting various predetermined distances as described above, each spacer being arranged to define a different respective extended position. Preferably, the spacers have different lengths, e.g., by at least 0.1 mm, preferably at least 0.2 mm, more preferably at least 0.5 mm. In that case, the respective extended positions preferably vary from one another by at least 0.5 mm. The kit of parts also preferably comprises a drive device.

[0056] The present invention further relates to a method for introducing ink into human skin, in particular for skin marking a patient, - providing a device as described above; - providing a colorant; - driving the needle back and forth to pierce the human skin and depositing the coloring agent into the upper layer of the skin using the needle. [Brief explanation of the drawings]

[0057] The present invention is further illustrated by the following figures, which show preferred embodiments of the device and method according to the present invention and are not intended to limit the scope of the invention in any way. [Figure 1] FIG. 1 is a perspective view showing a schematic diagram of a needle module. [Figure 2a] 12A is a cross-sectional view of an embodiment of a needle module with the needle unit in a retracted position. FIG. [Figure 2b] FIG. 10 is a cross-sectional view of an embodiment of a needle module with the needle unit in an extended position. [Figure 3a] FIG. 10 is a cross-sectional view of another embodiment of a needle module with the needle unit in the retracted position. [Figure 3b] FIG. 10 is a cross-sectional view of another embodiment of a needle module with the needle unit in an intermediate position. [Figure 3c] FIG. 10 is a cross-sectional view of another embodiment of a needle module with the needle unit in an outer position. [Figure 4a] 13A-13C show another embodiment of a needle module. [Figure 4b] 13A-13C show another embodiment of a needle module. [Figure 4c] 13A-13C show another embodiment of a needle module. [Figure 4d] 13A-13C show another embodiment of a needle module. [Figure 5] FIG. 1 is a perspective view of an embodiment of a device comprising a needle module, a spacer, and a drive device. [Figure 6] FIG. 6 is a view of the embodiment of FIG. 5 showing the needle module and spacer in an exploded view. [Figure 7a] FIG. 10 is a cross-sectional view of an embodiment of a device prior to attachment of a needle module. [Figure 7b] FIG. 10 is a cross-sectional view of an embodiment of the device after needle module attachment, with the distal end of the needle in an intermediate position. [Figure 8a] FIG. 10 is a cross-sectional view of an embodiment in which the distal end of the needle is in an extended position. [Figure 8b] FIG. 10 is a cross-sectional view of an embodiment in which the distal end of the needle is in an extended position. [Figure 9a] 7A-7C show the spacers of FIGS. 5-7C. [Figure 9b] 7A-7C show the spacers of FIGS. 5-7C. [Figure 9c] 7A-7C show the spacers of FIGS. 5-7C. [Figure 10a] 10A-10C are cross-sectional views of an embodiment of the device in which the drive device comprises a motor, showing different points in the reciprocating cycle of the needle unit. [Figure 10b]10A-10C are cross-sectional views of an embodiment of the device in which the drive device comprises a motor, showing different points in the reciprocating cycle of the needle unit. [Figure 10c] 10A-10C are cross-sectional views of an embodiment of the device in which the drive device comprises a motor, showing different points in the reciprocating cycle of the needle unit. [Figure 11] 11 is a cross-sectional view showing the limiting mechanism according to the embodiment of FIG. 10 in more detail. DETAILED DESCRIPTION OF THE INVENTION

[0058] FIG. 1 shows a needle module 1 for coupling to an actuation device (not shown), such as a tattoo gun or permanent makeup device. The needle module 1 comprises a substantially cylindrical housing 10, in this example. The housing 10 comprises an open proximal end 10b (see also the cross-sectional views of FIGS. 2a and 2b) and an open distal end 10a. The proximal end 10b is arranged to couple with an actuation device (as described in connection with FIGS. 3a-3c) and, in this example, comprises a region of reduced diameter 13 thereat. A step 13a can act as a stop surface to determine the relative position of the coupled actuation device and the needle module 1. In this example, the housing 10 is further formed by two separate housing parts 11 and 12. The distal housing part 12 is provided with a tapered distal end 10a and can be coupled to the proximal main housing part 11 via a snap-fit ​​connection, generally indicated at 12a.

[0059] The needle unit 2 can be extended through the distal end 10a of the housing 10. The needle unit 2 (see FIG. 2a) includes a hard plastic needle base 23 in this example and a needle 21 at its distal end. The distal end 22 of the needle 21 is sharp. In this example, the needle unit 2 includes one needle 21. However, it is also possible to include multiple needles 21; see, for example, the embodiment in FIGS. 4a to 4d. The needle module 1 is arranged such that the needle unit 2 is reciprocally movable along the longitudinal direction L relative to the housing 10 between a retracted position (see FIG. 2a) in which the distal end 22 of the needle unit 2 extends into the housing 10, and an extended position (see FIGS. 1 and 2b) in which the distal end 22 of the needle unit 2 extends from the distal end 10a of the housing.

[0060] Movement of the needle unit 2 in the distal direction D from the housing 10 is induced by movement of a drive rod 32 (see, for example, FIG. 3b) of the drive device 3. The drive device 3 is arranged to reciprocate the drive rod 32 along the longitudinal direction Lb with a predetermined amplitude. Movement of the needle unit 2 back into the housing 10 is induced by a biasing mechanism 4, which in this example comprises a spring 41. The biasing mechanism 4 extends between the housing 10 and the needle unit and biases the needle unit 2 toward the retracted position. In this example, the spring 41 is arranged between a stop surface 11a of the housing 10 (formed on its inner surface in this example) and a stop surface of the needle unit 2 (in this example, the base 23 of the needle unit 2). The spring 41 biases the needle unit 2 proximally in direction P relative to the housing, i.e., toward the retracted position.

[0061] In the distal direction D, relative movement between the needle unit 2 and the housing 10 is limited by a limiting mechanism, in this example in the form of cooperating protrusions 11c and 23b on the housing 10 and the needle unit 2, respectively. The protrusions 11c and 23b abut at the location shown in FIG. 2b. In this example, the protrusion 11c is located on the inner wall of the housing 10, more specifically at the distal-most portion of the main housing portion 11. The protrusion 11c further serves to guide the needle unit 2 to move only in the longitudinal direction and is preferably ring-shaped or annular relative to the needle unit 2. The protrusion 23b of the needle unit 2 is located on a relatively rigid base 23. The limiting mechanism limits the extension of the needle unit 2 from the housing 10 to a maximum extension, shown schematically as distance d in the detail of FIG. 2b. Distance d is the distance between the distal end 22 of the needle unit 2 and the distal end 10a of the housing 10. In this example, the maximum extension is defined as 1.2 mm. This ensures that, in use, the needle tip 22 is inserted only into the patient's epidermis.

[0062] 2b, which shows the needle unit 2 in its most distal position, it can be seen that the spring 41 is not in a fully compressed position. Thus, the relative movement between the needle unit 2 and the housing 10 is not limited by the biasing mechanism. Alternatively, the biasing mechanism can form a limiting mechanism, in the sense that the final position of the biasing mechanism (e.g., the spring in a fully compressed state) limits the maximum extension, which, as mentioned above, is set to 1.2 mm in this example.

[0063] In the illustrated example, the protrusion 23b of the limiting mechanism formed on the needle unit 2 extends at a distance from the protrusion 23a that operates with the biasing mechanism. Thus, the biasing mechanism engages with the needle unit 2 in a first position, and the needle unit 2 has a stop surface 23b at a position spaced apart from said first position.

[0064] Movement of the needle unit 2 in the proximal direction P relative to the housing 10 is limited by a stop surface 11b, formed in this example by a separate plastic or rubber ring-shaped element 11b. The ring 11b further serves to guide the needle unit 2 so that it moves only in the longitudinal direction. In the retracted position shown in FIG. 2a, the needle unit 2 abuts the protrusion 11b of the housing 10 with the same protrusion 23a, which in this example works with the spring 41. From FIG. 2a, which shows the needle unit 2 in its most proximal position relative to the housing 10, it is clear that even in this retracted position, the proximal end 24 of the needle unit 2 is fully retained or received within the housing 10. In this example, the proximal end 24 extends at a distance from the proximal end 10b of the housing 10. Because the proximal end 24 extends into the housing 10, the proximal end 24 cannot be accidentally moved to the extended position, for example, by manual manipulation.

[0065] The embodiment shown in Figures 2a and 2b can be used to skin mark a patient by dipping the distal end 22 of the needle unit 2 into an ink reservoir (not shown) and subsequently applying the device to the patient. However, in the embodiment shown in Figures 3a to 3c, the needle module 1 comprises an ink reservoir 5 near the distal end 10a of the needle module 1. In this example, the ink reservoir 5 is located near the distal end 10a of the distal housing part 12. The reservoir 5 is formed by two films 51, 52 arranged at a distance from each other, between which a suitable ink 53 is placed for application to the patient's skin.

[0066] In the retracted position shown in FIG. 3a, the distal end 22 of the needle unit 2 extends a proximal distance from the reservoir 5. As shown, the needle unit 2 does not extend into the reservoir 5. Only when the needle module 1 is coupled to the drive device 3 is the needle unit 2 moved distally so that the needle unit 2 extends into the reservoir 5. This is shown in FIG. 3b. Ink 53 from the reservoir is transferred to the needle unit 2, and in particular to its distal end 22. In this example, the distal end 22 extends distally from the distal-most end of the reservoir (formed by the film 52 in this example), as shown in detail in FIG. 3b. However, it is also possible that in this position the distal end 22 of the needle unit 2 extends into the reservoir for efficient ink uptake.

[0067] Note that the drive device 3 includes a reciprocating drive rod 32 that can move between an intermediate position ( FIG. 3 b) and an outer position ( FIG. 3 c). When the drive device 3 is coupled, the needle unit 2 moves from the retracted position ( FIG. 3 a) to the intermediate position ( FIG. 3 b). In this position, the needle module 1 is ready for use. During use, the drive rod 32 is driven to reciprocate between the intermediate position ( FIG. 3 b) and the outer position ( FIG. 3 c). In the outer position of the drive rod 32, the needle unit 2 is biased distally such that the distal end 22 of the needle unit 2 protrudes from the distal end 10 a of the housing 10. Referring to FIG. 3 c, it can be seen that the limiting mechanism has not yet been activated, i.e., the protrusions 11 c and 23 b have not yet come into contact. The extension d2 of the distal end 22 of the needle unit 2 from the distal end 10 a of the housing 10 is determined, in this example, by the outer position of the drive rod 32, i.e., the amplitude of the drive rod 32. Distance d2 is less than distance d shown in Figure 2b, where the limiting mechanism of Figure 3c acts as a safety device to prevent the maximum extension from being exceeded.

[0068] The distance d2 is determined by the relative position of the needle module 1 and the drive device 3. This relative position can be adjusted by replacing the spacer 6 with a different spacer 6 having a different length e. The ring-shaped spacer 6 abuts against a step 13a provided on the housing 10 to ensure the proper relative position of the needle module 1 and the spacer 6. It should be understood that by placing a larger spacer 6 (in terms of length e), the distance d2 will decrease.

[0069] As an alternative to a spring 41 as a biasing mechanism, the embodiment of Figures 4a-4d includes a resilient element 42, as shown in Figure 4a, to bias the needle unit 2 back to the retracted position, where the proximal end 24 of the needle unit 2 is still retained within the housing 10.

[0070] Resilient element 42, in this example in the form of a resilient tube, is connected to housing 10 at the interconnection between distal housing portion 12 and proximal housing portion 11. The other end of resilient element 42 is connected to needle unit 2 at a distal location, in this example at the distal end of base portion 23. It will be appreciated that the resilient properties of element 42 bias needle unit 2 back from the position shown in Figure 4b to the position shown in Figure 4a.

[0071] Also in this embodiment, a limiting mechanism is provided in the form of cooperating protrusions 23a and 11c to limit the extension of the needle unit 2 from the distal end of the housing 10 to a maximum extension d (see detail in Figure 4b).

[0072] 4c and 4d, it should also be understood that when the needle module 1 is attached to the combination of the drive device 3 and the spacer 6, the needle unit 2 is urged into the ink reservoir 5. By driving the drive rod 32, the distal end 22 of the needle unit 2, which includes the plurality of needles 21, moves back and forth between an intermediate position (FIG. 4c) and an extended position (FIG. 4d). Again, in FIG. 4d, the protrusions 11c, 23a of the limiting mechanism have not yet abutted, so that the extension distance d2 is again less than the maximum distance d. The distance d2 is, in turn, determined by the length of the spacer 6.

[0073] FIG. 5 shows a perspective view of a further embodiment of a device 100, comprising a needle module 101, a spacer 102, and a drive device 103. The needle module comprises a distal housing part 104, at the tip 106 of which an opening 105 for the needle is arranged. A main housing part 107 is attached to the distal housing part 104 via a snap-fit ​​connection, whereby these two housing parts 104, 107 form the housing of the needle module. The main housing part 107 has a circular portion 108 and a rectangular portion 109. This shape of the main housing 107 corresponds to the interior space of the spacer 102, more specifically to the inner retaining wall 110 of the spacer. The inner retaining wall 110 comprises a protrusion arranged on a portion of the inner circumference of the spacer 102. By precisely aligning the needle module 101 with the spacer 102, the needle module 101 can be inserted into the spacer 102 by longitudinal movement, whereby the rectangular portion 109 passes through the inner retaining wall 110 of the spacer 102. Following longitudinal movement to insert the main housing portion 107 into the spacer 102, the needle module can be rotated (clockwise in this example) about its longitudinal axis relative to the spacer 102, causing the inner retaining wall 110 to engage with a corresponding cavity 111 in the main housing portion 107, locking the needle module 101 longitudinally with the spacer 102. Note that the needle module 101 can also be configured to couple via counterclockwise rotation. Such a coupling is often referred to as a bayonet coupling. A small protrusion 112 is disposed on the housing of the needle module 101 and cooperates with a circumferential recess 113 disposed on the inner peripheral wall of the spacer 102 near the distal end of the spacer. When the needle module 101 is inserted into the spacer, an edge 115 on the side of the distal housing portion 104 opposite the tip is positioned to abut a corresponding edge 116 on the distal end of the spacer 102, thereby inserting the small protrusion 112 into the recess 113. By rotating the needle module 101 as described above, the protrusions are locked into place by the snap fit connection formed at the first end 114 of the recesses 113, thereby providing a simple and reliable connection between the spacer 102 and the needle module 101.After use, the snap-fit ​​connection can be opened by applying a torque to the needle module 101 in the opposite direction (counterclockwise), after which the needle module 101 can be released from the spacer 102 by rotating it (counterclockwise) and withdrawing the needle module 101.

[0074] The same embodiment of device 100 is shown in FIG. 6 , with needle module 101 and spacer 102 shown in an exploded view. In the assembled state of needle module 101, distal housing portion 104 and main housing portion 107 contain a needle unit 120 with one or more needles 121 and a resilient element 122. Needle unit 120 is movable relative to the needle module housing. The resilient element is arranged as a biasing means for retaining needle distal end 123, i.e., the tip portion of the needle including the sharp point, within the housing when no force in direction I is applied to needle unit 120 to push needle distal end 123 through opening 105. Needle unit 120 further comprises an outwardly extending protrusion 124 arranged to be positioned in a corresponding groove 125 in main housing portion 107. Thus, needle unit 120 is movable relative to the housing in direction I, which is the longitudinal direction of device 100.

[0075] 7a shows in cross section the attachment procedure when the needle module 101, and more particularly the main housing part 107, is inserted into the spacer 102. The spacer 102 is then connected to a drive device 103 comprising a drive rod 130 for driving the proximal end 127 of the needle unit 120. A reservoir 128 for colorant is provided near the tip 106 of the distal housing part 104.

[0076] FIG. 7b again shows the device 100 with the needle module 101 mated with the spacer 102. During the attachment process, the drive rod 130 contacts the proximal end 127 of the needle unit 120, and as the needle module 101 is further pressed into the spacer 102, the needle unit 120 is moved longitudinally within the housing toward the tip 106 of the distal housing section 104, toward an intermediate position. This deforms the elastic element 122, generating an elastic force in the direction of the drive device 103. Due to this prestressing effect, the proximal end 127 of the needle unit 120 is biased to maintain contact with the distal end 131 of the drive rod 130. During this process, the needle distal end 123 punctures and penetrates the reservoir 128, allowing colorant, e.g., ink, to flow over the surface of the needle 121. The device 100 is now ready for reciprocating movement.

[0077] When the device 100 is actuated, the needle 121 reciprocates from the position shown in FIG. 7b to the position shown in FIGS. 8a and 8b, where the needle distal end 123 is in the extended position. The cross-section shown in FIG. 8b is rotated 90 degrees about the longitudinal axis 140 of the device 100, thereby also illustrating that the spacer 102 and the needle module 101 are not perfectly axisymmetric. In the extended position, the needle distal end 123 extends a certain maximum distance d3 from the hole 105 located at the tip 106 of the distal housing portion 104. This allows the needle 121 to penetrate the skin only to a depth equal to or less than the maximum distance d3. Therefore, colorant that can flow from the reservoir 128 along the needle 121 is inserted into the skin to a depth equal to or less than the maximum distance d3. This allows the depth of colorant insertion to be adjusted, ensuring that ink is deposited only in the top layer of the skin, creating a temporary mark on the skin.

[0078] It should be noted that, after the needle module 101 has been pre-mounted in a predetermined manner, if a force sufficient to overcome the elastic force of the elastic element 122 is applied to the needle unit 120 in direction I to push the needle distal end 123 through the opening 105, the front side 126 of the outwardly extending protrusion 124 will abut the inner side of the inner retaining wall 110 of the spacer 102, thereby limiting the displacement of the needle unit 120 and, therefore, the needle distal end 123. Thus, the maximum distance d3 that the needle 121 can extend from the housing distal end 104 is determined by cooperation between the front side 126 of the outwardly extending protrusion 124 and the surface of the inner retaining wall 110, as is evident in FIG. 8b. In general, by arranging limiting features as cooperating stop surfaces on the needle module 101 and the spacer 102, the maximum distance d3 can be easily determined from a limited number of dimensional parameters of the device 100. d3=d6-d5-d4 d6 represents the distance from the front face 126 of the outwardly extending projection 124 to the needle distal end 123, thereby representing the effective length of the needle unit 120, d5 is the length of the distal housing portion 104, and d4 is the width (or thickness) of the inner retaining wall 110. In a standardized needle module 101, the lengths d6 and d5 are given, so that the maximum distance d3, representing the maximum skin penetration depth, can be easily and reliably varied by changing the dimensions of the inner retaining wall 110 of the spacer.

[0079] The elastic element 122 of the device 100 is made from a sheet of rubber-like material so as to act as a tension spring, as clearly shown in Figures 7a to 8b. Obviously, other types of elastic elements can also be applied, for example compression springs made from a suitable elastic material, for example steel, as also shown in Figures 2, 3 and 9a to 9c.

[0080] 9a-9c show the spacer in more detail. Although the side 150 for connecting the spacer 102 to the drive device 103 can be any suitable connection means, for example, a similar bayonet connection. The connection mechanism near the distal end 151 of the spacer 102 is shown in more detail. In this embodiment, the spacer 102 includes inner retaining walls on either side of the spacer 102. Also clearly shown is the recess 113 for receiving a corresponding small protrusion 112 on the distal housing part 104. At a first end 114 of the recess 113, it can be seen that the recess is provided with a small upright feature 152, followed by a void 153 disposed adjacent to the upright feature 152. When the needle module 101 is inserted into the spacer 102, the small protrusion 112 on the distal housing part 104 is received by the recess 113. The needle module 101 is then rotated about its axis, after which the small protrusion 112 contacts the upright feature 152. By applying sufficient torque, the spacer 102 and / or distal housing portion 104 may deform slightly, allowing the small protrusions 112 to pass through the upright features 152 and fit into the voids 153 arranged to receive the small protrusions 152.

[0081] 10a to 10c show more schematically an alternative embodiment of the device 200. The device 200 comprises a needle module 201, a spacer 202, and a drive device 203, which are interconnected by a bayonet connection, a snap-fit ​​connection, a screw connection, or any other suitable connection as described in detail in the previous embodiments. The needle module 201 comprises a housing 204, which may comprise multiple housing parts, and a needle unit 220, which is substantially enclosed by the housing in a retracted state and comprises at least a needle 221. The needle unit 220 is movable relative to the housing 204 in a direction I, which is parallel to a longitudinal axis 240 of the device 200. A biasing means is an elastic element 222, such as a spring or any other suitable element, which is provided to bias the needle unit 220 to a retracted position or an intermediate position in which the needle distal end 223 is maintained within the housing 204. An outwardly extending protrusion 224, which is part of a restricting mechanism as will be explained below, is again provided near the proximal end 227 of the needle unit 220.

[0082] The spacer 202 is also arranged to be coupled to the needle unit 201 at its distal end 251 and to the drive device 203 at its proximal end 252. A blocking surface at the proximal end of the inner retaining wall 210 disposed on the inner circumferential wall of the spacer cooperates with a corresponding blocking surface disposed on the housing coupling protrusion 219 of the needle module 201 to couple the needle module 201 to the spacer 202.

[0083] The illustrated embodiment of the drive device 203 includes a decoupling mechanism 260 for at least partially decoupling the movement of the drive rod 230 that drives the proximal end 227 of the needle unit 220, and a motor 261 that generates reciprocating motion. The motor 261 is attached to a transmission module 262 that includes a swash plate 271 or any other suitable mechanism that converts rotational motion into reciprocating translational motion, in order to convert the output of the motor 261 into a suitable reciprocating motion for driving the needle unit 220. The decoupling mechanism 260 further includes a slide member 263 that is movable in direction I relative to the drive rod 230, and a guide member 264 that is fixed to a housing 265 of the drive device 203.

[0084] A first coupling spring 266, or any other suitable biasing means, biases the drive rod 230 and the slide member 263 in opposite directions relative to each other. For this purpose, the first coupling spring 266 is provided between the drive rod mounting location 268 and the slide member mounting location 270. The first coupling spring 266 is preferably prestressed by imposing an initial deformation. To ensure that the separation mechanism 260 is maintained, the drive rod is provided with a fixing means, such as an abutment shoulder 269, which locks behind the slide member mounting location 270 and ensures the integrity of the separation mechanism 260.

[0085] A second coupling spring 267, or any other suitable biasing means, is provided between the drive rod mounting position 268 and the guide member distal end 272, and biases the drive rod 230 toward the motor 261. Thus, the second coupling spring 267 presses the slide member contact end 273 against the swash plate 271 via the drive rod 230, the first coupling spring 266, and the slide member 263. This ensures that the slide member 263 follows the movement of the swash plate 271, as can also be seen in Figures 10b and 10c. This results in the desired reciprocating motion of the slide member 263 being imparted to the movable needle unit 220 via the separation mechanism 260.

[0086] 10b and 10c, the needle 221 has reached its maximum extension distance d3, at which point the outwardly extending protrusion 224, which is part of the limiting mechanism, contacts the inner retaining wall 210 of the spacer, as shown in detail in FIG. 11. Thus, the means for limiting the maximum extension distance d3 (i.e., the limiting mechanism) is formed by mutual cooperation between the spacer 202 and the housing 204 of the needle module 201. In the illustrated embodiment, the inner retaining wall 210 is a stepped protrusion comprising a first step 281 and a second step 282. The surface of the outwardly extending protrusion 224 abuts against the surface of the first step 281 of the inner retaining wall 210, thereby blocking the needle unit from moving in direction I toward the opening 205 located at the distal end of the device 100. The needle unit 201 is coupled via the spacer 202 by locking the housing coupling protrusion 219 with the second step 282 of the inner retaining wall 210. It should be noted that in this coupled state, the outwardly extending protrusion 224 cannot abut the second step 282 or the housing coupling projection 219 .

[0087] The operating principle of the separation mechanism is further clarified by Figures 10b and 10c. In Figure 10a, the needle is in an intermediate position, with the needle distal end 223 extending into the housing. Figures 10b and 10c show the needle distal end 223 at its maximum extension position d3, except that in Figure 10b, the drive unit, in this case the swash plate 271, has not yet reached its maximum displacement. In Figure 10b, it can be seen that the abutment shoulder 269 of the drive rod 230 is still in contact with the slide member mounting location 270, preferably by the pre-tensioned first coupling spring 266. At this point, as previously explained, the needle unit 220 is blocked by the limiting means, whereby the drive rod 230, whose distal end 231 is in direct contact with the proximal end 227 of the needle unit 220, is also blocked from further movement in direction I toward the distal end of the device. Thus, as swash plate 271 moves toward its maximum displacement, it also presses sliding member 263 to its maximum displacement, causing relative displacement between drive rod 230 and sliding member 263. This relative displacement deforms first coupling spring 266, thereby exerting a counter force on sliding member 263, urging it toward proximal end 241 of the device, and on drive rod 230, urging it toward needle unit 220. Once swash plate 271 moves from its maximum displacement, first coupling spring 266 is again allowed to expand, thereby biasing sliding member 263 and forcing sliding member contact end 273 to maintain contact with swash plate 271, thereby following the movement of swash plate 271. At some point during the return movement of the sliding member 263, the abutment shoulder 269 again contacts the sliding member mounting location, causing the drive rod 230 and sliding member 263 to move together, after which the needle unit 220 is urged towards the retracted position by the elastic element 222. The needle distal end 223 therefore moves with the needle unit 220, thereby again retracting into the housing 204. The motor 261 is arranged to be driven continuously, whether for a long or short period of time, thereby resulting in reciprocating movement of the needle distal end 223.

[0088] Clearly, the decoupling mechanism 260 ensures that the maximum extension distance d3 of the needle distal end 223 can be accurately set and maintained. Without this decoupling mechanism 260, excessive strokes of the actuation device 203 would have to be absorbed by elastic or plastic deformation of various parts of the device 200, which would result in excessive forces being applied to various parts of the system, potentially causing damage and impairing functionality and precision.

[0089] It should be noted that it is possible to combine all the different embodiments of the needle unit 1, 101, 201, the spacer 3, 102, 202 and the drive device 103, 203. Furthermore, the invention is not limited to the embodiments shown, but extends to other embodiments that fall within the scope of the appended claims.

Claims

1. 1. A needle module for use in a reciprocating skin perforation device, for introducing ink only into the epidermis of a patient's skin to prevent a skin mark from becoming a permanent mark, the needle module comprising: a needle unit that pierces the patient's skin to introduce ink; a housing; and a biasing mechanism, wherein the needle unit has a needle and is movable relative to the housing between an extended position in which a distal end of the needle extends from the distal end of the housing and a retracted position in which the distal end of the needle is disposed within the housing, the biasing mechanism being arranged to bias the needle unit towards the retracted position, the needle module further comprising a limiting mechanism; the limiting mechanism is arranged to limit relative movement of the needle unit outward from the distal end of the housing to a maximum extension distance during movement toward the extended position, the maximum extension distance being 1.5 mm or less, a distance at which ink is introduced only into the epidermis of the patient's skin; In the retracted position, a proximal end of the needle unit extends into the housing; A needle module for use in a reciprocating skin puncture device, characterized in that the limiting mechanism is further arranged to limit displacement of the proximal end of the needle in the retracted position, and the proximal end of the needle is retained within the housing.

2. The needle module of claim 1 , wherein the limiting mechanism comprises cooperating stop surfaces for limiting the relative movement between the needle unit and the housing.

3. The needle module of claim 1 or 2, wherein the biasing mechanism is further arranged to retain a proximal end of the needle within the housing.

4. The needle module of claim 1 , wherein the housing includes a reservoir containing a colorant, the colorant being an ink, for introduction into the skin.

5. A reciprocating skin puncture device comprising: the needle module according to any one of claims 1 to 4; and a drive device, the drive device comprising a motor that reciprocates a drive rod that reciprocates the needle unit.

6. 6. The device of claim 5, further comprising a separation mechanism for reciprocatingly driving the needle unit between the retracted position and the extended position, the separation mechanism having a first end arranged to be reciprocated and a second end arranged to drive the needle unit, the first end and the second end being movable relative to one another, the first end being reciprocally movable with a first displacement amplitude and the second end being movable with a second displacement amplitude that is smaller than the first displacement amplitude.

7. 7. The device of claim 5 or 6, wherein the needle module is arranged such that upon attachment of the needle module to the drive device, the distal end of the needle moves to an intermediate position, the intermediate position being between the extended position and the retracted position.

8. 8. The device of claim 5, wherein the motor is coupled to the needle unit via the separation mechanism disposed between the motor and the drive rod, and the second end receives the drive rod.

9. 9. The device of claim 5, further comprising a spacer for setting the extended position of the needle unit, the spacer being arranged for positioning between a drive device and the needle module to adjust the relative position of the housing and a drive rod of the drive device.

10. 10. A device according to any one of claims 5 to 9, wherein the device is arranged so that the needle module, spacer and / or drive device can be interconnected by a bayonet connection.

11. 11. A device according to any one of claims 5 to 10, comprising non-magnetic components, the needle being made from a non-magnetic material being titanium or aluminium.

12. The device of claim 11 , wherein the motor comprises a pneumatic motor.

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