Multi-filament printing system

Abstract

Multi-filament printing system (1), comprising a drive motor (18) with a drive shaft (2), characterized in that the multi-filament printing system (1) further comprises at least one servo motor (8) with an adjusting shaft (3), a first eccentric gear (31) and a second eccentric gear (32), which are arranged out of phase with one another and eccentrically on the adjusting shaft (3), and at least one first feed gear (21) and one second feed gear (22), each of which is arranged centrally on the adjusting shaft (3), wherein, depending on a position of the adjusting shaft (3), only the first eccentric gear (31) or the second eccentric gear (32) is in engagement with the drive shaft (2), so that a drive movement of the drive shaft (2) can be transmitted to the first eccentric gear (31) or the second eccentric gear (32), wherein the first eccentric gear (31) is connected to the first feed gear (21) in a rotationally fixed manner, wherein the second eccentric gear (32) is connected to the second feed gear (22) in a rotationally fixed manner, so that the drive movement can be further transmitted to the first feed gear (21) or the second feed gear (22), wherein the first feed gear (21) is designed to convey a first printing filament to a filament outlet nozzle (5), wherein the second feed gear (22) is designed to convey a second printing filament to the filament outlet nozzle (5), so that the drive movement can be transferred to a first printing filament or a second printing filament, so that the first printing filament or the second printing filament can be selectively fed to the filament outlet nozzle (5).

Description

BACKGROUND OF THE INVENTION

[0001] The main problem with existing direct extruders is the need to change filaments to print different colors or materials. This leads to interruptions and increases the complexity and error-proneness of the printing process.

[0002] Color 3D prints often appear rough or washed out because they are always a difficult compromise between printing speed, color fidelity, and resolution.

[0003] When using existing technology, this is based, among other things, on the fact that filament wires of different primary colors must be melted and applied to the printed object simultaneously or in short sequences one after the other. STATE OF THE ART

[0004] Three basic technologies are used for this purpose: 1. The use of multiple print heads and the controlled, sequential printing of filament material of different colors.

[0005] Due to the inevitable spatial offset of the print heads / extruders, a differentiated ink application is problematic.

[0006] 2. The controlled sequential feeding and melting of differently colored filaments with one print head.

[0007] The disadvantage here is that residues of previous color filaments often make the color application appear unclean.

[0008] In addition, more frequent jams in the filament feed often cause color errors and increased service costs.

[0009] 3. Coloring by inkjet printing after “melting” a transparent or a base-colored filament.

[0010] Applying inks to melt-in filaments is less durable and also less visually consistent than using dyed material. TASK

[0011] The object of the present invention is therefore to combine the contradictory requirements without causing further problems and disadvantages. SOLUTION

[0012] This object is achieved by the inventive multi-filament printing system according to claim 1.

[0013] The invention relates to a multi-filament printing system comprising a drive motor with a drive shaft.

[0014] The multi-filament printing system according to the invention is characterized in that the multi-filament printing system further comprises at least one servo motor with an adjusting shaft, a first eccentric gear and a second eccentric gear, which are arranged eccentrically on the adjusting shaft and out of phase with one another, and at least one first feed gear and a second feed gear, which are each arranged centrally on the adjusting shaft, wherein, depending on a position of the adjusting shaft, exclusively the first eccentric gear or the second eccentric gear is in engagement with the drive gear, so that a drive movement of the drive shaft can be transmitted to the first eccentric gear or the second eccentric gear, wherein the first eccentric gear is connected in a rotationally fixed manner to the first feed gear, wherein the second eccentric gear is connected in a rotationally fixed manner to the second feed gear,so that the drive movement can be further transmitted to the first feed gear or the second feed gear, wherein the first feed gear is designed to feed a first printing filament into the filament outlet nozzle, wherein the second feed gear is designed to feed a second printing filament into the filament outlet nozzle, so that the drive movement can be transmitted to a first printing filament or a second printing filament, so that the first printing filament or the second printing filament can be selectively fed to the filament outlet nozzle.

[0015] This results in the advantage over the known multi-filament printing systems that only a single drive motor is used to selectively feed the at least two printing filaments into the filament outlet nozzle.

[0016] Since only one eccentric gear is selectively engaged with the drive shaft at a time, by selecting a corresponding eccentric gear, for example the first or the second eccentric gear, a feed gear that is non-rotatably connected to the eccentric gear, i.e. the first feed gear or the second feed gear, can be driven, which in turn feeds the corresponding printing filament, namely the first printing filament or the second printing filament, into the filament outlet nozzle, so that this printing filament is used for the printing process.

[0017] The drive shaft is advantageously designed as a drive wheel, i.e. the drive shaft and the drive wheel are a one-piece component.

[0018] The adjusting shaft is advantageously designed as a polygonal shaft with a polygonal cross-sectional profile. For example, the adjusting shaft can be designed as a triangular shaft, a square shaft, a pentagonal shaft, or a hexagonal shaft. Multi-edged shafts are also conceivable and preferred.

[0019] The multi-filament printing system advantageously includes any number of eccentric gears and feed gears, allowing a variety of printing filaments to be selectively fed into the filament outlet nozzle. However, regardless of the specific number of eccentric gears or feed gears, or the printing filaments to be fed, only a single drive motor is required.

[0020] This makes it easy to create multi-colored 3D models, for example.

[0021] Especially at high printing speeds, the invention enables almost inertia-free control of the printing filament feed.

[0022] According to a preferred embodiment of the invention, it is provided that the first feed gear is designed to press its toothing into the first printing filament in order to transmit the drive movement and that the second feed gear is designed to press its toothing into the second printing filament in order to transmit the drive movement.

[0023] This means that the advance or retraction of the printing filaments occurs when the first feed gear and the second feed gear press their teeth into the respective printing filament, thus transmitting the drive movement in the corresponding direction. This enables virtually slip-free advance or retraction.

[0024] According to a further preferred embodiment of the invention, it is provided that the first feed gear and the second feed gear are rotatably mounted on the adjusting shaft.

[0025] This allows the feed gears to rotate freely on the adjustment shaft on which they are mounted. The rotational movement of the feed gears is thus advantageously independent of the rotational movement of the adjustment shaft, allowing the adjustment shaft to assume the required position to engage the desired eccentric gear with the drive gear without affecting the advance or retraction of a printing filament.

[0026] According to a further preferred embodiment of the invention, it is provided that the first eccentric gear is rotatably mounted on the adjusting shaft via a first eccentric disc and the second eccentric gear is rotatably mounted on the adjusting shaft via a second eccentric disc.

[0027] The first eccentric disc and the second eccentric disc are each arranged eccentrically on the adjusting shaft, but the first eccentric gear and the second eccentric gear are mounted centrally on the corresponding eccentric disc.

[0028] Advantageously, the first eccentric disc and the second eccentric disc are mounted on the adjusting shaft in a rotationally fixed manner. However, the first eccentric gear and the second eccentric wheel are rotatably mounted on the first eccentric disc and the second eccentric disc, respectively. Thus, by changing the position of the adjusting shaft, i.e., by rotating the adjusting shaft, the center of rotation of the first eccentric wheel and the second eccentric wheel can be adjusted. Depending on the position of the adjusting shaft, one eccentric wheel can be brought into engagement with the drive wheel.

[0029] According to a preferred embodiment of the invention, it is provided that the first eccentric gear and the second eccentric gear are arranged on the adjusting shaft in a phase-shifted manner relative to one another.

[0030] The phase offset ensures that only one eccentric wheel engages with the drive wheel at a specific position of the adjustment shaft.

[0031] For example, with two eccentric wheels the phase offset can be 180°, with three eccentric wheels it can be 120° and with four eccentric wheels it can be 90°.

[0032] According to a preferred embodiment of the invention, it is provided that the first feed gear has three first mandrels and the second feed gear has three second mandrels, wherein the first eccentric gear has three first bores and the second eccentric gear has three second bores, wherein each of the three first mandrels engages in one of the three first bores, wherein each of the three second mandrels engages in one of the three second bores, wherein the first mandrels and bores are designed such that each first mandrel runs along an inner circumference of a first bore during a rotational movement of the first eccentric gear, and wherein the second mandrels and bores are designed such that each second mandrel runs along an inner circumference of a second bore during a rotational movement of the second eccentric gear.

[0033] This represents a mechanically robust and reliable way to non-rotatably couple a feed gear mounted centrally on the adjustment shaft with an eccentric gear mounted eccentrically on the adjustment shaft. Thus, the corresponding feed gear can follow the rotational movement of the corresponding eccentric gear, even though it has a different center of rotation.

[0034] According to a preferred embodiment of the invention, it is provided that the three first mandrels and the three first bores are each arranged on an identical diameter at an angular distance of 120 °, so that the first feed gear can be driven without play by the first eccentric gear and that the three second mandrels and the three second bores are each arranged on an identical diameter at an angular distance of 120 °, so that the second feed gear can be driven without play by the second eccentric gear.

[0035] By enabling a largely backlash-free rotary connection between the respective feed gear and the respective eccentric gear, a correspondingly precise drive of the feed wheels is also possible, which in turn enables precise advancement and retraction of the printing filaments. This enables high-quality printed products.

[0036] According to a preferred embodiment of the invention, it is provided that the multi-filament printing system has at least a first filament channel and a second filament channel for guiding a respective printing filament, wherein the first filament channel has a first filament inlet for receiving a first printing filament, wherein the second filament channel has a second filament inlet for receiving a second printing filament, and wherein the first filament channel and the second filament channel are combined to form a common filament outlet nozzle.

[0037] The filament channels are designed in such a way that they each have their own filament inlet for receiving or feeding a printing filament via a corresponding feed gear. Along the filament channels, the filament channels then converge, i.e., they combine to form a single filament channel, which then leads to the filament outlet nozzle.

[0038] This results in the advantage that the filament required for 3D printing is always supplied at the same location on the extruder, namely at the single filament outlet nozzle. This simplifies the printing process and improves the quality of the printed products.

[0039] According to a preferred embodiment of the invention, it is provided that the drive movement can be carried out as a forward movement and as a backward movement.

[0040] This allows the printing filaments to be advanced to the filament exit nozzle in a single feed motion, enabling the printing process with that filament. If the printing process is to be continued with a different filament, the drive movement can be performed as a reverse motion to retract the printing filament far enough within the filament channel that the filament channel in front of the filament exit nozzle is clear, allowing another printing filament to be advanced to the filament exit nozzle in a single feed motion.

[0041] According to a preferred embodiment of the invention, the multi-filament printing system comprises four eccentric gears and four feed gears, wherein the four eccentric gears are each arranged eccentrically on the adjustment shaft and are phase-offset from one another, and wherein the four feed gears are each arranged centrally on the adjustment shaft, wherein, depending on a position of the adjustment shaft, only one eccentric gear is in engagement with the drive shaft, so that a drive movement of the drive shaft can be transmitted to one of the eccentric gears, wherein each eccentric gear is connected in a rotationally fixed manner to a feed gear, so that the drive movement can be further transmitted to one of the feed gears, wherein each of the feed gears is designed to feed a respective printing filament into the filament outlet nozzle, so that the drive movement can be transmitted to one of the printing filaments,so that the printing filaments can be selectively fed to the filament outlet nozzle.

[0042] The design with four eccentric gears, four feed gears, and four printing filaments has proven particularly suitable in practice. It represents an excellent compromise between flexibility and mechanical complexity and manufacturing costs. MORE DETAILS FROM THE DRAWINGS

[0043] It shows Fig. 1 shows, by way of example and schematically, a side view of an exemplary embodiment of a multi-filament printing system according to the invention, Fig. 2 the multi-filament printing system of the Fig. 1 in another view, Fig. 3 the multi-filament printing system of the Fig. 1 in a partially opened housing view, so that part of a feed mechanism of the multi-filament printing system can be seen, Fig. 4 another view of the feed mechanism of the multi-filament printing system of the Fig. 1., Fig. 5 a longitudinal section through the multi-filament printing system of the Fig. 1, Fig. 6 shows, by way of example and schematically in a side view, the first feed gear, the eccentric gear, the second feed gear, the second eccentric gear connected, the third feed gear, the third eccentric gear, the fourth feed gear and the fourth eccentric gear of the multi-filament printing system of Fig. 1, Fig. 7 shows an exemplary and schematic plan view of the first eccentric wheel of the multi-filament printing system of Fig. 1, Fig. 8 shows an exemplary and schematic side view of the adjustment shaft of the multi-filament printing system of Fig. 1 with the first eccentric disc, the second eccentric disc, the third eccentric disc and the fourth eccentric disc and Fig. 9 is an exemplary and schematic plan view of the adjusting shaft of the Fig. 8.

[0044] Identical objects, functional units, and comparable components are designated by the same reference symbols throughout the figures. These objects, functional units, and comparable components are identical in terms of their technical features, unless explicitly or implicitly stated otherwise in the description.

[0045] Fig. 1 shows, by way of example and schematically, a side view of an exemplary embodiment of a multi-filament printing system 1 according to the invention.

[0046] The multi-filament printing system 1 comprises a housing 9 in which a drive shaft 2 is arranged. The drive shaft 2 is designed, for example, as a drive gear 2, i.e., the drive shaft 2 and the drive gear 2 are a single, integral component. Additionally, an adjustment shaft 3 is arranged within the housing 9, on which, for example, eccentric gears 31, 32, 33, 34 and feed gears 21, 22, 23, 24 are rotatably mounted.

[0047] On a pressure lever shaft 4 there is a pressure lever 10 (not shown in Fig. 1) which exerts a contact pressure on the printing filaments so that they are applied to the feed gears 21, 22, 23, 24 with a predetermined pressure.

[0048] Also to be seen in Fig. 1 are a cooling device 6, consisting of cooling fins and a fan, as well as a heating element 7 for melting the printing filament.

[0049] The molten printing filament can then be dispensed via a filament outlet nozzle 5 to create a 3D printing model.

[0050] Fig. 2 shows the multi-filament printing system 1 of the Fig. 1 in another view.

[0051] In the presentation of the Fig. 2 above you can see the actuator 8, which is used to adjust the position of the adjusting shaft 3.

[0052] Depending on the position of the adjusting shaft 3, only the first eccentric gear 5 (not shown in Fig. 2), the second eccentric gear 6 (not shown in Fig. 2), the third eccentric gear 7 (not shown in Fig. 2) or the fourth eccentric gear 8 (not shown in Fig. 2) in engagement with the drive wheel 2.

[0053] Also visible are the first pressure lever 10, the second pressure lever 11, the third pressure lever 12 and the fourth pressure lever 13, each of which is not completely enclosed by the housing 9 but is accessible from outside the housing 9.

[0054] Also featured in Fig. 2 are a first filament inlet 14, a second filament inlet 15, a third filament inlet 16 and a fourth filament inlet 17, through which four independent printing filaments can be fed.

[0055] Fig. 3 shows the multi-filament printing system 1 of the Fig. 1 in a partially opened housing view, so that part of a feed mechanism of the multi-filament printing system 1 can be seen.

[0056] Shown here is first the drive motor 18, which is connected to the drive shaft 2.

[0057] A first printing filament (not shown in Fig. 3) can be conveyed to the filament outlet nozzle 5 via the first feed gear 21 in conjunction with one of the pressure rollers 19, in that the first feed gear 21 transmits its rotational movement to the first printing filament, so that the latter is pushed in the direction of the filament outlet nozzle 5. To this end, the first feed gear presses its teeth onto the first printing filament, resulting in almost slip-free propulsion. The contact pressure is provided by the first pressure roller 19, which is connected on the one hand to the first pressure lever 10 and on the other hand can be subjected to a specifically adjustable contact pressure by the first adjusting screw 20. For this purpose, the first adjusting screw 20 also comprises a mechanical spring element, which provides the contact pressure by setting a preload.

[0058] The first feed gear 21 is mounted on a bearing 42 rotatably mounted on the adjusting shaft.

[0059] In the lower part of the display of the Fig. 3 shows a housing part of the housing 9, which contains the heat sink 6 and the heating element 7 (not shown in Fig. 4). Also visible is the filament exit nozzle 5.

[0060] Fig. 4 shows another view of the feed mechanism of the multi-filament printing system 1 of the Fig. 1.

[0061] The adjusting shaft 3 can be seen, on which the four feed gears, namely the first feed gear 21, the second feed gear 22, the third feed gear 23 and the fourth feed gear 24, are rotatably mounted.

[0062] The four eccentric gears, namely the first eccentric gear 31, the second eccentric gear 32, the third eccentric gear 33 and the fourth eccentric gear 34, are also rotatably mounted on the adjusting shaft 3.

[0063] The first feed gear 21 is connected in a rotationally fixed manner to the first eccentric gear 31, the second feed gear 21 is connected in a rotationally fixed manner to the second eccentric gear 31, the third feed gear 21 is connected in a rotationally fixed manner to the third eccentric gear 31 and the fourth feed gear 21 is connected in a rotationally fixed manner to the fourth eccentric gear 31.

[0064] As can be seen, only the first eccentric gear 31 is in engagement with the drive gear 2, which is driven by the drive motor 18. Thus, a drive movement of the drive motor 18 can be transmitted via the drive shaft 2 or the drive gear 2 to the first eccentric gear 31 and from the first eccentric gear 31 to the first feed gear 21, which converts the drive movement of the drive motor 18 into a feed movement of the first printing filament (not shown in Fig. 4) is implemented.

[0065] The servomotor 8 can transmit a rotary motion to the adjusting shaft 3, causing it to assume a different position. Depending on the position of the adjusting shaft 3, only one of the four eccentric gears, namely the first eccentric gear 31, the second eccentric gear 32, the third eccentric gear 33, and the fourth eccentric gear 34, can be brought into engagement with the drive gear 2.

[0066] In the lower part of the display of the Fig. 4 shows a housing part of the housing 9, which contains the heat sink 8 (not shown in Fig. 4) and the heating element 7 (not shown in Fig. 4). Also visible is the filament exit nozzle 5.

[0067] Fig. 5 shows a longitudinal section through the multi-filament printing system of the Fig. 1.

[0068] Four filament channels can be seen, namely a first filament channel 26, a second filament channel 27, a third filament channel 28 and a fourth filament channel 29.

[0069] The first filament channel 26 has a first filament inlet 14, the second filament channel 27 has a second filament inlet 15, the third filament channel 28 has a third filament inlet 16, the fourth filament channel 29 has a fourth filament inlet 17.

[0070] The filament channels 26, 27, 28, 29 converge in a filament channel junction 30 and continue into a common area that runs through the heat sink 6, the heating element 7 and finally the filament outlet nozzle 5.

[0071] This means that one of the four available printing filaments (not shown in Fig. 5) are conveyed by one of the four feed gears 21, 22, 23, 24 through the corresponding filament channel 26, 27, 28, 29 and the filament channel junction 30 to the filament outlet nozzle 5.

[0072] When a desired change of the printing filament is required, for example when changing from the first printing filament to the third printing filament, the first eccentric gear 31 is initially in contact with the drive gear 2 (not shown in Fig. 5) and transmits a drive movement of the drive motor 18 (not shown in Fig. 5) in the sense of a forward movement via the first feed gear 21 onto the first printing filament.

[0073] To clear the filament channel junction 30, the area of ​​the heat sink 7, the heating element 7, and the filament outlet nozzle 5 for the third printing filament, the drive motor 18 reverses its direction of rotation so that the drive movement is now executed as a reverse movement and transmitted by the first feed gear 21 to the first printing filament. The first printing filament is thereby retracted into the area of ​​the first filament channel 26.

[0074] The servo motor 8 then changes the position of the adjusting shaft 3 so that the first eccentric gear 31 is disengaged from the drive gear 2 and instead the third eccentric gear 33 engages with the drive gear 2.

[0075] The drive motor 18 now changes its drive direction again, so that the drive movement is again executed as a forward movement. This conveys the third printing filament from the area of ​​the third filament channel into the filament channel junction 30, the area of ​​the heat sink 7, the area of ​​the heating element 7, and finally to the filament outlet nozzle 5.

[0076] Fig. 6 shows, by way of example and schematically in a side view, the first feed gear 21, the eccentric gear 31, the second feed gear 22, the second eccentric gear 32 connected, the third feed gear 23, the third eccentric gear 33, the fourth feed gear 24 and the fourth eccentric gear 34 of the multi-filament printing system of the Fig. 1.

[0077] The first feed gear 21 is connected in a rotationally fixed manner to the first eccentric gear 31, the second feed gear 22 is connected in a rotationally fixed manner to the second eccentric gear 32, the third feed gear 23 is connected in a rotationally fixed manner to the third eccentric gear 33 and the fourth feed gear 24 is connected in a rotationally fixed manner to the fourth eccentric gear 34.

[0078] Also visible are the adjusting shaft 3, on which the feed gears 21, 22, 23, 24 and the eccentric gears 31, 32, 33, 34 are rotatably mounted, as well as the drive gear 2, which engages with one of the eccentric gears 31, 32, 33, 34.

[0079] Fig. Figure 7 shows an exemplary and schematic plan view of the first eccentric wheel 31 of the multi-filament printing system of Fig. 1.

[0080] The first eccentric gear 31 with three first bores 36 can be seen. The three first mandrels 35, which are arranged in a rotationally fixed manner on the first feed gear 21, engage in the three first bores.

[0081] During a rotational movement or a drive movement of the first eccentric gear 31, the three first mandrels 35 each run along an inner circumference of a first bore 36. This ensures a torsion-resistant connection of the first eccentric gear 31 to the first feed gear 21, although the first eccentric gear 31 - in contrast to the first feed gear 21 - is not mounted centrally on the adjusting shaft 3.

[0082] The first eccentric gear 31 is mounted eccentrically on the adjusting shaft 3 via the first eccentric disc 38. To reduce friction losses, the first eccentric gear 31 is also mounted on the first eccentric disc 38 via a bearing 27.

[0083] As can be seen, the four eccentric wheels 31, 32, 33, 34 have a phase offset of, for example, 70° with regard to the eccentricity of their bearing on the adjusting shaft 3, so that only one of them can be in engagement with the drive gear 2 at a time.

[0084] Fig. 8 shows an exemplary and schematic side view of the adjustment shaft 3 of the multi-filament printing system 1 of Fig. 1 with the first eccentric disc 38, the second eccentric disc 39, the third eccentric disc 40 and the fourth eccentric disc 41.

[0085] The phase offset of the four eccentric discs 38, 39, 40, 41 can be clearly seen, which ensures the already described phase offset of the eccentric wheels 31, 32, 33, 34 arranged on them.

[0086] Fig. 9 shows an exemplary and schematic plan view of the adjusting shaft 3 of the Fig. 8.

[0087] Here, too, the phase shift of the four eccentric discs 38, 39, 40, 41 can be seen, which subsequently ensures the phase shift of the eccentric wheels 31, 32, 33, 34 arranged on them. Reference symbol 1 multi-filament printing system 2 drive shaft, drive gear 3 Adjustment shaft 4 Pressure lever shaft 5 Filament exit nozzle 6 heat sinks 7 Heating element 8 Actuator 9 housings 10 first pressure lever 11 second pressure lever 12 third pressure lever 13 fourth pressure lever 14 first filament inlet 15 second filament input 16 third filament input 17 fourth filament input 18 Drive motor 19 first pressure roller 20 first adjustment screw 21 first feed gear 22 second feed gear 23 third feed gear 24 fourth feed gear 25 Housing part for heat sink and filament outlet nozzle 26 first filament canal 27 second filament channel 28 third filament canal 29 fourth filament canal 30 Filament channel merging 31 first eccentric gear 32 second eccentric gear 33 third eccentric gear 34 fourth eccentric gear 35 first thorn 36 first drilling 37 Bearing of the first eccentric gear 38 first eccentric disc 39 second eccentric disc 40 third eccentric disc 41 fourth eccentric disc 42 Bearing of the first feed gear

Claims

[1] Multi-filament printing system (1), comprising a drive motor (18) with a drive shaft (2), characterized by that the multi-filament printing system (1) further comprises at least one servo motor (8) with an adjusting shaft (3), a first eccentric gear (31) and a second eccentric gear (32), which are arranged out of phase with each other and eccentrically on the adjusting shaft (3), and at least one first feed gear (21) and one second feed gear (22), each of which is arranged centrally on the adjusting shaft (3), wherein, depending on a position of the adjusting shaft (3), only the first eccentric gear (31) or the second eccentric gear (32) is in engagement with the drive shaft (2), so that a drive movement of the drive shaft (2) can be transmitted to the first eccentric gear (31) or the second eccentric gear (32), wherein the first eccentric gear (31) is connected to the first feed gear (21) in a rotationally fixed manner, wherein the second eccentric gear (32) is connected to the second feed gear (22) in a rotationally fixed manner, so that the drive movement can be further transmitted to the first feed gear (21) or the second feed gear (22), wherein the first feed gear (21) is designed to convey a first printing filament to a filament outlet nozzle (5), wherein the second feed gear (22) is designed to convey a second printing filament to the filament outlet nozzle (5), so that the drive movement can be transferred to a first printing filament or a second printing filament, so that the first printing filament or the second printing filament can be selectively fed to the filament outlet nozzle (5). [2] Multi-filament printing system (1) according to claim 1, characterized bythat the first feed gear (21) is designed to press its toothing into the first printing filament in order to transmit the drive movement and that the second feed gear (22) is designed to press its toothing into the second printing filament in order to transmit the drive movement. [3] Multi-filament printing system (1) according to at least one of claims 1 and 2, characterized by that the first feed gear (21) and the second feed gear (22) are rotatably mounted on the adjusting shaft (3). [4] Multi-filament printing system (1) according to at least one of claims 1 to 3, characterized by that the first eccentric gear (31) is rotatably mounted on the adjusting shaft (3) via a first eccentric disc (38) and the second eccentric gear (32) is rotatably mounted on the adjusting shaft (3) via a second eccentric disc (39). [5] Multi-filament printing system (1) according to at least one of claims 1 to 4, characterized bythat the first eccentric gear (31) and the second eccentric gear (32) are arranged on the adjusting shaft (3) in phase with one another. [6] Multi-filament printing system (1) according to at least one of claims 1 to 5, characterized by that the first feed gear (21) has three first mandrels (35) and the second feed gear (22) has three second mandrels, wherein the first eccentric gear (31) has three first bores (36) and the second eccentric gear (32) has three second bores, wherein each of the three first mandrels (35) engages in one of the three first bores (36), wherein each of the three second mandrels engages in one of the three second holes, wherein the first mandrels (35) and bores (36) are designed such that each first mandrel (35) runs along an inner circumference of a first bore (36) during a rotational movement of the first eccentric gear (31) and wherein the second mandrels and bores are designed such that each second mandrel runs along an inner circumference of a second bore during a rotational movement of the second eccentric gear (32). [7] Multi-filament printing system (1) according to at least one of claims 1 to 6, characterized by that the three first mandrels (35) and the three first bores (36) are each arranged on an identical diameter at an angular distance of 120°, so that the first feed gear (21) can be driven without play by the first eccentric gear (31) and that the three second mandrels and the three second bores are each arranged on an identical diameter at an angular distance of 120°, so that the second feed gear (22) can be driven without play by the second eccentric gear (32). [8] Multi-filament printing system (1) according to at least one of claims 1 to 7, characterized bythat the multi-filament printing system (1) has at least a first filament channel (26) and a second filament channel (27) for guiding a respective printing filament, wherein the first filament channel (26) has a first filament inlet (14) for receiving a first printing filament, wherein the second filament channel (27) has a second filament inlet (15) for receiving a second printing filament, and wherein the first filament channel (26) and the second filament channel (27) are combined to form a common filament outlet nozzle (5). [9] Multi-filament printing system (1) according to at least one of claims 1 to 8, characterized by that the drive movement can be carried out as a forward movement and as a backward movement. [10] Multi-filament printing system (1) according to at least one of claims 1 to 9, characterized bythat the multi-filament printing system (1) has four eccentric gears (31, 32, 33, 34) and four feed gears (21, 22, 23, 24), wherein the four eccentric gears (31, 32, 33, 34) are each arranged out of phase with one another and eccentrically on the adjusting shaft (3) and wherein the four feed gears (21, 22, 23, 24) are each arranged centrally on the adjusting shaft (3), wherein, depending on a position of the adjusting shaft (3), only one of the eccentric gears (31, 32, 33, 34) is in engagement with the drive shaft (2), so that a drive movement of the drive shaft (2) can be transmitted to one of the eccentric gears (31, 32, 33, 34), wherein each eccentric gear (31, 32, 33, 34) is connected in a rotationally fixed manner to each feed gear (21, 22, 23, 24), so that the drive movement can be further transmitted to one of the feed gears (21, 22, 23, 24), wherein each of the feed gears (21, 22, 23, 24) is designed to convey a respective printing filament to the filament outlet nozzle (5), so that the drive movement can be transferred to one of the printing filaments, so that the printing filaments can be selectively fed to the filament outlet nozzle (5).

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