Printhead assembly and stereolithography printer

Abstract

This application relates to a printhead assembly and a 3D printer. The printhead assembly includes a heat dissipation unit and a heating unit spaced apart along a first direction; a heat insulation unit disposed between the heat dissipation unit and the heating unit; multiple nozzle units, each of which is sequentially disposed along the first direction through the heating unit, the heat insulation unit, and the heat dissipation unit, and is also spaced apart along a second direction perpendicular to the first direction; a nozzle unit receiving driving force can move along the first direction to a first position; and a switching unit connected to the heat dissipation unit. During the movement of one of the nozzle units along the first direction to the first position, the nozzle unit can push the switching unit to move in the second direction, so that the nozzle unit not receiving driving force and currently in the first position can move along the first direction to the second position. This application enables high-speed printing and waste-free printing, and effectively protects the model and the nozzle units.

Description

Technical Field

[0001] This application relates to the field of stereoscopic printing, and in particular to a printhead assembly and a stereoscopic printer. Background Technology

[0002] In fused deposition modeling (FDM), thermoplastic filament is melted through a heated nozzle and deposited layer by layer onto a printing platform to form a three-dimensional model.

[0003] Some 3D printers on the market can print on multiple materials or in multiple colors. Among them, the common 3D printers have a structure with multiple feed inlets and a single nozzle. When changing consumables, it is necessary to cut off and pull back the consumables that were used earlier. Moreover, since there is residual molten waste in the nozzle cavity, the waste needs to be cleaned up. This structure not only wastes a lot of consumables, but also has a long material change time, which affects printing efficiency. Utility Model Content

[0004] This application provides a printhead assembly and a 3D printer, which can achieve high-speed printing and waste-free printing, and can also effectively protect the model and nozzle unit.

[0005] In a first aspect, the printhead assembly provided in the embodiments of this application includes:

[0006] Heat dissipation units and heating units are spaced apart along a first direction;

[0007] A heat insulation unit is disposed between the heat dissipation unit and the heating unit;

[0008] Multiple nozzle units, each of which is sequentially disposed along a first direction through the heating unit, the heat insulation unit, and the heat dissipation unit, are also sequentially spaced along a second direction perpendicular to the first direction. Each nozzle unit receiving a driving force can move along the first direction to a first position.

[0009] A switching unit is connected to the heat dissipation unit;

[0010] During the process of one of the nozzle units moving to the first position along the first direction, the nozzle unit can push the switching unit to move in the second direction, so that the nozzle unit that does not receive the driving force and is in the first position can move to the second position along the first direction.

[0011] In some embodiments, the heating unit includes a temperature equalization element and a heating element. The temperature equalization element has a plurality of first heat insulation gaps that are evenly spaced in the second direction. Each of the first heat insulation gaps penetrates the temperature equalization element in a third direction perpendicular to the first direction and the second direction, so as to divide the temperature equalization element into a plurality of heat-conducting parts. The heat-conducting parts are correspondingly arranged with nozzle units, and the nozzle units are inserted into the corresponding heat-conducting parts.

[0012] In some embodiments, the heat insulation unit includes a second heat insulation gap disposed between the heating unit and the heat dissipation unit in the first direction.

[0013] In some embodiments, the heat insulation unit further includes a heat insulation plate disposed within the second heat insulation gap, the heat insulation plate being connected between the heating unit and the heat dissipation unit.

[0014] In some embodiments, the printhead assembly further includes a drive unit and a material delivery unit, wherein the material delivery unit and the nozzle unit are arranged in a one-to-one correspondence in the first direction, and the drive unit is used to drive the corresponding material delivery unit to deliver consumables to the corresponding nozzle unit along the first direction;

[0015] Consumables conveyed along the first direction are used to provide the driving force.

[0016] In some embodiments, the nozzle unit includes a nozzle head and a first reset member, and the switching unit includes a limiting member and a second reset member;

[0017] The nozzle component is used to receive the driving force, and the nozzle component is also used to push the limiting member to move to a third position along a second direction perpendicular to the first direction;

[0018] The limiting member in the third position is used to release the nozzle component, so that the nozzle component, which is not receiving the driving force and is in the first position, moves to the second position under the action of the first reset member;

[0019] The second reset member is used to drive the limiting member in the third position to move to the fourth position, so as to restrict the nozzle unit that receives the driving force and is in the first position to the first position.

[0020] In some embodiments, the nozzle assembly includes a delivery tube and a first limiting body fixed to the delivery tube;

[0021] The limiting member includes a second limiting body and a limiting groove, which are respectively provided in one-to-one correspondence with the first limiting body. The limiting groove is located on one side of the second limiting body in the second direction.

[0022] During the process of the nozzle component moving from the second position to the first position, the first limiting body can push the corresponding second limiting body to move along the second direction, so that the limiting component moves from the fourth position to the third position, thereby allowing the first limiting body to move in the first direction to align with the limiting groove. The second resetting member is used to push the limiting component from the third position to the fourth position, so that the second limiting body restricts the first limiting body within the limiting groove.

[0023] In some embodiments, the second limiting body includes a protrusion and a recess arranged sequentially in the first direction. The width of the protrusion gradually increases along the direction close to the recess. The protrusion and the recess together form the limiting groove. The limiting groove has a first groove surface perpendicular to the first direction and a second groove surface perpendicular to the second direction. The first groove surface is the interface between the protrusion and the recess in the first direction, and the second groove surface is one side surface of the recess in the second direction. The second limiting body also has a guide surface, which is the side surface of the protrusion away from the recess in the first direction.

[0024] During the process of the nozzle component moving from the second position to the first position, the first limiting body abuts against the guide surface and moves to be confined between the first groove surface and the second groove surface.

[0025] In some embodiments, the limiting member further includes a base, the limiting member protruding from the base in the first direction, the second limiting member and the base together forming the limiting groove, and the first limiting member of the nozzle member in the first position abutting against the base.

[0026] In some embodiments, the printhead assembly further includes a connector fixed to the heat dissipation unit, the connector having an assembly slot;

[0027] The switching unit is connected to the heat dissipation unit via the connector. The base is confined within the assembly slot and can move relative to the connector in the second direction. The second reset member is confined within the assembly slot, and one end of the second reset member abuts against the base and the other end abuts against the connector in the second direction.

[0028] In some embodiments, the limiting member further includes a first guide and a second guide respectively fixed to both ends of the base in the second direction, the first guide and the second guide respectively passing through the connector along the second direction, and the second reset member sleeved on the first guide.

[0029] In some embodiments, the printhead assembly further includes a shielding unit that corresponds one-to-one with the nozzle unit;

[0030] The shielding unit has a first end and a second end disposed opposite to each other in the first direction, and the first end of the shielding unit is connected to the heating unit;

[0031] When the corresponding nozzle unit is in the second position, the outlet of the nozzle unit is blocked by the second end of the blocking unit;

[0032] When the corresponding nozzle unit is in the first position, the discharge port of the nozzle unit is exposed at the second end of the shielding unit.

[0033] In some embodiments, the blocking unit is elastic;

[0034] During the process of the corresponding nozzle unit moving to the first position, the nozzle unit pushes the second end of the blocking unit to move away from the discharge port of the nozzle unit;

[0035] During the process of the corresponding nozzle unit moving to the first position, the second end of the shielding unit moves towards the discharge port of the nozzle unit under its own elastic action.

[0036] In some embodiments, along the first end to the second end of the shielding unit, the shielding unit includes a first elastic arm, a second elastic arm, a third elastic arm and a fourth elastic arm connected in sequence, wherein the first elastic arm extends along the first direction, the second elastic arm extends obliquely along a direction away from the heating unit, the third elastic arm extends obliquely along a direction close to the heating unit, and the fourth elastic arm extends along a third direction perpendicular to the first direction and the second direction.

[0037] Secondly, the stereo printer provided in the embodiments of this application includes the printhead assembly provided in any of the above embodiments.

[0038] Compared with the prior art, the beneficial effects of the embodiments of this application are as follows: The printhead assembly and 3D printer include a heat dissipation unit and a heating unit spaced apart along a first direction; a heat insulation unit disposed between the heat dissipation unit and the heating unit; multiple nozzle units, each of which is sequentially disposed through the heating unit, the heat insulation unit, and the heat dissipation unit along the first direction, and the multiple nozzle units are sequentially spaced apart along a second direction perpendicular to the first direction; the nozzle unit receiving driving force can move to a first position along the first direction; and a switching unit connected to the heat dissipation unit; during the process of one of the nozzle units moving to the first position along the first direction, the nozzle unit can push the switching unit to move in the second direction, so that the nozzle unit not receiving driving force and in the first position can move to the second position along the first direction; through the implementation of this application, each nozzle unit delivers its corresponding consumables, and when switching consumables... This process avoids waste, saves material replacement time, improves printing efficiency, and enables high-speed and waste-free printing. Furthermore, during the movement of one nozzle unit to its first position along the first direction, the nozzle unit can push the switching unit to move in the second direction, preventing the switching unit from contacting the nozzle units in the first direction. This allows the nozzle unit not receiving driving force and currently in the first position to move to the second position along the first direction. This effectively protects the model and nozzle units from collisions between nozzle units not currently involved in printing and the printed model, preventing model adhesion and damage. Moreover, the heat dissipation unit and heating unit are spaced apart along the first direction, with a heat insulation unit positioned between them. This effectively prevents heat transfer from the heating unit to the heat dissipation unit, thus preventing thermal creep of the consumables. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of the printhead assembly structure according to an embodiment of this application, wherein all nozzle units are in the second position;

[0040] Figure 2 for Figure 1 The diagram shows a partial structural representation of the printhead assembly.

[0041] Figure 3 for Figure 2 The front view;

[0042] Figure 4 for Figure 3 Top view;

[0043] Figure 5 for Figure 4 A partial structural schematic diagram of the AA cross-section;

[0044] Figure 6 for Figure 3 The right view;

[0045] Figure 7 This is a schematic diagram of the first state structure of the printhead assembly according to an embodiment of this application;

[0046] Figure 8 This is a schematic diagram of the second state structure of the printhead assembly according to an embodiment of this application;

[0047] Figure 9 This is a schematic diagram of the third state structure of the printhead assembly according to an embodiment of this application;

[0048] Figure 10 This is a schematic diagram of the fourth state structure of the printhead assembly according to an embodiment of this application;

[0049] Figure 11 This is a schematic diagram of the fifth state structure of the printhead assembly according to an embodiment of this application;

[0050] Figure 12 This is a schematic diagram of the sixth state structure of the printhead assembly according to an embodiment of this application;

[0051] Figure 13 This is a schematic diagram of the seventh state structure of the printhead assembly according to an embodiment of this application;

[0052] Figure 14 This is a schematic diagram of the eighth state structure of the printhead assembly according to an embodiment of this application;

[0053] Figure 15 This is a schematic diagram of the ninth state structure of the printhead assembly according to an embodiment of this application;

[0054] Figure 16 This is a schematic diagram of the nozzle unit structure in the printhead assembly of an embodiment of this application;

[0055] Figure 17 This is a schematic diagram of the switching unit structure in the printhead assembly of this application embodiment;

[0056] Wherein: 1- Nozzle unit (1a- Nozzle unit, 1b- Nozzle unit, 1c- Nozzle unit, 1d- Nozzle unit, 101- Nozzle head component (1011- Conveying pipe body (10111- Extrusion hole (101111- First hole section, 101112- First hole section, 101113- Feed inlet, 101114- Discharge outlet)), 1012- First limiting body, 1013- Connecting body), 102- First reset component), 2- Switching unit (201- Limiting component (2011- Second limiting body (20111- Protrusion, 20112- Recess, 20113- Guide surface), 2012- Limiting groove (20121- First groove surface, 20122- Second groove surface, 20123- Third groove surface), 2013- Base (20131- Displacement hole), 2014- First guide body, 2 015-Second guide body, 2016-Reset body, 202-Second reset component, 3-Consumables, 4-Drive unit, 5-Heat dissipation unit (501-Feeding hole, 502-Step surface, 503-Heat dissipation fin), 6-Connector (601-Assembly slot), 7-Heating unit (701-Temperature equalization component (7011-First heat insulation gap, 7012-Heat conduction part (70121-Heating hole))), 8-Shielding unit (801-First end, 802-Second end, 803-First elastic arm, 804-Second elastic arm, 805-Third elastic arm, 806-Fourth elastic arm), 9-Heat insulation unit (901-Second heat insulation gap, 902-Heat insulation plate), 10-Housing, 11-Material conveying unit (1101-First conveying wheel, 1102-Second conveying wheel, 1103-Conveying channel). Detailed Implementation

[0057] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings. Preferred embodiments of this application are shown in the drawings. However, this application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of this application.

[0058] It should be noted that when a component is said to be "fixed to" another component, it can be directly attached to the other component or there may be an intervening component. When a component is said to be "connected to" another component, it can be directly connected to the other component or there may be an intervening component.

[0059] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0060] Please refer to Figures 1 to 17 This application embodiment of the printhead assembly includes a nozzle unit 1, a switching unit 2, a heat dissipation unit 5, a heating unit 7, and a heat insulation unit 9. There are multiple nozzle units 1, and each nozzle unit 1 is independent of the others. Each nozzle unit 1 can receive a corresponding driving force, meaning that each nozzle unit 1 is used to deliver its corresponding consumable 3. Furthermore, all nozzle units 1 are arranged sequentially along a second direction perpendicular to the first direction. The heat dissipation unit 5 and the heating unit 7 are spaced apart in the first direction, and the heat insulation unit 9 is disposed between the heat dissipation unit 5 and the heating unit 7. The nozzle unit 1 passes sequentially through the heating unit 7, the heat insulation unit 9, and the heat dissipation unit 5 along the first direction. The heating unit 7 can heat the consumable 3 passing through the nozzle unit 1 to a molten state, thereby allowing the nozzle unit 1 to extrude the molten consumable 3. The nozzle unit 1 can move forward along the first direction to a first position, and the nozzle unit 1 can also move backward along the first direction to a second position. Figures 1 to 3 ,as well as Figures 6 to 7 The second position shown indicates that the nozzle unit 1 receiving driving force can move forward along the first direction to the first position, and the nozzle unit 1 in the first position can be used to extrude consumable 3. The switching unit 2 is connected to the heat dissipation unit 5. During the process of one of the nozzle units 1 moving forward along the first direction to the first position, the nozzle unit 1 can push the switching unit 2 to move in the second direction, so that the switching unit 2 does not abut against each nozzle unit 1 in the first direction, thereby allowing the nozzle unit 1 that does not receive driving force and is in the first position to move along the first direction to the second position, and the nozzle unit 1 in the second position does not extrude consumable 3.

[0061] In this embodiment, each nozzle unit 1 delivers its corresponding consumable 3, meaning that each consumable 3 does not need to share a single nozzle unit 1. When switching consumable 3, there is no need to first cut off and retract the previously extruded consumable 3 and then replace it with a new one, saving material changing time, improving printing efficiency, and enabling high-speed printing. When switching consumable 3, there is also no need to remove residual consumable 3 from the nozzle unit 1, enabling waste-free printing. Furthermore, during the process of one nozzle unit 1 moving forward along the first direction to the first position, the nozzle unit 1 can push the switching unit 2 to move in the second direction, so that the switching unit 2 does not abut against each nozzle unit 1 in the first direction. This allows the nozzle unit 1, which is not receiving driving force and is in the first position, to move along the first direction to the second position. This effectively protects the model and nozzle unit 1 from collisions between the nozzle unit 1 that is not currently participating in printing and the printed model, preventing the model from adhering to the nozzle unit 1 and the model from being damaged. Furthermore, the heat dissipation unit 5 and the heating unit 7 are spaced apart along the first direction, and the heat insulation unit 9 is located between the heat dissipation unit 5 and the heating unit 7, which can effectively prevent the heat from the heating unit 7 from being conducted to the heat dissipation unit 5, thereby preventing the thermal creep of the consumable 3.

[0062] As an example, the printhead assembly also includes a housing 10. When the nozzle unit 1 is in the first position, the outlet 101114 of the nozzle unit 1 extends out of the housing 10, and the length of the outlet 101114 extending out of the housing 10 is L1. Please refer to... Figure 1 When the nozzle unit 1 is in the second position, the outlet 101114 of the nozzle unit 1 is housed in the housing 10, or the outlet 101114 of the nozzle unit 1 extends out of the housing 10 by a length of L2, where L2 is less than L1. This reduces the risk of operators accidentally touching the nozzle unit 1 and improves safety.

[0063] In some implementations, the driving force is parallel to the first direction. For example, the driving force can be a thrust parallel to the first direction.

[0064] In one implementation, the printhead assembly further includes a drive unit 4 and a material delivery unit 11, which are respectively configured one-to-one with the nozzle unit 1. The material delivery unit 11 is configured corresponding to the nozzle unit 1 in a first direction, and is connected to the output end of the corresponding drive unit 4. The drive unit 4 drives the corresponding material delivery unit 11 to deliver the consumable 3 to the corresponding nozzle unit 1 in the forward direction of the first direction. When the consumable 3 is delivered to the nozzle unit 1 in the forward direction of the first direction, the consumable 3 moving in the forward direction of the first direction will press against the nozzle unit 1 in the forward direction of the first direction, thereby pushing the nozzle unit 1 to move to a first position in the forward direction of the first direction. That is, the consumable 3 delivered to the nozzle unit 1 in the forward direction of the first direction can be used to provide driving force. As an example, when the nozzle unit 1 moves to the first position, other structures or other environmental elements on the switching unit 2 will block the nozzle unit 1, preventing the nozzle unit 1 from continuing to move in the forward direction of the first direction. However, since consumable 3 is continuously supplied to the nozzle unit 1 that is printing, consumable 3 always provides driving force to the nozzle unit 1 that is printing, thus ensuring that the nozzle unit 1 remains in the first position and does not return to the second position. Even if the switching unit 2 suddenly malfunctions and moves to a position outside the movement path of the nozzle unit 1, the driving force provided by consumable 3 will allow the nozzle unit 1 to remain in the first position for printing, ensuring printing stability and further preventing the nozzle unit 1 from accidentally resetting to the second position during printing.

[0065] As an example, please refer to Figure 1 The drive unit 4 may include a motor. It is understood that the drive unit 4 may also have other structures, which can be set according to the actual situation, and will not be elaborated here.

[0066] As an example, the material conveying unit 11 may include a first conveying wheel 1101 and a second conveying wheel 1102 spaced apart, with the first conveying wheel 1101 connected to the output end of the drive unit. The gap between the first conveying wheel 1101 and the second conveying wheel 1102 is configured as a conveying channel 1103, which is used to extrude consumables along the first direction. It is understood that the material conveying unit 11 in this example is prior art, and the material conveying unit 11 may also have other structures, which can be set according to actual conditions, and will not be described in detail here.

[0067] It should be noted that in other implementations, the driving force can be provided by other mechanisms or manually, which can be set according to the actual situation, and will not be elaborated here.

[0068] In some embodiments, the switching unit 2 can move in the reverse direction of the second direction to a position on the movement path of the nozzle unit 1, wherein the second direction is perpendicular to the first direction. The switching unit 2, located on the movement path of the nozzle unit 1, can block the nozzle unit 1, which is receiving driving force and is in the first position, in the reverse direction of the first direction, ensuring that the nozzle unit 1, receiving driving force and in the first position, cannot reset to the second position in the reverse direction of the first direction. In this embodiment, even if there is insufficient or lost driving force, as long as the switching unit 2 remains on the movement path of the nozzle unit 1, the nozzle unit 1 cannot reset to the second position, improving the stability of the overall structure and preventing the nozzle unit 1, which has not yet completed printing, from accidentally returning to the second position, resulting in ineffective printing. The switching unit 2 can also move in the forward direction of the second direction to a position not located on the movement path of the nozzle unit 1. It is understood that the switching unit 2 not located on the movement path of the nozzle unit 1 will not obstruct the nozzle unit 1 from moving in the reverse direction of the first direction; therefore, the switching unit 2 not located on the movement path of the nozzle unit 1 can release the nozzle unit 1. If nozzle unit 1 no longer receives driving force at this time, that is, nozzle unit 1 has completed the current printing work, nozzle unit 1 can return to the second position in the opposite direction of the first direction and wait for the next printing work.

[0069] In one implementation, during the process of one of the nozzle units 1 receiving driving force and moving to the first position in the positive direction of the first direction, the nozzle unit 1 moving towards the first position in the positive direction of the first direction can push the switching unit 2 to move in the positive direction of the second direction, so that the switching unit 2 is not located on the movement path of the nozzle unit 1. This not only allows the nozzle unit 1 receiving driving force to move smoothly to the first position, but also allows the nozzle unit 1 to be released in the first direction, so that the nozzle unit 1 that has completed the current printing work but is still restricted to the first position by the switching unit 2 can return to the second position without interfering with other nozzle units 1 that are currently printing, thereby effectively protecting the nozzle units 1 that are not currently participating in printing and protecting the model.

[0070] As an example, the printhead assembly works as follows: In the initial state, please refer to... Figure 7 As shown, nozzle units 1a, 1b, 1c, and 1d are all located in the second position, and the switching unit 2 is simultaneously located on the movement path of all nozzle units 1. It can be understood that the movement path of nozzle unit 1 refers to the path taken by each nozzle unit 1 in the first direction between the first and second positions. All movement paths of nozzle units 1 are along the first direction, and the movement paths of each nozzle unit 1 are parallel and do not interfere with each other. When the drive unit 4 and material conveying unit 11 corresponding to nozzle unit 1a begin conveying consumable 3, please refer to... Figure 8 and Figure 9 As shown, nozzle unit 1a moves towards the first position in the positive direction of the first direction under the push of consumable 3. During the movement of nozzle unit 1a towards the first position in the positive direction of the first direction, nozzle unit 1a pushes switching unit 2 to move in the positive direction of the second direction. Therefore, switching unit 2 does not interfere with the movement of nozzle unit 1a to the first position in the positive direction of the first direction. When nozzle unit 1a moves to... Figure 10 After the first position shown, nozzle unit 1a no longer interferes with switching unit 2 in the reverse direction of the second direction, allowing switching unit 2 to return to the movement path of all nozzle units 1 in the reverse direction of the second direction. Please refer to [reference needed]. Figure 11 As shown. When nozzle unit 1a completes its current printing, that is, when the corresponding drive unit 4 stops supplying consumable 3, nozzle unit 1a cannot return to the second position due to the obstruction of switching unit 2. If at this time the drive unit 4 and material delivery unit 11 corresponding to nozzle unit 1b start supplying consumable 3, nozzle unit 1b moves towards the first position in the positive direction of the first direction under the push of consumable 3. During the process of nozzle unit 1b moving towards the first position in the positive direction of the first direction, nozzle unit 1b will push switching unit 2 to move in the positive direction of the second direction to a position that is not located on the movement path of all nozzle units 1. Please refer to [reference needed]. Figure 12As shown, that is, under the action of nozzle unit 1b, switching unit 2 can release nozzle unit 1a, so that nozzle unit 1a can return to the reverse direction in the first direction. Figure 13 The second position shown. When nozzle unit 1b moves to... Figure 14 After the first position shown, the switching unit 2 returns to the moving path of all nozzle units 1 in the reverse direction of the second direction. Please refer to [reference needed]. Figure 15 As shown.

[0071] It should be noted that in other embodiments, the switching unit 2 can also be moved forward along the second direction by other external forces, which can be set according to the actual situation, and will not be elaborated here.

[0072] In one implementation, at most one nozzle unit 1 prints at any given time; for example, at most one nozzle unit 1 receives driving force at any given time. In another implementation, multiple nozzle units 1 can print simultaneously, enabling mixed printing of various consumables 3. For example, if the consumables 3 extruded by multiple nozzle units 1 are of different colors, mixed-color printing can be achieved. Furthermore, multiple nozzle units 1 can start extruding consumables 3 simultaneously or sequentially. It is understood that as long as nozzle unit 1 continues to receive driving force, even if other nozzle units 1 push the switching unit 2 to move in the positive direction of the second direction to a position not located on the movement path of all nozzle units 1, the nozzle unit 1 that continues to receive driving force will not reset to the second position.

[0073] In some implementation methods, please refer to Figures 7 to 15 As shown, the nozzle unit 1 includes a nozzle head 101 and a first reset member 102. Please refer to... Figure 11 In nozzle unit 1a, when nozzle head 101 is in the first position, first reset member 102 is in a compressed state. Please refer to... Figure 11 The nozzle unit 1b, nozzle unit 1b, and nozzle unit 1b, when the nozzle head 101 is in the second position, the first reset member 102 is in the initial state. Please refer to... Figures 7 to 15 As shown, the switching unit 2 includes a limiting member 201 and a second reset member 202. The limiting member 201 can move in the forward direction of the second direction to a third position, and the limiting member 201 can also move in the reverse direction of the second direction to a fourth position. The third position is not located on the movement path of the nozzle unit 1. When the limiting member 201 is in the third position, the second reset member 202 is in a compressed state. Please refer to [reference needed]. Figure 9 and Figure 10 The fourth position is located on the moving path of nozzle unit 1. When the limiting member 201 is in the fourth position, the second reset member 202 is in the initial state. Please refer to [reference needed]. Figure 7 and Figure 11 .

[0074] In this embodiment, the nozzle 101 is used to receive driving force, that is, the nozzle 101 can be used to extrude consumable 3 in the forward direction along the first direction. When the nozzle 101 receives driving force, the nozzle 101 moves towards the first position in the forward direction of the first direction. During this process, the nozzle 101 continuously presses the first reset member 102 in the forward direction of the first direction, so that the first reset member 102 is gradually compressed. Furthermore, the nozzle 101 is also used to push the limiting member 201 to move to the third position in the forward direction of the second direction. The limiting member 201 in the third position can be used to release the nozzle 101, so that the nozzle 101, which is not receiving driving force and is in the first position, is reset to the second position under the elastic force of the first reset member 102. During the process of the limiting member 201 moving to the third position in the forward direction of the second direction, the limiting member 201 continuously presses the second reset member 202 in the forward direction of the second direction, and the second reset member 202 is gradually compressed. When the nozzle 101 moves to the first position, meaning it no longer obstructs the limiting member 201 in the opposite direction of the second direction, the compressed second reset member 202, under its own elastic force, pushes the limiting member 201 to move towards the fourth position in the opposite direction of the second direction. This continues until the second reset member 202 returns to its initial state, at which point the limiting member 201 is in the fourth position. Since the limiting member 201 in the fourth position is located on the movement path of the nozzle unit 1, it ensures that the nozzle unit 1, receiving the driving force and in the first position, remains in the first position and will not accidentally return to the second position.

[0075] In some implementation methods, please refer to Figure 16 The nozzle assembly 101 includes a delivery pipe body 1011 and a first limiting body 1012, the first limiting body 1012 being fixed to the delivery pipe body 1011. Please refer to... Figure 17The limiting member 201 includes a second limiting body 2011 and a limiting groove 2012. The second limiting body 2011 and the limiting groove 2012 are respectively provided in a one-to-one correspondence with the first limiting body 1012 in the first direction. The second limiting body 2011 defines the limiting groove 2012, which is located on the opposite side of the second limiting body 2011 in the second direction. During the process of the nozzle component 101 moving from the second position to the first position, the first limiting body 1012 can push the corresponding second limiting body 2011 to move in the positive direction of the second direction, thereby causing the limiting member 201 to move from the fourth position to the third position, and then causing the first limiting body 1012 to move in the positive direction of the first direction to align with the corresponding limiting groove 2012. When the nozzle component 101 moves to the first position, since the nozzle component 101 no longer abuts against the limiting member 201 in the opposite direction of the second direction, the compressed second reset member 202 can push the limiting member 201 to move from the third position to the fourth position in the opposite direction of the second direction. The second limiting body 2011 of the limiting member 201 in the fourth position just restricts the first limiting body 1012 in the limiting groove 2012. It is not only simple in structure, but also can effectively restrict the nozzle component.

[0076] As one implementation method, please refer to Figure 5 The conveying tube 1011 has an extrusion hole 10111 extending through it in a first direction. The extrusion hole 10111 has an inlet 101113 and an outlet 101114 arranged opposite each other in the first direction. The material conveying unit 11 can convey the consumable 3 from the inlet 101113 into the extrusion hole 10111 in the forward direction of the first direction, and then the conveying tube 1011 extrudes the molten consumable 3 from the outlet 101114. In some examples, along the forward direction of the first direction, the extrusion hole 10111 includes a first hole segment 101111 and a first hole segment 101112 arranged sequentially. The diameter of the first hole segment 101111 can be larger than the diameter of the consumable 3, facilitating the entry of the consumable 3 into the extrusion hole 10111. The second segment 101112 is a tapered hole with an inlet and an outlet opposite to each other. The inlet of the second segment 101112 is connected to the first segment 101111, and the diameter of the inlet of the second segment 101112 is larger than the diameter of the outlet. When the consumable 3 enters the second segment 101112 from the first segment 101111, the consumable 3 abuts against the wall of the second segment 101112, generating a positive force in the first direction on the delivery tube 1011. This force acts as the driving force, causing the nozzle 101 that has not reached the first position to move toward the first position, or causing the nozzle 101 that is in the first position to remain in the first position.

[0077] It should be noted that in other embodiments, the conveying pipe 1011 can also be other structures, which can be set according to the actual situation.

[0078] As one implementation method, please refer to Figure 16 The first limiting body 1012 can be a protrusion extending from the surface of the conveying pipe 1011 in a third direction, with the third direction perpendicular to the first and second directions. Please refer to... Figure 17 The second limiting body 2011 includes a protrusion 20111 and a recess 20112, which are sequentially arranged along the positive direction of a first direction. The protrusion 20111 protrudes from the recess 20112 on the opposite side of the second direction. The width of the protrusion 20111 gradually increases along the positive direction of the first direction. The protrusion 20111 and the recess 20112 together form a limiting groove 2012, which has an integral first groove surface 20121 and a second groove surface 20122. The first groove surface 20121 is the interface between the protrusion 20111 and the recess 20112 in the first direction and is perpendicular to the first direction. The second groove surface 20122 is the surface of the recess 20112 on the opposite side of the second direction and is perpendicular to the second direction. The second limiting body 2011 also has a guide surface 20113, which is the surface of the protrusion 20111 opposite to the first direction. The guide surface 20113 is set at an angle relative to the second direction. Therefore, during the movement of the nozzle 101 along the first direction, the nozzle 101 abutting against the guide surface 20113 can push the limiting body 201 to move along the second direction. During the movement of the nozzle 101 from the second position to the first position, the first limiting body 1012 abuts against the guide surface 20113 and moves to be confined between the first groove surface 20121 and the second groove surface 20122.

[0079] As an example, taking nozzle unit 1a as an example, the working principle of the printhead assembly is as follows: Please refer to Figure 7 In the initial state, the nozzle head 101 of the nozzle unit 1a is in the second position. At this time, the first limiting body 1012 can abut against the guide surface 20113, or the first limiting body 1012 can have a certain gap with the guide surface 20113. Please refer to... Figure 8 When the nozzle head 101 of the nozzle unit 1a moves towards the first position in the positive direction of the first direction under the push of the consumable 3, during the movement of the nozzle head 101 towards the first position in the positive direction of the first direction, the first limiting body 1012 of the nozzle unit 1a abuts against the guide surface 20113, pushing the limiting member 201 to move in the positive direction of the second direction. Figure 9 The third position shown. When the nozzle head 101 of nozzle unit 1a moves to... Figure 10When the nozzle unit 1a is in the first position, the first limiting body 1012 no longer abuts against the guide surface 20113. At this time, the nozzle head 101 of the nozzle unit 1a no longer interferes with the limiting member 201 in the opposite direction of the second direction. Therefore, the limiting member 201 can return to the opposite direction of the second direction under the action of the second reset member 202. Figure 11 The fourth position is shown. During the process of the limiting member 201 moving in the reverse direction along the second direction to the fourth position, the limiting groove 2012 of the limiting member 201 gradually coincides with the first limiting body 1012 of the nozzle unit 1 in the first direction. Until the limiting member 201 moves to the fourth position, the first limiting body 1012 of the nozzle unit 1a is precisely confined between the first groove surface 20121 and the second groove surface 20122. Please refer to... Figure 11 As shown.

[0080] Understandably, when the printhead 101 is printing normally, the first groove surface 20121 and the first limiting body 1012 can have a gap in the first direction to prevent the extended printhead 101 from accidentally interfering with the limiting body 201 moving in the opposite direction to the fourth position. Alternatively, when the printhead 101 is printing normally, the first groove surface 20121 and the first limiting body 1012 can be in contact in the first direction, thereby further improving the fitting accuracy between the printhead 101 and the limiting body 201 and improving the stability of the overall structure. Similarly, when the printhead 101 is printing normally, the second groove surface 20122 and the first limiting body 1012 can have a gap in the second direction, or the second groove surface 20122 and the first limiting body 1012 can be in contact in the second direction. This can be set according to the actual situation and will not be elaborated here.

[0081] As one implementation method, please refer to Figures 2 to 5The heat dissipation unit 5 has a feed hole 501 corresponding to each nozzle unit 1. The feed tube 1011 of each nozzle unit 1 passes through the corresponding feed hole 501, resulting in better heat dissipation and effectively preventing mutual interference between adjacent nozzle units 1. An annular stepped surface 502 is formed on the wall of the feed hole 501, and the stepped surface 502 is arranged in the opposite direction to the first direction. The nozzle component 101 also includes a connector 1013, which is fixedly sleeved on the outside of the feed tube 1011 and protrudes from the feed tube 1011 around the first direction. A first limiting body 1012 is fixed to the connector 1013 and protrudes from the connector 1013 in the third direction. A first resetting member 102 is sleeved on the feed tube 1011 and is restricted between the stepped surface 502 and the connector 1013. As the nozzle 101 moves toward the first position in the positive direction of the first direction, the distance between the connecting body 1013 and the step surface 502 gradually decreases because the step surface 502 remains fixed, thereby gradually compressing the first reset member 102. Since the step surface 502 is formed within the feed hole 501, that is, the first reset member 102 is at least partially housed within the feed hole 501, the stability of the first reset member 102 can be improved.

[0082] As an example, please refer to Figures 2 to 5 The heat dissipation unit 5 may include a heat sink 503, and a feed hole 501 is formed on the heat sink 503. The heat dissipation unit 5 may also include a cooling fan (not shown in the figure) fixed to the heat sink 503, which can be set according to the actual situation, and will not be described in detail here.

[0083] In some implementation methods, please refer to Figure 17 The limiting member 201 also includes a base 2013, and a second limiting body 2011 is formed on the side of the base 2013 opposite to the first direction. The second limiting body 2011 and the limiting member 201 together form a limiting groove 2012, which also includes a third groove surface 20123. The surface of the base 2013 perpendicular to the first direction and facing the opposite side of the first direction is constructed as the third groove surface 20123. When the nozzle 101 moves to the first position, the third groove surface 20123 abuts against the first limiting body 1012 of the nozzle 101 in the positive direction of the first direction, preventing the nozzle 101 from continuing to move in the positive direction of the first direction under the action of the driving force, thus avoiding excessive extension of the nozzle.

[0084] As one implementation method, please refer to Figure 16 Each nozzle component 101 may include two first limiting bodies 1012, which are symmetrically arranged in a third direction. That is, each nozzle component 101 corresponds to two second limiting bodies 2011, which are symmetrically arranged in a third direction. Please refer to [reference needed]. Figure 17 The second limiting body 2011 cooperates with the corresponding first limiting body 1012, which improves the fitting accuracy between the printhead 101 and the limiting body 201, making the printhead 101 more stable during the printing process, improving the printing quality, and also making the limiting body 201 move more stably along the second direction.

[0085] As an example, the substrate 2013 can be a hollow frame structure, with a clearance hole 20131 in the middle of the substrate 2013, and the nozzle 101 passing through the clearance hole 20131. Each nozzle 101 includes two first limiting bodies 1012 symmetrically arranged in the third direction, and two second limiting bodies 2011 corresponding to the same nozzle 101 are symmetrically arranged on both sides of the clearance hole 20131 in the third direction.

[0086] As one implementation method, please refer to Figure 2 The printhead assembly also includes a connector 6, which is fixed to the heat dissipation unit 5. The connector 6 has an assembly groove 601 that extends through the connector 6 along a first direction. The switching unit 2 is connected to the heat dissipation unit 5 via the connector 6. The base 2013 is confined within the assembly groove 601 and is movable relative to the connector 6 along a second direction. The second reset member 202 is confined within the assembly groove 601, with one end of the second reset member 202 in the opposite direction abutting against the base 2013 and the other end of the second reset member 202 in the forward direction abutting against the connector 6. When the limiting member 201 moves toward the third position along the forward direction of the second direction, the second reset member 202 is gradually compressed by the base 2013 into a compressed state because the connector 6 remains stationary.

[0087] As one implementation method, please refer to Figure 17 The limiting member 201 also includes a first guide body 2014 and a second guide body 2015. The first guide body 2014 is fixed to one end of the base 2013 in the positive direction of the second direction, and the second guide body 2015 is fixed to one end of the base 2013 in the opposite direction of the second direction. Furthermore, the first guide body 2014 and the second guide body 2015 are respectively inserted through the connecting member 6 along the second direction. That is, during the movement of the limiting member 201 along the second direction, the connecting member 6 guides the limiting member 201, allowing it to move more stably along the second direction. The second reset member 202 is sleeved on the first guide body 2014. That is, during the compression of the second reset member 202 and during its return to its initial state, the first guide body 2014 guides the second reset member 202, improving its stability.

[0088] As an example, please refer to Figures 1 to 4The limiting member 201 may further include a reset body 2016. One end of the second guide 2015, away from the base 2013, protrudes outside the connector 6, and the reset body 2016 is fixed to the end of the second guide 2015 away from the base 2013. Pushing the reset body 2016 in the positive direction along the second direction can move the limiting member 201 to a third position in the positive direction along the second direction, so that the printhead assembly 101, which is not receiving driving force and is in the first position, can move to the second position under the action of the first reset member 102. In some examples, the reset body 2016 can be pushed manually. Alternatively, the printhead assembly can be selectively brought close to the environmental element, causing the environmental element to push the reset body 2016 in the positive direction along the second direction.

[0089] In some implementation methods, please refer to Figure 3 and 6 The printhead assembly includes a heating unit 7, which includes a heat equalization element 701 and a heating element (not shown). The heat equalization element 701 has several first heat insulation gaps 7011, each penetrating the heat equalization element 701 along a third direction. All the first heat insulation gaps 7011 are evenly spaced along a second direction to divide the heat equalization element 701 into multiple heat-conducting sections 7012, facilitating independent heating of each heat-conducting section 7012 as needed and reducing mutual interference. Each heat-conducting section 7012 corresponds to a nozzle unit 1, with the nozzle unit 1 passing through the corresponding heat-conducting section 7012. The heating element is fixed to the heat equalization element 701, and the heating element corresponds to each nozzle unit 1. The heat-conducting section 7012 is used to evenly transfer the heat generated by the heating element to the corresponding nozzle unit 1, thereby evenly heating and melting the consumable 3 within the corresponding nozzle unit 1.

[0090] As an example, please refer to Figure 5 The heat-conducting part 7012 has heating holes 70121 that correspond one-to-one with the conveying pipe body 1011.

[0091] As an example, the temperature equalization element 701 can be a block structure made of copper. The heating element can be a PTC (Positive Temperature Coefficient) heater. It is understood that in other embodiments, the temperature equalization element 701 can be made of other materials or have other shapes. The heating element can also be other heaters, which can be set according to the actual situation, and will not be elaborated here.

[0092] It is understood that in other embodiments, the heating unit 7 may also be configured in a one-to-one correspondence with the nozzle unit 1, which can be configured according to the actual situation, and will not be elaborated here.

[0093] In some implementation methods, please refer to Figure 5 and Figure 6 The heat insulation unit 9 includes a second heat insulation gap 901 disposed in the first direction between the heating unit 7 and the heat dissipation unit 5, thereby effectively preventing the heat from the heating unit 7 from being transferred to the heat dissipation unit 5.

[0094] As one implementation method, please refer to Figure 5 and Figure 6 The heat insulation unit 9 also includes a heat insulation plate 902 disposed in the second heat insulation gap 901, and the heat insulation plate 902 is connected between the heating unit 7 and the heat dissipation unit 5.

[0095] In some implementation methods, please refer to Figures 1 to 3 ,and Figure 6 and Figure 5 The printhead assembly also includes a blocking unit 8, which is configured in a one-to-one correspondence with the nozzle unit 1. The blocking unit 8 has a first end 801 and a second end 802 disposed opposite each other in a first direction. The first end 801 of the blocking unit 8 is connected to the heating unit 7. Please refer to [reference needed]. Figure 6 and Figure 5 When the corresponding nozzle unit 1 is in the second position, the outlet 101114 of the nozzle unit 1 is blocked by the second end 802 of the blocking unit 8. After switching nozzle unit 1, the non-working nozzle unit 1 will still have heat and residual consumables that overflow, and the blocking unit 8 can block the overflowing waste. That is to say, the nozzle unit 1 that is not currently printing is blocked by the blocking unit 8, which not only protects the nozzle unit 1, but also prevents the consumables 3 in the non-printing nozzle unit 1 from accidentally overflowing onto the printing platform, thus preventing nozzle unit 1 from leaking glue. The outlet 101114 of the nozzle unit 1 in the first position is exposed at the second end 802 of the blocking unit 8, so the blocking unit 8 will not interfere with the normal printing of the nozzle unit 1.

[0096] In one implementation, the blocking unit 8 is elastic. During the movement of the corresponding nozzle unit 1 to the first position, the nozzle unit 1 can push the second end 802 of the corresponding blocking unit 8 towards the discharge port 101114 away from the nozzle unit 1, thereby allowing the discharge port 101114 of the nozzle unit 1 to protrude from the second end 802 of the blocking unit 8 to extrude the consumable 3. During the movement of the corresponding nozzle unit 1 to the first position, the second end 802 of the blocking unit 8 can move towards the discharge port 101114 of the nozzle unit 1 under its own elasticity, until the discharge port 101114 of the nozzle unit 1 is blocked in the positive upward direction of the first direction by the blocking unit 8. This not only has a simple structure but also effectively protects the nozzle unit 1.

[0097] As an example, the blocking unit 8 can be a spring clip. Please refer to... Figure 6Along the first end 801 to the second end 802 of the shielding unit 8, the shielding unit 8 includes a first elastic arm 803, a second elastic arm 804, a third elastic arm 805 and a fourth elastic arm 806 connected in sequence. The first elastic arm 803 extends along a first direction, the second elastic arm 804 extends obliquely in a direction away from the heating unit 7, the third elastic arm 805 extends obliquely in a direction close to the heating unit 7, and the fourth elastic arm 806 extends along a third direction. This not only effectively shields the unprinted nozzle unit 1, but also effectively prevents the shielding unit 8 from breaking after repeated use, thus extending the service life of the shielding unit 8.

[0098] This application includes the printhead assembly provided in any of the above embodiments.

[0099] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0100] The above embodiments merely illustrate preferred implementations of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the scope of protection of this application. Therefore, the scope of protection of this patent application should be determined by the appended claims.

Claims

1. A printhead assembly, characterized in that, include: Heat dissipation units and heating units are spaced apart along a first direction; A heat insulation unit is disposed between the heat dissipation unit and the heating unit; Multiple nozzle units are provided, each of which is sequentially disposed along a first direction through the heating unit, the heat insulation unit, and the heat dissipation unit. The multiple nozzle units are also sequentially spaced along a second direction perpendicular to the first direction. The nozzle unit receiving the driving force can move along the first direction to a first position. and A switching unit is connected to the heat dissipation unit; During the process of one of the nozzle units moving to the first position along the first direction, the nozzle unit can push the switching unit to move in the second direction, so that the nozzle unit that does not receive the driving force and is in the first position can move to the second position along the first direction.

2. The printhead assembly as claimed in claim 1, characterized in that, The heating unit includes a temperature equalization element and a heating element. The temperature equalization element has a plurality of first heat insulation gaps that are evenly spaced in the second direction. Each of the first heat insulation gaps penetrates the temperature equalization element in a third direction perpendicular to the first direction and the second direction, so as to divide the temperature equalization element into a plurality of heat-conducting parts. The heat-conducting parts are correspondingly arranged with nozzle units, and the nozzle units are inserted into the corresponding heat-conducting parts.

3. The printhead assembly as claimed in claim 1, characterized in that, The heat insulation unit includes a second heat insulation gap disposed between the heating unit and the heat dissipation unit in the first direction.

4. The printhead assembly as claimed in claim 3, characterized in that, The heat insulation unit further includes a heat insulation plate disposed within the second heat insulation gap, and the heat insulation plate is connected between the heating unit and the heat dissipation unit.

5. The printhead assembly as claimed in claim 1, characterized in that, The printhead assembly further includes a drive unit and a material delivery unit. The material delivery unit and the nozzle unit are arranged in a one-to-one correspondence in the first direction. The drive unit is used to drive the corresponding material delivery unit to deliver consumables to the corresponding nozzle unit along the first direction. Consumables conveyed along the first direction are used to provide the driving force.

6. The printhead assembly as claimed in claim 1, characterized in that, The nozzle unit includes a nozzle component and a first reset component, and the switching unit includes a limiting component and a second reset component; The nozzle component is used to receive the driving force, and the nozzle component is also used to push the limiting member to move to a third position along a second direction perpendicular to the first direction; The limiting member in the third position is used to release the nozzle component, so that the nozzle component, which is not receiving the driving force and is in the first position, moves to the second position under the action of the first reset member; The second reset member is used to drive the limiting member in the third position to move to the fourth position, so as to restrict the nozzle unit that receives the driving force and is in the first position to the first position.

7. The printhead assembly as claimed in claim 6, characterized in that, The nozzle assembly includes a delivery pipe body and a first limiting body fixed to the delivery pipe body; The limiting member includes a second limiting body and a limiting groove, which are respectively provided in one-to-one correspondence with the first limiting body. The limiting groove is located on one side of the second limiting body in the second direction. During the process of the nozzle component moving from the second position to the first position, the first limiting body can push the corresponding second limiting body to move along the second direction, so that the limiting component moves from the fourth position to the third position, thereby allowing the first limiting body to move in the first direction to align with the limiting groove. The second resetting member is used to push the limiting component from the third position to the fourth position, so that the second limiting body restricts the first limiting body within the limiting groove.

8. The printhead assembly as claimed in claim 7, characterized in that, The second limiting body includes a protrusion and a recess arranged sequentially in the first direction. The width of the protrusion gradually increases along the direction close to the recess. The protrusion and the recess together form the limiting groove. The limiting groove has a first groove surface perpendicular to the first direction and a second groove surface perpendicular to the second direction. The first groove surface is the interface between the protrusion and the recess in the first direction, and the second groove surface is one side surface of the recess in the second direction. The second limiting body also has a guide surface, which is the side surface of the protrusion away from the recess in the first direction. During the process of the nozzle component moving from the second position to the first position, the first limiting body abuts against the guide surface and moves to be confined between the first groove surface and the second groove surface.

9. The printhead assembly as claimed in claim 7, characterized in that, The limiting member further includes a base, the limiting member protrudes from the base in the first direction, the second limiting body and the base together form the limiting groove, and the first limiting body of the nozzle component in the first position abuts against the base.

10. The printhead assembly as claimed in claim 9, characterized in that, The printhead assembly also includes a connector, which is fixed to the heat dissipation unit and has an assembly slot. The switching unit is connected to the heat dissipation unit via the connector. The base is confined within the assembly slot and can move relative to the connector in the second direction. The second reset member is confined within the assembly slot, and one end of the second reset member abuts against the base and the other end abuts against the connector in the second direction.

11. The printhead assembly as claimed in claim 10, characterized in that, The limiting member further includes a first guide and a second guide, which are respectively fixed to the two ends of the base in the second direction. The first guide and the second guide are respectively inserted through the connector along the second direction, and the second reset member is sleeved on the first guide.

12. The printhead assembly as claimed in claim 1, characterized in that, The printhead assembly also includes a shielding unit that corresponds to each of the nozzle units; The shielding unit has a first end and a second end disposed opposite to each other in the first direction, and the first end of the shielding unit is connected to the heating unit; When the corresponding nozzle unit is in the second position, the outlet of the nozzle unit is blocked by the second end of the blocking unit; When the corresponding nozzle unit is in the first position, the discharge port of the nozzle unit is exposed at the second end of the shielding unit.

13. The printhead assembly as claimed in claim 12, characterized in that, The shielding unit is elastic; During the process of the corresponding nozzle unit moving to the first position, the nozzle unit pushes the second end of the blocking unit to move away from the discharge port of the nozzle unit; During the process of the corresponding nozzle unit moving to the first position, the second end of the shielding unit moves towards the discharge port of the nozzle unit under its own elastic action.

14. The printhead assembly as claimed in claim 13, characterized in that, Along the first end to the second end of the shielding unit, the shielding unit includes a first elastic arm, a second elastic arm, a third elastic arm and a fourth elastic arm connected in sequence, wherein the first elastic arm extends along the first direction, the second elastic arm extends obliquely along a direction away from the heating unit, the third elastic arm extends obliquely along a direction close to the heating unit, and the fourth elastic arm extends along a third direction perpendicular to the first direction and the second direction.

15. A 3D printer, characterized in that, Includes the printhead assembly as described in any one of claims 1 to 14.

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