Actuator and inkjet printing apparatus including the same

Abstract

The actuator includes a motor that provides rotational power, a shaft that receives rotational power from the motor and rotates, converts rotational motion into linear motion, and has a first screw thread at one end, a bellows that is coupled to the motor and fixes the motor and is deformable along the length of the shaft, and a plate coupled to the bellows.

Description

Technology Field

[0001] The present invention relates to an actuator and an inkjet printing device including the same. More specifically, it relates to an actuator used in a display device and an inkjet printing device including the same. Background Technology

[0002] A display device is a device that displays images to provide visual information to users. Among display devices, organic light-emitting diode displays have recently been attracting attention.

[0003] An inkjet printing device may be used when manufacturing a display device. The inkjet printing device may include a plurality of inkjet heads. The inkjet printing device may include an actuator for aligning the inkjet heads to improve the print quality of the display device. The problem to be solved

[0004] One objective of the present invention is to provide an actuator capable of improving print quality.

[0005] Another objective of the present invention is to provide an inkjet printing device comprising the actuator.

[0006] However, the objectives of the present invention are not limited to the objectives described above and may be expanded in various ways without departing from the spirit and scope of the present invention. means of solving the problem

[0007] To achieve one objective of the present invention, an actuator according to embodiments may include a motor that provides rotational power, a shaft that receives rotational power from the motor and rotates, converts rotational motion into linear motion, and has a first screw thread at one end, a bellows that is coupled to the motor, fixes the motor, and is deformable in the longitudinal direction of the shaft, and a plate that is coupled to the bellows.

[0008] In one embodiment, the motor can be fixed to the plate through the bellows.

[0009] In one embodiment, the interior of the bellows can be sealed by the bellows being coupled with the motor and the plate.

[0010] In one embodiment, the motor is positioned on the outside of the shaft and can surround the shaft.

[0011] In one embodiment, the plate may have a second screw thread corresponding to the first screw thread on its inner surface.

[0012] In one embodiment, the first thread of the shaft is screw-coupled to the second thread of the plate, so that the shaft can rotate and move in the longitudinal direction.

[0013] In one embodiment, the motor and the bellows may move linearly only in the longitudinal direction according to the movement of the shaft.

[0014] In one embodiment, the stiffness in the rotational direction with the longitudinal direction of the bellows as the axis may be greater than the stiffness in the longitudinal direction of the bellows.

[0015] In one embodiment, the bellows may be elastically deformable only in the longitudinal direction.

[0016] In one embodiment, the bellows can suppress movement in directions other than linear movement in the longitudinal direction of the motor.

[0017] In one embodiment, the length of the shaft is greater than the length of the motor, and the one end of the shaft having the first screw thread may protrude from the motor, the bellows, and the plate.

[0018] In one embodiment, the actuator may further include a ball coupled to one end of the shaft.

[0019] In one embodiment, the actuator may further include a fixing member that surrounds one end of the shaft and fixes the shaft.

[0020] To achieve another objective of the present invention, an inkjet printing device according to embodiments may include an inkjet head for discharging ink, a motor that aligns the inkjet head, is coupled to the inkjet head, and provides rotational power, a shaft that receives rotational power from the motor and rotates, converts rotational motion into linear motion, and has a first screw thread at one end, an actuator comprising a bellows that is coupled to the motor, fixes the motor, and is deformable in the longitudinal direction of the shaft, and a plate coupled to the bellows, and a switch unit for controlling the actuator.

[0021] In one embodiment, the switch unit may include a relay element electrically connected to the motor.

[0022] In one embodiment, the switch unit may include a transistor electrically connected to the motor.

[0023] In one embodiment, the switch unit receives a pulse signal and can control the movement of the actuator according to the pulse signal.

[0024] In one embodiment, the actuator further includes a ball coupled to one end of the shaft, and the actuator can be coupled to the inkjet head through the ball.

[0025] In one embodiment, the plate has a second thread corresponding to the first thread on its inner surface, and the first thread of the shaft is screw-coupled to the second thread of the plate, so that the shaft can rotate and move in the longitudinal direction.

[0026] In one embodiment, the inkjet head coupled to the shaft can move linearly only in the longitudinal direction by the movement of the shaft. Effects of the invention

[0027] In an actuator according to embodiments of the present invention, the actuator comprises a motor, a shaft, and a bellows, wherein the bellows inhibits movement in the rotational direction of the motor and accommodates incidental movements of the motor, thereby allowing the shaft to move in the longitudinal direction. Since the structure of the actuator can be simplified, the size of the actuator can be reduced.

[0028] In an inkjet printing device according to embodiments of the present invention, the inkjet printing device comprises an inkjet head, an actuator coupled to the inkjet head, and a switch unit for controlling the movement of the actuator, thereby allowing the inkjet head to be aligned using the actuator, which is small in size. Accordingly, the size of the inkjet printing device can be reduced, and the number of inkjet heads that can be integrated into the inkjet printing device can be increased.

[0029] However, the effects of the present invention are not limited to the effects described above and may be extended in various ways without departing from the spirit and scope of the present invention. Brief explanation of the drawing

[0030] FIGS. 1 and FIGS. 2 are front views showing an actuator according to an embodiment of the present invention. FIG. 3 is a perspective view showing an inkjet printing device including the actuator of FIG. 1. Figure 4 is an enlarged front view of area A of Figure 3. FIG. 5 is a perspective view showing the inkjet printing devices of FIG. 3 integrated. FIG. 6 is a block diagram showing an example of the internal system of the inkjet printing device of FIG. 3. Figure 7 is a block diagram showing another example of the internal system of the inkjet printing device of Figure 3. Figure 8 is a block diagram showing another example of the internal system of the inkjet printing device of Figure 3. FIG. 9 is a block diagram showing another example of the internal system of the inkjet printing device of FIG. 3. Specific details for implementing the invention

[0031] Hereinafter, embodiments of the present invention will be described in more detail with reference to the attached drawings. Identical components in the drawings are given the same reference numerals, and redundant descriptions of identical components are omitted.

[0032] FIGS. 1 and 2 are front views showing an actuator according to an embodiment of the present invention. For example, FIGS. 1 and 2 may be front views for explaining a method of operation of an actuator according to an embodiment.

[0033] Referring to FIG. 1, the actuator (10) may include a motor (MT), a shaft (SFT), a bellows (BL), a plate (PL), a ball (BA), and a fixed member (FM).

[0034] The motor (MT) can provide rotational power to the shaft (SFT). The motor (MT) can be positioned on the outside of the shaft (SFT) and can surround the shaft (SFT).

[0035] The motor (MT) may include a rotor and a stator. The rotor may surround the shaft (SFT), and the stator may surround the rotor. The rotor may include a coil, and the stator may include a magnet and a yoke.

[0036] The motor (MT) and the shaft (SFT) can move when the shaft (SFT) moves in the longitudinal direction (D) of the shaft (SFT) through interaction.

[0037] The shaft (SFT) can rotate by receiving rotational power from the motor (MT). The length of the shaft (SFT) in the longitudinal direction (D) may be greater than the length of the motor (MT) in the longitudinal direction (D). Accordingly, the first end (SFTE1) and the second end (SFTE2) of the shaft (SFT) may protrude from the motor (MT). The second end (SFTE2) may be located on the opposite side of the first end (SFTE1), and the length (L1) of the first end (SFTE1) protruding from the motor (MT) may be greater than the length (L2) of the second end (SFTE2) protruding from the motor (MT).

[0038] The shaft (SFT) may have a first thread (ST1) on the first end (SFTE1).

[0039] The bellows (BL) can be coupled with the motor (MT). The plate (PL) can be coupled with the bellows (BL). Therefore, the motor (MT) can be coupled to the plate (PL) through the bellows (BL). The plate (PL) can be fixed and not move. Therefore, the bellows (BL) coupled with the plate (PL) can fix the motor (MT).

[0040] The plate (PL) may have a second screw thread (ST2) on the inner circumference of the plate (PL). The second screw thread (ST2) may correspond to the first screw thread (ST1). The second screw thread (ST2) may be screw-coupled with the first screw thread (ST1).

[0041] The ball (BA) can be coupled to the first end (SFTE1) of the shaft (SFT). The ball (BA) can move in the longitudinal direction (D) according to the movement of the shaft (SFT).

[0042] The fixing member (FM) can surround the first end (SFTE1) of the shaft (SFT) and fix the shaft (SFT). That is, the fixing member (FM) can fix the shaft (SFT) so that the shaft (SFT) moves only in the longitudinal direction (D).

[0043] Referring to FIG. 1 and FIG. 2, FIG. 2 may show the motor (MT) and the shaft (SFT) included in the actuator (10) of FIG. 1 moved in the longitudinal direction (D). In one embodiment, the first end (SFTE1) of the shaft (SFT) having the first thread (ST1) may protrude from the motor (MT), the bellows (BL), and the plate (PL). Thus, the first end (SFTE1) may be exposed.

[0044] The first thread (ST1) of the shaft (SFT) can be screw-coupled to the second thread (ST2) of the plate (PL). By screw-coupled the first thread (ST1) to the second thread (ST2), the shaft (SFT) can rotate. Through this, the shaft (SFT) can move in the longitudinal direction (D). For example, if the first thread (ST1) is screw-coupled to the second thread (ST2) in a clockwise direction, the shaft (SFT) can move in the first direction (D1) (e.g., +Z direction) of the longitudinal direction (D) while rotating. If the first thread (ST1) is screw-coupled to the second thread (ST2) in a counter-clockwise direction, the shaft (SFT) can move in the second direction (D2) (e.g., -Z direction) of the longitudinal direction (D), which is opposite to the first direction (D1) while rotating.

[0045] However, embodiments according to the present invention are not limited thereto. For example, when the first screw thread (ST1) is coupled to the second screw thread (ST2) by rotating clockwise, the shaft (SFT) may move in the second direction (D2), and when the first screw thread (ST1) is coupled to the second screw thread (ST2) by rotating counterclockwise, the shaft (SFT) may move in the first direction (D1).

[0046] Accordingly, the shaft (SFT) can convert rotational motion into linear motion by receiving rotational power from the motor (MT) and rotating and moving.

[0047] The motor (MT) is coupled with the bellows (BL), and the bellows (BL) may be deformable in the longitudinal direction (D). For example, the rigidity of the bellows (BL) in the rotational direction with the longitudinal direction (D) as the axis may be greater than the rigidity of the bellows (BL) in the longitudinal direction (D). Therefore, deformation in the rotational direction with the longitudinal direction (D) as the axis of the bellows (BL) may be suppressed, and elastic deformation in the longitudinal direction (D) may be possible.

[0048] The motor (MT) can move together with the shaft (SFT) as it moves. However, by combining the motor (MT) with the bellows (BL), the bellows (BL) can suppress deformation of the motor (MT) in the rotational direction. That is, the bellows (BL) can suppress movement in directions other than linear motion in the longitudinal direction (D) of the motor (MT) (e.g., rotational direction with the longitudinal direction (D) as an axis). Due to the bellows (BL), the motor (MT) may be deformed only in the longitudinal direction (D). The shaft (SFT) can rotate by receiving rotational power from the motor (MT) and can move in the longitudinal direction (D). At this time, the motor (MT) can move linearly only in the longitudinal direction (D) as the shaft (SFT) moves.

[0049] When the motor (MT) moves linearly in the first direction (D1), the bellows (BL) can be extended in the length direction (D). When the motor (MT) moves linearly in the second direction (D2), the bellows (BL) can be shortened in the length direction (D).

[0050] The bellows (BL) can accommodate other incidental movements of the motor (MT), excluding movement in the longitudinal direction (D). This allows incidental movements of the shaft (SFT) to be eliminated. The incidental movements of the motor (MT) may be movements in directions other than the longitudinal direction (D). By the bellows (BL) accommodating the incidental movements of the motor (MT), the motor (MT) can move linearly only in the longitudinal direction (D), and the shaft (SFT) can also move only in the longitudinal direction (D) and rotate only in a rotational direction with the longitudinal direction (D) as the axis, without any incidental movements.

[0051] In one embodiment, the bellows (BL) accommodates the incidental movements of the motor (MT), so that the power supplied to the actuator (10) is not wasted by the incidental movements.

[0052] In one embodiment, the motor (MT) provides rotational power to the shaft (SFT), and the rotational movement of the motor (MT) is suppressed by the bellows (BL), so that the motor (MT) cannot rotate, and only the shaft (SFT) rotates by the rotational power and can move in the longitudinal direction (D). At this time, as the shaft (SFT) moves, the motor (MT) also moves in the longitudinal direction (D), and the bellows (BL) can accommodate incidental movements excluding the movement of the motor (MT) in the longitudinal direction (D). Therefore, when an object is coupled to the ball (BA) included in the actuator (10), the object can move linearly only in the longitudinal direction (D) without incidental movements.

[0053] The bellows (BL) can be coupled to the motor (MT), and the bellows (BL) can also be coupled to the plate (PL). For example, the bellows (BL) can be coupled to the motor (MT) by welding. The plate (PL) can be coupled to the bellows (BL) by welding. Thus, the joint between the bellows (BL) and the motor (MT) can be sealed. Additionally, the joint between the bellows (BL) and the plate (PL) can be sealed. Therefore, by coupling the bellows (BL) with the motor (MT) and the plate (PL), the interior of the bellows (BL) can be sealed. However, embodiments according to the present invention are not limited thereto, and the method of coupling the bellows (BL) and the motor (MT), and the method of coupling the bellows (BL) and the plate (PL) may not be a welding method.

[0054] When the actuator (10) is operated, foreign matter may occur inside the motor (MT) and the bellows (BL). For example, foreign matter may occur when the first screw thread (ST1) and the second screw thread (ST2) are screw-coupled. Additionally, foreign matter may occur when liquid droplets, such as lubricating oil applied inside the actuator, are scattered.

[0055] By sealing the inside of the bellows (BL), the foreign matter can be trapped inside the bellows (BL). Therefore, by preventing the foreign matter from being released outside the bellows (BL), it is possible to prevent other devices from being contaminated.

[0056] The material constituting the fixed member (FM) may be different from the material constituting the shaft (SFT). Since friction is strong between the same materials, the fixed member (FM) and the shaft (SFT) that come into contact with each other may include different materials. Similarly, since the shaft (SFT) and the plate (PL) come into contact with each other, the material constituting the shaft (SFT) may be different from the material constituting the plate (PL) in order to reduce friction.

[0057] As a result, the frictional force between the shaft (SFT) and the plate (PL) can be reduced, and the shaft (SFT) can rotate and move easily. Therefore, the actuator can operate smoothly.

[0058] In one embodiment, the actuator (10) includes the motor (MT), the shaft (SFT), and the bellows (BL), so that the configuration of the actuator (10) can be simplified and the size of the actuator (10) can be reduced.

[0059] FIG. 3 is a perspective view showing an inkjet printing device including the actuator of FIG. 1, FIG. 4 is a front view enlarged of area A of FIG. 3, and FIG. 5 is a perspective view showing the inkjet printing devices of FIG. 3 integrated.

[0060] Referring to FIGS. 3 to 5, an inkjet printing device (100) may include an inkjet head (IH) and the actuator (10).

[0061] The inkjet head (IH) can eject ink. Specifically, the inkjet head (IH) may include nozzles that eject ink.

[0062] A plurality of actuators (11, 12, 13, 14, 15, 1) may be coupled to the inkjet head (IH). For example, each of the plurality of actuators (11, 12, 13, 14, 15, 16) may be substantially identical to the actuator (10) described with reference to FIGS. 1 and 2. Each of the plurality of actuators (11, 12, 13, 14, 15, 16) may align the inkjet head (IH). The inkjet printing device (100) may include a plurality of the actuators (11, 12, 13, 14, 15, 16) coupled to a single inkjet head (IH) to move and align the inkjet head (IH) in various directions.

[0063] The actuator (10) may include the ball (BA), and the ball (BA) may be coupled to the first end (SFTE1) of the shaft (SFT). The actuator (10) may be coupled to the inkjet head (IH) through the ball (BA) included in the actuator (10). That is, the shaft (SFT) included in the actuator (10) may not come into direct contact with the inkjet head (IH).

[0064] The shaft (SFT) can be coupled to the inkjet head (IH) through the ball (BA), and the shaft (SFT) can transmit a moving force to the inkjet head (IH) through the ball (BA). The inkjet head (IH) can receive a moving force in the longitudinal direction (D) from the actuator (10) and move in the longitudinal direction (D) together with the actuator (10).

[0065] Because the bellows (BL) included in the actuator (10) suppresses the movement of the motor (MT) in the rotational direction and accommodates the incidental movements, the actuator (10) can only move in the longitudinal direction (D).

[0066] Therefore, since the inkjet head (IH) receives only the force to move in the longitudinal direction (D) from the actuator (10) through the ball (BA), the inkjet head (IH) can also move in a straight line only in the longitudinal direction (D).

[0067] The ball (BA) can also accommodate incidental movements of the shaft (SFT). Since the shaft (SFT) transmits the force of movement to the inkjet head (IH) through the ball (BA), the inkjet head (IH) can move in a straight line only in the longitudinal direction (D) without incidental movements.

[0068] FIG. 6 is a block diagram showing an example of an internal system of an inkjet printing device of FIG. 3. For example, FIG. 6 may be a diagram for explaining the operation method of one actuator (10) in the internal system (200) of the inkjet printing device (100) of FIG. 3.

[0069] Referring to FIG. 6, the internal system (200) of the inkjet printing device (100) may include a switch unit (SW1), a control unit (CTR), a power supply (PW), and a camera (CA).

[0070] The switch unit (SW1) can be electrically connected to the actuator (10). The switch unit (SW1) can control the actuator (10).

[0071] The above control unit (CTR) can be electrically connected to the switch unit (SW1) and can provide the pulse signal to the switch unit (SW1).

[0072] The switch unit (SW1) can receive a DC voltage from the power supply (PW). The DC voltage can be supplied to the motor (MT) through the relay element (SSR).

[0073] The camera (CA) can capture the alignment status of the inkjet head (IH). The camera can be electrically connected to the control unit (CTR). The control unit (CTR) can receive an image captured from the camera of the alignment status of the inkjet head (IH).

[0074] The control unit (CTR) can determine whether the inkjet head (IH) is aligned based on the captured image and can measure the degree to which the inkjet head (IH) deviates from a preset position. Through this, the control unit (CTR) can provide the pulse signal for controlling the inkjet head (IH) to the relay element (SSR).

[0075] In one embodiment, the switch unit (SW1) may include a relay element (SSR). The relay element (SSR) may be electrically connected to the motor (MT). The relay element (SSR) may represent a switching means for interrupting the electrical connection of two nodes. For example, the relay element (SSR) may be a contactless relay. The relay element (SSR) may have at least two operating states. For example, the relay element (SSR) may have an ON state and an OFF state.

[0076] The switch unit (SW1) can operate the motor (MT) according to the pulse signal. Specifically, the operating state of the relay element (SSR) may change according to the pulse signal. The operation of the motor (MT), which is electrically connected to the relay element (SSR), may be determined according to the operating state of the relay element (SSR).

[0077] According to the above pulse signal, the actuator (10) including the motor (MT) can move. By the movement of the actuator (10), the inkjet head (IH) coupled to the actuator (10) can also move.

[0078] The actuator (10) can move in the first direction (D1) or the second direction (D2) according to the pulse signal, and the inkjet head (IH) coupled to the actuator (10) can also move in the first direction (D1) or the second direction (D2). Thus, the actuator (10) can align the inkjet head (IH).

[0079] In one embodiment, the inkjet printing device (100) includes the inkjet head (IH), the actuator (10) coupled to the inkjet head (IH), and the switch unit (200) that controls the movement of the actuator (10), so that the inkjet head (IH) can be aligned with the actuator (10) which is small in size, thereby reducing the size of the inkjet printing device (100). Additionally, the number of inkjet heads (IH) that can be integrated into the inkjet printing device (100) can be increased.

[0080] FIG. 7 is a block diagram illustrating another example of the internal system of the inkjet printing device of FIG. 3. For example, FIG. 7 may be a diagram illustrating the operation method of the six actuators (10) in the internal system (210) of the inkjet printing device (100). That is, FIG. 7 may be a diagram illustrating the operation method of the inkjet printing device (100) of FIG. 3 in which the six actuators (10) are coupled to one inkjet head (IH).

[0081] In describing the internal system (210) of the inkjet printing device of FIG. 7, descriptions of configurations that are substantially identical or similar to the internal system (200) of the inkjet printing device of FIG. 6 will be omitted.

[0082] Referring to FIGS. 3, 4, 6, and 7, the internal system (210) of the inkjet printing device (100) may include a switch unit (SW2), a control unit (CTR), a power supply (PW), and a camera (CA).

[0083] The switch unit (SW2) may include first to sixth relay elements (SSR1, SSR2, SSR3, SSR4, SSR5, SSR6). The first to sixth relay elements (SSR1, SSR2, SSR3, SSR4, SSR5, SSR6) may each be electrically connected to the first to sixth motors (MT1, MT2, MT3, MT4, MT5, MT6). The first to sixth motors (MT1, MT2, MT3, MT4, MT5, MT6) may each be included in the first to sixth actuators (11, 12, 13, 14, 15, 16). Each of the first to sixth relay elements (SSR1, SSR2, SSR3, SSR4, SSR5, SSR6) may have at least two operating states. Each of the above first to sixth relay elements (SSR1, SSR2, SSR3, SSR4, SSR5, SSR6) can have an ON state and an OFF state.

[0084] The switch unit (SW2) can receive a DC voltage from the power supply (PW). The DC voltage can be provided to the first to sixth motors (MT1, MT2, MT3, MT4, MT5, MT6) respectively through the first to sixth relay elements (SSR1, SSR2, SSR3, SSR4, SSR5, SSR6) included in the switch unit (SW2).

[0085] The control unit (CTR) can be electrically connected to the switch unit (SW2) and can provide a pulse signal to the switch unit (SW2). The control unit (CTR) can provide a switch signal to the switch unit (SW2). The switch signal can cause the first to sixth relay elements (SSR1, SSR2, SSR3, SSR4, SSR5, SSR6) included in the switch unit (SW2) to sequentially receive the pulse signal. That is, the control unit (CTR) can provide a switch signal to the switch unit (SW2) to control the first to sixth relay elements (SSR1, SSR2, SSR3, SSR4, SSR5, SSR6) included in the switch unit (SW2) with a single control unit (CTR). However, embodiments according to the present invention are not limited thereto, and the control unit (CTR) may provide only the pulse signal without providing the switch signal to the switch unit (SW2).

[0086] The control unit (CTR) can measure the degree to which the inkjet head (IH) deviates from a preset position. Accordingly, the control unit (CTR) can provide different pulse signals to each of the first to sixth relay elements (SSR1, SSR2, SSR3, SSR4, SSR5, SSR6) to align the inkjet head (IH). At this time, different pulse signals can be provided sequentially to each of the first to sixth relay elements (SSR1, SSR2, SSR3, SSR4, SSR5, SSR6) by the switch signal.

[0087] According to the pulse signal, the first to sixth relay elements (SSR1, SSR2, SSR3, SSR4, SSR5, SSR6) can each operate the first to sixth motors (MT1, MT2, MT3, MT4, MT5, MT6). Accordingly, the first to sixth motors (MT1, MT2, MT3, MT4, MT5, MT6) can each operate differently according to the pulse signal and the switch signal. Accordingly, the first to sixth actuators (11, 12, 13, 14, 15, 16), each including the first to sixth motors (MT1, MT2, MT3, MT4, MT5, MT6), may have different movement, direction of movement, and distance of movement.

[0088] Each of the first to sixth actuators (11, 12, 13, 14, 15, 16) can move in the longitudinal direction (D) of each of the first to sixth actuators (11, 12, 13, 14, 15, 16) according to the switch signal and the pulse signal. Through this, the first to sixth actuators (11, 12, 13, 14, 15, 16) can align the inkjet head (IH).

[0089] However, embodiments according to the present invention are not limited thereto, and the number of actuators (10) coupled to one inkjet head may vary.

[0090] In one embodiment, the size of the inkjet printing device (100) can be reduced by including the switch unit (SW2) capable of controlling the movement of the first to sixth actuators (11, 12, 13, 14, 15, 16). Additionally, the actuators (10) connected to the inkjet head (IH) can be controlled by a single switch unit (SW2) by using relay elements (SSR) included in the switch unit (SW2).

[0091] FIG. 8 is a block diagram showing another example of the internal system of the inkjet printing device of FIG. 3. The internal system (300) of the inkjet printing device of FIG. 8 (e.g., the inkjet printing device (100) of FIG. 3) may be identical to the internal system (200) of the inkjet printing device of FIG. 6, except that the switch unit (SW3) includes a transistor (TR) instead of a relay element (the relay element (SSR) of FIG. 6). Therefore, in describing the internal system (300) of the inkjet printing device of FIG. 8, descriptions of configurations that are substantially identical or similar to the internal system (200) of the inkjet printing device of FIG. 6 will be omitted.

[0092] Referring to FIGS. 3, 4, 5, and 8, the internal system (300) of the inkjet printing device (100) may include a switch unit (SW3), a control unit (CTR), a power supply (PW), and a camera (CA).

[0093] The switch unit (SW3) may include the transistor (TR). The transistor (TR) may be electrically connected to the motor (MT). The transistor (TR) may be a semiconductor device that amplifies or acts as a switch by controlling the flow of current or voltage. The transistor (TR) may be composed of a semiconductor material and have at least three terminals that can be connected to an external circuit. When voltage or current is applied to one pair of transistor terminals, the current can be controlled through the other pair of terminals. The transistor (TR) may have at least two operating states. For example, the transistor (TR) may have an ON state and an OFF state.

[0094] The switch unit (SW3) can receive a DC voltage from the power supply (PW). The DC voltage can be provided to the motor (MT) through the transistor (TR), and the operating state of the transistor (TR) can be changed by the pulse signal.

[0095] FIG. 9 is a block diagram illustrating another example of the internal system of the inkjet printing device of FIG. 3. For example, the internal system (310) of the inkjet printing device of FIG. 9 (e.g., the inkjet printing device (100) of FIG. 3) may be identical to the internal system (210) of the inkjet printing device of FIG. 7, except that the switch unit (SW3) includes first to sixth transistors (TR1, TR2, TR3, TR4, TR5, TR6) instead of relay elements (SSR). Therefore, in describing the internal system (310) of the inkjet printing device of FIG. 9, descriptions of configurations that are substantially identical or similar to the internal system (210) of the inkjet printing device of FIG. 7 will be omitted.

[0096] Referring to FIG. 9, the internal system (310) of the inkjet printing device may include a switch unit (SW4), a control unit (CTR), a power supply (PW), and a camera (CA).

[0097] The switch unit (SW4) may include first to sixth transistors (TR1, TR2, TR3, TR4, TR5, TR6). The first to sixth transistors (TR1, TR2, TR3, TR4, TR5, TR6) may each be electrically connected to first to sixth motors (MT1, MT2, MT3, MT4, MT5, MT6). The first to sixth motors (MT1, MT2, MT3, MT4, MT5, MT6) may each be included in first to sixth actuators (11, 12, 13, 14, 15, 16). Each of the first to sixth transistors (TR1, TR2, TR3, TR4, TR5, TR6) may have at least two operating states. Each of the above first to sixth transistors (TR1, TR2, TR3, TR4, TR5, TR6) can have an ON state and an OFF state.

[0098] The switch unit (SW4) can receive a DC voltage from the power supply (PW). The DC voltage can be provided to the first to sixth motors (MT1, MT2, MT3, MT4, MT5, MT6) respectively through the first to sixth relay elements (SSR1, SSR2, SSR3, SSR4, SSR5, SSR6) included in the switch unit (SW4).

[0099] The control unit (CTR) can be electrically connected to the switch unit (SW4) and can provide a pulse signal to the switch unit (SW4). The control unit (CTR) can provide a switch signal to the switch unit (SW4).

[0100] The control unit (CTR) can measure the degree to which the inkjet head (IH) deviates from a preset position. The control unit (CTR) can provide different pulse signals to each of the first to sixth transistors (TR1, TR2, TR3, TR4, TR5, TR6) to align the inkjet head (IH). At this time, different pulse signals can be sequentially provided to each of the first to sixth transistors (TR1, TR2, TR3, TR4, TR5, TR6) by the switch signal.

[0101] According to the pulse signal, the first to sixth transistors (TR1, TR2, TR3, TR4, TR5, TR6) can each operate the first to sixth motors (MT1, MT2, MT3, MT4, MT5, MT6). Accordingly, each of the first to sixth actuators (11, 12, 13, 14, 15, 16), each including the first to sixth motors (MT1, MT2, MT3, MT4, MT5, MT6), may have different movement, direction of movement, and distance of movement.

[0102] Each of the first to sixth actuators (11, 12, 13, 14, 15, 16) can move in the longitudinal direction (D) of each of the first to sixth actuators (11, 12, 13, 14, 15, 16) according to the switch signal and the pulse signal. Through this, the first to sixth actuators (11, 12, 13, 14, 15, 16) can align the inkjet head (IH).

[0103] Although the present invention has been described above with reference to preferred embodiments, those skilled in the art will understand that various modifications and changes can be made to the invention without departing from the spirit and scope of the invention as set forth in the following claims. Industrial applicability

[0104] An actuator according to exemplary embodiments of the present invention and an inkjet printing device including the same can be applied to a display device including a computer, laptop, mobile phone, smartphone, smartpad, PMP, PDA, MP3 player, etc.

[0105] Although the present invention has been described above with reference to embodiments thereof, those skilled in the art will understand that various modifications and changes can be made to the present invention without departing from the spirit and scope of the invention as described in the following claims. Explanation of the symbols

[0106] 10: Actuator 100: Inkjet printing device MT: Motor SFT: Shaft BL: Bellows PL: Plate FM: Fixing member ST1: First thread BA: Ball D: Length direction IH: Inkjet head SW1: Switch unit PW: Power CTR: Control unit CA: Camera

Claims

Claim 1 An actuator comprising: a motor that provides rotational power; a shaft that receives rotational power from the motor and rotates, converts rotational motion into linear motion, and has a first screw thread at one end; a bellows that is coupled to the motor, fixes the motor, and is deformable in the longitudinal direction of the shaft; and a plate coupled to the bellows, wherein the length of the shaft is greater than the length of the motor, the one end of the shaft protrudes from the motor, the bellows, and the plate, and a ball is coupled to the one end of the shaft. Claim 2 An actuator according to claim 1, characterized in that the motor is fixed to the plate through the bellows. Claim 3 An actuator according to claim 1, characterized in that the interior of the bellows is sealed by the bellows being coupled with the motor and the plate. Claim 4 An actuator according to claim 1, wherein the motor is positioned on the outside of the shaft and surrounds the shaft. Claim 5 An actuator according to claim 1, characterized in that the plate has a second screw thread corresponding to the first screw thread on its inner surface. Claim 6 An actuator according to claim 5, characterized in that the first thread of the shaft is screw-coupled to the second thread of the plate, thereby allowing the shaft to rotate and move in the longitudinal direction. Claim 7 An actuator according to claim 6, characterized in that the motor and the bellows move linearly only in the longitudinal direction according to the movement of the shaft. Claim 8 An actuator according to claim 1, characterized in that the rigidity in the rotational direction with respect to the length direction of the bellows is greater than the rigidity in the length direction of the bellows. Claim 9 An actuator according to claim 1, characterized in that the bellows is elastically deformable only in the longitudinal direction. Claim 10 An actuator according to claim 1, wherein the bellows inhibits movement in directions other than linear movement in the longitudinal direction of the motor. Claim 11 An actuator according to claim 1, wherein the length of the shaft is greater than the length of the motor, and the one end of the shaft having the first screw thread protrudes from the motor, the bellows, and the plate. Claim 12 An actuator according to claim 1, further comprising a ball coupled to one end of the shaft. Claim 13 An actuator according to claim 1, further comprising a fixing member that surrounds one end of the shaft and fixes the shaft. Claim 14 An inkjet printing device comprising: an inkjet head for ejecting ink; a motor that aligns the inkjet head and provides rotational power; a shaft that rotates by receiving rotational power from the motor, converts rotational motion into linear motion, and has a first screw thread at one end; a bellows that is coupled to the motor, fixes the motor, and is deformable in the longitudinal direction of the shaft; and a plate coupled to the bellows; and a switch unit for controlling the actuator, wherein the length of the shaft is greater than the length of the motor, the one end of the shaft protrudes from the motor, the bellows, and the plate, and a ball is coupled to the one end of the shaft. Claim 15 An inkjet printing device according to claim 14, wherein the switch portion comprises a relay element electrically connected to the motor. Claim 16 An inkjet printing device according to claim 14, wherein the switch portion comprises a transistor electrically connected to the motor. Claim 17 An inkjet printing device according to claim 14, wherein the switch unit receives a pulse signal and controls the movement of the actuator according to the pulse signal. Claim 18 An inkjet printing device according to claim 14, wherein the actuator further comprises a ball coupled to one end of the shaft, and the actuator is coupled to the inkjet head through the ball. Claim 19 An inkjet printing device according to claim 14, wherein the plate has a second screw thread corresponding to the first screw thread on its inner surface, and the first screw thread of the shaft is screw-coupled to the second screw thread of the plate, so that the shaft rotates and moves in the longitudinal direction. Claim 20 An inkjet printing device according to claim 19, characterized in that the inkjet head coupled to the shaft moves linearly only in the longitudinal direction by the movement of the shaft.

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