JP7748618B2 - liquid discharge device - Google Patents

Description

The present invention relates to a liquid ejection device.

Patent Document 1 discloses an ejection unit that integrally comprises a head having nozzles that eject liquid and a cleaning mechanism that includes a wiping member that wipes the nozzle surface of the head. The wiping member moves, via a moving member, between a position facing the nozzle surface and a position retracted from the nozzle surface.

With conventional technology, after wiping the nozzle surface, the cleaning liquid used for wiping flows onto the nozzle surface, and as the cleaning liquid flows onto the nozzle surface, it mixes with any liquid (e.g., ink) remaining in the nozzles or on the nozzle surface, potentially re-contaminating the nozzle surface.

The present invention is a liquid ejection device that has a carriage equipped with a head having a nozzle surface with nozzles that eject liquid in a horizontal direction, a wiping member that wipes the nozzle surface, and a cleaning liquid supply member that supplies cleaning liquid to the wiping member, and that moves the head or the wiping member in a vertical direction and a direction intersecting the horizontal direction to wipe the nozzle surface with the wiping member, wherein the upper surface of the outer periphery of the head is configured so that, in the direction of movement of the head or the wiping member, the vertical position at which wiping by the wiping member ends is lower than the vertical position at which wiping starts, and the carriage is equipped with a movement mechanism that moves the nozzle surface relative to the wiping member in the liquid ejection direction of the nozzles, and liquid is ejected from the nozzles onto an object at a liquid ejection position where the nozzle surface is located downstream of the wiping member in the liquid ejection direction, and the wiping member wipes the nozzle surface at a cleaning position where the nozzle surface is located upstream of the wiping member in the liquid ejection direction .

This invention provides a liquid ejection device that reduces the flow of liquid onto the nozzle surface.

1 is an overall perspective view of a liquid ejection device according to an embodiment of the present invention. FIG. 4 is an overall perspective view of the carriage at the retracted position. FIG. 2 is an overall perspective view of the carriage at a liquid ejection position. FIG. 4 is an explanatory diagram of a head position according to an embodiment of the present invention. FIG. 2 is a front view showing a schematic configuration of the head and the cleaning device and its surroundings according to the first embodiment of the present invention. FIG. 2 is an explanatory diagram of the top surface of the outer periphery of the head according to the embodiment of the present invention. FIG. 10 is an explanatory diagram of a second embodiment of the present invention. FIG. 10 is an explanatory diagram of a third embodiment of the present invention. FIG. 10 is an explanatory diagram of a third embodiment of the present invention. FIG. 10 is an explanatory diagram of a third embodiment of the present invention. FIG. 10 is an explanatory diagram of a fourth embodiment of the present invention. FIG. 10 is an explanatory diagram showing another example of a liquid ejection device according to an embodiment of the present invention. FIG. 10 is an explanatory diagram showing yet another example of a liquid ejection device according to an embodiment of the present invention.

Embodiments of the present invention are described below with reference to the drawings.

Figure 1 is an overall perspective view of a liquid ejection device according to an embodiment of the present invention. The illustrated liquid ejection device is a printing device that forms an image on, for example, the side of a truck body.

The printing device 1000 is installed facing the vehicle body side surface 100, which is shown as an example of an object. The printing device 1000 has an X-axis rail 101, a Y-axis rail 102 that intersects with the X-axis rail 101, and a Z-axis rail 103 that intersects with the X-axis rail 101 and the Y-axis rail 102.

The Y-axis rail 102 holds the X-axis rail 101 so that it can move in the Y direction (positive and negative). The X-axis rail 101 holds the Z-axis rail 103 so that it can move in the X direction (positive and negative). The Z-axis rail 103 holds the carriage 1 so that it can move in the Z direction (positive and negative).

The printing device 1000 includes a first Z-direction drive unit 92 that moves the carriage 1 in the Z direction along the Z-axis rail 103, and an X-direction drive unit 72 that moves the Z-axis rail 103 in the X direction along the X-axis rail 101. The printing device 1000 also includes a Y-direction drive unit 82 that moves the X-axis rail 101 in the Y direction along the Y-axis rail 102. The printing device 1000 also includes a second Z-direction drive unit 93 that moves the head holder 70 in the Z direction relative to the carriage 1.

The printing device 1000 configured as described above ejects liquid (ink in this example) from a head mounted on the head holder 70 while moving the carriage 1 in the X, Y, and Z directions, forming an image on the vehicle body side surface 100. Here, the movement of the carriage 1 and head holder 70 in the Z direction does not necessarily mean that it is parallel to the Z direction; it can also be diagonal movement as long as it includes at least a Z-direction component.

In addition, while the surface shape of the vehicle body side surface 100 is shown as flat in Figure 1, the surface shape of the vehicle body side surface 100 may be a nearly vertical surface, a surface with a large radius of curvature, or a surface with some unevenness. Next, the configuration of the carriage 1 will be described.

Figure 2 is an overall perspective view of the carriage in the printing device shown in Figure 1, showing the carriage 1 in a retracted position on the Z axis.

The carriage 1 includes a head holder 70. The carriage 1 is movable in the Z direction along the Z-axis rail 103 using power from a first Z-direction drive unit 92. The head holder 70 holds the heads 300, and is movable in the Z direction relative to the carriage 1 using power from a second Z-direction drive unit 93 shown in FIG. 1. In this embodiment, the heads 300 are configured such that six heads 300a to 300f are arranged in a stacked configuration on the head holder 70.

Each of the heads 300a to 300f has a nozzle surface 302a with multiple nozzles 302. The type and number of ink colors used by the heads 300a to 300f may be different for each head, or they may all be the same color. For example, if the printing device 1000 is a device that uses a single color, the inks used by the heads 300a to 300f may be the same color. Furthermore, the number of heads making up the head 300 is not limited to six. It may be more or less than six.

As shown in the figure, the heads 300 are fixed to the head holder 70 so that the nozzle surface 302a of each head intersects with the horizontal plane (X-Z plane) and the arrangement direction of the multiple nozzles 302 is inclined with respect to the X-axis. This causes the nozzles 302 to eject ink in the horizontal direction (Z direction).

The carriage 1 also includes a cleaning device 4 that cleans the head 300. The carriage 1 supports a frame 2 that surrounds the periphery of the head holder 70. The frame 2 includes a guide rod 3 that consists of a shaft member extending in the X direction, and the cleaning device 4 is attached to the guide rod 3 so that it can move along the guide rod 3 in the X direction, that is, in a direction that intersects the horizontal direction (Z direction) and vertical direction (Y direction).

The frame 2 contains a drive motor for moving the cleaning device 4 along the guide rod 3, a position sensor for detecting the position of the cleaning device 4 in the X direction (standby position, return position), and other components. The drive motor then transmits power to the power transmission belt 5, and the cleaning device 4, connected to the power transmission belt 5, moves in the positive X direction along the guide rod 3. The cleaning device 4 then cleans the nozzle surface 302a and nozzles 302 of the head 300. When the cleaning device 4 continues to move in the positive X direction and reaches the return position, the direction of movement of the cleaning device 4 switches to the negative X direction, and the cleaning device 4 returns to the standby position.

Figure 3 is an overall perspective view of the carriage in the printing device shown in Figure 1, showing the carriage 1 and head 300 in the liquid ejection position on the Z axis.

The difference from Figure 2 is that the carriage 1 and head holder 70 have moved to the positive side in the Z direction. Like the carriage 1, the head holder 70 can also move in the Z direction between a liquid ejection position (Figure 3) and a retracted position (Figure 2). Note that the Z direction position of the carriage 1 when ejecting ink is not always constant. The Z direction position of the carriage 1 when ejecting ink varies in accordance with the surface shape of the vehicle body side surface 100.

Figure 4 is an explanatory diagram of head positions in an embodiment of the present invention, with Figure 4(a) showing the head in the liquid ejection position, Figure 4(b) showing the head in the cleaning position, and Figure 4(c) showing the head in the retracted position. Note that the following explanation will be simplified, assuming there are four heads (300a to 300d).

The head 300 is connected to a slide mechanism 90 via a head holder 70. The slide mechanism 90 corresponds to the first Z-direction drive unit 92 and second Z-direction drive unit 93 shown in Figure 1, and for convenience, they will be described together here. This slide mechanism 90 enables the head 300 to move to a liquid ejection position, a cleaning position, and a retracted position in the normal direction (Z direction) of the nozzle surface 302a. Here, the slide mechanism 90 is an example of a contact/separation mechanism.

4A, the head 300 protrudes further in the positive Z direction than the cleaning device 4, and ink is ejected from the head 300 while maintaining an appropriate distance between the vehicle body side surface 100 and the head 300 shown in FIG. 1 within an appropriate range, thereby forming an image on the vehicle body side surface 100. By having the head 300 protrude further in the positive Z direction than the cleaning device 4, interference between the vehicle body side surface 100 and the cleaning device 4 during printing is prevented, and an appropriate distance can be maintained between the nozzle surface 302a and the vehicle body side surface 100.

At the cleaning position, as shown in FIG. 4B, the head 300 is retracted further to the negative side in the Z direction than the cleaning device 4, and the wiper 41 contacts the head 300 with an appropriate amount of penetration. At the retracted position, as shown in FIG. 4C, the head 300 is retracted further to the negative side in the Z direction than the cleaning position, and the wiper 41 does not contact the head 300. Note that even in the retracted position, the cleaning device 4 can move in the X direction (positive and negative). Next, the configuration around the head 300 and the cleaning device 4 will be described.

Figure 5 is a front view showing the schematic configuration of the head and cleaning device surrounding the first embodiment of the present invention.

The frame 2 attached to the carriage 1 has guide rods 3 at its top and bottom. The guide rod 3 holds the cleaning device 4 via a bushing member 3a. The top of the cleaning device 4 is connected to a power transmission belt 5 attached above the guide rod 3, and the power from the power transmission belt 5 moves the cleaning device 4 in the X direction (positive and negative) along the guide rod 3.

The cleaning device 4 includes a wiper 41, a cleaning liquid supply member 42, and a cleaning liquid recovery member 43. As the cleaning device 4 moves in the X direction, the wiper 41 wipes the nozzle surface 302a of the head 300 (300a-300d) fixed to the head holder 70, removing dirt from the nozzle surface 302a. Here, the wiper 41 is an example of a wiping member. The cleaning liquid supply member 42 is located above the wiper 41 (positive side in the Y direction) and supplies cleaning liquid from above the wiper 41 downward (negative side in the Y direction). The cleaning liquid recovery member 43 is located below the wiper 41 (negative side in the Y direction) and recovers waste liquid such as excess cleaning liquid. The cleaning liquid supply member 42 and cleaning liquid recovery member 43 are connected by piping to the cleaning liquid supply source and cleaning liquid recovery destination, respectively, so that cleaning liquid is supplied from the cleaning liquid supply source to the cleaning liquid supply member 42, and the waste liquid from the cleaning liquid recovery member 43 is recovered at the cleaning liquid recovery destination.

The outer peripheral upper surfaces 301 of the heads 300a-300d are arranged so that, in the direction of movement of the wiper 41 (X direction), the vertical (Y) position at the end of wiping by the wiper 41 (positive side of the X direction) is lower than the vertical position at the start of wiping (negative side of the X direction).

In the above configuration, when cleaning the nozzle surface 302a, the head 300 and cleaning device 4 are positioned as shown in Figure 4(b), and the wiper 41 wipes the nozzle surface 302a as the cleaning device 4 moves in the positive X direction. Once the wiper 41 has passed the nozzle surface 302a and wiping of the nozzle surface 302a is complete, the head 300 and cleaning device 4 are positioned as shown in Figure 4(c), and the cleaning device 4 is moved in the negative X direction with the wiper 41 no longer in contact with the head 300. This returns the cleaning device 4 to its standby position.

The standby position of the cleaning device 4 may be a state in which the cleaning device 4 is located to the right of the head 300 as shown in FIG. 5, or a state in which the cleaning device 4 is located to the left of the head 300. In the latter case, when moving the cleaning device 4 forward, i.e., toward the negative side of the X direction, the wiper 41 and the head 300 are separated and the cleaning device 4 is moved to the right of the head 300. Then, when moving the cleaning device 4 backward, i.e., toward the positive side of the X direction, the wiper 41 and the head 300 are brought into contact and the cleaning device 4 is moved to the left of the head 300 to wipe the nozzle surface 302a.

When cleaning is performed during either the forward or backward movement of the cleaning device 4, the outer peripheral upper surface 301 of the head 300 is positioned so that the vertical position at the wiping end is lower in the wiping direction than the vertical position at the wiping start. This prevents cleaning liquid overflowing onto the outer peripheral upper surface 301 of the head 300 after wiping from flowing onto the nozzle surface 302a and soiling the nozzle surface 302a.

Furthermore, by performing one-way cleaning either when the cleaning device 4 moves forward or backward, it is possible to reduce the consumption of cleaning fluid. It also reduces the number of times the wiper 41 comes into contact with the nozzle surface 302a, thereby extending the life of the wiper 41. In particular, when printing images with a low print rate or a short printing width, the amount of ink used is small and the amount of ink adhering to the nozzle surface 302a is also small, so the one-way cleaning described above is preferable.

Figure 6 is an explanatory diagram of the top surface of the outer periphery of a head according to an embodiment of the present invention, with Figure 6(a) showing the embodiment of the present invention and Figure 6(b) showing the configuration of a comparative example.

In an embodiment of the present invention, as shown in Figure 6(a), the vertical (Y direction) position of the outer peripheral upper surface 301 of the head 300 at the end of wiping by the wiper 41 (positive X direction) is lower than the vertical position at the start of wiping (negative X direction). As a result, after the wiper 41 wipes the nozzle surface 302a, excess cleaning liquid Lc used in wiping flows over the outer peripheral upper surface 301 of the head, and the cleaning liquid Lc immediately reaches the edge portions (corners) of the head 300. This makes it difficult for the cleaning liquid Lc to flow onto the nozzle surface 302a, reducing the problem of the nozzle surface 302a being wiped by the wiper 41 becoming contaminated again.

In this embodiment, the wiper 41 is made of an elastic material such as sponge or low-hardness rubber, and deforms when it comes into contact with the nozzle surface 302a, wiping away ink stains adhering to the nozzle surface 302a. As a result, excess cleaning liquid Lc overflows from the contact surface between the wiper 41 and the nozzle surface 302a, and then flows in the negative vertical direction (Y direction) along the slope of the outer peripheral upper surface 301.

On the other hand, if the vertical position of the outer peripheral upper surface 301 at the end of wiping by the wiper 41 is higher than the vertical position at the start of wiping, as in the comparative example in Figure 6(b), excess cleaning liquid Lc flows along the outer peripheral upper surface 301 toward the negative side in the X direction.

In this case, the cleaning liquid Lc flows a long distance, and as it flows toward the negative side of the X direction, it overflows onto the nozzle surface 302a. The overflowing cleaning liquid Lc mixes with the ink remaining in the nozzles 302 and nozzle surface 302a as it flows, thereby contaminating the nozzle surface 302a again.

As described above, this embodiment of the invention relates to a printing apparatus 1000 that includes a head 300 having a nozzle surface 302a with nozzles 302 that eject ink in the horizontal direction (Z direction), a wiper 41 that wipes the nozzle surface 302a, and a cleaning liquid supply member 42 that supplies cleaning liquid to the wiper 41. The wiper 41 moves in a direction (X direction) that intersects the vertical direction (Y direction) and the horizontal direction (Z direction) to wipe the nozzle surface 302a with the wiper 41. The vertical position of the outer peripheral upper surface 301 of the head 300 at the end of wiping by the wiper 41 is lower than the vertical position at the start of wiping, in the direction of the wiper 41's movement. This makes it difficult for cleaning liquid used to wipe the nozzle surface 302a to flow back onto the nozzle surface 302a, thereby reducing the risk of the nozzle surface 302a becoming contaminated again after wiping. The "horizontal direction" (Z direction) is not necessarily limited to a direction perpendicular to the direction of gravity. The direction may be slightly off as long as the above effect can be achieved by lowering the position of the wiping end side.

In addition, as described above, a slide mechanism 90 is provided that moves the nozzle surface 302a toward and away from the wiper 41. This makes it possible to move the nozzle surface 302a away from the wiper 41 when moving the wiper 41 in the X direction without wiping the nozzle surface 302a, thereby eliminating the waste of cleaning fluid and unnecessary contact of the wiper 41 with the nozzle surface 302a.

Figure 7 is an explanatory diagram of a second embodiment of the present invention. Note that components equivalent to those described in the above embodiments are given the same reference numerals and will not be described here.

In the embodiment shown in FIG. 5, one-way cleaning is performed either during the forward or backward movement of the cleaning device 4. In contrast, in the second embodiment, the nozzle surface 302a is cleaned back and forth during the reciprocating movement of the cleaning device 4, that is, both during the forward movement of the cleaning device 4 in the negative X direction and during the backward movement of the cleaning device 4 in the positive X direction. When printing images with a high print rate or a long printing width, a large amount of ink is used and a large amount of ink adheres to the nozzle surface 302a, so reciprocating cleaning is preferable.

When the wiper 41 wipes the nozzle surface 302a on the outbound and return paths of reciprocating movement, the outer peripheral upper surface 301 of the head 300 is positioned so that the vertical position on the side where wiping ends on the return path (positive side in the X direction) is lower than the vertical position on the side where wiping begins on the return path (negative side in the X direction). This prevents cleaning liquid mixed with ink from overflowing onto the outer peripheral upper surface 301 of the head 300 after wiping and flowing onto the nozzle surface 302a, thereby contaminating the nozzle surface 302a.

When the wiper 41 is moved from the wiping end side to the wiping start side on the return path, i.e., when it is moved in the wiping direction on the outward path in Figure 7, and wiping does not need to be performed on the outward path, the wiper 41 may be moved away from the nozzle surface 302a by the slide mechanism 90 described above.

As described above, in this embodiment, the wiper 41 is capable of reciprocating movement in the direction of movement of the wiper 41 (X direction), wiping the nozzle surface 302a on both the outbound and return paths of the reciprocating movement, with the wiping end side being the wiping end side on the return path. This makes it less likely that the cleaning liquid used to wipe the nozzle surface 302a will flow onto the nozzle surface 302a, even in the case of reciprocating cleaning, reducing the problem of the nozzle surface 302a becoming soiled again after wiping.

Furthermore, as described above, when the wiper 41 moves back and forth, the slide mechanism 90 separates the wiper 41 from the nozzle surface 302a when the wiper 41 is moved from the end side of the return path to the start side of the return path. This makes it difficult for cleaning liquid to flow onto the nozzle surface 302a even when wiping is performed on one side of the return path, reducing the problem of the nozzle surface 302a becoming soiled again after wiping.

Figure 8 is an explanatory diagram of the third embodiment of the present invention, with Figure 8(a) being a front view showing the general configuration of the head and cleaning device and its surroundings, and Figure 8(b) being a side view thereof. Note that components equivalent to those described in the first and second embodiments are given the same reference numerals and will not be described here.

In the first and second embodiments, the cleaning device 4 is mounted on the carriage 1, but in this embodiment, the cleaning device 4 is not mounted on the carriage 1, but is fixed to the end of the X-axis rail 101 of the printing device 1000.

The carriage 1 is movable in the X direction (positive and negative) along the X-axis rail 101, and holds the head holder 70 via a slide mechanism 90. The head holder 70 is equipped with a head 300, as in the above-described embodiment. The X-axis rail 101 also has a cleaning device 4 fixed to its end. The cleaning device 4 is equipped with a wiper 41, a cleaning liquid supply member 42, and a cleaning liquid recovery member 43, as in the above-described embodiment.

Figure 9 is also an explanatory diagram of the third embodiment, with Figure 9(a) being a top view showing the general configuration of the head and cleaning device, and Figure 9(b) being a front view of the head unit.

When cleaning the nozzle surface 302a in the third embodiment, the carriage 1 is first moved to the right of the cleaning device 4, and then the head 300 and cleaning device 4 are positioned as shown in Figure 8(b). After that, the wiper 41 wipes the nozzle surface 302a as the carriage 1 moves in the positive X direction.

In this embodiment, the outer peripheral upper surface 301 of the head 300 is inclined so that the negative X-direction side is lower, but as long as the vertical position at the end of wiping by the wiper 41 is lower than the vertical position at the start of wiping, the upper surface 301 may also be inclined so that the positive X-direction side is lower, as shown in Figure 10.

When cleaning is performed during either the forward or backward movement of the carriage 1, the outer peripheral upper surface 301 of the head 300 is positioned so that the vertical position at the wiping end is lower in the wiping direction than the vertical position at the wiping start. This prevents cleaning liquid overflowing onto the outer peripheral upper surface 301 of the head 300 after wiping from flowing onto the nozzle surface 302a and soiling the nozzle surface 302a.

Furthermore, by performing one-way cleaning either when the carriage 1 moves forward or backward, it is possible to reduce the consumption of cleaning fluid. It also reduces the number of times the wiper 41 comes into contact with the nozzle surface 302a, thereby extending the life of the wiper 41. In particular, when printing images with a low print rate or a short printing width, the amount of ink used is small and the amount of ink adhering to the nozzle surface 302a is also small, so it is preferable to perform the one-way cleaning described above.

As described above, this embodiment of the invention is a printing apparatus 1000 that includes a head 300 having a nozzle surface 302a with nozzles 302 that eject ink in the horizontal direction (Z direction), a wiper 41 that wipes the nozzle surface 302a, and a cleaning liquid supply member 42 that supplies cleaning liquid to the wiper 41. The head 300 moves in a direction (X direction) that intersects the vertical direction (Y direction) and horizontal direction (Z direction) to wipe the nozzle surface 302a with the wiper 41. The vertical position of the outer peripheral upper surface 301 of the head 300 at the end of wiping by the wiper 41 is lower than the vertical position at the start of wiping in the direction of movement of the head 300. This makes it difficult for cleaning liquid used to wipe the nozzle surface 302a to flow back onto the nozzle surface 302a, reducing the problem of the nozzle surface 302a becoming contaminated again after wiping.

In addition, as described above, a slide mechanism 90 is provided that moves the nozzle surface 302a toward and away from the wiper 41. This makes it possible to move the nozzle surface 302a away from the wiper 41 when moving the head 300 in the X direction without wiping the nozzle surface 302a, thereby eliminating the waste of cleaning fluid and unnecessary contact of the wiper 41 with the nozzle surface 302a.

Figure 11 is an explanatory diagram of the fourth embodiment of the present invention, where Figure 11(a) is a top view showing the general configuration of the head and cleaning device and its surroundings, and Figure 11(b) is a front view of the head unit. Note that components equivalent to those shown in the third embodiment are given the same reference numerals and will not be described here.

In the third embodiment, one-way cleaning is performed either during the forward or backward movement of the carriage 1. In contrast, in the fourth embodiment, reciprocating cleaning of the nozzle surface 302a is performed during the reciprocating movement of the carriage 1, that is, both during the forward movement of the carriage 1 in the negative X direction and during the backward movement of the carriage 1 in the positive X direction. When printing an image with a high print rate or a long printing width, a large amount of ink is used and a large amount of ink adheres to the nozzle surface 302a, so reciprocating cleaning is preferable.

When the wiper 41 wipes the nozzle surface 302a on the outbound and return paths of reciprocating movement, the outer peripheral upper surface 301 of the head 300 is positioned so that the vertical position on the side where wiping ends on the return path (negative side in the X direction) is lower than the vertical position on the side where wiping begins on the return path (positive side in the X direction). This prevents cleaning liquid mixed with ink from overflowing onto the outer peripheral upper surface 301 of the head 300 after wiping and flowing onto the nozzle surface 302a, thereby contaminating the nozzle surface 302a.

Once the carriage 1 moves in the positive X direction and the head 300 passes the cleaning device 4, the head holder 70 moves in the positive Z direction by the slide mechanism 90. Using this slide mechanism 90, it is possible to adjust the position of the nozzle surface 302a relative to the wiper 41, and switch between contact and separation between the wiper 41 and the nozzle surface 302a.

When the carriage 1 is moved in the wiping direction on the outward path (from the wiping end side to the wiping start side on the return path) and wiping does not need to be performed on the outward path, the nozzle surface 302a may be moved away from the wiper 41 by the slide mechanism 90.

As described above, in this embodiment, the head 300 (carriage 1) is capable of reciprocating movement in the direction of movement of the head 300 (X direction), wiping the nozzle surface 302a on both the outbound and return paths of the reciprocating movement, with the wiping end side being the wiping end side on the return path. This makes it difficult for the cleaning liquid used to wipe the nozzle surface 302a to flow onto the nozzle surface 302a, even in the case of reciprocating cleaning, reducing the problem of the nozzle surface 302a becoming soiled again after wiping.

Furthermore, as described above, when the head 300 (carriage 1) moves back and forth, if the head 300 is moved from the side where wiping ends on the return path to the side where wiping begins on the return path, the slide mechanism 90 separates the wiper 41 from the nozzle surface 302a. This makes it difficult for cleaning liquid to flow onto the nozzle surface 302a even when wiping is performed on one side of the return path, reducing the problem of the nozzle surface 302a becoming soiled again after wiping.

Figure 12 is an explanatory diagram showing another example of a liquid ejection device according to an embodiment of the present invention, where Figure 12(a) is an overall configuration diagram and Figure 12(b) is an enlarged view of the main parts of Figure 12(a).

The illustrated liquid ejection device is a printing device that forms an image on, for example, the side of an aircraft fuselage. The printing device 2000 is equipped with a linear rail 404 that supports the carriage 1 so that it can move linearly back and forth, and an articulated robot 405 that moves the linear rail 404 to a predetermined position as needed and holds it in that position. The articulated robot 405 is equipped with a robot arm 405a that has multiple joints that allow it to move freely like a human arm, and the tip of the robot arm 405a can be moved freely and positioned accurately.

The articulated robot 405 may be, for example, a six-axis controlled industrial robot with six axes, i.e., six joints. With a six-axis articulated robot, by teaching information about its operation in advance, the linear rail 404 can be positioned at a predetermined position on the machine body 702 with great accuracy and speed. The robot 405 is not limited to six axes, and articulated robots with an appropriate number of axes, such as five or seven, can also be used.

The robot arm 405a of the robot 405 is equipped with a fork-shaped support member 424. A vertical linear rail 423a is attached to the tip of the left branch 424a of this support member 424, and a vertical linear rail 423b is attached to the tip of the right branch 424b so that they are parallel to each other. The two vertical linear rails 423a, 423b support both ends of the linear rail 404, which movably holds the carriage 1.

The carriage 1 has the configuration of the first to fourth embodiments, and is equipped with a head that ejects liquid toward the body 702. The head may be the head 300 described above, or multiple heads 300 that eject liquid of each color, such as yellow, magenta, cyan, black, and white, or a head 300 with multiple nozzle rows. Liquid of each color is supplied from an ink tank 400 to each head 300 or each nozzle row of the head 300 of this carriage 1.

Carriage 1 moves in a first direction by moving on linear rail 404, and can move in a second direction intersecting the first direction by moving linear rail 404 on vertical linear rails 423a and 423b. Carriage 1 also has a first slide mechanism that moves carriage 1 in a third direction intersecting the first and second directions (in this example, the direction of liquid ejection toward machine body 702). Carriage 1 also has a second slide mechanism that moves the head relative to carriage 1 in the third direction.

The printing device 2000 uses the robot 405 to move the linear rail 404 to the image formation area of the machine body 702, and drives the head 300 while moving the carriage 1 along the linear rail 404 according to the image data to form an image. Then, when printing of one line is completed, the vertical linear rails 423a and 423b are driven to move the head 300 of the carriage 1 from one line to the next. By repeating this operation, it is possible to form an image in the required image formation area of the machine body 702.

Figure 13 is a schematic diagram showing yet another example of a liquid ejection device according to an embodiment of the present invention.

The illustrated liquid ejection device is an unmanned vehicle-type printing device, such as a wall-climbing robot. The printing device 7000 is capable of moving by driving a roller 710 while sucking an object 100 (in this example, the wall of a building) at the bottom of the printing device 7000. The printing device 7000 is equipped with a liquid ejection unit 720 that includes a head that ejects liquid such as ink and a cleaning device, and supplies liquid contained in a liquid tank 730 to the liquid ejection unit 720 via a cable 740. The printing device 7000 then ejects liquid from the head provided in the liquid ejection unit 720 toward the object 100, applying the liquid to the painted area P of the object 100.

In this example, the liquid tank 730 is installed on the ground, and liquid is supplied from the liquid tank 730 to the liquid ejection unit 720 via the cable 740, but the liquid tank 730 may also be provided in the printing device 7000. By providing the liquid tank 730 in the printing device 7000, the movement range restriction imposed by the cable 740 can be eliminated, allowing the printing device 7000 to move freely.

Furthermore, the effects of the present invention can be obtained even when the configuration of the first or second embodiment is applied to the liquid ejection unit 720 of such a printing device 7000.

In the present invention, the liquid may be a solution, suspension, emulsion, or the like containing a solvent such as water or an organic solvent; a colorant such as a dye or pigment; a functionalizing material such as a polymerizable compound, resin, or surfactant; a biocompatible material such as DNA, amino acids, proteins, or calcium; or an edible material such as a natural dye. These can be used, for example, as inkjet ink, paint, surface treatment liquid, a liquid for forming components of electronic elements or light-emitting elements, a liquid for forming electronic circuit resist patterns, a material liquid for three-dimensional modeling, etc.

The above is just one example, and the present invention offers unique advantages in each of the following aspects:

[First aspect]
In a first aspect, a liquid ejection device (e.g., printing device 1000) includes a head (e.g., head 300) having a nozzle surface (e.g., nozzle surface 302a) with nozzles that eject liquid in a horizontal direction (e.g., Z direction), a wiping member (e.g., wiper 41) that wipes the nozzle surface, and a cleaning liquid supply member (e.g., cleaning liquid supply member 42) that supplies cleaning liquid to the wiping member, the head or the wiping member being moved in a vertical direction (e.g., Y direction) and a direction intersecting the horizontal direction (e.g., X direction) to wipe the nozzle surface with the wiping member, wherein the top surface of the outer periphery of the head (e.g., outer periphery top surface 301) is positioned lower in the vertical direction at the end of wiping by the wiping member than at the start of wiping in the direction of movement of the head or the wiping member. According to the first aspect, a liquid ejection device that reduces liquid flow into the nozzle surface can be provided.

[Second aspect]
A second aspect is the first aspect, wherein the head (e.g., head 300) or the wiping member (e.g., wiper 41) is capable of reciprocating movement in the direction of movement of the head or the wiping member (e.g., X direction), the head wipes the nozzle surface (e.g., nozzle surface 302a) on the outward and return paths of the reciprocating movement, and the wiping end side is the wiping end side on the return path. According to the second aspect, even in the case of reciprocating cleaning, cleaning liquid used to wipe the nozzle surface is less likely to flow onto the nozzle surface, thereby reducing the problem of the nozzle surface becoming contaminated again after wiping.

[Third aspect]
The third aspect is characterized in that the first or second aspect further includes a contact/separation mechanism (e.g., slide mechanism 90) that moves the nozzle surface (e.g., nozzle surface 302a) toward and away from the wiping member (e.g., wiper 41). According to the third aspect, when moving the head or the wiping member without wiping the nozzle surface, it is possible to separate the nozzle surface from the wiping member, thereby reducing the consumption of cleaning liquid. Furthermore, since the number of times the wiping member comes into contact with the nozzle surface can be reduced, the life of the wiping member can be extended.

[Fourth aspect]
A fourth aspect is the third aspect, characterized in that, when the head (e.g., head 300) or the wiping member (e.g., wiper 41) is moved from the wiping end side to the wiping start side during the reciprocating movement of the head (e.g., head 300) or the wiping member (e.g., wiper 41), the wiping member and the nozzle surface are separated by the contact/separation mechanism (e.g., slide mechanism 90). According to the fourth aspect, even when wiping is performed on one way of the reciprocating movement, cleaning liquid is less likely to flow into the nozzle surface, and the problem of the nozzle surface becoming soiled again after wiping can be reduced.

REFERENCE SIGNS LIST 1 Carriage 300 Head 301 Peripheral upper surface 302 Nozzle 302a Nozzle surface 4 Cleaning device 41 Wiper 42 Cleaning liquid supply member 43 Cleaning liquid recovery member

Japanese Patent Application Laid-Open No. 2020-168786

Claims (4)

a head having a nozzle surface provided with nozzles that eject liquid in a horizontal direction;
a wiping member that wipes the nozzle surface;
a cleaning liquid supply member that supplies cleaning liquid to the wiping member,
a liquid ejection device in which the head or the wiping member is moved in a vertical direction and a direction intersecting the horizontal direction to wipe the nozzle surface with the wiping member,
an upper surface of the outer periphery of the head is configured such that a vertical position at a wiping end side by the wiping member is lower than a vertical position at a wiping start side in the direction of movement of the head or the wiping member;
the carriage includes a movement mechanism that moves the nozzle surface relative to the wiping member in a liquid ejection direction of the nozzles,
The liquid is discharged from the nozzle to the target object at a liquid discharge position where the nozzle surface is located downstream of the wiping member in the liquid discharge direction;
a wiping member that wipes the nozzle surface at a cleaning position where the nozzle surface is located upstream of the wiping member in the liquid ejection direction ; A liquid ejection device according to claim 1, characterized in that the head or the wiping member is capable of reciprocating movement in the direction of movement of the head or the wiping member, the nozzle surface is wiped on the outward and return paths of the reciprocating movement, and the wiping end side is the wiping end side on the return path. 3. The liquid ejection apparatus according to claim 1 , wherein the movement mechanism is a contact/separation mechanism that moves the nozzle surface toward and away from the wiping member. the movement mechanism is a contact/separation mechanism that moves the nozzle surface toward and away from the wiping member,
A liquid ejection device as described in claim 2, characterized in that when the head or the wiping member is moved from the wiping end side to the wiping start side during the reciprocating movement of the head or the wiping member, the wiping member is separated from the nozzle surface by the contact / separation mechanism.