JP2020090015A - Liquid storage tank and droplet discharge head - Google Patents

Abstract

To provide a liquid storage tank which enables a liquid to circulate in a droplet discharge head easily and more efficiently, and to provide the droplet discharge head.SOLUTION: A liquid storage tank includes: a first supply passage 22, a liquid storage part 23, and a second supply passage 24 serving as a supply passage which stores a liquid to be supplied to a discharge operation part of a droplet discharge head and allows the liquid to pass therethrough; and a discharge passage 27 which allows the liquid discharged from the discharge operation part to pass therethrough. The discharge passage 27 has inflow ports 26a, 26b respectively connected to ink inflow ports 17a, 17b of the discharge operation part. Discharge passages 27a, 27b respectively connected to the inflow ports 26a, 26b are joined to communicate with a discharge port 28 which discharges the liquid to the outside.SELECTED DRAWING: Figure 4

Description

The present invention relates to a liquid storage tank and a droplet discharge head.

There is a liquid droplet ejection device that ejects liquid droplets of ink such as ink from a nozzle at a desired timing to land at a desired position. In some of the droplet discharge devices, a liquid storage tank for supplying a liquid is attached to a droplet discharge head provided with a nozzle, and necessary ink is supplied from the liquid storage tank.

Some droplet discharge heads have a discharge path for discharging and circulating ink without discharging the ink from the nozzles. It is possible to discharge bubbles mixed with the liquid in the liquid channel or the liquid in which the components have been separated by staying in the liquid channel for a long time through such a discharge path. Further, there is a technique in which a plurality of liquid flow paths are provided in the droplet discharge head to stabilize the liquid temperature and control the liquid flow velocity (Patent Document 1).

Special table 2011-520664 gazette

However, when the liquid channels that are separated and merged are provided in the droplet discharge head, the flow rate varies between the liquid channels depending on the difference in resistance such as the thickness and the length of the liquid channels. Therefore, in the conventional configuration, there is a problem that it takes time and an extra flow rate to circulate an appropriate amount of liquid in each liquid flow path of the droplet discharge head.

An object of the present invention is to provide a liquid storage tank and a droplet discharge head that allow liquid to be circulated in the droplet discharge head easily and more efficiently.

In order to achieve the above object, the invention according to claim 1 is
A supply channel for storing and passing the liquid to be supplied to the discharge operation unit of the droplet discharge head,
A discharge flow path for passing the liquid discharged from the discharge operation unit,
Equipped with
The discharge flow path has an inlet that is connected to each of the plurality of outlets of the discharge operation unit, and discharge tributaries connected to the respective inlets merge to form an outlet that discharges the liquid to the outside. It is a liquid storage tank that is in communication.

The invention according to claim 2 provides the liquid storage tank according to claim 1,
It is characterized in that any one of the discharge tributary channels is provided with an adjusting unit for adjusting a ratio of a flow rate to another discharge tributary channel.

The invention according to claim 3 provides the liquid storage tank according to claim 2,
The adjustment unit is a fitting member that fits into the discharge tributary channel.

The invention according to claim 4 is the liquid storage tank according to claim 2 or 3,
The adjusting section is characterized in that the inner diameter of the discharge tributary channel is narrowed at least at a part.

Further, the invention according to claim 5 is the liquid storage tank according to any one of claims 1 to 4,
It has a screw hole for attaching to the discharge operation part.

The invention according to claim 6 provides the liquid storage tank according to any one of claims 1 to 5,
A check valve is provided in each of the plurality of discharge tributary channels.

The invention according to claim 7 is the liquid storage tank according to any one of claims 1 to 6,
The supply channel is provided with a filter that captures foreign matter contained in the liquid.

Further, the invention according to claim 8 is
A liquid droplet ejection head comprising: the liquid storage tank according to any one of claims 1 to 7; and an ejection operation unit that ejects the liquid.

According to a ninth aspect of the invention, there is provided the droplet discharge head according to the eighth aspect,
The discharge operation unit includes a liquid supply flow passage connected to the supply flow passage, and a plurality of drainage flow passages connected to the discharge flow passage.

According to a tenth aspect of the present invention, in the droplet discharge head according to the ninth aspect,
The liquid sending channel is
A storage chamber that stores the liquid supplied from the liquid storage tank,
An individual flow path for sending the liquid from the storage chamber to a plurality of nozzles,
Have
In the plurality of drainage channels,
A first drainage channel for flowing the liquid out of the storage chamber;
A second drainage flow path for letting out the liquid from the middle of the individual flow path;
Is included.

The invention according to claim 11 provides the droplet discharge head according to claim 10,
Any one of the discharge tributary channels is provided with an adjusting unit that adjusts the ratio of the flow rate to another discharge tributary channel,
The adjusting unit is provided in the discharge tributary flow path connected to the first drainage flow path.

According to the present invention, there is an effect that it is possible to easily and efficiently circulate the liquid in the droplet discharge head.

It is a perspective view showing a droplet discharge head of the present embodiment. It is a cross-sectional perspective view of the inside of the main body of the liquid storage tank as viewed from the bottom side. FIG. 6 is a cross-sectional view illustrating an ink flow path of a droplet discharge head. FIG. 6 is a cross-sectional view illustrating an ink flow path of a droplet discharge head. It is sectional drawing which shows the modification of a discharge path. It is a perspective view showing an example of a narrowing member provided in a discharge way.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a perspective view showing a droplet discharge head 100 of this embodiment.

The droplet discharge head 100 is an inkjet head that is attached to a droplet discharge device, for example, an inkjet recording device to discharge ink. The droplet discharge head 100 includes a discharge operation unit 10, a liquid storage tank 20, and the like.

The ejection operation unit 10 has a nozzle N (see FIGS. 3 and 4), and the bottom surface side (−Z side) is the ejection surface in which the opening of the nozzle N is arranged. The ejection operation unit 10 ejects the liquid supplied from the liquid storage tank 20, here, ink, from the nozzle N. Further, the ejection operation unit 10 can eject the supplied ink, which has not been ejected from the nozzle, to the liquid storage tank 20. The ejection operation unit 10 further includes a configuration and an electric circuit (not shown) that gives pressure fluctuations for ejecting ink from the nozzles.

The liquid storage tank 20 is attached to the side (+Z side) opposite to the nozzle opening side (ejection surface side) of the ejection operation unit 10. The liquid storage tank 20 includes a supply port 21 (inlet) for ink supplied from an external ink tank or the like, and a liquid storage section 23 (liquid storage section: FIG. 3, which stores (stores) the supplied ink (liquid). 4) is provided, an outflow port 25 for allowing the ink to flow from the liquid storage unit 23 into the ejection operation unit 10, an inflow port 26 for the ink ejected from the ejection operation unit 10, and an ejection port. It has a discharge port 28 (outlet) for discharging the discharged ink to the outside.

Inside the liquid storage tank 20, an ink flow path (supply flow path), which is connected from the supply port 21 to the outflow port 25 through the liquid storage unit 23 and allows the ink to be supplied to the ejection operation unit 10 to pass, and from the inflow port 26. An ink flow path (discharge flow path), which is connected to the discharge port 28 and allows ink discharged from the discharge operation unit 10 to pass therethrough, is provided. The outflow port 25 is connected to the ink inflow port 11 of the ejection operation unit 10, and the inflow port 26 is connected to the ink outflow port 17 (outflow port) of the ejection operation unit 10. As a result, in the droplet discharge head 100, the ink flow paths (liquid flow paths) from the supply port 21 to the discharge port 28 of the liquid storage tank 20 are connected. The outflow port 25 and the inflow port 26 are provided on the leg portion protruding from the main body portion 20a. A screw S is inserted into each of the screw holes 251 and 261 provided in these legs (here, for the sake of explanation, only one of the two screw holes at the visible position has the inserted screw S. The liquid storage tank 20 is detachably fixed to the discharge operation unit 10 by being screwed.

The liquid storage tank 20 has a shape that is long in the Y direction and thin in the X direction when viewed from the upper surface side (the side overlooking the supply port 21 and the discharge port 28), that is, here in plan view (viewed from the +Z direction). Is becoming The supply port 21 and the discharge port 28 are separately arranged near both ends in the longitudinal direction (Y direction) of the liquid storage tank 20. Similarly, the outflow port 25 and the inflow port 26 are separately arranged near both ends in the longitudinal direction (Y direction) of the liquid storage tank 20.

Further, the liquid storage tank 20 is provided here upward with the inward normal direction of the ejection surface as the reference direction (+Z direction), but the case where the liquid storage tank 20 is slightly inclined is not excluded. Further, the mounting surface of the liquid storage tank 20, that is, the surface of the discharging operation unit 10 opposite to the discharging surface does not have to be parallel to the discharging surface, and may have irregularities. Hereinafter, the upper part and the upper end mean the highest position (the Z coordinate is the maximum) in the +Z direction. The lower part and the lower end mean the lowest position (minimum Z coordinate) in the +Z direction.

The droplet discharge head 100 is provided in the +Z direction with respect to the image forming surface (ink landing surface) of the droplet discharge device, that is, the discharge surface is often parallel to the XY plane, but this is not the only option. Absent. It may be possible to assume a case where it is provided with a slight inclination (90 degrees or less) in the XZ plane (around the Y axis) and/or in the YZ plane (around the X axis). The positional relationship (vertical relationship) in the vertical direction between the supply port 21 and the discharge port 28 depends on the mounting direction of the droplet discharge head 100.

When rotationally arranged in the XZ plane (around the Y axis), the position of the supply port 21 in the vertical direction is usually the position of the discharge port 28 or less, but the position is not limited to this. Here, it is assumed that the supply port 21 and the discharge port 28 have the same height (that is, the discharge surface is parallel to the horizontal plane and the Z direction is the vertical direction). When the position of the discharge port 28 is provided to be higher than the position of the supply port 21, the bubbles mixed with or remaining in the ink in the ink flow path flow to the discharge port 28 by buoyancy. It will be easier.

FIG. 2 is a cross-sectional perspective view of the inside of the main body 20a of the liquid storage tank 20 as viewed from the bottom side. 3 and 4 are cross-sectional views illustrating the ink flow path of the droplet discharge head 100. FIG. 3 is a cross-sectional view taken along a plane parallel to the YZ plane, and in FIG. 3A, the liquid storage section 23 (downstream side storage section 23b) and the surface including the nozzle N are cut, and FIG. In, the cut is made at the surface including the supply port 21 and the discharge port 28. FIG. 4 is a cross-sectional view taken along a plane parallel to the XZ plane, and FIGS. 4A to 4E are cross-sectional views taken along the cross-section line AA-EE in FIG. 3, respectively.

The liquid containing portion 23 provided in the main body portion 20a of the liquid containing tank 20 for storing ink is divided into an upstream containing portion 23a and a downstream containing portion 23b by a filter 231 provided inside (FIG. 2). 4(b) and 4(c)). The filter 231 captures foreign substances (contaminants) in the ink stored in the downstream storage portion 23b. Here, the filter 231 is provided in a plane parallel to the YZ plane, that is, perpendicular to the horizontal plane, and extends in the longitudinal direction.

The supply port 21 and the upstream accommodation part 23a are connected by a first supply path 22 (FIG. 2, FIG. 3(a), FIG. 3(b), FIG. 4(a)), and are supplied from the outside. Ink flows into the upstream storage portion 23a. The opening end 232 at which the first supply path 22 connects to the upstream accommodation portion 23a is provided below the end of the upstream accommodation portion 23a on the side closer to the supply port 21 in the Y direction (see FIGS. 2 and 3 ( a)). Further, the downstream accommodation portion 23b and the outlet 25 are connected by the second supply passage 24 (FIG. 2, FIG. 3(a), FIG. 3(b), FIG. 4(a), and FIG. 4(c). )), the ink supplied to the ejection operation unit 10 flows out from the downstream storage unit 23b. The opening end 233 where the second supply passage 24 connects to the downstream accommodation portion 23b is provided at the upper part of the end of the downstream accommodation portion 23b on the side closer to the discharge port 28 (discharge passage 27) in the Y direction (FIG. 3(a), FIG. 4(c)).

The open end 232 and the open end 233 are provided at diagonal positions in the liquid storage portion 23 (FIG. 2, FIG. 3A, and FIG. 4C). As a result, the ink that has flowed in from the opening end 232 easily passes through the filter 231 in a wide range of the liquid storage portion 23, and the ink is suppressed from stagnation in the remaining portion. The term “diagonal position” as used herein means that the opening is provided so as to include the diagonal apex, and the opening may be provided on any of the three surfaces forming the apex (these are It may span multiple surfaces of the three).

Here, the supply port 21 and the outflow port 25 are provided on the same side in the Y direction and on the opposite side (here, the +Y side) from the inflow port 26 and the exhaust port 28 (the exhaust path 27). The opening end 233 is provided on the side opposite to the supply port 21 and the outlet 25 in the Y direction (FIGS. 3A and 3B). In addition, the opening end 233 (the connection end to the downstream accommodation portion 23b) has a width of the downstream accommodation portion 23b in the direction (X direction) perpendicular to the Y direction within the XY plane (that is, the plane parallel to the ejection surface). (Fig. 4(c)). The second supply path 24 extends from the opening end 233 above the downstream housing portion 23b (+Z side) in the Y direction and then bends downward to enter the lower side (−Z side) of the first supply path. It is connected to the outflow port 25 (Fig. 3(a), Fig. 3(b), Fig. 4(a)). At this time, the second supply path 24 and the storage chamber 12 are set to have appropriate diameters so as to obtain a flow velocity that can advance bubbles in the ink flowing direction in the downward ink flowing direction against the buoyancy. Be done.

The inflow port 26 and the discharge port 28 are provided on the same side in the Y direction and on the opposite side (here, the −Y side) from the supply port 21 and the outflow port 25. The outlet 28 is connected by a discharge path 27 extending in the Z direction (FIGS. 3(a), 3(b), and 4(e)).

A plurality of inflow ports 26 are provided in accordance with the plurality of ink outflow ports 17a and 17b, and two are provided here (FIG. 4(e)). The ink discharge paths 27a and 27b (discharge branch flow paths) that are respectively connected to the two inflow ports 26a and 26b join together inside the liquid storage tank 20 and communicate with a single discharge port 28. The cross-sectional areas of the discharge paths 27a and 27b can be set as appropriate. Alternatively, as described later, the initial cross-sectional area and shape may be the same.

A check valve 271 is provided in the discharge path 27 between the confluence position of the discharge paths 27a and 27b and the discharge port 28 (FIGS. 3B and 4E), and the ink flows backward from the discharge port 28. Therefore, it is prevented from flowing into the discharge operation unit 10.

The upstream accommodation portion 23a and the discharge passage 27 are connected by a degassing passage 29 (FIG. 3(a), FIG. 3(b), FIG. 4(c), FIG. 4(d)). The deaeration path 29 discharges air (bubbles) from the upstream accommodation section 23a. A filter chamber 29a having a filter 291 is provided in the middle of the deaeration path 29 (FIGS. 3A and 4D). Here, the opening of the degassing passage 29 on the discharge passage 27 side is between the inflow port 26 and the check valve 271. Further, the opening 234 of the deaeration path 29 on the upstream accommodation portion 23a side is provided at the upper end of the upstream accommodation portion 23a and at the end closer to the discharge passage 27 in the Y direction. Thereby, the bubbles easily flow into the degassing passage 29 due to the buoyancy. The filter 231 and the filter 291 may be a continuous chain.

The discharge operation unit 10 is provided with a storage chamber 12 (manifold), which communicates with the ink inlet 11 and the ink outlet 17a (FIG. 3B). The ink supply port 11 and the storage chamber 12 are connected by a common supply flow passage 13, and the storage chamber 12 and the ink flow outlet 17a are connected to a common discharge flow passage 14 (first drainage flow passage). It is connected by. The storage chamber 12 sends ink to the plurality of communicating nozzles N via the plurality of branched individual supply channels 15 (individual channels) (FIG. 4B). The storage chamber 12 is provided parallel to the ejection surface and extending in the Y direction. That is, the storage chamber 12 extends parallel to the longitudinal direction of the liquid storage portion 23. The storage chamber 12, the common supply flow path 13, and the individual supply flow path 15 are included in the liquid supply flow path.

The ink inflow port 11 and the ink outflow port 17a are located on the opposite sides of the storage chamber 12 in the Y direction so as to be connected to the outflow port 25 and the inflow port 26a of the liquid storage tank 20, respectively (FIG. 3B). , FIG. 4(a), FIG. 4(e)). That is, the ink outlet 17a is provided on the opposite side of the liquid containing portion 23 from the outlet 25 in the Y direction, and ink can be discharged from the ejection operation unit 10 separately from the nozzle N.

Further, the individual discharge flow paths 19 are branched between the individual supply flow paths 15 and the nozzles N (before the opening of the nozzle N), and these individual discharge flow paths 19 are respectively the common discharge flow paths 18 (FIG. 4B). The common discharge flow path 18 is bent in the +Z direction at the end on the ink outlet 17 side (−Y side) of the ejection operation unit 10, and the end serves as the ink outlet 17b (FIG. 4(e)). ). The ink outlet 17b is connected to the above-mentioned inlet 26b. The individual discharge flow path 19 and the common discharge flow path 18 are included in the second drainage flow path. The first drainage flow path and the second drainage flow path are included in the drainage flow path of the present embodiment.

The surface of the discharge operation unit 10 opposite to the discharge surface is provided with a screw hole into which the above-described screw S is inserted and received. The liquid storage tank 20 is fixed to the discharge operation unit 10 by inserting and fixing the screw S penetrating the screw holes 251 and 261 of the liquid storage tank 20 into the screw holes.

FIG. 5 is a cross-sectional view showing a modified example of the discharge path 27.
As shown in FIG. 5A, a narrowing member 272 as an adjusting portion is inserted in the discharge passage 27a of the first modification. Since the two drainage flow paths in the discharge operation unit 10 have different lengths and thicknesses, the drainage flow path connected to the drainage flow path with the smaller flow path resistance (the larger pressure loss along the drainage flow path) By partially (at least partially) narrowing the inner diameter of the passage, the difference in the passage resistance (pressure loss) is reduced. Here, the common discharge flow path 18 through which the ink flows through the individual supply flow path 15 and the individual discharge flow path 19, which are thinner than the common discharge flow path 14, has a larger pressure loss than the common discharge flow path 14. Therefore, the narrowing member 272 is provided in the discharge passage 27a connected to the common discharge passage 14. As a result, the ink flow can be adjusted so that the flow rate and the flow rate between the two discharge paths 27a and 27b have an appropriate ratio. The narrowing member 272 once inserted and attached need not necessarily be removable or replaceable.

FIG. 6 is a perspective view showing an example of the narrowing member 272 provided in the discharge passage 27a.
In the example shown in FIG. 6A, the narrowing member 272 has a tubular shape having a hollow penetrating portion Hh, and a connector or the like is provided so that its outer circumference is equal to the inner circumference of the tubular discharge passage 27a. It may be provided. Here, the connectors Hc1 and Hc2 are attached to the upper and lower ends of the tube Hp having a predetermined length and embedded in the discharge passage 27a.
Here, a thin groove Ht is provided on the outer surface of the connector Hc1 on the upper end side (downstream side), and the tube Hp between the connectors Hc1 and Hc2 is provided when the narrowing member 272 is inserted and attached to the discharge passage 27a. The remaining air can be exhausted.

The length and the channel diameter of the narrowing member 272 may be determined according to the difference in pressure loss between the storage chamber 12 and the common discharge channel 18. In practice, appropriate settings may be set in advance depending on the combination of the discharge operation unit 10 and the liquid storage tank 20.

In the example shown in FIG. 6B, the narrowing member 272 is provided with a plurality of grooves Ht2 that surround the annular shape in a direction perpendicular to the penetrating direction of the penetrating portion Hh. Further, the width of the tube Hp2 on the lower end side is narrower than that of the connector Hc3 on the upper end side. By press-fitting the narrowing member 272 from the side of the tube Hp2, the pressure loss due to the ink flow passing through increases due to the flow path resistance of the penetrating portion Hh.

As described above, by inserting the narrowing member 272 as a fitting member separate from the liquid storage tank 20 into the discharge passage 27a and fitting the narrowing member 272, the flow velocity and the flow rate can be easily adjusted without complicating the structure of the liquid storage tank 20. It will be possible. On the other hand, as shown in FIG. 5( b ), the narrowed portion 272 a inside the discharge passage 27 a of Modification 2 is provided integrally with the liquid storage tank 20. Further, as shown in FIG. 5C, a bent portion 272b is provided in the discharge passage 27a of the modified example 3, and the flow velocity and the flow rate are adjusted by the pressure loss due to the extension of the length and the addition of the bend. . In any of these modified examples 1 to 3, the shape is not limited to the illustrated shape, and a shape such that bubbles are less likely to stay in the discharge passage 27a, for example, to the narrowed member 272 or the narrowed portion 272a. The entrance and exit may be tapered, and the bent portion 272b may be bent in a curved shape or the like.

As described above, the liquid storage tank 20 according to the present embodiment stores the ink supplied to the ejection operation unit 10 of the liquid droplet ejection head 100, the supply passage through which the ink is passed, and the liquid discharged from the ejection operation unit 10. And a discharge flow path for passing the discharge flow path. The discharge passage has discharge ports 26a and 26b connected to the plurality of ink outlets 17a and 17b of the discharge operation unit 10, and discharge passages 27a and 27b that are discharge tributary passages connected to the discharge ports 26a and 26b, respectively. Merge and communicate with the discharge port 28 for discharging the ink to the outside.
As described above, when the ejection operation unit 10 has a plurality of ink drainage channels, by using the liquid storage tank 20 that internally has a drainage channel for joining the inks from the plurality of drainage channels, It is not necessary to join the inside of the operation unit 10. As a result, in the ejection operation unit 10, a liquid having an appropriate flow rate and flow velocity can be easily and efficiently flowed to each drainage flow channel (discharge route) without considering the balance between the ink flow rate and the flow velocity in each drainage flow channel. be able to. Therefore, in the droplet discharge head 100 having a plurality of ink flow paths, it becomes possible to easily and efficiently circulate the liquid having an appropriate flow rate. In particular, when the discharge operation unit 10 is cleaned using water or a cleaning liquid as the liquid, by simply disconnecting the liquid storage tank 20 from the discharge operation unit 10, labor can be simplified and efficiency is improved. Further, since the flow rate of each drainage flow path can be adjusted on the side of the liquid storage tank 20 or the liquid storage tank 20 can be simply replaced, the cost and labor required according to the accuracy required for ink ejection can be reduced. It is possible to reduce the cost and the labor as compared with the case where the adjustment is performed by the discharge operation unit 10. On the other hand, since the inks in the plurality of drainage channels are finally merged and discharged, the use of this liquid storage tank 20 does not complicate the piping outside the droplet discharge head 100. ..

Further, one of the discharge passages 27a and 27b (here, the discharge passage 27a) is a constriction that serves as an adjusting unit that adjusts the ratio of the flow rate to the other discharge passage (here, the discharge passage 27b). The member 272, the narrowed portion 272a or the bent portion 272b is provided. Accordingly, when an ink flow is generated such that ink is circulated through the ejection operation unit 10 for maintenance or the like, it is possible to easily balance the ink flow rate and the flow velocity between the plurality of drainage flow paths outside the ejection operation unit 10. Can be adjusted. Therefore, by replacing or adjusting the liquid storage tank 20 without further complicating the designing and manufacturing of the discharge operation unit 10 that requires high precision, it is possible to easily and efficiently circulate the ink in each drainage channel properly. be able to.

The narrowing member 272 is a fitting member that fits into the discharge passage 27a. That is, by inserting and fixing the narrowing member 272, which is a fitting member, that can obtain an appropriate pressure loss according to the combination of the product of the discharge operation unit 10 and the liquid storage tank 20 in the droplet discharge head 100, into the discharge path 27a, It becomes possible to easily and appropriately obtain the flow rate and the flow velocity of the discharge flow channel at the time of cleaning each discharge flow channel and the circulation discharge of the ink by reducing the labor.

Further, the narrowing member 272 and the narrowing portion 272a narrow the inner diameter of the discharge passage 27a at least in part. Therefore, it becomes possible to easily and appropriately adjust the pressure loss with such a simple structure and obtain an appropriate flow rate and flow velocity in each drainage flow path.

Further, the liquid storage tank 20 has a screw hole 261 for attaching to the discharge operation unit 10. By making it easy to attach and detach in this way, the labor for assembling the ejection operation unit 10 and the liquid storage tank 20 after forming them separately does not increase significantly.

Further, a check valve 271 is provided between the position where the plurality of discharge paths 27a and 27b meet and the discharge port 28. As a result, it is possible to prevent the ink from flowing back to the ejection operation unit 10 via the respective discharge passages 27a and 27b to cause a problem or to cause an unintended flow.

In addition, a filter 231 that captures foreign matter contained in the ink is provided in the supply flow path (liquid storage portion 23). This suppresses the inflow of foreign matter into the discharge operation unit 10. Further, it is not necessary to provide a filter on the discharge operation unit 10, and the structure of the discharge operation unit 10 and the flow rate control are not complicated.

The droplet discharge head 100 of the present embodiment includes the liquid storage tank 20 described above and the discharge operation unit 10 that discharges ink. In this droplet discharge head 100, the liquid storage tank 20 and the discharge operation unit 10 are separated from each other, and liquid (including a cleaning liquid such as water) is supplied to each drainage flow channel more easily and efficiently at an appropriate flow rate and flow rate. It becomes possible to do. Therefore, cleaning of the discharge operation unit 10 can be efficiently performed. Further, it is easy to reduce the labor and cost without complicating the design and manufacturing of the ejection operation unit 10.

In addition, the discharge operation unit 10 includes a liquid supply passage (common supply passage 13 and storage chamber 12) connected to the supply passage (particularly, the second supply passage 24) of the liquid storage tank 20, and a discharge passage ( In particular, it has a plurality of drainage channels (first drainage channel and second drainage channel) connected to the drainage channel 27). Therefore, it is possible to easily supply the liquid that flows at an appropriate flow rate and flow rate independently to each of the drainage flow paths of the ejection operation unit 10, and to appropriately control the ejection operation unit 10 without considering the influence between the two. The cleaning can be performed separately from the storage tank 20, and the labor is reduced.

Further, the liquid supply flow path has a storage chamber 12 that stores the ink supplied from the liquid storage tank 20, and an individual supply flow path 15 that sends the ink from the storage chamber 12 to the plurality of nozzles N. The plurality of drainage channels include a first drainage channel (such as the common drainage channel 14) that causes the ink to flow out from the storage chamber 12, and a second drainage channel that causes the ink to flow out in the middle of the individual supply channel 15. Liquid flow paths (individual discharge flow path 19, common discharge flow path 18) are included. By thus having the discharge operation unit 10 having two types of drainage flow paths, the discharge operation unit 10 (droplet discharge head 100) can easily and reliably perform appropriate air discharge, ink circulation, and replacement. Can be done. Then, in such a case, it is not necessary to join the two types of drainage flow paths in the discharge operation unit 10. Therefore, by separating the liquid storage tank 20 when cleaning the ink flow path in the ejection operation unit 10 including these drainage flow paths, the flow rate control becomes easy and the efficiency can be improved. Further, by making it possible to control and set the flow rate of each discharge flow path on the liquid storage tank 20 side, rather than performing designing, manufacturing, or adjustment so as to control within the discharge operation unit 10 of required accuracy and manufacturing cost. Also, it is possible to easily and inexpensively adjust the flow rate of the flow rate between the drainage channels of the entire droplet discharge head 100. On the other hand, since they are merged after each flowing out from the ejection operation unit 10, the piping after ejection from the droplet ejection head 100 is not complicated.

Further, the adjusting portion (stenosis member 272, stenosis portion 272a or bent portion 272b) is provided in the discharge passage 27a connected to the first drainage flow passage. Since the first drainage flow path has a smaller pressure loss than the second drainage flow path that passes through a narrow path having a large pressure loss, such as the individual supply flow path 15 and the individual discharge flow path 19, By increasing the pressure loss of the discharge passage 27a connected to the first drainage passage on the side of the liquid storage tank 20, the flow of ink in the two drainage passages is more easily balanced, and the reliability and efficiency are improved. It is possible to often remove the air bubbles, or to discharge and replace the ink that has passed a long time after being supplied.

It should be noted that the present invention is not limited to the above embodiment, and various modifications can be made.
For example, in the above-described embodiment, the two inlets 26a and 26b and the discharge passages 27a and 27b are described as being provided, but three or more may be provided. For example, when the nozzles N of the ejection operation unit 10 are two-dimensionally arranged, a plurality of common discharge flow paths 18 may be provided and separate ink outlets 17b may be provided. In this case, the merging position of the plurality of discharge tributary channels does not have to be one. The main flow of the discharge flow path, in which at least two discharge sub-flow paths merge, may be merged at a different position in another discharge sub-flow path.

Alternatively, a filter may be provided in the storage chamber 12 of the ejection operation unit 10 and a common discharge flow path 14 may be provided upstream and downstream of the filter to allow ink to flow out from the separate ink outlets 17a.

Further, in the above embodiment, the filter is provided inside the liquid storage portion 23, but the filter may not be provided. In this case, a filter may be provided in the storage chamber 12 of the ejection operation unit 10, or the ink that has passed through the external filter may be supplied to the liquid storage tank 20 without the filter. In these cases, the arrangement of the first supply passage 22 and the second supply passage 24, and the connection position with the liquid storage portion 23 may be adjusted appropriately. Further, the filter may be provided in the supply channel other than the inside of the liquid storage portion 23. When the filter 231 is provided, the direction and size of the filter 231 may be changed as appropriate.

Further, the narrowing member 272, the narrowing portion 272a, and the bent portion 272b serving as the adjusting portion described in the above-described embodiment may have other shapes and structures. A bent portion may be further provided for the flow path inside the narrowing member 272 which is a fitting member.

Further, in the above-described embodiment, the liquid storage tank 20 is detachably fixed to the discharge operation unit 10 by the screw that passes through the screw hole, but other fixing mechanisms may be used or used together. Good.

Further, the structure of the ejection operation unit 10 and the ink (liquid) ejection mechanism are not particularly limited. It is only necessary that the liquid be separately discharged via two or more paths. Further, the degassing passage 29, the check valve 271, and the like are not necessarily required configurations. Further, the check valve 271 may be provided in each of the discharge tributaries.

Further, in the above-described embodiment, the ink is stored in and passed through the liquid storage tank 20, and the ink is ejected by the ejection operation unit 10. However, clear ink or the like is used as the liquid to be stored, passed, or ejected. It may be a transparent liquid, a liquid for forming a structure such as a thin film, or a liquid for providing a protective film.
In addition, specific details such as the configurations, arrangements, and structures shown in the above-described embodiments can be appropriately changed without departing from the spirit of the present invention.

10 Ejection Operation Unit 11 Ink Inlet 12 Storage Chamber 13 Common Supply Flow Path 14 Common Discharge Flow Path 15 Individual Supply Flow Paths 17, 17a, 17b Ink Outlet 18 Common Discharge Flow Path 19 Individual Discharge Flow Path 20 Liquid Storage Tank 20a Main Body Portion 21 Supply port 22 First supply passage 23 Liquid storage portion 23a Upstream storage portion 23b Downstream storage portion 231 Filter 232, 233 Open end 234 Open 24 Second supply passage 25 Outlet 251, 261 Screw hole 26, 26a, 26b Inflow ports 27, 27a, 27b Discharge passage 271 Check valve 272 Constriction member 272a Constriction portion 272b Bent portion 28 Discharge port 29 Degassing passage 29a Filter chamber 291 Filter 100 Droplet ejection head N Nozzle

Claims (11)

A supply channel for storing and passing the liquid to be supplied to the discharge operation unit of the droplet discharge head,
A discharge flow path for passing the liquid discharged from the discharge operation unit,
Equipped with
The discharge flow path has an inlet that is connected to each of the plurality of outlets of the discharge operation unit, and discharge tributaries connected to the respective inlets merge to form an outlet that discharges the liquid to the outside. A liquid storage tank that is in communication. The liquid storage tank according to claim 1, wherein any one of the discharge tributary channels is provided with an adjusting portion that adjusts a ratio of a flow rate to another discharge tributary channel. The liquid storage tank according to claim 2, wherein the adjusting portion is a fitting member that fits into the discharge tributary flow path. The liquid storage tank according to claim 2 or 3, wherein the adjusting portion narrows the inner diameter of the discharge branch passage at least in part. The liquid storage tank according to any one of claims 1 to 4, further comprising a screw hole for attaching to the discharge operation unit. The liquid storage tank according to any one of claims 1 to 5, wherein a check valve is provided in each of the plurality of discharge passages. The liquid storage tank according to claim 1, wherein the supply channel is provided with a filter that captures foreign matter contained in the liquid. A liquid droplet ejection head comprising: the liquid storage tank according to any one of claims 1 to 7; and an ejection operation unit that ejects the liquid. 9. The droplet according to claim 8, wherein the discharge operation unit includes a liquid sending flow path connected to the supply flow path, and a plurality of drainage flow paths connected to the discharge flow path. Discharge head. The liquid sending channel is
A storage chamber that stores the liquid supplied from the liquid storage tank,
An individual flow path for sending the liquid from the storage chamber to a plurality of nozzles,
Have
In the plurality of drainage channels,
A first drainage channel for flowing the liquid out of the storage chamber;
A second drainage flow path for letting out the liquid from the middle of the individual flow path;
The droplet discharge head according to claim 9, wherein: Any one of the discharge tributary channels is provided with an adjusting unit that adjusts the ratio of the flow rate to another discharge tributary channel,
The liquid droplet ejection head according to claim 10, wherein the adjustment unit is provided in the discharge tributary flow path connected to the first drainage flow path.