Patent Application
20210060966
The present application is based on, and claims priority from JP Application Serial Number 2019-156434, filed Aug. 29, 2019, the disclosure of which is hereby incorporated by reference herein in its entirety.
The present disclosure relates to a liquid ejecting apparatus such as a printer.
JP-A-2011-240706 discloses an ink jet printer that performs printing by ejecting a liquid such as ink and the like supplied from a liquid container on a medium such as a sheet of paper and the like through a recording head serving as an example of a liquid ejecting head.
In liquid ejecting apparatuses such as ink jet printers and the like, there are cases in which the liquid ejecting apparatus is conveyed and the like while a liquid such as ink or the like is still contained in the liquid container. While conveying the liquid ejecting apparatus, there are cases in which the liquid ejecting apparatus is disposed at a second posture that is different from a first posture, which is a posture during printing, and that is a posture turned over 90 degrees, for example. When the posture of the printer is changed so that the liquid container is positioned above the liquid ejecting head in the vertical direction, the position of the liquid surface in the liquid container becomes higher than the position of the liquid ejecting head.
While in a state in which the posture has been changed, when the standby position of the liquid ejecting head is a position away from the liquid storage portion in the scanning direction, the distance between the liquid storage portion and the liquid ejecting head becomes large, and the water load in the nozzles of the liquid ejecting head becomes extremely large. In such a case, there have been incidents such as the ink continuously leaking through the nozzles of the liquid ejecting head.
A liquid ejecting apparatus that overcomes the above issue is a liquid ejecting apparatus that includes a liquid ejecting head that ejects a liquid, a liquid storage portion that stores the liquid, a supply flow path that communicates the liquid ejecting head and the liquid storage portion with each other, and an air chamber that is coupled to the supply flow path through a plurality of flow paths. In the liquid ejecting apparatus, the supply flow path includes a filter, the plurality of flow paths are, in the supply flow path, connected upstream from the filter, and the air chamber is positioned at a position higher than the filter when in a first posture that is a posture during use.
Hereinafter, an exemplary embodiment of a liquid ejecting apparatus will be described with reference to the drawings. Note that the liquid ejecting apparatus of the present exemplary embodiment is an ink jet printer that prints (records) characters, images, and the like on a medium by ejecting ink, serving as an example of a liquid, on the medium such as a sheet of paper.
Outline of Liquid Ejecting Apparatus
As illustrated in
In
An operation panel 17 that includes an operation portion 15 including buttons that are operated to give various instructions to the multifunction machine 11, and a display portion 16 that displays information of the liquid ejecting apparatus 12 and the image reading apparatus 13 is provided on the front surface side of the liquid ejecting apparatus 12. Medium accommodation portions 14 in which the mediums are accommodated are mounted below the operation panel 17 in a detachable manner.
Furthermore, a holding portion 19 that holds, in the present exemplary embodiment, four ink tanks 45 (see
As illustrated in
As illustrated in
A transport path FP that has a width that is wider than a width of a medium having the largest width extends in the depth direction Y at a middle portion of the liquid ejecting apparatus 12 in the width direction X. The medium supplied from the medium accommodation portion 14 with a transport portion (not shown) is transported along the transport path FP in a transport direction extending from the rear side towards the front side of the liquid ejecting apparatus 12. The carriage 33 positioned at the home position HP and the ink tanks 45 are positioned at opposite sides that interpose the transport path FP in the width direction X.
As illustrated in
The liquid storage portions 18 include the filling ports 24 through which the liquids can be filled into the storage chambers 23. Each liquid storage portion 18 is formed of a transparent or translucent resin; accordingly, a level of a liquid surface L1 of the liquid stored in each storage chamber 23 can be visually recognized from the outside.
In the liquid storage portions 18, areas of the housing 20 that correspond to the window portions 21 function as visually recognizing surfaces 26 through which the ink inside the storage chambers 23 can be visually recognized. A lower limit scale 27 that indicates the recommended time to refill the liquid to the storage chamber 23, and an upper limit scale 28 that indicates the recommended upper limit of the liquid that can be stored in the storage chamber 23 are provided on the visually recognizing surface 26. Note that the visually recognizing surfaces 26 are provided so as to extend in the vertical direction Z when the liquid ejecting apparatus 12 is at the first posture A.
The liquid ejecting apparatus 12 includes the liquid ejecting head 32 configured to eject the liquids. The liquid ejecting head 32 is held by the carriage 33 configured to reciprocate in a scanning direction (the width direction X). The liquid ejecting head 32 includes a plurality of nozzles 31 open in a nozzle formation surface 30 that is a surface that opposes the medium transported through the transport path FP (see
As illustrated in
As illustrated in
As illustrated in
In the second posture B in which the housing 20 is turned over 90 degrees, the water head difference between the liquid surfaces in the ink tanks 45 positioned above and the openings of the nozzles 31 positioned below becomes large; however, by forming gas-liquid interfaces between the liquids and the air and forming a plurality of meniscuses in the gas-liquid interfaces, the liquid leakage suppressing mechanism LS using the surface tension of the meniscuses suppresses water loads acting on the nozzles 31.
The liquid leakage suppressing mechanism LS of the present exemplary embodiment uses filters 112 that remove foreign matters in the liquids. The filters 112 include a plurality of capillary tubes formed of a plurality of pores. The liquid leakage suppressing mechanism LS generates a bubble point pressure, which is a pressure in the direction opposite the water load, by forming the gas-liquid interfaces in the filters 112 and with surface tension of the plurality of meniscuses formed in the plurality of capillary tubes. The bubble point pressure is measured as a pressure needed when, by applying pneumatic pressure from one surface side of the filter in the liquid and by pushing out, with pneumatic pressure, the liquid inside the capillary tubes formed by the pores of the filter, bubbles are created from the opposite surface of the filter. The pressure needed to push out the liquid forming the meniscuses in the capillary tubes of the filters is considerably large compared with the pressure needed for the liquid to pass through the filters in the liquid. When the liquid ejecting apparatus 12 is in the second posture B, the liquid leakage suppressing mechanism LS forms meniscuses in the capillary tubes formed by the plurality of pores in the filters 112, and suppresses the liquid leakage from the nozzles 31 by reducing the water loads on the openings of the nozzles 31 by using the pressure created by the surface tension of the meniscuses.
As illustrated in
When γ is an interfacial tension of the liquid, θ is a contact angle of the liquid 46, D is a pore diameter of the pore 113 in the filter 112, and r is a pore radius, the component of force (γ×cosq) of the advancing-direction component of the interfacial tension of the liquid 46 acts on the entire circumference (2×π×r) of the inner wall of the circular tube where the meniscus is formed, and the acting force is (γ×cosq×π×D). When the above is divided by the area (π×D2/4) of the pore 113, a pressure P (=4×γ×cosq/D) generated by the capillary force that acts on the meniscus can be obtained.
Generally, the wettability of the ink that is used against the filter 112 is determined; accordingly, in order to increase the capillary force, a filter 112 formed of a material in which the sectional area of the capillary tube formed by the pore 113 is small and in which the contact angle against the ink is large is selected. As described above, by designing a flow path having the filter 112 installed therein, the bubble point pressure can be increased. Since moving of the ink through the filter 112 can be eliminated by setting the bubble point pressure to be larger than the water load, leaking of the ink from the nozzles 31 of the liquid ejecting head 32 can be prevented even when in the second posture B (see
For example, a meshed body, a porous body, a perforated plate in which minute through holes are formed, and the like can be used as the filter 112. A filter of a meshed body includes wire netting, a resin net, a mesh filter, and metal fiber. A filter of metal fiber includes a felt filter, which is a stainless steel fine wire formed in a felt-like manner, and a metallic sintered filter, which is a stainless steel fine wire that has been compressed and sintered. A filter of a perforated plate includes an electroforming metal filter, an electron beam processing metal filter, and a laser beam machining metal filter. A mesh filter is a filter formed by weaving wire, and includes a plain-woven, a twill-woven, a plain dutch weave, and a twilled dutch weave filters.
In particular, in order to not have the foreign matter in the liquid reach the nozzles 31, the nominal filtration rating of the filter 112 is preferably set to about 15 μm that is smaller than a diameter (20 μm, for example) of each opening portion of the nozzle 31.
In such a case, when the liquid is ink (the surface tension being about 28 mN/m, for example), the bubble point pressure, which is a pressure at which the meniscus formed in the hole in the filter 112 brakes, is from about 3 kPa to about 5 kPa. Furthermore, when the twilled dutch weave filter (the nominal filtration rating being 5 μm) is adopted, the bubble point pressure is from about 10 kPa to about 15 kPa.
In the present exemplary embodiment, liquid surfaces in filter chambers 111 in the second posture B are set to be at a height that allows the meniscuses to be formed, as illustrated in
As illustrated in
While four ink tanks 45 are provided in the present exemplary embodiment, for the sake of simplifying the drawing, a single ink tank 45 is illustrated in
In the ink tank 45, the near side with respect to the sheet surface of
As illustrated in
As illustrated in
The supply flow path 51 that communicates the liquid storage portion 18 and the liquid ejecting head 32 with each other includes, midway thereof, a filter 112. In the present exemplary embodiment, the liquid flowing from upstream to downstream is made to pass through the filter 112 by including the filter chamber 111 midway of the supply flow path 51 and providing the filter 112 inside the filter chamber 111. Accordingly, foreign matters present in the liquid upstream of the filter 112 is removed by the filter 112 and incidents such as the foreign matters flowing to the nozzles 31 can be reduced in the flow path between a liquid outlet portion 62 of the liquid storage portion 18 to the nozzles 31 of the liquid ejecting head 32. In the supply flow path 51, a flow path from the liquid outlet portion 62 to upstream coupling portions 63 of the filter chamber 111 is referred to as an upstream supply path 61, and a flow path from a downstream coupling portion 122 of the filter chamber 111 to the sub tank 37 is referred to as a downstream supply path 121.
As illustrated in
As illustrated in
As illustrated in
Since each of the first flow path 71 and the second flow path 101 couples the filter chamber 111 and the air chamber 81 to each other, at least a portion of the liquid positioned above the filter 112, influenced by gravity, moves into the second flow path 101. A volume of air that is the same as the volume of the liquid that has been moved moves from the air chamber 81 to the filter chamber 111 through the first flow path. The air that has been stored in the air chamber 81 gradually moves to the filter chamber 111 in the above manner. A configuration in which the air flows into a portion above the filter 112 is obtained by having the air stored in the air chamber 81 move to the filter chamber 111.
As illustrated in
Flow Path from Ink Tank to Filter Chamber
The upstream supply path 61 that is a flow path from the liquid outlet portion 62 of the liquid storage portion 18 to the upstream coupling portions 63 of the filter chamber 111 will be described first.
As illustrated in
Furthermore, the lower flow path 66 extends further downwards in
As illustrated in
Furthermore, as illustrated in
As illustrated in
As illustrated in
Flow Path from Filter Chamber to Air Chamber
Referring next to
As illustrated in
As illustrated in
As illustrated in
As illustrated in
As illustrated in
As illustrated in
As illustrated in
As illustrated in
As illustrated in
As illustrated in
As illustrated in
Flow Path from Filter Chamber to Liquid Ejecting Head
Lastly, the downstream supply path 121, which is a flow path from the downstream coupling portion 122 of the filter chamber 111 to the liquid ejecting head 32, will be described.
As illustrated in
As illustrated in
Functions of the liquid ejecting apparatus 12 will be described next.
As illustrated in
Before the user starts using the liquid ejecting apparatus 12, the storage chambers 23 of the liquid storage portions 18 in the ink tanks 45 (see
As illustrated in
As illustrated in
As illustrated in
However, since there are two supply paths, an unintended movement of ink may occur at times such as when the apparatus is turned over and when vibration is generated. Accordingly, the lower communication hole 67 that has a small flow path diameter is provided midway of the lower flow path 66 to increase the flow resistance of the ink.
Once the filter chamber 111 is filled with ink, the ink moves to the filter chamber 111 through the upper flow path 65 and the lower flow path 66.
As illustrated in
As illustrated in
As illustrated in
As illustrated in
When in the first posture A (see
As illustrated in
As illustrated in
As illustrated in
As illustrated in
As illustrated in
As illustrated in
As illustrated in
As illustrated in
As illustrated in
As illustrated in
As illustrated in
As illustrated in
As illustrated in
As described above, when the liquid ejecting apparatus 12 is changed from the first posture A (see
The following effects can be obtained with the exemplary embodiment described above in detail.
(1) When the posture of the liquid ejecting apparatus 12 is changed from the first posture A to the second posture B, the liquid in each first filter chamber 115 that has been at a position above the corresponding filter 112 moves, due to the influence of gravity, through the corresponding second flow path 101, positioned below, to the corresponding air chamber 81 through the corresponding second flow path input port 102. A volume of air that is the same as the volume of the liquid that has been moved enters, through the first flow path output port 73, the first filter chamber 115 from the first flow path 71, and the surface of the filter 112 is covered with air. In other words, the liquid surface of the ink in the filter chamber 111 is flush with the upper surface of the filter 112 or is lower than the upper surface of the filter 112. There are capillary tubes formed of the plurality of pores 113 in each filter 112. When the surface of the filter 112 is covered by air, the surface tension of the ink forms meniscuses of the ink in the capillary tubes formed by the pores 113, which generates a bubble point pressure that counters the water load. Since each filter 112 is set so that the bubble point pressure is larger than the water load, the substantial water load acting on the nozzle 31 is suppressed to a small load considering the water head difference between the liquid surface L1 of the liquid storage portion 18 and the nozzles 31. Accordingly, even in the second posture B in which the water head difference between the liquid storage portion 18 and the nozzles 31 becomes large, leaking of the ink from the nozzles 31 of the liquid ejecting head 32 can be prevented.
(2) When in the first posture A, the first flow path 71 and the second flow path 101 that communicate the air chamber 81 and the filter chamber 111 with each other are coupled to the filter chamber 111 at a position that is higher than that of the filter 112. Accordingly, in the first posture A that is a use state of the liquid ejecting apparatus 12, storing of air in the air chamber 81 is facilitated. By having the air stored in the air chamber 81 at all times, the surface of the filter 112 can be covered by air when in the second posture B; accordingly, leaking of the ink from the nozzles 31 of the liquid ejecting head 32 can be prevented in a stable manner. Furthermore, when in the first posture A, the ink does not accumulate in the plurality of flow paths 71 and 101. For example, if the plurality of flow paths 71 and 101 are configured to accumulate the ink in a portion thereof when in the first posture A, old ink such as, for example, sediment of a pigment that has accumulated in a portion of the plurality of flow paths 71 and 101 may become mixed when returned to the first posture A from the second posture B. However, the plurality of flow paths 71 and 101 are configured so that the ink does not easily accumulate in a portion thereof when in the first posture A; accordingly, the above issue can be avoided.
(3) When the liquid ejecting apparatus 12 is, from the first posture A, turned over and changed to the second posture B, influenced by gravity, the ink in the first filter chamber 115 situated upstream of the filter 112 passes through the second flow path 101 positioned below and moves to the air chamber 81 through the second flow path input port 102. Furthermore, since at least a portion of the air chamber 81 is positioned at a position that is lower than that of the filter 112, compared with a configuration in which all of the air chamber 81 is positioned at a position that is higher than that of the filter 112, the amount of ink that moves to the air chamber 81 is increased further. Furthermore, the present exemplary embodiment is configured so that the sum of the volumetric capacity of a portion of the air chamber 81 positioned below the filter 112 and the volumetric capacity of a portion of the second flow path 101 positioned below the filter 112 is larger than the volumetric capacity of a portion of the filter chamber 111 upstream the filter 112. Accordingly, as long as the liquid ejecting apparatus 12 is positioned in the second posture B, the liquid surface in the filter chamber 111 does not exceed above the height of the filter 112 and a state in which the air stored in the air chamber 81 covers the surface of the filter 112 is maintained.
(4) When in the second posture B, after the ink influenced by gravity flows to the ditch portion 75 configured at a height that is a step lower, the ink on the upstream surface of the filter 112 moves to the air chamber 81 through the first flow path input port 72 and the second flow path input port 102; accordingly, no ink remains on the upstream surface of the filter 112, the surface is covered by air, and meniscuses are formed. Accordingly, when the posture of the liquid ejecting apparatus 12 is changed from the first posture A to the second posture B, leaking of the liquid through the nozzles 31 of the liquid ejecting head 32 can be prevented.
(5) Bubbling of the liquid in the air chamber 81 can be suppressed by disposing the division wall 88 at a position that, when in the second posture B, horizontally divides the air chamber 81 into the first air chamber 82 and second air chamber 86 and by hitting the liquid, which tries to move in the air chamber 81 when the liquid ejecting apparatus 12 in the second posture B is vibrated when being conveyed and the like, against the division wall 88 functioning as a barrier. For example, when the volume of the liquid inside the air chamber 81 is increased by bubbling, the substantial amount of liquid accumulated in the air chamber 81 becomes relatively small; accordingly, the liquid surface, which is an interface between the layer of air and the liquid between the liquid storage portion 18 and the filter 112 rises over the anticipated liquid surface height. In such a case, no meniscuses will be formed in the filter 112, and there is a concern that an inconvenience such as a small amount of liquid leaking from the liquid ejecting head 32 may occur until the meniscuses are formed. However, since bubbling in the air chamber 81 can be suppressed, the above inconvenience can be prevented to the utmost. Furthermore, bubbly liquid can be suppressed from entering the second flow path 101, which is a flow path coupled to the filter chamber 111.
(6) Since the division wall 88 is disposed at a position that is higher than that of the liquid surface in the air chamber 81 when in the second posture B, a concern that the liquid that has moved to the air chamber 81 below the division wall 88 will return to the filter chamber 111 is small, and the volume at which the liquid covers the upper surface of the filter 112 can be suppressed.
Note that when in the second posture, by having the volumetric capacity of the second air chamber 86 that is below the division wall 88 and that is at a position lower than the position of the filter 112 be larger than the volumetric capacity of the first filter chamber 115, the entire liquid in the first filter chamber 115 can be moved to the second air chamber 86. Accordingly, there are fewer incidents such as the liquid that has moved to the second air chamber 86 returning to the filter chamber 111, and the liquid can be suppressed from covering the upper surface of the filter 112 once again.
(7) When in the second posture B, most of the ink from the first filter chamber 115 passes through the second flow path 101 and reaches the second air chamber 86. While it is a small amount, the ink that has moved through the first flow path 71 also moves to the second air chamber 86, which is below the division wall 88, by passing through two through holes, namely, the first through hole 84 and the second through hole 85. In other words, when in the second posture B, the ink can be collected to the lower second air chamber 86.
(8) By partitioning the first air chamber 82 and the second air chamber 86 into a plurality of small rooms with the wall portions 83, the wave in the ink, which is generated when the liquid ejecting apparatus 12 is vibrated by being conveyed and the like, is suppressed by having the wave in the ink hit the wall portion 83. With the above, since a large wave is not generated in the ink inside the air chamber 81, bubbling of the ink is suppressed. Accordingly, the frequency of the meniscuses not being formed due to the liquid surface in the filter chamber 111 rising, which is caused by bubbling of the ink inside the air chamber 81, can be reduced and the amount of ink that leaks from the liquid ejecting head 32 until the meniscuses are formed can be suppressed to a small amount. Furthermore, the bubbly ink can be prevented from entering the second flow path 101, which is a flow path coupled to the filter chamber 111.
Furthermore, when the volume of the ink is increased by bubbling, a case in which the bubbly ink moving over the division wall 88 flowing into the first air chamber 82 can be conceived. In such a case as well, due to the function of the wall portion 83, the bubbly ink can be prevented from entering the first flow path 71, which is a flow path coupled to the filter chamber 111.
(9) When the liquid ejecting apparatus 12 is in the second posture B, since the protruded portion 68 in the portion of the supply flow path 51 communicating the liquid storage portion 18 and the filter 112 with each other passes through a position that is lower than the filter, the air upstream of the filter 112 does not easily flow out towards the ink tank 45 side through the upstream supply path 61.
Note that the exemplary embodiment described above can be modified into the following configurations. Furthermore, the exemplary embodiment described above and a modification described below can be appropriately combined as an additional modification, and the modifications described below can be appropriately combined as an additional modification.
While the filter 112 is provided inside the filter chamber 111, the filter 112 may be provided not in the filter chamber 111 but midway of the supply flow path 51.
While the filter 112 is provided in the filter chamber 111 of the ink tank 45, the liquid leakage suppressing mechanism LS including the filter 112 may be provided outside the ink tank 45. Since it is only sufficient that the liquid leakage suppressing mechanism LS generates a bubble point pressure to the extent to which the movement of the ink caused by the water load does not occur, the liquid leakage suppressing mechanism LS does not necessarily have to be mounted in the ink tank 45 positioned farthest away from the carriage 33.
A plurality of filters 112 may be provided midway of each supply flow path 51 of the corresponding ink tank 45.
The liquid leakage suppressing mechanism LS that includes the filter 112 may be provided at a plurality of portions that are midway of each supply flow path 51 of the corresponding ink tank 45. In each of the liquid leakage suppressing mechanisms LS, a plurality of flow paths may be included upstream of the filter 112, and the plurality of flow paths may each be coupled to a different air chamber 81, or when a plurality of supply flow paths extend from the same ink tank, the number of air chambers 81 that is coupled to the plurality of flow paths each coupled to a corresponding one of the plurality of supply flow paths may be one.
When in the first posture A, a portion of the air chamber 81 may be at a position above the filter 112. It is only sufficient that air is stored in the air chamber 81.
The number of flow paths that couple the air chamber 81 and the supply flow path 51 to each other is not limited to two and can be three or more.
While each ink tank 45 is configured as a single component in which the liquid storage portion 18, which is an ink storage portion of the tank, the air chamber 81, the filter chamber 111, and the plurality of flow paths are integrally molded, the ink tank 45 may be configured of different components coupled to each other.
The storage chamber 23 that stores the liquid, and an atmosphere communication portion that communicates the inside of the storage chamber 23 and the atmospheric air with each other may be provided in the liquid storage portion 18.
When in the first posture A, at least one of the plurality of flow paths that couple the air chamber 81 and the filter chamber 111 to each other is coupled to the supply flow path 51 at a position that is lower than the filter 112 or at a height position that is the same as that of the filter 112.
When in the first posture A, the ink tanks 45 are provided at one end portion in the housing 20 of the liquid ejecting apparatus 12 in the width direction X, and the home position HP, which is the standby position of the carriage 33, is provided at the other end portion in the housing 20; however, the home position HP may be provided on the left side in the housing 20 in
When in the second posture B, not all of the ditch portion 75 formed in the wall surface of the first filter chamber 115 needs to be configured a step lower than the height of the upstream surface of the filter 112. It is only sufficient that a portion is configured lower. It is only sufficient that there is one flow path into which the ink that has flowed from the surface of the filter 112 flows and to which the first flow path 71 or the second flow path 101 is coupled, and that there is one portion in the flow path that has a difference in height with the surface of the filter 112. Furthermore, the ditch portion 75 does not have to be lower but can be at the same height as that of the surface of the filter 112. However, when the ditch portion 75 is at the same height with the surroundings or when the height difference is small, depending on the angle of inclination or the posture of the liquid ejecting apparatus 12, there are cases in which the function of the ditch portion 75 cannot be exerted; accordingly, it is desirable that, when in the second posture B, the ditch portion 75 is at a position that is lower than the upstream surface of the filter 112.
The first flow path 71 or the second flow path 101, which are plurality of flow paths, does not have to be directly coupled to the ditch portion 75 around the filter 112, and may be coupled to the ditch portion 75 through another flow path. Coupled to the ditch portion 75 includes coupling to the ditch portion 75 through another flow path. In the present exemplary embodiment, the second flow path 101 passes through the second flow path output port 104 that in a step higher than the ditch portion 75.
In a case in which the filter chamber 111 is not provided in the supply flow path 51, the volumetric capacity of the portion of the air chamber 81 positioned below the filter 112 when in the second posture B, and the volumetric capacity of a portion of the second flow path 101 positioned below the filter 112 when in the second posture B are added. The portion in which the volumetric capacities are added is configured to be larger than the volumetric capacity of the portion positioned above the upper surface of the filter 112 when in the second posture B. In such a case, as long as the liquid ejecting apparatus 12 is positioned in the second posture B, the liquid surface does not exceed above the height of the upper surface of the filter 112 and a state in which the air stored in the air chamber 81 covers the surface of the filter 112 is maintained.
When in the second posture, the sum of the volumetric capacity of the air chamber 81 positioned below the filter 112 and the volumetric capacity of the second flow path 101 positioned below the filter 112 does not have to be larger than the volumetric capacity of a portion of the filter chamber 111 upstream the filter 112. When in the second posture B, the amount of liquid remaining in the filter chamber 111 is large, and when the liquid surface in the filter chamber 111 exceeds the height of the filter 112, the ink leaks from the nozzles 31 of the liquid ejecting head 32 due to the water load. However, after the amount of ink that leaks from the nozzles 31 has moved and from when meniscuses are formed in the upper surface of the filter 112 due to gradual ceasing of the liquid from the upper surface of the filter 112, leading of the ink from the nozzle 31 of the liquid ejecting head 32 can be prevented.
As long as at least a portion of the flow path coupling the air chamber 81 and the filter chamber 111 to each other is connected upstream of the filter 112, in the second posture B, at least one of the plurality of flow paths coupling the air chamber 81 and the filter chamber 111 to each other may be coupled to the supply flow path 51 at a position that is higher than the filter 112. However, as in the present exemplary embodiment, when connected to the supply flow path 51 at a position that is lower than the filter 112, due to the height difference, the ink on the surface of the filter 112 flows and the liquid on the surface of the filter 112 gradually ceases; accordingly, meniscuses are more easily formed between the upper surface and the under surface of the filter 112.
The upper flow path 65 coupling the liquid storage portion 18 and the filter chamber 111 to each other and the second flow path 101 coupling the air chamber 81 and the filter chamber 111 to each other may be separately provided.
While the air chamber 81 is divided into two rooms with the division wall 88, the air chamber 81 may be divided into three or more rooms.
While the division wall 88 of the air chamber 81 is configured to be horizontal when in the second posture B, the division wall 88 may not be horizontal but may be at an angle against a horizontal plane. However, as the angle becomes larger, the effect of preventing wave formation and bubbling becomes smaller.
While two T-shaped wall portions 83 are provided in each of the first air chamber 82 and the second air chamber 86, which are formed by dividing the air chamber 81 with the division wall 88, the number of wall portions and the shape of the wall portions are not limited to any number and shape. It is only sufficient that, in order for the ink and air to move, the wall portions 83 are not close to each other and are not crowded by each other, and there are gaps between the wall portion 83 and the wall portion 83 to the extent that allows the ink and the air to move.
Each wall portion 83 of the air chamber 81 may be configured of a member that is different from those of the wall surfaces of the air chamber 81 and the division wall 88.
While the first air chamber 82 and the second air chamber 86 communicate with each other through two through holes, namely, the first through hole 84 and the second through hole 85, the number of through holes and the shape of the through holes are not limited to the above number and shape. It is only sufficient that the size of each through hole is one that allows the ink and the air to move therethrough.
The entire portion of the supply flow path 51 from the liquid storage portion 18 to the filter 112 may pass through a position that is lower than the filter 112 when in the second posture B.
While the flow-path cross-sectional area (the size) of the lower communication hole 67 takes, for example, a value from 1/20 to ½ of the minimum flow-path sectional area of the lower flow path 66, the shape and the size is not limited to the above. However, since there is a size appropriate for both initial filling of the ink and suppressing unintended movement of the ink, it is desirable that the size be set to the appropriate size that can achieve both of the above.
After performing test printing during pre-shipment inspection of the liquid ejecting apparatus 12, the liquid ejecting apparatus 12 is shipped from the factory after the ink in the entire liquid ejecting apparatus 12 has been emptied, and the user fills the ink into the ink tanks 45 when using the liquid ejecting apparatus 12 for the first time. When the liquid ejecting apparatus 12 is set to the second posture B during transporting and conveying the liquid ejecting apparatus 12, the ink does not leak from the nozzles 31; accordingly, the step of emptying all of the ink that has been filled in the liquid ejecting apparatus 12 during pre-shipment inspection can be omitted and the liquid ejecting apparatus 12 may be shipped out from the factory.
The liquid ejecting apparatus 12 may be a liquid ejecting apparatus 12 that ejects a liquid other than ink. The state of the liquid ejected as minute amounts of droplets from the liquid ejecting apparatus 12 includes a granular shape, a tear shape, or a shape with a threadlike trail. Furthermore, liquid used herein refers to any material that can be ejected by the liquid ejecting apparatus 12. For example, any material in a liquid state is sufficient and the liquid may include a fluid body, such as a liquid body with high or low viscosity, sol, gel water, and other inorganic solvents, an organic solvent, a solution, liquid resin, liquid metal, and metallic melt. Not just liquid as a state of matter, the liquid includes particles of a functional material including a solid body such as a pigment or metal particle that is dissolved, dispersed, or mixed in a solvent. A representative example of the liquid includes ink, liquid crystal, and others that have been described in the exemplary embodiment described above. Note that ink includes a variety of liquid compositions such as a general aqueous ink, solvent ink, and gel ink, and hot melt ink. Examples of the liquid ejecting apparatus may include, for example, a liquid ejecting apparatus that ejects liquid that includes therein, in a dispersed or dissolved manner, a material such as an electrode material or a color material that is used to manufacture liquid crystal displays, electroluminescence displays, surface emitting displays, and color filters. The liquid ejecting apparatus may include, for example, an apparatus that ejects bio organic matter to manufacture biochips, an apparatus used as a precision pipette that ejects liquid serving as a sample, printing equipment, and a microdispenser. The liquid ejecting apparatus may be an apparatus that ejects lubricating oil in a pinpoint manner onto a precision instrument such as a clock or a camera, an apparatus that sprays transparent liquid resin such as ultraviolet curing resin on a substrate in order to form a hemispherical microlens and an optical lens used in optical communication elements. The liquid ejecting apparatus 12 may be an apparatus that ejects acid, alkaline, or another etching solution for etching substrates and the like.
Technical ideas and the effects perceived from the exemplary embodiment and the modifications described above will be described below.
A liquid ejecting apparatus including a liquid ejecting head that ejects a liquid, a liquid storage portion that stores the liquid, a supply flow path that communicates the liquid ejecting head and the liquid storage portion with each other, and an air chamber that is coupled to the supply flow path through a plurality of flow paths. In the liquid ejecting apparatus, the supply flow path includes a filter, the plurality of flow paths are, in the supply flow path, connected upstream from the filter, and the air chamber is positioned at a position higher than the filter when in a first posture that is a posture during use.
According to such a configuration, when in first posture, since the air chamber coupled to the supply flow path at a portion upstream of the filter is positioned above the filter, there is air in the air chamber. Accordingly, even when the apparatus is turned over and is changed from the first posture to the second posture, the liquid upstream of the filter starts to move to the air chamber through the plurality of flow paths.
When changed to the second posture, since the liquid influenced by gravity moves into at least a portion of portions of the plurality of flow paths and the air chamber that are filled with air when in the first posture, the amount of liquid upstream of the filter decreases, and portions of the air in the plurality of flow paths and in the air chamber amounting to the volume of the liquid that has moved flows upstream of the filter. In other words, a layer of air is formed in the supply flow path between the liquid storage portion and the filter.
When, in the second posture, the liquid surface, which is an interface between the air and the liquid, and the filter overlap each other due to the layer of air between the liquid storage portion and the filter, meniscuses are formed in the capillary tubes formed by the pores in the filter and, due to the surface tensions of the meniscuses, a bubble point pressure, which is a pressure in the direction opposite the water load between the liquid storage portion and the filter, is generated. Furthermore, when, in the second posture, there is liquid on the upper surface of the filter, in other words, when the liquid surface is above the filter, no meniscus is formed; accordingly, due to the water load, the liquid leaks from the liquid ejecting head until the meniscuses are formed. Subsequently, leaking of the ink from the liquid ejecting head can be prevented after the meniscuses are formed in the upper surface of the filter. Accordingly, the amount of liquid leaking from the liquid ejecting head can be suppressed to a small amount. Accordingly, even when the liquid ejecting apparatus is turned over to a posture in which the position of the liquid surface in the liquid storage portion is higher than the position of the liquid ejecting head, leaking of the liquid from the liquid ejecting head can be suppressed.
(B) In the liquid ejecting apparatus described above, when in the first posture, the plurality of flow paths may be coupled to the supply flow path at a position higher than the filter.
According to such a configuration, when in the first posture, the air chamber is positioned vertically above the supply flow path that includes the filter, and the plurality of flow paths that couple the supply flow path and the air chamber to each other are coupled to the supply flow path at a position that is higher than that of the filter; accordingly, the air chamber and the plurality of flow paths are not included in the flow path of the liquid.
Accordingly, when in the first posture, there is, rather than the liquid, air in the air chamber and the plurality of flow paths. Furthermore, the plurality of flow paths are coupled upstream of the filter. Accordingly, when the apparatus is tuned over and is changed to the second posture from the first posture, the liquid in the supply flow path that was upstream of the filter starts to move towards the air chamber through at least one of the plurality of flow paths coupled upstream of the filter in the supply flow path. Since the air chamber and the plurality of flow paths are coupled to the supply flow path at positions that are higher than that of the filter, compared with when only the air chamber is positioned vertically above the filter, the amount of air moving to the air chamber is large.
(C) In the liquid ejecting apparatus described above, when in a second posture that is a posture in which the liquid storage portion is positioned higher than the liquid ejecting head, at least a portion of the air chamber may be positioned at a position lower than the filter.
According to such a configuration, when the apparatus is tuned over and is changed to the second posture from the first posture, the liquid that was upstream of the filter moves towards the air chamber through the plurality of flow paths coupled upstream of the filter in the supply flow path. Furthermore, since at least a portion of the air chamber is positioned at a position that is lower than that of the filter, the amount of liquid that moves to the air chamber is increased further.
When changed to the second posture, the liquid surface, which is an interface between the layer of air between the liquid storage portion and the filter and the liquid, can be made to overlap the filter or can be made to approach the upper surface of the filter. Accordingly, when in the second posture, the leaking of the liquid from the liquid ejecting head can be eliminated in a further reliable manner or, even if the liquid were to leak, the amount of leakage can be suppressed to a further small amount. Accordingly, leakage of the liquid from the liquid ejecting head can be suppressed.
(D) In the liquid ejecting apparatus described above, the supply flow path may include a filter chamber, the filter may be provided in the filter chamber, a ditch portion that is provided in the filter chamber, the ditch portion may be upstream from the filter, and the ditch portion may be at a position lower than an upstream surface of the filter when in the second posture, and at least one of the plurality of flow paths may be coupled to the ditch portion.
According to such a configuration, by having the liquid on the upstream surface of the filter flow to the low ditch portion around the filter, the liquid surface becomes flush with the upper surface of the filter or becomes lower than the upper surface of the filter, which facilitates formation of the meniscuses in the filter. Accordingly, when the posture of the liquid ejecting apparatus is changed from the first posture to the second posture, leaking of the liquid from the liquid ejecting head can be prevented.
(E) In the liquid ejecting apparatus described above, the air chamber may include a division wall that horizontally divides the air chamber when in the second posture.
According to such a configuration, when in the second posture and when the liquid ejecting apparatus is vibrated while being conveyed and the like in the second posture, movement of the liquid or the wave generated in the liquid is suppressed by having the liquid hit against the division wall horizontally dividing the air chamber. When, in the second posture, the liquid in the air chamber is bubbled, the volume of the liquid increases and the substantial amount of liquid accumulated in the air chamber becomes relatively small; accordingly, the liquid surface formed by the layer of air between the liquid storage portion and the filter rises above the anticipated height of the liquid surface. In such a case, inconveniences such as the meniscuses not being formed, and the amount of liquid leaking from the liquid ejecting head until the meniscuses are formed becoming large occur. However, since bubbling in the air chamber can be suppressed, the above inconvenience can be prevented to the utmost. Furthermore, bubbly liquid can be suppressed from entering the supply flow path.
(F) In the liquid ejecting apparatus described above, the division wall may be disposed at a position higher than a liquid surface in the air chamber when in the second posture.
According to such a configuration, when in the second posture B, there is little concern that the liquid that has moved to the air chamber below the division wall will return to upstream of the filter, and the volume at which the liquid covers the upper surface of the filter can be suppressed.
Note that when in the second posture, by having the volumetric capacity of the air chamber that is below the division wall and that is at a position lower than the position of the filter be larger than the volumetric capacity of the supply flow path upstream of the filter, the entire liquid upstream of the filter can be moved to the air chamber below the division wall. Accordingly, there are fewer incidents such as the liquid that has moved to the air chamber returning to the supply flow path upstream of the filter, and the liquid can be suppressed from covering the upper surface of the filter once again.
(G) In the liquid ejecting apparatus described above, the division wall may include a through hole that communicates two rooms with each other formed by dividing the air chamber with the division wall.
According to such a configuration, when in the second posture B, the liquid that has flowed into, among the two rooms that are the air chamber divided with the division wall, the upper room passes through the communication passage and moves to the room below the division wall; accordingly, the liquid can be collected in the lower portion of the air chamber.
(H) In the liquid ejecting apparatus described above, the air chamber may include a wall portion that protrudes in a direction intersecting the division wall.
According to such a configuration, a large movement of the liquid can be suppressed by dividing the rooms, which is the air chamber divided by the division wall, into small rooms with the wall portions and by hitting, against the wall portions, the wave generated in the liquid when the liquid ejecting apparatus is vibrated while being conveyed and the like. With the above, since a large wave is not generated in the liquid in the air chamber, bubbling of the liquid is suppressed. With the above, the frequency at which the meniscuses are not formed due to the liquid surface rising above the upstream surface of the filter, which is caused by the bubbling of the liquid in the air chamber, can be reduced, and the amount of liquid that leaks from the liquid ejecting head until the meniscuses are formed can be suppressed to a small amount. Furthermore, the bubbly liquid can be prevented from entering the supply flow path.
(I) In the liquid ejecting apparatus described above, at least a portion of the supply flow path upstream of the filter may pass a position lower than the filter when in the second posture
According to such a configuration, when the liquid ejecting apparatus is in the second posture, the portion of the supply flow path between the liquid storage portion and the filter passes through a position that is lower than the filter; accordingly, the air upstream of the filter does not easily flow out towards the liquid storage portion side through the supply flow path.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2019-156434 | Aug 2019 | JP | national |
