Patent Application
20200262198
The present application is based on, and claims priority from JP Application Serial Number 2019-025243, filed Feb. 15, 2019, the disclosure of which is hereby incorporated by reference herein in its entirety.
The present disclosure relates to a liquid ejecting head such as an ink jet recording head, and a liquid ejecting apparatus including the same, and more particularly, to a liquid ejecting head through which a liquid circulates between the liquid ejecting head and a liquid storage member, and a liquid ejecting apparatus.
A liquid ejecting apparatus is an apparatus which includes a liquid ejecting head and ejects (emits) various liquids as droplets from the liquid ejecting head. Examples of the liquid ejecting apparatus include an image recording apparatus such as an ink jet printer and an ink jet plotter. In recent years, the liquid ejecting apparatus has been applied to various manufacturing apparatuses, due to characteristics thereof that a very small amount of the liquid can be accurately landed at a predetermined position. For example, the liquid ejecting apparatus is applied to a display manufacturing apparatus for manufacturing a color filter such as a liquid crystal display, an electrode forming apparatus for forming an electrode of an organic electro-luminescence (EL) display, a surface light emission display (FED), or the like, and a chip manufacturing apparatus for manufacturing a biochip (biochemical element). A recording head for the image recording apparatus ejects a liquid containing a color material, and a color material ejecting head for the display manufacturing apparatus ejects a liquid containing color materials such as red, green, and blue. Further, an electrode material ejecting head for the electrode forming apparatus ejects a liquid containing an electrode material, and a bioorganic matter ejecting head for the chip manufacturing apparatus ejects a liquid containing a bioorganic matter.
The liquid ejecting head includes, for example, a nozzle board in which a plurality of nozzles are arranged side by side, a board on which a plurality of pressure chambers (or also referred to as pressure generation chambers or cavities) communicating with nozzles are formed, a board on which a supply liquid chamber (or also referred to as a reservoir or a manifold) is formed to be common to each pressure chamber into which a liquid from a liquid storage member is introduced, and a pressure generation element (or also referred to as a driving element or an actuator) such as a piezoelectric element, which causes pressure vibration in a liquid in the pressure chamber, in other words, a pressure change. Further, some liquid ejecting apparatuses including such a liquid ejecting head may be configured such that a plurality of head bodies (or heat units) having nozzle rows arranged side by side in a direction in which the nozzles are inclined with respect to a direction in which the medium is transported are arranged side by side in a direction perpendicular to the transport direction (for example, see JP-A-2015-136866). With this configuration, a flow path of the liquid flowing from a liquid storage member, such as a liquid tank and a liquid cartridge, which stores the liquid, to the nozzles of the liquid ejecting head is a one-way path. The liquid once supplied to the liquid ejecting head remains in the flow path inside the liquid ejecting head until the liquid is discharged from the nozzles.
In the above configuration, when bubbles are mixed with the liquid in the flow path inside the liquid ejecting head, the bubbles are unlikely to pass through a narrow flow path, and a buoyant force is applied. Therefore, the bubbles are unlikely to be discharged from the nozzle in a general liquid ejecting operation by driving the pressure generation element. Therefore, a so-called cleaning operation is required in which in order to discharge the bubbles, in a state in which a surface on which the nozzle is formed (hereinafter, also referred to as a nozzle surface) is sealed with a cap, a pressure difference between a space inside the cap and the inside of the flow path of the liquid ejecting head is caused with a pump or the like, so that the bubbles together with the liquid are discharged from the nozzle into the cap. However, there is a problem that the liquid is consumed more by the cleaning operation.
According to an aspect of the present disclosure, in order to achieve the above purposes, there is provided a liquid ejecting head including a plurality of head units that eject a liquid from nozzles onto a medium relatively moved in a first direction, and that are arranged side by side in a second direction perpendicular to the first direction, in which each of the head units includes: a nozzle row in which a plurality of nozzles are arranged side by side along a third direction intersecting the first direction and the second direction; pressure chambers which communicate with the nozzles; pressure generation elements which cause a pressure change in the liquid inside the pressure chambers; a supply liquid chamber which communicates with the pressure chambers and into which the liquid to be supplied to each of the pressure chambers is introduced; an inflow port through which the liquid flows into the head unit; and an outflow port through which the liquid flows out of the head unit.
Hereinafter, embodiments for carrying out the present disclosure will be described with reference to the accompanying drawings. In embodiments described below, there are various limitations as exemplary specific examples of the present disclosure. However, the scope of the present disclosure is not limited to these embodiments unless stated to particularly limit the present disclosure in the following description. Further, in the following description, an ink jet recording apparatus equipped with an ink jet recording head (a liquid ejecting head 2) which is one kind of a liquid ejecting head will be described as one form of a liquid ejecting apparatus 1 according to the present disclosure.
The liquid ejecting apparatus 1 includes a liquid ejecting head 2 including a plurality of the nozzle rows 7, a liquid storage member 3, a transport mechanism 4 that transports the medium M, a pump 6 through which an ink circulates between the liquid ejecting head 2 and the liquid storage member 3, and a control unit 5 that controls each portion of the liquid ejecting apparatus 1. The control unit 5 includes, for example, a processing circuit such as a central processing unit (CPU) and a field programmable gate array (FPGA) and a storage circuit such as a semiconductor memory, and comprehensively controls the transport mechanism 4, the pump 6, the liquid ejecting head 2, and the like in the liquid ejecting apparatus 1. The transport mechanism 4 transports the medium M in the Y direction from a paper feeding side to a paper discharging side under a control of the control unit 5. That is, the transport mechanism 4 relatively moves the liquid ejecting head 2 and the medium M in the Y direction. The liquid storage member 3 is a liquid storage member that may have various forms, such as a tank type, a cartridge type, and a pack type, which store ink ejected from the liquid ejecting head 2. The ink circulates between the liquid storage member 3 and the liquid ejecting head 2 by driving the pump 6 that functions as a liquid feeding mechanism. A liquid storage member serving as a buffer may be separately provided between the liquid storage member 3 and the liquid ejecting head 2. Further, a configuration may be employed in which the ink does not circulate between the liquid storage member 3 and the liquid ejecting head 2 and the ink individually circulates in each head unit 10.
In the present embodiment, the liquid ejecting head 2 includes the plurality of head units 10, a common wiring board 11, a flow path unit 12, and a fixing plate 13. In more detail, the head units 10 are joined to the fixing plate 13 in a state of being arranged side by side in the X direction, and the flow path unit 12 and the common wiring board 11 are sequentially stacked on the head units 10. Each head unit 10 is provided with a wiring member 14 having one end electrically coupled to a piezoelectric element 27 described below. The wiring member 14 is a flexible wiring material, such as a Chip On Film (COF), which electrically connects the piezoelectric element 27 of each head unit 10 and the common wiring board 11. Each wiring member 14 is inserted through a wiring entry port 16 formed in the flow path unit 12, and has the other end electrically joined to the common wiring board 11.
The common wiring board 11 is a board provided with a connector 15 to which wiring, such as printed wiring that is not illustrated and FFC that is not illustrated and is electrically coupled to the control unit 5, is coupled. In the present embodiment, a plurality of board terminal portions 19, in which a plurality of terminals for electrical connection to the wiring members 14 of the head units 10 are arranged side by side in the W direction, are provided on the upper surface of the common wiring board 11, that is, a surface opposite to a lower surface facing the flow path unit 12, to correspond to the head units 10, respectively. A distance d from one end of the board terminal portion 19 to one end of the common wiring board 11 (in other words, one side edge of the common wiring board 11 in the Y direction) in the W direction is made uniform at each board terminal portion 19. That is, the board terminal portions 19 are arranged side by side in the X direction along a side edge of the common wiring board 11. Further, concave notch portions 18 are formed on both side edges of the common wiring board 11 in the X direction. The dimension of the notch portion 18 in the W direction is set slightly larger than the width of the wiring member 14 in the W direction. The wiring member 14 (in the present embodiment, a wiring member 14-1 and a wiring member 14-6) coupled to the head units 10 located at opposite end portions in the X direction among the plurality of head units 10 is arranged in this notch portion 18. Among them, the board terminal portion 19 is formed adjacent to the other notch portion 18 in the V direction with respect to the one notch portion 18 in the X direction. Similarly, the board terminal portion 19 is formed adjacent to the one notch portion 18 in the V direction with respect to the other notch portion 18 in the X direction. That is, the board terminal portions 19 are formed adjacent to a central axis of the common wiring board 11 indicated by a point C2 in the drawings with respect to the notch portion 18. Further, in an area between the notch portions 18 of the common wiring board 11 in the X direction, wiring insertion ports 17, into which the wiring member 14 of the remaining head units 10 except for the head units 10 located at both ends in the X direction among the head units 10 are inserted, are formed to correspond to the board terminal portions 19, respectively. In a positional relationship between the wiring insertion port 17 and the board terminal portion 19, the even-numbered board terminal portions 19 counted from one end in the X direction are located on sides of the wiring insertion ports 17 in the X direction, respectively, and the odd-numbered board terminal portions 19 are located on the other sides of the wiring insertion ports 17 in the X direction, respectively.
The wiring member 14 has a first connection portion 14a, a second connection portion 14b, and a relay portion 14c. The first connection portion 14a and the second connection portion 14b are portions located at both ends of the wiring member 14. That is, in the wiring member 14, the relay portion 14c is located between the first connection portion 14a and the second connection portion 14b. As illustrated in
In the above configuration, similar to the odd-numbered wiring members 14-1, 14-3, and 14-5 counted from one end in the X direction, as illustrated in
By adopting such a configuration, the tip ends of the second connection portions 14b of the wiring members 14 located at both ends in the X direction among the plurality of wiring members 14 coupled to the common wiring board 11 face the inner side in the X direction (that is, the center side of the common wiring board 11). Thus, in the common wiring board 11, a space for arranging wirings, terminals, and the like outside the wiring members 14 located at both ends in the X direction becomes unnecessary. Accordingly, the size of the common wiring board 11 can be reduced to that extent. As a result, the size of the liquid ejecting head 2 can be reduced. That is, as illustrated in
The flow path unit 12 disposed between the common wiring board 11 and the head unit 10 is a structure having a flow path formed herein, and distributes the ink supplied from a supply port 21 to the head unit 10. The fixing plate 13 is a flat plate member that supports the head unit 10, and is formed of, for example, a metal plate such as stainless steel. The fixing plate 13 is formed with a plurality of the opening portions 22 corresponding to the plurality of head units 10, respectively. When the head unit 10 is joined to the fixing plate 13 in a state in which the head unit 10 is positioned, the opening portion 22 is configured such that the nozzle 8 of the head unit 10 is exposed to the lower surface of the fixing plate 13, that is, a surface facing the medium M during a printing operation. In the drawing, a configuration including six head units 10 is illustrated. However, the number of the head units 10 is not limited to that illustrated, and may increase or decrease according to the specification of the liquid ejecting apparatus 1 as in the embodiments described below.
The flow path board 24 in the present embodiment is formed of, for example, a silicon single crystal board, and has a common introduction liquid chamber 39, a first individual communication path 45, a nozzle communication path 46, a second individual communication path 47, and a common discharge liquid chamber 41. The pressure chamber board 26 and the protective board 28 are joined to each other on the upper surface of the flow path board 24 in the Z direction while being stacked in the order thereof. Further, as described below, in a state in which the pressure chamber board 26 and the protective board 28 are accommodated in a wiring space 31, the common flow path board 29 is bonded. Further, a nozzle board 35 is joined to a central portion in the X direction on the lower surface of the flow path board 24 in the Z direction. A first compliance board 36 and a second compliance board 37 are joined to both sides of the nozzle board 35 pinched therebetween.
The common introduction liquid chamber 39 is a liquid chamber that extends in a nozzle row direction in which the nozzles 8 are arranged side by side, in other words, along the W direction, and communicates with a plurality of the pressure chambers 25. An opening of the common introduction liquid chamber 39 on the upper surface of the flow path board 24 communicates with an introduction liquid chamber 32 of the common flow path board 29. Further, the opening of the common introduction liquid chamber 39 on the lower surface of the flow path board 24 is closed by the first compliance board 36 which is joined to the lower surface of the flow path board 24 and will be described below. The first individual communication path 45 is a flow path through which the plurality of pressure chambers 25 formed on the pressure chamber board 26 and the common introduction liquid chamber 39 (that is, a supply liquid chamber 40) individually communicate with each other. A plurality of the individual communication paths 45 are provided to correspond to the pressure chambers 25. In other words, the first individual communication path 45 is a flow path communicating with the pressure chamber 25 from the supply liquid chamber 40. The first individual communication path 45 has a flow path cross-section that is smaller than that of the other portion of the flow path from the liquid storage member 3 toward the pressure chamber 25, and thus imparts flow path resistance to the ink passing through the first individual communication path 45.
The nozzle communication path 46 is a flow path penetrated in the thickness direction of the flow path board 24, and causes the nozzle 8 of the nozzle board 35 joined to the lower surface of the flow path board 24 and the pressure chamber 25 corresponding to the nozzle 8 to communicate with each other. The second individual communication path 47 is a flow path individually formed to correspond to each nozzle 8. One end of the second individual communication path 47 communicates with the nozzle communication path 46. Further, the other end of the second individual communication path 47 communicates with the common discharge liquid chamber 41 (in other words, a discharge liquid chamber 43 described later). The first individual communication path 45, the pressure chamber 25, the nozzle communication path 46, and the second individual communication path 47 in the present embodiment are individual flow paths individually provided in each nozzle 8.
The common discharge liquid chamber 41 is a liquid chamber extending in the W direction, and communicates with the plurality of nozzles 8 through the second individual communication path 47. That is, the common discharge liquid chamber 41 is a liquid chamber common to the plurality of nozzles 8. An opening on the upper surface side of the common discharge liquid chamber 41 in the flow path board 24 communicates with a discharge liquid chamber 33 of the common flow path board 29. An opening on the lower surface side of the common discharge liquid chamber 41 in the flow path board 24 is closed by the second compliance board 37.
The pressure chamber board 26 is a plate-like member having an area that is smaller than the common flow path board 29 in a plan view from the Z direction, and is formed of a silicon single crystal board or the like, which is like the common flow path board 29. The pressure chamber 25 formed on the pressure chamber board 26 is a liquid chamber that is elongated in the V direction perpendicular to the W direction, and is open on the lower surface of the pressure chamber board 26. As the pressure chamber board 26 is joined to the upper surface of the flow path board 24, the opening is closed and the pressure chamber 25 is defined. One end (a right end in
In the pressure chamber board 26, a flexible diaphragm 23 is provided on the upper surface side of the pressure chamber 25. The diaphragm 23 is a portion formed in a thin plate shape that is displaceable according to driving of the piezoelectric element 27 functioning as a pressure generation element. The piezoelectric element 27 is formed in a portion corresponding to the pressure chamber 25 on the diaphragm 23. The piezoelectric element 27 is a drive element individually provided to correspond to the pressure chamber 25 and is deformed in response to a drive signal from the control unit 5. As the diaphragm 23 is deformed with the deformation of the piezoelectric element 27, the volume of the pressure chamber 25 increases or decreases. Accordingly, pressure vibration (in other words, pressure change) occurs in the ink in the pressure chamber 25. In the head unit 10, droplets, that is, ink droplets, are ejected from the nozzles 8 using the pressure vibration.
The first compliance board 36 is a board that absorbs the pressure vibration propagating from the pressure chamber 25 side into the supply liquid chamber 40, which will be described below, when the ink droplets are ejected from the nozzles 8, and suppresses variations in ejection characteristics (that is, the amount, the ejection speed or the like of the ink droplets) between the nozzles 8. The first compliance board 36 and the second compliance board 37, which will be described below, have flexible film-like thin films (for example, thin films formed of polyphenylene sulfide (PPS), aromatic polyamide (aramid), or the like) that is not illustrated. The thin film absorbs the pressure vibration by being displaced according to the pressure vibration of the ink in the liquid chamber.
The nozzle board 35 is joined to the lower surface of the flow path board 24 and closes the openings of the nozzle communication path 46 and the second individual communication path 47. In the nozzle board 35 in the present embodiment, for example, as drying etching, wet etching or the like are performed on a silicon (Si) single crystal board, the plurality of nozzles 8 are arranged side by side at a predetermined pitch to form the nozzle row 7. The nozzle 8 is a circular through-hole that ejects the ink, and various already-known shapes can be employed as the nozzle 8. In
The protective board 28 is formed with a concave accommodation space 48 corresponding to a formation area of the piezoelectric element 27 provided on the diaphragm 23 of the pressure chamber board 26. The protective board 28 is joined to the upper surface of the pressure chamber board 26 to accommodate the piezoelectric element 27 in the accommodation space 48. Further, the protective board 28 has a wiring through-hole 49 penetrated in a board thickness direction for the purpose of installation of the wiring member 14 coupled to a lead electrode 30 pulled out from the piezoelectric element 27.
The common flow path board 29 has a wiring space 31 penetrated in the height direction (that is, the Z direction) in a central portion. Further, in a state in which the common flow path board 29 is joined to the flow path board 24, the pressure chamber board 26 and the protective board 28 provided on the upper surface of the flow path board 24 are stacked and arranged in the wiring space 31 of the common flow path board 29. Further, the wiring member 14 coupled to the piezoelectric element 27 is disposed in the wiring space 31.
In the common flow path board 29, the introduction liquid chamber 32 and the discharge liquid chamber 33 are formed on both sides of the wiring space 31 in the X direction, respectively. The introduction liquid chamber 32 is open on the lower surface of the common flow path board 29, and the opening is closed by the flow path board 24 and communicates with the common introduction liquid chamber 39 formed in the flow path board 24. The common introduction liquid chamber 39 and the introduction liquid chamber 32 communicate with each other in series to partition one supply liquid chamber 40. The supply liquid chamber 40 is a liquid chamber shared for supplying the ink to the plurality of pressure chambers 25. Similarly, the discharge liquid chamber 33 is open on the lower surface of the common flow path board 29, and communicates with the common discharge liquid chamber 41 of the flow path board 24 to partition the discharge liquid chamber 43. The discharge liquid chamber 43 is a liquid chamber into which the ink that has not been ejected from the nozzle 8 flows from the supply liquid chamber 40 through an individual flow path such as the pressure chamber 25.
An inflow port 38 communicating with the supply liquid chamber 40 and an outflow port 44 communicating with the discharge liquid chamber 43 are formed on the upper surface of the common flow path board 29. That is, the inflow port 38 is a through-hole through which the ink flows into the head unit 10, and the outflow port 44 is a through-hole through which the ink flows out of the head unit 10. The formation positions and the numbers of the inflow ports 38 and the outflow ports 44 differ depending on embodiments described below.
Next, in the embodiment of the liquid ejecting apparatus 1 according to the present disclosure, arrangement of the nozzles 8 and the nozzle rows 7 and circulation of the ink will be described mainly.
In the present embodiment, in the liquid ejecting head 2, three head units 10a to 10c are arranged side by side in the X direction, and each of the head units 10a to 10c includes one nozzle row 7. The nozzle rows 7a to 7c of the head units 10 are formed along the W direction that is perpendicular to the Z direction and is inclined with respect to the X direction and the Y direction, and any of them ejects the same kind of ink, that is, ink having the same color (for example, black). As illustrated in
Further, in the present embodiment, only the supply liquid chamber 40 in the head unit 10 is used, and the discharge liquid chamber 43 and the second individual communication path 47 are not used. The supply liquid chamber 40 in the present embodiment is provided with both the inflow port 38 and the outflow port 44. In an example of
In the present embodiment, during the printing operation by the liquid ejecting head 2, the ink circulates by driving the pump 6 between the liquid storage member 3 and the supply liquid chamber 40 of the head unit 10. That is, the ink sent from the liquid storage member 3 is introduced into the supply liquid chamber 40 from the inflow port 38. The ink in the supply liquid chamber 40 is supplied to the pressure chamber 25 through the first individual communication path 45 (see
In this way, in a configuration of the present embodiment, the supply liquid chamber 40 is provided with the inflow port 38 and the outflow port 44, and the ink can circulate therebetween. Thus, even when bubbles are generated in a flow path inside the head unit 10, the bubbles can be discharged to the outside of the head unit 10. As a result, the number of times of so-called maintenance operations, such as a cleaning operation and a flushing operation, for forcibly discharging the ink inside the head unit 10 from the nozzle 8 can be reduced, and the amount of the ink consumed in the maintenance operation can be reduced. Further, since the supply liquid chamber 40 is provided with the inflow port 38 and the outflow port 44, the discharge liquid chamber 43 and the second individual communication path 47 are not required. Since the head unit 10 can be downsized to that extent, a configuration can be employed in which the ink circulates in a smaller space.
In the present embodiment, a configuration in which the ink circulates between the liquid storage member 3 and the supply liquid chamber 40 of the head unit 10 is illustrated. However, the present disclosure is not limited thereto. For example, a configuration may be employed in which a circulation flow path connecting the inflow port 38 and the outflow port 44, a filter provided in the circulation flow path, and a circulation pump are provided in the head unit 10, and the ink circulates without using the liquid storage member 3. In this case, an introduction port for introducing the ink from the liquid storage member 3 into the supply liquid chamber 40 is provided separately from the inflow port 38. Further, the positions of the inflow port 38 and the outflow port 44 in the supply liquid chamber 40 are not limited to the illustrated configuration. For example, a positional relationship between the inflow port 38 and the outflow port 44 may be opposite to that illustrated in
In the present embodiment, odd-numbered nozzle rows 7a, 7c, and 7e in which the nozzles 8 are indicated by white circles in
In the first modification example, a configuration is exemplified in which the odd-numbered nozzle rows 7a, 7c, and 7e in which the nozzles 8 are indicated by white circles in
As illustrated in
As illustrated in
As illustrated in
In the third modification example, a configuration in which the same type (that is, the same color) of ink is ejected to all the nozzle rows 7 is described as an example. However, the present disclosure is not limited thereto, and a configuration in which different types of ink are ejected to the first nozzle row 7-1 and the second nozzle row 7-2 of the head unit 10 can be employed as a fourth modification example of the first embodiment. In this case, when viewed from the Y direction, the nozzles 8 are arranged at the pitch P2 in the X direction for each type of ink. Further, in a fifth modification example of the first embodiment, as different types of ink from the two types of ink are ejected to the odd-numbered head units 10 and the even-numbered head units 10, a total of four types of ink can be ejected. For example, black ink is ejected from the first nozzle rows 7a-1, 7c-1, and 7e-1 of the odd-numbered head units 10a, 10c, and 10e, and cyan ink is ejected from the second nozzle rows 7a-2, 7c-2, and 7e-2 of the odd-numbered head units 10a, 10c, and 10e. Further, magenta ink is ejected from the first nozzle rows 7b-1, 7d-1, and 7f-1 of the even-numbered head units 10b, 10d, and 10f, and yellow ink is ejected from the other nozzle rows 7b-2, 7d-2, and 7f-2 of the even-numbered head units 10b, 10d, and 10f. Thus, the printing can be performed using four colors of ink. That is, a printing operation is performed using three nozzle rows 7 for one type (that is, one color) of ink.
In the present embodiment, when the ink circulates by driving the pump 6, if the ink is introduced from the inflow port 38 to the supply liquid chamber 40, the ink in the supply liquid chamber 40 flows along the W direction as indicated by a hatching arrow and is supplied to the pressure chamber 25 through the first individual communication path 45. Further, the ink, which has not been ejected from the nozzle 8, flows into the discharge liquid chamber 43 through the second individual communication path 47 as indicated by a black arrow. That is, the ink flows from the supply liquid chamber 40 into the discharge liquid chamber 43 through the pressure chamber 25. The ink, which has flowed into the discharge liquid chamber 43, is sent out from the outflow port 44 and returns to the liquid storage member 3. While the pump 6 is driven, the ink continuously circulates between the inflow port 38 and the outflow port 44. The other configurations are the same as those of the first embodiment illustrated in
The ink can circulate even in the configuration of the present embodiment. Thus, even when bubbles are generated inside the head unit 10, the bubbles can be discharged to the outside of the head unit 10. As a result, the number of times of so-called maintenance operations, such as a cleaning operation and a flushing operation, for forcibly discharging the ink inside the head unit 10 from the nozzle 8 can be reduced, and the amount of the ink consumed in the maintenance operation can be reduced. Further, since the ink circulates through the individual flow path, which is a flow path provided in each nozzle 8, such as the pressure chamber 25, it is possible to suppress the thickening of the ink near the nozzles 8 and the sedimentation of contained components in the ink. Accordingly, the number of times of maintenance operations can be further reduced. Further, since the ink circulates through the individual flow path such as the pressure chamber 25, it is possible to suppress the thickening of the ink near the nozzles 8 and the sedimentation of the contained components in the ink. Accordingly, the number of times of maintenance operations can be further reduced.
In the first modification example, a configuration is exemplified in which the odd-numbered nozzle rows 7a, 7c, and 7e and the even-numbered nozzles 7b, 7d, and 7f in which the nozzles 8 are indicated by black circles in the same drawing eject different types of ink. However, the present disclosure is not limited to this configuration, and a configuration in which the same type of ink is ejected to the nozzle rows 7a to 7f can be employed as a second modification example of the second embodiment. In this case, in an area in which formation areas of the nozzle rows 7 overlap each other when viewed from the Y direction, the nozzle density in the X direction when the nozzles 8 are arranged at the pitch P2 in the X direction (for example, a pitch corresponding to 1200 dpi) is doubled as compared to a configuration in which the nozzles 8 are arranged at the pitch P1. Therefore, printing and recording can be performed with higher resolution.
In the present embodiment, similar to the first embodiment, in the liquid ejecting head 2, three head units 10a to 10c are arranged side by side in the X direction, and each of the head units 10a to 10c includes two nozzle rows 7. The head unit 10a includes a first nozzle row 7a-1 disposed on one side (a −V direction side) in the V direction and a second nozzle row 7a-2 disposed on the other side (a +V direction side) in the V direction. Similarly, a head unit 10b includes a first nozzle row 7b-1 and a second nozzle row 7b-2, and a head unit 10c includes a first nozzle row 7c-1 and a second nozzle row 7c-2. The length L of the first nozzle row 7-1 and the second nozzle row 7-2 and a distance D from the nozzle 8 located at one end of the head unit 10 in the W direction (in an example of
As illustrated in
In the present embodiment, the head unit 10 is provided with two supply liquid chambers 40 corresponding to the first nozzle row 7-1 and the second nozzle row 7-2, respectively. That is, as illustrated in
In the present embodiment, when the ink circulates, if the ink sent from the liquid storage member 3 is introduced from the inflow port 38 to the supply liquid chambers 40a and 40b, as indicated by hatching arrows in
In the present embodiment, in the liquid ejecting head 2, three head units 10a to 10c are arranged side by side in the X direction, and each of the head units 10a to 10c includes the first nozzle row 7-1 and the second nozzle row 7-2. In detail, as illustrated in
As illustrated in
As illustrated in
In the present embodiment, the head unit 10 is provided with two supply liquid chambers 40 corresponding to the first nozzle row 7-1 and the second nozzle row 7-2, respectively. That is, as illustrated in
In the present embodiment, when the ink circulates, if the ink sent from the liquid storage member 3 is introduced from the inflow port 38 to the supply liquid chambers 40a and 40b, as indicated by hatching arrows in
In the present embodiment, in the head unit 10, the first nozzle row 7-1 and the second nozzle row 7-2 are provided with the supply liquid chamber 40 and the discharge liquid chamber 43. That is, as illustrated in
Each of the first supply liquid chamber 40a and the second supply liquid chamber 40b is provided with the inflow port 38. Further, each of the first discharge liquid chamber 43a and the second discharge liquid chamber 43b is provided with the outflow port 44. In the present embodiment, a central portion of each of the first supply liquid chamber 40a and the second supply liquid chamber 40b in the W direction is provided with the inflow port 38, and a central portion of each of the first discharge liquid chamber 43a and the second discharge liquid chamber 43b in the W direction is provided with the outflow port 44. That is, similar to the first nozzle row 7a-1 and the second nozzle row 7a-2, the first supply liquid chamber 40a and the second supply liquid chamber 40b are arranged to be point-symmetric to each other with respect to the center C4 of the nozzle board 35. Similarly, the first discharge liquid chamber 43a and the second discharge liquid chamber 43b are arranged to be point-symmetric to each other with respect to the center C4 of the nozzle board 35. The position of the inflow port 38 in the supply liquid chamber 40 and the position of the outflow port 44 in the discharge liquid chamber 43 are not limited to the illustrated configuration, and can be set in a predetermined position.
In the present embodiment, when the ink circulates, if the ink is introduced from the inflow port 38 to the supply liquid chamber 40, the ink in the supply liquid chamber 40 flows along the W direction as indicated by a hatching arrow and is supplied to the pressure chamber 25 through the first individual communication path 45. The ink, which has not been ejected from the nozzle 8, flows into the discharge liquid chamber 43 through the second individual communication path 47 as indicated by a black arrow. That is, the ink flows from the supply liquid chamber 40 into the discharge liquid chamber 43 through the pressure chamber 25. The ink, which has flowed into the discharge liquid chamber 43, is sent out from the outflow port 44 and returns to the liquid storage member 3. While the pump 6 is driven, the ink continuously circulates between the inflow port 38 and the outflow port 44. The other configurations are the same as those of the first embodiment illustrated in
As described above, in the liquid ejecting head 2 and the liquid ejecting apparatus 1 including the same according to the present disclosure, since the head unit 10 is provided with the inflow port 38 and the outflow port 44, and the liquid can circulate therebetween, the number of times of so-called maintenance operations, such as a cleaning operation and a flushing operation, for forcibly discharging thickened ink and bubbles inside the head unit 10 from the nozzles, can be reduced, so that the amount of the liquid consumed for the maintenance operations can be reduced. As a result, ejection characteristics of the nozzle 8 (that is, characteristics such as the amount of ejected ink droplets and a flying speed of the ink droplets) can be favorably maintained even while consumption of the ink is reduced.
In the above-described embodiments, in a configuration in which the nozzle board 35 includes the nozzle row 7-1 and the nozzle row 7-2, a configuration in which the nozzle row 7-1 and the nozzle row 7-2 are arranged to be point-symmetric to each other with respect to the center C4 of the nozzle board 35 is illustrated. However, the present disclosure is not limited thereto. In short, when viewed from the +Z direction, among the nozzle row 7-1 and the nozzle row 7-2, the nozzle row 7-1 and the nozzle row 7-2 may be arranged to be point-symmetric to each other with respect to a central point of a virtual straight line connecting the nozzle 8 disposed at an end portion on the most +W direction side and the nozzle 8 disposed at an end portion on the most −W direction side, and the central point and the center C4 of the nozzle board 35 may not be necessarily coincide with each other. Further, in the fifth embodiment, a configuration can be employed in which the supply liquid chamber 40a and the supply liquid chamber 40b are arranged to be point-symmetric to each other with respect to the central point and the discharge liquid chamber 43a and the discharge liquid chamber 43b are arranged to be point-symmetric to each other with respect to the central point.
In addition, the present disclosure can be applied to a liquid ejecting head and a liquid ejecting apparatus including the same, the liquid ejecting head including a plurality of color material ejecting heads used for manufacturing a color filter, such as a liquid crystal display, a plurality of electrode material ejecting heads used for forming an electrode, such as an organic electro luminescence display (EL) and a surface emitting display (FED), a plurality of bioorganic material ejecting heads used for manufacturing a biochip (biochemical elements), or the like.
Hereinafter, the technical spirit and the effect, which are grasped in the above-described embodiments and modification examples, will be described.
According to an aspect of the present disclosure, there is provided a liquid ejecting head in which a plurality of head units for ejecting a liquid from nozzles onto a medium that is relatively moved in a first direction are arranged side by side in a second direction perpendicular to the first direction, in which the head unit includes: a nozzle row in which the plurality of nozzles are arranged side by side along a third direction intersecting the first direction and the second direction; a pressure chamber which communicates with the nozzles; a pressure generation element which causes a pressure change in the liquid inside the pressure chamber; a supply liquid chamber which communicates with a plurality of the pressure chambers and into which the liquid to be supplied to each pressure chamber is introduced; an inflow port through which the liquid flows into the head unit; and an outflow port through which the liquid flows out of the head unit (first configuration).
With this configuration, the inflow port and the outflow port are provided, and the liquid can circulate therebetween. Therefore, even when bubbles are generated in a flow path inside the head unit, the bubbles can be discharged. As a result, the number of times of so-called maintenance operations, such as a cleaning operation and a flushing operation, for forcibly discharging the liquid inside the head unit from the nozzles, can be reduced, and the amount of the liquid consumed for the maintenance operations can be reduced.
Further, in the first configuration, a configuration can be employed in which the inflow port and the outflow port are provided in the supply liquid chamber (second configuration).
With this configuration, since the inflow port and the outflow port are provided in the supply liquid chamber, a configuration can be employed in which the liquid circulates in a smaller space.
Further, in the first configuration, a configuration can be employed in which the head unit includes a discharge liquid chamber which communicate with the plurality of pressure chambers and into which the liquid flows from the supply liquid chamber via the pressure chambers, the inflow port is provided in the supply liquid chamber, and the outflow port is provided in the discharge liquid chamber (third configuration).
With this configuration, since the liquid circulates via a flow path, individually provided in each nozzle, such as the pressure chamber, the thickening of the liquid near the nozzle and the sedimentation of the contained components in the liquid can be suppressed. Accordingly, the number of times of maintenance operations can be further reduced.
In the second configuration, a configuration can be employed in which the nozzle row has a first nozzle row and a second nozzle row that are arranged in a fourth direction that is perpendicular to the third direction and are biased to be opposite to each other in the third direction, the supply liquid chamber includes a first supply liquid chamber that communicates with the plurality of pressure chambers corresponding to the first nozzle row and a second supply liquid chamber that communicates with the plurality of pressure chambers corresponding to the second nozzle row, the first supply liquid chamber includes a first portion that extends in parallel to the first nozzle row in the third direction and a second portion that is continuous with the first portion and extends beyond an and of the first nozzle row, the second supply liquid chamber includes a third portion that extends in parallel to the second nozzle row in the third direction and a fourth direction that is continuous with the third portion and extends beyond an end of the second nozzle row, the first supply liquid chamber and the second supply liquid chamber are provided with the inflow port and the outflow port, respectively, and the first nozzle row and the second nozzle row are arranged to be point-symmetric to each other and have an overlapping portion in an area where the nozzles are formed when viewed from the fourth direction (fourth configuration).
With this configuration, the first supply liquid chamber and the second supply liquid chamber are provided to correspond to the first nozzle row and the second nozzle row, the inflow port and the outflow port are provided in each of the supply liquid chambers, and the liquid can circulate in each supply liquid chamber. Thus, even when bubbles are generated in a flow path inside the head unit, the bubbles can be discharged. As a result, the number of times of so-called maintenance operations, such as a cleaning operation and a flushing operation, for forcibly discharging the liquid inside the head unit from the nozzles, can be reduced, and the amount of the liquid consumed for the maintenance operations can be reduced. Further, since the first nozzle row and the second nozzle row are arranged to be point-symmetric to each other, and have the overlapping portion in the area where the nozzles are formed when viewed in the fourth direction, an area in which the first nozzle row and the second nozzle row are arranged in the first direction can be shortened.
In the third configuration, a configuration can be employed in which the nozzle row has a first nozzle row and a second nozzle row which are arranged side by side in a fourth direction perpendicular to the third direction, the supply liquid chamber includes a first supply liquid chamber which communicates with the plurality of pressure chambers corresponding to the first nozzle row and a second supply liquid chamber which communicates with the plurality of pressure chambers corresponding to the second nozzle row, the discharge liquid chamber includes a first discharge liquid chamber which communicates with the plurality of pressure chambers corresponding to the first nozzle row and into which the liquid flows from the first supply liquid chamber through the pressure chamber and a second discharge liquid chamber which communicates with the plurality of pressure chambers corresponding to the second nozzle row and into which the liquid flows from the second supply liquid chamber through the pressure chamber, the inflow port is provided in each of the first supply liquid chamber and the second supply liquid chamber, the outflow port is provided in each of the first discharge liquid chamber and the second discharge liquid chamber, and the first nozzle row and the second nozzle row are arranged to be point-symmetric to each other and are spaced apart from each other in the third direction (fifth configuration).
With this configuration, the first supply liquid chamber and the second supply liquid chamber are provided to correspond to the first nozzle row and the second nozzle row, the inflow port and the outflow port are provided in each of the supply liquid chambers, and the liquid can circulate in each supply liquid chamber. Thus, even when bubbles are generated in a flow path inside the head unit, the bubbles can be discharged. As a result, the number of times of so-called maintenance operations, such as a cleaning operation and a flushing operation, for forcibly discharging the liquid inside the head unit from the nozzles, can be reduced, and the amount of the liquid consumed for the maintenance operations can be reduced. Further, since the liquid circulates via a flow path, individually provided in each nozzle, such as the pressure chamber, the thickening of the liquid near the nozzle and the sedimentation of the contained components in the liquid can be suppressed. Accordingly, the number of times of maintenance operations can be further reduced.
In the fourth configuration and the fifth configuration, a configuration may be employed in which the plurality of nozzles of the first nozzle row and the plurality of nozzles of the second nozzle row provided in the same head unit are continuously arranged at a constant interval in the second direction when viewed from the first direction (sixth configuration).
With this configuration, dots of landing droplets can be continuously formed at a constant pitch in the second direction on the medium using the first nozzle row and the second nozzle row of the head unit.
In any one of the fourth to sixth configurations, a configuration may be employed in which the head unit includes a wiring member electrically coupled to the piezoelectric element, the liquid ejecting head includes a common wiring board electrically coupled to a plurality of the wiring members, and the odd-numbered wiring members of the head unit counted from one end in the second direction and the even-numbered wiring members of the head unit counted from the one end in the second direction are arranged to be point-symmetric to each other with respect to the third direction.
With this configuration, in the common wiring board, a space where wirings are arranged outside the wiring members located at both ends in the second direction becomes unnecessary. Accordingly, the common wiring board can be downsized, and as a result, the liquid ejecting head can be downsized. Accordingly, when the plurality of liquid ejecting heads are arranged side by side in the second direction, the liquid ejecting heads can be brought closer to each other, and the nozzles of the head units included in the liquid ejecting head can be arranged side by side at a constant pitch in the second direction.
The liquid ejecting apparatus according to the present disclosure includes the liquid ejecting head having any one of the first to seventh configurations, and a transport mechanism that transports a medium in the first direction.
According to the present disclosure, even while consumption of the liquid is reduced, ejection characteristics of each nozzle can be favorably maintained.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2019-025243 | Feb 2019 | JP | national |
