1. Field of the Invention
The present invention relates to a liquid jet head and a liquid jet apparatus for ejecting liquid from a nozzle to record graphics and characters on a recording medium, or to form a functional thin film thereon.
2. Description of the Related Art
In recent years, there has been used an ink-let type liquid jet head for ejecting ink droplets on recording paper or the like to record characters or graphics thereon, or for ejecting a liquid material on a surface of an element substrate to form a functional thin film thereon. In such a liquid jet head, ink or a liquid material, is supplied from a liquid tank via a supply tube to the liquid jet head, and ink or a liquid material filled into a channel is ejected from a nozzle which communicates with the channel. When ink is ejected, the liquid jet head or a recording medium on which a pattern of jetted liquid is to be recorded is moved to record characters or graphics, or to form a functional thin film in a predetermined shape.
Japanese Patent Application Laid-open No. 2011-93200 describes a liquid jet head 100 of this type.
The liquid supplied from the liquid tank (not shown) flows into the liquid supply chamber 106 via the supply joint 105a, and is filled into the channel row formed of the plurality of channels. Then, the liquid flows out from the channel row toward the liquid discharge chamber 107, and returns to the liquid tank via the discharge joint 105b. Therefore, the liquid constantly circulates during driving. An air bubble and dust mixed into the liquid circulate and return to the liquid tank together with the liquid. Therefore, occurrence of nozzle clogging is reduced. As a result, liquid replacement and maintenance such as cleaning of the liquid jet head 100 are facilitated, the amount of liquid to be consumed during cleaning is reduced, and the consumption amount of the recording medium is reduced as well. Therefore, there is such an advantage that increase of running cost can be suppressed. Japanese Patent No. 4263742 also describes a liquid circulating type ink jet head.
As illustrated in a partial enlarged view of
The supply joint 105a of the flow path member 104 is positioned at substantially the longitudinal center of the liquid supply chamber 106, and the discharge joint 105b or the flow path member 104 is positioned at substantially the longitudinal center of the liquid discharge chamber 107. The liquid flows in via the supply joint 105a to fill the liquid supply chamber 106 up to both end portions thereof. Then, the liquid flows through the respective ejection channels 110a to be discharged to the liquid discharge chamber 107, and then returns to the liquid tank (not shown) via the discharge joint 105b.
However, in the liquid jet head 100 of this type, as illustrated in
The present invention has been made in view of the above-mentioned problem, and has an object to provide a liquid jet head capable of rapidly discharging an air bubble mixed into liquid to the outside.
According to an exemplary embodiment of the present invention, there is provided a liquid jet head, including: a supply port through which liquid is supplied; a discharge port through which the liquid is discharged; a liquid supply chamber communicated with the supply port; a liquid discharge chamber communicated with the discharge port; a channel row formed of a plurality of channels provided in parallel to each other between the liquid supply chamber and the liquid discharge chamber, the plurality of channels each being communicated with the liquid supply chamber and the liquid discharge chamber; a plurality of nozzles communicated with the plurality of channels, respectively; and a communication path for bypassing the liquid from the liquid supply chamber to the liquid discharge chamber.
Further, the communication path is provided in a vicinity of a channel farthest from a position of the supply port.
Further, the supply port is positioned at substantially a longitudinal center of one of the liquid supply chamber and the liquid discharge chamber. The communication path is provided in a vicinity of each of both ends of the channel row in a row direction.
Further, the supply port is positioned at one longitudinal end portion of the liquid supply chamber. The communication path is provided in a vicinity of an end portion of the channel row, which corresponds to another longitudinal end portion.
Further, the supply port is positioned at one longitudinal end portion of the liquid supply chamber. The discharge port is positioned at another longitudinal end portion of the liquid discharge chamber. The communication path is provided in a vicinity of each of both ends of the channel row in a row direction.
Further, the supply port is positioned at one longitudinal end portion of the liquid supply chamber. The discharge port is positioned at another longitudinal end portion of the liquid discharge chamber. The communication path is provided in a vicinity of an end portion of the channel row, which corresponds to the another longitudinal end portion.
Further, the communication path has a flow path resistance of liquid, which is smaller than a flow path resistance of liquid of the plurality of channels.
Further, the liquid jet head further includes; an actuator substrate having the channel row formed therein; a cover plate including the liquid supply chamber and the liquid discharge chamber, the cover plate being bonded to the actuator substrate; a flow path member including the supply port and the discharge port, the flow path member being bonded to the cover plate; and a nozzle plate including the plurality of nozzles, the nozzle plate being bonded to the actuator substrate.
Further, the channel row includes a dummy channel and an ejection channel which are alternately arrayed. The cover plate includes a slit between the channel row and each of the liquid supply chamber and the liquid discharge chamber. The liquid supply chamber and the liquid discharge chamber are communicated with the election channel via the slit, and each of the plurality of nozzles is communicated with the ejection channel.
Further, the communication path is provided in the cover plate.
Further, the communication path is provided in the actuator substrate.
According to an exemplary embodiment of the present invention, there is provided a liquid jet apparatus, including: the above-mentioned liquid jet head; a moving mechanism for reciprocating the liquid jet head; a liquid supply tube for supplying liquid to the liquid jet head; and a liquid tank for supplying the liquid to the liquid supply tube.
According to the present invention, the liquid jet head includes: the supply port through which liquid is supplied; the discharge port through which the liquid is discharged; the liquid supply chamber communicated with the supply port; the liquid discharge chamber communicated with the discharge port; the channel row formed of the plurality of channels provided in parallel to each other between the liquid supply chamber and the liquid discharge chamber, the plurality of channels each being communicated with the liquid supply chamber and the liquid discharge chamber; the plurality of nozzles communicated with the plurality of channels, respectively; and the communication path for bypassing the liquid from the liquid supply chamber to the liquid discharge chamber. With this, the air bubble mixed into the liquid may be carried toward an end portion of the liquid supply chamber to pass through the communication path, and be removed from the liquid discharge chamber to the outside. In this manner, deterioration of an ejection characteristic, which is caused by adhesion of the air bubble to the channels and channel opening portions, is prevented.
In the accompanying drawings:
(Basic Configurations)
In the liquid jet head 1 illustrated in
When liquid flows from a liquid tank (not shown) into the supply port 2, the liquid is filled into the liquid supply chamber 4, and the liquid flows into the respective channels 6 of the channel row 7 communicated with the liquid supply chamber 4. Part of the liquid flowing into the respective channels 6 is ejected from the nozzles 8, and the other part thereof flows out to the liquid discharge chamber 5 to return to the liquid tank via the discharge port 3.
Further, because the communication path 9 is provided, a liquid flow is generated also in a region of the liquid supply chamber 4 separated from the supply port 2. As a result, a liquid flow is generated in a direction crossing opening portions of the channels 6 separated from the supply port 2, the opening portions being opened to the liquid supply chamber 4. With this flow, an air bubble is less liable to adhere to the opening portions of the channels 6. In this manner, even when an air bubble is mixed into liquid, the air bubble is carried toward an end portion of the liquid supply chamber 4 by the liquid flow in the direction crossing the opening portions to pass through the communication path 9, and then removed from the liquid discharge chamber 5 to the outside. Further, even when the air bubble adheres so the opening portions of the channels 6, the adhering air bubble can be easily removed via the liquid discharge chamber 5 and the discharge port 3 by pumping liquid from the supply port 2 to carry the air bubble toward the communication path 9. As a result, maintenance is facilitated.
Note that, it is preferred that the communication path 9 be provided in the vicinity of the channel 6 farthest from the position of the supply port 2. In the liquid jet head 1 illustrated in
The liquid jet head 1 illustrated in
In this case, the supply port 2 and the discharge port 3 do not face each other. Therefore, there is an effect that, when a tube (now shown) is to be mounted to one port, a tube (not shown) mounted to the other port does not interrupt the mounting, and hence the tube can be easily mounted.
Note that, the communication path 9 illustrated in
Note that, when the communication paths 9 are arranged on both sides, regardless of which port is provided on the in-flow side, the communication path 9 farther from the port on the in-flow side helps discharging of the above-mentioned air bubble and foreign matters. In other words, any one of the ports may be used as the supply port 2 (or the discharge port 3).
Further, it is preferred that the groove width and the groove depth of the communication path 9 be set larger than the groove width and the groove depth of the channel 6 so that the flow path resistance of the communication path 9 between the liquid supply chamber 4 and the liquid discharge chamber 5 is smaller than the flow path resistance of the channel 6. Note that, as described later, in the case where the channel row 7 is formed by alternately arraying the ejection channels and the dummy channels, and the liquid is caused to flow into the channels 6 via the slits, it is preferred that the groove width of the communication path 9 be larger than the groove width of the slit. In the following, the present invention is specifically described by means of embodiments.
As illustrated in
The flow path member 14 includes the supply port 2 and the discharge port 3. The supply port 2 is communicated with the liquid supply chamber 4, and is positioned at substantially the center of the liquid supply chamber 4. The discharge port 3 is communicated with the liquid discharge chamber 5, and is positioned at substantially the center of the liquid discharge chamber 5. The flow path member 14 includes a recessed portion 17 on the cover plate 11 side thereof so as to correspond to each of the liquid supply chamber 4 and the liquid discharge chamber 5. The recessed portion 17 forms a part of the liquid supply chamber 4 or a part of the liquid discharge chamber 5, thereby enlarging the flow path volume of the liquid supply chamber 4 and the liquid, discharge chamber 5. The nozzle plate 12 includes the plurality of nozzles 8 communicated with the plurality of ejection channels 6a, respectively.
The communication path 9 is provided in the vicinity of the ejection channel 6a farthest from a position to which the supply port 2 of the liquid supply chamber 4 is connected, that is, in the vicinity of each of both ends of the channel row 7 in the row direction. As illustrated in
As described above, the communication path 9 for bypassing the liquid from the liquid supply chamber 4 to the liquid discharge chamber 5 is provided in the vicinity of the channel 6 farthest from the position to which the supply port 2 is connected, and hence a liquid flow is generated in a region of the liquid supply chamber 4 separated from the supply port 2. As a result, the flow of liquid that crosses the opening portions of the slits 13 becomes large, and thus the air bubble is less liable to adhere to the opening portions of the slits 13. Further, even when the air bubble adheres to the opening portions of the slits 13, the adhering air bubble can be easily removed via the liquid discharge scanner 5 and the discharge port 3 by pumping liquid from the supply port 2 to carry the air bubble toward the communication path 9.
As illustrated in
When the communication path 9 is provided as described above, a liquid flow is generated in a region of the liquid supply chamber 4 separated from the supply port 2. As a result, the flow of liquid that crosses the opening portions of the slits 13 becomes large, and thus the air bubble is less liable to adhere to the opening portions of the slits 13. Further, even when the air bubble adheres to the opening portions of the slits 13, the adhering air bubble can be easily removed via the liquid discharge chamber 5 and the discharge port 3 by pumping liquid from the supply port 2 so carry the air bubble toward the communication path 9.
As illustrated in
In the above-mentioned embodiments, there is described a case where one channel row 7 is formed in the actuator substrate 10, but the present invention is not limited thereto. The present invention also encompasses a case where, in the liquid jet head 1 having a plurality of channel rows 7 formed therein, the communication path 9 for bypassing the liquid from the liquid supply chamber 4 to the liquid discharge chamber 5 is formed in the vicinity of the ejection channel 6a farthest from the position of the supply port 2.
As illustrated in
The flow path member 14 includes recessed portions (not shown) opened in the surface on the cover plate 11 side at positions corresponding to the liquid supply chamber 4 and the liquid discharge chamber 5 of the cover plate 11, and includes the supply port 2 communicated with the liquid supply chamber 4 and the discharge port 3 communicated with the liquid discharge chamber 5, which are formed on the surface on a side opposite to the cover plate 11.
A flexible substrate 21 is bonded en the exposed upper surface of the actuator substrate 10. A large number of wiring electrodes (not shown) are formed on the flexible substrate 21, and are electrically connected to the electrode terminals (not shown) formed on the exposed upper surface of the actuator substrate 10. The flexible substrate 11 includes, on its surface, a driver IC 28 as a drive circuit and a connector 29. The driver IC 28 generates a drive signal for driving the channel 6 (not shown) baaed on a signal input from the connector 29, and supplies the generated drive signal to the drive electrode (not shown) via the electrode terminal (not shown).
A base 30 houses the laminate of the nozzle plate 12, the actuator substrate 10, the cover plate 11, and the flow path member 14. A liquid jetting surface of the nozzle plate 12 is exposed at a lower surface of the base 30. The flexible substrate 21 is pulled outside from a side surface of the base 30, and is fixed to an outer surface of the base 30. The base 30 includes two through holes in an upper surface thereof. A supply tubs 31a for liquid supply is connected to the supply port 2 while passing through one through hole, and a discharge tube 31b for liquid discharge is connected to the discharge port 3 while passing through the other through hole.
The flow path member 14 is provided so as to supply liquid from an upper side and discharge the liquid to the upper side. Further, the driver IC 28 is mounted on the flexible substrate 21, and the flexible substrate 21 is bent to be provided upright in a z direction. The flexible substrate 21 is bonded to the upper surface of the actuator substrate 10 on the side opposite to the liquid ejection surface, and hence a space around the wiring can be sufficiently secured. Further, the driver IC 28 and the actuator substrate 10 generate heat when being driven, but the heat is transferred to the liquid flowing inside via the base 30 and the flow path member 14. That is, with use of recording liquid for a recording medium as a cooling medium, the heat generated inside can be efficiently dissipated outside. Therefore, the driver IC 28 and the actuator substrate 10 can be prevented from being lowered in driving ability due to overheating. Further, because the liquid circulates inside the groove and the communication path 9 is formed, even when an air bubble is mixed, the air bubble can be rapidly discharged to the outside. Thus, the liquid is not wasted, and it is also possible to suppress wasteful consumption of the recording medium due to recording failure. In this manner, it is possible to provide the liquid jet head 1 having high reliability.
(Liquid Jet Apparatus)
The liquid jet apparatus 50 includes a pair of conveyance means 41 and 42 for conveying a recording medium 44 such as paper in a main scanning direction, the liquid jet heads 1 and 1′ for ejecting liquid toward the recording medium 44, a carriage unit 43 tor mounting thereon the liquid jet heads 1 and 1′, the liquid pumps 33 and 33′ for pressurizing liquid stored in the liquid tanks 34 and 34′ into the flow path portions 35 and 35′ for circulation, and the moving mechanism 40 for causing the liquid jet heads 1 and 1′ to scan in a sub-scanning direction which is orthogonal to the main scanning direction. A control portion (not shown) controls and drives the liquid jet heads 1 and 1′, the moving mechanism 40, and the conveyance means 41 and 42.
Each of the pair of conveyance means 41 and 42 includes a grid roller and a pinch roller which extend in the sub-scanning direction and which rotate with roller surfaces thereof being in contact with each other. A motor (not shown) axially rotates the grid rollers and the pinch rollers to convey in the main scanning direction the recording medium 44 sandwiched therebetween. The moving mechanism 40 includes a pair of guide rails 36 and 37 which extend in the sub-scanning direction, the carriage unit 43 which is slidable along the pair of guide rails 36 and 37, an endless belt 38 which is coupled to the carriage unit 43 for moving the carriage unit 43 in the sub-scanning direction, and a motor 39 for rotating the endless belt 39 via a pulley (not shown).
The carriage unit 43 has the plurality of liquid jet heads 1 and 1′ mounted thereon for ejecting, for example, four kinds of liquid droplets: yellow; magenta; cyan; and black. The liquid tanks 34 and 34′ store liquid of corresponding colors, and circulate the liquid via the liquid pumps 33 and 33′ and the flow path portions 35 and 35′ to the liquid jet heads 1 and 1′. The respective liquid get heads 1 and 1′ eject liquid droplets of the respective colors in accordance with a drive signal. Through control of ejection timings of liquid from the liquid jet heads 1 and 1′, rotation of the motor 39 for driving the carriage unit 43, and conveyance speed of the recording medium 44, an arbitrary pattern may be recorded on the recording medium 44.
First, as illustrated in
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First, as illustrated in
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Number | Date | Country | Kind |
---|---|---|---|
2011-276297 | Dec 2011 | JP | national |
2012-217983 | Sep 2012 | JP | national |