Discharge head, discharge unit, and device for discharging liquid

Abstract

To prevent continuous discharge from being caused even if an abnormality occurs in a piezoelectric element.SOLUTION: A discharge module 100 of a discharge head 1 includes: a nozzle plate 101 formed with nozzles 111 for discharging a liquid; a passage 112 which communicates with the nozzles 111 and to which the compressed liquid is supplied; a needle-like valve body 113 which opens or closes the nozzles 111; and a piezoelectric element 114 which drives the valve body 113. The valve body 113 is driven in a direction such that the nozzles 111 are opened when a voltage is applied to the piezoelectric element 114. The discharge module 100 further includes a holding plate spring 116 serving as first biasing means, which biases the valve body 113 in the direction such that the nozzles 111 are opened, in parallel with the piezoelectric element 114.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a discharge head, a discharge unit, and an apparatus for discharging liquid. [Background technology]

[0002] 2. Description of the Related Art As an ejection head for ejecting liquid, there is a type in which pressurized liquid is supplied to a liquid chamber to which a nozzle is connected, and liquid is ejected from the nozzle by driving a valve that opens and closes the nozzle.

[0003] Conventionally, there is known a liquid ejection device which includes a storage chamber which is connected to an ejection port and which contains a liquid, and an ejection mechanism which ejects the liquid in the storage chamber from the ejection port, the ejection mechanism including a valve body which reciprocates within the storage chamber between a first position away from the ejection port and a second position which contacts the periphery of the ejection port and blocks the ejection port, and a drive unit which includes a piezoelectric element and a biasing means which apply a driving force to the valve body for the reciprocating movement, and which moves the valve body from the first position to the second position to push out and eject the liquid in the storage chamber to the ejection port (Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2017-164703 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, the configuration disclosed in Patent Document 1 has a problem in that if an abnormality occurs in the piezoelectric element, the intended liquid ejection cannot be performed, resulting in a decrease in image quality.

[0006] The present invention has been made in view of the above problems, and has an object to perform intended liquid ejection and prevent degradation of image quality even when an abnormality occurs in a piezoelectric element. [Means for solving the problem]

[0007] In order to solve the above problems, the ejection head according to claim 1 of the present invention comprises: A nozzle for discharging a liquid; A valve body that opens and closes the nozzle; A piezoelectric element that drives the valve body, the valve body is driven in a direction in which the nozzle opens when a voltage is applied to the piezoelectric element, a first biasing means arranged in parallel with the piezoelectric element for biasing the valve body in a direction in which the nozzle opens; 、 a second biasing means for biasing the valve body in a direction in which the nozzle is closed, the second biasing means being connected in series with the piezoelectric element; Is The composition was as follows. Effect of the Invention

[0008] According to the present invention, even if an abnormality occurs in a piezoelectric element, it is possible to perform intended liquid ejection and prevent degradation of image quality. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is an external perspective view of a discharge head according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a cross-sectional explanatory view taken along cross section S1 in FIG. [Diagram 3] FIG. 2 is a cross-sectional explanatory view of one ejection module of the ejection head. [Figure 4] FIG. 2 is an enlarged cross-sectional view illustrating a main portion of the discharge module. [Diagram 5] FIG. 4 is an enlarged explanatory view of a holding member of the discharge module. [Figure 6] 11 is an enlarged cross-sectional view illustrating a main portion of a discharge module of a discharge head according to a second embodiment of the present invention. FIG. [Figure 7] FIG. 11 is an enlarged cross-sectional view illustrating a main part of a discharge module of a discharge head according to a third embodiment of the present invention. [Figure 8] FIG. 11 is an enlarged cross-sectional view illustrating a main part of a discharge module of a discharge head according to a fourth embodiment of the present invention. [Figure 9]FIG. 13 is a cross-sectional view illustrating a discharge head according to a fifth embodiment of the present invention. [Figure 10] FIG. 2 is a cross-sectional explanatory view of one ejection module of the ejection head. [Figure 11] FIG. 13 is an enlarged explanatory view of a holding member of a discharge module according to a sixth embodiment of the present invention. [Figure 12] FIG. 13 is an enlarged explanatory view of a holding member of a discharge module according to a seventh embodiment of the present invention. [Figure 13] FIG. 13 is an enlarged explanatory view of a holding member of a discharge module according to an eighth embodiment of the present invention. [Figure 14] FIG. 13 is an explanatory diagram for explaining printing of an aircraft as a print target by a device for discharging liquid according to a ninth embodiment of the present invention. [Figure 15] FIG. 2 is a perspective view of the liquid ejecting device. [Figure 16] FIG. 23 is a perspective view of a liquid ejecting device according to a tenth embodiment of the present invention. [Figure 17] FIG. 2 is a perspective view of a drive unit of the device. [Figure 18] FIG. 23 is a plan view illustrating a main part of a device for discharging liquid according to an eleventh embodiment of the present invention. [Figure 19] FIG. [Figure 20] FIG. 13 is a plan view illustrating a main portion of another example of the discharge unit. [Figure 21] FIG. 13 is a front view illustrating still another example of the discharge unit. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. A first embodiment of the present invention will be described with reference to Figs. 1 to 5. Fig. 1 is an explanatory perspective view of the appearance of a discharge head according to the embodiment, and Fig. 2 is an explanatory cross-sectional view taken along section S1 in Fig. 1. Fig. 3 is an explanatory cross-sectional view of one discharge module of the discharge head, and Fig. 4 is an enlarged cross-sectional view of a main part of the discharge module. Fig. 5 is an enlarged explanatory view of a holding member of the discharge module.

[0011] The ejection head 1 has a plurality of ejection modules 100 arranged in one or more rows inside a housing 10. Pressurized liquid is supplied from the outside to each ejection module 100 via a supply port 11, and liquid that is not ejected is collected to the outside from a collection port 12. The housing 10 is also provided with a connector 2.

[0012] The ejection module 100 includes a nozzle plate 101 in which nozzles 111 for ejecting liquid are formed, a flow path 112 to which the nozzles 111 are connected and through which pressurized liquid is supplied, a needle-shaped valve body 113 for opening and closing the nozzles 111, and a piezoelectric element 114 for driving the valve body 113.

[0013] The nozzle plate 101 and the housing 10 are joined together. The flow path 112 is a common flow path for the multiple ejection modules 100 formed in the housing 10, and as described above, pressurized liquid is supplied through the supply port 11 and the liquid is recovered from the recovery port 12.

[0014] An elastic body 113a is provided at the tip of the valve body 113, which reliably closes the nozzle 111 when pressed against the nozzle plate 101. A bearing portion 121 is provided between the valve body 113 and the housing 10, and a seal member 122 such as an O-ring is provided between the bearing portion 121 and the valve body 113.

[0015] The piezoelectric element 114 is accommodated in a piezoelectric element accommodating space 123 of the housing 10. The piezoelectric element 114 is held in a central space 115a of a holding member 115 which also serves as a first biasing means. The piezoelectric element 114 and the valve body 113 are coaxially connected via a tip portion 115b of the holding member 115.

[0016] The holding member 115 has a central space 115a for accommodating the piezoelectric element 114, a tip end 115b side is connected to the valve body 113, and a rear end 115c side is fixed by a piezoelectric element fixing shaft 124 attached to the housing 10.

[0017] The holding member 115 has a holding leaf spring 116 as a first biasing means. The holding leaf spring 116 has elastically deformable spring portions 116a, 116b at both ends in the longitudinal direction corresponding to the expansion and contraction direction of the piezoelectric element 114. The spring portion 116a is located on the side of the tip portion 115b to which the valve body 113 is attached, and the spring portion 116b is located on the side of the rear end portion 115c opposite the side of the tip portion 115b to which the valve body 113 is attached.

[0018] The spring parts 116a and 116b have a spring function by providing slits 115d alternately in the short direction perpendicular to the long direction and leaving them in a crank shape. In this embodiment, the spring constants of the spring parts 116a and 116b are approximately the same (including being the same).

[0019] Here, the length of central space 115a of holding member 115 (the axial length of valve body 113) is set shorter than the length of piezoelectric element 114. Therefore, when piezoelectric element 114 is fitted into central space 115a of holding member 115, spring portions 116a and 116b of holding leaf spring 116 are in an extended state.

[0020] As a result, when the piezoelectric element 114 contracts in the direction of the arrow a in FIG. 4, the retaining leaf spring 116 also contracts in the direction of the arrow b, exerting a biasing force on the valve element 113 that pulls the valve element 113 in the direction in which the nozzle 111 opens.

[0021] Here, the piezoelectric element 114 operates in the D31 mode when a voltage is applied by the voltage application means 200, and drives the valve body 113 in the direction to open the nozzle 111. In other words, when a voltage is applied to the piezoelectric element 114, the valve body 113 is driven in the direction to open the nozzle 111.

[0022] Therefore, when no voltage is applied to the piezoelectric element 114, the valve body 113 closes the nozzle 111, so that no liquid is discharged from the nozzle 111 even if pressurized liquid is supplied to the flow path 112.

[0023] When a voltage is applied to the piezoelectric element 114, the piezoelectric element 114 contracts and pulls the valve body 113 via the holding member 115, causing the valve body 113 to move away from the nozzle 111 and opening the nozzle 111. As a result, the pressurized liquid supplied to the flow path 112 is discharged from the nozzle 111.

[0024] Next, the effects of this embodiment will be described.

[0025] First, as a comparative example, a case will be described in which a piezoelectric element that drives the valve element 113 operates in the D33 mode in which the piezoelectric element expands in a direction that closes the valve element 113 when a voltage is applied thereto.

[0026] When the piezoelectric element operates in D33 mode, the valve body 113 is pressed against the nozzle 111 to close it while a voltage is applied. Then, when liquid is to be ejected, the application of voltage to the piezoelectric element is stopped or the voltage is reduced, and the valve body 113 is moved in the opening direction to open the nozzle 111.

[0027] The D33 mode of the piezoelectric element has the advantage of being highly responsive and having a large amount of displacement, and the responsiveness of the opening and closing operation of the valve body 113 is high, and the variation in the droplet speed and droplet volume of the liquid ejected from the nozzle 111 can be reduced.

[0028] However, if the piezoelectric element experiences functional degradation due to migration or the like and is no longer able to maintain its extended state even when voltage is applied, the valve body 113 moves to the open position, opening the nozzle 11, and pressurized liquid is supplied to the flow path 112, resulting in a constant ejection state.

[0029] In contrast to this, in this embodiment, the piezoelectric element 114 is configured to operate in the D31 mode, so that the valve body 113 is held in a position that closes the nozzle 111 when no voltage is applied.

[0030] When a voltage is applied to the piezoelectric element 114 , the piezoelectric element 114 contracts, the valve body 113 opens, and the liquid is discharged from the nozzle 111 .

[0031] Therefore, even if the function of the piezoelectric element 114 deteriorates due to migration or the like, the valve body 113 will not move to a position that opens the nozzle 111, and therefore the ink will not be constantly discharged.

[0032] Here, when the piezoelectric element 114 is operated in the D31 mode, the response and displacement are lower than when it is operated in the D33 mode, so that the opening and closing response of the valve body 113 decreases, and there is a risk of the ejection characteristics varying more.

[0033] Therefore, in this embodiment, the piezoelectric element 114 is held by a holding member 115 having a first biasing means (holding leaf spring 116) in parallel with the piezoelectric element 114. In other words, a first biasing means is provided in parallel with the piezoelectric element 114 for biasing the valve body 113 in the direction in which the nozzle 111 opens. .

[0034] With this, when a voltage is applied to the piezoelectric element 114 to contract the piezoelectric element 114 and move the valve body 113 in the direction in which the nozzle 111 opens, the movement of the valve body 113 to the open position is assisted by the contraction of the retaining leaf spring 116.

[0035] Therefore, the force that moves the valve element 113 is increased, the responsiveness of the opening movement of the nozzle 111 by the valve element 113 is improved, and the variation in the ejection characteristics is reduced.

[0036] In contrast, when a biasing means such as a spiral spring is arranged in series with the piezoelectric element 114, the movement of the biasing means becomes independent of the movement of the piezoelectric element, which causes the inconvenience that vibrations occur in a direction that inhibits the movement of the piezoelectric element when the piezoelectric element vibrates freely.

[0037] In this embodiment, the piezoelectric element and the first biasing means are parallel, and the spring force (biasing force) is generated depending on the shape of the piezoelectric element, so that the movement (displacement) of the piezoelectric element and the biasing force can be perfectly synchronized, thereby providing assistance.

[0038] Next, a second embodiment of the present invention will be described with reference to Fig. 6. Fig. 6 is an enlarged cross-sectional explanatory view of a main part of a discharge module of a discharge head according to the second embodiment.

[0039] In this embodiment, a compression spring 117, which is a second biasing means, is disposed between the tip portion 115b of the holding member 115 and the shaft portion 113b of the valve body 113. Since the rear end portion 115c side of the holding member 115 is fixed, the biasing force of the compression spring 117 acts on the valve body 113 in a direction to close the nozzle 111.

[0040] As a result, when the application of voltage to the piezoelectric element 114 is stopped and the valve body 113 moves in the direction to close the nozzle 111, the biasing force of the compression spring 117 assists the movement of the valve body 113 to the closed position (a position that blocks the nozzle 111).

[0041] Therefore, the force that moves the valve element 113 is increased, the responsiveness of the movement of the valve element 113 to the closed position is improved, and the variation in the discharge characteristics is reduced.

[0042] Next, a third embodiment of the present invention will be described with reference to Fig. 7. Fig. 7 is an enlarged cross-sectional explanatory view of a main part of a discharge module of a discharge head according to the third embodiment.

[0043] In this embodiment, a displacement plate 118 is provided which separates the piezoelectric element accommodating space 123 in the housing 10 from a space 125 on the opposite side of the flow path 112 of the bearing portion 121. The displacement plate 118 is disposed between the holding member 115 and the valve body 113, and is displaceable in response to the movements of the valve body 113 and the holding member 115.

[0044] With this configuration, even if the pressurized liquid supplied to the flow path 112 leaks to the piezoelectric element 114 side through the gap between the valve body 113 and the bearing portion 121 due to a sealing failure of the sealing member 122, the liquid is prevented from entering the piezoelectric element accommodating space 123.

[0045] This can prevent the leaked liquid from adhering to the piezoelectric element 114 and causing the piezoelectric element 114 to malfunction.

[0046] Next, a fourth embodiment of the present invention will be described with reference to Fig. 8. Fig. 8 is an enlarged cross-sectional explanatory view of a main part of a discharge module of a discharge head according to the fourth embodiment.

[0047] In this embodiment, a plurality of discharge modules 100 are arranged in a common casing that is composed of a housing 10, a frame member 20, and a base member 21. The housing 10 and the frame member 20 are connected via a displacement plate 118, and the base member 21 is attached to an opening of the frame member 20.

[0048] The ejection module 100 includes a nozzle plate 101 having nozzles 111 formed therein for ejecting liquid, a flow path 112 for supplying pressurized liquid to the nozzles 111, a needle-shaped valve body 113 for opening and closing the nozzles 111, and a piezoelectric element 134 for driving the valve body 113.

[0049] The nozzle plate 101 and the housing 10 are joined together. The flow passage 112 is a flow passage common to the multiple ejection modules 100 formed in the housing 10.

[0050] An elastic body 113a is provided at the tip of the valve body 113, which reliably closes the nozzle 111 when pressed against the nozzle plate 101. A bearing portion 121 is provided between the valve body 113 and the housing 10, and a seal member 122 such as an O-ring is provided between the bearing portion 121 and the valve body 113.

[0051] The piezoelectric element 134 is accommodated in a piezoelectric element accommodating space 123 provided in the frame member 20. The piezoelectric element 134 is held in a central space 115a of a holding member 115 which also serves as a first biasing means. The piezoelectric element 134 and the valve body 113 are coaxially connected via a tip portion 115b of the holding member 115.

[0052] The holding member 115 has a central space 115 a for accommodating the piezoelectric element 134 , and is connected to the valve body 113 at its tip end 115 b side.

[0053] The holding member 115 has a holding leaf spring 116 as a first biasing means. The holding leaf spring 116 has elastically deformable spring portions 116a and 116b at both ends in the longitudinal direction, which corresponds to the direction in which the piezoelectric element 114 expands and contracts, similar to the first embodiment.

[0054] Here, the length of central space 115a of holding member 115 (the axial length of valve body 113) is set shorter than the length of piezoelectric element 134. Therefore, when piezoelectric element 134 is fitted into central space 115a of holding member 115, spring portions 116a and 116b of holding leaf spring 116 are in an extended state.

[0055] As a result, when the piezoelectric element 134 contracts, the retaining leaf spring 116 also contracts, and a biasing force acts on the valve element 113 to pull the valve element 113 in the direction in which the nozzle 111 opens.

[0056] Here, when a voltage is applied from the voltage application means 201, the piezoelectric element 134 operates in the D33 mode and drives the valve body 113 in a direction to close the nozzle 111. In other words, when a voltage is applied to the piezoelectric element 134, the valve body 113 is driven in a direction to close the nozzle 111.

[0057] Therefore, in this embodiment, a voltage is applied to the piezoelectric element 134 to expand the piezoelectric element 134, and the nozzle 111 is closed by the valve body 113. At this time, even if pressurized liquid is supplied to the flow path 112, no liquid is ejected from the nozzle 111.

[0058] Then, by stopping or lowering the voltage applied to the piezoelectric element 134, the piezoelectric element 134 contracts and pulls the valve body 113 via the holding member 115, so that the valve body 113 moves away from the nozzle 111 and opens the nozzle 111. As a result, the pressurized liquid supplied to the flow path 112 is discharged from the nozzle 111.

[0059] In this discharge module 100, a piezoelectric element 144 is disposed between the piezoelectric element 134 and the base member 21 via a holding member 115 as a means for displacing the piezoelectric element 134 and the valve body 113 in the direction in which the nozzle 111 closes.

[0060] When the piezoelectric element 134 experiences functional degradation due to migration or the like and is no longer able to maintain the expanded state even when a voltage is applied, a voltage is applied from a voltage application means 202 to the piezoelectric element 144 to expand the piezoelectric element 144.

[0061] As a result, the piezoelectric element 134 moves together with the valve body 113 via the holding member 115 in the direction of closing the nozzle 111, and the nozzle 111 is closed by the valve body 113, preventing the nozzle from being constantly ejected.

[0062] In this manner, in this embodiment, the piezoelectric element 134 is operated in the D33 mode to obtain high responsiveness and ejection characteristics, while preventing the piezoelectric element 134 from being in a constant ejection state.

[0063] The means for displacing the piezoelectric element 134 and the valve body 113 in the direction in which the valve body 113 closes is not limited to the piezoelectric element 144, and an actuator such as a solenoid may also be used.

[0064] In this embodiment, as described in the first to third embodiments, in the normal operating state, assistance can be provided by the holding leaf spring 116 (first biasing means) and the compression spring 117 (second biasing means). This can further improve responsiveness. Also, since the piezoelectric element and the first biasing means are parallel, a spring force (biasing force) is generated depending on the shape of the piezoelectric element, so that the movement (displacement) of the piezoelectric element and the biasing force can be completely synchronized, enabling assistance.

[0065] Next, a fifth embodiment of the present invention will be described with reference to Figures 9 and 10. Figure 9 is a cross-sectional explanatory view of a discharge head according to this embodiment, and Figure 10 is a cross-sectional explanatory view of one discharge module of the discharge head.

[0066] The ejection head 1 has a plurality of ejection modules 100 arranged in one or more rows within a housing 10 and a flow path member 102. Pressurized liquid is supplied from the outside to each ejection module 100 via a supply port 11, and liquid that is not ejected is recovered to the outside from a recovery port 12. In addition, a connector 2 is provided on the housing 10.

[0067] The ejection module 100 includes a nozzle plate 101 in which a nozzle 111 for ejecting liquid is formed, a flow path member 102 that forms a flow path 112 that supplies pressurized liquid to the nozzle 111, a needle-shaped valve body 113 that opens and closes the nozzle 111, and a piezoelectric element 114 that drives the valve body 113.

[0068] The nozzle plate 101 and the flow path member 102 are joined together. The flow path 112 is a flow path common to the multiple ejection modules 100 formed in the flow path member 102, and as described above, pressurized liquid is supplied through the supply port 11 and the liquid is recovered from the recovery port 12.

[0069] An elastic body 113 a is provided at the tip of the valve body 113 , which reliably closes the nozzle 111 when pressed against the nozzle plate 101 .

[0070] A plain bearing 127 is provided between the valve body 113 and the housing 10 as a guide member (guide member) that guides the movement of the valve body 113. By guiding the movement of the valve body 113 with the plain bearing 127, it is possible to suppress deviation of the central axes of the valve body 113 and the nozzle 111, and to reduce discharge bending.

[0071] A seal member 122 is provided between the valve body 113 and the flow path member 102 .

[0072] The piezoelectric element 114 is accommodated in a piezoelectric element accommodating space 123 of the housing 10. The piezoelectric element 114 is held in a central space 115a of a holding member 115 which also serves as a first biasing means. The piezoelectric element 114 and the valve body 113 are coaxially connected via a tip portion 115b of the holding member 115.

[0073] The holding member 115 has a central space 115a for accommodating the piezoelectric element 114, a tip end 115b side is connected to the valve body 113, and a rear end 115c side is fixed by a piezoelectric element fixing shaft 124 attached to the housing 10.

[0074] The holding member 115 has a holding leaf spring 116 as a first biasing means. In this embodiment, the holding leaf spring 116 has a spring portion 116a that is elastically deformable only on one end side (the side where the valve body 113 is attached) in the longitudinal direction corresponding to the expansion and contraction direction of the piezoelectric element 114.

[0075] Here, the length of central space 115a of holding member 115 (the axial length of valve body 113) is set shorter than the length of piezoelectric element 114. Therefore, when piezoelectric element 114 is fitted into central space 115a of holding member 115, spring portion 116a of holding leaf spring 116 is in an extended state.

[0076] As a result, when the piezoelectric element 114 contracts, the retaining leaf spring 116 also contracts, and a biasing force acts on the valve body 113 in a direction that pulls the valve body 113 (a direction that moves the valve body 113 away from the nozzle 111).

[0077] Here, the piezoelectric element 114 operates in a D31 mode in which it contracts in a direction that opens the valve body 113 when a voltage is applied.

[0078] Therefore, when no voltage is applied to the piezoelectric element 114, the valve body 113 closes the nozzle 111, so that no liquid is discharged from the nozzle 111 even if pressurized liquid is supplied to the flow path 112.

[0079] When a voltage is applied to the piezoelectric element 114, the piezoelectric element 114 contracts and pulls the valve body 113 via the holding member 115, causing the valve body 113 to move away from the nozzle 111 and opening the nozzle 111. As a result, the pressurized liquid supplied to the flow path 112 is discharged from the nozzle 111.

[0080] Furthermore, an elastic member 128 such as an O-ring that seals between the valve body 113 and the housing 10 is disposed between the sliding bearing 127 and the tip end portion of the piezoelectric element 114 (tip end portion 115b of the holding member 115). Also, an elastic member 129 such as an O-ring that seals between the piezoelectric element fixing shaft 124 and the housing 10 is disposed.

[0081] This blocks the piezoelectric element housing space 123 housing the piezoelectric element 114 from the outside air, and protects the piezoelectric element 114 from moisture.

[0082] Next, a sixth embodiment of the present invention will be described with reference to Fig. 11. Fig. 11 is an enlarged explanatory view of a holding member of a discharge module according to the sixth embodiment.

[0083] In this embodiment, spring portions 116a and 116b provided at both longitudinal ends of retaining leaf spring 116 have different spring constants. Here, the number of slits 115d in spring portion 116a on the side where valve body 113 is attached is set to four (two on each side), and the number of slits 115d in spring portion 116b on the opposite side to the side where valve body 113 is attached is set to six (three on each side), thereby making the spring constants different.

[0084] In this way, by making the spring constants of spring portions 116a and 116b provided at both ends of holding leaf spring 116 different, the displacement speed of piezoelectric element 114 can be made different on the expansion side and the contraction side.

[0085] For example, the contraction speed is increased by increasing the number of springs on the valve body 113 side, and the expansion speed is increased by increasing the number of springs on the opposite side to the valve body 113.

[0086] Next, a seventh embodiment of the present invention will be described with reference to Fig. 12. Fig. 12 is an enlarged explanatory view of a holding member of a discharge module according to the seventh embodiment.

[0087] In this embodiment, the holding plate spring 116 is provided with a spring portion 116a and a spring portion 116b at both ends in the longitudinal direction, and a spring portion 116c at the center in the longitudinal direction. The configuration of the spring portion 116c is similar to that of the spring portions 116a and 116b.

[0088] In this way, by providing spring portions 116a to 116c at both ends and the center of holding leaf spring 116, holding leaf spring 116 can be displaced as a whole, and the displacement force of piezoelectric element 114 can be transmitted to valve body 113 without waste.

[0089] Next, an eighth embodiment of the present invention will be described with reference to Fig. 13. Fig. 13 is an enlarged explanatory view of a holding member of a discharge module according to the same embodiment.

[0090] In this embodiment, spring portions 116a and 116b provided at both longitudinal ends of retaining leaf spring 116 have different spring constants. Here, the spring constants are made different by making the spacing da of slits 115d of spring portion 116a on the side where valve body 113 is attached wider than the spacing db of slits 115d of spring portion 116b on the opposite side to the side where valve body 113 is attached.

[0091] In this way, by making the spring constants of spring portions 116a and 116b provided at both ends of holding leaf spring 116 different, the displacement speed of piezoelectric element 114 can be made different on the expansion side and the contraction side.

[0092] Next, a ninth embodiment of the present invention will be described with reference to Fig. 14 and Fig. 15. Fig. 14 is an explanatory diagram for explaining printing of an airplane as a print target using the device for ejecting liquid according to the embodiment, and Fig. 15 is a perspective explanatory diagram of the device for ejecting liquid.

[0093] The liquid ejecting device 500 includes a linear rail 504 that moves a carriage, which is a moving body carrying an ejection unit 501 including the ejection head 1, back and forth in a straight line, and an articulated robot 505 that moves the linear rail 504 to a predetermined position as appropriate and holds it in that position.

[0094] The articulated robot 505 is equipped with a robot arm 505a that has multiple joints that enable it to move freely like a human arm, and the tip of the robot arm 505a can be moved freely and positioned accurately.

[0095] As the articulated robot 505, for example, a six-axis controlled industrial robot having six axes, i.e., six joints, can be used. With a six-axis articulated robot, by teaching information regarding the operation in advance, it is possible to very accurately and quickly make the linear rail 504 face a predetermined position on the printing target 700 (aircraft). The robot 505 is not limited to a six-axis robot, and an articulated robot having an appropriate number of axes, such as five axes or seven axes, can be used.

[0096] A fork-shaped support member 524 that branches into two branches is provided on the robot arm 505a of this robot 505, and a vertical linear rail 523a is attached to the tip of the left branch 524a of this support member 524, and a vertical linear rail 523b is attached to the tip of the right branch 524b so that they are parallel to each other.

[0097] The discharge unit 501 is movably supported by a linear rail 504, the ends of which are supported by being bridged across two vertical linear rails 523a and 523b, respectively.

[0098] The discharge unit 501 includes a plurality of discharge heads 1 that discharge liquid of each color, for example, black, cyan, magenta, yellow, and white, or a discharge head 1 having a plurality of nozzle rows. Liquid of each color is supplied under pressure from a liquid tank 530 to each discharge head 1 or each nozzle row of the discharge head 1 of the discharge unit 501.

[0099] In this liquid ejection device 500, a robot 505 moves a linear rail 504 to a position facing a required printing area of ​​a print target 700. Then, while moving the ejection unit 501 along the linear rail 504 in accordance with print data, the piezoelectric element 114 (or the piezoelectric element 134) of each ejection module 100 of the ejection head 1 is driven to perform printing.

[0100] Then, when printing of one line is completed, the vertical linear rails 523a and 523b are driven to move the discharge head 1 of the discharge unit 501 from one line to the next line.

[0101] This operation can be repeated to print on the desired printing area of ​​the printing object 700.

[0102] Next, a tenth embodiment of the present invention will be described with reference to Figures 16 and 17. Figure 16 is a perspective explanatory view of a device for discharging liquid according to the same embodiment, and Figure 17 is a perspective explanatory view of a drive unit of the same device.

[0103] The liquid ejecting device 500 includes a movable frame unit 802 that is installed facing a printing target 700 having a curved surface, such as a vehicle bonnet. A movable unit 813 is attached to left and right frame members 810, 811 that constitute the frame unit 802 so as to span the frame members 810, 811 and be capable of ascending and descending in the vertical direction (Y direction).

[0104] The movable unit 813 is equipped with a drive unit 803 incorporating a motor arranged to be able to move back and forth in the horizontal direction (X direction) on the movable unit 813, and an ejection unit 501 attached to this drive unit 803 and ejecting liquid toward the printing target 700.

[0105] Also included is a controller 805 that controls the ejection of liquid from the ejection unit 501, the reciprocating movement of the drive unit 803, and the elevation of the movable unit 813, and an information processing device 806 such as a PC (personal computer) that issues instructions to the controller 805. A database section (DB section) 807 that records and saves information about the print target 700, such as its shape and size, is connected to the information processing device 806.

[0106] The frame unit 802 has upper, lower, left and right frame members 808, 809, 810, 811 formed by metal pillars or the like, and left and right leg members 812a, 812b attached horizontally and at right angles to both sides of the lower frame member 809 to enable the frame unit 802 to stand on its own.

[0107] A movable unit 813 that is bridged between the left and right frame members 810 and 811 is configured to be capable of ascending and descending while supporting the drive section 803 .

[0108] The printing target 700 is disposed perpendicular to the liquid ejection direction (Z direction), that is, facing a plane formed by the top, bottom, left and right frame members 808, 809, 810, and 811 of the frame unit 802.

[0109] In this case, the printing object 700 can be positioned at a predetermined position where printing is to be performed, for example, by suction-holding the back side of the printing area of ​​the printing object 700 with a chuck attached to the tip of the arm of an articulated arm robot. By using an articulated arm robot, it is possible to accurately position the printing object 700 at the printing position, and the posture of the printing object 700 can also be changed appropriately.

[0110] 17, the drive unit 803 is disposed so as to be capable of reciprocating in the horizontal direction (X direction) on the movable unit 813. The movable unit 813 is configured to include a rail 830 disposed horizontally so as to span the left and right frame members 810, 811 of the frame unit 802, a rack gear 831 disposed parallel to the rail 830, a linear guide 832 fitted onto a part of the rail 830 and moving while sliding, a pinion gear unit 833 connected to the linear guide 832 and meshing with the rack gear 831, a motor 834 with a reducer 836 that rotates and drives the pinion gear unit 833, and a rotary encoder 835 for detecting the print point position.

[0111] By driving the motor 834 (rotating forward or backward), the discharge unit 501 is moved rightward or leftward along the movable unit 813. The drive unit 803 functions as a drive mechanism for the X direction of the discharge unit 501. Note that limit switches 37a and 37b are attached to both sides of the housing of the reducer 836.

[0112] The discharge unit 501 includes a plurality of discharge heads 1 that discharge liquid of each color, for example, black, cyan, magenta, yellow, and white, or a discharge head 1 having a plurality of nozzle rows. Liquid of each color is supplied under pressure from a liquid tank to each discharge head 1 or each nozzle row of the discharge head 1 of the discharge unit 501.

[0113] In the liquid ejecting device 500, the movable unit 813 is moved in the Y direction and the ejection unit 501 is moved in the X direction to print a desired image on the printing object 700.

[0114] Next, an eleventh embodiment of the present invention will be described with reference to Figures 18 and 19. Figure 18 is a plan view of the essential parts of a device for discharging liquid according to this embodiment, and Figure 19 is a side view of the essential parts of the device.

[0115] The liquid ejecting device 500 is a serial type printing device, and a carriage 403 is reciprocated in the main scanning direction by a main scanning movement mechanism 493. The main scanning movement mechanism 493 includes a guide member 401, a main scanning motor 405, a timing belt 408, etc. The guide member 401 is hung between left and right side plates 491A and 491B to movably hold the carriage 403. The carriage 403 is reciprocated in the main scanning direction by the main scanning motor 405 via a timing belt 408 hung between a drive pulley 406 and a driven pulley 407.

[0116] A discharge unit 501 including a discharge head 1 according to the present invention is mounted on this carriage 403. The discharge head 1 of the discharge unit 501 discharges liquid of each color, for example, yellow (Y), cyan (C), magenta (M), and black (K).

[0117] This device 500 is equipped with a transport mechanism 495 for transporting the paper 410. The transport mechanism 495 includes a transport belt 412, which is a transport means, and a sub-scanning motor 416 for driving the transport belt 412.

[0118] The conveyor belt 412 attracts the paper 410 and conveys it to a position facing the discharge head 1. The conveyor belt 412 is an endless belt, and is stretched between a conveyor roller 413 and a tension roller 414. The paper can be attracted by electrostatic attraction or air suction.

[0119] The conveyor belt 412 moves in a circular motion in the sub-scanning direction as the conveyor rollers 413 are rotated by a sub-scanning motor 416 via a timing belt 417 and a timing pulley 418 .

[0120] Furthermore, a maintenance and recovery mechanism 420 for performing maintenance and recovery of the ejection head 1 is disposed on one side of the conveyor belt 412 on one side of the carriage 403 in the main scanning direction.

[0121] The maintenance and recovery mechanism 420 is composed of, for example, a cap member 421 that caps the nozzle surface (the surface on which the nozzles are formed) of the ejection head 1, a wiper member 422 that wipes the nozzle surface, and the like.

[0122] The main scanning movement mechanism 493, the maintenance and recovery mechanism 420, and the transport mechanism 495 are attached to a housing including side plates 491A and 491B and a back plate 491C.

[0123] In the liquid ejecting device 500 configured in this manner, the paper 410 is fed onto the conveyor belt 412 and adsorbed thereon, and the paper 410 is conveyed in the sub-scanning direction by the circular movement of the conveyor belt 412.

[0124] Therefore, by driving the ejection head 1 in response to an image signal while moving the carriage 403 in the main scanning direction, liquid is ejected onto the stationary paper 410 to form an image. do.

[0125] Next, another example of the discharge unit will be described with reference to Fig. 20. Fig. 20 is a plan view illustrating the main part of the unit.

[0126] Among the components constituting the device 500 that discharges the liquid, the discharge unit 501 is composed of a housing portion constituted by side plates 491A, 491B and a back plate 491C, a main scanning movement mechanism 493, a carriage 403, and a discharge head 1.

[0127] It should be noted that a discharge unit can also be configured by further attaching the above-mentioned maintenance and recovery mechanism 420 to, for example, the side plate 491B of this discharge unit 501.

[0128] Next, still another example of the discharge unit will be described with reference to Fig. 21. Fig. 21 is a front explanatory view of the unit.

[0129] The discharge unit 501 is composed of a discharge head 1 to which a flow path part 444 is attached, and a tube 456 connected to the flow path part 444 .

[0130] The flow path part 444 is disposed inside the cover 442. A connector 443 for electrically connecting with the discharge head 1 is provided on the upper part of the flow path part 444.

[0131] In the present application, the liquid to be ejected may have a viscosity and surface tension that allows it to be ejected from the head, and is not particularly limited, but it is preferable that the viscosity of the liquid is 30 mPa·s or less at room temperature and pressure, or by heating or cooling. More specifically, the liquid may be a solution, suspension, emulsion, etc., containing a solvent such as water or an organic solvent, a colorant such as a dye or pigment, a functionalizing material such as a polymerizable compound, a resin, or a surfactant, a biocompatible material such as DNA, amino acids, proteins, or calcium, an edible material such as a natural colorant, etc., and these can be used for applications such as inkjet ink, surface treatment liquid, a liquid for forming a component of an electronic element or a light-emitting element, an electronic circuit resist pattern, a material liquid for three-dimensional modeling, etc.

[0132] Energy sources for ejecting liquid include piezoelectric actuators (laminated piezoelectric elements and thin-film piezoelectric elements), thermal actuators that use electrothermal conversion elements such as heating resistors, and electrostatic actuators consisting of a vibration plate and an opposing electrode.

[0133] The "ejection unit" is an integral part of an ejection head, which includes functional parts and mechanisms, and includes a collection of parts related to ejecting liquid. For example, the "ejection unit" includes a combination of an ejection head and at least one of the following components: a head tank, a carriage, a supply mechanism, a maintenance and recovery mechanism, a main scanning movement mechanism, and a liquid circulation device.

[0134] Here, integration includes, for example, the ejection head, the functional parts, and the mechanism being fixed to each other by fastening, bonding, engaging, etc., and one being held movably relative to the other. Also, the ejection head, the functional parts, and the mechanism may be configured to be detachable from each other.

[0135] For example, there are ejection units in which the ejection head and the head tank are integrated together, and there are also ejection units in which the ejection head and the head tank are integrated together by being connected to each other by a tube, etc. Here, a unit including a filter can be added between the head tank and the ejection head of these ejection units.

[0136] Furthermore, there is a discharge unit in which the discharge head and the carriage are integrated.

[0137] In addition, there is a discharge unit in which the discharge head is movably held by a guide member constituting a part of the scanning movement mechanism, and the discharge head and the scanning movement mechanism are integrated together, and there is also a discharge unit in which the discharge head, the carriage, and the main scanning movement mechanism are integrated together.

[0138] In addition, there is a discharge unit in which a cap member, which is part of the maintenance and recovery mechanism, is fixed to a carriage on which the discharge head is attached, thereby integrating the discharge head, carriage, and maintenance and recovery mechanism.

[0139] In addition, there is a discharge unit in which a tube is connected to a discharge head having a head tank or a flow path component attached thereto, and the discharge head and a supply mechanism are integrated together. Liquid is supplied from a liquid storage source to the discharge head via this tube.

[0140] The main scanning movement mechanism includes the guide member alone, and the supply mechanism includes the tube alone and the loading unit alone.

[0141] "Liquid ejection device" includes devices that have an ejection head or an ejection unit and eject liquid by driving the ejection head. Liquid ejection devices include not only devices that can eject liquid onto objects to which the liquid can adhere, but also devices that eject liquid into air or liquid.

[0142] This "liquid ejecting device" can also include means for feeding, transporting, and discharging items onto which liquid can be attached, as well as pre-processing devices and post-processing devices.

[0143] For example, examples of "devices that eject liquid" include image forming devices that eject ink to form an image on paper, and three-dimensional modeling devices that eject modeling liquid onto a powder layer formed by layering powder in order to create a three-dimensional object (a three-dimensional model).

[0144] In addition, the term "liquid ejection device" is not limited to devices that use ejected liquid to visualize meaningful images such as letters and figures. For example, it also includes devices that form patterns that have no meaning in themselves and devices that create three-dimensional images.

[0145] The above-mentioned "object to which liquid can adhere" means an object to which liquid can adhere at least temporarily, and to which the liquid adheres and sticks, or to which the liquid adheres and penetrates, etc. Specific examples include media such as paper, recording paper, film, cloth, and other recording media, electronic boards, electronic components such as piezoelectric elements, powder layers, organ models, and test cells, and unless otherwise specified, includes all objects to which liquid can adhere.

[0146] The material of the above-mentioned "object to which liquid can adhere" may be any material to which liquid can adhere even temporarily, such as paper, thread, fiber, cloth, leather, metal, plastic, glass, wood, and ceramics.

[0147] In addition, the "liquid ejection device" may be a device in which the ejection head and the object to which the liquid can adhere move relatively, but is not limited to this. Specific examples include a serial type device in which the ejection head moves, a line type device in which the ejection head does not move, etc.

[0148] Other examples of "liquid ejecting devices" include a treatment liquid application device that ejects a treatment liquid onto paper to apply the treatment liquid to the surface of the paper for purposes such as modifying the surface of the paper, and an injection granulation device that ejects a composition liquid in which raw materials are dispersed through a nozzle to granulate fine particles of the raw materials.

[0149] In the present application, the terms image formation, recording, printing, imprinting, printing, modeling, and the like are all synonymous. [Explanation of symbols]

[0150] 1 Discharge head 10. Housing 20 Frame members 21 Base material 100 Dispensing Module 101 Nozzle plate 102 Flow path member 111 Nozzle 112 Liquid chamber 113 Valve body 114 Piezoelectric element 115 Retaining member 116 Retaining leaf spring (first biasing means) 117 Compression spring (second biasing means) 118 Displacement plate 123 Piezoelectric element housing space 200 to 202 Voltage application means 500 Liquid ejection device 501 Discharge unit 700 Printing objects

Claims

1. A nozzle for discharging a liquid; A valve body that opens and closes the nozzle; A piezoelectric element that drives the valve body, the valve body is driven in a direction in which the nozzle opens when a voltage is applied to the piezoelectric element, a first biasing means arranged in parallel with the piezoelectric element and biasing the valve body in a direction in which the nozzle opens, A second biasing means is provided in series with the piezoelectric element for biasing the valve body in a direction in which the nozzle is closed. A discharge head comprising:

2. A nozzle for discharging a liquid; A valve body that opens and closes the nozzle; A piezoelectric element that drives the valve body; a holding member for holding an end of the piezoelectric element on a side opposite to a side on which the valve body is provided; a means for displacing the piezoelectric element and the valve body via the holding member in a direction in which the nozzle is closed, The piezoelectric element drives the valve body in a direction to close the nozzle when a voltage is applied thereto. A discharge head comprising:

3. The means for displacing a nozzle disposed on the opposite side of the piezoelectric element from the nozzle; Including a piezoelectric element other than the piezoelectric element, 3. The ejection head according to claim 2.

4. A first biasing means is provided in parallel with the piezoelectric element for biasing the valve body in a direction in which the nozzle opens.

4. The ejection head according to claim 2 or 3.

5. A second biasing means is provided in series with the piezoelectric element for biasing the valve body in a direction in which the nozzle is closed.

4. The ejection head according to claim 2 or 3.

6. A guide member is provided to guide the movement of the valve body.

6. The ejection head according to claim 1,

7. A displacement plate is provided between the piezoelectric element and the valve body, the displacement plate being capable of being displaced in response to the movement of the valve body.

7. The ejection head according to claim 1,

8. a housing having a flow path communicating with the nozzle and a piezoelectric element accommodating space accommodating the piezoelectric element; The displacement plate separates the piezoelectric element accommodating space from the flow path.

8. The ejection head according to claim 7.

9. The first biasing means has at least elastically deformable spring portions at both ends in the expansion and contraction direction of the piezoelectric element.

5. The ejection head according to claim 1 or 4.

10. The first biasing means has a spring portion that is elastically deformable at the center in the direction of expansion and contraction of the piezoelectric element.

10. The ejection head according to claim 9.

11. The spring portions at both ends of the first biasing means have different spring constants.

11. The ejection head according to claim 9 or 10.

12. Equipped with the ejection head according to any one of claims 1 to 11 A discharge unit characterized by:

13. The ejection head according to any one of claims 1 to 11 or the ejection unit according to claim 12 is provided. A liquid ejection device comprising:

Images