Patent Grant
10864726
Embodiments of the present disclosure relate to a technique for ejecting liquid such as ink.
A liquid ejecting head that ejects a liquid such as ink out of a pressure compartment through a nozzle by operating a drive element such as a piezoelectric element is known. For example, a head disclosed in JP-A-2014-061695 has the following structure. A first pressure compartment, which is in communication with a first common passage, and a second pressure compartment, which is in communication with a second common passage, are arranged in series. Ink is supplied from an ink supply unit to the first common passage. Ink is discharged to an ink collection unit from the second common passage. There is a hole formed in a wall between the first pressure compartment and the second pressure compartment. This structure produces a circulating flow of ink (liquid) that is supplied from the first common passage, moves from the first pressure compartment to the second pressure compartment through the hole, and is discharged to the second common passage. In JP-A-2014-061695, a filter and a deaerator for removing air bubbles and foreign substances contained in the circulating ink are provided at a communication portion via which the first common passage and the second common passage are in communication with each other.
In JP-A-2014-061695, the wall is formed between the first pressure compartment and the second pressure compartment for the purpose of preventing a backflow of the ink from the second pressure compartment to the first pressure compartment during an operation for ejecting, from the nozzle, the ink that has moved into the second pressure compartment from the first pressure compartment. Moreover, since the second pressure compartment is in communication with the second common passage, a part of the ink in the second pressure compartment is discharged to the second common passage without being ejected from the nozzle. Therefore, if the structure disclosed in JP-A-2014-061695 is employed, it is difficult to discharge ink whose amount is greater than the capacity (volume) of either one of the first pressure compartment and the second pressure compartment.
A liquid ejecting head according to a preferred aspect (first aspect) of the present disclosure includes: a nozzle from which a liquid is ejected; a communication passage that is in communication with the nozzle; a first pressure compartment that is connected to the communication passage through a first passage; a second pressure compartment that is connected to the communication passage through a second passage; a common liquid chamber that communicates the first pressure compartment and the second pressure compartment with each other and retains the liquid that is to be ejected from the nozzle; a first drive element that changes pressure of the first pressure compartment; and a second drive element that changes pressure of the second pressure compartment.
The invention will be described with reference to the accompanying drawings, wherein like numbers reference like elements.
The liquid container 14 is an ink-tank-type cartridge formed of a box-shaped container detachably attached to the body of the liquid ejecting apparatus 10. The liquid container 14 is not limited to a box-shaped container. The liquid container 14 may be an ink-pack-type cartridge that is a bag-shaped container. An ink tank that can be replenished with ink may be used as the liquid container 14. The ink contained in the liquid container 14 may be black ink or color ink. The ink contained in the liquid container 14 is supplied (pressure-fed) to the liquid ejecting head 26 by a pump (not illustrated).
The control unit 20 includes, for example, a control device 202 such as a central processing unit (CPU) or a field programmable gate array (FPGA) and a storage device 203 such as semiconductor memory. For central control on each component of the liquid ejecting apparatus 10, the control device 202 runs control programs stored in the storage device 203. As illustrated in
The transport mechanism 22 transports the medium 12 in the Y direction under the control of the control unit 20. The liquid ejecting head 26 is mounted on the carriage 24, which has a shape like a box. Under the control of the control unit 20, the liquid ejecting head 26 ejects ink supplied from the liquid container 14 onto the medium 12. The control unit 20 reciprocates the carriage 24 in the X direction (which is an example of a first direction) orthogonal to the Y direction (which is an example of a second direction). Concurrently with the transportation of the medium 12 by the transport mechanism 22 and the repetitive reciprocating motion of the carriage 24, the liquid ejecting head 26 ejects ink onto the medium 12, thereby forming an image on the surface of the medium 12 in accordance with instructions. The liquid container 14 may be mounted in addition to the liquid ejecting head 26 on the carriage 24.
The liquid ejecting head 26 has an ejecting surface 260 (facing toward the medium 12). The ejecting surface 260 has a nozzle array. The nozzle array is a set of nozzles N arranged linearly in the Y direction. Ink supplied from the liquid container 14 is ejected from the nozzles N. The number of nozzles in the array, and the arrangement pattern of them, is not limited to the illustrated example. Two or more rows of nozzles may be arranged in the ejecting surface 260 of the liquid ejecting head 26. Zigzag arrangement or staggered arrangement, etc. may be adopted for such rows of nozzles. The direction perpendicular to the X-Y plane (i.e., plane parallel to the surface of the medium 12) is denoted as the Z direction.
The drive signal generation unit 40 generates a drive signal COM. The drive signal COM is a voltage signal that contains drive pulses (drive waveform) in a predetermined cycle. Specifically, for example, as illustrated in
As illustrated in
When ink is ejected in accordance with the print data G received by the control unit 20, the drive signal COM, which is generated by the drive signal generation unit 40 in accordance with the print data G, and a selection signal SI, which specifies whether or not to eject ink in accordance with the print data G, are supplied from the control unit 20 to the drive unit 262. For each of the plurality of ejectors 266, the drive unit 262 generates a drive signal V corresponding to the drive signal COM and the selection signal SI. Then, the drive unit 262 outputs the drive signals V to the plurality of ejectors 266 in parallel. Specifically, the drive unit 262 outputs the drive signal COM as the drive signal V to, among the plurality of ejectors 266, each ejector 266 for which the selection signal SI specifies ink ejection. The drive unit 262 outputs the reference potential VM as the drive signal V to, among the plurality of ejectors 266, each ejector 266 for which the selection signal SI specifies ink non-ejection.
As illustrated in
As illustrated in
As illustrated in
As illustrated in
In the example of the present embodiment, the pressure compartment substrate 72 and the diaphragm 73 are distinct from each other. However, the pressure compartment substrate 72 and the diaphragm 73 may be formed integrally. For example, it is possible to form the pressure compartment substrate 72 and the diaphragm 73 integrally by preparing a plate member that has a predetermined thickness and by selectively removing a part of the plate member in the thickness direction at areas corresponding to the openings 722a and 722b.
According to the above structure, the space between the diaphragm 73 and the passage substrate 71 inside the opening 722a functions as the first pressure compartment SA, and the space between the diaphragm 73 and the passage substrate 71 inside the opening 722b functions as the second pressure compartment SB.
An opening 712a for configuring the common liquid chamber SR is formed in the first substrate 71a. Of the two surfaces of the first substrate 71a, it is the second-substrate-side (71b) surface that has the opening 712a. The opening 712a formed in this +Z surface is closed by the second substrate 71b. An opening 712b formed in the −Z surface is in communication with the opening 712a.
The opening 712b formed in the pressure-compartment-substrate-side (72) surface of the first substrate 71a is in communication with an opening 724 of the pressure compartment substrate 72. Each of the openings 712a, 712b, and 724 is long in the Y direction. In a plan view, the width of the opening 712b in the X direction is narrower than the width of the opening 712a in the X direction, and the width of the opening 724 in the X direction is the same as the width of the opening 712b in the X direction. The meaning of “in a plan view” is: “as viewed in the Z direction”. The same applies hereinafter.
At the −Z surface of the pressure compartment substrate 72, the opening 724 is closed by a flexible membrane 725. According to the above structure, the space between the flexible membrane 725 and the second substrate 71b inside the openings 712a, 712b, and 724 functions as the common liquid chamber SR. The flexible membrane 725 is a film (compliance substrate) that has flexibility for absorbing pressure fluctuations of ink inside the common liquid chamber SR.
The first pressure compartment SA and the second pressure compartment SB are in communication with each other via the common liquid chamber SR of the present embodiment. Specifically, for each of the plurality of ejectors 266, the first branch passage DA and the second branch passage DB are formed in the first substrate 71a. The first branch passage DA is an individual passage branching off from the common liquid chamber SR for connecting the common liquid chamber SR to the first pressure compartment SA of each of the plurality of ejectors 266. The second branch passage DB is an individual passage branching off from the common liquid chamber SR for connecting the common liquid chamber SR to the second pressure compartment SB of each of the plurality of ejectors 266. The first pressure compartment SA becomes filled with ink supplied from the common liquid chamber SR through the first branch passage DA. The second pressure compartment SB becomes filled with ink supplied from the common liquid chamber SR through the second branch passage DB.
Inside the area of the opening 712a, the first branch passage DA is located at an area that is closer to the first pressure compartment SA than the opening 712b is; more specifically, the first branch passage DA overlaps with the first pressure compartment SA in a plan view. Inside the area of the opening 712a, the second branch passage DB is located at an area that is closer to the second pressure compartment SB than the opening 712b is; more specifically, the second branch passage DB overlaps with the second pressure compartment SB in a plan view. Because of this layout, it is possible to configure such that each of the first branch passages DA extends toward the negative side in the Z direction from the opening 712a and is connected to the first pressure compartment SA and such that each of the second branch passages DB extends toward the negative side in the Z direction from the opening 712a and is connected to the second pressure compartment SB.
As illustrated in
The passage 772C of the communication passage 772 is located at substantially the center of the liquid ejecting unit 264 in the X direction, and is located between the passage 772A and the passage 772B in a plan view. The passage 772A is in communication with the first passage EA and overlaps with the first pressure compartment SA in a plan view. The passage 772a is a narrowed passage that has a smaller sectional area than the passage 772A and connects the passage 772A to the passage 772C. The passage 772B is in communication with the second passage EB and overlaps with the second pressure compartment SB in a plan view. The passage 772b is a narrowed passage that has a smaller sectional area than the passage 772B and connects the passage 772B to the passage 772C. Since the passage 772a and the passage 772b are formed as narrowed passages, it is possible to increase the flow velocity of ink from the passage 772A and from the passage 772B toward the nozzle N. However, the sectional area of the passage 772a may be equal to the sectional area of the passage 772A, and the sectional area of the passage 772b may be equal to the sectional area of the passage 772B.
An opening 718a for configuring the first passage EA is formed in the passage substrate 71. In addition, an opening 718b for configuring the second passage EB is formed in the passage substrate 71. The opening 718a is located in the first structure portion P1. The opening 718a goes through the first substrate 71a and the second substrate 71b to connect the first pressure compartment SA to the communication passage 772. The opening 718b is located in the second structure portion P2. The opening 718b goes through the first substrate 71a and the second substrate 71b to connect the second pressure compartment SB to the communication passage 772.
The first passage EA is located on the negative side in the X direction with respect to the first pressure compartment SA. The first branch passage DA is located on the positive side in the X direction with respect to the first pressure compartment SA. The second passage EB is located on the positive side in the X direction with respect to the second pressure compartment SB. The second branch passage DB is located on the negative side in the X direction with respect to the second pressure compartment SB. The first passage EA and the first branch passage DA overlap with the first pressure compartment SA in a plan view. The second passage EB and the second branch passage DB overlap with the second pressure compartment SB in a plan view. This structure reduces the size of the liquid ejecting unit 264 in the X direction. Therefore, it is possible to reduce the size of the liquid ejecting head 26 in the X direction.
In the present embodiment, the first pressure compartment SA has a quadrangular shape (e.g., rectangle, square) in a plan view, and the passage 772A of the communication passage 772 also has a quadrangular shape in a plan view. However, the shape of the first pressure compartment SA and the passage 772A is not limited to the illustrated example. The shape in a plan view may be a parallelogram, an ellipse, a circle, or the like. In the present embodiment, the second pressure compartment SB has a quadrangular shape (e.g., rectangle, square) in a plan view, and the passage 772B of the communication passage 772 also has a quadrangular shape in a plan view. However, the shape of the second pressure compartment SB and the passage 772B is not limited to the illustrated example. The shape in a plan view may be a parallelogram, an ellipse, a circle, or the like.
In the present embodiment, the first branch passage DA and the first passage EA extend in the Z direction, and the second branch passage DB and the second passage EB extend in the Z direction. However, the passage may be inclined with respect to the Z direction. In the present embodiment, each of the first branch passage DA and the first passage EA overlaps with the first pressure compartment SA in a plan view. However, the passage may have a portion that does not overlap with the first pressure compartment SA in a plan view. In the present embodiment, each of the second branch passage DB and the second passage EB overlaps with the second pressure compartment SB in a plan view. However, the passage may have a portion that does not overlap with the second pressure compartment SB in a plan view.
In the structure described above, the first pressure compartment SA and the second pressure compartment SB are in communication with each other via the common liquid chamber SR, and the communication passage 772 of the nozzle N is connected to the first pressure compartment SA through the first passage EA and is connected to the second pressure compartment SB through the second passage EB. It is possible to change the pressure of the first pressure compartment SA by driving the first piezoelectric element 74A and change the pressure of the second pressure compartment SB by driving the second piezoelectric element 74B. Therefore, ink is supplied from the common liquid chamber SR to the first pressure compartment SA and the second pressure compartment SB, and, by driving the first piezoelectric element 74A and the second piezoelectric element 74B, it is possible to cause the ink to flow from the first pressure compartment SA and the second pressure compartment SB toward the communication passage 772. Because of this structure, the nozzle N is able to output ink flowing from both the first pressure compartment SA and the second pressure compartment SB, wherein the common liquid chamber SR functions as an ink supply passage. Therefore, compared with a structure in which the nozzle N is able to output ink flowing from one pressure compartment only, it is possible to increase the amount of ink ejected from the nozzle N.
The first pressure compartment SA is connected to the common liquid chamber SR through the first branch passage DA and is connected to the communication passage 772 through the first passage EA. The second pressure compartment SB is connected to the common liquid chamber SR through the second branch passage DB and is connected to the communication passage 772 through the second passage EB. Because of this structure, it is possible to produce a flow of ink that circulates in the order of, for example, the common liquid chamber SR→ the first branch passage DA→ the first pressure compartment SA→ the first passage EA→ the communication passage 772→ the second passage EB→ the second pressure compartment SB→ the common liquid chamber SR. In this way, the common liquid chamber SR functions as a part of an ink circulating passage, and it is possible to produce a flow of ink that circulates through a common passage between the first pressure compartment SA and the second pressure compartment SB and the communication passage 772 of the nozzle N. As explained above, in the present embodiment, a single common liquid chamber SR has a dual function, that is, a function of an ink supply passage and a function of an ink circulation passage. Therefore, compared with a structure in which separate common passages are provided for the first pressure compartment SA and the second pressure compartment SB, the circulating passage is shorter. The shorter circulation length reduces passage resistance. For this reason, circulation efficiency improves.
Moreover, in the present embodiment, a circulating flow of ink is produced for each of the plurality of ejectors 266 through the communication passage 772, which is near the meniscus of the nozzle N. Therefore, compared with a structure in which ink is circulated through a circulating common passage that is distant from the meniscus of the nozzle N, the effects of preventing ink from drying from the meniscus and preventing an increase in the viscosity of the ink, which results from drying, are very high. Moreover, in the present embodiment, it is possible to cause the common liquid chamber SR for supplying ink to function as a part of a circulating passage, meaning that it is unnecessary to provide a common passage for ink circulation separately from a common passage for ink supply. Therefore, a phenomenon that a part of ink of the first pressure compartment SA or the second pressure compartment SB is discharged into a common passage for ink circulation does not occur when an operation for ejecting ink from the nozzle N is performed. For this reason, compared with a structure in which a common passage for ink circulation is provided, it is possible to reduce a decrease in the amount of ink ejected from the nozzle N.
An example of a specific structure of the first piezoelectric element 74A and the second piezoelectric element 74B will now be explained. An example of a specific structure of the first piezoelectric element 74A and the second piezoelectric element 74B in arbitrary one of the plurality of ejectors 266 is illustrated in
As illustrated in
As illustrated in a plan view of
In lieu of the above structure, the first piezoelectric element 74A and the second piezoelectric element 74B may be separate elements that are independent of each other, wherein each of these two distinct elements has an individual first electrode 742 and an individual second electrode 746. However, in terms of higher degree of integration and simpler electric wiring, it is more advantageous to form a first drive element and a second drive element as the two active areas of one piezoelectric element than to separately arrange the first piezoelectric element 74A and the second piezoelectric element 74B as two distinct elements each having an individual first electrode 742 and an individual second electrode 746 independently.
The first electrode 742 of the present embodiment is formed as a common electrode on the surface of the diaphragm 73 continuously across all of the first piezoelectric elements 74A and the second piezoelectric elements 74B corresponding to the plurality of ejectors 266. The piezoelectric layer 744 is formed on the surface of the first electrode 742 (on the opposite surface that is not in contact with the diaphragm 73). Each of the second electrodes 746 is formed opposite to the diaphragm 73 with respect to the first electrode 742 in the layered structure. The piezoelectric layer 744 underlies each of the second electrodes 746 and is sandwiched between the first electrode 742 and each of the second electrodes 746. As described above, in the present embodiment, each of the second electrodes 746 is an individual electrode, and the second electrode 746 of the first piezoelectric element 74A and the second electrode 746 of the second piezoelectric element 74B are electrically independent of each other.
The second electrode 746 of the first piezoelectric element 74A is formed for each of the plurality of first pressure compartments SA. The second electrode 746 of the second piezoelectric element 74B is formed for each of the plurality of second pressure compartments SB. The first electrode 742 and the second electrodes 746 are electrically connected to the drive unit 262 via lead electrodes (not illustrated) respectively. According to this structure, the reference potential VM is supplied to the first electrode 742, which is a common electrode, and the drive signals V are supplied separately to the second electrode 746 of the first piezoelectric element 74A and the second electrode 746 of the second piezoelectric element 74B, which are individual electrodes. In the present embodiment, the first electrode 742 is a common electrode, and the second electrode 746 is an individual electrode. However, the structure is not limited to this example. The first electrode 742 may be an individual electrode, and the second electrode 746 may be a common electrode.
An example of an ejecting drive pulse W1a, which is applied to the first piezoelectric element 74A, is illustrated in the upper part of
In the present embodiment, the ejecting drive pulse W1b has the same waveform and the same phase as those of the ejecting drive pulse W1a. However, the waveform of the ejecting drive pulse W1b, for example, amplitude and/or frequency, may be different from that of the ejecting drive pulse W1a. Since the phase of the drive pulse applied to the first piezoelectric element 74A and the phase of the drive pulse applied to the second piezoelectric element 74B are identical to each other, it is possible to simultaneously drive the first piezoelectric element 74A and the second piezoelectric element 74B in the same direction when ink is ejected. This makes it easier to produce a flow of ink from the first pressure compartment SA toward the communication passage 772 through the first passage EA and a flow of ink from the second pressure compartment SB toward the communication passage 772 through the second passage EB when ink is ejected. Therefore, it is possible to increase the amount of ink ejected from the nozzle N.
Next, a specific example of the operation of the ejector 266 by the ejecting drive pulse W1a, W1b will now be explained. Each of the ejecting drive pulses W1a and W1b illustrated in
The first piezoelectric element 74A deforms to cause the vibration of the diaphragm 73 due to supply of the drive signal V by the ejecting drive pulse W1a. Therefore, the pressure of the first pressure compartment SA changes. The second piezoelectric element 74B deforms to cause the vibration of the diaphragm 73 due to supply of the drive signal V by the ejecting drive pulse W1b. Therefore, the pressure of the second pressure compartment SB changes. Because of this change in pressure, as indicated by arrows in
When the ejecting drive pulses W1a and W1b are applied, ink is ejected from the nozzle N; therefore, a flow toward the nozzle N is easier to be produced in each of the first passage EA and the second passage EB than a circulation flow back to the first pressure compartment SA or the second pressure compartment SB. Moreover, since the ejecting drive pulse W1b has the same phase as that of the ejecting drive pulse W1a, both a flow toward the nozzle N from the first passage EA and a flow toward the nozzle N from the second passage EB are produced easily in the communication passage 772. Therefore, compared with a structure that includes only one of the first passage EA and the second passage EB, it is possible to increase the amount of ink ejection.
The ejecting drive pulse W1a, W1b is not limited to the example illustrated in
An example of a circulating drive pulse W2a, which is applied to the first piezoelectric element 74A, is illustrated in the upper part of
A meniscus formed in the nozzle N is an interface between ink and air. Therefore, at the meniscus, the process of vaporization of a solvent such as moisture progresses due to drying, and a balance between a solute and a solvent contained in ink gets lost; therefore, an increase in ink viscosity, solute precipitation, etc. tends to progress. If an increase in ink viscosity, solute precipitation, etc. progresses, it becomes harder to eject ink from the nozzle N. This might cause poor ejection or, even worse, the clogging of the nozzle N. In the present embodiment, it is possible to circulate ink through the communication passage 772 near the nozzle N. Therefore, it is possible to effectively prevent ink from drying and increasing in viscosity at the meniscus of the nozzle N. Moreover, compared with ejecting viscous ink from the nozzle N by performing the aforementioned flushing operation, it is possible to reduce wasteful ink consumption.
In the present embodiment, the circulating drive pulse W2b has the same waveform as that of the circulating drive pulse W2a but is different in phase from the circulating drive pulse W2a. However, the circulating drive pulse W2b, for example, amplitude and/or frequency, may be different from that of the circulating drive pulse W2a. Since the phase of the drive pulse applied to the first piezoelectric element 74A and the phase of the drive pulse applied to the second piezoelectric element 74B are different from each other, it is possible to produce a phase difference between vibration transmitted to the first passage EA by driving the first piezoelectric element 74A and vibration transmitted to the second passage EB by driving the second piezoelectric element 74B. Therefore, it is possible to make the manner of transmission of vibration (i.e., how vibration is transmitted) to the first passage EA from the first pressure compartment SA and the manner of transmission of vibration to the second passage EB from the second pressure compartment SB different from each other. Moreover, when ink circulation is performed, ink in the first pressure compartment SA and ink in the second pressure compartment SB tend to flow toward, of the first passage EA and the second passage EB, one to which vibration transmission is easier.
Therefore, by making the manner of transmission of vibration to the first passage EA and the manner of transmission of vibration to the second passage EB different from each other, it becomes easier to produce a flow of ink that circulates in one specific direction through the communication passage 772, the first pressure compartment SA, and the second pressure compartment SB. Specifically, in ink circulation, when one of the first passage EA and the second passage EB becomes a going passage, such different manner of transmission of vibration makes it easier for the other to become a returning passage. Therefore, a flow of ink that circulates through the communication passage 772 of the nozzle N, and the first pressure compartment SA and the second pressure compartment SB via the common liquid chamber SR, is produced easily.
Next, a specific example of the operation of the ejector 266 by the circulating drive pulse W2a, W2b will now be explained. Each of the circulating drive pulses W2a and W2b illustrated in
If the waveform of one cycle time T is defined as one pulse wave,
Specifically, the application of the circulating drive pulse W2a to the first piezoelectric element 74A and the circulating drive pulse W2b to the second piezoelectric element 74B causes deformation and minute vibration of the first piezoelectric element 74A and the second piezoelectric element 74B separately from each other. Therefore, the area in the diaphragm 73 that overlaps with the first piezoelectric element 74A in a plan view vibrates as illustrated in the upper part of
Therefore, in the present embodiment, vibration is transmitted from the second pressure compartment SB to the second passage EB, which is located on the side where the second piezoelectric element 74B is provided, in the opposite phase in relation to the phase of transmission of vibration from the first pressure compartment SA to the first passage EA, which is located on the side where the first piezoelectric element 74A is provided. Therefore, as indicated by arrows in
The circulating drive pulse W2a, W2b is not limited to the example illustrated in
In the present embodiment, equality holds for the sectional area of the first passage EA and the sectional area of the second passage EB throughout the entirety from the pressure compartment side toward the communication passage 772. That is, as illustrated in
Since the sectional area of the first passage EA is equal to the sectional area of the second passage EB, the passage resistance of the first passage EA is also substantially equal to the passage resistance of the second passage EB. For this reason, when the flow indicated by arrows in
Incidentally, when the sectional area of the first passage EA is equal to the sectional area of the second passage EB, a reverse flow in the opposite direction (a clockwise flow circulating around the Y axis) against the direction indicated by arrows in
However, compared with a structure in which a flow of ink circulating in the opposite direction could be produced with substantially the same likelihood as that of a flow of ink circulating in the direction indicated by arrows in
In this respect, in the present embodiment, it is possible to make the manner of transmission of vibration to the first passage EA and the manner of transmission of vibration to the second passage EB different from each other because it is possible to drive the first piezoelectric element 74A over the first passage EA and the second piezoelectric element 74B over the second passage EB independently of each other. This makes it easier to produce a flow of ink that circulates in one specific direction through the communication passage 772, the first pressure compartment SA, and the second pressure compartment SB. Therefore, a flow of ink that circulates through the communication passage 772 of the nozzle N, the first pressure compartment SA, and the second pressure compartment SB is produced in a short time efficiently. Consequently, ink circulation efficiency is high.
For example, in
In
As explained above, even though the sectional area of the first passage EA is equal to the sectional area of the second passage EB, the present embodiment makes it easier to produce a flow of ink that circulates in one specific direction. Therefore, it is possible to produce a circulating flow of ink in a short time efficiently, thereby achieving high ink circulation efficiency. In the present embodiment, the phase difference dT between the circulating drive pulses W2a and W2b is equal to ½ pulse wave corresponding to one half of the cycle time T. However, the length of the phase difference dT is not limited to the illustrated example. For example, the phase difference dT may be equal to one pulse wave corresponding to one cycle time T, or may be equal to a plurality of pulse waves. Increasing the phase difference dT between the circulating drive pulses W2a and W2b makes it easier to produce a flow of ink that circulates in one direction.
The scope of the present disclosure is not limited to a structure in which the sectional area of the first passage EA is equal to the sectional area of the second passage EB. The first passage EA and the second passage EB may have portions whose sectional areas are different from each other. For example, in
In another example, the sectional area A2 of the pressure-compartment-side end of the second passage EB may be larger than the sectional area A1 of the pressure-compartment-side end of the first passage EA. According to this modified structure, when ink is circulated, it becomes easier for ink to flow out of the second pressure compartment SB into the second passage EB that has a larger sectional area, and it becomes easier for ink to flow into the first pressure compartment SA from the first passage EA that has a smaller sectional area. Therefore, the second passage EB becomes a going passage, and the first passage EA becomes a returning passage, and a flow of ink that circulates through the communication passage 772 of the nozzle N, the first pressure compartment SA, and the second pressure compartment SB in one direction is produced easily.
The first pressure compartment SA and the second pressure compartment SB of the present embodiment are arranged side by side in the X direction. In addition, the common liquid chamber SR is arranged between the first pressure compartment SA and the second pressure compartment SB in a plan view. Compared with a structure in which two common liquid chambers SR that are separately in communication with the first pressure compartment SA and the second pressure compartment SB respectively are arranged adjacently in the X direction in addition to the first pressure compartment SA and the second pressure compartment SB in a plan view, the structure of the present embodiment is smaller in the X direction. In the present embodiment, as illustrated in
Next, a second embodiment of the present disclosure will now be explained. In each exemplary embodiment described below, the same reference numerals as those used in the description of the first embodiment are assigned to elements that are the same in operation and/or function as those in the first embodiment, and a detailed explanation of them is omitted. The second embodiment discloses an example in which the layout of the first pressure compartment SA and the second pressure compartment SB is modified from that of the first embodiment.
As illustrated in
As illustrated in the sectional view of
As illustrated in
According to the structure of the second embodiment described above, the first pressure compartment SA and the second pressure compartment SB are arranged on the negative side in the X direction with respect to the common liquid chamber SR in a plan view. Therefore, it is possible to reduce the size in the X direction, compared with a structure in which the first pressure compartment SA is arranged on one side in the X direction with respect to the common liquid chamber SR, the second pressure compartment SB is arranged on the other side, and the common liquid chamber SR is arranged therebetween in a plan view.
In the structure of the second embodiment, similarly to the foregoing embodiment, for example, ejecting drive pulses having the same phase as illustrated in
Next, a third embodiment of the present disclosure will now be explained. The third embodiment discloses an example in which each one ejector 266 includes a plurality of the first pressure compartments SA and a plurality of the second pressure compartments SB. With this structure, it is possible to increase the amount of ink ejected from the nozzle N.
As illustrated in
As illustrated in the sectional view of
As illustrated in the sectional view of
As illustrated in
In the third embodiment described above, for ink ejection, ejecting drive pulses having the same phase are applied to the first piezoelectric element 74A and the second piezoelectric element 74B of the first structure portion P1″ and the first piezoelectric element 74A and the second piezoelectric element 74B of the second structure portion P2″. Therefore, it is possible to eject ink that flows from the first piezoelectric element 74A and the second piezoelectric element 74B of the first structure portion P1″ and ink that flows from the first piezoelectric element 74A and the second piezoelectric element 74B of the second structure portion P2″. For this reason, the amount of ink ejected from the nozzle N is approximately four times as large as the amount of ink that would be ejected if ink flowing from only one first pressure compartment SA or only one second pressure compartment SB were ejected.
For ink circulation, circulating drive pulses having phases different from each other are applied to the first piezoelectric element 74A and the second piezoelectric element 74B of the first structure portion P1″ and, in addition, circulating drive pulses having phases different from each other are applied to the first piezoelectric element 74A and the second piezoelectric element 74B of the second structure portion P2″. By this means, it is possible to produce a flow of ink that circulates through the communication passage 772 of the nozzle N, the first pressure compartment SA, and the second pressure compartment SB of the first structure portion P1″ and produce a flow of ink that circulates through the communication passage 772 of the nozzle N, the first pressure compartment SA, and the second pressure compartment SB of the second structure portion P2″.
Similarly to the foregoing embodiments, a single common liquid chamber SR has a dual function, that is, a function of an ink supply passage and a function of an ink circulation passage. Therefore, compared with a structure in which separate common passages are provided for the first pressure compartment SA and the second pressure compartment SB, the circulating passage is shorter. The shorter circulation length reduces passage resistance. For this reason, circulation efficiency improves. The number of the first structure portion P1″ and the second structure portion P2″ per the ejector 266 may be increased. Since such a modification increases the number of the first pressure compartments SA and the second pressure compartments SB, it is possible to further increase the amount of ink ejected from the nozzle N.
The exemplary modes and embodiments described above can be modified in various ways. Some specific examples of variation are described below. Any two or more selected from among the exemplary modes/embodiments described above and/or the variation examples described below may be combined as long as they are not contradictory to each other or one another.
(1) In the foregoing embodiments, a serial head that repeats reciprocating movement of the carriage 24, on which the liquid ejecting head 26 is mounted, in the X direction is taken as an example. However, the disclosed technique may be applied to a line head that includes the liquid ejecting head 26 provided linearly over the entire width of the medium 12.
(2) Although the piezoelectric-type liquid ejecting head 26 utilizing, as drive elements, piezoelectric elements that apply mechanical vibration to pressure compartments is disclosed as an example in the foregoing embodiments, a thermal liquid ejecting head utilizing, as drive elements, heat generation elements that produce air bubbles inside pressure compartments by heating may be used instead.
(3) The liquid ejecting apparatus 10 disclosed as examples in the foregoing embodiments can be applied to various kinds of equipment such as facsimiles and copiers, etc. in addition to print-only machines. The scope of application of the liquid ejecting apparatus 10 according to the present disclosure is not limited to printing. For example, a liquid ejecting apparatus that ejects a colorant solution can be used as a manufacturing apparatus for manufacturing a color filter for a liquid crystal display, an organic EL (electroluminescence) display, or an FED (surface emission display), etc. A liquid ejecting apparatus that ejects a solution of a conductive material can be used as a manufacturing apparatus for forming wiring lines and electrodes of a wiring substrate. Another non-limiting example of use is a biochip manufacturing apparatus that ejects a solution of bioorganic substances as a kind of liquid.
The present application is based on, and claims priority from JP Application Serial Number 2018-046862, filed Mar. 14, 2018, the disclosure of which is hereby incorporated by reference herein in its entirety.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2018-046862 | Mar 2018 | JP | national |
| Number | Name | Date | Kind |
|---|---|---|---|
| 20050123420 | Richter | Jun 2005 | A1 |
| 20050219280 | Hiwada | Oct 2005 | A1 |
| 20080079759 | Nagashima | Apr 2008 | A1 |
| 20110063350 | Kusunoki | Mar 2011 | A1 |
| 20110069118 | Ohzeki et al. | Mar 2011 | A1 |
| 20110134174 | Seto | Jun 2011 | A1 |
| 20140078224 | Park et al. | Mar 2014 | A1 |
| Number | Date | Country |
|---|---|---|
| 4806617 | Nov 2011 | JP |
| 5430316 | Feb 2014 | JP |
| 2014-061695 | Apr 2014 | JP |
| Number | Date | Country | |
|---|---|---|---|
| 20190283421 A1 | Sep 2019 | US |
