JP2023174012A - Liquid discharge head, and liquid discharge device having the same - Google Patents

Abstract

To accurately detect an average temperature of liquid in a whole flow channel.SOLUTION: A printer includes a head 1 that has a flow channel member 21 formed with a manifold flow channel 11 extending in a first direction D1 and communicated with a plurality of individual flow channels 19, a piezoelectric actuator 22 fixed to a top face 21a of the flow channel member 21, and two temperature sensors 81, 82. The piezoelectric actuator 22 includes a high potential electrode having a plurality of individual parts, a plurality of branch parts and stem parts, and a low potential electrode having a plurality of individual parts, a plurality of branch parts and stem parts. The stem parts of the high potential electrode are positioned opposite to the stem parts of the low potential electrode relative to at least a part of the manifold flow channel in the first direction D1. The temperature sensors 81, 82 are arranged in the first direction D1 between the stem parts of the high potential electrode and the stem parts of the low potential electrode.SELECTED DRAWING: Figure 2

Description

The present invention relates to a liquid ejection head that ejects liquid, and a liquid ejection apparatus having the same.

Patent Document 1 describes a flow path forming member (flow path member) in which a plurality of pressure chambers and a plurality of manifold flow paths (common flow paths) communicating with the plurality of pressure chambers are formed, and a flow path forming member on the surface of the flow path forming member. An inkjet head (liquid ejection head) is shown that includes a fixed piezoelectric actuator (actuator member). Each manifold flow path extends in one direction. The piezoelectric actuator has two conductive patterns (common electrodes). The two conductive patterns (common electrodes) each include a plurality of overlapping parts (individual parts) corresponding to the plurality of pressure chambers, and a plurality of connecting parts (branch parts) extending in one direction and connecting the plurality of overlapping parts. Another connecting portion (trunk) extending in a direction orthogonal to one direction and connecting a plurality of connecting portions. The end of the other connection portion of each conductive pattern is bent in one direction, and a contact point to which power is supplied from the power source is provided at the bent portion. Further, another connection portion of one conductive pattern is located opposite, in one direction, to a portion of the manifold flow path from another connection portion of the other conductive pattern.

JP2016-137641A

Another connection part of each conductive pattern is a part where electric charge is supplied via multiple connection parts to multiple overlapping parts by power supply, and compared to the connection parts and overlap parts, more charge flows and the amount of heat generated is large. It's easy. Therefore, both side portions of the flow path forming member sandwiching a part of the manifold flow path tend to become relatively high temperature, and the temperature of the ink in the manifold flow path does not become lower as it goes downstream, and is in a relatively stable state.

In order to maintain printing quality in such an ink temperature environment, it is conceivable to detect the average temperature of the liquid in the entire flow path using a temperature sensor, and to appropriately select the ejection waveform of the liquid based on the detection result. However, depending on the position of the temperature sensor, it may not be possible to accurately detect the average temperature of the liquid in the entire flow path, making it difficult to maintain recording quality.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a liquid ejection head that can accurately detect the average temperature of liquid in the entire flow path, and a liquid ejection apparatus having the same.

The liquid ejection head A of the present invention includes a nozzle and a pressure chamber communicating with the nozzle, and includes a plurality of individual channels arranged in a first direction, and a plurality of individual channels extending in the first direction. a flow path member in which a communicating common flow path is formed; and a second pressure chamber fixed to the surface of the flow path member and perpendicular to each of the pressure chambers of the plurality of individual flow paths, the surface, and the first direction. The apparatus includes an actuator member having a plurality of actuator parts overlapping in the direction, and a temperature sensor. The actuator member connects the plurality of first individual parts that constitute the plurality of actuator parts, the plurality of first branch parts that connect the plurality of first individual parts, and the plurality of first branch parts. A first common electrode having a first trunk provided with a contact point with a first power feeding part, a plurality of second individual parts constituting the plurality of actuator parts, and a plurality of second individual parts are connected. a second common electrode having a plurality of second branch parts that connect the plurality of second branch parts and a second trunk part that connects the plurality of second branch parts and is provided with a contact point with a second power feeding part; is located opposite the second trunk with respect to at least a portion of the common flow path in the first direction, and the temperature sensor is located between the first trunk and the second trunk in the first direction. is placed between.

In a first aspect, the liquid ejection apparatus of the present invention includes a transport mechanism that transports a recording medium in a transport direction, and the liquid ejection head A, and the temperature sensor is located on the surface of the flow path member. The actuator member is disposed upstream or downstream of the actuator member in the transport direction.

In a second aspect, the liquid ejection apparatus of the present invention includes a transport mechanism that transports a recording medium in a transport direction, and the liquid ejection head A, and the temperature sensor is located on the surface of the flow path member. The control unit is arranged upstream and downstream of the actuator member in the conveyance direction, respectively, and further includes a control unit that derives an average value of the detected temperatures detected by the two temperature sensors arranged upstream and downstream. ing.

In a third aspect, the liquid ejection apparatus of the present invention includes a transport mechanism that transports a recording medium in the transport direction, the liquid ejection head A, and a correction coefficient for correcting the detected temperature detected by the temperature sensor. It includes a storage section for storing information, and a control section for correcting the detected temperature based on the correction coefficient.

According to the liquid ejection head A of the present invention, the temperature sensor is disposed between the first and second trunks, which generate a relatively large amount of heat. Therefore, the average temperature of the liquid in the entire flow path can be detected with higher accuracy than when the temperature sensor is disposed outside the first and second trunks in the first direction.
According to the first aspect of the liquid ejecting device of the present invention, the temperature sensor is disposed between the first and second trunks, which generate a relatively large amount of heat. Therefore, the average temperature of the liquid in the entire flow path can be detected with higher accuracy than when the temperature sensor is disposed outside the first and second trunks in the first direction. Furthermore, it is possible to detect the average temperature of the liquid in the entire flow path based on the detected temperature detected by one temperature sensor disposed upstream or downstream in the transport direction. This simplifies the configuration. Furthermore, when the temperature sensor is disposed downstream of the actuator member, it is possible to detect the temperature at a location where the influence of cooling by the conveying airflow on the recording medium is small.
According to the second aspect of the liquid ejecting device of the present invention, the temperature sensor is disposed between the first and second trunks, which generate a relatively large amount of heat. Therefore, the average temperature of the liquid in the entire flow path can be detected with higher accuracy than when the temperature sensor is disposed outside the first and second trunks in the first direction. Furthermore, it is possible to reduce the influence of cooling caused by the conveying airflow on the recording medium, and it is possible to detect the average temperature of the liquid in the entire flow path with higher accuracy.
According to the third aspect of the liquid ejection device of the present invention, the temperature sensor is disposed between the first and second trunks, which generate relatively large amounts of heat. Therefore, the average temperature of the liquid in the entire flow path can be detected with higher accuracy than when the temperature sensor is disposed outside the first and second trunks in the first direction. Moreover, it becomes possible to correct the detected temperature detected by the temperature sensor. Therefore, it becomes possible to detect the average temperature of the liquid in the entire flow path with higher accuracy.

1 is an overall configuration diagram of a printer including a head according to an embodiment of the present invention. 2 is a plan view of the head shown in FIG. 1. FIG. 3 is an enlarged view of region III in FIG. 2. FIG. 4 is a sectional view taken along line IV-IV in FIG. 3. FIG. 3 is a plan view showing the top surface of the uppermost piezoelectric layer among the three piezoelectric layers constituting the piezoelectric actuator of FIG. 2. FIG. 3 is a plan view showing the upper surface of an intermediate piezoelectric layer among the three piezoelectric layers constituting the piezoelectric actuator of FIG. 2. FIG. 3 is a plan view showing the top surface of the lowermost piezoelectric layer among the three piezoelectric layers that constitute the piezoelectric actuator of FIG. 2. FIG. 4 is a sectional view taken along line VIII-VIII in FIG. 3. FIG. 9 is a diagram showing the operation of the actuator section in the cross section of FIG. 8. FIG.

The overall configuration of a printer 100 including a head 1 according to a preferred embodiment of the present invention will be described below.

Note that in the following description, the first direction D1 is the horizontal direction. The second direction D2 is a vertical direction and is orthogonal to the first direction D1. The third direction D3 is a horizontal direction, and is perpendicular to the first direction D1 and the second direction D2.

The printer 100 (the "liquid ejection apparatus" of the present invention) includes a head unit 1x including four heads 1, a platen 3, a transport mechanism 4, and a control section 5. The head unit 1x is elongated in the first direction D1, and ejects ink from the nozzle 15 (see FIGS. 3 and 4) onto the paper 9 (the "recording medium" of the present invention) in a fixed position. It is a line type. The four heads 1 ("liquid ejection heads" of the present invention) are each elongated in the first direction D1, and are arranged in a staggered manner in the first direction D1. The ink ejected from each head 1 is of the same color (for example, black ink).

The platen 3 is a flat plate member placed below the head unit 1x, and the paper 9 is placed on the upper surface of the platen 3.

The conveyance mechanism 4 includes two roller pairs 4a and 4b arranged with the platen 3 in between in the third direction D3. When the conveyance motor (not shown) is driven under the control of the control unit 5, the pair of rollers 4a and 4b rotate while sandwiching the paper 9, and the paper 9 is conveyed in the conveyance direction along the third direction D3. .

The control unit 5 includes a ROM (Read Only Memory), a RAM (Random Access Memory), and an ASIC (Application Specific Integrated Circuit). The ASIC executes recording processing and the like according to a program stored in the ROM. In the recording process, the control unit 5 controls the conveyance motor and driver IC (both not shown) based on recording commands (including image data) input from an external device such as a PC, thereby allowing the conveyance mechanism 4 to An image is recorded on the paper 9 by transporting the paper 9 and ejecting ink onto the paper 9 by the head 1.

Further, the control unit 5 has a storage unit 5a configured from a flash memory or the like. The storage unit 5a stores correction coefficients for correcting detected temperatures detected by temperature sensors 81 and 82, which will be described later. The control unit 5 corrects the detected temperature based on the correction coefficient.

Next, the configuration of the head 1 will be explained.

The head 1 includes a flow path member 21 and a piezoelectric actuator 22, as shown in FIG. Both the flow path member 21 and the piezoelectric actuator 22 have a rectangular shape in which the length in the first direction D1 is longer than the length in the third direction D3 in a plane orthogonal to the second direction D2.

As shown in FIG. 4, the flow path member 21 is composed of four plates 31 to 34 stacked in the second direction D2. Each of the plates 31 to 34 has holes formed therein that constitute flow paths. The flow path includes a plurality of individual flow paths 19 and a plurality of manifold flow paths 11 ("common flow path" in the present invention). Further, these plates 31 to 34 are made of a material with high thermal conductivity (metal, silicon, carbon, etc.).

A plurality of pressure chambers 10 are formed in the plate 31. Communication holes 12 and 13 are formed in the plate 32 for each pressure chamber 10. The communication holes 12 and 13 respectively overlap one end and the other end of the corresponding pressure chamber 10 in the third direction D3 in the second direction D2. A communication hole 14 is formed in the plate 33 for each communication hole 13 . The communication holes 14 overlap the corresponding communication holes 13 in the second direction D2. Twelve manifold channels 11 are further formed in the plate 33. The manifold channel 11 is provided for each pressure chamber row 10R (see FIG. 2), which is composed of a plurality of pressure chambers 10 arranged in the first direction D1. Each manifold flow path 11 extends in the first direction D1 and communicates with a plurality of pressure chambers 10 belonging to the corresponding pressure chamber row 10R via a communication hole 12. A plurality of nozzles 15 are formed on the plate 34. Each nozzle 15 overlaps the communication hole 14 in the second direction D2.

The individual flow path 19 is composed of a pressure chamber 10, communication holes 12 to 14 communicating with the pressure chamber 10, and a nozzle 15. That is, like the plurality of pressure chambers 10, the plurality of individual flow paths 19 are also arranged in the first direction D1.

Further, as shown in FIG. 2, in the channel member 21, two ink supply holes 8 are formed in an area on the upper surface 21a where the piezoelectric actuator 22 is not arranged (see FIG. 2). Each ink supply hole 8 communicates with an ink cartridge (not shown) via a tube. Further, each ink supply hole 8 is constituted by two holes penetrating the plates 31 and 32, and communicates with the six manifold channels 11. Ink supplied from the ink cartridge to each ink supply hole 8 via a tube is supplied to six manifold channels 11, respectively. Ink is supplied from each manifold channel 11 to the plurality of pressure chambers 10 belonging to each pressure chamber row 10R via communication holes 12. As described later, the piezoelectric actuator 22 is driven to apply pressure to the ink within the pressure chamber 10, and the ink is ejected from the nozzle 15 through the communication holes 13 and 14.

The piezoelectric actuator 22 (the "actuator member" of the present invention) is arranged on the upper surface 21a (the "surface" of the present invention) of the channel member 21, as shown in FIG. The piezoelectric actuator 22 includes three piezoelectric layers 41 to 43, a plurality of drive electrodes 51, a high potential electrode 52, and a low potential electrode 53.

The three piezoelectric layers 41 to 43 are each made of a piezoelectric material whose main component is lead zirconate titanate or the like, and are laminated in the second direction D2. The piezoelectric layer 42 is stacked on the piezoelectric layer 41 in the second direction D2. The piezoelectric layer 43 is laminated in the second direction D2 with respect to the piezoelectric layer 41 and the piezoelectric layer 42, and the piezoelectric layer 42 is sandwiched between the piezoelectric layer 43 and the piezoelectric layer 41. Note that the piezoelectric layer 41 corresponds to the "first piezoelectric layer" of the present invention, and the piezoelectric layer 42 corresponds to the "second piezoelectric layer" of the present invention. The piezoelectric layer 43 is arranged on the upper surface 21a of the plate 31 and covers all the pressure chambers 10 formed in the plate 31.

As shown in FIG. 3, the plurality of drive electrodes 51 ("first electrodes" of the present invention) are arranged on the upper surface of the piezoelectric layer 41, corresponding to each of the pressure chambers 10. Each drive electrode 51 has a main portion 51a and a protruding portion 51b. The main portion 51a overlaps substantially the entire area of the corresponding pressure chamber 10 in the second direction D2. The protruding portion 51b protrudes from the main portion 51a in the third direction D3, and does not overlap the corresponding pressure chamber 10 in the second direction D2. The protruding portion 51b is provided with a contact that is electrically connected to a COF (Chip On Film) (not shown). A driver IC (not shown) mounted on the COF individually applies a high potential (VDD potential) and a low potential (GND potential) to each drive electrode 51 via the wiring of the COF under the control of the control unit 5. Selectively give one of them.

As shown in FIG. 5, the plurality of drive electrodes 51 are arranged in the first direction D1, forming a plurality of drive electrode rows 51R corresponding to each of the pressure chamber rows 10R (see FIG. 2). The plurality of drive electrode rows 51R are lined up in the third direction D3.

For each drive electrode row 51R, dummy electrodes 59 are provided on one side (upper side in FIG. 7) and the other side (lower side in FIG. 7) in the first direction D1. The dummy electrodes 59 have the same planar size and shape as the drive electrodes 51, and are arranged at equal intervals in the first direction D1 together with the drive electrodes 51. The dummy electrode 59 is not electrically connected to the COF and no potential is applied to it.

In addition to the drive electrode 51 and the dummy electrode 59, two high potential connection electrode sections 54 and two low potential connection electrode sections 55 are provided on the upper surface of the piezoelectric layer 41.

The two high-potential connection electrode parts 54 (the "first power feeding part" of the present invention) are located at one end (the left end in FIG. 5) and the other end (the right end in FIG. 5) of the piezoelectric layer 41 in the third direction D3, respectively. It is arranged on one side (upper side in FIG. 5) of the piezoelectric layer 41 in the first direction D1. The two low-potential connection electrode parts 55 (the "second power supply part" of the present invention) are located at one end (the left end in FIG. 5) and the other end (the right end in FIG. 5) of the piezoelectric layer 41 in the third direction D3, respectively. It is arranged on the other side of the piezoelectric layer 41 in the first direction D1 (lower side in FIG. 5).

The high potential connection electrode section 54 and the low potential connection electrode section 55 each include a plurality of connection electrodes 54a and 55a arranged apart from each other in the first direction D1. The connection electrodes 54a and 55a have substantially the same size and shape in a plane. Under the control of the control unit 5, the driver IC applies a high potential (VDD potential) to the connection electrode 54a and a low potential (GND potential) to the connection electrode 55a via the COF wiring. The connection electrode 54a is held at a high potential, and the connection electrode 55a is held at a low potential.

As shown in FIG. 6, the high potential electrode 52 (the "first common electrode" of the present invention) is arranged on the upper surface of the piezoelectric layer 42, and includes a trunk 521 and a plurality of branches 523 branching from the trunk 521. , a plurality of individual parts 52a ("first individual part and another first individual part" of the present invention) branched from each branch part 523.

The trunk 521 (the "first trunk" of the present invention) has an extending portion 521a (the "first trunk" of the present invention) extending in the third direction D3 at one end (upper end in FIG. 6) of the piezoelectric layer 42 in the first direction D1. and two high potential receiving portions 521b (“contact and first contact portion” of the present invention) connected to both ends of the extension portion 521a in the third direction D3. The two high potential receptors 521b extend in the first direction D1 at one end (left end in FIG. 6) and the other end (right end in FIG. 6) of the piezoelectric layer 42 in the third direction D3, respectively.

The two high potential receiving parts 521b each overlap with several connection electrodes 54a that constitute the high potential connection electrode part 54 in the second direction D2. The two high potential receptors 521b are each electrically connected to the connection electrode 54a through a through hole formed in the piezoelectric layer 41, and receive a high potential from the connection electrode 54a.

The plurality of branch portions 523 (“first branch portions” of the present invention) are arranged in the third direction D3 and each extend from the extension portion 521a to the other side (lower side in FIG. 6) in the first direction D1. Each individual portion 52a has a portion that overlaps a central portion of each pressure chamber 10 in the first direction D1 in the second direction D2, and a portion that overlaps each drive electrode 51 in the second direction D2 (see FIG. 8).

The plurality of individual parts 52a are arranged in the first direction D1 as shown in FIG. 1 individual part sequence"). The plurality of individual part rows 52aR are lined up in the third direction D3.

As shown in FIG. 6, the extending portion 521a and the high potential receiving portion 521b of the trunk portion 521 are formed to have a wider planar size than the branch portions 523 and the individual portions 52a. Therefore, in the high potential electrode 52, the value of the product of charge and resistance is highest at the trunk 521. Therefore, when receiving a high potential from the connection electrode 54a, the trunk 521 generates more heat than the branch portions 523 and the individual portions 52a.

In addition to the high potential electrode 52, two low potential connection electrode sections 56, two floating electrode sections 64, and a floating electrode section 65 are provided on the upper surface of the piezoelectric layer 42.

The two low potential connection electrode parts 56 (the "second power supply part" of the present invention) are located at one end (the left end in FIG. 6) and the other end (the right end in FIG. 6) of the third direction D3 of the piezoelectric layer 42, respectively. It is arranged on the other side (lower side in FIG. 6) of the piezoelectric layer 42 in the first direction D1. The two low-potential connection electrode sections 56 each include two connection electrodes 56a and one connection electrode 56b that are spaced apart from each other in the first direction D1.

The two floating electrode parts 64 are connected to the high potential receiving part 521b and the low potential in the first direction D1 at one end (left end in FIG. 6) and the other end (right end in FIG. 6) of the third direction D3 of the piezoelectric layer 42, respectively. It is arranged between the connecting electrode section 56 and the connecting electrode section 56 . The two floating electrode sections 64 each include a plurality of floating electrodes 64a that are spaced apart from each other in the first direction D1.

The floating electrode portion 65 is arranged at the other end of the piezoelectric layer 42 in the first direction D1 (lower end in FIG. 6). The floating electrode section 65 includes a plurality of floating electrodes 65a arranged apart from each other in the third direction D3. The floating electrodes 65a have substantially the same size and shape in a plane, and are arranged at equal intervals in the third direction D3.

The connection electrode 56a of the low potential connection electrode section 56 and the floating electrode 64a of the floating electrode section 64 have substantially the same size and shape in a plane, and are arranged at equal intervals in the first direction D1. The connection electrode 56b has a longer length in the first direction D1 than the connection electrode 56a. The connection electrodes 56a and 56b are electrically connected to the connection electrode 55a through a through hole formed in the piezoelectric layer 41. On the other hand, each floating electrode 64a, 65a of the floating electrode parts 64, 65 is not electrically connected to any electrode, and no potential is applied thereto.

As shown in FIG. 7, the low potential electrode 53 (the "second common electrode" of the present invention) is arranged on the upper surface of the piezoelectric layer 43, and includes a trunk 531 and a plurality of branches 533 branching from the trunk 531. , a plurality of individual parts 53a ("second individual part and another second individual part" of the present invention) branched from each branch part 533.

The trunk 531 (the "second trunk" of the present invention) has an extending portion 531a (the "second trunk" of the present invention) extending in the third direction D3 at the other end of the piezoelectric layer 43 in the first direction D1 (lower end in FIG. 7). and two low potential receiving portions 531b (“contact point and second contact portion” of the present invention) connected to both ends of the extending portion 531a in the third direction D3. In addition, the trunk 531 is located opposite to the trunk 521 with respect to a part of the manifold flow path 11 in the first direction D1 (see FIGS. 2, 6, and 7). The two low potential receptors 531b extend in the first direction D1 at one end (left end in FIG. 7) and the other end (right end in FIG. 7) of the piezoelectric layer 43 in the third direction D3, respectively.

The two low potential receptors 531b each include several connection electrodes 55a (see FIG. 5) that constitute the low potential connection electrode section 55 and several connection electrodes 56a, 56b (see FIG. 5) that constitute the low potential connection electrode section 56. (see FIG. 6) in the second direction D2. The two low potential receptors 531b are electrically connected to the connection electrodes 56a and 56b through through holes formed in the piezoelectric layer 42, respectively. Therefore, each low potential receiving section 531b is electrically connected to the low potential connecting electrode section 55 (see FIG. 5) via the low potential connecting electrode section 56 (see FIG. 6), and the low potential connecting electrode section 55 receives a low potential from

The plurality of branch portions 533 (“second branch portions” of the present invention) are arranged in the third direction D3 and each extend from the extension portion 531a to one side (upper side in FIG. 7) in the first direction D1. Among the plurality of individual parts 53a, each individual part 53a, except for the individual parts 53a located at one end and the other end in the first direction D1, straddles two pressure chambers 10 that are adjacent to each other in the first direction D1. The pressure chamber 10 has a portion that overlaps with the two pressure chambers 10 in the second direction D2 (see FIG. 8). The individual portions 53a located at one end and the other end in the first direction D1 have portions that overlap with one pressure chamber 10 in the first direction D1. Further, each individual portion 53a has a portion that overlaps each drive electrode 51 in the second direction D2.

The plurality of individual parts 53a are arranged in the first direction D1 as shown in FIG. 2 separate parts). The plurality of individual part rows 53aR are lined up in the third direction D3.

As shown in FIG. 7, the extending portion 531a and the low potential receiving portion 531b of the trunk portion 531 are formed to have a wider planar size than the branch portion 533 and the individual portion 53a. Therefore, in the low potential electrode 53, the value of the product of charge and resistance is highest at the trunk 531. Therefore, when receiving a low potential from the low potential connection electrode portion 55, the trunk 531 generates more heat than the branch portions 533 and the individual portions 53a.

In addition to the low potential electrode 53, a high potential connection electrode section 57 and two floating electrode sections 66 are provided on the upper surface of the piezoelectric layer 43.

The high potential connection electrode section 57 includes a portion 57a extending in the third direction D3 at one end of the piezoelectric layer 43 in the first direction D1 (upper end in FIG. 7), and two electrodes connected to both ends of the portion 57a in the third direction D3. It has two portions 57b. The two portions 57b extend in the first direction D1 at one end (left end in FIG. 7) and the other end (right end in FIG. 7) of the piezoelectric layer 43 in the third direction D3, respectively.

The two portions 57b overlap each high potential receiving portion 521b (see FIG. 6) of the high potential electrode 52 in the second direction D2. The two portions 57b are electrically connected to each high potential receiving portion 521b via a through hole formed in the piezoelectric layer 42, respectively. Therefore, each portion 57b is electrically connected to the high potential connecting electrode section 54 (see FIG. 5) via the high potential receiving section 521b (see FIG. 6), and receives a high potential from the high potential connecting electrode section 54. receive. Note that the high potential connection electrode section 57 does not need to be connected to the high potential receiving section 521b. In this case, no potential is applied to the high potential connection electrode section 57.

The two floating electrode portions 66 have a portion 57b and a low potential receiving portion 531b in the first direction D1 at one end (left end in FIG. 7) and the other end (right end in FIG. 7) of the piezoelectric layer 43 in the third direction D3, respectively. is located between. The two floating electrode sections 66 each include a plurality of floating electrodes 66a that are spaced apart from each other in the first direction D1. The floating electrodes 66a have substantially the same size and shape in a plane, and are arranged at equal intervals in the first direction D1. Each floating electrode 66a is not electrically connected to any electrode and no potential is applied to it.

As shown in FIG. 8, a portion of the piezoelectric layer 41 sandwiched between the drive electrode 51 and the individual portion 52a of the high potential electrode 52 in the second direction D2 is referred to as a first active portion 91. A portion of the piezoelectric layers 42 and 43 that is sandwiched between the drive electrode 51 and the individual portion 53a of the low potential electrode 53 in the second direction D2 is referred to as a second active portion 92. The first active part 91 is mainly polarized upward, and the second active part 92 is mainly polarized downward. The piezoelectric actuator 22 has an actuator section 90 for each pressure chamber 10, including one first active section 91 and two second active sections 92 that sandwich the first active section 91 in the first direction D1. .

Here, with reference to FIG. 9, the operation of the actuator section 90 corresponding to a certain nozzle 15 when ink is ejected from the nozzle 15 will be described.

Before the printer 100 starts the recording operation, a low potential (GND potential) is applied to each drive electrode 51, as shown in FIG. 9(a). At this time, due to the potential difference between the drive electrode 51 and the high potential electrode 52, an upward electric field equal to the polarization direction is generated in the first active part 91, causing the first active part 91 to contract in the plane direction. As a result, the portions of the piezoelectric layers 41 to 43 that overlap the pressure chamber 10 in the second direction D2 are bent so as to be convex toward the pressure chamber 10 (downward). At this time, the pressure chamber 10 has a smaller volume than when the piezoelectric layers 41 to 43 are flat.

When the printer 100 starts a recording operation and ejects ink from a certain nozzle 15, first, as shown in FIG. ) to a high potential (VDD potential). At this time, the potential difference between the drive electrode 51 and the high potential electrode 52 is eliminated, so that the contraction of the first active portion 91 is eliminated. On the other hand, due to the potential difference between the drive electrode 51 and the low potential electrode 53, a downward electric field equal to the polarization direction is generated in the second active part 92, causing the second active part 92 to contract in the planar direction. However, the second active section 92 has a function of suppressing crosstalk (a phenomenon in which pressure fluctuations accompanying deformation of the actuator section 90 in a certain pressure chamber 10 are transmitted to another pressure chamber 10 adjacent to the pressure chamber 10). Therefore, it hardly contributes to the deformation of the actuator section 90. That is, at this time, the piezoelectric layers 41 to 43 do not bend so that the portions overlapping with the pressure chamber 10 in the second direction D2 are convex in a direction away from the pressure chamber 10 (upward), but are in a flat state. As a result, the volume of the pressure chamber 10 becomes larger than that in FIG. 9(a).

Thereafter, as shown in FIG. 9A, the potential of the drive electrode 51 corresponding to the nozzle 15 is switched from a high potential (VDD potential) to a low potential (GND potential). At this time, the potential difference between the drive electrode 51 and the low potential electrode 53 disappears, so that the contraction of the second active part 92 is eliminated. On the other hand, due to the potential difference between the drive electrode 51 and the high potential electrode 52, an upward electric field equal to the polarization direction is generated in the first active part 91, and the first active part 91 contracts in the planar direction. As a result, the portions of the piezoelectric layers 41 to 43 that overlap with the pressure chamber 10 in the first direction D1 are bent so as to be convex (downward) toward the pressure chamber 10. At this time, since the volume of the pressure chamber 10 is greatly reduced, a large pressure is applied to the ink within the pressure chamber 10, and the ink is ejected from the nozzle 15.

Here, the drive electrode 51, dummy electrode 59, high potential connection electrode section 54, and low potential connection electrode section 55 arranged on the upper surface of the piezoelectric layer 41 constitute the first electrode layer 71 (see FIG. 5). The high potential electrode 52, the low potential connection electrode section 56, and the floating electrode sections 64 and 65 arranged on the upper surface of the piezoelectric layer 42 constitute the second electrode layer 72 (see FIG. 6). The low potential electrode 53, the high potential connection electrode section 57, and the floating electrode section 66 arranged on the upper surface of the piezoelectric layer 43 constitute the third electrode layer 73 (see FIG. 7). Further, a high potential corresponds to the "first potential" of the present invention, and a low potential corresponds to the "second potential" of the present invention.

Furthermore, each head 1 has two temperature sensors 81 and 82, as shown in FIG. Two temperature sensors 81 and 82 are arranged on the upper surface 21a of the flow path member 21. The temperature sensor 81 is disposed at the upstream end of the channel member 21 and upstream of the piezoelectric actuator 22 in the conveyance direction. Further, the temperature sensor 82 is disposed at the downstream end of the flow path member and downstream of the piezoelectric actuator 22 in the conveyance direction.

Further, as shown in FIGS. 6 and 7, the two temperature sensors 81 and 82 are arranged between the trunk 521 of the high potential electrode 52 and the trunk 531 of the low potential electrode 53 in the first direction D1. . More specifically, the two temperature sensors 81 and 82 are arranged at the center between the extending portion 521a of the trunk 521 and the extending portion 531a of the trunk 531 in the first direction D1.

The temperature sensors 81 and 82 in this embodiment are, for example, NTC thermistors (Negative Temperature Coefficient Thermistors) made of a material (composite metal oxide such as Mn, Ni, Co, etc.) whose electrical resistance changes depending on the temperature. There are no particular limitations on the sensor as long as it is a detectable sensor. The detected temperatures detected by these temperature sensors 81 and 82 are output to the control section 5.

The control unit 5 corrects the detected temperatures detected by the temperature sensors 81 and 82 based on the correction coefficient. By conveying the paper 9 at a predetermined conveyance speed by the conveyance mechanism 4, an airflow along the conveyance direction is generated within the printer 100. Due to the air flow at this time, the bottom surface of the flow path member 21 is cooled on the upstream side in the conveyance direction than on the downstream side. In other words, the temperature on the upstream side of the bottom surface of the flow path member 21 in the conveying direction is lower than the temperature on the downstream side. Therefore, the detected temperature of the temperature sensor 81 located on the upstream side in the transport direction tends to be lower than that of the temperature sensor 82 located on the downstream side. The correction coefficient in this embodiment reduces the difference in detected temperature between the two temperature sensors 81 and 82 caused by paper conveyance at a predetermined conveyance speed by multiplying the detected temperature detected by at least one of the temperature sensors 81 and 82. However, the temperature is determined in advance through experiments so that the temperature is close to the actual average temperature of the ink inside the flow path member 21. Further, the correction coefficient is used to correct errors in detected temperatures caused by variations in the installation positions of the temperature sensors 81 and 82. In other words, the correction coefficient is derived in advance through experiments so that the temperature detected by each temperature sensor 81, 82 is multiplied by the correction coefficient so that the temperature is close to the actual average temperature of the ink in the flow path member 21. be. The control unit 5 derives the average value of the detected temperatures of the temperature sensors 81 and 82 corrected based on the correction coefficient. In this way, the average value (temperature) for each head 1 derived by the control unit 5 is used for ejection control for each head 1 (determining the drive voltage, drive pulse width, number of pulses, etc. applied to the actuator unit 90). .

As described above, according to the head 1 of the printer 100 of this embodiment, the temperature sensors 81 and 82 are arranged between the two trunks 521 and 531 that generate relatively large amounts of heat in the first direction D1. If the temperature sensors 81 and 82 are arranged outside the two trunks 521 and 531 in the first direction D1, the ink in the entire flow path of the flow path member 21 affected by the heat generated by the two trunks 521 and 531 It becomes difficult to accurately detect the average temperature of However, in the head 1 in this embodiment, the temperature sensors 81 and 82 are arranged between the two trunks 521 and 531 in the first direction D1, so the temperature sensors 81 and 82 are arranged between the two trunks 521 and 531 in the first direction D1. It becomes possible to detect the average temperature of the ink in the entire flow path of the flow path member 21 with higher accuracy than when the main body 521, 531 is disposed outside.

Furthermore, the temperature sensors 81 and 82 are arranged at the center between the trunk 521 and the trunk 531 in the first direction D1. This makes it possible to detect the average temperature of the ink in the entire flow path of the flow path member 21 with higher accuracy.

Furthermore, the temperature sensors 81 and 82 are arranged between the extending portion 521a and the extending portion 531a in the first direction D1. This makes it possible to arrange the temperature sensors 81 and 82 between the extending portions 521a and 531a, which are arranged in correspondence with the arrangement of the plurality of individual portions 52a and individual portions 53a. The extending portion 521a and the extending portion 531a are portions that generate relatively high heat. Therefore, it is possible to accurately detect the average temperature of the ink in the entire flow path of the flow path member 21.

The head 1 also includes a three-layer piezoelectric actuator 22 in which an actuator section 90 consisting of one first active section 91 and two second active sections 92 is formed for each pressure chamber 10 . In the piezoelectric actuator 22 having such a three-layer structure, pressure fluctuations caused by the deformation of the first active part 91 are canceled by the deformation of the second active part 92 when transmitted to the adjacent pressure chamber 10. , crosstalk can be effectively suppressed.

Further, the control unit 5 of the printer 100 derives the average value of the detected temperatures detected by the two temperature sensors 81 and 82 arranged upstream and downstream in the transport direction. This makes it possible to reduce the influence of cooling of the flow path member 21 due to the airflow conveying the paper 9, and it becomes possible to detect the average temperature of the ink in the entire flow path of the flow path member 21 with higher accuracy.

Further, the control unit 5 of the printer 100 corrects the detected temperatures detected by the temperature sensors 81 and 82 based on the correction coefficient. This makes it possible to correct the detected temperatures detected by the temperature sensors 81 and 82. Therefore, it becomes possible to detect the average temperature of the ink in the entire flow path of the flow path member 21 with higher accuracy.

In the embodiment described above, the head 1 of the printer 100 is provided with the temperature sensor 81 on the upstream side in the transport direction and the temperature sensor 82 on the downstream side in the transport direction, but only one of the temperature sensors is provided. You can leave it there. This makes it possible to detect the average temperature of the ink in the entire flow path of the flow path member 21 based on the detected temperature detected by one temperature sensor 81 (or 82) placed upstream or downstream in the conveyance direction. . Furthermore, when only the temperature sensor 82 disposed downstream of the piezoelectric actuator 22 is employed, it is possible to detect the temperature at a location where the influence of cooling by the conveying airflow on the paper 9 is small.

Further, a plurality of correction coefficients may be stored in the storage unit 5a. For example, a plurality of correction coefficients depending on the transport speed of the paper 9 may be stored. In this case, when the paper 9 is transported at the first transport speed, the detected temperature detected by the temperature sensors 81 and 82 is corrected based on the first correction coefficient, and the paper is transported at a second transport speed different from the first transport speed. 9 is transported, the detected temperatures detected by the temperature sensors 81 and 82 may be corrected based on a second correction coefficient different from the first correction coefficient.

The printer 100 in the above-described embodiment employs a line head (head unit 1x) in which the head 1 is fixed, but while the head 1 moves in a direction intersecting the conveyance direction, the paper P is moved from the nozzle 15 to the paper P. A serial type head may be used that forms an image by ejecting ink. In the case of such a serial printer, the head 1 is arranged so that the first direction D1 is parallel to the conveyance direction, and is moved by a carriage (not shown) in the third direction D3 to eject ink onto the paper 9 to form an image. do.

Even in such a serial printer, the temperature sensors 81 and 82 are arranged between the two trunks 521 and 531 in the first direction D1. Therefore, effects similar to those of the above-described embodiment can be obtained. In addition, in the structure similar to the above-mentioned, the same effect can be obtained.

Furthermore, in the serial printer according to this modification, the head 1 moves back and forth along the third direction D3. Therefore, the detected temperatures detected by the temperature sensors 81 and 82 are unlikely to have a temperature difference due to the influence of the conveying airflow of the paper P. However, by setting a correction coefficient for correcting the variation in detected temperature between the installation positions of the temperature sensors 81 and 82, and by having the control unit 5 multiply the detected temperature by the correction coefficient, the same effect as in the above-described embodiment can be achieved. Obtainable.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims. For example, the temperature sensors 81, 82 may be disposed between the two trunks 521, 531 in the first direction D1, and may be located closer to one of the extending portions than the center of the extending portions 521a and 531a. You can stop by. Further, although the temperature sensors 81 and 82 are installed on the upper surface 21a of the flow path member 21, if they are placed between the two trunks 521 and 531 in the first direction D1, they can be placed on other surfaces of the flow path member 21. It may be placed in

The control unit 5 does not need to correct the detected temperature based on the correction coefficient. In this case, the correction coefficient does not need to be stored in the storage unit 5a. Further, the control unit 5 may employ the temperature detected by one of the two temperature sensors 81 and 82 and use it for ejection control for each head 1.

The first potential is not limited to a high potential and the second potential is a low potential, but the first potential may be a low potential and the second potential may be a high potential.

The number of piezoelectric layers constituting the piezoelectric actuator 22 is three in the above embodiment, but may be two, four or more. For example, in the embodiment described above (see FIG. 4, etc.), a diaphragm made of stainless steel or the like may be provided instead of the piezoelectric layer 43. Alternatively, in the embodiment described above (see FIG. 4, etc.), another piezoelectric layer may be arranged between the piezoelectric layer 43 of the piezoelectric actuator 22 and the plate 31 of the flow path member 21.

The present invention is not limited to printers, but can also be applied to facsimiles, copy machines, multifunction devices, and the like. The present invention also relates to a liquid ejection head used for purposes other than image recording, and a liquid ejection device having the same (for example, a liquid ejection head that ejects a conductive liquid onto a substrate to form a conductive pattern, and a liquid ejection head using the same). It is also applicable to devices with The target of ejection is not limited to paper, and may be, for example, cloth, a substrate, or the like. The liquid ejected from the nozzle is not limited to ink, and may be any liquid (for example, a processing liquid that aggregates or precipitates components in the ink).

1 head (liquid ejection head)
4 Transport mechanism 5 Control unit 5a Storage unit 10 Pressure chamber 11 Manifold channel (common channel)
15 Nozzle 19 Individual channel 21 Channel member 21a Top surface (surface)
22 Piezoelectric actuator (actuator member)
81, 82 Temperature sensor 41 Piezoelectric layer (first piezoelectric layer)
42 Piezoelectric layer (second piezoelectric layer)
51 Drive electrode (first electrode)
52 High potential electrode (first common electrode)
52a Individual part (1st individual part)
52aR Individual part row (first individual part row)
53 Low potential electrode (second common electrode)
53a Individual Division (Second Individual Division)
53aR Individual part row (second individual part row)
54 High potential connection electrode part (first power supply part)
55, 56 Low potential connection electrode part (second power supply part)
71 First electrode layer 72 Second electrode layer 73 Third electrode layer 90 Actuator section 100 Printer (liquid ejection device)
521 Executive (1st executive)
521a Extension part (first extension part)
521b High potential receptor (contact, first contact)
523 Branch (first branch)
531 Executive (Second Executive)
531a Extension part (second extension part)
531b Low potential receptor (contact, second contact)
533 Branch (second branch)
D1 First direction D2 Second direction D3 Third direction

Claims (7)

A plurality of individual channels each including a nozzle and a pressure chamber communicating with the nozzle and arranged in a first direction, and a common channel extending in the first direction and communicating with the plurality of individual channels are formed. a flow path member;
an actuator member fixed to a surface of the flow path member and having a plurality of actuator parts overlapping each of the pressure chambers of the plurality of individual flow paths in a second direction perpendicular to the surface and the first direction;
Equipped with a temperature sensor,
The actuator member is
A plurality of first individual parts that constitute the plurality of actuator parts, a plurality of first branch parts that connect the plurality of first individual parts, and a first power feeding part that connects the plurality of first branch parts. a first common electrode having a first trunk provided with a contact;
a plurality of second individual parts that constitute the plurality of actuator parts; a plurality of second branch parts that connect the plurality of second individual parts; and a second power feeding part that connects the plurality of second branch parts; a second common electrode having a second trunk provided with a contact;
The first trunk is located opposite the second trunk with respect to at least a portion of the common flow path in the first direction,
The liquid ejection head is characterized in that the temperature sensor is disposed between the first trunk and the second trunk in the first direction. The liquid ejection head according to claim 1, wherein the temperature sensor is disposed in the center between the first trunk and the second trunk in the first direction. The first common electrode has a plurality of other first individual parts that constitute the plurality of actuator parts,
the plurality of first individual parts are arranged in the first direction;
the plurality of other first individual parts are arranged in the first direction,
The plurality of first individual parts and the plurality of other first individual parts form a plurality of first individual part rows arranged in a third direction perpendicular to the second direction and intersecting the first direction. ,
The second common electrode has a plurality of separate second individual parts that constitute the plurality of actuator parts,
the plurality of second individual parts are arranged in the first direction;
the plurality of other second individual parts are arranged in the first direction,
The plurality of second individual parts and the plurality of other second individual parts form a plurality of second individual part rows arranged in a third direction perpendicular to the second direction and intersecting the first direction. ,
The plurality of first branch parts and the plurality of second branch parts each extend in the first direction and are arranged in the third direction,
The first trunk has a first extension part extending in the third direction and connected to the plurality of first branch parts, and a first contact part provided with the contact point,
The second trunk has a second extension part extending in the third direction and connected to the plurality of second branch parts, and a second contact part provided with the contact point,
The liquid ejection head according to claim 1, wherein the temperature sensor is disposed between the first extending portion and the second extending portion in the first direction. The actuator member is
a first piezoelectric layer;
a second piezoelectric layer laminated in the second direction with respect to the first piezoelectric layer;
a first electrode layer disposed on a surface of the first piezoelectric layer opposite to the second piezoelectric layer in the second direction;
a second electrode layer disposed between the first piezoelectric layer and the second piezoelectric layer in the second direction;
a third electrode layer disposed on a surface of the second piezoelectric layer opposite to the first piezoelectric layer in the second direction;
The first electrode layer is a plurality of first electrodes to which either a first potential or a second potential different from the first potential is selectively applied, respectively, and the first electrode layer is a plurality of first electrodes to which either a first potential or a second potential different from the first potential is selectively applied, and the first electrode layer a plurality of first electrodes overlapping in the second direction with each of the
The second electrode layer includes the first common electrode held at the first potential,
The liquid ejection head according to claim 1, wherein the third electrode layer includes the second common electrode held at the second potential. a transport mechanism that transports the recording medium in the transport direction;
The liquid ejection head according to claim 1,
The liquid ejection device is characterized in that the temperature sensor is disposed on the surface of the flow path member, upstream or downstream of the actuator member in the transport direction. a transport mechanism that transports the recording medium in the transport direction;
The liquid ejection head according to claim 1,
The temperature sensor is disposed on the surface of the flow path member, upstream and downstream of the actuator member in the transport direction, respectively,
A liquid ejecting device further comprising a control unit that derives an average value of detected temperatures detected by the two temperature sensors arranged upstream and downstream. a transport mechanism that transports the recording medium in the transport direction;
The liquid ejection head according to any one of claims 1 to 6,
a storage unit that stores a correction coefficient for correcting the detected temperature detected by the temperature sensor;
A liquid ejection device comprising: a control section that corrects the detected temperature based on the correction coefficient.

Images