Liquid dispensing head and liquid dispensing device

Abstract

In a liquid discharge head equipped with a first energy generating element for discharging liquid into individual flow channels communicating with a discharge port and a second energy generating element for flowing the liquid, temperature unevenness is suppressed. [Solution] The device comprises a first channel through which one end of a first individual channel is connected, a second channel through which the other end of the first individual channel and one end of a second individual channel are connected, a third channel through which the other end of the second individual channel is connected, and a plurality of first openings, second openings and third openings provided in the first channel, second channel and third channel respectively for allowing liquid to flow in or out, where D1, D2 and D3 are the sizes of the non-opening portions in the first direction between two adjacent first openings, second openings and third openings, respectively, such that D2 > D1 and D2 > D3, and a temperature sensor provided in the non-opening portion between the second openings, and controls the driving of the second energy generating element based on the temperature detected by the temperature sensor.

Description

Technical Field

[0001] The present invention relates to a liquid ejection head and a liquid ejection device.

Background Art

[0002] In a liquid ejection head, a circulation type liquid ejection device that circulates ink is known for the purpose of discharging bubbles in a flow path and suppressing thickening of ink near a discharge port. As a method of circulating ink, there is a differential pressure method that uses a pressure difference. In the differential pressure method, by using a pressure adjustment mechanism or the like to make the pressure on the ink supply side (inlet side) for supplying ink to the discharge port higher than the pressure on the ink recovery side (outlet side), ink is caused to flow from the inlet side to the outlet side. At this time, in order to circulate the ink, it is necessary to return the ink that has flowed to the outlet side to the inlet side, and a pump is required as a mechanism for this purpose.In addition, there are some that circulate liquid between the liquid ejection head and the main body by providing a pump outside the head, such as in a recording device main body, and there are also some that circulate liquid within the liquid ejection head by providing a pump inside the liquid ejection head. However, in such a circulation method using the differential pressure method, mechanisms such as a pressure adjustment mechanism and a pump are required, and the recording device main body and the head tend to become larger.

[0003] Therefore, ink circulation methods other than the differential pressure method have been studied. Specifically, in an individual flow path communicating with a discharge port, in addition to a first energy generating element that generates energy for ejecting ink, a second energy generating element that generates energy for flowing liquid is arranged. And by driving the second energy generating element, a mechanism for circulating ink by flowing ink in the individual flow path is known. Patent Document 1 discloses a configuration in which a flow path extending in a direction intersecting a discharge port row in which a plurality of discharge ports are arranged is provided, and the flow path is provided with a first energy generating element and a second energy generating element.

Prior Art Documents

Patent Documents

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-104312 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] In a liquid discharge head equipped with a first energy generating element and a second energy generating element, the heat generated by driving the second energy generating element to make the liquid flow may cause temperature unevenness in the liquid discharge head.

[0006] The present invention aims to suppress temperature unevenness in a liquid discharge head that includes a first energy generating element for discharging liquid into individual flow channels communicating with a discharge port and a second energy generating element for causing the liquid to flow. [Means for solving the problem]

[0007] The present invention relates to a liquid dispensing head having a dispensing port for dispensing liquid, A first discharge port row consisting of a plurality of discharge ports arranged in a first direction, A second discharge port row comprising a plurality of discharge ports arranged in the first direction, wherein the second discharge port row is provided alongside the first discharge port row in a second direction intersecting the first direction, A plurality of first individual flow paths are connected to each of the plurality of discharge ports of the first discharge port row and extend in the second direction, Multiple second individual flow paths are connected to each of the multiple discharge ports of the second discharge port row and extend in the second direction, A first energy generating element is provided at a position corresponding to the discharge port in the plurality of first individual flow paths and the plurality of second individual flow paths, and generates energy for discharging liquid from the discharge port. A second energy generating element is provided in the plurality of first individual channels and the plurality of second individual channels in the second direction, alongside the first energy generating element, and generates energy for causing the liquid to flow. A first flow path is provided in the second direction, on the opposite side of the second discharge port row, with the first discharge port row in between, and through which one end of the plurality of first individual flow paths communicates; A second flow path is provided between the first and second discharge port rows in the second direction, and the other end of the plurality of first individual flow paths and one end of the plurality of second individual flow paths are in communication with each other. A third flow path is provided in the second direction, on the opposite side of the first discharge port row, with the second discharge port row in between, and the other ends of the plurality of second individual flow paths are connected to it. A plurality of first openings arranged in the first direction provided in the first flow path, the first openings for allowing liquid to flow into or out of the first flow path, A plurality of second openings arranged in the first direction provided in the second flow path, the second openings for allowing liquid to flow into or out of the second flow path, A plurality of third openings arranged in the first direction and provided in the third flow path, the third openings for allowing liquid to flow into or out of the third flow path, It has, The size of the first non-opening portion between the two adjacent first openings in the first direction is D1. The size of the second non-opening portion between the two adjacent second openings in the first direction is D2. The size of the third non-opening portion between the two adjacent third openings in the first direction is D3. So, D2 > D1, D2>D3 And, A temperature sensor provided in the second non-opening portion, A control means for controlling the drive of the second energy generating element based on the temperature detected by the temperature sensor, This is a liquid dispensing head characterized by having the following features. [Effects of the Invention]

[0008] According to the present invention, in a liquid discharge head equipped with a first energy generating element for discharging liquid into individual flow channels communicating with a discharge port and a second energy generating element for causing the liquid to flow, it is possible to suppress excessive temperature rise.

Brief Description of the Drawings

[0009] [Figure 1] It is a perspective view showing the configuration of the liquid ejection device of Example 1. [Figure 2] It is a view showing the liquid ejection head of Example 1. [Figure 3] It is a view for explaining the straight type ink circulation configuration of Example 1. [Figure 4] It is a view for explaining the straight type ink circulation configuration of Example 1. [Figure 5] It is a view for explaining the straight type ink circulation configuration of Example 1. [Figure 6] It is a view for explaining the U-shaped ink circulation configuration of the comparative example. [Figure 7] It is a view for explaining the U-shaped ink circulation configuration of the comparative example. [Figure 8] It is a view showing the control configuration of the liquid ejection device of Example 1. [Figure 9] It is a view showing the liquid ejection head of Example 1. [Figure 10] It is a view showing the liquid ejection head of Example 2. [Figure 11] It is a block diagram showing the control configuration of the liquid ejection device of Example 1.

Best Mode for Carrying Out the Invention

[0010] Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the matters of the present disclosure, and not all combinations of the features described in the present embodiments are essential for the solution means of the present disclosure. The same components are denoted by the same reference numerals. In the following description, first, the basic configuration of the present disclosure will be described, and then the characteristic parts of the present disclosure will be described.

[0011] (Example 1) [[ID=5O]] The liquid ejection device 50 of Embodiment 1 of the present invention will now be described. The liquid ejection device 50 is an inkjet recording device using an inkjet recording method and is equipped with a liquid ejection head 1 capable of ejecting ink as a liquid.

[0012] (Liquid discharge device) Figures 1(a) and 1(b) are perspective views showing the configuration of the liquid ejection device 50 of Example 1. The liquid ejection device 50 shown in Figures 1(a) and 1(b) is a serial-type liquid ejection device that performs image recording by ejecting liquid onto the recording medium P using a liquid ejection head 1 that scans in a direction intersecting the transport direction of the recording medium P. The present invention is not limited to serial-type liquid ejection devices, but is also applicable to page-wide type liquid ejection devices that perform image recording by ejecting liquid onto a recording medium being transported in the transport direction using a line head (page-wide type head) that is long in the page width direction of the recording medium. The liquid ejection head 1 of Example 1 is capable of ejecting four types of ink: black (K), cyan (C), magenta (M), and yellow (Y), and it is possible to record full-color images using these inks. The inks that can be ejected from the liquid ejection head 1 are not limited to the above four types of ink. The present invention is also applicable to liquid ejection heads that can eject other types of ink, and the type and number of inks ejected from the liquid ejection head are not limited.

[0013] In the liquid dispensing device 50, the liquid dispensing head 1 is mounted on a carriage 60. The carriage 60 reciprocates along the guide axis 51 in the main scanning direction (X direction). The recording medium P is transported by transport rollers 55, 56, 57, and 58, which are transport means, in the sub-scanning direction (Y direction) intersecting the main scanning direction. In Embodiment 1, the main scanning direction and the sub-scanning direction are orthogonal. In the figures referenced below, the Z direction represents the vertical direction and intersects the XY plane defined by the X and Y directions. In Embodiment 1, the Z direction is orthogonal to the XY plane.

[0014] Figure 1(a) shows a configuration in which a main ink tank 2 is provided outside the liquid ejection head 1 as a liquid storage unit. The ink stored in the main ink tank 2 is supplied to a sub-ink tank 54 on the liquid ejection head 1 side via an ink supply tube 59 etc., driven by the external pump 40. On the other hand, Figure 1(b) shows a configuration in which the liquid ejection head 1 does not have a main ink tank 2 outside the liquid ejection head 1, and the ink tank 54 is provided on the liquid ejection head 1. In this configuration, the liquid ejection head 1 is provided integrally with the ink tank 54 and can be made detachable from the carriage 60. Alternatively, the liquid ejection head 1 can be provided integrally with the carriage 60, and only the ink tank 54 can be made detachable. The external pump 40 that supplies ink to the ink tank 54 is a supply means that supplies ink to the liquid ejection head 1. Embodiment 1 will be explained using the configuration of Figure 1(a) as an example.

[0015] The liquid discharge head 1 is composed of individual discharge units, which will be described later. The specific configuration will be described later, but the individual discharge unit is a recording element unit having a discharge port for discharging liquid and an individual flow path communicating with the discharge port. A pressure chamber is formed at the position corresponding to the discharge port in the individual flow path, and a first energy generating element (discharge energy generating element) that generates energy for discharging liquid from the discharge port is provided in the pressure chamber. At a position different from the first energy generating element in the individual flow path, for the purpose of flowing the liquid A second energy generating element (fluid energy generating element) is provided that generates energy. The liquid discharge head 1 has a plurality of individual discharge units, and each individual discharge unit has a supply channel for supplying liquid to its individual flow path.

[0016] The liquid discharge may become unstable due to evaporation of volatile components such as water from the discharge port of the liquid discharge head 1, and the resulting concentration of solids near the discharge port. Various measures have been taken to prevent this. For example, the liquid discharge device 50 may be provided with a cap member (not shown) that can cover the discharge port surface of the liquid discharge head 1, located off-center in the X direction from the transport path of the recording medium P. The cap member is used to cover the discharge port surface of the liquid discharge head 1 when recording is not being performed, etc., in order to prevent drying of the discharge port and to protect it.

[0017] Furthermore, an ink suction mechanism (not shown) can also be provided. When an ink suction mechanism is provided, the cap member is used for operations such as suctioning ink from the discharge port. By performing this ink suction operation, the ink near the discharge port is refreshed, and the quality of the resulting image can be maintained.

[0018] Furthermore, when not recording, the printer can perform a pre-ejection (pre-ejection) to discard concentrated ink. It can also pre-eject ink (paper pre-ejection / in-page pre-ejection) in inconspicuous locations and amounts on the recording medium during recording. While these methods significantly improve image quality, they require discarding some ink to refresh the ejection port, thus necessitating a reduction in waste ink volume.

[0019] To address these challenges, by installing a second energy generating element (fluid energy generating element) in the individual flow path and circulating the ink within the flow path, it is possible to suppress the amount of waste ink while also suppressing drying at the discharge port and concentration of ink near the discharge port. More specifically, the number of pre-discharge and suction recovery cycles can be reduced. Furthermore, by reducing the number of pre-discharge cycles, throughput and yield can be improved.

[0020] The second energy generating element does not necessarily have to be provided in all individual dispensing units of the liquid dispensing head. If it is provided in some of the individual dispensing units, the above-mentioned effects can be obtained compared to when it is not provided.

[0021] Furthermore, the liquid ejection head 1 may be configured such that all sections corresponding to the four types of ink are equipped with a second energy generating element, or it may be configured such that only the section corresponding to one type of ink is equipped with a second energy generating element. The liquid ejection head 1 may also be configured to circulate only at least one type of ink, rather than circulating all four types of ink.

[0022] (Liquid dispensing head) The configuration of the liquid discharge head 1 in Example 1 will be described. Figures 2(a) to 2(d) show the configuration of the liquid discharge head 1 in Example 1. Figure 2(a) is an exploded perspective view of the liquid discharge head 1.

[0023] The liquid ejection head 1 includes four sub-ink tanks 54 for temporarily storing ink, and a liquid ejection tip 3 for ejecting the ink supplied from the sub-ink tanks 54 onto the recording medium P.

[0024] The liquid ejection head 1 further comprises a first support member 4, a second support member 7, and an electrical wiring member 5 (electrical wiring tape). A liquid ejection tip 3 is connected to one side of the first support member 4, and an ink tank 54 is connected to the other side. The first support member 4 is connected from one side to the other side. A channel is formed through which the first support member 4 supports the liquid ejection tip 3 and sends the ink supplied from the sub-ink tank 54 to the liquid ejection tip 3.

[0025] The second support member 7 is connected to the connection surface of the first support member 4 with the liquid discharge tip 3. The second support member 7 has an opening through which the liquid discharge tip 3 can be inserted, and is connected to the first support member 4 so that the liquid discharge tip 3 is positioned within the opening. The second support member 7 also supports the electrical wiring member 5.

[0026] The electrical wiring component 5 is electrically connected to the liquid ejection chip 3 and sends an ejection signal to the liquid ejection chip 3 for ejecting ink sent from the main body of the liquid ejection device 50.

[0027] In Example 1, the liquid ejection head 1 is fixedly supported on the carriage 60 of the liquid ejection device 50 by positioning means (not shown) and electrical contacts provided on the carriage 60. The liquid ejection head 1 ejects ink while moving together with the carriage 60 in the main scanning direction (X direction) and records onto the recording medium P.

[0028] An ink supply tube 59 is provided on an external pump 40 connected to the main ink tank 2, which is the source of the ink (see Figure 1(a)). A liquid connector (not shown) is provided at the tip of this ink supply tube 59. When the liquid discharge head 1 is mounted on the liquid discharge device 50, the liquid connector at the tip of the ink supply tube 59 is liquid-tightly connected to the liquid connector insertion port, which is the liquid inlet provided on the housing of the liquid discharge head 1. This forms an ink supply path from the ink tank 2 through the external pump 40 to the liquid discharge head 1. In Embodiment 1, since four types of ink are used, a total of four sets of ink tanks 2, external pumps 40, ink supply tubes 59, and sub-ink tanks 54 are provided, one for each ink. Four independent ink supply paths are formed, corresponding to each ink.

[0029] Thus, the liquid ejection device 50 is equipped with an ink supply system that supplies ink from an ink tank 2 located outside the liquid ejection head 1. However, the liquid ejection device 50 is not equipped with an ink recovery system for recovering the ink in the liquid ejection head 1 into the ink tank 2. Therefore, although the liquid ejection head 1 is provided with a liquid connector insertion port for connecting the ink supply tube 59 of the ink tank 2, it is not provided with a connector insertion port for connecting a tube to recover the ink from the liquid ejection head 1 into the ink tank 2. Note that a liquid connector insertion port is provided for each ink.

[0030] Figures 2(b), 2(c), and 2(d) show examples of the configuration of the liquid discharge tip 3 that constitute the liquid discharge head 1. Each liquid discharge tip 3 is provided with a discharge port 11 and a pad 15 used for electrical mounting. Figure 2(a) shows the chip configuration of Figure 2(b).

[0031] The liquid ejection head 1 is capable of ejecting four colors of ink. The four colors are, for example, black, cyan, magenta, and yellow. A row of ejection ports 28 is formed on the liquid ejection tip 3 for each ink color. One row of ejection ports 28 consists of a first row 25 and a second row 26, each consisting of multiple ejection ports 11 arranged at equal intervals in the Y direction (first direction), and the first row 25 and the second row 26 are arranged side by side in the X direction (second direction). The ejection ports 11 included in the first row 25 and the ejection ports 11 included in the second row 26 are offset from each other in the Y direction. Although the example shows a row of ejection ports 28 consisting of multiple ejection ports 11 arranged in two rows, a row of ejection ports 28 consisting of multiple ejection ports 11 arranged in a single row is also acceptable.

[0032] Figure 2(b) shows a configuration in which a single liquid ejection tip 3 is provided with four rows of ink ejection ports 28, allowing four colors of ink to be ejected from a single liquid ejection tip 3. Note that only the black ink has two rows. Alternatively, a configuration may be provided in which a total of five rows of discharge ports 28 are provided for four colors.

[0033] Figure 2(c) shows a configuration in which two liquid ejection tips 3 are provided with two ink ejection ports, allowing for the ejection of four colors of ink using two liquid ejection tips 3. For the configuration of mounting two liquid ejection tips 3, two liquid ejection tips 3 may be mounted on one liquid ejection head 1, or two liquid ejection heads 1, each mounted with one liquid ejection tip 3, may be prepared.

[0034] Figure 2(d) shows a configuration in which one liquid ejection tip 3 is provided with an ink ejection port for one color, and four liquid ejection tips 3 are capable of ejecting four colors of ink. For the configuration of mounting four liquid ejection tips 3, four liquid ejection tips 3 may be mounted on one liquid ejection head 1, or four liquid ejection heads 1, each equipped with one liquid ejection tip 3, may be prepared.

[0035] Furthermore, as shown in Figures 2(c) and 2(d), if the liquid dispensing tip 3 is divided into multiple parts, it is not necessary for all of them to have the same tip length. Also, various combinations of other colors are possible for the tip, and the same applies when the total number of colors exceeds four.

[0036] (Straight-type ink circulation configuration) Figures 3 to 5 illustrate the straight-type ink circulation configuration of Example 1. Figures 3 to 5 are simplified diagrams intended to explain the mechanism of circulation flow generation and its effects in a straight-type ink circulation configuration. Therefore, the configuration of the liquid ejection head 1 shown in Figures 3 to 5 differs in part from the configuration of the liquid ejection head 1 of Example 1 (described later using Figures 9 and 10). However, the mechanism of ink circulation generation and its effects, as explained with reference to Figures 3 to 5, are the same for the liquid ejection head 1 of Example 1. Furthermore, in the following explanation with reference to Figures 3 to 5, the parts applicable to the liquid ejection head 1 of Example 1 will be used as explanations for Example 1 unless otherwise specified.

[0037] Figure 3(a) is a diagram showing the configuration near the discharge port 11 of the liquid discharge head 1, and is a diagram showing the main components when the liquid discharge head 1 is viewed in the Z direction. Figure 3(b) is a cross-sectional view AA in Figure 3(a). Figure 3(c) is a cross-sectional view AA in Figure 3(a), and is a cross-sectional view of the liquid discharge head 1 with a different configuration from Figure 3(b). Figure 3(d) is a cross-sectional view AA in Figure 3(a), and is a diagram showing the flow of ink when ink is discharged from the discharge port.

[0038] The liquid dispensing head 1 has a stacked substrate 18 and an orifice plate 19, and the orifice plate 19 has a row of dispensing ports 63 consisting of a plurality of dispensing ports 11 arranged in a first direction (Y direction). An ink meniscus is spread over the dispensing ports 11, forming a dispensing port interface that serves as the interface between the ink and the atmosphere.

[0039] Between the substrate 18 and the orifice plate 19, separated by a partition wall 21, are multiple individual flow channels 23 that communicate with each of the multiple discharge ports 11 and extend in a second direction (X direction). The individual flow channels 23 extend linearly in a second direction (X direction) that intersects with the first direction (Y direction) in the discharge port row 63 where the multiple discharge ports 11 are lined up. In the example in Figure 3, the second direction is perpendicular to the first direction.

[0040] Furthermore, a first channel 61 is formed through which one end of multiple individual channels 23 is connected, and a second channel 62 is formed through which the other ends of multiple individual channels 23 are connected. The first channel 61 and the second channel 62 each extend in the Y direction and are located on opposite sides of the discharge port row 63 in the X direction.

[0041] In the individual flow path 23, a pressure chamber 12 is formed at a position corresponding to the discharge port 11. The pressure chamber 12 communicates with the first flow path 61 via the connecting flow path 13, and with the second flow path 61 via the connecting flow path 10. It communicates with the flow path 62. That is, the individual flow path 23 includes the pressure chamber 12, the connecting flow path 10, and the connecting flow path 13.

[0042] The substrate 18 is provided with a first energy generating element 14 (discharge energy generating element) at a position corresponding to the discharge port 11, which generates energy to discharge the ink from the pressure chamber 12. Here, an electrothermal conversion element is used as the first energy generating element 14. By driving the first energy generating element 14 to generate heat, the ink in the pressure chamber 12 is foamed, and the resulting foaming energy can be used to discharge the ink from the discharge port 11. Note that the first energy generating element 14 is not limited to an electrothermal conversion element, and a piezoelectric element or the like can be used.

[0043] Furthermore, the substrate 18 is provided with a second energy generating element 24 (fluid energy generating element) that generates energy to create a circulating flow 27 (fluid flow) in the ink within the individual flow channels 23, as indicated by the arrows. Here, the second energy generating element 24 is an electrothermal conversion element. The second energy generating element 24 is provided at a different position from the first energy generating element 14 in the X direction.

[0044] The first channel 61 has multiple first openings 22 arranged in the Y direction to allow ink to flow in or out with the common channel 29. The second channel 62 has multiple second openings 32 arranged in the Y direction to allow ink to flow in or out with the common channel 29. The first openings 22 and the second openings 32 each penetrate the substrate 18 in the stacking direction.

[0045] The first energy generating element 14, the discharge port 11, and the pressure chamber 12 are located closer to the second opening 32 than to the first opening 22. The second energy generating element 24 is located closer to the first opening 22 than to the second opening 32. The individual flow path 23 communicates with the first opening 22 at one end in the X direction (-X direction side) and with the second opening 32 at the other end (+X direction side). The connecting flow path 13 is located closer to the second energy generating element 24 in the X direction than to the discharge port row 63. The X-direction ends of the individual flow path 23 are located on opposite sides of the discharge port row 63.

[0046] There are mainly two types of ink flow in the individual flow channels 23: (1) a first ink flow for refilling after ink ejection by driving the first energy generating element 14, and (2) a second ink flow which is a circulating flow 27 generated by driving the second energy generating element 24.

[0047] When the first energy generating element 14 is driven and ink is ejected from the discharge port 11, a flow 37 is generated in which ink flows into the pressure chamber 12 of the individual flow path 23 from both the first opening 22 and the second opening 32, as shown in Figure 3(d). As a result, ink is supplied to the individual flow path 23 from the first opening 22 and the second opening 32.

[0048] When the second energy generating element 24 is driven to form a circulating flow 27, ink flows into the individual channel 23 from the inlet 37 on the connecting channel 13 side (first opening 22 side) and flows out from the outlet 38 on the connecting channel 10 side (second opening 32 side). The ink that flows out from the second opening 32 returns to the first opening 22 via the common channel 29. As a result, a circulating flow 27, indicated by the arrow, is generated within the individual channel 23.

[0049] In the configuration shown in Figure 3(b), the first opening 22 and the second opening 32 are connected to a common channel 29 within the tip of the liquid discharge head 1. In the configuration shown in Figure 3(c), the first opening 22 and the second opening 32 are connected to independent channels 291 and 292 within the tip of the liquid discharge head 1, and are connected to a common channel outside the tip of the liquid discharge head 1. The present invention is applicable to either configuration.

[0050] Filters can be provided in the ink circulation channels inside and outside the liquid ejection head 1 to remove foreign matter from the ink. In the example shown in Figure 3, the filters 31 are provided near the end of one end (the second energy generating element 24 side) and the other end (the first energy generating element 14 side) of the individual channel 23 in the X direction. Alternatively, a filter may be placed between the first energy generating element 14 and the second energy generating element 24 in the individual channel 23. In this case, a filter does not need to be placed near the end of one end (the second energy generating element 24 side) of the individual channel 23 in the X direction.

[0051] In the liquid discharge head 1, a first energy generating element 14 and a second energy generating element 24 are arranged side by side in the X direction within an individual channel 23 that extends linearly in the X direction. By driving the second energy generating element 24, a circulating flow 27 of ink can be generated within the individual channel 23. Both ends of the individual channel 23 are located on opposite sides of each other in the X direction with respect to the discharge port row 63. Therefore, the inlet 37 (upstream end) and outlet 38 (downstream end) of the circulating flow 27 are connected to different first channel 61 and second channel 62, respectively, and are separated from each other. This type of ink circulation configuration is called a straight type.

[0052] (The process of generating circulating flow) Figure 4 is a diagram illustrating the process of generating ink circulation flow by driving the second energy generating element 24. Figures 4(a), 4(b), and 4(c) are cross-sectional views similar to those in Figure 3(b), showing the process in which the ink is heated by the second energy generating element 24, and bubbles are generated, grown, contracted, and de-foamed due to boiling of the ink film.

[0053] Figure 4(a) shows how bubbles B are generated by driving the second energy generating element 24 (circulation heater). The second energy generating element 24 is located closer to the first opening 22 than to the second opening 32. Therefore, the flow resistance R1 between the second energy generating element 24 and the first opening 22 is smaller than the flow resistance R2 between the second energy generating element 24 and the second opening 32. Figure 4(a) shows an equivalent circuit where these flow resistances R1 and R2 are represented as electrical resistances. Bubbles B generated by the boiling of the ink film grow biased towards the first flow channel 61 side, where the flow resistance R1 is smaller, due to the difference in flow resistances R1 and R2, as shown in Figure 4(a). Therefore, within the individual flow channels 23, the ink flow Fa toward the first flow channel 61 is larger than the ink flow Fb toward the second flow channel 62.

[0054] Figure 4(b) shows the flow of ink during the contraction process of bubble B. During the contraction process of bubble B, ink flows in to compensate for the volume lost due to the contraction. At that time, as shown in Figure 4(b), the flow of ink Fc flowing in from the first opening 22 on the side with the small flow resistance R1 is greater than the flow of ink Fd flowing in from the second opening 32 on the side with the large flow resistance R2. Also, the defoaming position of bubble B is shifted from above the second energy generating element 24 towards the second opening 32.

[0055] Figure 4(c) shows the flow of ink after the bubbles B have been defoamed. From the relationship Fc > Fd that occurred in Figure 4(b), a circulating flow F of ink is generated from the first opening 22 to the second opening 32.

[0056] The magnitude of this circulating flow F is influenced by the ratio of flow resistances R1 and R2 and the size of the bubbles B. For example, when an electric heat conversion element (heater) is used as the second energy generating element 24, it is preferable that the second energy generating element 24 is located closer to one end of the individual flow path 23 than the first energy generating element 14. More specifically, it is preferable to set the flow resistance ratio R1 / R2 to a range of 0.05 to 0.40. By setting the flow resistance ratio R1 / R2 to this range, the circulating flow F can be made to a maximum value.

[0057] As shown in Figures 4(a) and 4(b), the circulating flow F can be increased by increasing the ink flow Fa toward the first channel 61 and the ink flow Fc flowing in from the first opening 22. Therefore, reducing the flow resistance R1 is effective. Similarly, the circulating flow F can be increased by reducing the ink flow Fb toward the second channel 62 and the ink flow Fd flowing in from the second opening 32. Therefore, increasing the flow resistance R2 is effective. In conclusion, the circulating flow F can be increased by reducing the flow resistance R1 and increasing the flow resistance R2, that is, by reducing the flow resistance ratio R1 / R2.

[0058] Furthermore, as the accumulation of bubbles B increases, the volume of ink removed from the individual channels 23 by foaming increases, thus increasing the circulating flow F. Possible methods to increase the volume of bubbles B include increasing the size of the second energy generating element 24, widening the width and height of the connecting channels 13 to reduce the flow resistance R1, reducing the ink viscosity, increasing the temperature of the liquid ejection head 1, and using double pulses for the drive pulse.

[0059] A portion of the circulating ink flow F enters the discharge port 11, sending the concentrated ink inside the discharge port 11 towards the second opening 32, and allowing fresh ink to flow into the discharge port 11 from the first opening 22 through the connecting channel 13. This suppresses the accumulation of concentrated ink inside the discharge port 11, reduces the effects of the concentrated ink, and maintains the initial ink discharge state.

[0060] The circulating flow F is a transient flow that occurs in conjunction with the growth and contraction process of the generated bubbles B. Therefore, after the bubbles B are defoamed, the inertial flow decays over time and stops after a certain period of time. By repeatedly driving the second energy generating element 24, the circulating flow F can be generated steadily for a certain period of time. The driving period of the second energy generating element 24 is not particularly limited, as long as it is sufficient to discharge the concentrated ink from the discharge port 11. However, since the time from the generation to the defoaming of bubbles B is about 10 μs, the effect will be reduced if driven at a high driving frequency such as 100 kHz. Therefore, it is preferable to drive the second energy generating element 24 with a period of, for example, 100 Hz to several tens of kHz.

[0061] Increasing the drive frequency maintains the circulating flow F, thereby increasing the efficiency of discharging concentrated ink. On the other hand, it is necessary to consider the temperature rise of the ink due to the heat generated by driving the second energy generating element 24. Therefore, it is preferable to appropriately control the number of times the second energy generating element 24 is driven.

[0062] (U-shaped ink circulation configuration) As a comparative example to the straight-type ink circulation configuration, a U-shaped ink circulation configuration will be described. Figure 7 shows the liquid discharge head of the comparative example. Figure 7(a) shows the configuration near the discharge port 11 of the liquid discharge head of the comparative example, and is a diagram showing the main components when the liquid discharge head 1 is viewed in the Z direction. Figure 7(b) is a cross-sectional view of AA in Figure 7(a). Figure 7(c) shows the vicinity of the individual flow paths in Figure 7(a).

[0063] The comparative example liquid discharge head has a stacked substrate 18 and an orifice plate 19, and the orifice plate 19 has a row of discharge ports 63 consisting of a plurality of discharge ports 11 arranged in a first direction (Y direction). Parallel to the row of discharge ports 63, a first energy generating element 14 and a second energy generating element 24 are arranged alternately.

[0064] Between the substrate 18 and the orifice plate 19, separated by a partition wall 21, are multiple individual channels 23 formed in a U-shape, each communicating with a plurality of discharge ports 11. Each individual channel 23 has a first portion 33 and a second portion 34 extending in the X direction, and a third portion 35 extending in the Y direction that connects one end of the first portion 33 and the second portion 34 in the X direction. The other end of section 33 and the second section 34 in the X direction communicates with the flow path 64, and the flow path 64 communicates with the common flow path 43. The ends of the individual flow paths 23 are adjacent in the Y direction and communicate with the flow path 64 on the same side (one side) in the X direction. The common flow path 43 is provided so as to penetrate the substrate 18.

[0065] The first section 33 is provided with a second energy generating element 24, and the second section 34 is provided with a pressure chamber 12 and a first energy generating element 14. The individual flow path 23 is a flow path formed by bending in a U shape to connect the first energy generating element 14 and the second energy generating element 24, which are arranged side by side in the Y direction.

[0066] In the individual flow path 23, a pressure chamber 12 is formed at a position corresponding to the discharge port 11. The pressure chamber 12 communicates with the flow path 64 via a connecting flow path 10 and with the flow path 64 via a connecting flow path 13. That is, the individual flow path 23 includes the pressure chamber 12, the connecting flow path 10, and the connecting flow path 13. The connecting flow path 13 is formed in part of the first section 33, the third section 35, and part of the second section 34, and the connecting flow path 10 is formed in part of the second section 34. The first energy generating element 14 is located near the connection between the connecting flow path 10 and the flow path 64, and the second energy generating element 24 is located near the connection between the connecting flow path 13 and the flow path 64.

[0067] The ink flow in the individual flow path 23 consists of (1) a first ink flow for refilling after ink ejection by driving the first energy generating element 14, and (2) a second ink flow which is a circulating flow 27 generated by driving the second energy generating element 24.

[0068] When the first energy generating element 14 is driven and ink is ejected from the ejection port 11, ink flows into the pressure chamber 12 from both the connecting channel 10 side and the connecting channel 13 side in order to supply ink from the common channel 43 accompanying the ejection.

[0069] When the second energy generating element 24 is driven to form a circulating flow 27, ink flows into the individual channel 23 from the inlet 39 on the connecting channel 13 side and flows out from the outlet 36 on the connecting channel 10 side. The circulating flow 27, indicated by the arrows, generated in the individual channel 23 causes ink to flow in and out of the common channel 43. Alternatively, a configuration like the one shown in Figure 3 may be used, in which the channel 64 communicates with a common channel (not shown) via multiple openings arranged in the Y direction. In this case, the multiple openings communicate with the common channel within the chip, similar to Figure 3(b).

[0070] In the comparative example liquid discharge head, a first energy generating element 14 and a second energy generating element 24 are arranged in the Y direction along the discharge port row 63 within a U-shaped individual channel 23. By driving the second energy generating element 24, a circulating flow 27 of ink can be generated within the individual channel 23. Both ends of the individual channel 23 are located on the same side (one side) in the X direction with respect to the discharge port row 63. Therefore, the inlet 39 (upstream end) and outlet 36 (downstream end) of the circulating flow 27 are connected to a common channel 64. This type of ink circulation configuration is called a U-shape.

[0071] (recirculation concentration) Figure 5 illustrates the ink circulation and concentration in a straight-type ink circulation configuration. In Figure 5, the degree of ink concentration is represented by shades of gray, with darker areas indicating a higher degree of concentration.

[0072] Figure 5(a) shows the state when the recording operation by the liquid ejection device 50 is temporarily suspended. When the recording operation is temporarily suspended, volatile components of the ink evaporate from the ejection port 11, and ink concentration progresses in the vicinity of the ejection port 11.

[0073] Figure 5(b) shows the subsequent flow after the second energy generating element 24 has generated a circulating flow 27. The following describes the subsequent state. The circulating flow 27 eliminates the concentration near the discharge port 11. The concentrated ink near the discharge port 11 is discharged from the outlet 38, and fresh ink flows in from the inlet 37, eliminating the concentration throughout the entire individual flow path 23.

[0074] Figure 5(c) shows the state after the recording operation is temporarily paused again. Similar to the state in Figure 5(a), ink concentration progresses near the ejection port 11. Figure 5(d) shows the state immediately after the second energy generating element 24 generates a circulating flow 27 again. Similar to the state in Figure 5(b), the concentration near the discharge port 11 is eliminated, and the concentration is eliminated throughout the entire individual flow path 23.

[0075] Thus, in a straight-type ink circulation configuration where the inlet 37 and outlet 38 of the individual flow path 23 are separated, the concentrated state is resolved even if the pause and circulation operation is repeated.

[0076] Figure 6 illustrates the ink circulation and concentration in the U-shaped ink circulation configuration of the comparative example.

[0077] Figure 6(a) shows the state when the recording operation by the liquid ejection device is temporarily suspended. When the recording operation is temporarily suspended, ink concentration progresses near the ejection port 11.

[0078] Figure 6(b) shows the state immediately after the second energy generating element 24 generates the circulating flow 27. In the U-shaped ink circulation configuration, the inlet 39 and outlet 36 of the individual flow channels 23 are connected to and close to the common flow channel 64. Therefore, although the ink concentrated near the discharge port 11 is discharged from the outlet 36 of the individual flow channel 23, it can flow back into the individual flow channel 23 from the inlet 39. As a result, even when the circulating flow 27 is generated, the entire individual flow channel 23 is replaced with slightly concentrated ink rather than fresh ink. This phenomenon is called recirculation concentration.

[0079] Figure 6(c) shows the state after the recording operation is temporarily paused again. From the state shown in Figure 6(b), further ink concentration progresses near the ejection port 11.

[0080] Figure 6(d) shows the state immediately after the second energy generating element 24 generates the circulating flow 27 again. As explained in Figure 6(b), due to the effect of recirculation concentration, the entire individual channel 23 is replaced with ink that is even more concentrated than in Figure 6(b).

[0081] Thus, in a U-shaped ink circulation configuration where the inlet 39 and outlet 36 of the individual flow path 23 are adjacent, if the circulation operation is repeated with temporary pauses, the concentrated state is not resolved, and concentration gradually progresses throughout the entire individual flow path 23. Furthermore, even without repeated circulation operations, if the vicinity of the discharge port 11 becomes highly concentrated due to long pause times, the concentrated state is difficult to improve even with the first circulation operation. This is because the degree of improvement in the concentrated state through recirculation concentration is small.

[0082] Therefore, in the straight type, where the inlet and outlet of individual flow paths are separate, and in the U-shaped type, where the inlet and outlet of individual flow paths are adjacent, there are differences in how the concentrated ink is resolved when circulation is performed after a temporary pause, due to the difference in the effect of the discharged concentrated ink. In the straight type, the concentrated state is easily resolved including the entire individual flow path, so a decrease in discharge stability due to concentrated ink is less likely to occur. On the other hand, in the U-shaped type, the concentrated state is difficult to resolve including the entire individual flow path due to recirculation concentration, so discharge tends to become unstable depending on the overall concentration of the individual flow path.

[0083] (ink) An electrothermal conversion element (circulation heater) is used as the second energy generation element 24 in the individual flow channels. By creating an ink circulation flow within 23, the effect of concentrated ink thickened by the evaporation of volatile components at the discharge port 11 can be suppressed. This allows for maintaining a good ink discharge state, reducing changes in discharge speed, and stabilizing the discharge.

[0084] Here, the type of colorant and solid content of the ink used may differ depending on the application of the liquid ejection head 1 and the liquid ejection device 50. For example, on plain paper, it is conceivable to use ink with reduced water content to suppress curling (warping) and cockling (wavy wrinkles) caused by water in the ink. In inks with low water content, the concentration of solids other than water, such as organic solvents, pigments, and resins, is high, so a rapid increase in viscosity is likely to occur as the water evaporates, which can easily lead to a decrease in ink ejection stability. Generally, inks with a solid content of 10 wt% (mass%) or more can be said to have a high solid content.

[0085] In the liquid discharge head 1 of Example 1, a circulating flow 27 can be generated in the individual flow path 23 having a pressure chamber 12. Therefore, even when using an ink containing 10 wt% (mass%) or more of solids, the viscosity increase of the ink can be suppressed. Thus, the present invention can be suitably applied to a liquid discharge head 1 and liquid discharge device 50 that use an ink containing 10 wt% (mass%) or more of solids. With the liquid discharge head 1 of Example 1, discharge stability can be maintained well regardless of the type of ink.

[0086] Furthermore, the operating temperature of the liquid ejection head 1 can be controlled by placing heaters around the entire tip to maintain a constant temperature. Since the viscosity of the ink changes with temperature, the ink viscosity at the head's operating temperature will affect the ejection stability.

[0087] In the liquid discharge head 1 of Example 1, the flow velocity of the circulating flow 27 that can be formed in the individual flow channels 23 by the second energy generating element 24 is several tens of mm / s to 1000 mm / s at instantaneous flow velocity. The flow velocity averaged over a time width of several hundred microseconds depends on the drive frequency of the second energy generating element 24. This is because the circulating flow 27 generated by the second energy generating element 24 is a transient flow that decays over time and stops after a certain period of time. When the drive frequency of the second energy generating element 24 is set to approximately 10 to 20 kHz, which is similar to the drive frequency (discharge frequency) of the first energy generating element 14, the average flow velocity of the circulating flow 27 that can be formed is several mm / s to 100 mm / s.

[0088] When using ink with a high pigment concentration, the ink viscosity increases at the nozzle 11 depending on the non-discharge time (rest time), which can change the discharge speed and reduce discharge stability. For example, ink with a viscosity of 3 cP to 6 cP at the head operating temperature can be considered ink with a high pigment concentration. When using such ink, it is preferable to circulate the ink while the rest time is short. Therefore, it is preferable to eliminate concentration by performing steady-state ink circulation or high-frequency transient ink circulation. In the liquid discharge head 1 of Example 1, transient ink circulation can be generated in the individual flow path 23 by driving the second energy generating element 24. Therefore, in the liquid discharge head 1 of Example 1, concentration at the nozzle 11 when using high-concentration ink can be eliminated by performing circulation at a high frequency.

[0089] When using ink with a low pigment concentration, the ejection speed may change depending on the non-ejection time (downtime), but this effect is relatively small compared to high-concentration ink. For example, ink with a viscosity of 1 cP or more but less than 3 cP at the head operating temperature can be considered low-pigment concentration ink. If the downtime is long, for example, the ink viscosity will increase at the ejection port 11 depending on the non-printing drive time (stop time). When restarting after being stopped for a certain period of time without printing, recovery operations such as suction, wiping, and preliminary ejection combined with these should be performed. This can suppress the effects of thickened ink, but these recovery processes involve waste ink.

[0090] In the liquid discharge head 1 of Example 1, by driving the second energy generating element 24, a circulating flow 27 is formed in the individual flow path 23, thereby eliminating concentration at the discharge port 11 and suppressing ink viscosity. Therefore, depending on the stop time, it is possible to avoid generating waste ink with recovery processing using only circulation. Furthermore, by combining recovery with circulation while performing circulating operations, and by combining this with suction operations for removing air bubbles inside the head, which are separate from the concentration elimination, it is possible to perform recovery processing that reduces waste ink.

[0091] Regardless of ink concentration, it is desirable to supply fresh ink near the discharge port 11 to suppress the effects of concentrated ink. When a circulating heater is used as the second energy generating element 24, the lower the effect of recirculation concentration, the greater the effect of ink circulation. Compared to a U-shaped ink circulation configuration, a straight-type ink circulation configuration exhibits a greater effect in maintaining discharge performance through ink circulation.

[0092] (Drive control) Figure 11 is a block diagram showing the control configuration of the liquid dispensing device 50 of Embodiment 1. The CPU 800 is a control unit that controls the operation of each part of the liquid dispensing device 50 based on a program such as a processing procedure stored in the ROM 301. The RAM 302 is used as a work area when the CPU 800 executes processing. The CPU 800 receives image data from an external host device 400 of the liquid dispensing device 50 and controls the liquid dispensing head 1 by controlling the head driver 1A based on the image data. The CPU 800 receives temperature information detected from the temperature sensor 53. The CPU 800 controls the driving of the first energy generating element 14 and the second energy generating element 24 of the liquid dispensing head 1 using the head driver 1A. In particular, the CPU 800 is a control means that controls the driving of the second energy generating element 24 based on the temperature detected by the temperature sensor 53.

[0093] The CPU 800 also controls the drivers of various actuators provided in the liquid dispensing device 50. For example, the CPU 800 controls the motor driver 303A of the carriage motor 303 for moving the carriage 60, the motor driver 304A of the transport motor 304 for transporting the recording medium P, and the pump driver 21A of the external pump 40. Although Figure 2 shows a configuration in which image data received from the host device 400 is processed, processing may also be performed in the liquid dispensing device 50 independently of data from the host device 400.

[0094] Figure 8 shows the control configuration of the liquid discharge head 1 of Embodiment 1. The substrate 18 of the liquid discharge chip 3 is provided with a controller 100, a selection drive circuit 200, an on / off drive circuit 240, a first energy generating element 14(An) (n=1~16), and a second energy generating element 24(Bn) (n=1~16). The liquid discharge chip 3 is connected to an external power supply 120 and an external circuit 110. The external circuit 110 includes the head driver 1A shown in Figure 11. The CPU 800 that controls the head driver 1A is a control means that controls the driving of the first energy generating element 14 and the second energy generating element 24.

[0095] The selective drive circuit 200 includes an on-on drive circuit 230 that selects between the first energy generating element 14 and the second energy generating element 24. The on-on drive circuit 230 responds to control signals at each address Nn (n=1 to 16) received from the controller 100 to turn on and drive either the first energy generating element 14 or the second energy generating element 24. The controller 100 controls the drive pulses for driving the first energy generating element 14 or the second energy generating element 24, and the time intervals at which these drive pulses are applied to each element.

[0096] The controller 100 controls the on / off drive circuit 240 based on the drive capability signal 300 for the second energy generating element 24. This controls the drive of the second energy generating element 24 when it is selected in the on-on drive circuit 230.

[0097] In this way, the on-on drive circuit 230 and the on-off drive circuit 240 control the drive of the second energy generating element 24.

[0098] If the drive feasibility signal 300 is a signal that does not drive the second energy generating element 24, the second energy generating element 24 will not be driven even if the on-on drive circuit 230 selects it. In this case, neither the first energy generating element 14 nor the second energy generating element 24 will be driven. On the other hand, if the first energy generating element 14 is selected in the on-on drive circuit 230, the first energy generating element 14 will be driven.

[0099] If the drive availability signal 300 is a signal to drive the second energy generating element 24, the second energy generating element 24 will be driven if the second energy generating element 24 is selected in the on-on drive circuit 230. If the first energy generating element 14 is selected, the first energy generating element 14 will be driven.

[0100] Therefore, the second energy generating element 24 is controlled according to the drive data and drive feasibility signal 300 of the first energy generating element 14. As a result, there is no need to provide drive data for the second energy generating element 24, and the amount of drive data can be reduced by half.

[0101] In the example shown in Figure 8, 16 sets (32 elements in total) of first energy generating elements 14 and second energy generating elements 24 are controlled as one group, but this is not the only configuration. For example, 8 sets (16 elements) or 12 sets (24 elements) of first energy generating elements 14 and second energy generating elements 24 may be controlled as one group. Furthermore, even when there are multiple second energy generating elements 24, a common drive / fail signal 300 can be used.

[0102] Figure 9 shows the liquid discharge head 1 of Example 1. Figure 9(a) shows the configuration near the discharge port 11 of the liquid discharge head 1 of Example 1, and is a diagram showing the main components when the liquid discharge head 1 is viewed in the Z direction. Figure 9(b) is a cross-sectional view of AA in Figure 9(a). Figure 9(c) is a cross-sectional view of AA in Figure 9(a), and is a cross-sectional view of the liquid discharge head 1 with a different configuration from Figure 9(b).

[0103] The liquid discharge head 1 of Example 1 has a first discharge port row 63a and a second discharge port row 63b, each consisting of a plurality of discharge ports 11 arranged in a first direction (Y direction). The second discharge port row 63b is provided alongside the first discharge port row 63a in a second direction (X direction) that intersects with the first direction (Y direction).

[0104] The liquid discharge head 1 has a plurality of first individual flow paths 23a that communicate with a plurality of discharge ports 11 of the first discharge port row 63a and extend in the X direction, and a plurality of second individual flow paths 23b that communicate with a plurality of discharge ports 11 of the second discharge port row 63b and extend in the X direction.

[0105] In the multiple first individual flow channels 23a and multiple second individual flow channels 23b, a first energy generating element 14 is provided at a position corresponding to the discharge port 11, which generates energy for discharging liquid from the discharge port 11. In the multiple first individual flow channels 23a and multiple second individual flow channels 23b, alongside the first energy generating element 14 in the X direction, energy for flowing the liquid is generated. A second energy generating element 24 is provided to generate -.

[0106] In the X direction, on the side opposite the second discharge port row 63b, with the first discharge port row 63a in between, a first flow path 71 is provided, through which one end 37a of a plurality of first individual flow paths 23a are connected. In the X direction, between the first discharge port row 63a and the second discharge port row 63b, a second flow path 72 is provided, through which the other ends 38a of a plurality of first individual flow paths 23a and one end 38b of a plurality of second individual flow paths 23b are connected. In the X direction, on the side opposite the first discharge port row 63a, with the second discharge port row 63b in between, a third flow path 73 is provided, through which the other ends 37b of a plurality of second individual flow paths 23b are connected.

[0107] The first channel 71 is provided with a plurality of first openings 22 arranged in the Y direction to allow liquid to flow in or out of the first channel 71. The second channel 72 is provided with a plurality of second openings 32 arranged in the Y direction to allow liquid to flow in or out of the second channel 72. The third channel 73 is provided with a plurality of third openings 42 arranged in the Y direction to allow liquid to flow in or out of the third channel 73.

[0108] The first energy generating element 14 provided in the first individual channel 23a and the first energy generating element 14 provided in the second individual channel 23b are both located close to the second opening 32. In addition, the second energy generating element 24 provided in the first individual channel 23a is located close to the first opening 22, and the second energy generating element 24 provided in the second individual channel 23b is located close to the third opening 42.

[0109] In each of the multiple first individual flow channels 23a, the second energy generating element 24 is positioned closer to the first flow channel 71 than the first energy generating element 14 in the X direction. Therefore, the flow resistance R1 between the second energy generating element 24 and the end of the first individual flow channel 23a on the first flow channel 71 side is smaller than the flow resistance R2 between the second energy generating element 24 and the end of the first individual flow channel 23a on the second flow channel 72 side.

[0110] In each of the multiple second individual flow channels 23b, the second energy generating element 24 is positioned closer to the third flow channel 73 in the X direction than the first energy generating element 14. Therefore, the flow resistance R1 between the second energy generating element 24 and the end of the second individual flow channel 23b on the third flow channel 73 side is smaller than the flow resistance R2 between the second energy generating element 24 and the end of the first individual flow channel 23a on the second flow channel 72 side.

[0111] Therefore, as explained in the example, in each of the multiple first individual flow paths 23a, the liquid flows from the first flow path 71 to the second flow path 72 due to the energy generated by the second energy generating element 24. Also, in each of the multiple second individual flow paths 23b, the liquid flows from the third flow path 73 to the second flow path 72 due to the energy generated by the second energy generating element 24. In other words, the circulating flow 27 flows from the second energy generating element 24 to the first energy generating element 14. As a result, a flow is generated that flows in from the first opening 22 and the third opening 42 and flows out to the second opening 32.

[0112] Let D1 be the size in the Y direction of the first non-opening portion 81 between two adjacent first openings 22, D2 be the size in the Y direction of the second non-opening portion 82 between two adjacent second openings 32, and D3 be the size in the Y direction of the third non-opening portion 83 between two adjacent third openings 42. The liquid discharge head 1 of Embodiment 1 is characterized in that D2 > D1 and D2 > D3. The first non-opening portion 81 between two adjacent first openings 22 is the portion between the closest Y-direction ends of adjacent first openings 22, and is the portion that forms a beam between the common flow path 29 and the first flow path 71 in the Z direction. The same applies to the second non-opening portion 82 and the third non-opening portion 83. In other words, a characteristic of Embodiment 1 is that the beam between the second openings 32 is larger than the beam between the first openings 22 and the beam between the third openings 42.

[0113] In Example 1, the first aperture 22, the second aperture 32, and the third aperture 42 are rectangles of substantially the same shape, and the number of first apertures 22 and third apertures 42 per unit length in the Y direction is equal. The number of second apertures 32 per unit length in the Y direction is less than the number of first apertures 22 and third apertures 42. For example, the second apertures 32 are arranged at a 150 dpi pitch, and the first apertures 22 and third apertures 42 are arranged at a 300 dpi pitch. In this case, D1 = D3.

[0114] A temperature sensor 53 is provided in the second non-opening portion 82. In Figure 9(a), the temperature sensor 53 is provided in multiple second non-opening portions 82 that are located at different positions in the Y direction, and a total of multiple temperature sensors 53 are provided. Note that a temperature sensor 53 may be provided in all of the second non-opening portions 82, in some of the second non-opening portions 82, or in just one of the second non-opening portions 82.

[0115] The CPU 800 controls the driving of the second energy generating element 24 based on the temperature detected by the temperature sensor 53. In Embodiment 1, multiple temperature sensors 53 are provided at different positions in the Y direction, and the CPU 800 controls the driving of the second energy generating element 24 located at a position corresponding to a temperature sensor 53 based on the temperature detected by that temperature sensor 53. The second energy generating element 24 located at a position corresponding to a temperature sensor 53 is, for example, a second energy generating element 24 located within a predetermined range in the ±Y direction with respect to the Y direction position of the temperature sensor 53.

[0116] The effects of the liquid discharge head 1 of Example 1 will now be explained. The liquid discharge head 1 is provided with multiple rows of multiple second energy generating elements 24 arranged in the Y direction. When the driving of each of these second energy generating elements 24 is controlled ON / OFF, a temperature distribution is generated within the liquid discharge chip 3 of the liquid discharge head 1. In the liquid discharge head 1 of Example 1, the temperature distribution within the liquid discharge chip 3 can be detected by the temperature sensor 53. The CPU 800 can adjust the number of times the second energy generating elements 24 are driven according to this temperature distribution within the chip. For example, when the temperature is low, the number of times the second energy generating elements 24 are driven is increased, and when the temperature is low, the number of times the second energy generating elements 24 are driven is decreased. That is, the higher the temperature detected by the temperature sensor 53, the fewer times the second energy generating elements 24 are driven. The fewer times the second energy generating elements 24 are driven, the less the thermal effect associated with driving the second energy generating elements 24 is reduced, thus suppressing the rise in chip temperature. Therefore, according to the liquid ejection head 1 of Example 1, an appropriate circulating flow 27 can be generated according to the temperature distribution inside the chip. This allows the second energy generating element 24 to be driven to eliminate ink concentration caused by the circulating flow 27, and also suppresses temperature unevenness inside the liquid ejection chip 3 caused by the heat generated by driving the second energy generating element 24.

[0117] Furthermore, since the temperature sensor 53 is located near the second energy generating element 24, it can accurately detect the temperature distribution caused by the operation of the second energy generating element 24. In addition, the size D2 of the second non-opening portion 82 in the Y direction is made larger than the sizes D1 and D2 of the first non-opening portion 81 and the third non-opening portion 83, providing space for the temperature sensor 53 between the two rows of second energy generating elements 24 extending in the Y direction. As a result, the number of temperature sensors 53 can be reduced compared to the case where a temperature sensor 53 is independently installed for each row of second energy generating elements 24.

[0118] By driving the second energy generating element 24, a circulating flow 27 is generated, which can eliminate ink concentration in the discharge port 11. To increase the effect of the circulating flow 27, it is effective to increase the number of times the second energy generating element 24 is driven. However, when the second energy generating element 24 is driven, unlike when the first energy generating element 14 is driven, the ink discharge This does not occur. As a result, the heat dissipation effect from ink ejection is small, heat tends to accumulate in the liquid ejection tip 3, and the temperature of the liquid ejection tip 3 tends to rise. When the temperature inside the liquid ejection tip 3 rises, the evaporation rate from the ejection port 11 increases, so ink concentration in the vicinity of the ejection port 11 tends to progress.

[0119] In this regard, the liquid ejection head 1 of Example 1, as described above, controls the driving of the second energy generating element 24 based on the temperature detected by the temperature sensor 53, thereby suppressing temperature unevenness caused by the heat generated by the driving of the second energy generating element 24. Therefore, even if the number of times the second energy generating element 24 is driven is increased, it is possible to suppress the progression of ink concentration while suppressing temperature unevenness.

[0120] Furthermore, the multiple second energy generating elements 24, which are arranged at each discharge port 11, can be individually controlled to be turned ON / OFF according to, for example, the degree of concentration at each discharge port 11. However, if the operation of the second energy generating elements 24 is individually controlled to be turned ON / OFF, a temperature distribution may occur within the liquid discharge tip 3 due to the heat generated by the operation of the second energy generating elements 24, potentially leading to large temperature unevenness.

[0121] In this regard, the liquid discharge head 1 of Example 1 can suppress temperature unevenness caused by heat generated by the driving of the second energy generating element 24 by controlling the driving of the second energy generating element 24 based on the temperature detected by the temperature sensor 53, as described above.

[0122] In recent years, due to increased productivity, chip lengths have been extended, and the distance between rows has been reduced to minimize costs. As a result, multi-color chips are prone to excessive temperature rise and temperature unevenness due to the effects of heat, as described above. Applying the liquid discharge head 1 of Example 1 to such multi-color chips is preferable because it can suppress temperature unevenness caused by heat.

[0123] The shape of the back side of the substrate 18 changes depending on the etching method used for the substrate 18. Figure 9(b) shows the configuration when a common channel 29 is formed on the substrate 18 by anisotropic etching of Si, and the first opening 22, second opening 32, and third opening 42 are formed by dry processing. Figure 9(c) shows the configuration when a common channel 29 is formed on the substrate 18 by dry etching of Si, and the first opening 22, second opening 32, and third opening 42 are further formed. The liquid discharge head 1 of Example 1 can be applied to any configuration having a substrate 18 of any shape and the above effects can be obtained.

[0124] Furthermore, wiring can be installed in the area (beam) between two adjacent first openings 22 and in the area (beam) between two adjacent third openings 42.

[0125] In the liquid discharge head 1 of Example 1, the Y-direction positions of the first opening 22 and the third opening 42 may be the same or different, as shown in Figure 9(a). For example, the Y-direction positions of the first opening 22 and the third opening 42 may be shifted to match the Y-direction positions of the discharge ports 11 in the first discharge port row 63a and the second discharge port row 63b. This also applies to other embodiments besides Example 1.

[0126] (Example 2) Figure 10 shows the liquid discharge head 1 of Example 2. Figure 10(a) shows the configuration near the discharge port 11 of the liquid discharge head 1 of Example 2, and is a diagram showing the main components when the liquid discharge head 1 is viewed in the Z direction. Figure 10(b) is a cross-sectional view AA of Figure 10(a).

[0127] The difference between Example 2 and Example 1 is that the second energy flow channel provided in the first individual flow channel 23a The energy generating element 24 and the second energy generating element 24 provided in the second individual channel 23b are both located close to the second opening 32. In addition, the first energy generating element 14 provided in the first individual channel 23a is located close to the first opening 22, and the first energy generating element 14 provided in the second individual channel 23b is located close to the third opening 42.

[0128] In each of the multiple first individual flow channels 23a, the second energy generating element 24 is positioned closer to the second flow channel 72 than the first energy generating element 14 in the X direction. Therefore, the flow resistance R1 between the second energy generating element 24 and the end of the first individual flow channel 23a on the second flow channel 72 side is smaller than the flow resistance R2 between the second energy generating element 24 and the end of the first individual flow channel 23a on the first flow channel 71 side.

[0129] In each of the multiple second individual flow channels 23b, the second energy generating element 24 is positioned closer to the second flow channel 72 in the X direction than the first energy generating element 14. Therefore, the flow resistance R1 between the second energy generating element 24 and the end of the second individual flow channel 23b on the second flow channel 72 side is smaller than the flow resistance R2 between the second energy generating element 24 and the end of the first individual flow channel 23a on the third flow channel 73 side.

[0130] Therefore, in each of the multiple first individual flow paths 23a, the energy generated by the second energy generating element 24 causes the liquid to flow from the second flow path 72 to the first flow path 71. Also, in each of the multiple second individual flow paths 23b, the energy generated by the second energy generating element 24 causes the liquid to flow from the second flow path 72 to the third flow path 73. In other words, the circulating flow 27 flows from the second energy generating element 24 to the first energy generating element 14. As a result, a flow is generated that flows in from the second opening 32 and out to the first opening 22 and the third opening 42. The points that D2 > D1 and D2 > D3 are the same as in Example 1.

[0131] The effects of the liquid discharge head 1 in Example 2 will now be explained. In Example 2, the second energy generating element 24 is positioned close to the second opening 32. Therefore, the temperature sensor 53 provided in the second non-opening portion 82 is positioned close to the second energy generating element 24. This makes it possible for the temperature sensor 53 to detect temperature changes due to heat generation by the second energy generating element 24 with greater accuracy. As a result, the temperature distribution within the chip can be detected with greater accuracy, and the drive control of the second energy generating element 24 based on the temperature detected by the temperature sensor 53 can be performed with greater accuracy. Therefore, temperature unevenness in the liquid discharge head 1 can be suppressed more reliably.

[0132] Furthermore, since the concentrated ink near the discharge port 11 is discharged by branching into the first channel 71 and the third channel 73 on both sides, the influence of the concentrated ink when it re-flows into the individual channels in response to discharge can be suppressed.

[0133] This embodiment includes the following configuration. (Composition 1) A liquid dispensing head having a dispensing port for dispensing liquid, A first discharge port row consisting of a plurality of discharge ports arranged in a first direction, A second discharge port row comprising a plurality of discharge ports arranged in the first direction, wherein the second discharge port row is provided alongside the first discharge port row in a second direction intersecting the first direction, A plurality of first individual flow paths are connected to each of the plurality of discharge ports of the first discharge port row and extend in the second direction, Multiple second individual flow paths are connected to each of the multiple discharge ports of the second discharge port row and extend in the second direction, The position corresponding to the discharge port in the plurality of first individual flow paths and the plurality of second individual flow paths. A first energy generating element is provided in the location and generates energy for discharging liquid from the discharge port, A second energy generating element is provided in the plurality of first individual channels and the plurality of second individual channels in the second direction, alongside the first energy generating element, and generates energy for causing the liquid to flow. A first flow path is provided in the second direction, on the opposite side of the second discharge port row, with the first discharge port row in between, and through which one end of the plurality of first individual flow paths communicates; A second flow path is provided between the first and second discharge port rows in the second direction, and the other end of the plurality of first individual flow paths and one end of the plurality of second individual flow paths are in communication with each other. A third flow path is provided in the second direction, on the opposite side of the first discharge port row, with the second discharge port row in between, and the other ends of the plurality of second individual flow paths are connected to it. A plurality of first openings arranged in the first direction provided in the first flow path, the first openings for allowing liquid to flow into or out of the first flow path, A plurality of second openings arranged in the first direction provided in the second flow path, the second openings for allowing liquid to flow into or out of the second flow path, A plurality of third openings arranged in the first direction and provided in the third flow path, the third openings for allowing liquid to flow into or out of the third flow path, It has, The size of the first non-opening portion between the two adjacent first openings in the first direction is D1. The size of the second non-opening portion between the two adjacent second openings in the first direction is D2. The size of the third non-opening portion between the two adjacent third openings in the first direction is D3. So, D2 > D1, D2>D3 And, A temperature sensor provided in the second non-opening portion, A control means for controlling the drive of the second energy generating element based on the temperature detected by the temperature sensor, A liquid dispensing head characterized by having the following features. (Configuration 2) The temperature sensor is provided in a plurality of the second non-opening portions that are located at different positions in the first direction. The liquid discharge head according to configuration 1, wherein the control means controls the driving of the second energy generating element located at a position corresponding to the second non-opening portion on which the temperature sensor is provided, based on the temperature detected by the temperature sensor. (Composition 3) The liquid discharge head according to configuration 1 or 2, wherein the control means reduces the number of times the second energy generating element is driven as the temperature detected by the temperature sensor increases. (Composition 4) A liquid dispensing head described in any one of configurations 1 to 3, where D1 = D3. (Composition 5) A liquid discharge head according to any one of configurations 1 to 4, wherein the number of second openings per unit length in the first direction is less than the number of first openings per unit length in the first direction and less than the number of third openings per unit length in the first direction. (Composition 6) In each of the plurality of first individual flow channels, the second energy generating element is provided at a position closer to the first flow channel than the first energy generating element in the second direction, and the flow resistance R1 between the second energy generating element and the end of the first individual flow channel closer to the first flow channel is smaller than the flow resistance R2 between the second energy generating element and the end of the first individual flow channel closer to the second flow channel. In each of the plurality of second individual channels, the second energy generating element is provided at a position closer to the third channel than the first energy generating element in the second direction, and the flow resistance R1 between the second energy generating element and the end of the second individual channel closer to the third channel is smaller than the flow resistance R2 between the second energy generating element and the end of the second individual channel closer to the second channel. In each of the plurality of first individual channels, the energy generated by the second energy generating element causes the liquid to flow in a direction from the end closer to the first channel toward the end closer to the second channel. A liquid discharge head according to any one of the configurations 1 to 5, wherein in each of the plurality of second individual flow paths, the liquid flows in a direction from the end closer to the third flow path toward the end closer to the second flow path due to the energy generated by the second energy generating element. (Composition 7) In each of the plurality of first individual flow channels, the second energy generating element is provided at a position closer to the second flow channel than the first energy generating element in the second direction, and the flow resistance R1 between the second energy generating element and the end of the first individual flow channel closer to the second flow channel is smaller than the flow resistance R2 between the second energy generating element and the end of the first individual flow channel closer to the first flow channel. In each of the plurality of second individual channels, the second energy generating element is provided at a position closer to the second channel than the first energy generating element in the second direction, and the flow resistance R1 between the second energy generating element and the end of the second individual channel closer to the second channel is smaller than the flow resistance R2 between the second energy generating element and the end of the second individual channel closer to the third channel. In each of the plurality of first individual channels, the energy generated by the second energy generating element causes the liquid to flow in a direction from the end closer to the second channel toward the end closer to the first channel. A liquid discharge head according to any one of the configurations 1 to 5, wherein in each of the plurality of second individual flow paths, the liquid flows in a direction from the end closest to the second flow path toward the end closest to the third flow path due to the energy generated by the second energy generating element. (Composition 8) The liquid discharge head according to any one of configurations 1 to 7, wherein the second energy generating element is an electrothermal conversion element. (Composition 9) The liquid discharge head according to configuration 6 or 7, wherein the second energy generating element is an electrothermal conversion element, and the ratio of the flow resistances R1 and R2, R1 / R2, is a value from 0.05 to 0.40. (Composition 10) The liquid discharge head according to any one of configurations 1 to 9, wherein the first energy generating element is an electrothermal conversion element. (Composition 11) The control means is a liquid discharge head according to any one of configurations 1 to 10, which controls the driving of a plurality of the second energy generating elements by a common control signal. (Composition 12) A liquid dispensing head as described in any one of items 1 to 11, A supply means for supplying liquid to the liquid discharge head, A liquid dispensing device equipped with the following features. [Explanation of symbols]

[0134] 1: Liquid discharge head, 11: Discharge port, 14: First energy generating element, 22: First opening, 23a: First individual flow path, 23b: Second individual flow path, 24: Second energy generating element, 32: Second opening, 42: Third opening, 53: Temperature sensor, 63a: First discharge port row, 63b: Second discharge port row, 71: First flow path, 72: Second flow path, 73: Third flow path, 81: First non-opening section, 8 2: 2nd non-opening part, 83: 3rd non-opening part, 800: CPU

Claims

1. A liquid dispensing head having a dispensing port for dispensing liquid, A first discharge port row consisting of a plurality of discharge ports arranged in a first direction, A second discharge port row comprising a plurality of discharge ports arranged in the first direction, wherein the second discharge port row is provided alongside the first discharge port row in a second direction intersecting the first direction, A plurality of first individual flow paths are connected to each of the plurality of discharge ports of the first discharge port row and extend in the second direction, Multiple second individual flow paths are connected to each of the multiple discharge ports of the second discharge port row and extend in the second direction, A first energy generating element is provided at a position corresponding to the discharge port in the plurality of first individual flow paths and the plurality of second individual flow paths, and generates energy for discharging liquid from the discharge port. A second energy generating element is provided in the plurality of first individual channels and the plurality of second individual channels in the second direction, alongside the first energy generating element, and generates energy for causing the liquid to flow. A first flow path is provided in the second direction, on the opposite side of the second discharge port row, with the first discharge port row in between, and through which one end of the plurality of first individual flow paths communicates, A second flow path is provided between the first and second discharge port rows in the second direction, and the other end of the plurality of first individual flow paths and one end of the plurality of second individual flow paths are in communication with each other. A third flow path is provided in the second direction, on the opposite side of the first discharge port row, with the second discharge port row in between, and the other ends of the plurality of second individual flow paths are connected to it. A plurality of first openings arranged in the first direction provided in the first flow path, the first openings for allowing liquid to flow into or out of the first flow path, A plurality of second openings arranged in the first direction and provided in the second flow path, the second openings for allowing liquid to flow into or out of the second flow path, A plurality of third openings arranged in the first direction and provided in the third flow path, the third openings being used to allow liquid to flow into or out of the third flow path, It has, The size of the first non-opening portion in the first direction between the two adjacent first openings is D1. The size of the second non-opening portion in the first direction between the two adjacent second openings is D2. The size of the third non-opening portion between the two adjacent third openings in the first direction is D3. So, D2 > D1, D2 > D3 And, A temperature sensor provided in the second non-opening portion, A control means for controlling the drive of the second energy generating element based on the temperature detected by the temperature sensor, A liquid dispensing head characterized by having the following features.

2. The temperature sensor is provided in a plurality of the second non-opening portions that are located at different positions in the first direction. The liquid dispensing head according to claim 1, wherein the control means controls the driving of the second energy generating element located at a position corresponding to the second non-opening portion on which the temperature sensor is provided, based on the temperature detected by the temperature sensor.

3. The liquid discharge head according to claim 1 or 2, wherein the control means reduces the number of times the second energy generating element is driven as the temperature detected by the temperature sensor increases.

4. A liquid dispensing head according to claim 1 or 2, wherein D1 = D3.

5. The liquid dispensing head according to claim 1 or 2, wherein the number of second openings per unit length in the first direction is less than the number of first openings per unit length in the first direction and less than the number of third openings per unit length in the first direction.

6. In each of the plurality of first individual flow channels, the second energy generating element is provided at a position closer to the first flow channel than the first energy generating element in the second direction, and the flow resistance R1 between the second energy generating element and the end of the first individual flow channel closer to the first flow channel is smaller than the flow resistance R2 between the second energy generating element and the end of the first individual flow channel closer to the second flow channel. In each of the plurality of second individual flow paths, the second energy generating element is provided at a position closer to the third flow path than the first energy generating element in the second direction, and the flow resistance R1 between the second energy generating element and the end of the second individual flow path closer to the third flow path is smaller than the flow resistance R2 between the second energy generating element and the end of the second individual flow path closer to the second flow path. In each of the plurality of first individual channels, the energy generated by the second energy generating element causes the liquid to flow in a direction from the end closer to the first channel toward the end closer to the second channel. The liquid discharge head according to claim 1 or 2, wherein in each of the plurality of second individual flow paths, the liquid flows in a direction from the end closer to the third flow path toward the end closer to the second flow path due to the energy generated by the second energy generating element.

7. In each of the plurality of first individual flow channels, the second energy generating element is provided at a position closer to the second flow channel than the first energy generating element in the second direction, and the flow resistance R1 between the second energy generating element and the end of the first individual flow channel closer to the second flow channel is smaller than the flow resistance R2 between the second energy generating element and the end of the first individual flow channel closer to the first flow channel. In each of the plurality of second individual flow paths, the second energy generating element is provided at a position closer to the second flow path than the first energy generating element in the second direction, and the flow resistance R1 between the second energy generating element and the end of the second individual flow path closer to the second flow path is smaller than the flow resistance R2 between the second energy generating element and the end of the second individual flow path closer to the third flow path. In each of the plurality of first individual channels, the energy generated by the second energy generating element causes the liquid to flow in a direction from the end closer to the second channel toward the end closer to the first channel. The liquid discharge head according to claim 1 or 2, wherein in each of the plurality of second individual flow paths, the liquid flows in a direction from the end closest to the second flow path toward the end closest to the third flow path due to the energy generated by the second energy generating element.

8. The liquid discharge head according to claim 1 or 2, wherein the second energy generating element is an electrothermal conversion element.

9. The liquid discharge head according to claim 6, wherein the second energy generating element is an electrothermal conversion element, and the ratio R1 / R2 of the flow resistances R1 and R2 is a value from 0.05 to 0.

40.

10. The liquid discharge head according to claim 1 or 2, wherein the first energy generating element is an electrothermal conversion element.

11. The control means controls the driving of the plurality of second energy generating elements by a common control signal. A liquid dispensing head according to claim 1 or 2.

12. A liquid dispensing head according to claim 1 or 2, A supply means for supplying liquid to the liquid discharge head, A liquid dispensing device equipped with the following features.

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