Liquid dispensing head and liquid dispensing device

Abstract

This invention provides a technology that can improve the circulation efficiency of a liquid discharge head that uses an energy generating element to circulate liquid. [Solution] A liquid discharge head comprising a liquid discharge section having a pressure chamber, a discharge port for discharging liquid from the pressure chamber, and an energy generating element that generates energy to discharge the liquid in the pressure chamber from the discharge port, and a circulation channel having an inlet into which liquid supplied to the pressure chamber flows in and an outlet out which liquid recovered from the pressure chamber flows out, with the pressure chamber positioned between the inlet and the outlet, wherein the liquid discharge head comprises a first electrothermal conversion element provided in the circulation channel on a side closer to the inlet than the energy generating element, and a second electrothermal conversion element provided in the circulation channel on a side closer to the inlet than the energy generating element and adjacent to the first electrothermal conversion element, and the first electrothermal conversion element and the second electrothermal conversion element are driven at different timings.

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 such as an inkjet recording head, ink (liquid) concentration is one of the factors that deteriorate image quality. In ejection ports where ejection is not performed for a while, evaporation of ink proceeds from the ejection ports, causing the ink to thicken. Variations in ejection volume and ejection direction result in streaks and density unevenness in the image, deteriorating the image quality.

[0003] In order to prevent ink concentration as described above, in recent years, a mechanism for circulating ink within a liquid ejection head has been proposed. By circulating the ink, it becomes possible to flush away the concentrated ink near the ejection port and supply fresh ink. In Patent Document 1, one energy generating element (energy generating element for ejection) for ejecting liquid and one electrothermal conversion element (energy generating element for circulation flow) for feeding the liquid in a circulation flow path including a pressure chamber are continuously arranged within the circulation flow path.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In Patent Document 1, the energy generating element for discharge and the energy generating element for circulating flow are arranged in a one-to-one ratio. However, as the density of the discharge port increases, the flow path width narrows, which limits the pump size. Furthermore, if the energy generating element for circulating flow is driven at a high frequency to increase the flow rate, and if the energy generating element for circulating flow is an electrothermal conversion element, localized heat generation can cause reboil (re-foaming), hindering foaming and reducing the pump's flow rate. Therefore, there are limitations on the frequency at which the energy generating element for circulating flow can be driven, which in turn limits the flow rate, and it is conceivable that the concentration at the discharge port will not be resolved.

[0006] The objective of the present invention is to provide a technology that can improve the circulation efficiency in a liquid discharge head configured to circulate liquid using an energy generating element. [Means for solving the problem]

[0007] To achieve the above objective, the liquid discharge head of the present invention is A liquid discharge unit having a pressure chamber, a discharge port for discharging liquid from the pressure chamber, and an energy generating element that generates energy to discharge the liquid in the pressure chamber from the discharge port, A circulation channel having an inlet through which liquid supplied to the pressure chamber flows in, and an outlet through which liquid recovered from the pressure chamber flows out, wherein the pressure chamber is positioned between the inlet and the outlet, In a liquid dispensing head equipped with, A first electrothermal conversion element is provided in the circulation channel on a side closer to the inlet than the energy generating element, In the circulation channel, a second electrothermal conversion element is provided on a side closer to the inlet than the energy generating element and adjacent to the first electrothermal conversion element, Equipped with, The first electrothermal conversion element and the second electrothermal conversion element are driven at different timings. It is characterized by being. [Effects of the Invention]

[0008] According to the present invention, in a liquid discharge head configured to circulate liquid using an energy generating element, the circulation efficiency can be improved. [Brief explanation of the drawing]

[0009] [Figure 1] Perspective view of an inkjet recording head [Figure 2] Perspective view of the recording element substrate in the comparative example, viewed from the side opposite the ejection port. [Figure 3] Diagram illustrating the recording element substrate of the first embodiment. [Figure 4] Perspective view of the recording element substrate of a modified example of the first embodiment, viewed from the side facing the discharge port. [Figure 5] Schematic diagram of the drive signal of the electrothermal conversion element of the first embodiment [Figure 6] Diagram illustrating the recording element substrate of the second embodiment. [Figure 7] Diagram illustrating the recording element substrate of the third embodiment. [Figure 8] Diagram illustrating the recording element substrate of the fourth embodiment. [Figure 9] Diagram illustrating the recording element substrate of the fifth embodiment. [Figure 10] Diagram illustrating the drive signal of the electrothermal conversion element in the sixth embodiment. [Figure 11] This is a control configuration diagram for a liquid dispensing device. [Modes for carrying out the invention]

[0010] The embodiments for carrying out this invention will be described in detail below with reference to the drawings, based on examples. However, the dimensions, materials, shapes, and relative arrangements of the components described in these embodiments should be appropriately modified depending on the configuration of the device to which the invention is applied and various conditions. In other words, the scope of this invention is not intended to be limited to the following embodiments.

[0011] In addition, although a plurality of features are described in each of the embodiments described below, not all of these plurality of features are essential to the invention, and the plurality of features may be arbitrarily combined. Further, in the accompanying drawings, the same reference numerals are assigned to the same or similar configurations among the embodiments, and redundant descriptions are omitted.

[0012] (First Embodiment)

[0013] (Description of Head Configuration) FIG. 1 is a perspective view of an inkjet recording head 100 (hereinafter also simply referred to as a recording head) that can be used as a liquid ejection head of the present invention. The recording head 100 according to the first embodiment of the present invention is used by being attached to a recording device using an inkjet recording method as a liquid ejection device. The recording device is, for example, a device that forms (records) characters, symbols, images, etc. by selectively ejecting a plurality of colored liquids from the recording head 100 and landing them on a recording medium. Note that any recording medium can be used as long as it can form an image by landing liquid droplets. For example, various materials and forms such as paper, cloth, the label surface of an optical disk, a plastic sheet, an OHP sheet, an envelope, etc. can be used as the recording medium. The liquid ejected by the liquid ejection head to which the present invention is applicable is typically ink, but is not limited thereto, and may be a reaction liquid or a pretreatment liquid replenished to the liquid ejection device. The recording head 100 is configured such that a plurality of recording element substrates 4 in which a plurality of recording elements are arranged in the Y direction are further arranged in the Y direction. Here, a full-line type recording head 100 is shown in which the recording element substrates 4 are arranged in the Y direction by a distance corresponding to the width of an A4 size.

[0014] Each of the recording element substrates 4 is connected to the same electric wiring board 1 via a flexible wiring board 101 It is connected to 02. On the electrical wiring board 102, a power supply terminal 103 for receiving power and a signal input terminal 104 for receiving the ejection signal sent from the CPU 800 (see FIG. 11) as a control unit are provided. On the other hand, in the ink supply unit 105, a circulation flow path is formed for supplying the ink supplied from an ink tank (not shown) to the individual recording element substrates 4 or recovering the ink not consumed in the recording.

[0015] Under the above configuration, each of the recording elements arranged on the recording element substrate 4 uses the power supplied from the power supply terminal 103 based on the ejection signal input from the signal input terminal 104, and ejects the ink supplied from the ink supply unit 105 in the Z direction in the figure.

[0016] FIG. 11 is a block diagram showing the control system of a recording apparatus 1000 in which the recording head 100 according to the present embodiment is used. The CPU 800 is a control unit that controls the operations of each part of the recording apparatus 1000 based on programs such as processing procedures stored in the ROM 301. The RAM 302 is used as a work area and the like when the CPU 800 executes processing. The CPU 800 receives image data from a host device 400 outside the recording apparatus 1000, and controls the head driver 100A based on the image data to control the driving of the elements provided in the recording head 100. The CPU 800 receives the temperature information detected from the temperature sensor 500. The CPU 800 controls the driving of various energy generating elements (electrothermal conversion elements) of the recording head 100 by the head driver 100A.

[0017] The CPU 800 also controls the drivers of various actuators provided in the recording device 1000. For example, the CPU 800 controls the motor driver 303A of the carriage motor 303, which moves the carriage that holds the recording head 100. In addition, the CPU 800 controls the motor driver 304A of the transport motor 304 for transporting the recording medium, the pump driver 210A of the external pump 210, and the like. Although Figure 11 shows a configuration in which image data received from the host device 400 is processed, processing may also be performed in the recording device 1000 without relying on data from the host device 400.

[0018] (Description of recording element) Figures 3(a) to 3(c) show enlarged views of a portion of the recording element substrate 4 of the recording head 100 shown in Figure 1, and are schematic diagrams showing a portion of the flow path near the discharge port in the first embodiment. Figure 3(a) is a schematic perspective view of the U-shaped flow path configuration, seen from the side (-Z direction) opposite the discharge port of the recording element substrate 4 of the liquid discharge head. Figure 3(b) is a cross-sectional view taken along arrow A in Figure 3(a). Figure 3(c) is a cross-sectional view taken along arrow B in Figure 3(a).

[0019] First, the layout configuration of the parts of the recording head 100 according to this embodiment will be described. Here, the first, second, and third directions used to define the layout of the parts of the recording head 100 are the Z direction, X direction, and Y direction, respectively, and in this embodiment, the three are configured to be orthogonal to each other, but the configuration is not limited to this. Within a range that does not affect the function of the recording head 100, for example, the Z direction, X direction, and Y direction may intersect each other at a slight angle.

[0020] The recording element substrate 4 constituting the recording head 100 according to this embodiment has a configuration that forms an ink ejection section 40 (liquid ejection section), and includes a pressure chamber 3, an ejection port 2, and an energy generating element 1 that generates energy to eject the ink in the pressure chamber from the ejection port 2. In this embodiment, the energy generating element 1 is composed of an electrothermal conversion element. Note that the energy generating element 1 is not limited to an electrothermal conversion element, and a piezoelectric element or the like may be used. The ink ejection section 40 is arranged in a circulation channel 7. The circulation channel 7 has an inlet 8 (supply channel) through which ink supplied to the ink ejection section 40 flows in, and an outlet 9 (discharge channel) through which ink recovered from the ink ejection section 40 flows out. The ink ejection section 40 flows through the inlet 8 and the circulation channel 7 It is located between Exit 9 and the exit.

[0021] The recording element substrate 4 further includes a first electrothermal conversion element 5 and a second electrothermal conversion element 6 as energy generating elements that generate energy to cause the ink in the circulation channel to flow. The first electrothermal conversion element 5 is provided in the circulation channel 7 on a side closer to the inlet 8 than the energy generating element 1, and the second electrothermal conversion element 6 is provided in the circulation channel 7 on a side closer to the inlet 8 than the energy generating element 1 and adjacent to the first electrothermal conversion element 5. In this embodiment, the second electrothermal conversion element 6 is provided in the circulation channel 7 on a side further from the inlet 8 than the first electrothermal conversion element 5.

[0022] As shown in Figure 3(a), the circulation channel 7 is a substantially U-shaped channel overall. The inlet 8 and outlet 9 are both located on one side of the ink ejection section 40 in the X direction (second direction), which intersects with the Z direction (first direction), which is the direction in which the ejection port 2 opens (ink ejection direction). Furthermore, the inlet 8 and outlet 9 are arranged to be aligned in the Y direction (third direction), which intersects with both the Z direction (first direction) and the X direction (second direction). The circulation channel 7 includes an upstream channel 71 extending from the inlet 8 from one side to the other in the X direction, and a downstream channel 72 extending from the upstream channel 71 in the opposite direction, from the other side to the one side in the X direction. The first electrothermal conversion element 5 and the second electrothermal conversion element 6 are located in the upstream channel 71, and the ink ejection section 40 is located in the downstream channel 72.

[0023] As shown in Figure 3(b), the recording element substrate 4 of this embodiment has a configuration in which a first substrate 17, a first flow channel member 13 (first flow channel forming member), and an orifice plate 16 are stacked in the Z direction in order. An energy generating element 1, which is an electrothermal conversion element, is arranged on the surface of the first substrate 17 in the cross-section viewed from arrow A, and an outlet 2 is formed at the position of the orifice plate 16 corresponding to the energy generating element 1.

[0024] As shown in Figure 3(c), a first electrothermal conversion element 5 and a second electrothermal conversion element 6 are arranged adjacent to each other on the surface of the first substrate 17 in the cross-section viewed from arrow B. The orifice plate 16 and the first substrate 17 form individual pressure chambers 3 for each discharge port 2 and energy generating element 1. The pressure chambers 3 have partitions between the multiple discharge ports 2 and energy generating elements 1 arranged in the Y direction. The energy generating element 1 generates heat based on the input drive signal, causing film boiling in the ink, and the growth energy of the generated bubbles causes the ink to be discharged from the discharge port 2.

[0025] Furthermore, the partition wall forming the pressure chamber 3 also forms part of the circulation channel 7 having a first electrothermal conversion element 5 and a second electrothermal conversion element 6 located in the Y direction. The first electrothermal conversion element 5 and the second electrothermal conversion element 6 may be the same size or different sizes. In such a U-shaped channel configuration, the electrothermal conversion elements and energy generation elements are arranged alternately in the direction of the discharge port row (Y direction).

[0026] The structure of the recording element substrate 4 in this embodiment will be described in more detail.

[0027] As shown in Figure 3(a), the recording element substrate 4 is provided with a common flow path 12 that communicates with the inlet 8 and outlet 9, respectively. Multiple ink ejection units 40 are provided so as to be aligned in the Y direction (third direction), and the common flow path 12 is a common flow path between the multiple ink ejection units 40. Multiple circulation flow paths 7 are provided corresponding to the multiple ink ejection units 40, and each has an upstream flow path 71 that extends in the X direction (second direction) between the multiple ink ejection units 40 so as to intersect with the row of multiple ink ejection units 40. The common flow path 12 is provided so as to extend in the Y direction on one side of the inlet 8 and outlet 9 in the X direction, and multiple ink ejection units It communicates with each of the multiple inlets 8 and multiple outlets 9 provided corresponding to the 40. The multiple energy generating elements 1 and multiple first electrothermal conversion elements 5, each provided corresponding to the multiple ink ejection units 40, are arranged to be alternately aligned in the Y direction (third direction).

[0028] As shown in Figures 3(b) and 3(c), the first substrate 17 has a first surface 171 on which the ink ejection section 40, circulation channel, and electrothermal conversion elements 5 and 6 are arranged. The first channel member 13 is a channel forming member laminated on the first surface 171 of the first substrate 17, and has a partition wall 130 that forms part of the circulation channel 7. The orifice plate 16, through which the ejection port 2 opens, is laminated on the side opposite to the first substrate 17 relative to the first channel member 13. The pressure chamber 3 and the circulation channel 7 are defined by the first surface 171 of the first substrate 17, the partition wall 130, and the orifice plate 16. The first substrate 17 has a through hole 173 that penetrates in the Z direction (first direction) between the first surface 171 of the first substrate 17 and its back surface, the second surface 172, on one side of the inlet 8 and outlet 9 in the X direction (second direction). The common flow path 12 is defined by the through hole 173, the flow path member 13, and the orifice plate 16.

[0029] As shown in Figure 3(a), the first electrothermal conversion element 5 and the second electrothermal conversion element 6 are arranged adjacent to each other in the X direction (second direction) at a different position from the energy generating element 1 in the Y direction (third direction). The partition wall 130 of the first flow channel member 13 has a first partition wall portion 131 that extends in the X direction to partition the spaces between the multiple circulation channels 7 corresponding to the multiple ink ejection sections 40 in the Y direction. The partition wall 130 also has a second partition wall portion 132 that extends in the X direction to partition the spaces between the energy generating element 1 and the first electrothermal conversion element 5 and the second electrothermal conversion element 6 in the Y direction within each circulation channel 7. One side surface of the second partition wall portion 132 in the Y direction forms part of the upstream channel 71, and the other side surface of the second partition wall portion 132 in the Y direction forms part of the downstream channel 72 and the pressure chamber 3.

[0030] Next, in this embodiment, a circulation channel 7 will be described which supplies ink from an inlet 8 to a pressure chamber 3 as shown in Figure 3(a) and discharges it through an outlet 9 to a common channel 12. As a mechanism for generating flow within the circulation channel 7, a first electrothermal conversion element 5 and a second electrothermal conversion element 6 are placed between the inlet 8 and the energy generating element 1.

[0031] In this embodiment, the principle of the circulation method using an electrothermal conversion element will be explained. When the ink is heated by the electrothermal conversion element, bubbles grow due to the boiling of the ink film. At this time, within the circulation channel 7, the electrothermal conversion elements 5 and 6 are located closer to the inlet 8 than to the outlet 9, and the first flow resistance R1 between the electrothermal conversion elements 5 and 6 and the inlet 8 is smaller than the second flow resistance R2 between the electrothermal conversion elements 5 and 6 and the outlet 9. Therefore, the bubbles generated by the boiling of the ink film grow larger on the supply channel side where the flow resistance is smaller. Next, during the bubble contraction process, ink flows in to compensate for the volume lost due to contraction, so the flow of ink from the supply channel side where the bubbles grew larger becomes larger than the flow from the discharge channel side. Therefore, as shown in Figure 3(a), a flow occurs from the supply channel side to the discharge channel side, and the ink circulates.

[0032] Under the above configuration, when the ink in the pressure chamber 3 is consumed by the ejection operation, new, unconcentrated, fresh ink is supplied to the ejection port 2. Furthermore, even when the ejection operation is not taking place, ink is circulated in the circulation channel 7, and fresh ink is supplied to the ejection port 2. In this case, it is desirable to provide a filter 14 to prevent foreign matter and air bubbles from entering the channel and the ejection port 2. By placing a filter 14 not only at the inlet of the inlet 8 into which ink flows into the circulation channel 7, but also on the outlet 9 side, it is possible to prevent foreign matter from entering when ink is supplied from the outlet 9 (discharge channel) during the ejection operation.

[0033] The magnitude of this circulating flow is influenced by the ratio of flow resistances R1 and R2, and the size of the bubbles. In this embodiment, when the energy generating element for forming the circulating flow is an electrothermal conversion element, it is preferable to set the flow resistance ratio R1 / R2 between 0.05 and 0.4. By setting the flow resistance ratio R1 / R2 within the above range, it is possible to increase the circulating flow in the circulating channel 7. In this embodiment, the electrothermal conversion elements 5 and 6 are arranged adjacent to each other in the cross-section viewed by arrow B, but this is not limited to this arrangement, as long as the resistance relationship before and after the electrothermal conversion elements 5 and 6 is maintained.

[0034] Here, the adjustment of the flow resistance ratio R1 / R2 is not limited to a specific method, but for example, it may be adjusted by changing the positions of the electrothermal conversion elements 5 and 6 in the circulation channel 7. That is, for example, the magnitude of the flow resistances R1 and R2 can be changed by changing the flow channel distance between the electrothermal conversion elements 5 and 6 and the inlet 8, and the flow channel distance between the electrothermal conversion elements 5 and 6 and the outlet 9. Alternatively, the flow channel cross-section on both sides of the electrothermal conversion elements 5 and 6 may be changed, or both the flow channel distance and the flow channel cross-section may be changed. As a method of changing the flow channel cross-section, for example, a structure that obstructs flow may be placed on the flow channel to change the flow resistances R1 and R2.

[0035] (Explanation of drive signals) The circulating flow decays over time and eventually stops after a certain period. Therefore, in order to generate a continuous circulating flow, it is necessary to repeatedly drive the electrothermal conversion element for circulating flow formation. The driving cycle of the electrothermal conversion element for circulating flow formation is not particularly limited, as long as it is sufficient to discharge the concentrated ink in the discharge port 2.

[0036] Normally, increasing the driving frequency of the electrothermal conversion element for circulating flow and shortening the foaming cycle improves the efficiency of discharging concentrated ink. However, if the frequency is too high, problems such as re-boiling may occur, thus imposing constraints on the driving frequency. Therefore, in this embodiment, two electrothermal conversion elements, a first electrothermal conversion element 5 and a second electrothermal conversion element 6, are provided as electrothermal conversion elements for circulating flow, and by driving them at different timings, it is possible to improve circulation efficiency by interpolating the driving between them. In this embodiment, the first electrothermal conversion element 5 is positioned as the main element in the most effective position within the range of flow resistance ratio R1 / R2 of 0.05 to 0.4, and the second electrothermal conversion element 6 is positioned as a sub-element adjacent to the first electrothermal conversion element 5, as shown in Figure 3(a).

[0037] Furthermore, as shown in the modified example in Figure 4, the second electrothermal conversion element 6 may be placed on the supply channel side.

[0038] Furthermore, regarding the size of the first electrothermal conversion element 5 and the second electrothermal conversion element 6, it is preferable that they be the same size since the same voltage pulse can be applied to them. Also, even when changing the size to suppress the total power consumed by multiple electrothermal conversion elements, it is better to design them so that the width of the electrothermal conversion elements in the flow path width direction is the same.

[0039] The timing of the drive signals is shown in Figure 5(c). Figure 5(c) shows the drive signals for the first electrothermal conversion element 5 and the second electrothermal conversion element 6. In this case, the discharge pulse is paused before driving the electrothermal conversion elements 5 and 6. As mentioned above, the first electrothermal conversion element 5 is positioned in the optimal location to achieve the highest flow rate. If the first electrothermal conversion element 5 and the second electrothermal conversion element 6 are driven at the same timing in this configuration, the foaming by the second electrothermal conversion element 6 may change the flow resistance ratio before and after the first electrothermal conversion element 5, potentially reducing the flow rate. Therefore, the first electrothermal conversion element 5 and the second electrothermal conversion element 6 are driven alternately at different timings. The drive frequencies of the voltage pulses applied to the first electrothermal conversion element 5 and the second electrothermal conversion element 6 may be the same or different.

[0040] (effect) Referring to Figures 2 and 5(a) to 5(c), the configuration of the comparative example will be described for comparison with this embodiment. Figure 2 shows a perspective view of the U-shaped flow path configuration of the recording element substrate 4x of the comparative example, in which one electrothermal conversion element 5 is arranged for one discharge port 2, as seen from the side facing the discharge port 2 (-Z direction). Figure 5(a) shows the timing of the drive signal for the voltage pulse applied to the energy generation element 1 in the comparative example. In Figure 5(a), time t is taken on the horizontal axis, and the drive timing f of the voltage pulse represents the drive frequency, which is expressed as the reciprocal of time t (the same applies hereafter). Consider the case where the electrothermal conversion element 5 is placed in the optimal position where the flow rate is greatest, and is driven at an appropriate drive frequency (for example, f1=15kHz, f2=15kHz in Figure 5(a)) that does not affect foaming due to localized heat generation.

[0041] In the case shown in Figure 5(a), where only the first electrothermal conversion element 5, which is positioned at the optimal location for the greatest flow rate, is driven, the flow rate can be increased compared to the case shown in Figure 5(c), where the two electrothermal conversion elements 5 and 6 are driven alternately, as in this embodiment. This is because, in this embodiment, the flow rate of the secondary second electrothermal conversion element 6 is slightly lower than that of the first electrothermal conversion element 5.

[0042] On the other hand, if a higher flow rate is required, and only the first electrothermal conversion element 5 is driven at f1, for example, 30 kHz, as shown in Figure 5(b), localized heat generation in the electrothermal conversion element section will increase. As a result, there is a concern that foaming will be hindered, ultimately leading to a reduction in the pump's flow rate.

[0043] Figure 5(c) shows the drive timing of the voltage pulses applied to the electrothermal conversion elements 5 and 6 of this embodiment, in contrast to the comparative example described above. For example, the drive frequency f1 of the first electrothermal conversion element 5 is set to 15 kHz, and the drive frequency f2 of the second electrothermal conversion element 6 is set to 15 kHz, with the second electrothermal conversion element 6 being driven with a half-cycle delay from the first electrothermal conversion element 5. In this case, the frequency F1 between the first electrothermal conversion element 5 and the second electrothermal conversion element 6 becomes 30 kHz. Therefore, the temperature rise of the ink due to localized heat generation when one electrothermal conversion element is driven at a high frequency can be suppressed by driving the two electrothermal conversion elements in a dispersed manner. Furthermore, by repeatedly driving the two electrothermal conversion elements alternately with a timing delay, the flow rate can be increased, allowing fresh ink to flow to the nozzle, thereby suppressing viscosity buildup in the nozzle.

[0044] (Second Embodiment) Referring to Figures 6(a) and 6(b), only the differences between the recording element substrate 4c of the first embodiment and the cyclic configuration of the recording element substrate 4c in the second embodiment of the present invention will be described. In the second embodiment, matters not specifically described here are the same as in the first embodiment.

[0045] (Description of recording element) Figure 6(a) is a perspective view of a portion of the flow path near the discharge port of the recording element substrate 4c in this embodiment, viewed from the side opposite the discharge port (-Z direction). In contrast to the first embodiment, in which the first electrothermal conversion element 5 and the second electrothermal conversion element 6 are arranged adjacent to each other, this embodiment has a configuration in which the first electrothermal conversion element 5, the second electrothermal conversion element 6, and the third electrothermal conversion element 10 are arranged side by side.

[0046] In this embodiment, similar to the first embodiment, the first electrothermal conversion element 5 is positioned as the main element, and the second electrothermal conversion element 6 and the third electrothermal conversion element 10 are positioned as sub-elements, as shown in Figure 6(a). In this embodiment, as shown in Figure 6(a), the first electrothermal conversion element 5 is positioned in the central part, and the second electrothermal conversion element 6 and the third electrothermal conversion element 10 are positioned adjacent to it. Specifically, the third electrothermal conversion element 10 is positioned in the circulation channel 7, and is positioned more towards the energy generating element 1. It is located on the side closer to the inlet 8 and adjacent to the first electric heat conversion element 5, on the opposite side from the second electric heat conversion element 6. In other words, the third electric heat conversion element 10 is positioned in the circulation channel 7 closer to the inlet 8 than the first electric heat conversion element 5 and the second electric heat conversion element 6 (the closest of the three electric heat conversion elements). The arrangement order of the first electric heat conversion element 5, the second electric heat conversion element 6, and the third electric heat conversion element 10 is not limited to this, as long as the resistance relationship between the front and back of the electric heat conversion elements is maintained.

[0047] (Explanation of drive signals) Figure 6(b) shows the driving timing of the voltage pulses applied to the three electrothermal conversion elements 5, 6, and 10. In this embodiment, the first to third electrothermal conversion elements 5, 6, and 10 are driven at different timings from each other, and the three electrothermal conversion elements 5, 6, and 10 are repeatedly driven in order to generate a steady-state circulating flow, similar to the first embodiment. For example, the three electrothermal conversion elements 5, 6, and 10 are repeatedly driven in this order.

[0048] (effect) As shown in Figure 6(b), for example, the driving frequencies f1, f2, and f3 of the first, second, and third electrothermal conversion elements 5, 6, and 10 are set to 10 kHz, and the first electrothermal conversion element 5 is driven first, followed by the second electrothermal conversion element 6 and the third electrothermal conversion element 10, each with a 1 / 3 period difference. In this case, the frequency F1 between the first electrothermal conversion element 5 and the second electrothermal conversion element 6, and the frequency F2 between the second electrothermal conversion element 6 and the third electrothermal conversion element 10 are F1=F2=30 kHz. This makes it possible to further increase the flow rate compared to the first embodiment where the two electrothermal conversion elements 5 and 6 are driven alternately, and localized heat generation can be suppressed because they are driven in a distributed manner. With this configuration, there are constraints on the number of electrothermal conversion elements that can be arranged due to the size of the electrothermal conversion elements, the length of the circulation channel, the distance between the discharge port rows, etc., but it is possible to improve the circulation efficiency within the circulation channel.

[0049] (Third embodiment) Three-dimensional flow channel configuration Referring to Figures 7(a) to 7(c), only the differences between the recording element substrate 4d in the third embodiment of the present invention and the recording element substrates of the first and second embodiments will be described. In the third embodiment, matters not specifically described here are the same as in the above embodiments.

[0050] (Description of recording element) Figures 7(a) to 7(c) show the flow path configuration and wiring near the discharge port of the recording element substrate 4d in the third embodiment. Figures 7(a) and 7(b) are perspective views of the recording element substrate 4d viewed from the side facing the discharge port (-Z direction), and Figure 7(c) is a cross-sectional view taken along arrow C in Figures 7(a) and 7(b). Figure 7(a) shows the configuration from the orifice plate 16 to the first flow path member 13, and Figure 7(b) shows the configuration from the first substrate 17 to the second substrate 18.

[0051] As shown in Figure 7(c), the recording element substrate 4d of this embodiment has a configuration in which a second substrate 18, a second flow channel member 15 (second flow channel forming member), a first substrate 17, a first flow channel member 13, and an orifice plate 16 are stacked in the Z direction in order. An energy generating element 1, which is an electrothermal conversion element, is arranged on the surface (first surface 171) of the first substrate 17, and an outlet 2 is formed at the position of the orifice plate 16 corresponding to the energy generating element 1. Between the orifice plate 16 and the first substrate 17, the first flow channel member 13 forms individual pressure chambers 3 for each outlet 2 and energy generating element 1. The pressure chambers 3 have partitions between the multiple outlets 2 and energy generating elements 1 arranged in the Y direction.

[0052] The structure of the recording element substrate 4d in this embodiment will be described in more detail.

[0053] As shown in Figure 7(c), the circulation channel 7d of the recording element substrate 4d has a substantially U-shaped channel when viewed in the Y direction (third direction). The inlet 8 and outlet 9 are aligned in the Z direction (first direction), which is the opening direction of the ejection port 2 (ink ejection direction), and are both located on one side of the ink ejection section 40 in the X direction (second direction). The circulation channel 7d has an upstream channel 71d extending from the inlet 8 from one side to the other in the X direction, and a downstream channel 72d extending from the upstream channel 71d in the opposite direction, from the other side to the one side in the X direction. The electrothermal conversion elements 5 and 6 are located in the upstream channel 71d, and the ink ejection section 40 is located in the downstream channel 72d. That is, the ink ejection section 40 and the electrothermal conversion elements 5 and 6 are located at different positions in the Z direction.

[0054] As shown in Figures 7(a) and 7(b), multiple ink ejection units 40 are provided aligned in the Y direction, and the upstream flow path 71d and the downstream flow path 72d each extend in the X direction and are arranged to align in the Z direction, as shown in Figure 7(c). The common flow path 12 is provided on one side of the inlet 8 and outlet 9 in the X direction, extending in the Y direction, and communicates with each of the multiple inlet 8 and multiple outlet 9 provided corresponding to the multiple ink ejection units 40.

[0055] As shown in Figures 7(a) to 7(c), the multiple circulation channels 7d (upstream channel 71d, downstream channel 72d) provided corresponding to the multiple ink ejection sections 40 are arranged to be aligned in the Y direction. As shown in Figure 7(a), the multiple energy generating elements 1 provided corresponding to the multiple ink ejection sections 40 are also arranged to be aligned in the third direction. As shown in Figure 7(b), the multiple first electrothermal conversion elements 5 and the multiple second electrothermal conversion elements 6 provided corresponding to the multiple ink ejection sections 40 are each arranged to be aligned in the Y direction.

[0056] As shown in Figure 7(c), the first substrate 17 has a first surface 171 on which the ink ejection section 40 is arranged and which forms part of the downstream flow path 72d and the pressure chamber 3, and a second surface 172 which is the back surface of the first surface 171 and forms part of the upstream flow path 71d. The first substrate 17 further has a connection hole 174 that penetrates in the Z direction between the first surface 171 and the second surface 172 and forms a through-flow channel 11 (connecting channel) that connects the upstream flow path 71d and the downstream flow path 72d in the circulation flow path 7d.

[0057] The first flow channel member 13 is laminated on the first surface 171 of the first substrate 17, forming the downstream flow channel 72d and a part of the pressure chamber 3. The orifice plate 16, through which the discharge port 2 opens, is laminated on the side opposite to the first substrate 17 relative to the first flow channel member 13, forming the downstream flow channel 72d and a part of the pressure chamber 3. The second flow channel member 15 is laminated on the second surface 172 of the first substrate 17, forming a part of the upstream flow channel 71d. The second substrate 18 is laminated on the side opposite to the first substrate 17 relative to the second flow channel member 15, with the first electrothermal conversion element 5 and the second electrothermal conversion element 6 arranged on the side facing the second flow channel member 15, and forming a part of the upstream flow channel 71d.

[0058] The common channel 12 is formed by a common hole that sequentially penetrates the first channel member 13, the first substrate 17, the second channel member 15, and the second substrate 18 in the Z direction, on one side of the inlet 8 and outlet 9 in the X direction.

[0059] Next, in this embodiment, the circulation channel 7d that supplies ink to the pressure chamber 3 and discharges it to the common channel 12 will be described. As shown in Figure 7(c), the second substrate 18, the second channel member 15, the first substrate 17, the first channel member 13, and the orifice plate 16 each act as walls, forming individual circulation channels 7d in each recording element substrate 4d. The circulation channel 7d is composed of an upstream channel 71d, a through channel 11, and a downstream channel 72d. The upstream channel 71d is formed between the first substrate 17 and the second substrate 18 by the second channel member 15. Through channel 1 1 is formed by the connection hole 174 of the first substrate 17. The downstream flow path 72d is formed between the first substrate 17 and the orifice plate 16 by the first flow path member 13. Ink that flows from the common flow path 12 into the circulation flow path 7d via the inlet 8 is supplied to the pressure chamber 3 via the upstream flow path 71d and the through flow path 11. Ink that is recovered from the pressure chamber 3 without being used for discharge is discharged from the downstream flow path 72d to the common flow path 12 from the outlet 9.

[0060] As a mechanism for generating flow within the circulation channel 7d, a first electrothermal conversion element 5 and a second electrothermal conversion element 6 are arranged in the middle of the circulation channel 7d. The electrothermal conversion elements 5 and 6 are located on the surface of the second substrate 18, opposite to the second surface 172, which is the back surface of the first substrate 17 that is opposite to the surface on which the energy generating element 1 is arranged.

[0061] In this embodiment, the first electrothermal conversion element 5 is positioned as the main element at the most effective location within the range of a flow-resistivity ratio R1 / R2 of 0.05 to 0.4, and the second electrothermal conversion element 6 is positioned as a sub-element on the same second substrate 18 as the first electrothermal conversion element 5. The arrangement of the first electrothermal conversion element 5 and the second electrothermal conversion element 6 is not limited to this configuration; they may also be positioned on the first substrate 17 as long as a predetermined resistance relationship is maintained before and after the electrothermal conversion elements 5 and 6 in the circulation channel 7d. Furthermore, although two electrothermal conversion elements are arranged in the circulation channel in this embodiment, three or more electrothermal conversion elements may be arranged as in the second embodiment.

[0062] Furthermore, the flow direction of the circulation channel 7d is illustrated by an arrow in Figure 7(c). If the ink discharge direction at the discharge port 2 is from bottom to top, the flow direction of the circulation channel 7d will be from bottom to top within the through channel 11, and the ink supplied from the through channel 11 to the pressure chamber 3 will flow through the outlet 9 to the common channel 12.

[0063] Under the above configuration, when the ink in the pressure chamber 3 is consumed by the ejection operation, new, unconcentrated, fresh ink is supplied to the ejection port 2. Furthermore, even when the ejection operation is not taking place, ink is circulated within the circulation channel, and fresh ink is supplied to the ejection port 2.

[0064] (effect) In the configuration of this embodiment described above, when the direction in which the ink is discharged from the discharge port is from bottom to top, the electrothermal conversion elements 5 and 6 are positioned below the energy generating element 1. Furthermore, the electrothermal conversion elements 5 and 6 are located on the surface of the second substrate 18, opposite the back surface (second surface 172) of the surface on which the energy generating element 1 of the first substrate 17 is located. In planar U-shaped flow path configurations along the X and Y directions, as in the first and second embodiments, the inlet 8 and outlet 9 are located close together, leaving concerns about recirculation and concentration. However, in the configuration of this embodiment, by creating a three-dimensional configuration in the Z direction, the distance between the inlet 8 and outlet 9 can be increased, making it possible to suppress recirculation and concentration even when the driving frequency of the electrothermal conversion elements 5 and 6 is increased and the flow rate is increased.

[0065] Furthermore, this configuration makes it possible to increase the resolution of the recording element substrate 4d, as it is less affected by the resolution of the arrangement of the electrothermal conversion elements 5 and 6. Additionally, by making the circulation channels 7d separate, the flow velocity can be increased, thereby improving the energy efficiency of the electrothermal conversion elements 5 and 6 and enabling efficient circulation.

[0066] (Fourth Embodiment) Referring to Figures 8(a) to 8(c), only the differences between the recording element substrate 4e in the fourth embodiment of the present invention and the recording element substrates of the first to third embodiments will be described. In the fourth embodiment, matters not specifically described here are the same as in the above embodiments.

[0067] Figures 8(a) to 8(c) show some of the flow paths near the ejection port of the recording element substrate 4e in this embodiment. Figure 8(a) is a perspective view of the recording element substrate 4e from the side facing the ejection port (-Z direction). Figures 8(b) and 8(c) are cross-sectional views taken along arrow C in Figure 8(a).

[0068] An energy generating element 1, which is an electrothermal conversion element, is arranged on the surface (first surface 171) of the first substrate 17, and a discharge port 2 is formed at the position of the orifice plate 16 corresponding to the energy generating element 1. Also on the surface of the first substrate 17, a first electrothermal conversion element 5 and a second electrothermal conversion element 6 are arranged adjacent to the energy generating element 1 in a direction perpendicular to the Y direction of the discharge port row. The pressure chamber 3 has a partition wall between the multiple discharge ports 2 and the energy generating element 1, which are arranged in the Y direction. The partition wall forming the pressure chamber 3 extends in a direction perpendicular to the Y direction, which is the direction of the arrangement of the multiple discharge ports 2, and forms a circulation channel 7e including the first electrothermal conversion element 5 and the second electrothermal conversion element 6. The supply-side through-channel 21, which communicates with the inlet 8, is formed to penetrate the first substrate 17. Similarly, the discharge-side through-channel 22, which communicates with the outlet 9, is also formed to penetrate the first substrate 17.

[0069] The structure of the recording element substrate 4e in this embodiment will be described in more detail.

[0070] As shown in Figure 8(a), in this embodiment, the circulation channel 7e is configured to extend substantially linearly along the X direction (second direction). The inlet 8 is located on one side of the pressure chamber 3 in the X direction, and the outlet 9 is located on the other side of the pressure chamber 3 in the X direction. That is, the circulation channel 7e is a channel that extends in the X direction such that the inlet 8, pressure chamber 3, and outlet 9 are aligned in this order in the X direction. The electrothermal conversion elements 5 and 6 are positioned in the circulation channel 7e closer to the inlet 8 than the energy generating element 1.

[0071] As shown in Figure 8(a), the ink ejection units 40 are arranged in a plurality of alignments in the Y direction (third direction), and correspondingly, the circulation channels 7e are also arranged in a plurality of alignments in the Y direction. The plurality of energy generating elements 1 corresponding to the plurality of ink ejection units 40 are also aligned in the Y direction, and the plurality of first electrothermal conversion elements 5 and the plurality of second electrothermal conversion elements 6 are also aligned in the Y direction. The plurality of inlets 8 corresponding to the plurality of circulation channels 7e are also aligned in the Y direction, and the plurality of outlets 9 are also aligned in the Y direction.

[0072] As shown in Figure 8(b), the multiple inlets 8 and multiple outlets 9 are configured to communicate with each other through channels consisting of a supply-side through-channel 21, an outlet-side through-channel 22, and a common channel 12. The supply-side through-channel 21 is formed on one side of the first substrate 17 in the X direction from the inlet 8 (outside the inlet 8) by a through-hole that penetrates in the Z direction between the first surface 171 and the second surface 172. The outlet-side through-channel 22 is formed on the other side of the first substrate 17 in the X direction from the outlet 9 (outside the outlet 9) by a through-hole that penetrates in the Z direction between the first surface 171 and the second surface 172. The common channel 12 is formed on the side of the second surface 172 of the first substrate 17 so as to communicate with the supply-side through-channel 21 and the outlet-side through-channel 22, respectively. The common flow path 12 is defined by the second surface 172 of the first substrate 17 and the second flow path member 19 laminated thereon, and communicates with each of the multiple circulation flow paths 7e via the supply-side through-flow path 21 and the discharge-side through-flow path 22.

[0073] As shown in Figure 8(a), the supply-side through-flow channel 21 communicates with each of the multiple inlets 8 provided corresponding to the multiple ink ejection units 40, and the discharge-side through-flow channel 22 communicates with each of the multiple outlets 9 provided corresponding to the multiple ink ejection units 40.

[0074] As shown in Figure 8(b), the first flow channel member 13, which is laminated on the first surface 171 of the first substrate 17, is located between a plurality of energy generating elements 1 that are aligned in the Y direction corresponding to a plurality of ink ejection units 40. It has multiple partition walls 133 extending in the X direction. The pressure chamber 3 and the circulation channel 7e are defined by an orifice plate 16, which has an opening 2 and is laminated on the side opposite to the first substrate 17 relative to the first flow channel member 13, the first surface 171 of the first substrate 17, and the partition walls 133.

[0075] Furthermore, the supply-side through-flow channel 21 and the discharge-side through-flow channel 22 may be formed by a second flow channel member 19 and shared by a common flow channel 12 extending in the direction of the discharge port row (Y direction), as shown in Figure 8(b). In order to ensure refilling to the discharge port 2, it is necessary to minimize the effect of pressure loss, so it is preferable to make the first substrate 17 thin. However, in order to suppress the effect of recirculation concentration, as shown in Figure 8(b), the first substrate 17 may be made thicker to lengthen the paths of the supply-side through-flow channel 21 and the discharge-side through-flow channel 22.

[0076] Alternatively, as shown in Figure 8(c), a common supply channel 24 and a common discharge channel 25 may be formed in the second channel member 19 laminated on the second surface 172 of the first substrate 17, respectively, and these channels may be made common and communicate with each other outside the recording head. The common supply channel 24 is formed to extend in the direction of the discharge port row (Y direction) and communicates with each of the multiple circulation channels 7e via the supply through channel 21. Similarly, the common discharge channel 25 is formed to extend in the direction of the discharge port row and communicates with each of the multiple circulation channels 7e via the discharge through channel 22. By separating the channels provided in the second channel member 19 into a common supply channel 24 and a common discharge channel 25, a greater effect of suppressing recirculation concentration can be expected.

[0077] Next, in this embodiment, the circulation channel 7e that supplies ink from the supply-side through-channel 21 shown in Figure 8(a) to the pressure chamber 3 and discharges the ink through the discharge-side through-channel 22 will be described. As a mechanism for generating flow in the circulation channel e7, a first electrothermal conversion element 5 and a second electrothermal conversion element 6 are placed between the inlet 8 and the energy generating element 1. In this embodiment, according to the principle of the circulation method using electrothermal conversion elements as energy generating elements for forming a circulating flow, as shown in Figures 8(a) and 8(b), a flow is generated in the circulation channel 7e from the inlet 8 side to the outlet 9 side, and the ink circulates.

[0078] In this embodiment, as shown in Figures 8(a) to 8(c), the first electrothermal conversion element 5 is positioned closer to the energy generating element 1 than the second electrothermal conversion element 6, but the configuration is not limited to this. That is, as with the first to third embodiments, it is not limited to this configuration as long as a predetermined resistance relationship holds before and after the electrothermal conversion elements 5 and 6 in the circulation flow path 7e. In this embodiment, as with the first to third embodiments, the first electrothermal conversion element 5 is positioned as the main energy generating element at the most effective position within the range of flow resistance ratio R1 / R2 of 0.05 to 0.4, and the second electrothermal conversion element 6 is positioned as a sub-element.

[0079] Regarding the drive signals, as in the first embodiment, the first electrothermal conversion element 5 and the second electrothermal conversion element 6 are driven alternately at different timings, as shown in Figure 5(c).

[0080] (effect) Similar to the first to third embodiments, by driving two electrothermal conversion elements in a dispersed manner, it is possible to increase the flow rate while suppressing localized heat generation compared to driving a single electrothermal conversion element at a high frequency.

[0081] Furthermore, regarding the three-dimensional flow path configuration in the third embodiment, if the supply and discharge flow paths are separated to avoid recirculation concentration, the through-flow path needs to be made longer, which increases flow resistance and raises concerns about a decrease in circulation efficiency. In contrast, in the configuration of this embodiment, the supply and discharge flow paths are located on the same line, resulting in a straight flow path configuration. Therefore, even if the flow rate is increased by arranging multiple electrothermal conversion elements, the effects of recirculation concentration are suppressed.

[0082] Furthermore, because the electrothermal conversion element and the discharge port are arranged on the same line, it is possible to arrange the discharge ports at high density regardless of the arrangement of the electrothermal conversion element.

[0083] (Fifth embodiment) Referring to Figure 9, only the differences between the recording element substrate 4f in the fifth embodiment of the present invention and the recording element substrates of the first to fourth embodiments will be described. In the fifth embodiment, matters not specifically described here are the same as in the above embodiments.

[0084] Figure 9 shows a part of the flow path near the discharge port in this embodiment. In the fourth embodiment, one first electrothermal conversion element 5 and one second electrothermal conversion element 6 are arranged for each discharge port 2. In contrast, in this embodiment, as shown in Figure 9, one first electrothermal conversion element 5 and one second electrothermal conversion element 6 are arranged for each of the multiple discharge ports 2.

[0085] The circulation channel 7f has an upstream channel 71f where the electrothermal conversion elements 5 and 6 are located, and a downstream channel 72f where the ink ejection unit 40 is located. The number of upstream channels 71f, which are provided in multiple locations corresponding to the multiple ink ejection units 40, arranged in the Y direction is less than the number of downstream channels 72f, which are provided in multiple locations corresponding to the multiple ink ejection units 40, arranged in the Y direction. Several of the multiple downstream channels 72f that are adjacent to each other in the Y direction are in communication with a common inlet 8 via a common upstream channel 71f. In other words, ink flowing in from one inlet 8 passes through one upstream channel 71f, then branches off into several downstream channels 72f that are adjacent to each other in the Y direction, and is discharged from several outlets 9 further down. That is, one of the multiple upstream channels 71f becomes a common channel that communicates with each of the several downstream channels 72f that are adjacent to each other in the Y direction among the multiple downstream channels 72f provided corresponding to the multiple ink ejection units 40. Furthermore, since the number of upstream flow channels 71f is less than the number of downstream flow channels 72f, the number of electrothermal conversion elements 5 and 6 aligned in the Y direction is less than the number of ink ejection sections 40 aligned in the Y direction.

[0086] In this embodiment, the first electric heat conversion element 5 is placed on the side closer to the discharge port 2, and the second electric heat conversion element 6 is placed on the side further away from the discharge port 2, with the two elements adjacent to each other. However, for example, the second electric heat conversion element 6 may be placed on the side closer to the discharge port 2, or multiple electric heat conversion elements may be arranged in a row. Also, in the configuration shown in Figure 9, one electric heat conversion element 5 and 6 are placed for every two discharge ports, but it is also possible to have a configuration where one electric heat conversion element 5 and 6 are placed for every three or more discharge ports.

[0087] (effect) In the configuration of this embodiment described above, since one first electrothermal conversion element 5 and one second electrothermal conversion element 6 are arranged for multiple discharge ports 2, the resolution of the electrothermal conversion elements 5 and 6 is lower than that of the discharge ports 2. As a result, the size of the electrothermal conversion elements 5 and 6 can be increased, making it possible to improve energy efficiency and circulate the energy.

[0088] Furthermore, in this embodiment, when the energy generating element for forming the circulating flow is an electrothermal conversion element, as the ink concentrates in the liquid delivery channel, the vapor bubbles generated on the electrothermal conversion element become smaller due to the increased viscosity of the ink, which leads to a decrease in circulation efficiency. In contrast, with the configuration of this embodiment, since the liquid delivery channel is arranged for each of the multiple discharge ports, the width of the liquid delivery channel can be increased, which reduces resistance in the liquid delivery channel and prevents a decrease in circulation efficiency.

[0089] Furthermore, according to this embodiment, similar to the first to fourth embodiments described above, two electrothermal conversion elements By driving the elements in a dispersed manner, it becomes possible to increase the flow rate while suppressing localized heat generation, compared to driving a single electrothermal conversion element at a high frequency.

[0090] (Sixth Embodiment) Referring to Figure 10, only the differences between the drive signal for the electrothermal conversion element in the recording element substrate of the sixth embodiment of the present invention and those of the first to fifth embodiments will be described. In the sixth embodiment, matters not specifically described here are the same as in the above embodiments.

[0091] Figure 10 shows the driving timing of the voltage pulses applied to the electrothermal conversion elements in this embodiment. Here, it is assumed that the first electrothermal conversion element 5 and the second electrothermal conversion element 6 are adjacent to each other (the electrothermal conversion elements are in a pair configuration). First, as in the first to fifth embodiments, the first electrothermal conversion element 5 is placed in the optimal position where the flow rate is greatest, and only the first electrothermal conversion element 5 is driven several times at a high frequency of 50 kHz. After that, the driving frequencies of the first electrothermal conversion element 5 and the second electrothermal conversion element 6 are driven at f1x=f2x=10 kHz, respectively. At this time, before the local temperature of the first electrothermal conversion element 5, which is driven at a high frequency, rises to the point where it affects foaming, the driving is switched to alternating between the first and second electrothermal conversion elements 5 and 6.

[0092] In other words, the drive control in this embodiment includes a first drive period in which only the first electrothermal conversion element 5 is repeatedly driven multiple times, and a second drive period in which the first electrothermal conversion element 5 and the second electrothermal conversion element 6 are repeatedly driven alternately. Furthermore, the drive frequency of the first electrothermal conversion element 5 is changed during the multiple times it is repeatedly driven from the first drive period to the second drive period. Specifically, the first electrothermal conversion element 5 is driven at a relatively high frequency (first frequency) during the first drive period, and at a relatively low frequency (second frequency) during the subsequent second drive period.

[0093] This allows the thickened ink to flow through the circulation channel at an increased flow rate, and after a certain amount of thickened ink has flowed, the first electrothermal conversion element 5 and the second electrothermal conversion element 6 are driven at reduced driving frequencies. This suppresses localized temperature increases while improving the effectiveness of circulating the thickened ink around the discharge port.

[0094] Furthermore, as mentioned above, when the energy generating element for forming the circulating flow is an electrothermal conversion element, there is a concern that the circulation efficiency will decrease due to the miniaturization of vapor bubbles generated on the electrothermal conversion element as the ink in the circulating channel becomes concentrated. In contrast, in this embodiment, by initially driving at a high frequency, the thickened ink on the electrothermal conversion element can be replaced with fresh ink in a short time, thus suppressing the decrease in efficiency of the electrothermal conversion element.

[0095] In addition, in a configuration like the second embodiment, which further includes a third electric heat conversion element 10 in addition to the first electric heat conversion element 5 and the second electric heat conversion element 6, the control may be as follows. That is, a first driving period in which only the first electric heat conversion element 5 is repeatedly driven multiple times, and a second driving period in which the first electric heat conversion element 5, the second electric heat conversion element 6, and the third electric heat conversion element 10 are repeatedly driven in this order may be provided. Furthermore, with respect to the first electric heat conversion element 5, the driving frequency of the first electric heat conversion element 5 may be changed during the multiple repeated driving from the first driving period to the second driving period. Specifically, the first electric heat conversion element 5 may be driven at a relatively high frequency (first frequency) during the first driving period, and at a relatively low frequency (second frequency) during the subsequent second driving period.

[0096] Each of the above embodiments can be combined with the others.

[0097] The disclosure of embodiments of the present invention includes the following configurations. (Composition 1) A liquid discharge unit having a pressure chamber, a discharge port for discharging liquid from the pressure chamber, and an energy generating element that generates energy to discharge the liquid in the pressure chamber from the discharge port, A circulation channel having an inlet through which liquid supplied to the pressure chamber flows in, and an outlet through which liquid recovered from the pressure chamber flows out, wherein the pressure chamber is positioned between the inlet and the outlet, In a liquid dispensing head equipped with, A first electrothermal conversion element is provided in the circulation channel on a side closer to the inlet than the energy generating element, In the circulation channel, a second electrothermal conversion element is provided on a side closer to the inlet than the energy generating element and adjacent to the first electrothermal conversion element, Equipped with, A liquid dispensing head characterized in that the first electrothermal conversion element and the second electrothermal conversion element are driven at different timings. (Configuration 2) The circulation channel further comprises a third electrothermal conversion element provided adjacent to the first electrothermal conversion element on the side closer to the inlet than the energy generating element and on the opposite side from the second electrothermal conversion element, The liquid discharge head according to Configuration 1, characterized in that the first electrothermal conversion element, the second electrothermal conversion element, and the third electrothermal conversion element are driven at different timings from each other. (Configuration 3) The liquid discharge head according to configuration 1 or 2, characterized in that the electrothermal conversion element is an energy generating element that generates energy to cause the liquid in the circulation channel to flow. (Composition 4) In the circulation channel, the first current resistance R1 between the inlet and the electrothermal conversion element and the second current resistance R2 between the inlet and the electrothermal conversion element are different. A liquid dispensing head according to any one of configurations 1 to 3, characterized by the features described above. (Composition 5) The discharge port opens in the first direction, The inlet and outlet are both located on one side of the liquid discharge section in a second direction intersecting the first direction, and are aligned in a third direction intersecting both the first and second directions. The aforementioned circulation channel is An upstream channel extending from the inlet toward the other side in the second direction, A downstream channel that changes direction in the opposite direction from the upstream channel and extends from the other side in the second direction toward the one side, Includes, The aforementioned electric heat conversion element is arranged in the upstream flow path, The liquid discharge unit is located in the downstream flow path. A liquid dispensing head according to any one of configurations 1 to 4, characterized by the features described above. (Composition 6) The system further includes a common flow path communicating with the inlet and outlet, respectively. Multiple liquid dispensing units are provided so as to be aligned in the third direction. The upstream flow path extends in the second direction between the multiple liquid discharge sections so as to intersect with the rows of the multiple liquid discharge sections. The common flow path is provided on one side of the inlet and outlet in the second direction, extending in the third direction, and is in communication with each of the multiple inlets and multiple outlets provided corresponding to the multiple liquid discharge sections. A liquid dispensing head according to configuration 5, characterized by the features described herein. (Composition 7) The multiple energy generating elements provided corresponding to the multiple liquid discharge sections and the multiple first electrothermal conversion elements provided corresponding to the multiple liquid discharge sections are arranged to be alternately aligned in the third direction. A liquid dispensing head according to configuration 5 or 6, characterized by the above. (Composition 8) On the first side, there is a substrate on which the liquid discharge section, the circulation channel, and the electrothermal conversion element are arranged, A channel forming member laminated on the first surface of the substrate, the channel forming member including a partition wall that forms a part of the circulation channel, An orifice plate is provided with the discharge port and is laminated on the side opposite to the substrate relative to the flow path forming member, Furthermore, The pressure chamber and the circulation channel are defined by the first surface of the substrate, the partition wall, and the orifice plate. A liquid dispensing head according to any one of configurations 5 to 7, characterized by the features described herein. (Composition 9) The first electrothermal conversion element and the second electrothermal conversion element are arranged adjacent to each other in the second direction at a position different from the energy generating element in the third direction. The aforementioned partition wall is A first partition wall extending in the second direction divides the space between the multiple circulation channels corresponding to the multiple liquid discharge sections in the third direction, In each of the aforementioned circulation channels, a second partition wall extending in the second direction divides the space between the energy generating element and the first electrothermal conversion element and the second electrothermal conversion element in the third direction, Includes, One side surface of the second partition wall in the third direction forms part of the upstream flow path. The other side of the second partition wall in the third direction forms part of the downstream flow path and the pressure chamber. A liquid dispensing head according to configuration 8, characterized by the above. (Composition 10) The substrate has a through hole that penetrates in the first direction between the first surface of the substrate and the second surface which is the back surface of the first surface, on one side of the inlet and outlet in the second direction. The common channel is defined by the through hole, the channel forming member, and the orifice plate. A liquid dispensing head according to configuration 8 or 9, characterized by the above. (Composition 11) The discharge port opens in the first direction, The inlet and outlet are aligned in the first direction and are both located on one side of the liquid discharge section in a second direction intersecting the first direction. The aforementioned circulation channel is An upstream channel extending from the inlet toward the other side in the second direction, A downstream channel that changes direction in the opposite direction from the upstream channel and extends from the other side in the second direction toward the one side, Includes, The aforementioned electric heat conversion element is arranged in the upstream flow path, The liquid discharge unit is located in the downstream flow path. A liquid dispensing head according to any one of the configurations 1 to 10, characterized in that it is a liquid dispensing head. (Composition 12) The liquid discharge unit and the electrothermal conversion element are provided at different positions in the first direction. A liquid dispensing head according to configuration 11, characterized by the features described above. (Composition 13) The system further includes a common flow path communicating with the inlet and outlet, respectively. Multiple liquid discharge units are provided so as to be aligned in a third direction that intersects both the first and second directions. The upstream channel and the downstream channel each extend in the second direction and are arranged to be aligned in the first direction. The common flow path is provided so as to extend in the third direction on one side of the inlet and outlet in the second direction, and communicates with each of the multiple inlets and multiple outlets provided corresponding to the multiple liquid discharge sections. A liquid dispensing head according to configuration 11 or 12, characterized by the above. (Composition 14) The multiple circulation channels provided corresponding to the multiple liquid discharge sections are arranged to be aligned in the third direction. The multiple energy generating elements provided in relation to the multiple liquid discharge sections are arranged to be aligned in the third direction. The multiple first electrothermal conversion elements, which are provided in accordance with the multiple liquid discharge sections, are arranged to be aligned in the third direction. The multiple second electrothermal conversion elements, which are provided corresponding to the multiple liquid discharge sections, are arranged to be aligned in the third direction. A liquid dispensing head according to any one of the configurations 11 to 13, characterized by the features described above. (Composition 15) A first substrate having a first surface on which the liquid discharge portion is arranged and which forms part of the downstream flow path and the pressure chamber; a second surface which is the back surface of the first surface and forms part of the upstream flow path; and a connecting hole which penetrates between the first surface and the second surface in the first direction and forms a connecting flow path that connects the upstream flow path and the downstream flow path in the circulation flow path, A first channel forming member is laminated on the first surface of the first substrate and forms part of the downstream channel and the pressure chamber, An orifice plate is provided with the discharge port, is laminated on the side opposite to the first substrate with respect to the first flow path forming member, and forms part of the downstream flow path and the pressure chamber, A second channel forming member is laminated on the second surface of the first substrate and forms a part of the upstream channel, A second substrate is laminated on the side opposite to the first substrate with respect to the second channel forming member, and the first electrothermal conversion element and the second electrothermal conversion element are arranged on the side facing the second channel forming member, forming a part of the upstream channel, On one side of the inlet and outlet in the second direction, a common hole is provided that sequentially penetrates the first channel forming member, the first substrate, the second channel forming member, and the second substrate in the first direction, forming the common channel. A liquid dispensing head according to any one of the configurations 11 to 14, characterized by the features described above. (Composition 16) The discharge port opens in the first direction, The inlet is located on one side in a second direction intersecting the first direction with respect to the pressure chamber. The outlet is located on the other side in the second direction relative to the pressure chamber. The circulation channel extends in the second direction such that the inlet, the pressure chamber, and the outlet are arranged in this order in the second direction. The aforementioned electrothermal conversion element is located in the circulation channel, and is more efficient than the energy generating element at the inlet. It is positioned on the side closer to the user. A liquid dispensing head according to any one of configurations 1 to 15, characterized by the features described herein. (Composition 17) The system further includes a common flow path communicating with the inlet and outlet, respectively. Multiple liquid discharge units are provided so as to be aligned in a third direction that intersects both the first and second directions. The common flow path communicates with each of the multiple inlets and multiple outlets provided corresponding to the multiple liquid discharge sections. A liquid dispensing head according to configuration 16, characterized by the features described above. (Composition 18) The multiple circulation channels provided corresponding to the multiple liquid discharge sections are arranged to be aligned in the third direction. The multiple energy generating elements provided in relation to the multiple liquid discharge sections are arranged to be aligned in the third direction. The multiple first electrothermal conversion elements, which are provided in accordance with the multiple liquid discharge sections, are arranged to be aligned in the third direction. The multiple second electrothermal conversion elements, which are provided corresponding to the multiple liquid discharge sections, are arranged to be aligned in the third direction. A liquid dispensing head according to configuration 16 or 17, characterized by the above. (Composition 19) The first side further comprises a substrate on which the liquid discharge section, the circulation channel, and the electrothermal conversion element are arranged. The aforementioned substrate is On one side of the inlet in the second direction, a supply-side through-flow channel is provided that penetrates in the first direction between the first surface of the substrate and the second surface which is the back surface of the first surface, On the other side of the outlet in the second direction, between the first surface and the second surface of the substrate, there is an outlet-side through-flow channel that penetrates in the first direction, It has, The common channel is formed on the second surface side of the substrate so as to communicate with the supply-side through-channel and the discharge-side through-channel, respectively. A liquid dispensing head according to any one of the configurations 16 to 18, characterized by the features described above. (Composition 20) The supply-side through-flow channel communicates with each of the multiple inlets provided corresponding to the multiple liquid discharge sections, The discharge-side through-flow channel communicates with each of the multiple outlets provided corresponding to the multiple liquid discharge sections. A liquid dispensing head according to configuration 19, characterized by the features described above. (Composition 21) A channel forming member laminated on the first surface of the substrate, comprising a plurality of partition walls extending in the second direction between a plurality of energy generating elements aligned in the third direction corresponding to the plurality of liquid discharge portions, An orifice plate is provided with the discharge port and is laminated on the side opposite to the substrate relative to the flow path forming member, Furthermore, The pressure chamber and the circulation channel are defined by the first surface of the substrate, the partition wall, and the orifice plate. A liquid dispensing head according to any one of the configurations 16 to 20, characterized by the features described above. (Composition 22) The channel forming member is designated as the first channel forming member. A second channel forming member laminated on the second surface of the substrate, further comprising a second channel forming member that defines the common channel together with the second surface, The common flow path communicates with each of the plurality of circulation flow paths via the supply-side through-flow path and the discharge-side through-flow path. A liquid dispensing head according to configuration 21, characterized by the features described above. (Composition 23) The channel forming member is designated as the first channel forming member. A second channel forming member laminated on the second surface of the substrate, further comprising a second channel forming member that defines the common channel together with the second surface, The aforementioned common channel is A common supply channel communicates with each of the plurality of circulation channels via the aforementioned supply-side through-channel, A common discharge channel communicates with each of the plurality of circulation channels via the aforementioned discharge-side through-channel, including, A liquid dispensing head according to configuration 21 or 22, characterized by the above. (Composition 24) The aforementioned circulation channel is The upstream channel where the electrothermal conversion element is arranged, The downstream flow path where the liquid discharge section is located, Includes, The multiple upstream passages provided in accordance with the multiple liquid discharge sections are arranged such that one of the upstream passages becomes a common passage that communicates with each of the multiple downstream passages provided in accordance with the multiple liquid discharge sections, which are adjacent to each other in the third direction. The number of the multiple upstream flow paths aligned in the third direction is less than the number of the multiple liquid discharge sections aligned in the third direction. The number of electrothermal conversion elements arranged in the third direction, corresponding to the multiple liquid discharge sections, is less than the number of liquid discharge sections arranged in the third direction. A liquid dispensing head according to any one of the configurations 16 to 23, characterized by the features described above. (Composition 25) The first electrothermal conversion element and the second electrothermal conversion element are driven alternately and repeatedly. A liquid dispensing head according to any one of the configurations 1 to 24, characterized by the features described above. (Composition 26) The first electrothermal conversion element, the second electrothermal conversion element, and the third electrothermal conversion element are repeatedly driven in this order. A liquid dispensing head according to configuration 2, characterized by the features described above. (Composition 27) The first electrothermal conversion element and the second electrothermal conversion element are, A first driving period in which only the first electrothermal conversion element is driven repeatedly multiple times, A second driving period in which the first electrothermal conversion element and the second electrothermal conversion element are repeatedly driven alternately, A liquid dispensing head according to any one of configurations 1 to 26, characterized by having the following: (Configuration 28) The first electrothermal conversion element, the second electrothermal conversion element, and the third electrothermal conversion element are, A first driving period in which only the first electrothermal conversion element is driven repeatedly multiple times, A second driving period in which the first electrothermal conversion element, the second electrothermal conversion element, and the third electrothermal conversion element are repeatedly driven in this order, A liquid dispensing head according to configuration 2, characterized by having the following features. (Composition 29) The driving frequency of the first electrothermal conversion element changes during multiple repeated driving cycles. A liquid dispensing head according to any one of the configurations 1 to 28, characterized by the features described above. (Composition 30) The current resistance ratio R1 / R2 of the first current resistance R1 and the second current resistance R2 is between 0.05 and 0.4. A liquid dispensing head according to configuration 4, characterized by the features described above. (Composition 31) A liquid dispensing head described in any one of configurations 1 to 30, A control unit that controls the driving of the aforementioned electric heat conversion element, A liquid dispensing device characterized by comprising the following features. [Explanation of symbols]

[0098] 1...Energy generating element, 2...Discharge port, 3...Pressure chamber, 40...Ink ejection section, 4...Recording element substrate, 5...First electrothermal conversion element, 6...Second electrothermal conversion element, 7...Circulation channel, 8...Supply channel, 9...Discharge channel, 11...Through-through channel, 12...Common channel, 13...First channel member, 14...Filter, 15...Second channel member, 16...Orifice plate, 17...First substrate, 18...Second substrate, 19...Third substrate, 21...Supply-through channel on the supply side, 22...Through-through channel on the discharge side, 24...Common channel on the supply side, 25...Common channel on the discharge side, 100...Recording head

Claims

1. A liquid discharge unit having a pressure chamber, a discharge port for discharging liquid from the pressure chamber, and an energy generating element that generates energy to discharge the liquid in the pressure chamber from the discharge port, A circulation channel having an inlet through which liquid supplied to the pressure chamber flows in, and an outlet through which liquid recovered from the pressure chamber flows out, wherein the pressure chamber is positioned between the inlet and the outlet, In a liquid dispensing head equipped with, A first electrothermal conversion element is provided in the circulation channel on a side closer to the inlet than the energy generating element, In the circulation channel, a second electrothermal conversion element is provided on a side closer to the inlet than the energy generating element and adjacent to the first electrothermal conversion element, Equipped with, A liquid dispensing head characterized in that the first electrothermal conversion element and the second electrothermal conversion element are driven at different timings.

2. The circulation channel further comprises a third electrothermal conversion element provided adjacent to the first electrothermal conversion element on the side closer to the inlet than the energy generating element and on the side opposite to the second electrothermal conversion element, The liquid discharge head according to claim 1, characterized in that the first electrothermal conversion element, the second electrothermal conversion element, and the third electrothermal conversion element are driven at different timings from each other.

3. The liquid discharge head according to claim 1, characterized in that the electric heat conversion element is an energy generating element that generates energy to cause the liquid in the circulation channel to flow.

4. In the aforementioned circulation channel, the first current resistance R1 between the inlet and the electrothermal conversion element and the second current resistance R2 between the inlet and the electrothermal conversion element are different. The liquid dispensing head according to feature 1.

5. The discharge port opens in the first direction, The inlet and outlet are both located on one side of the liquid discharge section in a second direction intersecting the first direction, and are aligned in a third direction intersecting both the first and second directions. The aforementioned circulation channel is An upstream channel extending from the inlet toward the other side in the second direction, A downstream channel that changes direction in the opposite direction from the upstream channel and extends from the other side in the second direction toward the one side, Includes, The aforementioned electric heat conversion element is arranged in the upstream flow path, The liquid discharge unit is located in the downstream flow path. The liquid dispensing head according to feature 1.

6. The system further includes a common flow path communicating with the inlet and outlet, respectively. Multiple liquid dispensing units are provided so as to be aligned in the third direction. The upstream flow path extends in the second direction between the multiple liquid discharge sections so as to intersect with the rows of the multiple liquid discharge sections. The common flow path is provided so as to extend in the third direction on one side of the inlet and outlet in the second direction, and is provided corresponding to the plurality of liquid discharge sections. Communicating with each of the multiple inlets and multiple outlets The liquid dispensing head according to feature 5.

7. The multiple energy generating elements provided corresponding to the multiple liquid discharge sections and the multiple first electrothermal conversion elements provided corresponding to the multiple liquid discharge sections are arranged to be alternately aligned in the third direction. The liquid dispensing head according to feature 6.

8. On the first side, there is a substrate on which the liquid discharge section, the circulation channel, and the electrothermal conversion element are arranged, A channel forming member laminated on the first surface of the substrate, the channel forming member including a partition wall that forms a part of the circulation channel, An orifice plate is provided with the discharge port and is laminated on the side opposite to the substrate relative to the flow path forming member, Furthermore, The pressure chamber and the circulation channel are defined by the first surface of the substrate, the partition wall, and the orifice plate. The liquid dispensing head according to feature 6.

9. The first electrothermal conversion element and the second electrothermal conversion element are arranged adjacent to each other in the second direction at a position different from the energy generating element in the third direction. The aforementioned partition wall is A first partition wall extending in the second direction divides the space between the multiple circulation channels corresponding to the multiple liquid discharge sections in the third direction, In each of the aforementioned circulation channels, a second partition wall extending in the second direction divides the space between the energy generating element and the first electrothermal conversion element and the second electrothermal conversion element in the third direction, Includes, One side surface of the second partition wall in the third direction forms part of the upstream flow path, The other side of the second partition wall in the third direction forms part of the downstream flow path and the pressure chamber. The liquid dispensing head according to feature 8.

10. The substrate has a through hole that penetrates in the first direction between the first surface of the substrate and the second surface which is the back surface of the first surface, on one side of the inlet and outlet in the second direction. The common channel is defined by the through hole, the channel forming member, and the orifice plate. The liquid dispensing head according to feature 8.

11. The discharge port opens in the first direction, The inlet and outlet are aligned in the first direction and are both located on one side of the liquid discharge section in a second direction intersecting the first direction. The aforementioned circulation channel is An upstream channel extending from the inlet toward the other side in the second direction, A downstream channel that changes direction in the opposite direction from the upstream channel and extends from the other side in the second direction toward the one side, Includes, The aforementioned electric heat conversion element is arranged in the upstream flow path, The liquid discharge unit is located in the downstream flow path. The liquid dispensing head according to feature 1.

12. The liquid discharge unit and the electrothermal conversion element are provided at different positions in the first direction. The liquid dispensing head according to feature 11.

13. The system further includes a common flow path communicating with the inlet and outlet, respectively. Multiple liquid discharge units are provided so as to be aligned in a third direction that intersects both the first and second directions. The upstream channel and the downstream channel each extend in the second direction and are arranged to be aligned in the first direction. The common flow path is provided so as to extend in the third direction on one side of the inlet and outlet in the second direction, and communicates with each of the multiple inlets and multiple outlets provided corresponding to the multiple liquid discharge sections. The liquid dispensing head according to feature 12.

14. The multiple circulation channels provided corresponding to the multiple liquid discharge sections are arranged to be aligned in the third direction. The multiple energy generating elements provided in relation to the multiple liquid discharge sections are arranged to be aligned in the third direction. The multiple first electrothermal conversion elements, which are provided corresponding to the multiple liquid discharge sections, are arranged to be aligned in the third direction. The multiple second electrothermal conversion elements, which are provided corresponding to the multiple liquid discharge sections, are arranged to be aligned in the third direction. The liquid dispensing head according to feature 13.

15. A first substrate having a first surface on which the liquid discharge section is arranged and which forms part of the downstream flow path and the pressure chamber; a second surface which is the back surface of the first surface and forms part of the upstream flow path; and a connecting hole which penetrates between the first surface and the second surface in the first direction and forms a connecting flow path that connects the upstream flow path and the downstream flow path in the circulation flow path, A first channel forming member is laminated on the first surface of the first substrate and forms part of the downstream channel and the pressure chamber, An orifice plate is provided with the discharge port, is laminated on the side opposite to the first substrate with respect to the first flow path forming member, and forms part of the downstream flow path and the pressure chamber, A second channel forming member is laminated on the second surface of the first substrate and forms a part of the upstream channel, The second substrate is laminated on the side opposite to the first substrate with respect to the second channel forming member, and the first electrothermal conversion element and the second electrothermal conversion element are arranged on the side facing the second channel forming member, forming a part of the upstream channel, On one side of the inlet and outlet in the second direction, a common hole is provided that sequentially penetrates the first flow path forming member, the first substrate, the second flow path forming member, and the second substrate in the first direction, forming the common flow path. The liquid dispensing head according to feature 13.

16. The discharge port opens in the first direction, The inlet is located on one side in a second direction intersecting the first direction with respect to the pressure chamber. The outlet is located on the other side in the second direction relative to the pressure chamber. The circulation channel extends in the second direction such that the inlet, the pressure chamber, and the outlet are arranged in this order in the second direction. The electrothermal conversion element is positioned in the circulation channel closer to the inlet than the energy generating element. The liquid dispensing head according to feature 1.

17. The system further includes a common flow path communicating with the inlet and outlet, respectively. Multiple liquid discharge units are provided so as to be aligned in a third direction that intersects both the first and second directions. The common flow path communicates with each of the multiple inlets and multiple outlets provided corresponding to the multiple liquid discharge sections. The liquid dispensing head according to feature 16.

18. The multiple circulation channels provided corresponding to the multiple liquid discharge sections are arranged to be aligned in the third direction. The multiple energy generating elements provided in relation to the multiple liquid discharge sections are arranged to be aligned in the third direction. The multiple first electrothermal conversion elements, which are provided corresponding to the multiple liquid discharge sections, are arranged to be aligned in the third direction. The multiple second electrothermal conversion elements, which are provided corresponding to the multiple liquid discharge sections, are arranged to be aligned in the third direction. The liquid dispensing head according to feature 17.

19. The first side further comprises a substrate on which the liquid discharge section, the circulation channel, and the electrothermal conversion element are arranged. The aforementioned substrate is On one side of the inlet in the second direction, a supply-side through-flow channel is provided that penetrates in the first direction between the first surface of the substrate and the second surface which is the back surface of the first surface, On the other side of the outlet in the second direction, a discharge-side through-flow channel is provided that penetrates the first direction between the first surface and the second surface of the substrate, It has, The common channel is formed on the second surface side of the substrate so as to communicate with the supply-side through-channel and the discharge-side through-channel, respectively. The liquid dispensing head according to feature 17.

20. The supply-side through-flow channel communicates with each of the multiple inlets provided corresponding to the multiple liquid discharge sections, The discharge-side through-flow channel communicates with each of the multiple outlets provided corresponding to the multiple liquid discharge sections. The liquid dispensing head according to feature 19.

21. A channel forming member laminated on the first surface of the substrate, comprising a plurality of partition walls extending in the second direction between a plurality of energy generating elements aligned in the third direction corresponding to the plurality of liquid discharge portions, An orifice plate is provided with the discharge port and is laminated on the side opposite to the substrate relative to the flow path forming member, Furthermore, The pressure chamber and the circulation channel are defined by the first surface of the substrate, the partition wall, and the orifice plate. The liquid dispensing head according to feature 19.

22. The channel forming member is designated as the first channel forming member. A second channel forming member laminated on the second surface of the substrate, further comprising a second channel forming member that defines the common channel together with the second surface, The common flow path communicates with each of the plurality of circulation flow paths via the supply-side through-flow path and the discharge-side through-flow path. The liquid dispensing head according to feature 21.

23. The channel forming member is designated as the first channel forming member. A second channel forming member laminated on the second surface of the substrate, further comprising a second channel forming member that defines the common channel together with the second surface, The aforementioned common channel is A common supply channel communicates with each of the plurality of circulation channels via the aforementioned supply-side through-channel, A common discharge channel communicates with each of the plurality of circulation channels via the aforementioned discharge-side through-channel, including, The liquid dispensing head according to feature 21.

24. The aforementioned circulation channel is The upstream channel where the electrothermal conversion element is arranged, The downstream flow path where the liquid discharge section is located, Includes, The multiple upstream flow paths provided in correspondence with the multiple liquid discharge sections are arranged such that one of the upstream flow paths becomes a common flow path communicating with each of the multiple downstream flow paths provided in correspondence with the multiple liquid discharge sections, each of which is adjacent to each other in the third direction. The number of the multiple upstream flow paths aligned in the third direction is less than the number of the multiple liquid discharge sections aligned in the third direction. The number of electrothermal conversion elements arranged in the third direction, corresponding to the multiple liquid discharge sections, is less than the number of liquid discharge sections arranged in the third direction. The liquid dispensing head according to feature 17.

25. The first electrothermal conversion element and the second electrothermal conversion element are driven alternately and repeatedly. The liquid dispensing head according to feature 1.

26. The first electrothermal conversion element, the second electrothermal conversion element, and the third electrothermal conversion element are repeatedly driven in this order. The liquid dispensing head according to feature 2.

27. The first electrothermal conversion element and the second electrothermal conversion element are, A first driving period in which only the first electrothermal conversion element is driven repeatedly multiple times, A second driving period in which the first electrothermal conversion element and the second electrothermal conversion element are repeatedly driven alternately, A liquid dispensing head according to claim 1, characterized by having the following features.

28. The first electrothermal conversion element, the second electrothermal conversion element, and the third electrothermal conversion element are, A first driving period in which only the first electrothermal conversion element is driven repeatedly multiple times, The first electrothermal conversion element, the second electrothermal conversion element, and the third electrothermal conversion element are This sequence is repeated for the second drive period, The liquid dispensing head according to claim 2, characterized by having the following features.

29. The driving frequency of the first electrothermal conversion element changes during repeated operation. The liquid dispensing head according to claim 27 or 28.

30. The flow resistance ratio R1 / R2 of the first flow resistance R1 and the second flow resistance R2 is between 0.05 and 0.

4. The liquid dispensing head according to feature 4.

31. The liquid dispensing head according to claim 1, A control unit that controls the driving of the aforementioned electric heat conversion element, A liquid dispensing device characterized by comprising the following features.

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