Liquid ejection head

Abstract

To provide a liquid discharge head which can detect a temperature of a liquid with high sensitivity.SOLUTION: A liquid discharge head 118 includes: a base 100; a discharge port 111; a heating element 102; a temperature detection element 115 which detects a temperature of a liquid; a wiring layer electrically connected to the heating element 102; a protection layer 101 which protects the heating element 102 and the wiring layer from the liquid; and a liquid supply port 108 for supplying the liquid to the discharge port 111. When viewed from a direction perpendicular to the base 100, the temperature detection element 115 is disposed between the heating element 102 and the liquid supply port 108 and formed on the protection layer 101.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a liquid ejection head that ejects liquid. [Background technology]

[0002] A liquid ejection printer is an example of a recording device that ejects liquid to perform recording. A liquid ejection printer is equipped with a liquid ejection head, which is a component that ejects liquid. Some liquid ejection heads are designed to cause film boiling of the liquid in order to generate pressure for ejecting the liquid from the ejection orifices. To cause film boiling of the liquid, the liquid ejection head has a heating element.

[0003] A liquid ejection head is known that is equipped with a temperature detection element (temperature sensor) that can detect the temperature of the liquid in order to detect whether or not the liquid is being ejected normally from the ejection port when a heating element is used (hereinafter referred to as ejection detection). Patent Document 1 discloses a method of ejection detection that uses a temperature detection element called a flow sensor. Discharge detection is performed by utilizing the fact that the temperature of the liquid detected by the flow sensor differs between a state in which the liquid is being ejected normally from the ejection port and a state in which ejection is faulty. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-83227 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in Patent Document 1, a protective layer or the like is formed on the flow sensor, and the flow sensor detects the temperature of the liquid through the protective layer or the like, which causes a problem of low sensitivity in detecting the temperature of the liquid.

[0006] SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide a liquid ejection head that can detect the temperature of the liquid with high sensitivity. [Means for solving the problem]

[0007] In order to solve the above problems, the present invention provides a liquid ejection head comprising: an insulating layer disposed on a base; a heat generating resistor element disposed in the insulating layer and generating thermal energy for ejecting a liquid; a bubbling chamber disposed above the insulating layer and for bubbling the liquid based on the thermal energy; and a first temperature detecting element capable of detecting a temperature in the bubbling chamber; In the thickness direction of the substrate the first temperature detection element is before the first temperature detection element is disposed between the heating resistor element and the bubbling chamber and on one of a plurality of conductive layers provided on the insulating layer that is closest to the bubbling chamber, the first temperature detection element being disposed outside of a position directly above the heating resistor element in a plan view; ,before The first temperature detection element is disposed in the foaming chamber and is heated before detection by a means different from that of the heating resistor element. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a liquid ejection head that can detect the temperature of the liquid with high sensitivity. [Brief explanation of the drawings]

[0009] [Figure 1] 1A and 1B are a plan view and a cross-sectional view schematically showing a liquid ejection head. [Figure 2] 3A and 3B are diagrams illustrating the operating principle of a liquid ejection head. [Figure 3] 5A and 5B are diagrams showing the state of liquid in a bubble-forming chamber of the liquid ejection head. [Figure 4] 1A and 1B are a plan view and a cross-sectional view schematically showing a liquid ejection head. [Figure 5] 3A and 3B are diagrams illustrating the operating principle of a liquid ejection head. [Figure 6] 1A and 1B are a plan view and a cross-sectional view schematically showing a liquid ejection head. [Figure 7]3A and 3B are diagrams illustrating the operating principle of a liquid ejection head. [Figure 8] 5A and 5B are diagrams showing the state of liquid in a bubble-forming chamber of the liquid ejection head. [Figure 9] 1A and 1B are a plan view and a cross-sectional view schematically showing a liquid ejection head. [Figure 10] 1A and 1B are a plan view and a cross-sectional view schematically showing a liquid ejection head. [Figure 11] 5A and 5B are diagrams showing the state of liquid in a bubble-forming chamber of the liquid ejection head. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Identical or similar components are designated by common reference numerals, and descriptions of components designated by common reference numerals will be omitted as appropriate.

[0011] (First embodiment) The first embodiment will be described with reference to FIG. 1. FIG. 1(a) is a schematic plan view of a liquid ejection head. FIG. 1(b) is a schematic cross-sectional view of the liquid ejection head taken along line A-A' in FIG. 1(a). FIG. 1(c) is a schematic cross-sectional view of the liquid ejection head taken along line B-B' in FIG. 1(a). The liquid ejection head has a substrate 100 made of, for example, single-crystal silicon. An insulating layer 101 is disposed on the substrate 100. The insulating layer 101 is formed of an inorganic material, for example, silicon oxide, and has electrical insulation properties, electrically isolating each wiring. Although not shown, a wiring layer made of transistors and multilayer wiring is disposed on the substrate and on the substrate. The wiring layer is electrically connected to a heat-generating resistor element 102 (also referred to as a heating element) that heats the liquid in order to eject the liquid from the ejection orifice. The insulating layer 101 also functions to protect the wiring layer and other elements from the liquid, and is therefore also referred to as a protective layer.

[0012] A heating resistor element 102 is disposed in an insulating layer 101. The heating resistor element 102 is connected to a power supply wiring 104 through a via 103. The heating resistor element 102 is made of a resistance material such as tantalum silicon nitride or tungsten silicon nitride.

[0013] An anti-cavitation film 105 is disposed on an insulating layer 101 located on the heating element (on the heating resistance element 102). The anti-cavitation film 105 is a film for protecting the heating resistance element 102, the insulating layer 101, the wiring layer, etc. from cavitation generated when the heating resistance element 102 is driven. The anti-cavitation film 105 is connected to a signal wiring 107 through a via 106. However, the anti-cavitation film 105 may be floating, and is not necessarily connected to the via 106 or the signal wiring 107. The anti-cavitation film 105 is formed as a single layer or a multilayer of a metal material or alloy with high mechanical and chemical strength, such as iridium, tantalum, titanium, tungsten, silicon, tantalum silicon nitride, or tungsten silicon nitride.

[0014] On the anti-cavitation film 105, a filter 109 made of photosensitive resin or the like and a nozzle forming member 110 form an ejection port 111 and a bubbling chamber 112. Also formed is a liquid supply port 108 (sometimes simply referred to as a supply port) for the liquid that penetrates the base 100 and the insulating layer 101. The bubbling chamber 112 is an area that contributes to the ejection of the liquid, an area that is slightly larger than the heating resistor element 102 in plan view, and an area that is located at least closer to the ejection port 111 than the wall of the nozzle forming member 110 and the filter 109.

[0015] A temperature detection element 115 is disposed on the same layer as the anti-cavitation film 105. The anti-cavitation film 105 is formed on a protective layer. The temperature detection element 115 is also formed on a protective layer. Therefore, the temperature detection element 115 may be in direct contact with the liquid. When viewed perpendicularly to the substrate, the temperature detection element 115 is disposed between the heating resistor element 102 and the liquid supply port 108. The temperature detection element 115 is connected to a signal wiring 117 through a via 116. The temperature detection element 115 is formed as a single layer or a multilayer of a metal material or alloy with a large temperature coefficient of resistance, such as iridium, tantalum, titanium, tungsten, silicon, tantalum silicon nitride, or tungsten silicon nitride. The temperature detection element 115 may be made of the same material as the anti-cavitation film 105. Alternatively, the temperature detection element 115 may be formed simultaneously with the anti-cavitation film 105. If the manufacturing process for the temperature detection element 115 is also used for the anti-cavitation film 105, a process dedicated to the temperature detection element 115 becomes unnecessary, and it becomes possible to reduce manufacturing costs.

[0016] The power supply wiring 104 and the signal wiring 107, 117 are formed of a metal material primarily composed of, for example, aluminum or copper. The vias 103, 106, 117 are formed of a metal material primarily composed of, for example, tungsten or copper. The top surface of the insulating layer 101 is planarized. Planarization is performed, for example, by CMP (Chemical Mechanical Polishing). The planarization may be performed before or after each formation process of the vias, signal wiring, power supply wiring, heating resistor element, and temperature detection element. The heating resistor element 102 has a film thickness of 10 to 50 nm, and the power supply wiring 104 has a film thickness of 500 to 1000 nm. As such, the insulating layer 101 is provided with multiple conductive layers, including multilayer wiring (not shown), the heating resistor element 102, the vias 103, 106, 116, the power supply wiring 104, the signal wiring 107, 117, the anti-cavitation film 105, and the temperature detection element 115.

[0017] The liquid ejection head ejects liquid in the bubbling chamber 112 from the ejection port 111 using the thermal energy of the heating resistor element 102. After that, the liquid in the bubbling chamber 112 is replenished with the ejected tail liquid and the liquid supplied from the supply port 108. The temperature detection element 115 detects the change in temperature at that time and determines whether the liquid is being ejected normally. When the liquid is being ejected normally, the amount of refill liquid is large, so a lot of low-temperature liquid flows over the temperature detection element 115. On the other hand, when the liquid is not being ejected normally, the amount of refill is small (or zero), so there is little low-temperature liquid flowing over the temperature detection element 115. Due to this difference, the temperature detected by the temperature detection element 115 is low in the case of normal ejection, and high in the case of defective ejection. This temperature difference is used to detect ejection.

[0018] Specific examples of liquid ejection and detection methods using a temperature detection element will be described with additional reference to Figures 2 and 3. Figure 2 is a schematic diagram for explaining the operating principle of this embodiment. Figure 2(a) is a waveform diagram of a drive pulse applied to the heating resistor element 102. Figure 2(b) is a diagram showing changes in the liquid flow rate on the time axis when the direction from the supply port 108 to the ejection port 111 shown in Figure 1 is positive. Figure 2(c) is a waveform diagram of a current applied to the temperature detection element 115. Figure 2(d) is a diagram showing changes in the temperature of the liquid above the temperature detection element 115 on the time axis. Figure 2(e) is a waveform diagram of a detected output voltage corresponding to changes in liquid temperature.

[0019] 2(c), the current supplied to the temperature detection element 115 has a PA pulse that is at a high level from time t1 to t2 and a PB pulse that is at a high level from time t3 to t4. The PA pulse is a current applied to heat the temperature detection element 115. The PB pulse is a current that detects the resistance value of the temperature detection element 115.

[0020] Figure 3 is a schematic diagram for explaining the behavior of the liquid in the bubbling chamber during the ejection operation in this embodiment. To make it easier to understand their positional relationships, the heating resistor element 302, anti-cavitation film 305, temperature detection element 315, and bubbling chamber 312 are shown in schematic form. Figure 3(a) shows the behavior during normal ejection, and Figure 3(b) shows the behavior during a typical ejection failure.

[0021] The behavior during normal ejection will be explained with reference to Figure 3(a). Starting from a steady state (tA), when a drive pulse is applied to the heating resistor element 302, boiling occurs above the heating resistor element 302 in the liquid in the bubble-forming chamber, causing a bubble to grow (tB). When the pulse application ends, the bubble disappears. As the liquid disappears, the front part of the liquid separates, flying through the air as droplets and landing on a recording medium, for example. The remaining liquid, excluding the separated part, retreats into the bubble-forming chamber due to the negative pressure generated when the bubble disappears. This is called the tailing liquid or part of the ejected droplet, and falls to the solid surface (tC). When the liquid refills, the liquid interface moves toward the ejection port 111. This is caused by capillary forces within the bubble-forming chamber. As a result, as shown in Figure 2(b), when the bubble formation occurs, the liquid flows toward the supply port 108, then flows toward the ejection port 111 once the bubble volume reaches its maximum. When the liquid refill is complete, the steady state returns (tD).

[0022] The behavior during non-ejection will be explained with reference to Figure 3(b). When a drive pulse is applied to the heating resistor element 302, a boiling phenomenon occurs and bubbles grow, but the liquid does not separate. Because no liquid is ejected in this way, the amount of liquid reduced by the liquid ejection operation is zero. As a result, the amount of liquid refilled is smaller than in the case of normal ejection, and the time required for refilling is also longer.

[0023] The temperature of the liquid changes in the cases of normal and non-discharge as shown in Figure 2(d). A difference also occurs in the detected output voltage as shown in Figure 2(e). This difference in liquid temperature and output voltage can be used to determine whether or not discharge is occurring normally. Note that Figure 2(e) is an example in which a material with a positive resistance temperature coefficient is used as the temperature detection element; if a material with a negative resistance temperature coefficient is used as the temperature detection element, the trend will be reversed.

[0024] In this embodiment, the temperature detection element 115 is disposed in the same layer as the anti-cavitation film 105, and is disposed as a metal material closest to the liquid in the bubble-forming chamber 112. In other words, since the temperature detection element 115 is formed on the protective layer, the temperature detection element 115 may be in direct contact with the liquid. This allows the temperature detection element 115 to achieve high sensitivity. The high sensitivity of the temperature detection element 115 makes it possible to prevent false detections in discharge detection.

[0025] To increase the sensitivity of temperature detection, the temperature detection element 115 may be heated as needed before detecting the temperature. By pre-heating the temperature detection element 115, the temperature difference that occurs when refilling with liquid increases, allowing for more accurate temperature detection.

[0026] (Second embodiment) A second embodiment will be described with reference to Figure 4. Figure 4(a) is a schematic plan view of a liquid ejection head 118. Figure 4(b) is a schematic cross-sectional view of the liquid ejection head 118 taken along line CC' in Figure 4(a). Figure 4(c) is a schematic cross-sectional view of the liquid ejection head 118 taken along line DD' in Figure 4(a). In the second embodiment, an example of a configuration in which the temperature detection element is heated not by self-heating but by a second heating resistance element is described, thereby further increasing sensitivity.

[0027] In the second embodiment, a second heating resistor element 402 is disposed below the temperature detection element 115 via the insulating layer 101. The heating resistor element 402 is connected to a power supply wiring 404 via a via 403. The second heating resistor element 402 is formed of a resistance material such as tantalum silicon nitride or tungsten silicon nitride. The second heating resistor element 402 is made of the same material as the first heating resistor element 102 and is processed in the same process, so that it can be disposed without increasing manufacturing costs. The power supply wiring 404 is formed of a metal material mainly composed of, for example, aluminum or copper. The via 403 is formed of a metal material mainly composed of, for example, tungsten or copper.

[0028] With additional reference to FIG. 5, a specific example of a method for discharging liquid and detecting it using a temperature detection element will be described. FIG. 5 is a schematic diagram for explaining the operating principle of this embodiment. FIG. 5(a) is a waveform diagram of a drive pulse applied to the first heating resistor element 102. FIG. 5(b) is a diagram showing changes in the flow rate of liquid on the time axis when the direction from the supply port 108 to the discharge port 111 shown in FIG. 5 is defined as positive. FIG. 5(c) is a waveform diagram of a current applied to the second heating resistor element 402. FIG. 5(d) is a waveform diagram of a current applied to the temperature detection element 115. FIG. 5(e) is a waveform diagram of a detected output voltage corresponding to changes in liquid temperature.

[0029] The current applied to the second heating resistor element 402 in Figure 5(c) is a current applied to heat the temperature detection element 115 and the liquid around the temperature detection element 115. The current applied to the second heating resistor element 402 is controlled to a level that does not cause the liquid around the temperature detection element 115 to bubble. The current applied to the temperature detection element 115 in Figure 5(d) is a current that detects the resistance value of the temperature detection element 115. There is a difference in the detected output voltage between normal ejection and non-ejection, as shown in Figure 5(e). This makes it possible to determine whether the liquid is being ejected normally.

[0030] In this embodiment, the second heating resistor element 402 can sufficiently heat the temperature detection element 115 and the liquid around the temperature detection element 115, thereby making it possible to increase the temperature change of the temperature detection element 115 and obtain higher sensitivity.

[0031] (Third embodiment) A third embodiment will be described with reference to Figure 6. Figure 6(a) is a schematic plan view of a liquid ejection head. Figure 6(b) is a schematic cross-sectional view of liquid ejection head 118 taken along line E-E' in Figure 6(a). Figure 6(c) is a schematic cross-sectional view of liquid ejection head 118 taken along line F-F' in Figure 6(a). In the third embodiment, an example of a configuration in which high sensitivity or additional functionality can be achieved by detecting different phenomena using different temperature detection elements will be described.

[0032] In the third embodiment, a second temperature detection element 605 is disposed on the heating resistor element 102 via an insulating layer 101. The second temperature detection element 605 is connected to a signal wiring 607 via a via 606. The second temperature detection element 605 is formed as a single layer or a multilayer of a metal material or alloy with a large temperature coefficient of resistance, such as iridium, tantalum, titanium, tungsten, silicon, tantalum silicon nitride, or tungsten silicon nitride. The second temperature detection element 605 may have a cavitation-resistant function. The second temperature detection element 605 can be disposed without increasing manufacturing costs by using the same material as the first temperature detection element 115 and processing them in the same process. The signal wiring 607 is formed of a metal material primarily composed of, for example, aluminum or copper. The via 606 is formed of a metal material primarily composed of, for example, tungsten or copper.

[0033] Specific examples of methods for discharging liquid and detecting the temperature using a temperature detection element will be described with reference to FIGS. 7 and 8. FIG. 7 is a schematic diagram illustrating the operating principle of this embodiment. FIG. 7(a) is a waveform diagram of a drive pulse applied to the first heating resistor element 102. FIG. 7(b) is a diagram illustrating changes in the liquid flow rate over time when the direction from the supply port 108 to the discharge port 111 shown in FIG. 6 is defined as positive. FIG. 7(c) is a waveform diagram of a current applied to the second heating resistor element 402. FIG. 7(d) is a waveform diagram of a current applied to the first temperature detection element 115. FIG. 7(e) is a waveform diagram of the output voltage of the first temperature detection element 115 corresponding to changes in liquid temperature. FIG. 7(f) is a waveform diagram of a current applied to the second temperature detection element 605. FIG. 7(g) is a waveform diagram of the output voltage of the second temperature detection element 605 corresponding to changes in liquid temperature.

[0034] Figure 8 is a schematic diagram for explaining the behavior of the liquid in the bubbling chamber during the ejection operation in this embodiment. To make it easier to understand their positional relationships, the first heating resistor element 302, first temperature detection element 315, second temperature detection element 805, and bubbling chamber 312 are shown schematically. Figure 8(a) shows the behavior during normal ejection, and Figure 8(b) shows the behavior during a typical ejection failure.

[0035] The behavior during normal ejection will be described with reference to FIG. 8(a). Starting from the steady state (tA), when a drive pulse is applied to the first heating resistor element 302, boiling occurs above the first heating resistor element 302 in the liquid in the bubble-forming chamber, causing a bubble to grow (tB). When the pulse application ends, the bubble disappears. As the liquid disappears, the front part of the liquid separates, and the separated part flies through the air as a droplet, landing, for example, on a recording medium. The remaining part of the liquid, excluding the separated part, retreats into the bubble-forming chamber due to the negative pressure generated when the bubble disappears. This is called the tailing liquid, or part of the ejected droplet, and falls onto the second temperature detection element 805 (tC). As shown in FIG. 7(g), when part of the ejected droplet falls onto the second temperature detection element 805, the second temperature detection element 805 rapidly cools, causing a sudden change in the output voltage of the second temperature detection element 805. Next, when the liquid is refilled, the liquid interface moves toward the ejection port 111. This is caused by capillary force within the bubble-forming chamber. 7(b), when the bubbling operation is performed, the liquid first flows toward the supply port 108, and then, once the bubble volume reaches a maximum, flows toward the discharge port 111. When the refilling of the liquid is completed, the state returns to a steady state (tD).

[0036] The behavior during non-ejection will be explained with reference to Figure 8(b). When a drive pulse is applied to the heating resistor element 302, a boiling phenomenon occurs and bubbles grow, but the liquid does not separate. When liquid is not ejected in this way, as shown in Figure 7(g), no liquid tail or part of the ejected droplet falls off, and the temperature drops gently.

[0037] The liquid temperature during normal and non-discharge conditions also produces a difference in the detected output voltage, as shown in Figures 7(e) and (g), making it possible to determine whether the liquid is being discharged normally.

[0038] In this embodiment, two temperature detection elements are used to determine the temperature change caused by whether or not some of the ejected droplets have fallen onto the second temperature detection element. Specifically, two different phenomena are detected: the output of the second temperature detection element 605 and the output of the first temperature detection element 115, which determines the temperature change caused by differences in the liquid refill speed. This makes it possible to consistently achieve high sensitivity without being affected by structural differences or external factors, thereby improving detection accuracy. It is also possible to use the second temperature detection element 605 to determine whether ejection is occurring normally, and to add separate functions to the first temperature detection element 115, such as the liquid flow rate and the presence or absence of liquid.

[0039] In this embodiment, an example has been given in which the first temperature detection element 115 is heated by the second heating resistance element 402, but this is not limitative, and heating by the second heating resistance element 402 is not necessarily required. In particular, when the first temperature detection element 115 is close to the first heating resistance element 102, heating by the first heating resistance element 102 may be sufficient.

[0040] (Fourth embodiment) A fourth embodiment will be described with reference to Figure 9. Figure 9(a) is a schematic plan view of a liquid ejection head. Figure 9(b) is a schematic cross-sectional view of the liquid ejection head taken along line G-G' in Figure 9(a). Figure 9(c) is a schematic cross-sectional view of the liquid ejection head taken along line H-H' in Figure 9(a). In the fourth embodiment, an example of a configuration in which sensitivity is further increased by increasing the resistance of the temperature detection element will be described.

[0041] If the resistance of the temperature detection element is too low, it will not be possible to obtain sufficient voltage for circuit operation, resulting in reduced sensitivity. Therefore, it is desirable for the temperature detection element to have an appropriate resistance value.

[0042] In the fourth embodiment, the resistance value is increased by arranging the second temperature detection element 905 in a folded manner multiple times. Although not shown, the second temperature detection element 905 may also be arranged in a single line like a bridge in a horizontal direction in a plan view. The second temperature detection element 905 may also be arranged vertically in the center of the heating resistor element 102, which has a relatively high temperature. In this case, the second temperature detection element 905 cannot be expected to have anti-cavitation properties, but it can be used in liquid ejection heads where a relatively short lifespan is acceptable. Although not shown, the resistance value of the first temperature detection element 115 can also be increased using a similar method.

[0043] In this embodiment, the resistance value of the temperature detection element can be increased, so that higher sensitivity can be obtained.

[0044] (Fifth embodiment) With reference to Figure 10 Fifth An embodiment will be described. Fig. 10(a) is a schematic plan view of a liquid ejection head. Fig. 10(b) is a schematic cross-sectional view of the liquid ejection head taken along line J-J' in Fig. 10(a). Fig. 10(c) is a schematic cross-sectional view of the liquid ejection head taken along line K-K' in Fig. 10(a). In the fifth embodiment, an example of a configuration in which increased sensitivity or additional functionality can be achieved by increasing the number of temperature detection elements will be described.

[0045] In the fifth embodiment, a first temperature detection element 115 and a third temperature detection element 1015 are disposed outside the heating resistor element 102. The third temperature detection element is disposed on the opposite side of the first temperature detection element 115, with the ejection port as the boundary. More preferably, the first temperature detection element 115 and the third temperature detection element 1015 are disposed approximately symmetrically with the ejection port 111 as the center. The third temperature detection element 1015 is connected to a signal wiring 1017 (not shown) via a via 1016. The third temperature detection element 1015 is formed as a single layer or a multilayer of a metal material or alloy with a large temperature coefficient of resistance, such as iridium, tantalum, titanium, tungsten, silicon, tantalum silicon nitride, or tungsten silicon nitride. The third temperature detection element 1015 can be disposed without increasing manufacturing costs by using the same material as the first temperature detection element 115 and processing it in the same process. The via 1016 is formed of a metal material primarily composed of, for example, tungsten or copper. Since the number of temperature detection elements is increased in this way, higher sensitivity can be obtained by adding the outputs, for example.

[0046] A specific example of a method for discharging liquid and detecting the temperature using a temperature detection element will be described with reference to Fig. 11. Fig. 11 is a schematic diagram for explaining the behavior of liquid in the bubbling chamber during the discharging operation in this embodiment. To make it easier to understand the positional relationships, the heating resistance element 302, first temperature detection element 315, second temperature detection element 805, third temperature detection element 1115, and bubbling chamber 312 are shown in schematic form.

[0047] Referring to Figure 11, we will explain the behavior of ejection that results in a defective image. Starting from a steady state (tA), when a drive pulse is applied to the heating resistor element 302, boiling occurs above the heating resistor element 302 in the liquid in the bubble-forming chamber, causing bubbles to grow (tB). When the pulse application ends, the bubbles disappear. As the liquid disappears, the front part of the liquid separates, flying as droplets through the air and landing, for example, on a recording medium. The remaining liquid, excluding the separated part, retreats into the bubble-forming chamber due to the negative pressure generated when the bubbles disappear. This is called tailing liquid, or part of the ejected droplet, and falls onto the second temperature detection element 805. As shown in Figure 11(tC), if there is foreign matter, such as paper dust, near the ejection port 111, the droplet will fly at an angle and land on the recording medium at a location different from the intended location. Such a misaligned landing on the recording medium results in a defective image. It is also known that when droplets fly at an angle, the landing position of some of the ejected droplets will also be misaligned. If the landing position of some of the ejected droplets is shifted, a difference will occur in the refill speed of the liquid in the directions of the arrows Q and R. In this way, by subtracting the output of the first temperature detection element count of 115 from the third temperature detection element count of 1015, for example, it is possible to add a function that detects ejections that land in shifted positions, which will result in poor image quality even though the droplets are ejected.

[0048] 10(b) in the direction of arrow Q, the liquid is heated by applying a current to the heating resistor element 102 that is low enough to prevent the liquid from bubbling. After that, by obtaining the difference in output between the first temperature detection element 115 and the third temperature detection element 1015, it is possible to add a function to detect the circulation speed.

[0049] In this embodiment, two temperature detection elements are used on the outer side of the heating resistance element 102, but the number is not limited to this and may be three or more. [Explanation of symbols]

[0050] 100 base 101 Protective layer 102 heating element 108 Liquid supply port 111 Discharge port 115 Temperature detection element 118 Liquid ejection head

Claims

1. an insulating layer disposed on a substrate; a heat generating resistor element disposed within the insulating layer and configured to generate thermal energy for discharging the liquid; a foaming chamber provided above the insulating layer for foaming a liquid based on the thermal energy; a first temperature detection element capable of detecting a temperature inside the foaming chamber, the first temperature detection element is disposed between the heating resistor element and the bubbling chamber in a thickness direction of the base, and on a conductive layer that is closest to the bubbling chamber among a plurality of conductive layers provided on the insulating layer; the first temperature detection element is disposed outside of the area directly above the heating resistor element in a plan view, and is disposed within the bubbling chamber; The first temperature detection element is heated before detection by a means different from that of the heating resistor element. A liquid ejection head characterized by:

2. an insulating layer disposed on a substrate; a heat generating resistor element disposed within the insulating layer and configured to generate thermal energy for discharging the liquid; a foaming chamber provided above the insulating layer for foaming a liquid based on the thermal energy; a first temperature detection element and a second temperature detection element capable of detecting a temperature inside the bubble-forming chamber, for at least each of the heating resistance elements; the first temperature detection element and the second temperature detection element are disposed between the heating resistor element and the bubbling chamber in a thickness direction of the base, and on a conductive layer that is closest to the bubbling chamber among a plurality of conductive layers provided on the insulating layer; the first temperature detection element is disposed outside of the area directly above the heating resistor element in a plan view, and is disposed within the bubbling chamber; At least a portion of the second temperature detection element is disposed directly above the heating resistance element in a plan view. A liquid ejection head characterized by:

3. The first temperature detection element is heated before detection by a means different from that of the heating resistor element.

3. The liquid ejection head according to claim 2.

4. The first temperature detection element is heated by passing a current through the first temperature detection element.

4. The liquid ejection head according to claim 1, wherein the ink is a liquid having a thickness of 100 nm or less.

5. When the heating resistor element is a first heating resistor element, a second heating resistor element is provided below the first temperature detection element in the thickness direction of the base via an insulating layer, The first temperature detection element is heated by passing a current through the second heating resistor element.

4. The liquid ejection head according to claim 1, wherein the ink is a liquid having a thickness of 100 nm or less.

6. The heating of the first temperature detection element is controlled to a degree that does not cause the liquid to bubble.

4. The liquid ejection head according to claim 1, wherein the ink is a liquid having a thickness of 100 nm or less.

7. The second temperature detection element has a cavitation resistance function.

3. The liquid ejection head according to claim 2.

8. The first temperature detection element is made of the same material as the anti-cavitation membrane.

8. The liquid ejection head according to claim 1, wherein the liquid ejection head is a liquid ejection head.

9. The first temperature detection element and the second temperature detection element determine the liquid ejection state.

8. The liquid ejection head according to claim 2 or 7.

10. a third temperature detection element capable of detecting a temperature inside the foaming chamber; the third temperature detection element is disposed between the heating resistor element and the bubbling chamber in a thickness direction of the base, and on a conductive layer that is closest to the bubbling chamber among a plurality of conductive layers provided on the insulating layer, The third temperature detection element is disposed outside the area directly above the heating resistor element in a plan view, and is disposed within the bubbling chamber.

10. A liquid ejection head according to claim 2, 7 or 9.

11. The third temperature detection element is disposed on the opposite side of the first temperature detection element across the discharge port for discharging the liquid.

11. The liquid ejection head according to claim 10.

12. The third temperature detection element is disposed at a position symmetrical to the first temperature detection element with respect to the ejection port.

12. The liquid ejection head according to claim 11.

13. The third temperature detection element is formed of the same material as the first temperature detection element.

13. The liquid ejection head according to claim 10, wherein the liquid ejection head is a liquid ejection head.

14. The first temperature sensing element and the third temperature sensing element detect the velocity of the liquid.

14. The liquid ejection head according to claim 10, wherein the liquid ejection head is a liquid ejection head.

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