Liquid ejection head

Abstract

A liquid ejection head is provided that can achieve a desired circulation efficiency and maintain a circulation flow rate while shortening a circulation flow path to reduce the substrate size. [Solution] A liquid ejection head is used that has an ejection port, a pressure chamber, an individual ejection unit having a first energy generating element provided in the pressure chamber and generating thermal energy, and a second energy generating element provided in an individual flow path and generating thermal energy, and a common flow path that supplies liquid to the individual flow paths, in which the direction in which the ejection port row is arranged is perpendicular to the direction in which the individual flow paths extend, and that has a structure that increases the flow resistance between the first energy generating element and the second energy generating element.

Description

[Technical Field]

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

[0002] Circulation-type liquid ejection devices are known that circulate ink in a liquid ejection head (hereinafter also referred to as the "head") to expel air bubbles from the flow path and prevent ink from thickening near the ejection ports. A well-known method of circulating ink is a method using a pressure difference (hereinafter also referred to as the "differential pressure method"). This method uses a pressure adjustment mechanism or the like to increase the pressure on the side that supplies ink to the ejection ports (the "inside") compared to the side that recovers ink (the "outside"), thereby causing ink to flow from the "inside" to the "outside." To circulate the ink, the ink that has flowed to the "outside" must be returned to the "inside," which requires a pump as a mechanism. Some liquid ejection devices circulate the liquid between the liquid ejection head and the main body by installing a pump outside the head, such as the recording device main body, while others circulate the liquid within the liquid ejection head by installing a pump inside the liquid ejection head. However, such a differential pressure method requires mechanisms such as a pressure adjustment mechanism and a pump, which can lead to an increase in the size of the recording device main body and the head.

[0003] Therefore, ink circulation methods other than the differential pressure method have been investigated. Specifically, a circulation flow path that communicates with the ejection port is provided, and an energy generating element (hereinafter also referred to as a "flow energy generating element") that is separate from the energy generating element for ejecting ink (hereinafter also referred to as an "ejection energy generating element") is arranged in the circulation flow path, and the ink is circulated in the circulation path by driving the flow energy generating element.

[0004] Patent Document 1 discloses a configuration in which a circulation flow path is provided that extends so as to intersect with an array of ejection ports in which a plurality of ejection ports are arranged, and a flow energy generating element is provided in the circulation path. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2020-104312 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, in Patent Document 1, in order to optimize the circulation efficiency of the flow energy generating elements and maximize the circulation flow rate, it is necessary to lengthen the circulation flow path, which increases the size of the substrate on which the energy generating elements are mounted, and therefore the head size and recording device size.On the other hand, simply shortening the circulation flow path will result in a problem of a deterioration in the circulation efficiency of the flow energy generating elements and a decrease in the circulation flow rate.

[0007] The present invention has been made in view of the above-mentioned problems, and has an object to provide a liquid ejection head that can achieve a desired circulation efficiency and maintain a circulation flow rate while shortening the circulation flow path and reducing the substrate size. [Means for solving the problem]

[0008] In order to solve the above problems, the liquid ejection head of the present invention comprises: a pressure chamber communicating with the discharge port; and a first energy source provided in the pressure chamber and generating thermal energy for discharging the liquid from the discharge port. an individual discharge unit including a heat generating element, an individual flow path communicating with the pressure chamber, and a second energy generating element provided in the individual flow path and generating thermal energy; a common flow path that supplies liquid to the individual flow paths of the plurality of individual discharge units; A liquid ejection head having a plurality of the ejection ports included in a plurality of the individual ejection units form an ejection port array, In the individual flow path of the individual discharge unit, the first energy generating element and the second energy generating element are arranged in a direction intersecting the discharge port array, the individual flow paths extend in a direction intersecting the ejection port array so that both ends of the individual flow paths are positioned on either side of the ejection port array; The individual flow paths are provided with a resistance structure that increases the flow resistance between the first energy generating element and the second energy generating element. It is characterized by: [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a liquid ejection head that can achieve a desired circulation efficiency and maintain a circulation flow rate while shortening the circulation flow path and reducing the substrate size. [Brief explanation of the drawings]

[0010] [Figure 1] Overall view of a device using a liquid ejection head [Figure 2] Overall view of a liquid ejection head and an overall view of a liquid ejection chip [Figure 3] Schematic diagram of the vicinity of the ejection port of the liquid ejection head [Figure 4] Schematic diagram of the vicinity of the ejection port of the liquid ejection head [Figure 5] Schematic diagram of the vicinity of the ejection port of the liquid ejection head [Figure 6] Schematic diagram of the vicinity of the ejection port of the liquid ejection head according to the first embodiment. [Figure 7] 1 is a schematic diagram of the entire vicinity of a discharge port of a liquid discharge head according to a first embodiment; [Figure 8] Circulation flow rate graph in some examples of the first embodiment [Figure 9] Schematic diagram of the vicinity of the ejection port of the liquid ejection head according to the second embodiment. [Figure 10] 10 is a schematic diagram of the vicinity of the ejection port of the liquid ejection head according to the third embodiment; [Figure 11] 10 is a schematic diagram of the vicinity of the ejection port of the liquid ejection head according to the fourth embodiment; [Figure 12] 13 is a schematic diagram of the vicinity of the ejection port of the liquid ejection head according to the fifth embodiment; [Figure 13] Circuit configuration diagram in the first embodiment DETAILED DESCRIPTION OF THE INVENTION

[0011] Preferred embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. Note that the following embodiments do not limit the scope of the present disclosure, and not all combinations of features described in the present embodiments are necessarily essential to the solutions of the present disclosure. Note that identical components are designated by the same reference numerals. In the following description, the basic configuration of the present disclosure will first be described, followed by a description of the features of the present disclosure.

[0012] <Liquid discharge device> First, a schematic configuration of a liquid ejection device 50 in this embodiment will be described. FIG. 1 is an enlarged view of a liquid ejection head 1 of the liquid ejection device 50 and its surroundings, and FIGS. 1(a) and 1(b) are perspective views schematically showing a liquid ejection device using a liquid ejection head. The liquid ejection device 50 shown in FIG. 1 is a liquid ejection device (serial type liquid ejection device) that performs image recording by ejecting liquid onto a recording medium P using a liquid ejection head that scans in a direction intersecting the conveyance direction of the recording medium P. The present invention is not limited to serial type liquid ejection devices, but can also be applied to page-wide type liquid ejection devices that perform image recording by ejecting liquid onto a recording medium conveyed in the conveyance direction using a line head (page-wide type head) that is long in the page width direction of the recording medium. The liquid ejection head in this embodiment is capable of ejecting four types of ink: black (K), cyan (C), magenta (M), and yellow (Y). It is possible to record a full-color image using these inks. The inks that can be ejected from the liquid ejection head are not limited to the above four types of ink. The present disclosure is also applicable to liquid ejection heads for ejecting other types of ink. In other words, there are no limitations on the types and number of inks that can be ejected from the liquid ejection head.

[0013] In a serial type liquid ejection device 50, the liquid ejection head 1 is mounted on a carriage 60. The carriage 60 moves back and forth in the main scanning direction (X direction) along a guide shaft 62. The recording medium is transported in a sub-scanning direction (Y direction) that intersects (in this example, orthogonal to) the main scanning direction by transport rollers (transport means) 55, 56, 57, and 58. Note that in each figure referred to below, the Z direction indicates the vertical direction, and intersects (in this example, orthogonal to) the XY plane defined by the X and Y directions.

[0014] FIG. 1(a) shows a configuration in which a main ink tank 2 serving as a liquid storage unit is provided outside the liquid ejection head. The liquid (ink) stored in the ink tank 2 is supplied to a sub-ink tank 54 on the liquid ejection head 1 side via an ink supply tube (liquid communication path) 59 or the like by the driving force of an external pump 28. On the other hand, FIG. 1(b) shows a configuration in which an ink tank 54 is provided directly above the liquid ejection head 1 (without a main ink tank 2 serving as a liquid storage unit outside the liquid ejection head). In this case, the liquid ejection head 1 may be provided integrally with the ink tank 54 and configured to be removable / attachable to / from a carriage 60, or the liquid ejection head 1 may be provided integrally with the carriage 60 and only the ink tank 54 may be removable / attachable. The following explanation will use the configuration of FIG. 1(a) as a representative example.

[0015] The liquid ejection head 1 is configured to include individual ejection units, which will be described later (see FIG. 2). The specific configuration will be described later, but each individual ejection unit is provided with an ejection port for ejecting liquid, a pressure chamber communicating with the ejection port, a first energy generating element (ejection energy generating element) that is provided in the pressure chamber and generates energy for ejecting liquid from the ejection port, an individual flow path that communicates with the pressure chamber, and a second energy generating element (flow energy generating element) that is provided in the individual flow path. The liquid ejection head 1 has a plurality of individual ejection units, and each individual ejection unit has a supply flow path for supplying liquid to the individual flow path in the individual ejection unit.

[0016] When using a liquid ejection head, the evaporation of volatile components such as water from the ejection orifices and the resulting concentration of solids near the ejection orifices can sometimes cause unstable liquid ejection. Various methods have been developed to prevent this. For example, a liquid ejection device can be provided with a cap member (not shown) located in the X direction away from the recording medium transport path, which can cover the ejection orifice surface of the liquid ejection head. The cap member is used to cover the ejection orifice surface of the liquid ejection head to prevent the orifices from drying out and protect them when not performing printing operations. An ink suction mechanism (not shown) can also be provided, in which case the cap member is used to suction ink from the orifices. This ink suction operation refreshes the ink near the orifices, maintaining the quality of the resulting image. Other known methods include performing a preliminary ejection (pre-ejection) when not performing printing to discard concentrated ink, and performing a preliminary ejection of ink (paper preliminary ejection / intra-page preliminary ejection) on the recording medium during printing operations at a location and amount that is inconspicuous in terms of image quality. Although these methods contribute greatly to improving image quality, they require some ink to be discarded in order to refresh the ejection ports, and therefore it is necessary to reduce the amount of wasted ink as much as possible.

[0017] To address this issue, by providing a second energy generating element (flow energy generating element) in the individual flow path and circulating the ink within the flow path, it is possible to suppress the drying of the ejection port and the concentration of ink near the ejection port while suppressing the amount of waste ink. Furthermore, if the number of times preliminary ejection and other operations can be reduced to the minimum, this will also lead to improvements in throughput and yield.

[0018] The second energy generating element (flow energy generating element) does not need to be provided in all of the individual discharge units of the liquid discharge head. If it is provided in some of the individual discharge units, the above-mentioned effects can be obtained compared to when it is not provided.

[0019] 1(a) may be configured so that all of the locations corresponding to the four types of ink are provided with second energy generating elements, or so that only the locations corresponding to one type of ink are provided with second energy generating elements. In other words, the liquid ejection head may be configured so that only at least one type of ink is circulated, rather than all four types of ink.

[0020] <Basic configuration of liquid ejection head> Fig. 2(a) is an exploded perspective view of the liquid ejection head of this embodiment. As shown in Fig. 2, the liquid ejection head is configured to include a sub-ink tank 54 that temporarily stores ink in the head, and a liquid ejection chip 3 that ejects ink supplied from the sub-ink tank 54 onto a recording medium P. The liquid ejection head of this embodiment is fixedly supported on the carriage of the liquid ejection device by positioning means and electrical contacts (not shown) that are provided on the carriage. The liquid ejection head ejects ink while moving together with the carriage in the main scanning direction (X direction) shown in Fig. 1, and performs recording on the recording medium P.

[0021] An ink supply tube 59 is provided to the external pump 28, which is connected to the ink tank 2, which serves as the ink supply source (see FIG. 1( a)). A liquid connector (not shown) is provided at the end of this ink supply tube. When the liquid ejection head 1 is mounted on the liquid ejection device 50, the liquid connector provided at the end of the ink supply tube 59 is liquid-tightly connected to a liquid connector insertion port, which is a liquid inlet port provided in the head housing of the liquid ejection head 1. This forms an ink supply path from the ink tank 2 to the liquid ejection head 1 via the external pump 28. In this embodiment, four types of ink are used, so four sets of ink tanks 2, external pumps 28, ink supply tubes 59, and sub-ink tanks 54 are provided, one for each ink, and four independent ink supply paths are formed corresponding to each ink. In this way, the liquid ejection device of this embodiment is provided with an ink supply system to which ink is supplied from the ink tank 2 provided outside the liquid ejection head 1. Note that the liquid ejection device of this embodiment is not provided with an ink recovery system that recovers ink in the liquid ejection head back to the ink tank. Therefore, the liquid ejection head is provided with a liquid connector insertion port for connecting the ink supply tube of the ink tank, but is not provided with a connector insertion port for connecting a tube for recovering ink from the liquid ejection head to the ink tank. Note that a liquid connector insertion port is provided for each ink.

[0022] Figures 2(b), (c), and (d) are overall views of the liquid ejection chips that make up a liquid ejection head. Figure 2(b) shows a configuration of one chip for four colors, Figure 2(c) shows a configuration of one chip for two colors, and Figure 2(d) shows a configuration of one chip for one color. Each liquid ejection chip is provided with ejection ports and pads used for electrical mounting. Figure 2(a) shows the chip configuration of Figure 2(b).

[0023] FIG. 2(b) shows a first embodiment in which one chip is configured for four colors. The four colors are, for example, black, cyan, magenta, and yellow, and each color has its own column, which is aligned in the Y direction. The ejection openings in each column are adjacent to each other but offset in the X direction, and are equally spaced along the Y direction. However, the ejection openings in each column may be aligned in a single column along the Y direction without being offset in the X direction. Alternatively, black may be arranged in two columns, for a total of five columns for the four colors.

[0024] 2(c) shows a second embodiment in which two chips are used, one chip for each of two colors. When mounting two chips on a liquid ejection head, two chips may be mounted on one liquid ejection head, or two heads may be prepared in which one chip is mounted on one liquid ejection head. Fig. 2(d) shows a third embodiment in which four chips are used, one for each color. As in Fig. 2(c), four chips may be mounted on one liquid ejection head, or four liquid ejection heads, each mounted with one chip, may be prepared.

[0025] Also, when the chip is divided into multiple parts, as shown in Figure 2(c)(d), not all of them need to be the same chip length. Also, various combinations of other colors for the chip are possible, and the same applies when the total number of colors is more than four.

[0026] <Components of the circulation unit> (Straight type) Fig. 3 is a schematic diagram illustrating the vicinity of the ejection ports of a straight-type liquid ejection head. In this specification, the term "straight-type" refers to a straight shape in which individual flow paths in which first energy generating elements (ejection energy generating elements) and second energy generating elements (flow energy generating elements) are arranged extend in a direction intersecting the ejection port array (in the case of Fig. 3, a direction perpendicular to the ejection port array) so that both ends of the individual flow paths are located on either side of the ejection port array. In other words, in the individual flow paths of the individual ejection units, the first energy generating elements and the second energy generating elements are arranged in a direction intersecting the ejection port array.

[0027] Fig. 3(a) is a plan view seen from the direction in which droplets are ejected from the ejection port. Fig. 3(b) is a cross-sectional view taken along line A-A' in Fig. 3(a). Fig. 3(c) is another cross-sectional view taken along line A-A' in Fig. 3(a). Fig. 3(d) is a diagram illustrating ink flow when the first energy generating element is driven.

[0028] 3(a) to 3(c), pressure chambers 12 are formed between a substrate 18 and an orifice plate 19, each separated by a partition wall 21 and corresponding to a respective ejection port 11, and individual flow paths 23 are formed for causing ink to flow through the pressure chambers 12. An ink meniscus is formed at the ejection port 11, forming an ejection port interface as an interface between the ink and the atmosphere.

[0029] The substrate 18 is provided with a first energy generating element 14 that generates energy to eject the ink in the pressure chamber. In this example, an electrothermal conversion element is used. The first energy generating element 14, together with the ejection port 11 and the pressure chamber 12, is located closer to the second supply opening 32 than to the first supply opening 22. By driving the first energy generating element 14 to generate heat and cause the ink in the pressure chamber 12 to bubble, the resulting bubble-generating energy can be used to eject ink from the ejection port 11.

[0030] The substrate 18 is also provided with a second energy generating element 24 that generates energy to cause the ink in the individual flow paths to circulate in a circulating flow 27 indicated by the arrows. In this example, an electrothermal conversion element is used. Therefore, the second energy generating element 24 is also referred to as a circulation heater 24.

[0031] Furthermore, the substrate 18 is provided with an opening for supplying liquid from the common flow path to the individual flow paths. This opening may be configured to have multiple openings (independent supply openings) as shown in Figure 3(a), or may be a supply groove as a single large opening. The second energy generating element 24 is located closer to the first supply opening 22 than the second supply opening 32.

[0032] The individual flow paths 23 intersect (in this example, perpendicular to) the direction in which the discharge ports are aligned in a row (first direction). 3(b) 。 Individual flow path 23 includes a pressure chamber 12, an inlet (upstream) side connecting flow path 13 in FIG. 3(b) that communicates with one end of the pressure chamber 12, and an outlet (downstream) side flow path in FIG. 3(b) that communicates with the other end of the pressure chamber 12. The individual flow path 23 communicates at one upstream end and the other downstream end with a first supply opening 22 and a second supply opening 32 that penetrate the substrate 18, respectively. Therefore, the connecting flow path 13 is located on the second energy generating element side of the ejection port array. Both ends of the individual flow path 23 are located on opposite sides of the ejection port array. The first supply opening 22 and the second supply opening 32 are supplied with liquid from a common flow path 38.

[0033] The ink flows in the individual flow paths are broadly classified into two types: (1) a first ink flow for driving the first energy generating element 14 and refilling after ejection, and (2) a second ink flow for driving the second energy generating element 24 and forming a circulating flow.

[0034] When the first energy generating element 14 is driven and liquid is ejected from the ejection port 11, ink is supplied from the first supply opening 22 and the second supply opening 32 as shown in Figure 3(d), and ink flows into the pressure chamber from both supply openings.

[0035] When the second energy generating element 24 is driven to form a circulating flow, ink flows into the individual flow path 23 through the first supply opening 22, which is on the connecting flow path side, and flows out to the outside through the second supply opening 32, which is not on the connecting flow path side. In this example, ink flowing out from the second supply opening 32 is returned to the first supply opening 22 and circulated, thereby forming a circulating flow 27, indicated by the arrow, in the individual flow path 23. Note that FIG. 3(b) shows a configuration in which the first supply opening 22 and the second supply opening 32 are shared within the chip. Also, FIG. 3(c) shows a configuration in which the first supply opening 22 and the second supply opening 32 are connected to individual flow paths and shared outside the recording head; either configuration is acceptable.

[0036] (Pump principle) FIG. 4 illustrates the principle of the generation of a circulating flow of ink when a second energy generating element (circulation heater) 24, which is an electrothermal conversion element, is used. FIGS. 4(a), 4(b), and 4(c) are cross-sectional views similar to FIG. 3(b), respectively illustrating the generation, growth, contraction, and post-death processes of a bubble B caused by film boiling of ink when ink is heated by the circulation heater 24. In FIG. 4(a), the circulation heater 24 is located closer to the first supply opening 22 than the second supply opening 32. Therefore, the flow resistance R1 between the circulation heater 24 and the first supply opening 22 is smaller than the flow resistance R2 between the circulation heater 24 and the second supply opening 32. FIG. 4(a) also includes an equivalent circuit that expresses these flow resistances R1 and R2 as electrical resistances. Due to the difference between the flow resistances R1 and R2, the bubble B generated by film boiling of ink grows toward the first supply opening 22, which has the smaller flow resistance R1, as shown in FIG. 4(a). Therefore, in the individual flow path 23, the flow Fa of ink toward the first supply opening 22 is larger than the flow Fb of ink toward the outflow flow path 15.

[0037] FIG. 4(b) is an explanatory diagram of the flow of ink during the contraction of bubble B. As bubble B contracts, ink flows in to compensate for the contracted volume. As shown in FIG. 4(b), the flow Fc of ink flowing in from the first supply opening 22 on the side with small flow resistance R1 is larger than the flow Fd of ink flowing in from the second supply opening 32 on the side with large flow resistance R2. Furthermore, the vanishing position of bubble B shifts from above the circulation heater 24 toward the second supply opening 32.

[0038] 4(c) is an explanatory diagram showing the process after the collapse of bubble B. Due to the relationship Fc>Fd that occurred in FIG. 4(b), a circulating flow F of ink is generated from the first supply opening 22 to the second supply opening 32.

[0039] The magnitude of the circulating flow F is affected by the ratio of flow resistances R1 and R2 and the size of the bubbles B. For example, assuming that a circulation heater 24, which is an electrothermal conversion element, is used as the second energy generating element 24, it is preferable that the second energy generating element 24 be positioned closer to one of the two ends of the individual flow path 23 than the first energy generating element. More specifically, it is preferable that the flow resistance ratio R1 / R2 be set in the range of 0.05 to 0.40. By setting the flow resistance ratio R1 / R2 in this range, the circulating flow F can be maximized. It is important for the circulating flow F to increase the ink flow Fa toward the first supply opening 22 and increase the ink flow Fc flowing in from the first supply opening 22, as shown in FIGS. 4(a) and 4(b). Therefore, it is effective to reduce the flow resistance R1. It is also important to minimize the ink flow Fb toward the outlet flow path 15 and reduce the ink flow Fd flowing in from the second supply opening 32. Therefore, it is effective to increase the flow resistance R2. For these reasons, it is important to reduce the flow resistance R1 and increase the flow resistance R2, that is, to reduce the flow resistance ratio R1 / R2. Furthermore, if the bubbles B are large, that is, if the bubble volume is large, this leads to an increase in the excluded volume of the fluid generated in the individual flow paths 23, and therefore the circulating flow F becomes larger.

[0040] As a means of increasing the bubble volume, ·Increased size of circulating heater 24 - Widen the width and height of the flow path 13 to reduce flow resistance -Reducing ink viscosity -Increased head temperature Double pulse drive pulse Examples include:

[0041] When part of the ink circulation flow F enters the ejection port 11, the concentrated ink in the ejection port 11 is sent to the second supply opening 32 side, and fresh ink flows into the ejection port 11 from the first supply opening 22 side through the connecting flow path 13. In this way, by making it difficult for the concentrated ink to accumulate in the ejection port 11, the influence of the concentrated ink can be suppressed and the initial ink ejection state can be maintained.

[0042] The circulating flow F is a transient flow that occurs during the growth and contraction process of the bubble B when it is generated. Therefore, after the bubble B collapses, the inertial flow attenuates over time and stops after a certain period of time. Therefore, to steadily generate the circulating flow F for a certain period of time, the heating element of the circulation heater 24 must be repeatedly driven. The driving cycle of the circulation heater 24 is not particularly limited as long as it can discharge the concentrated ink from the ejection port 11. However, because the circulating flow F is a transient flow that occurs during the growth and contraction process of the bubble B when it is generated, taking into account the 10 μs cycle from bubble generation to collapse, driving the circulation heater 24 at a high driving frequency, such as 100 kHz, reduces its effectiveness. Therefore, it is preferable to drive the circulation heater 24 at a frequency of, for example, 100 Hz to several tens of kHz. The higher the driving frequency, the more the circulating flow F is maintained, resulting in a greater discharge effect of the concentrated ink. However, at the same time, it is necessary to consider the increase in ink temperature due to heat generated by driving the circulation heater 24. Therefore, the circulation heater 24 must be driven at an appropriate frequency.

[0043] It is possible to consider a case where the second energy generating element responsible for circulation has a drive energy lower than the normal drive energy for ejection. In other words, the second energy generating element may be driven for circulation with a drive energy weaker than the drive energy for ejection of the first energy generating element. Even when the drive energy of the second energy generating element is reduced, the size and aspect ratio of the energy generating element can be adjusted accordingly.

[0044] (recirculation concentration) Figure 5 is a diagram to explain how ink concentration is eliminated as it circulates due to the second energy generating element. The individual flow paths have a straight configuration in which the inlet and outlet for the circulating flow are separated, and the areas where the ink is concentrated are shown in dark colors, with the degree of concentration expressed by the shade of light.

[0045] In Figure 5, Figure 5(a) shows the state after a temporary pause. During a temporary pause, volatile components evaporate from the ejection orifice, causing ink to concentrate near the orifice. Figure 5(b) shows the state immediately after a circulating flow is subsequently generated by the second energy generating element. The circulating flow eliminates the concentration near the orifice. The ink that has concentrated near the orifice is discharged from the outlet, and concentration is eliminated throughout the individual flow channels. Figure 5(c) shows the state after another temporary pause. As in Figure 5(a), ink concentration again progresses near the orifice. Figure 5(d) shows the state immediately after a circulating flow is then generated by the second energy generating element. As in Figure 5(b), concentration near the orifice is again eliminated, and concentration is eliminated throughout the individual flow channels. As described above, in a straight-type inkjet printer in which the inlet and outlet of the individual flow channels are separated, the concentration state is reset each time the temporary pause and circulation operation are repeated.

[0046] As described above, in the straight type where the inlet and outlet of the circulation flow in the individual flow paths are separated, the concentration state can be reset for the entire individual flow path with each circulation operation, so the influence of concentration is unlikely to occur continuously and stably with circulation. Therefore, there is a structural feature that makes it difficult for the ejection stability to be reduced due to concentrated ink.

[0047] (ink) As described above, by using the second energy generating element to generate an ink circulation flow in the individual flow paths, it is possible to suppress the effects of concentrated ink that has thickened due to evaporation at the ejection port. In other words, the ink ejection state can be maintained in a good condition, which further reduces the effects of changes in ejection speed and makes it easier to stabilize ejection.

[0048] On the other hand, depending on the application of the liquid ejection head and the liquid ejection device equipped with the head, inks with different types of colorants and solid content are expected to be used. In other words, maintaining a high level of ejection stability regardless of the ink used is desirable for liquid ejection head performance. For example, to address issues that can arise from water in the ink, such as curling (warping) and cockling (wavy wrinkles) on plain paper, inks with reduced water content can be used. Inks with low water content have a high concentration of solids, such as organic solvents, pigments, and resins, and are prone to a rapid increase in viscosity as the water evaporates, leading to a decrease in ink ejection stability. For such inks, the method of generating a circulating flow within a pressure chamber, as described in the present invention, is very effective because it can suppress the increase in ink viscosity. Generally, inks with a high solid content are defined as those with a solid content of 10 wt% or more. In other words, the present invention is preferably applied to inks with a solid content of 10 wt% (mass%) or more.

[0049] Furthermore, the head operating temperature can be controlled by placing heaters over the entire chip and controlling them to maintain a constant temperature. Since ink viscosity changes depending on the temperature, the ink viscosity at the head operating temperature affects ejection stability.

[0050] When a circulating flow is formed using the second energy generating element, the instantaneous circulating flow velocity can be several tens of mm / s to 1000 mm / s. The average flow velocity over a time span of several hundreds of microseconds depends on the drive frequency of the circulating heater. This is because the circulating heater generates a transient circulating flow that decays over time and stops after a certain period of time. The average flow velocity is approximately 10 to 2 times the drive frequency (discharge frequency) of the first energy generating element. When driven at around 0 kHz, the average flow velocity can be several mm / s to 100 mm / s.

[0051] When using ink with a high pigment concentration, for example, ink with a viscosity of 3 cP to 6 cP at the head operating temperature, the ink tends to thicken at the nozzle opening depending on the non-ejection time (rest time). This can easily cause changes in ejection speed and lead to a decrease in ejection stability. Therefore, it is necessary to circulate the ink while the rest time is short, and it is necessary to eliminate concentration by performing regular or transient ink circulation at high frequency. When a circulation heater is used as the second energy generating element, transient ink circulation occurs, so performing circulation at high frequency can contribute to eliminating concentration at the nozzle opening.

[0052] On the other hand, when using ink with a low pigment concentration—for example, ink with a viscosity of 1 cP or more but 2 cP or less at the head operating temperature—the ejection speed may change depending on the non-ejection time (pause time), but the effect is relatively small compared to that of high-concentration ink. On the other hand, if the pause time is long, for example, the ink at the ejection port increases in viscosity depending on the non-printing operation time (stop time). Therefore, when restarting after a period of no printing and stopping, recovery procedures involving waste ink, such as suction, wiping, and preliminary ejection combined with these, are required. When a circulation heater is used as the second energy generating element, the recovery procedure creates a circulation flow, contributing to the elimination of condensation at the ejection port without generating waste ink. Depending on the pause time, it is possible to prevent the generation of waste ink by recovery procedures using only circulation operations. Alternatively, recovery procedures using circulation operations can be combined with suction operations to remove air bubbles in the head, separate from the elimination of condensation, to minimize waste ink generation.

[0053] Whether the ink is high-concentration or low-concentration, it is desirable to return the ink to its original, fresh state as much as possible in order to suppress the effects of concentrated ink. Therefore, even when a circulation heater is used as the second energy generating element, the lower the effects of recirculation concentration, the better the circulation effect can be obtained. In other words, the straight-type configuration is most effective.

[0054] (First embodiment) Figures 6 and 7 are schematic diagrams illustrating in detail the vicinity of the ejection ports of a liquid ejection head that ejects liquid such as ink in the first embodiment. Figures 6(a) to 6(c) are plan views of the individual flow path portion as viewed from the direction in which droplets are ejected from the ejection ports. Figures 6(d) to 6(f) are cross-sectional views of Figures 6(a) to 6(c), respectively.

[0055] Fig. 7(a) is an overall plan view of Fig. 6(c). Figs. 7(b) and (c) are two examples of AB cross sections of Fig. 7(a). Figs. 7(b) and (c) show two examples because the shape of the back side of the substrate changes depending on the type of etching method used for the substrate, but either shape of the cross section is acceptable.

[0056] 6 and 7, an ejection port 11 for ejecting liquid is formed in an orifice plate 19. A first energy generating element 14 is formed directly below the ejection port 11 in a substrate 18. A second energy generating element 24 is similarly formed on the substrate 18 together with the first energy generating element 14 to form a circulating flow 27 in an individual flow path 23. Liquid is supplied to the individual flow path 23 including the ejection port 11 from supply openings 22 and 32. At this time, both ends of the individual flow path are arranged separately at opposite positions in a second direction that is perpendicular to a first direction in which the ejection ports are arranged.

[0057] In the straight flow path shown in FIGS. 6 and 7, as described above, the second energy In this example, a circulation flow is used by placing the energy generating elements 24 in asymmetric positions. In this case, the side of the individual flow path end from the second energy generating element 24 with lower flow resistance is the inlet (upstream), and the side of the individual flow path end from the second energy generating element 24 with higher flow resistance is the outlet (downstream). Therefore, from the perspective of circulation flow rate, it is preferable to reduce the flow resistance on the inlet side from the second energy generating element 24 and increase the flow resistance on the outlet side from the second energy generating element 24. However, simply increasing the flow resistance on the outlet side from the second energy generating element 24 would increase the length of the individual flow path, which would increase the substrate size and head size. Therefore, from the perspective of circulation flow rate, it is preferable to increase the flow resistance on the outlet side from the second energy generating element 24 while shortening the flow path length.

[0058] On the other hand, among the flow resistances on the outlet side from the second energy generating element 24, it is preferable to reduce the flow resistance on the outlet side from the first energy generating element 14 because this is the main supply part that refills the amount of liquid ejected during ejection. Therefore, from the viewpoint of achieving both the circulation flow rate and the refill characteristics during ejection, it is preferable and important to increase the flow resistance between the first energy generating element 14 and the second energy generating element 24. In this case, it is also possible to obtain the effect of reducing interference (crosstalk) between the first energy generating element 14 and the second energy generating element 24.

[0059] Therefore, this embodiment is characterized by providing a high-resistance structure 51 in the center of the flow path between the first energy generating element 14 and the second energy generating element 24, as shown in FIG. 6(a). This reduces the flow resistance on the inlet side of the second energy generating element 24 and increases the flow resistance on the outlet side of the second energy generating element 24, thereby ensuring a sufficient circulation flow rate. Furthermore, by increasing the flow resistance between the first energy generating element 14 and the second energy generating element 24, the flow resistance on the outlet side of the first energy generating element 14 can be reduced, ensuring sufficient refill characteristics during ejection. In this way, by providing a region between the first energy generating element 14 and the second energy generating element 24 where the flow resistance is increased, both the circulation flow rate and the refill characteristics during ejection can be achieved. Here, the cross-sectional area in the circulation direction can also be interpreted as providing a region where the cross-sectional area is reduced. The high-resistance structure 51 is a type of resistance structure that increases the flow resistance between the first energy generating element 14 and the second energy generating element 24.

[0060] In this embodiment, the high-resistance structure 51 in the center of the flow path is shown as a cylindrical structure, but other pillar structures, such as a square pillar structure or a triangular pillar structure, may be used to increase flow resistance. Furthermore, the pillar structure may be elongated in the flow path direction, like a rounded rectangle when viewed from above, or multiple pillar structures may be used. However, regardless of the cross-sectional shape, a certain degree of effect can be achieved because the presence of the high-resistance structure 51 increases resistance compared to a state without it.

[0061] FIG. 6(b) shows a modified example in which filters 31 are provided on both sides of the individual flow paths. The filters 31 are used to prevent foreign matter contained in ink or the supply path from entering the individual flow paths. The filters 31 are placed at the connection points with the common flow path. This is a countermeasure to address the concern that if foreign matter gets mixed in near the first energy generating elements, ink may not be ejected from the ejection ports or may malfunction, degrading the image on the printed material. Similar to FIG. 6(a), FIG. 6(b) also makes it possible to achieve both the circulation flow rate and the refill characteristics during ejection. In the example of FIG. 6(b), filters 31 are placed upstream of the second energy generating elements 24 (closer to the first supply opening 22) and downstream of the first energy generating elements 14 (closer to the second supply opening 32).

[0062] FIG. 6(c) shows a modified example in which a filter 31 is provided only on the first energy generating element side of the individual flow path. This is because a high-resistance structure is provided on the opposite side of the individual flow path. Furthermore, compared to Figure 6(b), the flow resistance on the inlet side from the second energy generating element is smaller because the filter is no longer present. On the other hand, the flow resistance on the outlet side from the second energy generating element is larger because the filter remains. Therefore, from the perspective of circulation flow rate, this is even more preferable than Figure 6(b).

[0063] Figure 7(a) shows the overall configuration in which multiple flow paths are formed, using the flow path shown in Figure 6(c) as an example. A first supply opening 22 is provided on the inlet (upstream) side of the individual flow path, and a second supply opening 32 is provided on the outlet (downstream) side of the individual flow path. This allows multiple ejection ports to be formed, thereby functioning as a liquid ejection head. The same applies to Figures 6(a) and (b), and also to Figures 9 and 10 described below, but only one flow path is shown. Furthermore, from Figure 11 onwards, the overall configuration will be shown using the flow path shown in Figure 6(c) as an example.

[0064] FIG. 8 shows the circulation flow rate for each flow path configuration. FIG. 8(a) is a plan view of an individual flow path section in a comparative example without a high-resistance structure, viewed from the direction in which droplets are ejected from the ejection port. FIG. 8(b) is a cross-sectional view of FIG. 8(a). FIG. 8(c) is a graph showing the average circulation flow rate from a simulation when the circulation heater, which is the second energy generating element, is driven once for the plan view of FIG. 8(a) without a high-resistance structure and the present example, FIG. 6(c) with a high-resistance structure. Here, because there is a flow velocity distribution in the cross-sectional direction, the average circulation flow rate, which is the circulation flow rate averaged over the cross-sectional area, is shown. Note that the circulation flow rate is obtained by integrating along the horizontal axis in FIG. 8(c).

[0065] Figure 8(c) shows that in this embodiment with a high-resistance structure, the average circulation flow velocity is higher than in the comparative example, and the circulation flow rate is also higher. Furthermore, in the simulation, the flow path height was 24 μm, the pressure chamber width was 30 μm, the flow path width other than the pressure chamber width was 28 μm, the circulation heater (second energy generating element) had a heater size equivalent to 15 μm x 15 μm, the flow path length was 115 μm, and the viscosity of the circulating liquid was 4 cp. Similarly, with other dimensions and conditions, the circulation flow rate was higher with a high-resistance structure. As described above, it can be seen that the circulation flow rate is improved by providing a high-resistance structure in the center of the flow path between the first energy generating element and the second energy generating element.

[0066] (Driving method of the embodiment: toggle driving) In this embodiment, a selection drive circuit 200 as shown in Fig. 13 is formed on a substrate 18. A voltage source and a controller 110 are provided outside the substrate 18 and connected to the selection drive circuit 200 on the substrate 18. An on-on drive circuit (first switch for switching on and off) 230 is included that turns on and drives either the first energy generating elements (A1 to A16) or the second energy generating elements (B1 to B16) in response to a control signal at each address (N1 to N16 in this embodiment) received from the control data supply circuit 100.

[0067] That is, the control data supply circuit 100 has a switch configured to mutually exclusively switch the first energy generating element and the second energy generating element so that only one of them is in a driveable state. This switch ensures that when the first energy generating element is in a driveable state, the second energy generating element is always in a driveable state, and conversely, when the second energy generating element is in a driveable state, the first energy generating element is always in a driveable state. Here, the control data supply circuit 100 controls the drive pulse for driving the first energy generating element or the second energy generating element and the time (interval) for applying the drive pulse to each element.

[0068] Then, even when the second energy generating element side is selected in the ON-ON drive circuit 230, the second energy generating element is further driven in response to the drive enable / disable signal 300 of the second energy generating element. The drive of the energy generating element is controlled by an on-off drive circuit (second switch for switching on and off) 240. That is, the second energy generating element is further controlled by a switch configured to be switchable between a driveable state and a non-driveable state. Therefore, when the first energy generating element is in a non-driveable state, the second energy generating element is in a driveable state, but is actually driven only when a drive signal (drive enable / disable signal) instructing the second energy generating element to be driven is received. If there is no drive enable / disable signal, the second energy generating element will not be driven even if the second energy generating element side is selected by the on-on drive circuit 230. That is, in this case, neither the first energy generating element nor the second energy generating element will be driven.

[0069] To summarize the above, in this embodiment, the drive circuit for controlling the drive of the first energy generating element and the second energy generating element has a first switch configured to be able to switch the first energy generating element and the second energy generating element exclusively with each other so that only one of them is in a driveable state, and a second switch configured to be able to switch the second energy generating element between a driveable state and an indriveable state, and by using this drive circuit, the first energy generating element and the second energy generating element are configured to be drive-controlled under the following conditions. Condition: When the first energy generating element is driven, the second energy generating element is not driven, and when the first energy generating element is not driven, the second energy generating element is driven when a drive signal instructing the second energy generating element to be driven is received.

[0070] Furthermore, it is preferable that the on-off drive circuit (second switch) is provided closer to the second energy generating element than the on-on drive circuit (first switch) and electrically downstream of the second energy generating element. It is also preferable that a common drive signal is used to drive and control a plurality of second energy generating elements.

[0071] In such control, the controller 110 and the control data supply circuit 100 can be considered as a drive control section for controlling the driving of the first energy generating element and the second energy generating element.

[0072] In addition to the toggle drive described above, drive control may be performed such that the drive of the first energy generating element and the drive of the second energy generating element are controlled separately.

[0073] (Second embodiment) FIG. 9 is a schematic diagram illustrating in detail the vicinity of the ejection ports of a liquid ejection head that ejects liquid such as ink in the second embodiment. FIGS. 9(a) to 9(c) are plan views of the individual flow path portion as viewed from the direction in which droplets are ejected from the ejection ports. FIG. 9(d) is a cross-sectional view common to FIGS. 9(a) to 9(c). In addition to the configuration of this embodiment, it is also possible to place filters on both sides of the individual flow paths or only on the first energy generating element side. In that case, they can be placed in the same positions as in FIGS. 6(b) and 6(c).

[0074] This embodiment differs from the first embodiment in that a narrowing structure 52 that narrows the flow path width is provided between the first energy generating element 14 and the second energy generating element 24. In this embodiment, Fig. 9(a) shows an example in which a narrowing structure 52 is provided in a portion of the flow path between the first energy generating element 14 and the second energy generating element 24. Fig. 9(b) shows a modified example in which a narrowing structure 52 is provided in a longer portion of the flow path between the first energy generating element 14 and the second energy generating element 24. Fig. 9(c) shows a modified example in which a narrowing structure 52 that narrows the flow path width continuously rather than discontinuously is provided. That is, in Fig. 9(b), the flow path width switches discontinuously between the narrow and wide flow path portions, whereas in Fig. 9(c), the flow path width switches continuously. The constriction structure 52 is a type of resistance structure that increases the flow resistance between the first energy-generating element 14 and the second energy-generating element 24.

[0075] An advantage of this configuration is that, as with the first embodiment, it is possible to shorten the flow path while achieving both a high circulation flow rate and refill characteristics during ejection by increasing the flow resistance between the first energy generating element 14 and the second energy generating element 24. Furthermore, to achieve high flow resistance, instead of forming a standalone high resistance structure 51 as in the first embodiment, a narrowing structure 52 is provided that is integrated with the flow path wall that forms the individual flow path, which improves adhesion to the substrate and makes it less likely to peel off.

[0076] Here, the length of the constriction structure 52 in the circulation direction preferably excludes the lengths of the first energy generating element 14 and the second energy generating element 24. This is because a large difference in flow resistance between the left and right sides of the first energy generating element 14 occurs, and the first energy generating element itself is close to or overlaps the flow path wall, which affects discharge. Also, for the second energy generating element 24, if the second energy generating element itself is overlapped by the flow path wall, this affects foaming, and the size of the bubbles in the second energy generating element 24 becomes smaller, resulting in a decrease in the circulation flow rate.

[0077] (Third embodiment) FIG. 10 is a schematic diagram illustrating in detail the vicinity of the ejection ports of a liquid ejection head that ejects liquid such as ink in the third embodiment. FIGS. 10(a) to 10(c) are plan views of the individual flow path portion as viewed from the direction in which droplets are ejected from the ejection ports. FIGS. 10(d) to 10(f) are cross-sectional views of FIGS. 10(a) to 10(c). In addition to the configuration of this embodiment, it is also possible to place filters on both sides of the individual flow paths or only on the first energy generating element side. In that case, they can be placed in the same positions as in FIGS. 6(b) and 6(c).

[0078] This embodiment differs from the first embodiment in that a step structure 53 is provided between the first energy generating element 14 and the second energy generating element 24 to narrow the height of the flow path. In this embodiment, FIG. 10(a) shows an example in which the step structure 53 is provided at the top of a portion of the flow path between the first energy generating element 14 and the second energy generating element 24. FIG. 10(b) shows a modified example in which the step structure 53 is provided at the bottom of a portion of the flow path. FIG. 10(c) shows a modified example in which the step structure 53 is provided at the bottom of a longer portion of the flow path between the first energy generating element 14 and the second energy generating element 24. The step structure 53 is a type of resistance structure that increases the flow resistance between the first energy generating element 14 and the second energy generating element 24.

[0079] Here, the step structure 53 at the upper part of the flow path may be made of the same material as the orifice plate 9 that forms the discharge port. While the step structure 53 is shown as spanning the entire width of the flow path in the figure, it may also be a portion of the width of the flow path. Furthermore, the step structure 53 at the lower part of the flow path may be made of the same material as the orifice plate 9, or may be a partial structure of a circuit or the like formed on the substrate. The lower step structure 53 is also shown as a portion of the width of the flow path, but it may also be a step structure spanning the entire width of the flow path. Here, it is shown as a portion of the width of the flow path in consideration of the flow path walls of the individual flow paths climbing up and down steps and the adhesion due to differences in material between the flow path walls of the individual flow paths and the outermost surface of the substrate. In this disclosure, the direction from the first energy generating element 14 toward the discharge port 11 in the individual flow path 23 is defined as the height direction, and the direction perpendicular to the height direction and the extension direction of the individual flow path 23 is defined as the width direction.

[0080] The advantage of this configuration is that, as in the first embodiment, by increasing the flow resistance between the first energy generating element 14 and the second energy generating element 24, it is possible to shorten the flow path while achieving both a high circulation flow rate and refill characteristics during ejection. Therefore, because step structure 53 is formed on the upper or lower part, adhesion to the substrate is unlikely to be an issue. For example, in the case of upper step structure 53, if it is integrated with orifice plate 9 using the same material, there is no need to consider adhesion to the substrate. In addition, in the case of lower step structure 53, if it is a partial structure formed on the substrate, there is no need to consider adhesion to the substrate either.

[0081] Here, the length of the step structure 53 in the circulation direction preferably excludes the lengths of the first energy generating element 14 and the second energy generating element 24, as described above for the constriction structure 52. Furthermore, in the case of the lower step structure 53, if it is a partial structure such as a circuit formed on the substrate, the first energy generating element 14 and the second energy generating element 24 are also formed in the same manner.

[0082] (Fourth embodiment) Fig. 11 is a schematic diagram illustrating in detail the vicinity of the ejection orifices of a liquid ejection head that ejects liquid such as ink in the third embodiment. Fig. 11(a) is a plan view seen from the direction in which droplets are ejected from the ejection orifices. Figs. 11(b) and (c) are two examples of AB cross-sectional views of Fig. 11(a), which are similar to Figs. 7(b) and (c).

[0083] This embodiment differs from the second embodiment in that three supply opening arrays are provided, resulting in a double array of ejection openings, with each ejection opening array located closer to the central supply opening array. That is, ejection opening arrays are formed on both sides of the direction in which the multiple supply openings are arranged. The ejection opening array is an array of ejection openings 11 included in a unit array in which multiple individual ejection units are lined up. In this embodiment, a first unit array and a second unit array are arranged in parallel. Here, the central opening array shared by the first unit array and the second unit array is referred to as the second opening array in which the second openings are arranged. Furthermore, the end opening arrays of the first unit array and the second unit array are referred to as the first opening array in which the first openings are arranged.

[0084] The advantage of this configuration is that by increasing the number of supply openings by one, from two to three, the number of ejection opening rows can be doubled from one to two. As shown in the figure, it is also possible to arrange the two ejection opening rows with a different pitch. In addition, a configuration is possible in which no wiring area is required between the openings in the central supply opening row, allowing for a high degree of freedom in the size and resolution of the openings in the central supply opening row. This makes it easier to speed up refilling of the nozzles and achieve high productivity.

[0085] In this embodiment, the three supply opening rows are positioned at the same location in the direction between the nozzle rows, but they may be shifted in each row in accordance with the nozzle position and the wiring layout between the openings. This also applies to the following embodiments.

[0086] (Fifth embodiment) 12A and 12B are schematic diagrams illustrating in detail the vicinity of the ejection ports of a liquid ejection head that ejects liquid such as ink in a fourth embodiment. Fig. 12A is a plan view seen from the direction in which droplets are ejected from the ejection ports. Fig. 12B is an AB cross-sectional view of Fig. 12A.

[0087] The difference between this embodiment and the third embodiment is that there is an ejection port row on the side closer to the supply opening rows on both sides, and there is a second energy generating element 24 on the side closer to the central supply opening row, which reverses the direction of the circulating flow.

[0088] The advantage of this configuration is that the ink concentrated near the ejection ports is branched off and discharged to the supply opening arrays on both sides, which reduces the influence of the concentrated ink when it re-flows into the individual flow paths in response to ejection, etc. Also, since the ejection port arrays are arranged apart, the meniscus caused by ejection from each ejection port is reduced. One of the advantages is that interference effects caused by vibrations are suppressed.

[0089] As mentioned at the beginning, the present disclosure aims to provide a liquid ejection head capable of maintaining a desired circulation efficiency and a circulation flow rate while further miniaturizing the head and recording device by shortening the circulation flow path and reducing the substrate size. To this end, a configuration is adopted in which multiple individual ejection units are provided, each having an ejection port, a pressure chamber, a first energy generating element provided in the pressure chamber, an individual flow path communicating with the pressure chamber, and a second energy generating element provided in the individual flow path. In the individual ejection unit, the direction in which the ejection port array is arranged intersects with the extension direction of the individual flow path including the first energy generating element and the second energy generating element, thereby increasing or decreasing the flow resistance or the cross-sectional area of ​​the flow path between the first energy generating element and the second energy generating element. Specifically, instead of lengthening the flow path, the individual flow path is provided with a high-resistance structure, a narrowed structure, or a stepped structure, thereby increasing the flow resistance on one side of the second energy generating element. This makes it possible to provide a liquid ejection head capable of increasing circulation efficiency and ensuring a circulation flow rate without lengthening the circulation flow path.

[0090] [Configuration 1] an individual discharge unit having: a discharge port for discharging liquid; a pressure chamber communicating with the discharge port; a first energy generating element provided in the pressure chamber and generating thermal energy for discharging liquid from the discharge port; an individual flow path communicating with the pressure chamber; and a second energy generating element provided in the individual flow path and generating thermal energy; a common flow path that supplies liquid to the individual flow paths of the plurality of individual discharge units; A liquid ejection head having a plurality of the ejection ports included in a plurality of the individual ejection units form an ejection port array, In the individual flow path of the individual discharge unit, the first energy generating element and the second energy generating element are arranged in a direction intersecting the discharge port array, the individual flow paths extend in a direction intersecting the ejection port array so that both ends of the individual flow paths are positioned on either side of the ejection port array; The individual flow paths are provided with a resistance structure that increases the flow resistance between the first energy generating element and the second energy generating element. A liquid ejection head characterized by: [Configuration 2] When the first energy generating element is driven, the second energy generating element is not driven, When the first energy generating element is not driven, the second energy generating element is driven when a drive signal instructing the second energy generating element to be driven is received. The liquid ejection head according to configuration 1. [Configuration 3] a drive control unit for controlling the driving of the first energy generating element and the second energy generating element; 3. The liquid ejection head according to configuration 2. [Configuration 4] The driving of the first energy generating element and the driving of the second energy generating element are controlled individually. The liquid ejection head according to configuration 1. [Configuration 5] The resistance structure is a pillar structure provided at the center of the individual flow path. 5. The liquid ejection head according to any one of configurations 1 to 4. [Configuration 6] The pillar structure is a cylindrical structure. 6. The liquid ejection head according to configuration 5. [Configuration 7] The resistance structure is a structure in which the cross-sectional area of ​​the individual flow path is narrowed between the first energy generating element and the second energy generating element. 5. The liquid ejection head according to any one of configurations 1 to 4. [Configuration 8] When a direction from the first energy generating element toward the discharge port in the individual flow path is defined as a height direction and a direction perpendicular to the height direction and the extending direction of the individual flow path is defined as a width direction, the resistance structure is a narrowing structure provided in the width direction of the individual flow path, which narrows the flow path width. 8. The liquid ejection head according to configuration 7. [Configuration 9] In the narrowed structure, the flow path width changes continuously between the narrow portion and the wide portion. A liquid ejection head according to configuration 8. [Configuration 10] The resistance structure is a step structure in which the individual flow path narrows in a height direction from the first energy generating element toward the discharge port, when the height direction is defined as the height direction of the individual flow path. 8. The liquid ejection head according to configuration 7. [Configuration 11] The step structure is provided on the ejection port side in the height direction and is made of the same material as the material that forms the ejection port. 11. The liquid ejection head according to configuration 10. [Configuration 12] The step structure is provided on the side of the first energy generating element in the height direction and is configured as a part of a substrate on which the first energy generating element and the second energy generating element are formed. 11. The liquid ejection head according to configuration 10. [Configuration 13] The resistance structure is provided in a region between the first energy generating element and the second energy generating element in the individual flow path. 13. The liquid ejection head according to any one of configurations 7 to 12. [Configuration 14] The step structure is provided in a part of the individual flow path in the width direction. 13. The liquid ejection head according to any one of configurations 10 to 12. [Configuration 15] The individual flow paths are connected to the common flow path at both ends, and filters are disposed at the connections between the individual flow paths and the common flow path at both ends. 13. The liquid ejection head according to any one of configurations 1 to 12. [Configuration 16] The individual flow paths are connected to the common flow path at both ends thereof, and a filter is disposed on one of the both ends of the individual flow paths on the side of the first energy generating element. 13. The liquid ejection head according to any one of configurations 1 to 12. [Configuration 17] The individual flow paths included in the individual discharge units are connected to the common flow path via openings. 13. The liquid ejection head according to any one of configurations 1 to 12. [Configuration 18] One end and the other end of the individual flow path are connected to the common flow path via a first opening and a second opening, respectively. The first openings and the second openings included in the individual discharge units are connected to a flow path, and are arranged along a discharge port array, which is a row of the discharge ports included in the individual discharge units. 13. The liquid ejection head according to any one of configurations 1 to 12. [Configuration 19] one end and the other end of the individual flow path are connected to the common flow path via a first opening and a second opening, respectively; a plurality of the individual discharge units are arranged in a direction perpendicular to the extension direction of the individual flow paths to form a unit row, and a first unit row and a second unit row are arranged in parallel, The individual flow paths included in the first unit array and the individual flow paths included in the second unit array share the second opening, and the shared second openings are arranged in a direction perpendicular to the extension direction of the individual flow paths to form a second opening row. The first openings included in the first unit row and the first openings included in the second unit row are respectively arranged in a direction perpendicular to the extension direction of the individual flow paths to form a plurality of first opening rows. 13. The liquid ejection head according to any one of configurations 1 to 12. [Configuration 20] In each of the plurality of individual flow paths, the first energy generating element is disposed on a side closer to the second opening. 19. A liquid ejection head according to claim 19. [Configuration 21] In each of the plurality of individual flow paths, the second energy generating element is disposed on a side closer to the second opening. 19. A liquid ejection head according to claim 19. [Configuration 22] The second energy generating element performs a circulation drive to circulate the liquid in the individual flow paths, and the first energy generating element performs a discharge drive to discharge the liquid from the discharge port. 13. The liquid ejection head according to any one of configurations 1 to 12. [Configuration 23] The circulation drive is a drive with weaker energy than the ejection drive. 23. A liquid ejection head according to claim 22. [Explanation of symbols]

[0091] 11: Discharge port, 12: Pressure chamber, 14: First energy generating element, 24: Second energy generating element

Claims

1. an individual discharge unit including: a discharge port for discharging liquid; a pressure chamber communicating with the discharge port; a first energy generating element provided in the pressure chamber and generating thermal energy for discharging liquid from the discharge port; an individual flow path communicating with the pressure chamber; and a second energy generating element provided in the individual flow path and generating thermal energy; a common flow path that supplies liquid to the individual flow paths of the plurality of individual discharge units; A liquid ejection head having a plurality of the ejection ports included in a plurality of the individual ejection units form an ejection port array, In the individual flow path of the individual discharge unit, the first energy generating element and the second energy generating element are arranged in a direction intersecting the discharge port array, the individual flow paths extend in a direction intersecting the ejection port array so that both ends of the individual flow paths are positioned on either side of the ejection port array; The individual flow paths are provided with a resistance structure that increases the flow resistance between the first energy generating element and the second energy generating element. A liquid ejection head characterized by:

2. When the first energy generating element is driven, the second energy generating element is not driven, When the first energy generating element is not driven, the second energy generating element is driven when a drive signal instructing the second energy generating element to be driven is received. The liquid ejection head according to claim 1 .

3. a drive control unit for controlling the driving of the first energy generating element and the second energy generating element; The liquid ejection head according to claim 2 .

4. The driving of the first energy generating element and the driving of the second energy generating element are controlled individually. The liquid ejection head according to claim 1 .

5. The resistance structure is a pillar structure provided at the center of the individual flow path. The liquid ejection head according to claim 1 .

6. The pillar structure is a cylindrical structure. The liquid ejection head according to claim 5 .

7. The resistance structure is a structure in which the cross-sectional area of ​​the individual flow path is narrowed between the first energy generating element and the second energy generating element. The liquid ejection head according to claim 1 .

8. When a direction from the first energy generating element toward the discharge port in the individual flow path is defined as a height direction, and a direction perpendicular to the height direction and the extending direction of the individual flow path is defined as a width direction, the resistance structure is a narrowing structure provided in the width direction of the individual flow path, which narrows the flow path width. The liquid ejection head according to claim 7 .

9. In the narrowed structure, the flow path width changes continuously between the narrow portion and the wide portion. The liquid ejection head according to claim 8 .

10. The resistance structure is a step structure in which the individual flow path narrows in a height direction from the first energy generating element toward the ejection port, when the height direction is defined as the height direction of the individual flow path. The liquid ejection head according to claim 7 .

11. The step structure is provided on the ejection port side in the height direction and is made of the same material as the material that forms the ejection port. The liquid ejection head according to claim 10.

12. The step structure is provided on the side of the first energy generating element in the height direction and is configured as a part of a substrate on which the first energy generating element and the second energy generating element are formed. The liquid ejection head according to claim 10.

13. The resistance structure is provided in a region between the first energy generating element and the second energy generating element in the individual flow path. The liquid ejection head according to any one of claims 7 to 12.

14. The step structure is provided in a part of the individual flow path in the width direction. The liquid ejection head according to any one of claims 10 to 12.

15. The individual flow paths are connected to the common flow path at both ends, and filters are disposed at the connections between the individual flow paths and the common flow path at both ends. The liquid ejection head according to claim 1 .

16. The individual flow paths are connected to the common flow path at both ends thereof, and a filter is disposed on one of the ends of the individual flow paths on the side of the first energy generating element. The liquid ejection head according to claim 1 .

17. The individual flow paths included in the individual discharge units are connected to the common flow path via openings. The liquid ejection head according to claim 1 .

18. One end and the other end of the individual flow path are connected to the common flow path via a first opening and a second opening, respectively, and the first openings and the second openings included in the individual discharge units are each arranged along a discharge port array, which is a row of the discharge ports included in the individual discharge units. The liquid ejection head according to claim 1 .

19. one end and the other end of the individual flow path are connected to the common flow path via a first opening and a second opening, respectively; a plurality of the individual discharge units are arranged in a direction perpendicular to the extending direction of the individual flow paths to form a unit row, and a first unit row and a second unit row are arranged in parallel, The individual flow paths included in the first unit array and the individual flow paths included in the second unit array share the second opening, and the shared second openings are arranged in a direction perpendicular to the extension direction of the individual flow paths to form a second opening row. The first opening included in the first unit row and the second opening included in the second unit row The first openings are arranged in a direction perpendicular to the extending direction of the individual flow paths to form a plurality of first opening rows. The liquid ejection head according to claim 1 .

20. In each of the plurality of individual flow paths, the first energy generating element is disposed on a side closer to the second opening.

20. The liquid ejection head according to claim 19.

21. In each of the plurality of individual flow paths, the second energy generating element is disposed on a side closer to the second opening.

20. The liquid ejection head according to claim 19.

22. The second energy generating element performs a circulation drive to circulate the liquid in the individual flow paths, and the first energy generating element performs a discharge drive to discharge the liquid from the discharge port. The liquid ejection head according to claim 1 .

23. The circulation drive is a drive with weaker energy than the ejection drive.

23. The liquid ejection head according to claim 22.

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