Liquid ejecting head

Abstract

A liquid ejection head includes: a single-use ejection unit including an ejection port, a pressure chamber, a first energy generating element provided in the pressure chamber and generating thermal energy, and a second energy generating element provided in a single-use flow path and generating thermal energy; and a common flow path that supplies the liquid to the single-use flow path, in which the direction in which the ejection ports are arranged perpendicularly intersects the direction in which the single-use flow path extends, and in which a liquid ejection head provided with a structure that increases the flow resistance between the first energy generation element and the second energy generation element is used.

Description

Technical Field

[0001] This disclosure relates to liquid injection heads. Background Technology

[0002] To remove air bubbles from the flow path of the liquid ejector head (hereinafter also referred to as "head") and suppress the increase in ink viscosity near the ejector nozzle, a circulating liquid ejector device for circulating ink is known. As a method for circulating ink, a pressure differential scheme (hereinafter also referred to as "pressure differential scheme") is well known. In this scheme, the pressure on the side supplying ink to the ejector nozzle (inlet side) is increased using a pressure regulating mechanism or the like, compared to the side where ink is recovered (outlet side), thereby causing ink to flow from the inlet side to the outlet side. In this case, to circulate the ink, it is necessary to return the ink that has already flowed to the outlet side to the inlet side, and a pump is required as a mechanism for this. There is also a configuration in which, in the case where liquid is circulated between the liquid ejector head and the recording device body by installing a pump outside the liquid ejector head of the recording device body, liquid is circulated inside the liquid ejector head by installing a pump inside the liquid ejector head. However, this pressure differential circulation method requires a pressure regulating mechanism and a mechanism such as a pump, and the size of the recording device body and the head is easily increased.

[0003] Therefore, ink circulation methods other than differential pressure schemes have been studied. Specifically, a mechanism is known in which ink is circulated in the circulation path by setting up a circulation path connected to the ejector, arranging an energy generating element (hereinafter referred to as a "flow energy generating element") different from the energy generating element used for ejecting ink (hereinafter also referred to as a "jet energy generating element") in the circulation path, and driving the flow energy generating element to circulate ink in the circulation path.

[0004] Japanese Patent Application Publication No. 2020-104312 discloses a structure in which a circulating flow path is provided that extends to intersect with a column of multiple jet nozzles, and a flow energy generating element is included in the circulating path. Summary of the Invention

[0005] This disclosure provides a liquid injection head, comprising:

[0006] A single-purpose injection unit includes a jet nozzle for injecting liquid, a pressure chamber communicating with the jet nozzle, a first energy generating element disposed in the pressure chamber and generating heat energy for injecting liquid from the jet nozzle, a single-purpose flow path communicating with the pressure chamber, and a second energy generating element disposed in the single-purpose flow path and generating heat energy; and

[0007] A shared flow path is configured to supply liquid to the dedicated flow paths of multiple dedicated injection units, wherein,

[0008] Multiple injection ports included in multiple single-use injection units form an injection port array.

[0009] The first energy generating element and the second energy generating element are arranged in the single-purpose flow path of the single-purpose injection unit along a direction that intersects with the injection nozzle array.

[0010] The single-use flow path extends in a direction intersecting with the nozzle array, such that the two ends of the single-use flow path are positioned such that the nozzle array is located between the two ends, and

[0011] The single-flow path is equipped with a resistance structure that increases the flow resistance between the first energy generating element and the second energy generating element.

[0012] The features of this disclosure will become apparent from the following description of embodiments with reference to the accompanying drawings. The embodiments are described below by way of example. Attached Figure Description

[0013] Figure 1A and Figure 1B This is an overall view of the device using a liquid injection head.

[0014] Figures 2A to 2D This is an overall view of the liquid jet head and an overall view of the liquid jet chip.

[0015] Figures 3A to 3D This is a schematic diagram of the area near the nozzle of a liquid injection head.

[0016] Figures 4A to 4C This is a schematic diagram of the area near the nozzle of a liquid injection head.

[0017] Figures 5A to 5D This is a schematic diagram of the area near the nozzle of a liquid injection head.

[0018] Figures 6A to 6F This is a schematic diagram of the vicinity of the liquid injection head according to the first embodiment.

[0019] Figures 7A to 7C This is an overall schematic diagram of the vicinity of the liquid injection head according to the first embodiment.

[0020] Figures 8A to 8C These are circulating flow diagrams in some examples of the first embodiment.

[0021] Figures 9A to 9D This is a schematic diagram of the area near the nozzle of the liquid injection head according to the second embodiment.

[0022] Figures 10A to 10F This is a schematic diagram of the area near the nozzle of the liquid injection head according to the third embodiment.

[0023] Figures 11A to 11C This is a schematic diagram of the area near the nozzle of the liquid injection head according to the fourth embodiment.

[0024] Figure 12A and Figure 12B This is a schematic diagram of the area near the nozzle of the liquid injection head according to the fifth embodiment.

[0025] Figure 13 This is a circuit construction diagram based on the first embodiment. Detailed Implementation

[0026] Preferred embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. It should be noted that the following embodiments do not limit the scope of the present disclosure, and not all combinations of features described in these embodiments are essential to the technical solutions of the present disclosure. Note that identical components will be denoted by the same reference numerals. In the following description, the basic structure of the present disclosure will be described first, followed by the characteristic portions of the present disclosure.

[0027] According to the inventors' research, in the prior art, in order to optimize the circulation efficiency of the flowing energy generating element to maximize the circulation flow rate, it is necessary to lengthen the circulation path, which increases the size of the substrate including the energy generating element, thereby increasing the size of the head and recording device. On the other hand, if the circulation path is simply shortened, the circulation efficiency of the flowing energy generating element decreases, which leads to a reduction in circulation flow rate. Therefore, there is a need for a liquid jet head that can exhibit the desired circulation efficiency and maintain the circulation flow rate even with a shortened circulation path and a smaller substrate size.

[0028] Liquid injection device

[0029] First, the general structure of the liquid injection device 50 according to this embodiment will be described. Figure 1A and Figure 1B This is an enlarged view of the liquid injection head 1 and its vicinity in the liquid injection device 50, wherein, Figure 1A and Figure 1B This is a schematic perspective view of a liquid injection device employing a liquid injection head. Figure 1A and Figure 1BThe liquid ejection device 50 shown is a type of liquid ejection device (serial liquid ejection device) in which an image is formed by ejecting liquid onto the recording medium P through a liquid ejection head that performs scanning in a direction intersecting the transport direction of the recording medium P. This disclosure is applicable not only to serial liquid ejection devices but also to page-width liquid ejection devices that record images by using a linear head (page-width head) that extends along the page width direction of the recording medium to eject liquid onto the recording medium being transported in the transport direction. Note that the liquid ejection head according to this embodiment can eject four types of ink: black (K), cyan (C), magenta (M), and yellow (Y), and can use these inks to record full-color images. The inks that can be ejected from the liquid ejection head are not limited to the above four types. This disclosure can also be applied to liquid ejection heads that eject other types of ink. In other words, the type and quantity of ink ejected from the liquid ejection head are not limited.

[0030] In the serial liquid jetting apparatus 50, the liquid jetting head 1 is mounted on a carriage 60. The carriage 60 reciprocates along a guide shaft 62 in the main scanning direction (X direction). The recording medium is transported in the sub-scanning direction (Y direction) intersecting (perpendicularly in this example) with the main scanning direction via transport rollers (transport mechanisms) 55, 56, 57, and 58. Note that in each of the figures referred to herein, the Z direction represents the vertical direction and intersects (perpendicularly in this example) the XY plane defined by the X and Y directions.

[0031] Figure 1A The diagram shows a structure in which the main ink tank 2, serving as a liquid storage unit, is located outside the liquid ejector head. Driven by an external pump 28, the liquid (ink) stored in the ink tank 2 is supplied to the auxiliary ink tank 54 on the side of the liquid ejector head 1 via an ink supply pipe (liquid communication path) 59, etc. On the other hand, Figure 1B The diagram shows a configuration including an ink tank 54 directly above the liquid ejector head 1 (excluding the main ink tank 2, which serves as a liquid storage unit, located outside the liquid ejector head). In this case, the liquid ejector head 1 can be integrally mounted with the ink tank 54, or configured to be detachable / installable relative to the carriage 60; or the liquid ejector head 1 can be integrally mounted with the carriage 60, while only the ink tank 54 is configured to be detachable / installable. The following will use... Figure 1A The construction in the example is described as a representative example.

[0032] Liquid injection head 1 is configured to include a single-use injection unit, which will be described later (see [link to documentation]). Figures 2A to 2DAlthough the specific construction will be described later, the single-use injection unit is provided with an injection port for injecting liquid, a pressure chamber communicating with the injection port, a first energy generating element (ejection energy generating element) disposed in the pressure chamber and generating energy for injecting liquid from the injection port, a single-use flow path communicating with the pressure chamber, and a second energy generating element (flow energy generating element) disposed in the single-use flow path. The liquid injection head 1 includes a plurality of single-use injection units and includes a supply flow path for supplying liquid to the single-use flow path in the single-use injection unit.

[0033] When using a liquid ejector head, the liquid ejection can become unstable due to the evaporation of volatile components (such as moisture) from the ejector nozzle and the accompanying concentration of solid contents near the nozzle. Various arrangements have been made to prevent this. For example, a cover member (not shown) can be provided in the liquid ejector device at a position spaced apart from the recording medium transport path in the X direction to cover the surface of the ejector nozzle in which the ejector nozzle is formed. The cover member is used to cover the surface of the ejector nozzle of the liquid ejector head when no recording operation is performed, to prevent the nozzle from drying out, and to protect the nozzle. In addition, an ink suction mechanism (not shown) can be provided, in which case the cover member is used to perform an ink suction operation to draw ink from the ejector nozzle. By performing the ink suction operation, the ink near the nozzle can be refreshed and the level of image quality obtained can be maintained. Furthermore, methods for performing a type of ejection called pre-ejection (pre-discharge) to discard concentrated ink when no recording operation is performed, and for pre-ejecting ink (paper surface pre-ejection / intra-page pre-ejection) of ink in a position and amount that is not noticeable in terms of image quality on the recording medium even during recording operation, are also known. While these methods greatly improve image quality, they waste some ink to refresh the nozzle, so the amount of ink to be wasted needs to be minimized.

[0034] To address this issue, by incorporating a second energy-generating element (flow energy-generating element) into the single-use flow path and circulating the ink within it, the amount of ink to be discarded can be reduced while simultaneously suppressing nozzle drying and ink concentration near the nozzle. More specifically, the number of pre-jet, suction, and recovery cycles can be minimized. Furthermore, minimizing the number of pre-jet cycles, etc., leads to increased throughput and production volume.

[0035] It is not necessary to install a second energy generating element (flow energy generating element) in all single-use injection units of the liquid jet head. Compared to the case where no second energy generating element is installed in any single-use injection unit, the above-mentioned effect can be achieved by installing a second energy generating element in some single-use injection units.

[0036] in addition, Figure 1AThe liquid jet head shown can be configured such that all portions corresponding to the four inks include a second energy generating element, or it can be configured such that only the portion corresponding to one ink includes a second energy generating element. In other words, the liquid jet head can be configured to circulate only at least one ink instead of all four inks.

[0037] Basic structure of liquid injection head

[0038] Figure 2A This is an exploded perspective view of the liquid injection head according to this embodiment. Figures 2A to 2D As shown, the liquid ejection head is constructed to include: a secondary ink reservoir 54 for temporarily storing ink in the head; and a liquid ejection chip 3 for ejecting ink supplied from the secondary ink reservoir 54 onto the recording medium P. According to this embodiment, the liquid ejection head is fixedly supported on the carriage by a positioning mechanism and electrical contacts provided in the carriage of the liquid ejection device (not shown). The liquid ejection head moves along the carriage... Figure 1A and Figure 1B As shown, ink is ejected while the main scanning direction (X direction) is moved, thereby performing recording on the recording medium P.

[0039] An external pump 28 connected to the ink tank 2, which serves as the ink supply source, is equipped with an ink supply pipe 59 (see...). Figure 1A A liquid connector (not shown) is located at the distal end of the ink supply tube. When the liquid ejector head 1 is mounted on the liquid ejection device 50, the liquid connector located at the distal end of the ink supply tube 59 is liquid-tightly connected to a liquid connector insertion port located in the head housing of the liquid ejector head 1 and serving as a liquid inlet. In this way, an ink supply path is formed from the ink tank 2 to the liquid ejector head 1 via the external pump 28. Since four types of ink are used in this embodiment, four sets are provided corresponding to the ink, each set including the ink tank 2, the external pump 28, the ink supply tube 59, and the auxiliary ink tank 54, and four ink supply paths are independently formed corresponding to the ink. In this way, the liquid ejection device according to this embodiment includes an ink supply system to which ink is supplied from the ink tank 2 located outside the liquid ejector head 1. Note that the liquid ejection device according to this embodiment does not include an ink recovery system that recovers ink from inside the liquid ejector head back to the ink tank. Therefore, although the liquid ejector head is provided with a liquid connector insertion port for establishing a connection with the ink supply tube of the ink tank, the liquid ejector head is not provided with a liquid connector insertion port for establishing a connection with the tube that recycles ink from the liquid ejector head into the ink tank. Note that a liquid connector insertion port is provided for each type of ink.

[0040] Figure 2B , Figure 2C and Figure 2D This is an overall view of the liquid jetting chip that makes up the liquid jetting head. Figure 2BThe construction of a chip for four colors is shown. Figure 2C The construction of a chip for two colors is shown, and Figure 2D The construction of a chip for one color is shown. Each liquid jet chip is provided with a jet nozzle and pads for electrical mounting. Figure 2A It shows Figure 2B The chip structure.

[0041] Figure 2B A first embodiment of a chip configured for four colors is shown. These four colors are, for example, black, cyan, magenta, and yellow, and each color constitutes a column arranged in the Y direction. Adjacent nozzles in each column are arranged offset in the X direction and are arranged at equal intervals in the Y direction. Here, the nozzles in each column can be arranged in one column in the Y direction without any offset in the X direction. Alternatively, nozzles for black only can be arranged in two columns, providing a total of five columns for the four colors.

[0042] Figure 2C A second embodiment is shown, configured for one chip for two colors and using two chips. When the two chips are mounted in a liquid spray head, they can be mounted in one liquid spray head; or two liquid spray heads can be prepared, each including one mounted chip.

[0043] Figure 2D A third embodiment is shown, constructed as a single chip for one color and using four chips. Similar to... Figure 2C Four chips can be installed in one liquid jet head; or four liquid jet heads can be prepared, each containing one installed chip.

[0044] In addition, in such Figure 2C and Figure 2D When multiple chips are prepared in a segmented manner as shown, not all chips need to have the same length. Furthermore, various other combinations of the number of colors can exist for the chips, and this also applies when the total number of colors is greater than four.

[0045] Components of the loop unit

[0046] linear

[0047] Figures 3A to 3D This is a schematic diagram illustrating the area near the nozzle of a linear liquid jet head. In this specification, "linear" means that the single-purpose flow path arranging the first energy generating element (jet energy generating element) and the second energy generating element (flow energy generating element) has a linear shape, which is along the direction intersecting the jet nozzle array. Figures 3A to 3DThe first energy generating element and the second energy generating element are arranged in a direction that intersects with the jet nozzle array in the single-use flow path of the single-use jet unit. In other words, the first energy generating element and the second energy generating element are arranged in a direction that intersects with the jet nozzle array in the single-use flow path of the single-use jet unit.

[0048] Figure 3A This is a plan view taken from the direction in which the droplets are ejected from the nozzle. Figure 3B It is along Figure 3A The sectional view of A-A' in the diagram. Figure 3C It is along Figure 3A Another sectional view of A-A' in the diagram. Figure 3D This is a diagram used to illustrate the flow of ink when the first energy-generating element is driven.

[0049] exist Figures 3A to 3C In the process, a pressure chamber 12, separated by a partition wall 21 and corresponding to the jet nozzle 11, and a single-purpose flow path 23 for allowing ink to flow through the pressure chamber 12 are formed between the substrate 18 and the perforated plate 19. An ink meniscus exists at the jet nozzle 11, and a jet nozzle interface is formed as the interface between ink and the atmosphere.

[0050] The substrate 18 includes a first energy generating element 14 that generates energy for ejecting ink inside the pressure chamber. In this example, a thermoelectric conversion element is used. The first energy generating element 14 is located closer to the second supply port 32, along with the ejection port 11 and the pressure chamber 12, than to the first supply port 22. Ink can be ejected from the ejection port 11 by heating the first energy generating element 14 and causing the ink inside the pressure chamber 12 to bubble.

[0051] Additionally, substrate 18 includes a second energy generating element 24, which generates energy to induce a circulating flow 27 (indicated by the arrow) in the ink within the single-use flow path. In this example, an electrothermal conversion element is used. Therefore, the second energy generating element 24 will also be referred to as a circulating heater 24.

[0052] Furthermore, the substrate 18 is provided with an opening for supplying liquid from a common flow path to a single-use flow path. The opening can be, for example... Figure 3A The multiple openings shown (single supply ports) can also be a single large opening in the supply slot. The second energy generating element 24 is closer to the first supply port 22 than the second supply port 32.

[0053] The single-use flow path 23 extends along a second direction (perpendicularly in this example) that intersects the column direction (first direction) of the nozzle arrangement. The single-use flow path 23 includes a pressure chamber 12. Figure 3B The inlet (upstream) side of the flow path 13, which is connected to the end of the pressure chamber 12, and the inlet (upstream) side, are connected to the flow path 13. Figure 3BThe outlet (downstream) side flow path is connected to the other end of the pressure chamber 12. The single-use flow path 23 is connected to the first supply port 22 and the second supply port 32 penetrating the substrate 18 at one end on the upstream side and the other end on the downstream side. Therefore, the connecting flow path 13 is located closer to the second energy generating element compared to the jet nozzle array. The two ends of the single-use flow path 23 are located on opposite sides, with the jet nozzle array positioned between them. Liquid is supplied from the common flow path 38 to the first supply port 22 and the second supply port 32.

[0054] The ink flow in a single flow path is roughly divided into (1) a first ink flow that drives the first energy generating element 14 and performs supplementary ink flow after ejection, and (2) a second ink flow that drives the second energy generating element 24 to form a circulating flow.

[0055] When the first energy generating element 14 is driven and liquid is ejected from the injection port 11, such as Figure 3D As shown, ink accompanying the jetting is supplied from the first supply port 22 and the second supply port 32, and the ink flows into the pressure chamber from both supply ports.

[0056] When the second energy generating element 24 is driven to form a circulating flow, ink flows into the single-use flow path 23 through the first supply port 22 located on the connecting flow path side, and flows outward through the second supply port 32 not located on the connecting flow path side. In this example, a circulating flow 27, as indicated by the arrow, is formed in the single-use flow path 23 by causing the ink flowing out of the second supply port 32 to return to the first supply port 22 and circulate the ink. Note that in Figure 3B The diagram illustrates a configuration where a first supply port 22 and a second supply port 32 are shared within the chip. Additionally, in... Figure 3C The diagram shows the configuration of the first supply port 22 and the second supply port 32 connected to a single flow path and shared outside the recording head; any of these configurations can be used.

[0057] Pump principle

[0058] Figures 4A to 4C This diagram illustrates the principle of generating an ink circulation flow when each of the second energy generating elements (circulating heaters) 24, which are used as electrothermal conversion elements, is used. Figure 4A , Figure 4B and Figure 4C It is similar to Figure 3B The cross-sectional views show the generation / growth process, contraction process, and defoaming process of bubbles B generated by the film boiling of ink heated by the circulating heater 24. Figure 4A In this configuration, the circulating heater 24 is closer to the first supply port 22 than the second supply port 32. Therefore, the flow resistance R1 between the circulating heater 24 and the first supply port 22 is less than the flow resistance R2 between the circulating heater 24 and the second supply port 32. Figure 4A In this circuit, the equivalent circuits representing such flow resistances R1 and R2 as resistors are combined. Due to the difference between the flow resistances R1 and R2, such as Figure 4A As shown, bubbles B generated due to ink film boiling grow on the first supply port 22 side with low flow resistance R1. Therefore, within each single-use flow path 23, the ink flow Fa toward the first supply port 22 becomes greater than the ink flow Fb toward the outflow flow path 15.

[0059] Figure 4B This is an illustration of the ink flow during the contraction process of bubble B. During the contraction of bubble B, ink flows in to compensate for the volume corresponding to the amount of contraction. At this time, as shown... Figure 4B As shown, the ink flow Fc flowing in from the first supply port 22 located on the side of low flow resistance R1 is greater than the ink flow Fd flowing in from the second supply port 32 located on the side of high flow resistance R2. Furthermore, the defoaming position of bubble B shifts from the portion above the circulating heater 24 towards the side closer to the second supply port 32.

[0060] Figure 4C This is an explanatory diagram showing the process after bubble B defoams. Because in Figure 4B The relationship Fc>Fd generated in the process causes an ink circulation flow F from the first supply port 22 toward the second supply port 32.

[0061] The magnitude of this circulating flow F is affected by the ratio of flow resistances R1 and R2 and the size of bubble B. Specifically, for example, assuming a circulating heater 24 as an electrothermal conversion element is used as a second energy generating element 24, each second energy generating element 24 is preferably closer to one of the two ends of each single-use flow path 23 than the first energy generating element. More specifically, the flow resistance ratio R1 / R2 is preferably set in the range of 0.05 to 0.40. By setting the flow resistance ratio R1 / R2 within this range, the circulating flow F can be maximized. It is important to increase the circulating flow F. Figure 4A and Figure 4B The ink flow Fa towards the first supply port 22 is shown, and the ink flow Fc flowing in from the first supply port 22 is increased. Therefore, it is effective to reduce the flow resistance R1. In addition, it is important to minimize the ink flow Fb towards the outflow path 15 and reduce the ink flow Fd flowing in from the second supply port 32. Therefore, it is effective to increase the flow resistance R2. As mentioned above, 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. In addition, since the bubbles B with large size (i.e., large bubble volume) cause the volume of fluid removed from each single-use flow path 23 to increase, the circulating flow F increases.

[0062] Examples of ways to increase bubble volume include:

[0063] -Increase the size of the circulating heater 24;

[0064] -Increase the width or height inside the flow path 13 to reduce flow resistance;

[0065] - Reduce ink viscosity;

[0066] -Increase head temperature;

[0067] - Doubles the driving pulse.

[0068] A portion of the ink circulation flow F enters the ejector 11 to deliver concentrated ink from the ejector 11 to the second supply port 32 side, while fresh ink flows into the ejector 11 from the first supply port 22 side through the connecting flow path 13. By making it difficult for concentrated ink to remain in the ejector 11, the initial ink ejection state can be maintained while suppressing the influence of concentrated ink.

[0069] The circulating flow F is a transitional flow that occurs during the growth and contraction processes associated with the generation of bubbles B. Therefore, after the bubbles B defoam, the inertial flow weakens over time and eventually stops after a specific time period. Thus, to consistently generate the circulating flow F for a specific time period, it is necessary to repeatedly drive the heating element of the circulating heater 24. The driving cycle of the circulating heater 24 can be any cycle, as long as it can discharge the concentrated ink within the ejector nozzle 11, and there are no particular limitations. However, since the flow is a transitional flow that occurs during the growth and contraction processes associated with the generation of bubbles B, a cycle of 10 μs (which is the defoaming time from the start of bubble generation) is less effective when driven at a driving frequency as high as 100 kHz. Therefore, it is preferable to drive the circulating heater 24, for example, at a cycle of 100 Hz to approximately tens of kHz, and the higher the driving frequency, the better the circulating flow F can be maintained, and the better the effect of discharging the concentrated ink. However, on the other hand, it is necessary to consider the increase in ink temperature caused by the heat generated accompanying the driving of the circulating heater 24. Therefore, it is necessary to appropriately set the number of times the circulating heater 24 is driven.

[0070] It should be noted that it is conceivable that the second energy-generating element responsible for the cycle has a lower driving energy than the typical driving energy used to perform the jet drive. In other words, the cycle drive of the second energy-generating element can be a drive with less energy than the jet drive of the first energy-generating element. Even when the driving energy of the second energy-generating element is reduced, it can be adjusted accordingly by adjusting the size and aspect ratio of the energy-generating element.

[0071] Recycle Concentration

[0072] Figures 5A to 5DThis diagram illustrates how the ink circulation flow generated by the second energy-generating element eliminates concentration. It shows a linear configuration that separates the inlet and outlet of the circulation flow in each single-use flow path, with the concentrated portion of the ink indicated by darker colors, and the concentration level represented by the depth of the color.

[0073] exist Figures 5A to 5D middle, Figure 5A The image shows a temporary pause. During the pause, volatile components evaporate from the nozzle, and ink concentration progresses near the nozzle. Figure 5B The diagram illustrates the state achieved by subsequently inducing a circulating flow via a second energy-generating element. Concentration near the nozzle is eliminated through the circulating flow. The concentrated ink near the nozzle is discharged from the outlet, and concentration is eliminated throughout the entire single-use flow path. Figure 5C The diagram illustrates the state achieved through a subsequent further temporary pause. Similar to... Figure 5A The ink concentration then proceeded again near the nozzle. Figure 5D The diagram shows the state immediately following the further induction of the circulating flow by the second energy-generating element. Similar to... Figure 5B The concentration near the nozzle is eliminated again, and concentration is eliminated in all single-use flow paths. As described above, in the linear flow path with separate inlet and outlet, the concentration state is reset each time the temporary pause and cycle operation is repeated.

[0074] As described above, in a linear flow path where the inlet and outlet of the circulating flow are separated, the concentration state can be reset throughout the entire flow path for each cycle, and therefore, the effects of concentration are less likely to occur continuously and stably through the cycle. Thus, there are structural features that prevent ink concentration from reducing jetting stability.

[0075] ink

[0076] As described above, by inducing ink circulation in a single-use flow path using a second energy-generating element, the effects of concentrated ink with increased viscosity due to evaporation at the nozzle can be suppressed. In other words, the ink ejection state can be satisfactorily maintained, thereby further reducing effects such as variations in ejection speed, and ejection can easily become stable.

[0077] On the other hand, depending on the application of the liquid jet head and the liquid jetting device equipped with the liquid jet head, it is assumed that inks of different types of pigments, different solid content contents, etc., are used. In other words, as a performance feature of the liquid jet head, it is preferable to be able to maintain a high level of jetting stability, regardless of the type of ink used. For example, it is conceivable that inks with reduced water content are used in response to problems caused by water in the ink (such as curling (warping) or wrinkling (wavy wrinkles) of ordinary paper). Since the concentration of solid content contents (such as organic solvents, pigments, resins) other than water is high in inks with reduced water content, the viscosity is prone to increase sharply as the water evaporates, which easily leads to a decrease in ink jetting stability. The method of generating a circulating flow inside the pressure chamber, as described in this disclosure, is very effective for such inks because it can suppress the increase in ink viscosity. Typically, the solid content content in inks containing a large amount of solid content is 10 wt%. In other words, this disclosure is preferably applied to inks with a solid content content of at least 10 wt% (mass percentage).

[0078] Furthermore, regarding the operating temperature of the head, it can be used at a specific temperature by arranging heaters throughout the chip and controlling the heaters. Since ink viscosity varies with temperature, the ink viscosity at the head operating temperature affects jetting stability.

[0079] When a circulating flow is formed via a second energy-generating element, the instantaneous flow velocity can range from tens of mm / s to 1000 mm / s. The average flow velocity over a time span of several hundred microseconds depends on the driving frequency of the circulating heater. This is because, in the case of a circulating heater, the circulating flow is a transitional flow that decays over time and stops after a specific time period. When the second energy-generating element is driven at a frequency (ejection frequency) similar to that of the first energy-generating element (approximately 10 kHz to 20 kHz), the average flow velocity can range from a few mm / s to 100 mm / s.

[0080] When using inks with high pigment concentrations (e.g., ink concentration resulting in a viscosity of at least 3 cp and no more than 6 cp at the head operating temperature), the increase in ink viscosity tends to proceed at the nozzle, depending on the non-jetting time (pause time). Therefore, the jetting speed is prone to change, which can easily lead to reduced jetting stability. Thus, ink circulation needs to be performed with short pause times, and concentration needs to be eliminated by either constant ink circulation or frequent transitional ink circulation. When using a circulating heater as a secondary energy-generating element, transitional ink circulation is achieved, thus frequent circulation operations can help eliminate concentration at the nozzle.

[0081] On the other hand, although the ejection rate changes depending on the non-ejection time (pause time) when using ink with low pigment concentration (e.g., ink concentration resulting in a viscosity of at least 1 cp and no more than 2 cp at the head operating temperature), its effect is relatively small compared to that of high-concentration ink. Conversely, with long pause times, for example, depending on the non-printing drive time (stop time), the increase in ink viscosity progresses at the ejection nozzle. Therefore, when resuming operation after a period of inactivity, recovery processes involving ink waste need to be performed, such as suction operations, wiping operations, and pre-ejection based on these operations. When using a circulating heater as a second energy-generating element, forming a circulating flow as a recovery operation helps eliminate concentration at the ejection nozzle without generating ink waste. Depending on the stop time, ink waste can also be prevented by a recovery process that only includes a circulating operation. Alternatively, a recovery process that minimizes ink waste can be performed by partially combining a suction operation (different from eliminating concentration) for removing air bubbles inside the head while performing a circulating operation for recovery.

[0082] Regardless of whether the ink concentration is high or low, it is desirable to return the ink to its initial fresh state as much as possible in order to suppress the effects of concentrated ink. Therefore, even when using a circulating heater as a secondary energy generation element, the smaller the effect of recirculation and concentration, the better the circulation effect can be obtained. In other words, this is preferably achieved in a linear configuration.

[0083] First Embodiment

[0084] Figures 6A to 6F and Figures 7A to 7C This is a schematic diagram showing the vicinity of the nozzle of a liquid jetting head that sprays liquid (such as ink) according to the first embodiment. Figures 6A to 6C It is a plan view of each single-use flow path as seen from the direction in which the droplets are ejected from the nozzle. Figures 6D to 6F yes Figures 6A to 6C A sectional view.

[0085] in addition, Figure 7A yes Figure 6C Overall floor plan. Figure 7B and Figure 7C It shows along Figure 7A Examples of two cross-sectional views of AB. Although the shape of the back side of the substrate varies depending on the type of etching method performed on the substrate... Figure 7B and Figure 7C Two examples are shown, but the cross-section can have any shape.

[0086] exist Figures 6A to 6F and Figures 7A to 7CIn this configuration, a liquid injection nozzle 11 is formed in an orifice plate 19. A first energy generating element 14 is formed in a substrate 18 directly below the injection nozzle 11. Similarly, a second energy generating element 24 is formed in the substrate 18 together with the first energy generating element 14 to form a circulating flow 27 in a single-use flow path 23. Liquid is supplied from supply ports 22 and 32 to the single-use flow path 23 including the injection nozzle 11. At this time, the two ends of each single-use flow path are arranged in opposite positions relative to a second direction that perpendicularly intersects the first direction, which is the direction in which the injection nozzles are arranged.

[0087] In such Figures 6A to 6F and Figures 7A to 7C In the straight flow path shown, as described above, a circulating flow is used by placing the second energy generating element 24 at an asymmetrical position. In this case, the side with lower flow resistance from the second energy generating element 24 to the end of the single-use flow path is used as the inlet (upstream), while the side with higher flow resistance from the second energy generating element 24 to the end of the single-use flow path is used as the outlet (downstream). Therefore, in terms of circulating flow rate, it is preferable to set a small flow resistance at the inlet side of the second energy generating element 24 and a large flow resistance at the outlet side of the second energy generating element. However, if only the flow resistance at the outlet side of the second energy generating element 24 is increased, the length of the single-use flow path increases, which is accompanied by an increase in the substrate size and head size. Therefore, in terms of circulating flow rate, it is preferable to set a large flow resistance at the outlet side of the second energy generating element 24 while shortening the flow path length.

[0088] On the other hand, regarding the flow resistance at the outlet side of the second energy generating element 24, the flow resistance at the outlet side of the first energy generating element 14 is preferably small because this part serves as the main supply section for replenishing the liquid during injection in an amount corresponding to the amount of liquid ejected. Therefore, from the viewpoint of achieving both circulating flow rate and replenishment performance during injection, it is preferable and important to set a large flow resistance between the first energy generating element 14 and the second energy generating element 24. At this time, it is also possible to reduce interference (crosstalk) between the first energy generating element 14 and the second energy generating element 24.

[0089] Therefore, as Figure 6AAs shown, this embodiment is characterized by including a high-resistance structure 51 at the center of the flow path between the first energy generating element 14 and the second energy generating element 24. Therefore, by setting a small flow resistance at the inlet side of the second energy generating element 24 and a large flow resistance at the outlet side of the second energy generating element 24, the circulating flow rate can be ensured. Furthermore, by setting a large flow resistance between the first energy generating element 14 and the second energy generating element 24, thereby setting a small flow resistance at the outlet side of the first energy generating element 14, the supplementary performance during injection can also be ensured. In this way, both the circulating flow rate and the supplementary performance during injection can be achieved by locally providing a region with a large flow resistance between the first energy generating element 14 and the second energy generating element 24. Here, this can be understood as locally providing a region with a reduced cross-sectional area in the circulation direction. 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.

[0090] Note that although the high-resistance structure 51 at the center of the flow path is shown as a cylindrical structure in this embodiment, other columnar structures can be used from the viewpoint of increasing flow resistance. For example, the high-resistance structure 51 can be a quadrangular prism or a triangular prism. Furthermore, the high-resistance structure 51 can be a columnar structure whose length extends in the flow path direction when viewed from the top (e.g., a rounded rectangle), and multiple columnar structures can be provided for each high-resistance structure 51. However, regardless of the cross-sectional shape, the resistance can be further increased in the state with the high-resistance structure 51 provided compared to the state without it, and thus an effect can be obtained to some extent.

[0091] Figure 6B This is a variant where the filter 31 is disposed on both sides of the single-use flow path. The filter 31 is used to prevent foreign matter contained in the ink and supply path from entering the single-use flow path. The filter 31 is arranged at the portion connected to the common flow path. This is a countermeasure to the concern that if foreign matter gets mixed in near the first energy generating element, ink ejection from the ejector nozzle may not occur, or the image in the printed object may be degraded due to poor ejection. Similar to... Figure 6A ,exist Figure 6B It can also balance achieving circulating flow and supplementary performance during injection. Figure 6B In the example, filter 31 is arranged on a side upstream of the second energy generating element 24 (the side closer to the first supply port 22) and on a side downstream of the first energy generating element 14 (the side closer to the second supply port 32).

[0092] Figure 6CThis is a variant in which a filter 31 is provided only on the side of the first energy generating element in each single-use flow path. This is achieved from the viewpoint of providing a filter structure in the main supply section to replenish the amount of liquid ejected during injection. This is also achieved by providing a high-resistance structure on the opposite side in each single-use flow path. Furthermore, with Figure 6B In comparison, the flow resistance on the inlet side of the second energy-generating element is reduced because no filter is installed on that side. Conversely, the flow resistance on the outlet side of the second energy-generating element is increased because a filter is retained on that side. Therefore, it can be said that, from the viewpoint of circulating flow, Figure 6C Compare Figure 6B More preferably.

[0093] Figure 7A It shows the use of Figure 6C The flow path shown is an example of an overall structure forming multiple flow paths. A first supply port 22 and a second supply port 32 are respectively located on the inlet side (upstream) and outlet side (downstream) of a single-use flow path. Therefore, by forming multiple injection ports, this structure serves as a liquid injection head. Although this also applies to... Figure 6A and Figure 6B And will be described later Figures 9A to 9D and Figures 10A to 10F However, only one flow path is shown among them. Furthermore, Figures 11A to 11C Used in conjunction with subsequent attached figures Figure 6C The flow path shown is illustrated as an example of the overall construction.

[0094] Figures 8A to 8C It is a graph showing the circulating flow rate in each flow path configuration. Figure 8A This is a plan view of each single-use flow path as seen from the direction of droplet ejection from the nozzle in a comparative example excluding the high-resistance structure. Figure 8B yes Figure 8A A sectional view. Figure 8C It concerns structures shown in the plan view that do not have high resistance. Figure 8A and the high-resistance structure according to this embodiment Figure 6C The graph shows the average circulating flow rate derived from simulation when the circulating heater (i.e., the second energy generating element) is driven once. Here, due to the velocity distribution along the cross-sectional direction, the average circulating flow rate (i.e., the circulating flow rate averaged over the cross-sectional area) is shown. Note that the circulating flow rate is obtained by... Figure 8C It is obtained by integrating along the horizontal axis.

[0095] from Figure 8CIt can be confirmed that, compared with the comparative example, the average circulating flow rate is higher and the circulating flow rate is also larger in this embodiment including the high-resistance structure. The simulation was performed under the assumptions of a flow path height of 24 μm, a pressure chamber width of 30 μm, a flow path width excluding the pressure chamber width of 28 μm, a heater size of 15 μm × 15 μm for the circulating heater as the second energy generating element, a flow path length of 115 μm, and a viscosity of 4 cp for the liquid to be circulated. Furthermore, under other dimensions and conditions, the circulating flow rate is increased in a similar manner by including the high-resistance structure. As described above, it can be confirmed that the circulating flow rate is improved by including a high-resistance structure at the center of the flow path between the first and second energy generating elements.

[0096] Driving method in the embodiment: switching drivers

[0097] In this embodiment, as Figure 13 The selective drive circuit 200 shown is formed on the substrate 18. A voltage source and controller 110 are disposed outside the substrate 18 and connected to the selective drive circuit 200 on the substrate 18. An on-off drive circuit (a first switch that performs switching between on and off) 230 is included, which, in response to a control signal received from the control data supply circuit 100 at each address (N1 to N16 in this embodiment), turns on the first energy generating element (A1 to A16) or the second energy generating element (B1 to B16) to drive them.

[0098] In other words, it includes a switch configured to perform exclusive switching such that only the first energy-generating element or only the second energy-generating element is in an drivable state. Using this switch, when the first energy-generating element is drivable, the second energy-generating element is always in a non-drivable state; conversely, when the second energy-generating element is drivable, the first energy-generating element is always in a non-drivable state. Here, the control data supply circuit 100 controls the drive pulses used to drive the first or second energy-generating element and the time interval for applying the drive pulses to each element.

[0099] Even when the on-off drive circuit 230 selects the second energy generating element side, the on-off drive circuit 240 of the second energy generating element (the second switch that performs switching between on and off) also controls the drive in response to the drive enable / disable signal 300 of the second energy generating element. In other words, the second energy generating element is also controlled by a switch configured to perform switching between a driveable state and an inoperable state. Therefore, although the second energy generating element is in a driveable state when the first energy generating element is inoperable, the second energy generating element is only actually driven when a drive signal (drive enable / disable signal) for providing a drive command to the second energy generating element is received. Without a drive enable / disable signal, the second energy generating element will not be driven even if the on-off drive circuit 230 has selected the second energy generating element side. In other words, neither the first nor the second energy generating element is driven at this time.

[0100] In summary, the drive circuit configured in this embodiment to control the driving of the first energy generating element and the second energy generating element includes a first switch configured to perform exclusive switching such that only the first energy generating element or only the second energy generating element can be driven, and includes a second switch configured to perform switching between a driveable state and an indriveable state for the second energy generating element, and controls the driving of the first energy generating element and the second energy generating element under the following conditions by using the drive circuit.

[0101] -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 for giving a drive command to the second energy generating element is received.

[0102] Furthermore, it is preferable that the on-off drive circuit (second switch) is located closer to the second energy generating element than the on-off drive circuit (first switch), i.e., on the downstream side relative to the second energy generating element. Furthermore, it is preferable to use a common drive signal to control the drive of the multiple second energy generating elements.

[0103] In this control, the controller 110 and the control data supply circuit 100 can be considered as a drive control unit that controls the drive of the first energy generating element and the second energy generating element.

[0104] In addition to the aforementioned switching drive, drive control can be performed so that the drive of the first energy generating element and the drive of the second energy generating element are each controlled individually.

[0105] Second Embodiment

[0106] Figures 9A to 9D This is a schematic diagram showing the vicinity of the nozzle of a liquid jetting head for detailing the jetting of a liquid (such as ink) according to the second embodiment. Figures 9A to 9C It is a plan view of each single-use flow path as seen from the direction in which the droplets are ejected from the nozzle. Figure 9D yes Figures 9A to 9C Common cross-sectional view. Note that, in addition to the configuration of this embodiment, filters can also be provided on both sides of the single-use flow path or only on the side of the first energy generating element. In this case, the filter can be set in a configuration similar to... Figure 6B and Figure 6C The location in the middle.

[0107] This embodiment differs from the first embodiment in that a narrowing structure 52 with a narrowed flow path width is provided between the first energy generating element 14 and the second energy generating element 24. In this embodiment, Figure 9A An example is shown where the narrowing structure 52 is disposed at the flow path portion between the first energy generating element 14 and the second energy generating element 24. Additionally, Figure 9B A variation is shown where the narrowed structure 52 is disposed at a longer portion of the flow path between the first energy generating element 14 and the second energy generating element 24. Furthermore, Figure 9C A variant example of a narrowing structure 52 with a flow path width that narrows continuously rather than discontinuously is shown. In other words, in Figure 9B In the middle, the flow path width is changed between the part with narrow flow path width and the part with wide flow path width, while... Figure 9C In this process, the flow path width changes continuously. The narrowing structure 52 is a resistance structure that increases the flow resistance between the first energy generating element 14 and the second energy generating element 24.

[0108] As an advantage achieved by this construction, similar to 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 achieve both circulating flow rate and supplementary performance during injection while shortening the flow path. Furthermore, since a narrowed structure 52, integrated with the flow path wall forming the single-purpose flow path, is provided instead of forming the high-resistance structure 51 as a single unit as in the first embodiment to increase flow resistance, the adhesion to the substrate is increased and the structure becomes less prone to peeling.

[0109] Here, it is preferable to obtain the length of the narrowing structure 52 in the circulation direction by excluding the lengths of the first energy generating element 14 and the second energy generating element 24. This is because the large difference between the left and right flow resistances relative to the first energy generating element 14, and the fact that the flow path walls are close to or overlap with the first energy generating element itself, will affect the injection. Regarding the second energy generating element 24, this is because: the overlap of the flow path walls with the second energy generating element itself will affect foaming or reduce the foam size of the second energy generating element 24, which will lead to a reduction in the circulation flow rate.

[0110] Third Embodiment

[0111] Figures 10A to 10F This is a schematic diagram showing the vicinity of the nozzle of a liquid jetting head for detailing the jetting of a liquid (such as ink) according to the third embodiment. Figures 10A to 10C It is a plan view of each single-use flow path as seen from the direction in which the droplets are ejected from the nozzle. Figures 10D to 10F They are Figures 10A to 10C A cross-sectional view. Note that, in addition to the configuration of this embodiment, filters can also be provided on both sides of the single-use flow path or only on the side of the first energy generating element. In this case, the filter can be set in a configuration similar to... Figure 6B and Figure 6C The location in the middle.

[0112] This embodiment differs from the first embodiment in that a stepped structure 53 with a narrowed flow path height is provided between the first energy generating element 14 and the second energy generating element 24. In this embodiment, Figure 10A An example is shown where the stepped structure 53 is disposed at the upper part of the flow path portion between the first energy generating element 14 and the second energy generating element 24. Additionally, Figure 10B A variation of the stepped structure 53 is shown, located at the lower part of the flow path section. Furthermore, Figure 10C A variation of the stepped structure 53 is shown, located at the lower part of a longer portion of the flow path between the first energy generating element 14 and the second energy generating element 24. The stepped structure 53 is a resistance structure that increases the flow resistance between the first energy generating element 14 and the second energy generating element 24.

[0113] Here, in the case of the step structure 53 at the upper part of the flow path, the step structure 53 can be the same component as the orifice plate 9 on which the nozzle is formed. Although the step structure 53 is shown in the figure as extending throughout the width direction of the flow path, the step structure 53 can be provided at a portion of the width direction of the flow path. Furthermore, in the case of the step structure 53 at the lower part of the flow path, the step structure 53 can be the same component as the orifice plate 9, or it can be a local structure such as a circuit formed in the substrate. Although the step structure 53 at the lower part is also shown at a portion of the width direction of the flow path, the step structure can extend throughout the width direction of the flow path. Here, from the viewpoint of the fit caused by the difference between the flow path wall of the single-use flow path extending above or below the step or the difference between the flow path wall material of the single-use flow path and the outermost surface material of the substrate, the step structure is shown at a portion of the width direction of the flow path. Note that in this disclosure, the direction from the first energy generating element 14 to the nozzle 11 in the single-use flow path 23 is defined as the height direction, and the direction perpendicular to the height direction and the extension direction of the single-use flow path 23 is defined as the width direction.

[0114] As an advantage achieved by this construction, similar to 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 achieve both a shortened flow path and sufficient supplementary performance during injection. Since the stepped structure 53 is formed at the upper or lower part to increase flow resistance, adhesion to the substrate is less of a problem. For example, if the stepped structure 53 at the upper part of the flow path is integrated with the orifice plate 9 as a single component, adhesion to the substrate is not a concern. Similarly, if the stepped structure 53 at the lower part of the flow path is a local structure formed within the substrate, adhesion to the substrate is also not a concern.

[0115] Here, as described above for the narrowing structure 52, it is preferable to obtain the length of the stepped structure 53 in the cyclic direction by excluding the lengths of the first energy generating element 14 and the second energy generating element 24. Furthermore, this is also because, in the case where the stepped structure 53 at the lower part is a local structure such as a circuit formed in the substrate, the first energy generating element 14 and the second energy generating element 24 are similarly formed.

[0116] Fourth embodiment

[0117] Figures 11A to 11C This is a schematic diagram of the vicinity of the injection port of a liquid injection head for detailing the injection of liquid (such as ink) according to the fourth embodiment. Figure 11A It is a plan view taken along the direction in which the droplets are ejected from the nozzle. Figure 11B and Figure 11C Similar to Figure 7B and Figure 7C That shows along Figure 11A Examples of two sections of AB in the diagram.

[0118] This embodiment differs from the second embodiment in that the injection port array is arranged in a double-row configuration by providing three supply port rows, with each injection port row located on one side closer to the center supply port row. In other words, the injection port rows are formed on both sides of the arrangement direction of the multiple supply ports. The injection port row is an arrangement of injection ports 11 included in a unit row of multiple single-use injection units. In this embodiment, the first unit row and the second unit row are arranged parallel to each other. Here, the central opening row shared by the first and second unit rows is defined as the second opening row with second openings arranged therein. Furthermore, the end opening rows of the first and second unit rows are defined as the first opening row with first openings arranged therein.

[0119] As an advantage of this configuration, the number of injection nozzle columns can be doubled from one column to two columns by increasing the number of supply ports from two columns to three columns. The two injection nozzle columns can also be arranged with offset spacing as shown in the figure. Furthermore, a configuration that eliminates the need for a wiring area between the openings in the central supply port column is also possible, and the opening size and resolution at the central supply port column offer high flexibility. In this way, the nozzle replenishment speed can be increased and high productivity can be easily achieved.

[0120] Note that although the three supply port columns are in the same position in the direction between nozzles in this embodiment, these three columns can be offset according to the nozzle position in each column or the wiring arrangement between the openings. This also applies to the following embodiments.

[0121] Fifth embodiment

[0122] Figure 12A and Figure 12B This is a schematic diagram showing the vicinity of the nozzle of a liquid jetting head for detailing the jetting of a liquid (such as ink) according to the fifth embodiment. Figure 12A It is a plan view taken along the direction in which the droplets are ejected from the nozzle. Figure 12B It is along Figure 12A The sectional view of AB in the diagram.

[0123] This embodiment differs from the third embodiment in that the direction of the circulating flow is reversed by positioning the jet nozzle array on the side closer to the two side supply nozzle arrays and by positioning the second energy generating element 24 on the side closer to the center supply nozzle array.

[0124] As an advantage of this configuration, the ink concentrated near the nozzle is branched and discharged from the supply port rows on both sides, thus suppressing the effect of concentrated ink when it flows back into the single-use flow path in response to jetting. Furthermore, since the nozzle rows are arranged spaced apart from each other, the interference caused by meniscus vibrations associated with jetting from each nozzle is suppressed.

[0125] As described above, the object of this disclosure is to provide a liquid jet head that can maintain desired circulation efficiency and circulation flow rate while further reducing the size of the head and recording device by shortening the circulation flow path and reducing the substrate size. Therefore, the adopted structure includes multiple single-purpose jet units, each including a jet nozzle, a pressure chamber, a first energy generating element disposed in the pressure chamber, a single-purpose flow path communicating with the pressure chamber, and a second energy generating element disposed in the single-purpose flow path. In the single-purpose jet unit, the direction of the jet nozzle array arrangement and the extension direction of the single-purpose flow path including the first and second energy generating elements intersect each other, and the flow resistance or the cross-sectional area of ​​the flow path increases or decreases between the first and second energy generating elements. Specifically, instead of extending the flow path, the flow resistance on one side of the second energy generating element is increased by providing a high-resistance structure, a narrowing structure, a stepped structure, etc., in the single-purpose flow path. Therefore, a liquid jet head can be provided that can improve circulation efficiency and ensure circulation flow rate without extending the circulation flow path.

[0126] According to this disclosure, a liquid jet head can be provided that can achieve the desired circulation efficiency and maintain circulation flow rate while shortening the circulation path and reducing the substrate size.

[0127] While this disclosure has been described with reference to embodiments, it is to be understood that this disclosure is not limited to the disclosed embodiments. The scope of the following claims should be given the broadest interpretation to cover all variations and equivalent structures and functions.

Claims

1. A liquid ejection head comprising: a single-use ejection unit including an ejection port that ejects a liquid, a pressure chamber that communicates with the ejection port, a first energy generating element that is provided in the pressure chamber and generates thermal energy for ejecting the liquid from the ejection port, a single-use flow path that communicates with the pressure chamber, and a second energy generating element that is provided in the single-use flow path and generates thermal energy; and a common flow path configured to supply the single-use flow paths of a plurality of single-use ejection units with a liquid, wherein a plurality of ejection ports included in the plurality of single-use ejection units form an ejection port row, the first energy generating element and the second energy generating element are arranged in the single-use flow path of the single-use ejection unit in a direction that intersects the ejection port row, the single-use flow path extends in a direction that intersects the ejection port row so that both end portions of the single-use flow path are positioned so that the ejection port row is between the both end portions, and the single-use flow path is provided with a resistance structure that increases a flow resistance between the first energy generating element and the second energy generating element.

2. The liquid ejection head according to claim 1, wherein the second energy generating element is not driven in a case where the first energy generating element is driven, and the second energy generating element is driven when a drive signal for providing a drive instruction to the second energy generating element is received in a case where the first energy generating element is not driven.

3. The liquid ejection head according to claim 2, further comprising: a drive control unit configured to control the drive of the first energy generating element and the second energy generating element.

4. The liquid ejection head of claim 1, wherein the drive of the first energy generating element and the drive of the second energy generating element are individually controlled separately.

5. The liquid ejection head of claim 1, wherein the resistance structure is a columnar structure provided at a center of the single-use flow path.

6. The liquid ejection head of claim 1, wherein the resistance structure is a structure that narrows a cross-sectional area of the single-use flow path between the first energy generating element and the second energy generating element.

7. The liquid ejection head of claim 6, wherein when a direction in the single-use flow path from the first energy generating element to the ejection port is defined as a height direction and a direction that perpendicularly intersects the height direction and a direction in which the single-use flow path extends is defined as a width direction, the resistance structure is a narrowing structure that is provided in the width direction of the single-use flow path and has a narrowed flow path width.

8. The liquid ejection head of claim 7, wherein, in the narrowing structure, the flow path width continuously changes between a portion having the narrowed flow path width and a portion having a wide flow path width.

9. The liquid ejection head of claim 6, wherein when a direction in the single-use flow path from the first energy generating element to the ejection port is defined as a height direction, the resistance structure is a step structure that narrows the single-use flow path in the height direction.

10. The liquid ejection head of claim 9, wherein, the step structure is provided at the first energy generating element side in the height direction, and is configured as a portion 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 any one of claims 6 to 10, wherein the resistance structure is provided in a region between the first energy generating element and the second energy generating element in the single-use flow path.

12. The liquid ejection head of claim 9 or 10, wherein, the step structure is provided at a portion of the single-use flow path in the width direction.

13. The liquid ejection head according to any one of claims 1 to 10, wherein the single-use flow path is connected to the common flow path at both end portions thereof, and a filter is provided at portions of the both end portions that are connected to the common flow path.

14. The liquid ejection head according to any one of claims 1 to 10, wherein the single-use flow path is connected to the common flow path at both end portions thereof, and The filter is provided on the first energy generating element side among both end portions of the single-use flow path.

15. The liquid ejection head according to any one of claims 1 to 10, wherein The common flow path and the plurality of single-use flow paths included in the plurality of single-use ejection units are connected via the openings.

16. The liquid ejection head according to any one of claims 1 to 10, wherein one end portion and the other end portion of each single-use flow path are connected to the common flow path via a first opening and a second opening, respectively, and the plurality of first openings and the plurality of second openings included in the plurality of single-use ejection units are aligned with ejection port rows that are rows of the ejection ports included in the plurality of single-use ejection units.

17. The liquid ejection head according to any one of claims 1 to 10, wherein one end portion and the other end portion of each single-use flow path are connected to the common flow path via a first opening and a second opening, respectively, the plurality of single-use ejection units are arranged in a direction that intersects perpendicularly with a single-use flow path extension direction to constitute a unit row, and a first unit row and a second unit row are arranged in parallel with each other, the single-use flow paths included in the first unit row and the single-use flow paths included in the second unit row share the second openings, and the plurality of shared second openings are arranged in the direction that intersects perpendicularly with the single-use flow path extension direction to form a second opening row, and the first openings included in the first unit row and the first openings included in the second unit row are arranged in the direction that intersects perpendicularly with the single-use flow path extension direction to form a plurality of first opening rows.

18. The liquid ejection head of claim 17, wherein, In each of the plurality of single-use flow paths, the first energy generating element is provided on a side close to the second opening.

19. The liquid ejection head according to any one of claims 1 to 10, wherein the second energy generating element performs a circulation drive that circulates the liquid in the single-use flow path, and the first energy generating element performs an ejection drive that ejects the liquid from the ejection port.

20. The liquid ejection head of claim 19, wherein, The circulation drive is a drive that requires less energy than the ejection drive. The circulation drive is a drive that requires less energy than the ejection drive.

Images