Liquid ejecting head

Abstract

A liquid ejection head includes a first independent ejection unit, a second independent ejection unit, and a common flow channel for supplying liquid. Each of the first and second independent injection units includes an injection port, a pressure chamber, a first energy generating element disposed in the pressure chamber, an independent flow channel in communication with the pressure chamber, and a second energy generating element disposed in the independent flow channel. The liquid ejecting head is characterized in that the first energy generating element and the second energy generating element in each ejecting unit are differently controlled at a common driving timing for each independent ejecting unit by means of a common driving pulse.

Description

Technical Field

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

[0002] A circulating liquid jetting device is known that circulates ink to expel air bubbles in the flow channel and suppresses an increase in ink viscosity near the jet port in the liquid jetting head (hereinafter also referred to as the "printhead"). The method of using pressure difference (hereinafter also referred to as the "differential pressure method") is widely known as a method for circulating ink. In this method, a pressure regulating mechanism or similar mechanism is used to make the pressure on the side where ink is supplied to the jet port (inner side) higher than the pressure on the side where ink is collected (outer side), thereby causing ink to flow from the inner side to the outer side. In this case, to circulate the ink, it is necessary to return the ink flowing to the inner side, and a pump is used as the mechanism for this. Alternatively, a pump can be installed outside the printhead (such as on the recording device body) to circulate the liquid between the liquid jetting head and the body, or a pump can be installed inside the liquid jetting head to circulate the liquid within the liquid jetting head. However, this differential pressure circulation method uses mechanisms such as pressure regulating mechanisms and pumps, and the recording device body and printhead tend to be relatively large.

[0003] Therefore, ink circulation methods other than differential pressure methods have been considered. Specifically, a mechanism is known in which a circulation flow channel is provided in communication with the jet port, and an energy generating element other than the energy generating element for ink jetting (hereinafter also referred to as the "jet energy generating element") is provided in the circulation flow channel, and ink is circulated in the circulation path by driving the flow energy generating element.

[0004] Japanese Patent Application Publication No. 2020-104312 discloses a configuration in which a circulating flow channel is provided, the circulating flow channel extending to intersect with a row of injection ports in which a plurality of injection ports are arranged, and a flow energy generating element is provided in the circulation path.

[0005] Japanese Patent Application Publication No. 2020-104312 does not describe what kind of drive pulse or drive timing is used to drive the jet energy generating element and the flow energy generating element. Generally, it is conceivable that only the drive of the jet energy generating element is utilized (diverted) to generate drive pulse waveforms corresponding to each energy generating element, and that drive timing is set to provide a delay for each time-division block, while allocating each drive pulse waveform under time-division control. However, this results in the following problem: the circuit size increases with the type and number of energy generating elements.

[0006] Therefore, it would be useful to reduce the circuit size in ink-circulating liquid jet heads that use both jet energy generating elements and flow energy generating elements. Summary of the Invention

[0007] This disclosure advantageously provides features for solving these problems, and according to some embodiments, a liquid jet head includes a first independent jetting unit; a second independent jetting unit; and a common flow channel, wherein each of the first and second independent jetting units includes: a jetting port configured to jet liquid; a pressure chamber in communication with the jetting port; a first energy generating element disposed in the pressure chamber and configured to generate energy for jetting liquid from the jetting port; an independent flow channel in communication with the pressure chamber; and a second energy generating element disposed in the independent flow channel, wherein the common flow channel supplies liquid to the independent flow channel for each of the first and second independent jetting units, wherein the first and second energy generating elements in each of the first and second independent jetting units are driven by a common drive pulse, wherein the first and second energy generating elements in the first independent jetting unit are driven at the same timing (i.e., a first timing), wherein the first and second energy generating elements in the second independent jetting unit are driven at the same timing (i.e., a second timing), and wherein the first and second timings are controlled to be different from each other.

[0008] The features of this disclosure will become apparent from the following description of embodiments with reference to the accompanying drawings. The following description of the embodiments is by way of example. Attached Figure Description

[0009] Figure 1A and Figure 1B This is a schematic diagram of a device that uses a liquid injection head.

[0010] Figures 2A to 2D This is a schematic diagram of the integral liquid jet head and the integral liquid jet chip.

[0011] Figures 3A to 3D This is a schematic diagram of the area near the injection port of the liquid jet nozzle.

[0012] Figures 4A to 4C This is a schematic diagram of the area near the injection port of the liquid jet nozzle.

[0013] Figures 5A to 5D This is a schematic diagram of the area near the injection port of the liquid injector.

[0014] Figures 6A to 6D This is a schematic diagram of the area near the injection port of the liquid injector.

[0015] Figures 7A to 7C This is a schematic diagram of the area near the injection port of the liquid injection head in the first embodiment.

[0016] Figure 8 This is a circuit configuration diagram for a comparative configuration.

[0017] Figure 9 This is the first circuit configuration diagram in the first embodiment.

[0018] Figure 10 This is the second circuit configuration diagram in the first embodiment.

[0019] Figures 11A to 11C This is a schematic diagram of the area near the injection port of the liquid injection head in the second embodiment.

[0020] Figures 12A to 12C This is a schematic diagram of the area near the injection port of the liquid injection head in the third embodiment.

[0021] Figure 13A and Figure 13B This is a schematic diagram of the area near the injection port of the liquid injection head in the fourth embodiment.

[0022] Figure 14A and Figure 14B This is a schematic diagram of the area near the injection port of the liquid injection head in the fifth embodiment.

[0023] Figures 15A to 15C This is a schematic diagram of the area near the injection port of the liquid injection head in the sixth embodiment. Detailed Implementation

[0024] Various exemplary embodiments, features, and aspects of this disclosure will now be described in detail with reference to the accompanying drawings. It should be noted that the following embodiments do not limit the scope of this disclosure, and not all combinations of features described in these embodiments are necessary for the solutions of this disclosure. Identical components are indicated by the same reference numerals and symbols. In the following description, the basic configuration of this disclosure will be described first, followed by its features.

[0025] Liquid injection device

[0026] First, a schematic configuration of the liquid injection device 50 in this embodiment will be described. Figure 1A and Figure 1B This is an enlarged view of the liquid injection head 1 and its surrounding area of ​​the liquid injection device 50.

[0027] Figure 1A and Figure 1B This is a schematic perspective view of a liquid injection device using a liquid injection head. Figure 1A and Figure 1BThe liquid ejection device 50 shown is a serial liquid ejection device (serial liquid ejection device) that records images by ejecting liquid onto the recording medium P using a liquid ejection head that scans in a direction intersecting with the transport direction of the recording medium P. This disclosure is not limited to serial liquid ejection devices, but also applies to page-width liquid ejection devices, which record images by ejecting liquid onto the recording medium transported in the transport direction using a line-type printhead (page-width printhead) that is longer along the page width direction of the recording medium. The liquid ejection head in this embodiment can eject four types of ink, including 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 also applies to liquid ejection heads used for ejecting other types of ink. That is, the type and quantity of ink ejected from the liquid ejection head are not limited.

[0028] In the serial liquid jetting device 50, the liquid jetting head 1 is mounted on a carriage 60. The carriage 60 moves back and forth along the guide shaft 51 in the main scanning direction (X direction). The recording medium is conveyed by transport rollers (transport devices) 55, 56, 57, and 58 in a secondary scanning direction (Y direction) that intersects (in this example, is perpendicular) the main scanning direction. In the figures below, the Z direction represents the vertical direction and intersects (in this example, is perpendicular) the XY plane defined by the X and Y directions.

[0029] Figure 1A This diagram shows a configuration in which the main ink cartridge 2 is positioned externally to the liquid ejector head as a liquid retention section. The liquid (ink) retained in cartridge 2 is supplied to the auxiliary ink cartridge 54 located on the side of the liquid ejector head 1 via an ink supply tube (liquid communication path) 59 under the driving force of an external pump 28. In contrast, Figure 1B The diagram shows a configuration in which the ink cartridge 54 is positioned directly above the liquid ejector head 1 (without the main ink cartridge 2 serving as a liquid retention portion outside the liquid ejector head). In this case, the liquid ejector head 1 can be integrally formed with the ink cartridge 54 and configured such that the carriage 60 can be detached from and attached to the ink cartridge. Alternatively, the liquid ejector head 1 can also be integrally formed with the carriage 60 and configured such that only the ink cartridge 54 can be removed from and attached to the carriage. (The last sentence appears to be a fragment and doesn't translate directly.) Figure 1A The following description is given as a typical example of the configuration.

[0030] Liquid injection head 1 is configured to include a separate injection unit, which will be described later (see [link to documentation]). Figures 2A to 2DWhile its specific configuration will be described later, the independent 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, an independent flow channel communicating with the pressure chamber, and a second energy generating element (flow energy generating element) disposed in the independent flow channel. The liquid injection head 1 has multiple independent injection units and has an opening as a supply flow channel for supplying liquid to the independent flow channel in each independent injection unit.

[0031] When using a liquid ejector head, the ejection of the liquid can become unstable due to the evaporation of volatile components such as water from the ejection port, causing the solid components near the ejection port to concentrate. Various measures have been considered to prevent this. For example, the liquid ejection device may have a cover member (not shown) positioned in the X direction offset from the transport path of the recording medium. This cover member covers the ejection port surface of the liquid ejector head. The cover member is used to cover the ejection port surface of the liquid ejector head when no recording operation is performed, preventing the ejection port from drying out and protecting the ejection port. Furthermore, an ink suction mechanism (not shown) may be provided. In this case, the cover member is used to suction ink from the ejection port. By performing the ink suction operation, the ink near the ejection port can be refreshed, and the quality level of the obtained image can be maintained. In addition, methods are known to discard concentrated ink by performing a jetting operation called pre-jet (pre-jet) when no recording operation is performed, and even during recording operation, to pre-jet ink in an inconspicuous location and in an amount inconspicuous to the image quality on the recording medium (paper pre-jet or in-page pre-jet). While these methods greatly improve image quality, the amount of waste ink can be minimized as some ink is discarded to refresh the jet port.

[0032] To address this issue, a second energy-generating element (flow energy generating element) is incorporated into an independent flow channel, allowing the ink to circulate within the channel. This prevents the ejection port from drying out and ink concentration near the ejection port, while minimizing waste ink. More specifically, it reduces the number of pre-ejection and suction recovery operations as much as possible. Furthermore, minimizing the number of pre-ejection operations, etc., can increase production volume and output.

[0033] The second energy generating element (flow energy generating element) need not be provided in all the individual injection units of the liquid jet head. When the element is provided in some of the individual injection units, the above-mentioned effects can be obtained compared to the case where the element is not provided.

[0034] also, Figure 1A The liquid jet head shown can be configured such that a second energy generating element is provided at all positions corresponding to the four types of ink, or such that a second energy generating element is provided at only the position corresponding to one type of ink. In other words, the liquid jet head can be configured to circulate only at least one type of ink, without circulating all four types of ink.

[0035] Basic configuration of liquid injection head

[0036] 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 ejector head is configured to include a sub-ink cartridge 54 that temporarily retains ink in the printhead, and a liquid ejection chip 3 that ejects ink supplied from the sub-ink cartridge 54 onto the recording medium P. According to this embodiment, the liquid ejector head is fixedly supported on the carriage of the liquid ejection device by a positioning device and electrical contacts (not shown) provided on the carriage. The liquid ejector head moves along... Figure 1A and Figure 1B As shown, the main scanning direction (X direction) moves together with the carriage while ink is ejected, thereby recording on the recording medium P.

[0037] Ink supply tube 59 is mounted on external pump 28 connected to ink cartridge 2, and each ink cartridge serves as an ink supply source (see [link]). Figure 1A A liquid connector (not shown) is provided at the front end of the ink supply tube. When the liquid ejector head 1 is mounted on the liquid ejection device 50, the liquid connector at the front end of the ink supply tube 59 is connected to the liquid connector insertion port (which is the liquid inlet port provided on the nozzle housing of the liquid ejector head 1) in a liquid-proof manner. This forms an ink supply path from the ink cartridge 2 to the liquid ejector head 1 via the external pump 28. In this embodiment, since four types of ink are used, four sets of ink cartridges 2, external pumps 28, ink supply tubes 59, and sub-ink cartridges 54 are provided corresponding to the respective inks, and four ink supply paths are independently formed corresponding to the respective inks. As described above, the liquid ejection device according to this embodiment is provided with an ink supply system, to which ink is supplied from the ink cartridge 2 located outside the liquid ejector head 1. It should be noted that the liquid ejection device according to this embodiment does not include an ink collection system for collecting ink from the liquid ejector head to the ink cartridge. Therefore, the liquid ejector head is provided with a liquid connector insertion port for connecting the ink supply tube to the ink cartridge, but no connector insertion port is provided for connecting the tube used to collect ink from the liquid ejector head to the ink cartridge. It should be noted that a liquid connector insertion port is provided for each type of ink.

[0038] Figure 2B , Figure 2C and Figure 2D This is an overall diagram of the liquid jetting chip that makes up the liquid jetting head. Figure 2BThe configuration of a single chip for four colors is shown. Figure 2C The configuration of a single chip for two colors is shown, and Figure 2D The configuration of one chip for one color is shown. Each liquid jet chip is provided with a jetting port and pads for electrical mounting. Figure 2A It shows Figure 2B The chip configuration.

[0039] Figure 2B A first embodiment is shown, in which a chip is provided for four colors. These four colors are, for example, black, cyan, magenta, and yellow, and rows for each color are aligned along the Y-direction. The spray ports in each row are adjacent and offset in the X-direction, and are equidistant along the Y-direction. Alternatively, the spray ports in each row can be arranged in a single row along the Y-direction without offset in the X-direction. Furthermore, two rows can be provided for black, and a total of five rows can be provided for the four colors.

[0040] Figure 2C A second embodiment is shown, in which two chips are used, with each chip being provided for two colors. When two chips are installed on a liquid nozzle, the two chips can be installed on one liquid nozzle, or two liquid nozzles can be provided, with one chip installed on each liquid nozzle.

[0041] Figure 2D A third embodiment is shown, in which four chips are used, such that each chip is provided for one color. For example... Figure 2C As shown, four chips can be installed on one liquid injection head, or four liquid injection heads can be set up, with one chip installed on each injection head.

[0042] In addition, such as Figure 2C and Figure 2D As shown, when a chip is divided into multiple chips, all chips do not necessarily have the same chip length. Furthermore, various combinations of different numbers of colors can be made for the chips, even when the total number of colors is greater than four.

[0043] The constituent elements of a loop unit

[0044] in-line

[0045] Figures 3A to 3D A schematic diagram of the area near the injection port of each in-line liquid injector head is shown. In this specification, "in-line" refers to the direction intersecting the row of injection ports (in...). Figures 3A to 3DThe shape is a straight line extending perpendicular to the direction of the injection port row, such that the two end portions of the independent flow channel in which the first energy generating element (injection energy generating element) and the second energy generating element (flow energy generating element) are located on both sides of the injection port row between them. In other words, the first energy generating element and the second energy generating element are arranged in the independent flow channel of the independent injection unit along a direction intersecting the injection port row.

[0046] Figure 3A This is a plan view observed from the direction of the ejected droplets at the ejection port. Figure 3B It is along Figure 3A The cross-sectional view taken by line A-A' in the diagram. Figure 3C It is along Figure 3A Another cross-sectional view taken from line A-A' in the diagram. Figure 3D This is a schematic diagram showing the ink flow when driving the first energy generating element.

[0047] exist Figures 3A to 3C In this structure, a pressure chamber 12, separated by a partition wall 21 and corresponding to each injection port 11, is formed between the substrate 18 and the perforated plate 19, along with independent flow channels 23 for allowing ink to flow through the pressure chamber 12. The meniscus of the ink extends over the injection port 11, forming the injection port interface as an interface between the ink and the atmosphere.

[0048] The substrate 18 is provided with a first energy generating element 14, which generates energy for ejecting 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 positioned closer to the second supply opening 32 (second opening) than to the first supply opening 22 (first opening). The first energy generating element 14 is driven to generate heat to foam the ink in the pressure chamber 12, and the ink can be ejected from the ejection port 11 by using the foaming energy. The first energy generating element is not limited to the electrothermal conversion element in this example and a piezoelectric element or similar element can be used.

[0049] Furthermore, the substrate 18 is provided with a second energy generating element 24, which generates energy to produce a circulating flow 27 of ink in an independent flow channel, as indicated by the arrow. In this example, an electrothermal conversion element is used. Therefore, the second energy generating element 24 is also referred to as a circulating heater 24.

[0050] The substrate 18 also has an opening for supplying liquid from a common flow channel to an independent flow channel. This opening can be, for example... Figure 3A The configuration shown is as multiple openings (independent supply openings), or it can be as follows: Figure 7AThe supply recess with a single large opening is shown (described later). The second energy generating element 24 is positioned closer to the first supply opening 22 than the second supply opening 32.

[0051] Independent flow channel 23 extends along a second direction, which intersects (in this example, is perpendicular to) the direction in which the injection ports are arranged in rows (the first direction). Independent flow channel 23 includes pressure chamber 12. Figure 3B The inlet (upstream) side of the pressure chamber 12 is connected to the flow channel 13, and... Figure 3B A flow channel on the outlet (downstream) side communicates with the other end portion of the pressure chamber 12. An independent flow channel 23 communicates with a first supply opening 22 and a second supply opening 32 penetrating the substrate 18 at one end on the upstream side and the other end on the downstream side, respectively. Therefore, the connecting flow channel 13 is positioned closer to the second energy generating element than the jet port row. The two end portions of the independent flow channel 23 are located on opposite sides, with the jet port row situated between them. The first supply opening 22 and the second supply opening 32 supply liquid from the common flow channel 38.

[0052] The ink flow in the independent flow channel is generally divided into the following two types: (1) a first ink flow used to drive the first energy generating element 14 and refill after jetting; and (2) a second ink flow used to drive the second energy generating element 24 and form a circulating flow.

[0053] When the first energy generating element 14 is driven to eject liquid from the ejection port 11, ink is supplied according to the ejection from the first supply opening 22 and the second supply opening 32, such as Figure 3D As shown. Therefore, ink flows into the pressure chamber from both supply openings.

[0054] When the second energy generating element 24 is driven to form a circulating flow, ink flows into the independent flow channel 23 through the first supply opening 22 located on the side connected to the flow channel, and flows out to the outside through the second supply opening 32 not located on the side connected to the flow channel. In this example, the ink flowing out from the second supply opening 32 returns to the first supply opening 22 and circulates in the independent flow channel 23 to form the circulating flow 27 indicated by the arrow. Furthermore, in Figure 3B In the configuration shown, the first supply opening 22 and the second supply opening 32 can be shared within the chip. Furthermore, in Figure 3C In the configuration shown, the first supply opening 22 and the second supply opening 32 can be connected to independent flow channels and shared outside the recording nozzle. Either of the above configurations can be used.

[0055] A filter 31 for removing foreign matter from the ink can be installed in the ink circulation channels inside and outside the printhead. Figures 3A to 3DIn this configuration, the filter is positioned outside the independent flow channel, located on both the inflow and outflow sides of the independent flow channel. Furthermore, the filter can be positioned between the first energy-generating element and the second energy-generating element within the independent flow channel. In this case, the filter does not necessarily need to be positioned upstream of the independent flow channel (on the side of the second energy-generating element).

[0056] U-shaped type

[0057] The first embodiment, which will be described later, will be used. Figures 7A to 7C This describes the vicinity of the injection port of a U-shaped liquid jet head. In this specification, "U-shaped" refers to a flow channel in which a first energy generating element (jet energy generating element) and a second energy generating element (flow energy generating element) are formed in a U-shape. That is, in an independent flow channel, the first energy generating element and the second energy generating element are arranged along the injection port row. Furthermore, the independent flow channel is configured such that both end portions are located on one side of the injection port row. Figure 7A This is a plan view observed from the direction of the ejected droplets at the ejection port.

[0058] Figure 7B It is along Figure 7A The cross-sectional view taken from line AB in the diagram. Figure 7C It is shown Figure 7A An enlarged schematic diagram showing the names of the components in the independent flow channel section.

[0059] exist Figures 7A to 7C In this configuration, both the first energy generating element 14 and the second energy generating element 24 are located near the supply groove 42. The independent flow channel 23 is formed in a curved shape (U-shape), such that the first and second energy generating elements are alternately arranged in a row along the injection port direction (first direction) and are interconnected. The independent flow channel 23 includes a pressure chamber 12, Figure 7B The inlet (upstream) side of the pressure chamber 12 is connected to the flow channel 13, and... Figure 7B The outlet (downstream) side flow channel is connected to the other end portion of the pressure chamber 12. The independent flow channel 23 is connected to the supply groove 42 penetrating the substrate 18 on both the upstream and downstream sides. The two end portions of the independent flow channel 23 are positioned adjacent to each other on one side of the supply groove 42.

[0060] Similar to the inline type, the ink flow in the independent flow channel of this type is divided into two types: (1) the first ink flow and (2) the second ink flow.

[0061] When the first energy generating element 14 is driven and liquid is ejected from the injection port 11, ink is supplied from the supply groove 42 according to the injection. Therefore, ink flows into the pressure chamber from both the side connecting the flow channel and the opposite side.

[0062] When the second energy generating element 24 is driven and forms a circulating flow, ink flows from the inlet (upstream) side (which is the side connecting the flow channel) into the independent flow channel 23 and flows out to the outlet (downstream) side. In this example, both flow into and out of the common supply groove 42, thereby forming a circulating flow 27 in the independent flow channel 23 as indicated by the arrow. It should be noted that although shown in this embodiment, the supply groove 42 can be replaced with, for example, Figures 3A to 3D The diagram shows a row of supply openings arranged along the first direction. When the supply recess 42 is replaced with a supply opening, the supply openings are configured to be shared within the chip, as shown. Figure 3B As shown.

[0063] Pump principle

[0064] Figures 4A to 4C This is a schematic diagram illustrating the principle of ink circulation when using a second energy generating element (circulating heater) 24 (which is an electrothermal conversion element). Figure 4A , Figure 4B and Figure 4C Is with Figure 3B Similar cross-sectional views illustrate the generation and growth of bubble B, the contraction of bubble B, and the post-collapse process of bubble B. Bubble B is caused by the film boiling of the ink when the circulating heater 24 heats the ink. Figure 4A In this configuration, the circulating heater 24 is positioned closer to the first supply opening 22 than the second supply opening 32. Therefore, the flow resistance R1 between the circulating heater 24 and the first supply opening 22 is less than the flow resistance R2 between the circulating heater 24 and the second supply opening 32. Figure 4A This includes an equivalent circuit that expresses the flow resistances R1 and R2 as resistors. Due to the difference between the flow resistances R1 and R2, such as Figure 4A As shown, the bubbles B generated by the film boiling of ink tend to grow towards the first supply opening 22, where the flow resistance R1 is smaller. Therefore, in the independent flow channel 23, the ink flow Fa towards the first supply opening 22 is greater than the ink flow Fb towards the second supply opening 32.

[0065] Figure 4B This diagram illustrates the ink flow during the contraction of bubble B. As bubble B contracts, ink flows in to compensate for the shrinkage volume. In this case, as shown... Figure 4BAs shown, the ink flow Fc flowing in from the first supply opening 22 on the side with smaller flow resistance R1 is greater than the ink flow Fd flowing in from the second supply opening 32 on the side with larger flow resistance R2. Furthermore, the location of bubble B collapses from above the circulating heater 24 toward the second supply opening 32.

[0066] Figure 4C This is an illustrative diagram showing the process after bubble B collapses. Because... Figure 4B The Fc>Fd relationship generated in the process produces a circulating flow F of ink from the first supply opening 22 to the second supply opening 32.

[0067] The magnitude of this circulating flow F depends on the ratio of flow resistances R1 and R2 and the size of bubble B. For example, consider the following premise: using a circulating heater 24 as an electrothermal conversion element as a second energy generating element 24. Specifically, it is preferable that the second energy generating element 24 is positioned closer to one of the two end portions of the independent flow channel 23 than the first energy generating element. More specifically, it is preferable to set the flow resistance ratio R1 / R2 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 desirable to increase the flow direction of the circulating flow F. Figure 4A and Figure 4B The ink flow Fa from the first supply opening 22 is shown, and the ink flow Fc flowing in from the first supply opening 22 is increased. Therefore, reducing the flow resistance R1 is effective. Furthermore, it is desirable to minimize the ink flow Fb flowing towards the outflow channel 15 and reduce the ink flow Fd flowing in from the second supply opening 32. Therefore, increasing the flow resistance R2 is effective. Considering the above description, it is desirable to reduce the flow resistance R1 and increase the flow resistance R2, i.e., to reduce the flow resistance ratio R1 / R2. Furthermore, a larger bubble B, i.e., a larger bubble volume, leads to an increase in the volume of the fluid removal space generated from the independent flow channel 23, thereby increasing the circulating flow F.

[0068] Methods for increasing bubble volume include:

[0069] • Increase the size of the circulating heater 24;

[0070] • Reduce flow resistance by increasing the width and height of flow channel 13;

[0071] • Reduce ink viscosity;

[0072] • Increase nozzle temperature;

[0073] • Make the driving pulse a double pulse;

[0074] etc.

[0075] As a portion of the circulating ink 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 channel 13. In this way, by making it less likely for the concentrated ink to remain in the ejection port 11, the influence of the concentrated ink can be prevented. Therefore, the initial inkjet state can be maintained.

[0076] The circulating flow F is a transient flow that occurs during the generation of bubbles B, involving both growth and contraction. Therefore, the inertial flow of bubbles B after collapse weakens over time and eventually ceases. Thus, repeatedly driving the heating element of the circulating heater 24 can be useful in order to stably generate the circulating flow F over a certain period of time. The driving cycle of the circulating heater 24 is not particularly limited, as long as it can discharge the concentrated ink from the ejection port 11. Here, since the circulating flow is transient, involving both growth and contraction during bubble B generation, considering that the period from bubble generation to its collapse is 10 μs (microseconds), driving at a high driving frequency such as 100 kHz (kilohertz) would be less effective. Therefore, it is preferable to drive the circulating heater 24 over a period of, for example, about 100 Hz to tens of kHz. Therefore, the higher the driving frequency, the more stable the circulating flow F is, and the better the discharge of the concentrated ink. On the other hand, it may be useful to consider the increase in ink temperature due to the heat generated by driving the circulating heater 24. Therefore, driving the circulating heater 24 an appropriate number of times may be useful.

[0077] Recycle Concentration

[0078] Figures 5A to 5D and Figures 6A to 6D This is a schematic diagram illustrating the elimination of a concentrated state by using the circulating flow of ink generated by a second energy-generating element. Figures 5A to 5D An inline configuration is shown, in which the inlet and outlet of the circulating flow in the independent flow channel are separate. Figures 6A to 6D A U-shaped configuration is shown, where the inlet and outlet of the circulating flow in independent flow channels are adjacent. The concentrated ink section is shown in dark, and the concentration is indicated by shading.

[0079] First of all, Figures 5A to 5D middle, Figure 5A This illustrates a temporary stop. During the temporary stop, volatile components partially evaporate from the jet port, and the ink condenses near the jet port. Figure 5B The diagram shows the state immediately following the second energy-generating element, after which a circulating flow is generated. This circulating flow eliminates concentration near the ejection port. The ink concentrated near the ejection port is discharged from the outlet, thus eliminating concentration throughout the entire independent flow channel. Figure 5C This indicates a further temporary halt. For example... Figure 5A As shown, the ink is condensed again near the jet port. Figure 5D The state immediately following the cyclic flow generated by the second energy-generating element is shown. (As shown) Figure 5B As shown, the concentration near the injection port is eliminated again, and the concentration throughout the entire independent flow channel is also eliminated. As mentioned above, in the inline type with separate inlet and outlet of the independent flow channel, the concentration state is reset each time the pause and cycle operation is repeated.

[0080] On the other hand, Figures 6A to 6D middle, Figure 6A This indicates a temporary stop. During the temporary stop, the ink condenses near the ejection port, as shown... Figure 5A As shown. Figure 6B The diagram shows the state immediately following the induction of the circulating flow by the second energy-generating element. Here, because the inlet and outlet of the independent flow channel are adjacent, the ink concentrated near the jet port is discharged from the outlet but flows back in from the inlet. Thus, the entire independent flow channel is replaced by slightly concentrated ink instead of fresh ink (hereinafter referred to as recirculation concentration). Figure 6C This indicates a further temporary halt. In this case, besides... Figure 6B In the state shown, the ink is again concentrated near the ejection port, as... Figure 6A As shown. Figure 6D The state shown is the state immediately following the circulation flow generated by the second energy generating element. In this case, as... Figure 6B As shown, due to the effect of recirculation concentration, the entire independent flow channel uses a ratio Figure 6B The ink, now in a more concentrated state, is replaced. As described above, in a U-shaped configuration where the inlet and outlet of an independent flow channel are adjacent, the concentrated state is not reset with each repeated pause and cycle operation, and concentration gradually progresses throughout the independent flow channel, leading to a deterioration in the concentration state. Furthermore, even without repeated cycle operations, the ink can become highly concentrated near the ejection port due to factors such as long stop periods. In this case, even in the first cycle operation, the concentration state is unlikely to improve. This is because the improvement in the concentration state during recirculation concentration is minimal.

[0081] Therefore, there is a difference between the inline type (separate inlet and outlet of the independent flow channel) and the U-shaped type (adjacent inlet and outlet of the independent flow channel) in terms of the elimination of concentration due to the different effects of discharging concentrated ink, resulting from temporary stops and cyclic operations. In the inline type, the concentrated state is easily eliminated throughout the independent flow channel. Therefore, jetting stability is less likely to decrease due to concentrated ink. Conversely, in the U-shaped type, the concentrated state during recirculation concentration is not easily eliminated throughout the independent flow channel. Therefore, jetting is prone to instability due to concentration throughout the independent flow channel.

[0082] ink

[0083] As described above, although the degree of concentration elimination varies depending on the flow channel configuration, the effects of concentrated ink evaporating and thickening at the ejection port can be suppressed by generating ink circulation flow in an independent flow channel using a second energy generating element. In other words, the ink ejection state can be satisfactorily maintained. Therefore, the effects of variations such as ejection speed can be reduced, and ejection is easily stabilized.

[0084] Furthermore, the application of inks with different types of coloring materials and different solid contents is envisioned, depending on the intended use of the liquid jet head and the liquid jetting device on which the head is mounted. That is, regardless of the type of ink used, the performance of the liquid jet head should preferably be able to maintain a high level of jetting stability. For example, to address problems that may be caused by moisture in the ink, such as curling (warping) and wrinkling (wavy wrinkles) on plain paper, inks with reduced water content can be considered. Inks with lower water content contain a high concentration of solids besides water, such as organic solvents, pigments, and resins. Therefore, as the moisture evaporates, a rapid increase in viscosity is likely to occur, which may lead to a decrease in the jetting stability of the ink. For such inks, the method of generating circulating flow in such a pressure chamber as disclosed in this disclosure is very effective because this method can suppress the increase in ink viscosity. Typically, inks with high solid content indicate a solid content of 10 wt%. That is, this disclosure is suitable for application to inks with a solid content of 10 wt% (mass %) or higher.

[0085] Furthermore, by controlling the temperature using heaters located throughout the chip, the printhead's operating temperature can be raised to a constant level. Since ink viscosity varies with temperature, the ink viscosity at the printhead's operating temperature affects jetting stability.

[0086] When a second energy-generating element is used to form a circulating flow, the instantaneous velocity of the circulating flow can range from tens of mm / s to 1000 mm / s. The average velocity observed over a time span on the order of hundreds of microseconds depends on the driving frequency of the circulating heater. This is because the circulating heater generates an instantaneous circulating flow, which decays over time and stops after a certain period. When the second energy-generating element is driven at a frequency of approximately 10 to 20 kHz, the same as the driving frequency (ejection frequency) of the first energy-generating element, the average velocity can range from a few mm / s to 100 mm / s.

[0087] When using inks with high pigment concentrations (e.g., inks with a viscosity of at least 3 cP and no more than 6 cP at printhead operating temperatures), the ink viscosity tends to increase at the ejection port portion depending on the non-ejection period (stop period). Therefore, the ejection rate is prone to variation, and ejection stability is prone to decrease. Thus, it may be useful to circulate the ink during the short stop period, and stable or transient ink circulation at a high frequency may be helpful in eliminating concentration. When the circulation heater is used as a secondary energy-generating element, the ink circulation is transient. Therefore, circulation can be performed at a high frequency, which helps to eliminate concentration at the ejection port portion.

[0088] Conversely, when using inks with lower pigment concentrations (e.g., inks with a viscosity of at least 1 cP and no more than 2 cP at printhead operating temperatures), the inkjet rate can vary depending on the non-printing period (stop period). Here, its effect is relatively small compared to that of high-concentration inks. As the stop period increases, the viscosity of the ink at the ejector port increases depending on the non-printing drive period (off period). Therefore, in order to restart printing after a period of inactivity and stoppage, performing recovery processes associated with waste ink (such as suction operations, wiping operations, and pre-jet preparations combined with them) can be useful. When the circulating heater is used as a secondary energy-generating element, the formation of a circulating flow and the recovery operation help eliminate concentration at the ejector port without generating waste ink. Depending on the off period, waste ink generation can also be prevented by using recovery processes with only circulation operations. Alternatively, recovery processes that minimize the amount of waste ink can be performed by partially combining suction operations for removing air bubbles from the printhead (which are separate from concentration elimination) with recovery through circulation operations.

[0089] Between high-concentration and low-concentration inks, it is desirable to restore the ink to its initial fresh state as much as possible to suppress the effects of concentrated ink. Therefore, even when using a circulating heater as a secondary energy generation element, the lower the impact of recirculation concentration, the better the circulation effect. In other words, an inline configuration is more efficient than a U-shaped configuration.

[0090] First Embodiment

[0091] Figures 7A to 7C These are schematic diagrams showing details near the injection port of the liquid injection head that injects liquid (such as ink) in the first embodiment. Figure 7A This is a plan view observed from the direction of the ejected droplets at the ejection port. Figure 7B It is along Figure 7A The cross-sectional view taken from line AB in the diagram. Figure 7C It is shown Figure 7A An enlarged schematic diagram showing the names of the components in the independent flow channel section. Figure 8 This is a block diagram illustrating the configuration of the selection drive circuitry on the substrate in a comparative configuration. Figure 9 This is a block diagram illustrating the configuration of the selection drive circuit on the substrate in this embodiment.

[0092] exist Figure 7A and Figure 7B In this configuration, a jet port 11 for jetting liquid is formed on an orifice plate 19. A first energy generating element 14 is formed directly below the jet port 11 in a substrate 18. A second energy generating element 24 is formed in the substrate 18 in the same manner as the first energy generating element 14 to create a circulating flow 27 in an independent flow channel 23. Liquid is supplied from a supply groove 42 to the independent flow channel 23 including the jet port 11. In this configuration, the two ends of the independent flow channel are adjacent in a first direction, which is the arrangement direction of the jet port.

[0093] Here, based on Figure 7A In a system with a flow channel shape described as U-shaped, the two ends of the independent flow channels are adjacent in a first direction, which is the arrangement direction of the injection ports. The following will describe... Figure 8 , Figure 9 and Figure 10 The names of the components used. For example... Figure 7C As shown, each independent flow channel 23 is provided with a first energy generating element 14 and a second energy generating element 24. To distinguish these elements, the first energy generating element is represented by Ai (i = 1, 2, 3, ..., n), and the second energy generating element is represented by Bi (i = 1, 2, 3, ..., n). In this case, for example, it indicates that A1 and B1 are located in the same independent flow channel.

[0094] Driver method in comparative configuration

[0095] In comparative configurations, such as Figure 8As shown, a selection drive circuit 200 is formed on substrate 18. A voltage source (+V) and a controller 110 are disposed outside the substrate and connected to the selection drive circuit 200 on the substrate. In response to a control signal received from the control data supply circuit 100 at each address (N1 to N16 in this configuration), an on-off drive circuit (switch) 210 is included, which drives the first energy generating element (A1 to A8) or the second energy generating element (B1 to B8) to turn on or off. That is, the first energy generating element and the second energy generating element are each configured to switch independently between an drivable state and an indrivable state. Here, the control data supply circuit controls the respective drive pulses (P1, P2) 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 at the respective drive timing.

[0096] In the comparative configuration, the first and second energy generating elements are associated with separate addresses and are driven collaboratively in a distributed manner. Using eight first energy generating elements and eight second energy generating elements, as in this comparative configuration, the drive timing is staggered by 16 time divisions, thereby reducing instantaneous power and achieving averaged power. The staggered time for each time division depends on the number of time divisions and the drive frequency, but is on the order of a few μs to 10 μs. With a larger number of energy generating elements, time division blocks are formed in 16 time divisions, and a delay is provided for each time division block. Therefore, the drive timing for energy generating elements with the same number of time divisions differs slightly, except for the 16 time divisions. In this way, instantaneous power can be further reduced and averaged power can be achieved. In this case, the delay time for staggering each time division block is on the order of a few ns, and the staggering gradually increases with the number of time division blocks, but the maximum stagger is approximately several hundred ns to 1000 ns.

[0097] Furthermore, separate drive pulses can be provided for the first energy-generating element used for injection and the second energy-generating element used for circulation. The drive pulses are applied to each energy-generating element at multiple drive timings. In this way, the optimal drive pulse for each energy-generating element can be controlled, and the drive pulses are applied at each drive timing. Alternatively, wiring can be used to apply separate drive pulses to the first and second energy-generating elements. In addition to circuitry for time-division driving based on the total number of energy-generating elements, circuitry can also be provided for staggering the drive timings to impart a delay. Therefore, the circuit size can be increased depending on the type and total number of energy-generating elements.

[0098] The first driving circuit of the embodiment

[0099] In this embodiment, as Figure 9The selection drive circuit 200 shown is formed on the substrate 18. A voltage source and controller 110 are disposed outside the substrate and connected to the selection drive circuit 200 on the substrate. The selection drive circuit 200 includes an on-off drive circuit (switch) 210 that drives each of the first energy generating elements (A1 to A16) and the second energy generating elements (B1 to B16) to turn on or off in response to a control signal received from the control data supply circuit 100 at each address (N1 to N16 in this embodiment). That is, each of the first energy generating elements and the second energy generating elements is independently controlled by a switch configured to switch between an drivable state and an indrivable state.

[0100] Here, the control data supply circuit 100 controls the common drive pulse (P1) driving the first energy generating element or the second energy generating element, and the time interval for applying the common drive pulse to each element during the common drive timing. Here, the first energy generating element and the second energy generating element in the same independent flow channel each have a common drive timing without delay, and are represented by sharing the same address. For example, address N1 corresponds to the set containing the first energy generating element A1 and the second energy generating element B1.

[0101] In this embodiment, by using a common drive pulse for both the first and second energy generating elements, wiring can be shared, and the circuit size for wiring can be reduced. In the first energy generating element used for jetting, the drive significantly affects the printing quality of the output text, images, etc. Therefore, high-precision pulse control can be used. On the other hand, in the second energy generating element used for circulation, slight increases or decreases in the circulation flow rate have almost no impact on printing if circulation occurs. Therefore, high-precision pulse control is not required. For example, when the circulation heater is used as the second energy generating element, circulation occurs if bubbles are generated. Therefore, high-precision pulse control, as required for the first energy generating element, is not necessary.

[0102] Furthermore, in the second energy generating element, the driving energy applied for circulation can be lower than the normal driving energy applied for jetting. For example, when a circulating heater is used as the second energy generating element, circulating flow occurs when bubbles are generated. Therefore, the driving energy may not need to reach the same level as the driving energy of the first energy generating element. Moreover, in jetting heaters, more driving energy than is typically applied to stably generate film boiling and stabilize jetting. Conversely, from the perspective of wanting to generate circulating flow, while bubble generation may be useful, the driving energy can be reduced to some extent. Here, when a heater is used as the energy generating element, it is known that ink kogation based on ink composition accumulates on the heater surface with each drive cycle. This is similar to the case when using a circulating heater as the second energy generating element. When the driving energy is reduced, the excess energy applied to this ink kogation is reduced, and the ink kogation effect is also weakened. Therefore, from this perspective, it is preferable to reduce the driving energy in the circulating heater.

[0103] Next, by setting the first and second energy generating elements in the same independent flow channel to a common, delay-free drive timing, the circuitry required to stagger the drive timings to generate delays and impart drive pulses is halved. Therefore, the circuit size can be reduced accordingly. Since the drive timing is identical and delay-free for both the first and second energy generating elements in the same independent flow channel, if both are selected, they will be driven at exactly the same timing. However, it is not necessary to simultaneously drive the first energy generating element for injection and the second energy generating element for circulation in the same independent flow channel. Therefore, there is no problem with a common drive timing where the elements are driven simultaneously.

[0104] Here, one independent injection unit within the liquid injection head is designated as the first independent injection unit, and another independent injection unit is designated as the second independent injection unit. In this case, the first energy generating element and the second energy generating element within the first independent injection unit are driven at the same timing (the first timing). Furthermore, the first energy generating element and the second energy generating element within the second independent injection unit are driven at the same timing (the second timing). However, the first timing and the second timing do not necessarily have to be the same. By controlling the first timing and the second timing to be different, the power flowing through the circuit can be temporarily reduced. As can be anticipated, the number of independent injection units is not limited to two, and the liquid injection head can have three or more independent injection units.

[0105] In summary, in the first driving circuit of this embodiment, the first energy generating element and the second energy generating element share the driving pulse, and the first energy generating element and the second energy generating element in the same independent flow channel have a common driving timing without delay, thereby reducing the circuit size.

[0106] Furthermore, the first and second energy generating elements do not necessarily have the same size. When the first energy generating element used for injection and the second energy generating element used for circulation use different sized energy generating elements, the aspect ratio of the energy generating elements can be adjusted to use the same drive pulse. Alternatively, when the energy generating element is a heater, the plate resistance value can be changed to use the same drive pulse.

[0107] Furthermore, as described above, it is conceivable that the second energy generating element for circulation has a driving energy lower than the normal driving energy for jetting. In other words, the circulation drive of the second energy generating element can be driven with a lower energy than the jetting drive of the first energy generating element. Even when the driving energy of the second energy generating element is reduced, the size and aspect ratio of the energy generating element can be adjusted accordingly. For example, the size of the second energy generating element can be designed to be smaller than the size of the first energy generating element. Furthermore, for example, when both the first and second energy generating elements are thin-film resistors, the second energy generating element can be designed to be smaller than the first energy generating element in at least one of the longitudinal and transverse dimensions. Furthermore, for example, when both the first and second energy generating elements are thin-film resistors, the sheet resistance value of the second energy generating element can be designed to be smaller than the sheet resistance value of the first energy generating element.

[0108] The second driving circuit of the embodiment

[0109] In the second embodiment, a structure is formed on the substrate 18 as shown in the figure. Figure 10The selection drive circuit 200 is shown. A voltage source and controller 110 are disposed outside the substrate and connected to the selection drive circuit 200 on the substrate. The selection drive circuit 200 includes an on-on driving circuit (a first switch for on-on switching) 230, which turns on and drives a first energy generating element (A1 to A16) or a second energy generating element (B1 to B16) in response to a control signal received from the control data supply circuit 100 at each address (N1 to N16 in this embodiment). That is, the selection drive circuit 200 has a switch configured to be mutually exclusive, such that only one of the first energy generating element and the second energy generating element is in an drivable state. By using such a switch, when the first energy generating element is in an drivable state, the second energy generating element can be in an intoxicable state. Conversely, when the second energy generating element is in an drivable state, the first energy generating element can be in an intoxicable state.

[0110] Here, the control data supply circuit controls the common drive pulse (P1) driving the first energy generating element or the second energy generating element, and the time interval for applying the common drive pulse to each element during the common drive timing. Here, the first energy generating element and the second energy generating element in the same independent flow channel each have a common drive timing and are represented by sharing the same address. For example, address N1 corresponds to the set containing the first energy generating element A1 and the second energy generating element B1.

[0111] Even when the second energy generating element side is selected in the on-off drive circuit 230, the on-off drive circuit (the second switch for on-off switching) 240 for the second energy generating element controls the drive in response to the drive enable-disable signal 300 for the second energy generating element. That is, the switch, configured to switch between an operable state and an inoperable state, further controls the second energy generating element. Therefore, if the first energy generating element is in an inoperable state, the second energy generating element is in an operable state, but it is actually only driven when a drive signal (drive enable-disable signal) indicating that the second energy generating element should be driven is received. If there is no drive enable-disable signal, the second energy generating element will not be driven even when the second energy generating element side is selected in the on-off drive circuit 230. In other words, in this case, neither the first nor the second energy generating element is driven.

[0112] In summary, in the second driving circuit of this embodiment, the driving circuit for controlling the driving of the first energy generating element and the second energy generating element includes: a first switch configured to mutually exclusively switch between the first energy generating element and the second energy generating element, such that only one of them is in a driveable state; and a second switch configured to switch the second energy generating element between a driveable state and a non-driveable state. The driving circuit is characterized in that it is used to drive and control the first energy generating element and the second energy generating element under the following conditions.

[0113] 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 in response to receiving a drive signal instructing the second energy generating element to be driven.

[0114] Furthermore, preferably, 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., located on the electrical downstream side of the second energy generating element. Furthermore, preferably, a common drive signal is used to drive and control the multiple second energy generating elements.

[0115] For comparison, measures to address increased ink viscosity in liquid ejector heads where no circulating flow is formed will be described below. Examples of these measures include a pre-ejection operation to eject ink from the ejection port and a suction operation to draw ink from the ejection port. For example, in a serial liquid ejection apparatus, a pre-ejection or suction operation is performed in the printhead standby area before the protective cover of the printhead is removed and the printing operation begins. Alternatively, a pre-ejection operation is performed in a non-printing area away from the printing medium as the carriage moves back and forth for the printing operation. This operation is performed at a different timing than the printing operation. Furthermore, in cases where ink viscosity tends to increase, a pre-ejection operation can be performed in the printing area during the reciprocating movement, in addition to the printing operation, to a degree that does not affect the image on the printing medium.

[0116] In the second drive circuit of this embodiment, by driving the second energy generating element to perform cyclic operation, the number of pre-jet operations and suction operations can be reduced. In this case, during the reciprocating movement, the timing of the cyclic operation in the printhead standby area or non-printing area is also different from that of the printing operation. Therefore, in the second drive circuit of this embodiment, the driving of the second energy generating element can be easily controlled by the drive enable-disable signal 300 for the second energy generating element. Furthermore, in the case of ink with increasing viscosity, during the cyclic operation in the reciprocating printing area, the timing of the jetting operation can be prioritized in the operation timing close to the printing operation timing. On the other hand, by setting multiple timings for the cyclic operation or setting a certain time period, it is not necessary to drive the cyclic operation and the printing operation simultaneously. Therefore, in the second drive circuit of this embodiment, when the first energy generating element side is selected, the first energy generating element is driven, so that the cyclic operation can be appropriately controlled without affecting the printing operation.

[0117] In summary, in the second drive circuit of this embodiment, similar to the first drive circuit, the drive pulse is shared between the first energy generating element and the second energy generating element, and the drive timing of the first and second energy generating elements in the same independent flow channel is shared to exclusively control the drive timing, thereby reducing the circuit size. Furthermore, the second energy generating element is driven and controlled according to drive data and drive enable / disable signals for the first energy generating element. Therefore, it is not necessary to provide drive data for the second energy generating element. Thus, its advantage lies in a further reduction in circuit size.

[0118] Furthermore, even when multiple second energy generating elements are present, the drive can be controlled based on a common drive enable-disable signal. In addition, in the first and second drive circuits of this embodiment, when n=16, a total of 32 elements (16 pairs) of the first energy generating elements Ai and the second energy generating elements Bi are controlled as a group. For example, the total number of elements in a group can be set to various quantities, such as 16 (8 pairs), 24 (12 pairs), etc.

[0119] In this embodiment, the drive enable-disable signal 300 can be provided to the substrate 18 to control the drive of the second energy generating element, or it can be provided to a liquid jet head outside the substrate or a liquid jetting device outside the liquid jet head to control the drive of the second energy generating element.

[0120] Second Embodiment

[0121] Figures 11A to 11C These are schematic diagrams showing details near the injection port of the liquid injection head that injects liquid (such as ink) in the second embodiment. Figure 11A This is a plan view observed from the direction of the ejected droplets at the ejection port. Figure 11B and Figure 11C It is along Figure 11A Two examples of cross-sectional views taken from line AB in the diagram.

[0122] Here, Figure 11B and Figure 11C Two examples are shown, in which the shape of the rear side of the substrate varies depending on the type of method used to etch the substrate, but the cross-section can have any shape.

[0123] The difference between this embodiment and the first embodiment lies in the inline configuration, in which the inlet and outlet of the independent flow channel are separate. In this embodiment, the two ends of the independent flow channel are separate and positioned at relative positions in a second direction perpendicular to the first direction in which the injection port is arranged.

[0124] The advantages of this configuration are as follows: The inflow and outflow of the circulating flow are separated in opposite directions. Therefore, ink that has become concentrated at the jet port due to circulation will not flow back into the independent flow channel, thus suppressing the effect of concentration.

[0125] Third Embodiment

[0126] Figures 12A to 12C These are schematic diagrams showing details near the injection port of the liquid injection head that injects liquid (such as ink) in the third embodiment. Figure 12A This is a plan view observed from the direction of the ejected droplets at the ejection port. Figure 12B and 12C It is along Figure 12A Two examples of cross-sectional views taken from line AB in the diagram, the two examples being... Figure 11B and Figure 11C similar.

[0127] The differences between this embodiment and the second embodiment are as follows. By providing three rows of supply openings, the number of injection port rows is doubled, and the position of each injection port row is closer to the central supply opening row. That is, injection port rows are formed on both sides of the multiple supply openings along the arrangement direction of the multiple supply openings. Each injection port row can be referred to as the first injection port row and the second injection port row.

[0128] The advantage of this configuration is that by increasing the number of supply openings from two rows to three rows (adding one row), the number of injection port rows can be doubled from one row to two. The two injection port rows can be set offset by a certain pitch, as shown in the figure. Furthermore, it is possible to avoid using wiring areas between the openings in the central supply opening row and to offer greater freedom in the size and resolution of the openings in the central supply opening row. Therefore, high productivity can be easily achieved through rapid nozzle refilling.

[0129] In this embodiment, the three supply opening rows are located at the same position in the direction between the nozzle rows, but each row can be offset depending on the nozzle position and the wiring between the openings. The same configuration can also be applied to the following embodiments.

[0130] Fourth embodiment

[0131] Figure 13A and Figure 13B These are schematic diagrams showing details near the injection port of the liquid injection head that injects liquid (such as ink) in the fourth embodiment. Figure 13A This is a plan view observed from the direction of the ejected droplets at the ejection port. Figure 13B It is along Figure 13A The cross-sectional view taken from line AB in the diagram.

[0132] The differences between this embodiment and the third embodiment are as follows: The direction of the circulating flow is reversed by providing an injection port row on the side closer to the supply opening row on both sides and providing a second energy generating element on the side closer to the center supply opening row.

[0133] The advantages of this configuration are as follows: Ink concentrated near the ejection ports is diverted and discharged to supply openings on both sides, thereby suppressing the effect of concentrated ink when ink re-flows into independent flow channels due to ejection, etc. Furthermore, the ejection port rows are arranged separately from each other, thus suppressing the interference caused by meniscus vibrations resulting from ejection from each ejection port.

[0134] Fifth embodiment

[0135] Figure 14A and Figure 14B These are schematic diagrams showing details near the injection port of the liquid injection head that injects liquid (such as ink) in the fifth embodiment. Figure 14A This is a plan view observed from the direction of the ejected droplets at the ejection port. Figure 14B It is along Figure 14A The cross-sectional view taken from line AB in the diagram.

[0136] The difference between this embodiment and the third embodiment is as follows: The second energy generating element is closer to the first energy generating element, and the second energy generating element is closer to the central supply opening than the supply openings on both sides, thereby reversing the direction of the circulating flow.

[0137] The advantages of this configuration are as follows. Similar to the third embodiment, the central supply opening row offers greater freedom in terms of size and resolution, making it easier to achieve high productivity through rapid refilling. Furthermore, the ink concentrated near the jet port is branched and discharged to the supply opening rows on both sides, thereby suppressing the effect of concentrated ink when ink reflows into independent flow channels due to jetting or other processes.

[0138] Sixth Embodiment

[0139] Figures 15A to 15C These are schematic diagrams showing details near the injection port of the liquid injection head that injects liquid (such as ink) according to the sixth embodiment. Figure 15A This is a plan view observed from the direction of the ejected droplets at the ejection port. Figure 15B and Figure 15C respectively along Figure 15A The cross-sectional view taken from lines A-A' and B-B'.

[0140] The differences between this embodiment and the first embodiment are as follows: The left and right injection ports, interspersed with supply grooves, are arranged in an alternating manner, and a filter is also provided at the inlet of the independent flow channel (near the second energy generating element). Even in this configuration, the effects of this disclosure can be achieved in the same way.

[0141] As stated at the outset, the purpose of this disclosure is to optimize the drive pulse and drive timing to reduce the circuit size in ink-circulating liquid ejector heads that use both jet energy generating elements and flow energy generating elements. To achieve this, in this disclosure, a common drive pulse is used when both the first and second energy generating elements are used. Typically, the jet energy generating element and the flow energy generating element are driven by a single drive pulse. Furthermore, the jet energy generating element and the flow energy generating element in the same circulation path are driven at a common drive timing without delay. Thus, circuit size is suppressed.

[0142] According to this disclosure, in an ink-circulating liquid jet head that uses both a jet energy generating element and a flow energy generating element, the circuit size can be reduced.

[0143] While this disclosure has been described with reference to embodiments, it should be understood that this disclosure is not limited to the disclosed embodiments. The scope of the appended claims is to be given the broadest interpretation in order to cover all such modifications and equivalent structures and functions.

Claims

1. A liquid injection head, comprising: First independent injection unit; Second independent injection unit; and public access routes, The first independent injection unit and the second independent injection unit each include: A jet port configured to jet liquid. The pressure chamber is connected to the injection port. A first energy generating element is disposed in the pressure chamber and configured to generate energy for ejecting the liquid from the injection port. An independent flow channel, which is connected to the pressure chamber, and A second energy generating element is disposed in the independent flow channel. The common flow channel supplies the liquid to the independent flow channels for each of the first and second independent injection units. In each of the first independent injection unit and the second independent injection unit, the first energy generating element and the second energy generating element are driven by a common drive pulse. The first energy generating element and the second energy generating element in the first independent injection unit are driven at the same first timing, which is the first timing. The first and second energy generating elements in the second independent injection unit are driven at a second identical timing, which is the second timing. The first timing and the second timing are controlled to be different from each other.

2. The liquid jet head according to claim 1, wherein the first energy generating element and the second energy generating element are thin-film resistors and differ in at least one of the longitudinal and transverse dimensions.

3. The liquid jet head according to claim 1 or 2, wherein the first energy generating element and the second energy generating element are thin-film resistors and have different sheet resistance values.

4. The liquid jet head according to claim 1 or 2, wherein the second energy generating element performs a circulation drive to circulate the liquid in the independent flow channel, and the first energy generating element performs a jet drive to jet the liquid from the jet port.

5. The liquid jet head according to claim 4, wherein the circulation drive is driven with a weaker energy than the jet drive.

6. The liquid injection head according to claim 1 or 2, wherein the first energy generating element and the second energy generating element belonging to the same independent injection unit are selectively controlled in an exclusive manner so that only one of the first energy generating element and the second energy generating element is driven at the same timing.

7. The liquid injection head according to claim 1 or 2, comprising a plurality of independent injection units, each of the independent injection units comprising the first independent injection unit and the second independent injection unit. The multiple injection ports belonging to the multiple independent injection units form an injection port row.

8. The liquid injection head according to claim 1 or 2, wherein the common flow channel is connected via an opening to a plurality of independent flow channels belonging to the plurality of independent injection units.

9. The liquid injection head according to claim 7, wherein the first energy generating element and the second energy generating element are disposed in the independent flow channel of each independent injection unit along a direction intersecting the injection port row.

10. The liquid jet head of claim 9, wherein the independent flow channel extends in a direction intersecting the jet port array, such that two end portions of the independent flow channel are positioned such that the jet port array is located therebetween.

11. The liquid jet head of claim 10, wherein one end of one of the plurality of independent flow channels of the plurality of independent jet units is connected to the common flow channel through a plurality of first openings arranged along the jet port row, and the other end of the plurality of independent flow channels is connected to the common flow channel through a plurality of second openings arranged along the jet port row.

12. The liquid injection head according to claim 11, wherein, in the arrangement direction of the plurality of second openings, a first injection port row and a second injection port row are formed on both sides of the second opening.

13. The liquid jet head of claim 12, wherein a plurality of the first energy generating elements are positioned closer to the plurality of second openings in the plurality of independent flow channels.

14. The liquid jet head of claim 12, wherein a plurality of the second energy generating elements are positioned closer to the plurality of second openings in the plurality of independent flow channels.

15. The liquid injection head according to claim 7, wherein the first energy generating element and the second energy generating element are arranged in a row along the injection port in at least one of the plurality of independent flow channels.

16. The liquid jet head of claim 15, wherein the independent flow channel is configured such that its two end portions are located on one side of the jet port array.

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