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 that ejects the liquid from the ejection port; a single flow path in communication with the pressure chamber; and a second energy generating element disposed in the single flow path; the common flow path is used for supplying liquid to a single-use flow path of a single-use ejection unit. When the first energy generating element is driven, the second energy generating element is not driven. When the first energy generating element is not driven, the second energy generating element is driven only when a drive command signal for the second energy generating element is received.

Description

Technical Field

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

[0002] A circulating liquid ejection device is known that circulates ink to expel air bubbles in the flow path and prevents an increase in ink viscosity near the nozzle in the liquid ejection head (hereinafter also referred to as the "head"). A known method for ink circulation utilizes a pressure differential (hereinafter also referred to as the "differential pressure method"). This method ensures that the pressure on the ink supply side (inner side) leading to the nozzle is higher than the pressure on the ink recovery side (outer side), causing ink to flow from the inner side to the outer side. To circulate the ink, it is necessary to return the ink that has flowed to the outer side to the inner side, and a pump is required for this purpose. It should be noted that the pump can be located outside the head of the recording device body to circulate the liquid between the liquid ejection head and the body, or the pump can be located inside the liquid ejection head to circulate the liquid within the liquid ejection head. However, this differential pressure circulation method requires mechanisms such as pressure regulating mechanisms and pumps, thus easily increasing the size of the recording device body and head.

[0003] In view of this, ink circulation methods different from differential pressure methods have been studied. Specifically, a mechanism is known that circulates ink in a circulation flow path by providing a circulation flow path in communication with the nozzle, arranging an energy generating element (also called a "flow energy generating element") different from the energy generating element used to eject ink in the circulation flow path (also called an "ejection energy generating element"), and driving the flow energy generating element.

[0004] Japanese Patent Application Publication No. 2020-104312 discloses a structure in which a circulating flow path is arranged, which extends and intersects with a row of nozzles in which a plurality of nozzles are arranged, and a flow energy generating element is disposed in the circulating flow path. Summary of the Invention

[0005] According to some embodiments of this disclosure, a liquid injection head includes a single-use injection unit and a common flow path. The single-use injection unit includes: an injection port for injecting liquid; a pressure chamber communicating with the injection port; a first 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 disposed in the single-use flow path. The common flow path is used to supply liquid to multiple single-use injection units. 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 only after receiving a drive signal for issuing an instruction to drive the second energy generating element.

[0006] The features of this disclosure will become clear 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

[0007] Figure 1A and 1B All are overall views of the device using liquid injection heads.

[0008] Figures 2A to 2D This is an overall view of the liquid jet head and an overall view of the liquid jet chip.

[0009] Figures 3A to 3D This is a schematic diagram of the area near the nozzle of a liquid injection head.

[0010] Figures 4A to 4C This is a schematic diagram of the area near the nozzle of a liquid injection head.

[0011] Figures 5A to 5D This is a schematic diagram of the area near the nozzle of a liquid injection head.

[0012] Figures 6A to 6D This is a schematic diagram of the area near the nozzle of a liquid injection head.

[0013] Figures 7A to 7C This is a schematic diagram of the vicinity of the liquid injection head according to the first embodiment.

[0014] Figure 8 This is a circuit diagram for comparison construction.

[0015] Figure 9 This is a first circuit construction diagram based on the first embodiment.

[0016] Figure 10 This is a second circuit construction diagram based on the first embodiment.

[0017] Figure 11This is a third circuit construction diagram based on the first embodiment.

[0018] Figures 12A to 12C This is a schematic diagram of the area near the nozzle of the liquid injection head according to the second embodiment.

[0019] Figures 13A to 13C This is a schematic diagram of the area near the nozzle of the liquid injection head according to the third embodiment.

[0020] Figure 14A and 14B This is a schematic diagram of the area near the nozzle of the liquid injection head according to the fourth embodiment.

[0021] Figure 15A and 15B This is a schematic diagram of the area near the nozzle of the liquid injection head according to the fifth embodiment.

[0022] Figures 16A to 16C This is a schematic diagram of the area near the nozzle of the liquid injection head according to the sixth embodiment. Detailed Implementation

[0023] 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 subject matter of this disclosure, and not all combinations of features described in the embodiments are necessary for the solutions according to this disclosure. Identical components are denoted by the same reference numerals. In the following description, the basic structure according to this disclosure is first described, followed by the characteristic components according to this disclosure.

[0024] According to the inventors' research, in conventional designs, there is no disclosure regarding the type of drive data used to drive the jet energy generating element and the flow energy generating element. It is generally conceivable to provide drive data to each energy generating element, but the amount of data increases with the number of energy generating elements.

[0025] Therefore, it is advantageous and beneficial to provide a technique for optimizing the amount of drive data in an ink circulating liquid jet head that simultaneously uses jet energy generating elements and flow energy generating elements.

[0026] Liquid injection device

[0027] First, a schematic structure of the liquid injection device 50 in this embodiment is described. Figure 1A and 1B This is an enlarged view of the liquid injection head 1 and its surrounding area of ​​the liquid injection device 50. Figure 1A and 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 liquid ejection device (serial type liquid ejection device) designed to perform image recording by ejecting liquid onto the recording medium P using a liquid ejection head that performs scanning in a direction intersecting with the transport direction of the recording medium P. This disclosure is not limited to serial type liquid ejection devices, but can also be applied to page-width liquid ejection devices (page-width liquid ejection devices perform image recording by ejecting liquid onto the recording medium being transported in the transport direction using a linear head (page-width head) that is longer in the page-width direction of the recording medium). It should be noted that the liquid ejection head in 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 ink that can be ejected from the liquid ejection head is not limited to the above four types of ink. This disclosure can also be applied to liquid ejection heads that eject other types of ink. That is, the type and quantity of ink to be ejected from the liquid ejection head are not limited to any particular type and quantity.

[0028] In the serial liquid jetting apparatus 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 transported by transport rollers (transport devices) 55, 56, 57, and 58 in a secondary scanning direction (Y direction) that intersects (orthogonally in this example) the main scanning direction. In the figures mentioned in the following description, the Z direction represents the vertical direction and intersects (orthogonally in this example) the XY plane defined by the X and Y directions.

[0029] Figure 1A A configuration is shown in which the main ink tank 2, serving as a reservoir, is disposed outside the liquid ejector head. Driven by an external pump 28, the liquid (ink) stored in the ink tank 2 is supplied to the sub-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 where the ink tank 54 is directly positioned above the liquid ejector head 1 (there is no main ink tank 2 serving as a reservoir outside the liquid ejector head). In this configuration, the liquid ejector head 1 and the ink tank 54 are integrated, and in some cases, the liquid ejector head 1 can be attached to and detached from the carriage 60. However, in other cases, the liquid ejector head 1 is integrated with the carriage 60, and only the ink tank 54 can be attached to and detached from the carriage 60. In the following description, the term "ink tank 54" is used... Figure 1A The construction shown is a representative example.

[0030] Liquid injection head 1 includes multiple single-use injection units as described later (see below) Figures 2A to 2DAlthough the specific construction will be described later, the single-use injection unit includes: 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 has a supply flow path for supplying liquid to the single-use flow path in each single-use injection unit.

[0031] When using a liquid ejector head, there is a situation where liquid ejection becomes unstable due to the evaporation of volatile components such as moisture from the ejector or the accompanying concentration of solids near the ejector. Various devices have been designed to prevent this. For example, a cap member (not shown) can be provided in the liquid ejector device at a location along the X-direction away from the recording medium transport path, covering the ejector surface of the liquid ejector head where the ejector nozzles are formed. The cap member is used to cover the ejector surface of the liquid ejector head when no recording operation is performed and to prevent the ejector nozzles from drying out or to protect the ejector nozzles. Furthermore, an ink suction mechanism (not shown) can be provided, in which case the cap member is used to suction ink from the ejector nozzles. When this ink suction operation is performed, the ink near the ejector nozzles is refreshed, and the quality of the obtained image can be maintained. There are also known methods, including methods that discard concentrated ink by performing a jetting called pre-jet (pre-jet) when no recording operation is performed, and methods that perform pre-jet ink in an inconspicuous amount at a location on the recording medium where the image quality is not significant even during recording operation (paper surface pre-jet / in-page pre-jet). While these methods greatly contribute to improving image quality, it is desirable to minimize the amount of waste ink, as some ink is discarded to refresh the nozzle.

[0032] To address this issue, a second energy-generating element (flow energy-generating element) is placed within the single-use flow path, allowing the ink to circulate within the flow path. This reduces waste ink volume while simultaneously decreasing nozzle drying and ink concentration near the nozzle. More specifically, it minimizes the number of pre-jet or suction recovery operations. Furthermore, minimizing the number of pre-jet operations further increases yield and productivity.

[0033] The second energy generating element (flow energy generating element) does not necessarily have to be installed in all single-use injection units of the liquid jet head. Compared to the case where no second energy generating element is installed, the above-mentioned effects can be achieved more effectively when the second energy generating element is installed in some single-use injection units.

[0034] and, Figure 1A The liquid ejector head shown can be configured such that all components corresponding to the four types of ink have a second energy generating element, or only the component corresponding to one type of ink has a second energy generating element. That is, the liquid ejector head can be designed to circulate only at least one type of ink, rather than all four types.

[0035] Basic structure of liquid injection head

[0036] Figure 2A This is an exploded perspective view of the liquid injection head of this embodiment. Figures 2A to 2D As shown, the liquid ejection head includes: a sub-ink tank 54 that temporarily stores ink in the head; and a liquid ejection chip 3 for ejecting ink supplied from the sub-ink tank 54 onto the recording medium P. In this embodiment, the liquid ejection head is fixed and supported on the carriage by a positioning device (not shown) and electrical contacts disposed on the carriage of the liquid ejection device. The liquid ejection head moves along the carriage... Figure 1A and 1B Ink is ejected while the main scanning direction (X direction) is moved as shown, and recording is performed on the recording medium P.

[0037] The external pump 28, connected to the ink tank 2 which serves as the ink supply source, has an ink supply tube 59 (see...). Figure 1A A liquid connector (not shown) is provided at the end of the ink supply tube. When the liquid ejector head 1 is mounted on the liquid ejector device 50, the liquid connector at the end of the ink supply tube 59 is liquid-tightly connected to a liquid connector insertion port, which is a liquid inlet provided in the head housing of the liquid ejector head 1. As a result, 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 of ink tanks 2, external pumps 28, ink supply tubes 59, and sub-ink tanks 54 are provided for the corresponding inks, and the four ink supply paths corresponding to the corresponding inks are formed independently of each other. Thus, the liquid ejector device of this embodiment has an ink supply system that supplies ink from the ink tank 2 provided outside the liquid ejector head 1. It should be noted that the liquid ejector device of this embodiment does not have an ink recovery system for recovering ink from the liquid ejector head and returning the ink to the ink tank. Therefore, the liquid ejector head has a liquid connector insertion port for connecting to the ink supply tube of the ink tank, but does not have a connector insertion port for connecting to the tube for recovering ink from the liquid ejector head and returning the ink to the ink tank. It should be noted that liquid connector insertion ports should be provided for various types of ink.

[0038] Figure 2B , 2C The 2D view is an overall view of the liquid jetting chip that forms the liquid jetting head. Figure 2BThe diagram shows the construction of a chip that sets up four colors. Figure 2C The diagram shows the construction of a single chip for two colors. Figure 2D The diagram illustrates the construction of a chip for each color. Each liquid jet chip has a jet nozzle and pads for electrical packaging. Figure 2A It shows Figure 2B The chip structure shown.

[0039] Figure 2B A first embodiment is shown, in which a chip is formed for four colors. For example, the four colors are black, cyan, magenta, and yellow, forming columns for the corresponding colors, said columns arranged along the Y direction. The nozzles of the corresponding columns are offset from each other in the X direction while being adjacent to each other and arranged at equal intervals in the Y direction. Here, the nozzles in the corresponding columns can be arranged in a row along the Y direction without being offset from each other in the X direction. Alternatively, two columns can be provided for black, for a total of five columns that can be used for the four colors.

[0040] Figure 2C A second embodiment is shown, in which a chip is formed for two colors, and two chips are used. When the two chips are mounted on a liquid spray head, the two chips can be mounted on one liquid spray head, or two liquid spray heads can be prepared, each with a chip mounted thereon.

[0041] Figure 2D A third embodiment is shown, in which one chip is formed for one color, and four chips are used. Like... Figure 2C Similarly, four chips can be mounted on one liquid jet head, or four liquid jet heads can be fabricated, each with a chip mounted on it.

[0042] Moreover, in such Figure 2C and 2D When the chip is divided into multiple chips, all chips do not need to have the same chip length. Furthermore, various combinations of other colors for the chips are also possible, and this also applies when the total number of colors is greater than four.

[0043] Components of the loop unit

[0044] straight

[0045] Figures 3A to 3D This is a schematic diagram illustrating the area near the nozzle of a straight liquid jet head. In this specification, "straight" means that the single-use flow path (where the first energy generating element (jet energy generating element) and the second energy generating element (flow energy generating element) are arranged) has a line intersecting the nozzle (in... Figures 3A to 3DThe first energy generating element and the second energy generating element are arranged in the single-use flow path of the single-use injection unit along a direction intersecting with the nozzle row.

[0046] Figure 3A It is a plan view taken along the direction in which the droplet is ejected from the nozzle. Figure 3B It is along Figure 3A A cross-sectional view of the structure cut by the line A-A' that defines the middle part. Figure 3C It is along Figure 3A Another sectional view of the structure cut by the line A-A' that defines the middle section. Figure 3D This is a view used to illustrate the flow of ink when the first energy generating element is driven.

[0047] exist Figures 3A to 3C In this process, a pressure chamber 12 and a single-use flow path 23 are formed between the substrate 18 and the perforated plate 19. The pressure chamber 12 is separated by a partition wall 21 and corresponds to a corresponding injection port 11. Ink flows through the pressure chamber 12 in the single-use flow path 23. The ink curvature spreads on the injection port 11 and forms an injection port interface, which serves as the interface between the ink and the atmosphere.

[0048] The substrate 18 includes a first energy generating element 14 that generates energy for ejecting ink from the pressure chamber. In this example, an electrothermal conversion element is used. The first energy generating element 14 is positioned closer to the second supply opening 32 (compared to the first supply opening 22) along with the ejection port 11 and the pressure chamber 12. By heating and driving the first energy generating element 14 to cause the ink in the pressure chamber 12 to foam, the foaming energy can be used to eject ink from the ejection port 11. The first energy generating element does not necessarily have to be an electrothermal conversion element as described in this embodiment; a piezoelectric element or the like can be used instead.

[0049] The substrate 18 also includes a second energy generating element 24, which generates energy for generating the circulating flow 27, wherein the ink in the single flow path is 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] Furthermore, the substrate 18 has an opening for supplying liquid from a common flow path to a single-use flow path. This opening can be designed as follows: Figure 3A The diagram shows multiple openings (independent supply openings), or it may be as described below. Figure 7A The supply slot is shown as a large opening. The second energy generating element 24 is positioned closer to the first supply opening 22 (compared to the second supply opening 32).

[0051] Each single-use flow path 23 extends along a second direction that intersects (in this example, is orthogonal) the direction in which the nozzles are aligned (the first direction). Each single-use flow path 23 includes: a pressure chamber 12; Figure 3B The inlet (upstream) side of the flow path 13 is connected to an end portion of the pressure chamber 12; and Figure 3B The outlet (downstream) side flow path communicates with the other end portion of the pressure chamber 12. A single-use flow path 23 communicates with a first supply opening 22 and a second supply opening 32, which pass through the substrate 18 at one end on the upstream side and the other end on the downstream side, respectively. Therefore, the connecting flow path 13 is located closer to the second energy generating element (compared to the injection port row). The two end portions of each single-use flow path 23 are located on opposite sides of each other, with the injection port row positioned between these two end portions. Liquid is supplied to the first supply opening 22 and the second supply opening 32 from a common flow path 38.

[0052] The ink flow through each single-use flow path is divided into two: (1) a first ink flow for driving the first energy generating element 14 and performing refill after ejection; and (2) a second ink flow for driving the second energy generating element 24 and forming a circulating flow.

[0053] When the first energy generating element 14 is driven and liquid is ejected from the ejector port 11, ink flows into the pressure chamber from both the first supply opening 22 and the second supply opening 32, so that ink is supplied from the first supply opening 22 and the second supply opening 32 as the liquid is ejected. Figure 3D As shown.

[0054] 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 opening 22 on the connected flow path side and flows out through the second supply opening 32, which is not on the connected flow path side. In this example, the ink that has flowed out from the second supply opening 32 returns to the first supply opening 22 and circulates, so as to form a circulating flow 27, as indicated by the arrow, in the single-use flow path 23. It should be noted that... Figure 3B A configuration is shown in which a first supply opening 22 and a second supply opening 32 are integrated into the chip. Furthermore, in Figure 3C One configuration is shown in which a first supply opening 22 and a second supply opening 32 are connected to a single-use flow path and integrated outside the recording head; any of these configurations can be used.

[0055] A filter 31 for removing foreign matter from the ink can be disposed in the ink circulation flow path inside and outside the recording head 20. In Figure 3, the filter is arranged on the inflow side and the outflow side, which are located outside the single-use flow path. Moreover, the filter can be disposed between the first energy generating element and the second energy generating element in the single-use flow path. In this case, the filter may not be disposed on the upstream side (second energy generating element side) which is the outer side of the single-use flow path.

[0056] U-shaped type

[0057] Now referring to the first embodiment described later. Figures 7A to 7C This describes the vicinity of the nozzle of a U-shaped liquid jet head. In this specification, "U-shaped" means that the flow path in which the first energy generating element (jet energy generating element) and the second energy generating element (flow energy generating element) are arranged has a U-shape. That is, in a single-use flow path, the first energy generating element and the second energy generating element are arranged along the nozzle row. Furthermore, the single-use flow path is designed such that either end portion of it is located on one side relative to the nozzle row. Figure 7A It is a plan view taken along the direction in which the droplet is ejected from the nozzle. Figure 7B It is along Figure 7A A cross-sectional view of the structure cut by the line AB that defines the middle part. Figure 7C It is used for explanation Figure 7A An enlarged schematic diagram of the component names in the single-flow path section.

[0058] 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 tank 42. The flow path 23 is formed in a U-shape, wherein the first and second energy generating elements are arranged alternately in a row along the nozzle in a first direction, and the shape is curved to connect them. Each flow path 23 includes a pressure chamber 12. Figure 7B The inlet (upstream) side of the flow path 13 is connected to one end portion of the pressure chamber 12; and Figure 7B The downstream flow path in the pressure chamber 12 communicates with the other end portion of the pressure chamber 12. The single-use flow path 23 communicates with the supply channel 42 passing through the substrate 18 on both the upstream and downstream sides. The two end portions of each single-use flow path 23 are positioned adjacent to each other on one side of the supply channel 42.

[0059] The ink flow in a single flow path is classified into two types, namely, (1) the first ink flow and (2) the second ink flow, as in the straight type.

[0060] When the first energy generating element 14 is driven and liquid is ejected from the injection port 11, ink is supplied from the supply tank 42 along with the ejection, so that ink flows into the pressure chamber from both sides of the flow path side and the opposite side.

[0061] When the second energy generating element 24 is driven to form a circulating flow, ink flows into the single-use flow path 23 from the inlet (upstream) side, which serves as the connecting flow path side, and flows out towards the outlet (downstream) side. In this example, the two flows into and out of the common supply tank 42 form a circulating flow 27, as indicated by the arrow in the single-use flow path 23. Although the supply tank 42 is shown in this embodiment, it can be replaced by a row of supply openings arranged along the first direction, such as... Figures 3A to 3D As shown. When the supply slot is replaced by a supply opening, the supply opening is integrated into the chip, as... Figure 3B As shown.

[0062] Pump principle

[0063] Figures 4A to 4C This is a schematic diagram illustrating the principle of generating ink circulation flow when using a second energy generating element (circulating heater) 24 as an electrothermal conversion element. Figure 4A , Figure 4B and Figure 4C They are all similar Figure 3B The cross-sectional view shows the process of bubble B being generated and grown due to film boiling of the ink after it is heated by the circulating heater 24, the shrinkage process, and the post-defoaming process. Figure 4A In this configuration, the circulating heater 24 is positioned closer to the first supply opening 22 (compared to the second supply opening 32). Therefore, the flow resistance R1 between the circulating heater 24 and the first supply opening 22 is lower than the flow resistance R2 between the circulating heater 24 and the second supply opening 32. Figure 4A The structure in the diagram is an equivalent circuit combination where the flow resistances R1 and R2 are represented as resistors. Due to the difference between the flow resistances R1 and R2, such as... Figure 4A As shown, bubbles B generated by the film boiling of ink grow on the side of the first supply opening 22, which has low flow resistance R1. Therefore, in the single-use flow path 23, the ink flow Fa toward the first supply opening 22 is greater than the ink flow Fb toward the outflow path 15.

[0064] 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. At this time, the ink flow Fc from the first supply opening 22 on the low flow resistance R1 side is greater than the ink flow Fd from the second supply opening 32 on the high flow resistance R2 side, as shown below. Figure 4B As shown. Moreover, bubble B disappears from a position closer to the second supply opening 32 above the circulating heater 24.

[0065] Figure 4C This is an explanatory diagram showing the process after bubble B defoams. In Figure 4B The relationship Fc>Fd generated in the process results in a circulating flow F of ink from the first supply opening 22 toward the second supply opening 32.

[0066] The magnitude of the circulating flow F is influenced by the ratio between the flow resistances R1 and R2, as well as the size of the bubble B. For example, assuming that the circulating heater 24, as an electrothermal conversion element, is used as a second energy generating element 24, it is preferable that the second energy generating element 24 is positioned closer to one of the two end portions of the 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. When the flow resistance ratio R1 / R2 is set within this range, the circulating flow F can be maximized. It is important to ensure that the circulating flow F has a larger ink flow Fa flowing toward the first supply opening 22, and a smaller ink flow Fc flowing in from the first supply opening 22. Figure 4A and 4B (As shown). Therefore, reducing the flow resistance R1 is effective. Furthermore, it is important to minimize the ink flow Fb flowing towards the outflow path 15 and reduce the ink flow Fd flowing in from the second supply opening 32. Therefore, increasing the flow resistance R2 is effective. Given the above, it is important to reduce the flow resistance R1 and increase the flow resistance R2, or to decrease the flow resistance ratio R1 / R2. Moreover, large bubbles B or large bubble volumes lead to an increase in the repulsive volume of the fluid generated in the single-use flow path 23, and thus result in a larger circulating flow F.

[0067] The methods to increase bubble volume include the following:

[0068] -Increase the size of the circulating heater 24

[0069] - Reduce flow resistance by increasing the width and height of flow path 13

[0070] - Reduce ink viscosity

[0071] -Increase head temperature

[0072] - Dual-pulse driving pulse.

[0073] A portion of the circulating ink flow F enters the ejector 11 to deliver the concentrated ink in the ejector 11 to the second supply opening 32 side, and fresh ink is introduced into the ejector 11 from the first supply opening 22 side via the connecting flow path 13. By making it less likely that the concentrated ink will remain in the ejector 11 in this way, the influence of the concentrated ink can be reduced and the initial ink ejection state can be maintained.

[0074] When bubble B is generated, the circulating flow F is a transient flow accompanied by growth and contraction processes. Therefore, the inertial flow of bubble B after defoaming weakens over time and stops after a certain period. Therefore, to stably generate the circulating flow F within a certain time period, the heating element of the circulating heater 24 can be repeatedly driven. The driving cycle of the circulating heater 24 is not limited to any specific cycle, as long as the concentrated ink in the nozzle 11 can be discharged. However, since the flow is a transient flow accompanied by growth and contraction processes when bubble B is generated, the effect is relatively small when driving at a high driving frequency, for example, 100 kHz, considering the 10 μs cycle (the time from bubble generation to defoaming). Therefore, it is preferable to drive the circulating heater 24 at a cycle, for example, approximately 100 Hz to tens of kHz; the higher the driving frequency, the more effectively the circulating flow F can be maintained. Therefore, the effect of discharging concentrated ink is enhanced. On the other hand, the temperature rise of the ink due to the heat generated by driving the circulating heater 24 can be considered. Therefore, the number of times the circulating heater 24 is driven can be appropriately controlled.

[0075] It should be noted that it is conceivable that the second energy-generating element, which contributes to the circulation, has a lower driving energy than the normal driving energy used to perform the injection drive. In other words, the circulation drive of the second energy-generating element can be performed with a weaker energy than the injection drive of the first energy-generating element. With the driving energy for the second energy-generating element reduced, the size and aspect ratio of the energy-generating element can be adjusted accordingly.

[0076] Recycle Concentration

[0077] Figures 5A to 5D and Figures 6A to 6D This is a schematic diagram illustrating the elimination and concentration of ink circulating flow caused by the second energy generating element. Figures 5A to 5D A straight configuration is shown, in which the inlet and outlet of the circulating flow in a single flow path are separated from each other. Figures 6A to 6D The diagram shows a U-shaped structure where the inlet and outlet of the circulating flow in the single-flow path are adjacent to each other. It should be noted that areas where the ink has become concentrated are represented as darker shades, and the degree of concentration is indicated by color grayscale.

[0078] First of all, Figures 5A to 5D middle, Figure 5A The paused state is shown. During the pause, volatile components evaporate from the nozzle portion, and ink concentration occurs near the nozzle. Figure 5B The diagram shows the state immediately following the circulation flow generated by the second energy-generating element. Concentration near the nozzle is eliminated by the circulation flow. The ink concentrated near the nozzle is discharged through the outlet, and concentration is eliminated throughout the entire single-use flow path. Figure 5CThe image shows another pause state after this. Ink concentration is performed again near the nozzle, as... Figure 5A As shown. Figure 5D The diagram shows the state immediately after the circulating flow is regenerated by the second energy-generating element. Concentration near the nozzle is eliminated again, as is concentration throughout the single-use flow path, such as... Figure 5B As shown above, in a straight configuration where the inlet and outlet of a single flow path are separated, the concentration state is reset each time the pause and cycle operation is repeated.

[0079] On the other hand, Figures 6A to 6D middle, Figure 6A The paused state is shown. During the pause, ink concentration occurs near the nozzle, such as... Figure 5A As shown. Figure 6B The diagram shows the state immediately following the generation of the circulating flow by the second energy-generating element. Because the inlet and outlet of the single-use flow path are adjacent to each other, the ink concentrated near the nozzle is discharged through the outlet but flows back in through the inlet. This utilizes slightly concentrated ink instead of fresh ink to replace the ink throughout the single-use flow path (this will be referred to below as recirculation concentration). Figure 6C This indicates another pause state that follows. At this point, besides... Figure 6B In addition to the conditions shown, ink concentration again occurs near the nozzle, as referenced above. Figure 6A As stated above. Figure 6D The image shows the state immediately after the second energy-generating element re-establishes the circulating flow. At this point, due to the effect of recirculation and concentration, the ink concentration in the entire single-use flow path increases by a certain percentage. Figure 6B Replace with even more concentrated ink, as referenced above. Figure 6B As described above, in a U-shaped configuration where the inlet and outlet of a single-use flow path are adjacent to each other, the concentration state is not reset with each repeated pause and cycle operation. Instead, concentration gradually occurs throughout the single-use flow path, and the concentration state deteriorates. Here, even without repeated cycle operations, if the ink near the nozzle is greatly concentrated due to a long pause time, the concentration state is hardly reduced even with the first cycle operation. This is because recirculation concentration is almost ineffective in reducing the concentration state.

[0080] Therefore, between a straight configuration where the inlet and outlet of the single-use flow path are separate, and a U-shaped configuration where the inlet and outlet of the single-use flow path are adjacent, there are differences in the concentration elimination state caused by pauses and recirculation operations due to the different effects of the discharged concentrated ink. In the straight configuration, the concentration state throughout the single-use flow path is easily eliminated, so the jetting stability is hardly degraded by the concentrated ink. On the other hand, in the U-shaped configuration, due to recirculation concentration, it is difficult to eliminate the concentration state throughout the single-use flow path, so jetting may become unstable depending on the concentration throughout the single-use flow path.

[0081] ink

[0082] As mentioned earlier, the degree of concentration elimination varies depending on the flow path construction. However, by utilizing a second energy-generating element to generate an ink circulation flow in a single-use flow path, the influence of concentrated ink (whose viscosity increases due to evaporation at the nozzle) can be reduced. In other words, since the ink ejection state can be well maintained, the effects of variations in ejection speed, etc., can be reduced, and ejection becomes easier to stabilize.

[0083] On the other hand, it is assumed that inks with different types of color materials or different solid contents are used depending on the intended use of the liquid jet head and the liquid jetting device equipped with the head. That is, it is preferable that the liquid jet head maintains a high level of jetting stability even when using any type of ink. For example, it is conceivable to use inks with reduced moisture content to combat problems that may occur due to moisture in the ink, such as curling (warping) and wrinkling (wavy creases) in ordinary paper. Since the concentration of solids (e.g., organic solvents, pigments, and resins) other than water becomes higher in inks with low moisture content, the viscosity of the ink tends to increase rapidly with the evaporation of moisture, resulting in reduced ink jetting stability. For such inks, the method of generating a circulating flow in a pressure chamber, as described in this disclosure, is particularly effective because it reduces the increase in ink viscosity. Typically, inks with high solid content have a solid content of 10% by weight. That is, this disclosure is preferably applied to inks with a solid content of 10% by weight (mass%) or more.

[0084] Furthermore, regarding the temperature during head operation, the head can be used at a constant temperature by arranging and controlling heaters throughout the chip. Since ink viscosity varies with temperature, the ink viscosity at the head operating temperature affects jetting stability.

[0085] When a circulating flow is formed by a second energy-generating element, the instantaneous velocity of the circulating flow can range from tens of mm / s to 1000 mm / s. In a time span of approximately several hundred microseconds, the average velocity depends on the driving frequency of the circulating heater. This is because, in the case of a circulating heater, the circulating flow is an instantaneous flow that decays over time and stops after a certain period. When the drive is performed at a frequency of approximately 10 to 20 kHz (which is almost the same as the driving frequency (ejection frequency) of the first energy-generating element), the average velocity can range from several mm / s to 100 mm / s.

[0086] 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 the head operating temperature), the ink viscosity tends to increase at the nozzle portion, depending on the non-jetting time (pause time). Therefore, the jetting speed may vary, and jetting stability may decrease. In view of this, ink circulation can be performed during short pause times, and concentration can be eliminated by performing stable ink circulation at a high frequency or by short-duration ink circulation. In the case where the circulation heater is used as a secondary energy generating element, short-duration ink circulation is performed. Therefore, circulation is performed at a high frequency to help eliminate concentration at the nozzle portion.

[0087] On the other hand, when using inks with low pigment concentrations (e.g., inks with a concentration such that the viscosity at the head operating temperature is at least 1 cP and no more than 2 cP), for example, the jetting speed may vary depending on the non-jetting time (pause time), but its effect is relatively small compared to high-concentration inks. With long pause times, the ink viscosity becomes higher at the nozzle portion, for example, depending on the non-printing drive time (stop time). Therefore, upon restarting after a stop (after a period of no printing), waste ink recovery processes can be performed, such as suction operations, wiping operations, and pre-jetting combined with these operations. When a circulating heater is used as a second energy-generating element, a circulating flow is formed, and the recovery operation is performed. Therefore, it can help eliminate concentration at the nozzle portion without generating any waste ink. Depending on the stop time, it can also prevent waste ink generation through recovery processes involving only circulation operations. Alternatively, recovery processes can be performed by partially combining suction operations (for removing air bubbles in the head rather than for eliminating concentration) while performing recovery through circulation operations, so as to minimize waste ink.

[0088] The goal is to return both high-concentration and low-concentration inks to their initial fresh state as much as possible to minimize the impact of concentrated ink. Therefore, even when the circulating heater is used as a secondary energy-generating element, a greater circulation effect can be achieved when the effect of the recirculated concentration is smaller. In other words, the straight configuration provides a greater effect than the U-shaped configuration.

[0089] First Embodiment

[0090] Figures 7A to 7C This is a schematic diagram illustrating the vicinity of the nozzle of a liquid jet head that jets a liquid, such as ink, in the first embodiment. Figure 7A It is a plan view taken along the direction in which the droplet is ejected from the nozzle. Figure 7B It is along Figure 7A A cross-sectional view of the structure cut by the line AB that defines the middle part. Figure 7C It is used for explanation Figure 7A An enlarged schematic diagram of the component names in the single-flow path section. Figure 8 This is a block diagram illustrating the construction of the selection drive circuit on the substrate in a comparison configuration. Figure 9 This is a block diagram illustrating the construction of the selection drive circuit on the substrate in this embodiment.

[0091] exist Figure 7A and 7B In this configuration, a nozzle 11 for spraying liquid is formed in an orifice plate 19. A first energy generating element 14 is formed in a substrate 18 directly below the nozzle 11. In addition to the first energy generating element 14, a second energy generating element 24 is formed in the substrate 18 in a similar manner, and a circulating flow 27 is formed in a single-use flow path 23. Liquid is supplied from a supply tank 42 to the single-use flow path 23, which includes the nozzle 11. At this time, the two ends of the single-use flow path are adjacent to each other along a first direction in which the nozzle is arranged.

[0092] Here, because Figure 7A In a system where the flow path shape is described as a U-shaped configuration, the two ends of the flow path are adjacent to each other along a first direction in which the injection nozzles are arranged. The following describes... Figure 8 and Figure 9 The names of the corresponding components used. For example... Figure 7C As shown, each single-use flow path 23 includes a first energy generating element 14 and a second energy generating element 24. To distinguish the 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, A1 and B1 represent corresponding elements in the same single-use flow path.

[0093] Driving methods for comparison construction

[0094] In comparative constructions, such as Figure 8The selection drive circuit 200 shown is formed on the substrate 18. A voltage source (+V) and a controller 110, which serves as a control unit, are disposed outside the substrate and connected to the selection drive circuit 200 on the substrate 18. The selection drive circuit 200 includes an on-off drive circuit (on-off changeover switch) 210.

[0095] The on-off drive circuit 210 drives each of the first energy generating elements (A1 to A8) or the second energy generating elements (B1 to B8) to an on or off state in response to control signals received from the control data supply circuit 100 at each address (N1 to N16 in this configuration). That is, each of the first and second energy generating elements is independently controlled by a switch designed to switch between an drivable state and an indrivable state. Here, the control data supply circuit 100 controls the drive pulses used to drive the first or second energy generating elements and the time interval between the drive pulses applied to each element.

[0096] In the comparison configuration, the first energy generating element and the second energy generating element are associated with different addresses and are provided with separate drive circuits. Therefore, drive data can be provided for each of the first and second energy generating elements. Consequently, the amount of data increases with the total number of elements that are first and second energy generating elements.

[0097] First driving method of the embodiment

[0098] In the first driver construction of this embodiment, as follows Figure 9 The selection drive circuit 200 shown is formed on the 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 18. The selection drive circuit 200 includes an on-off drive circuit 230 (a first switch for performing on-off switching).

[0099] The turn-on drive circuit 230 responds to control signals received from the control data supply circuit 100 at each address (N1 to N16 in this embodiment) to turn on and drive one of the first energy generating elements (A1 to A16) and the second energy generating element (B1 to B16). That is, the turn-on drive circuit 230 includes a switch designed to exclusively switch the first and second energy generating elements, such that only one of them is in an actuated state. Through this switch, when the first energy generating element is in an actuated state, the second energy generating element is always in an inoperable state. Conversely, when the second energy generating element is in an actuated state, the first energy generating element is always in an inoperable state.

[0100] Here, the control data supply circuit 100 controls the drive pulses used to drive the first energy generating element or the second energy generating element, as well as the time interval between the drive pulses being applied to each element.

[0101] In the accompanying drawings, the first energy generating element group 401 and the second energy generating element group 402 collectively represent the first energy generating element 14 and the second energy generating element 24, respectively. Reference numerals 401A and 401B denote different first energy generating element groups 401. Reference numerals 402A and 402B denote different second energy generating element groups 402. Furthermore, in the accompanying drawings, for example, "14-A1" represents "first energy generating element A1," and "24-B1" represents "second energy generating element B1."

[0102] The selection drive circuit 200 also includes an on / off drive circuit 240 for the second energy generating element (a second switch for performing on / off switching). Even when the second energy generating element side is selected by the on / off drive circuit 230, the on / off drive circuit 240 controls the drive of the second energy generating element according to the drive enable / disable signal 300 for the second energy generating element. That is, the second energy generating element is further controlled by a switch designed to switch the second energy generating element between an drivable state and an indrivable state.

[0103] Therefore, while the first energy generating element is in an inoperable state, the second energy generating element is in an operable state, but it is only actually driven when a drive signal (drive enable / disable signal) instructs it to drive the second energy generating element. If no drive enable / disable signal is received, even if the on-off drive circuit 230 selects the second energy generating element side, no second energy generating element is driven. That is, at this time, neither the first nor the second energy generating element is driven. Here, as the first drive circuit in this embodiment, the common drive enable / disable signal is used for all second energy generating elements.

[0104] In summary, in this embodiment, the drive circuit for controlling the driving of the first energy generating element and the second energy generating element includes: a first switch designed to exclusively switch the first energy generating element and the second energy generating element, such that only one element enters an drivable state; and a second switch designed to allow the second energy generating element to switch between an drivable state and an indrivable state. When the drive circuit is used, the first energy generating element and the second energy generating element are characteristically driven and controlled under the following conditions:

[0105] Condition: When the first energy generating element is driven, the second energy generating element is not driven. When the first energy generating element is not driven, the second energy generating element is driven when a drive signal for issuing a command to drive the second energy generating element is received.

[0106] Furthermore, it is preferable that the on-off drive circuit (second switch) is arranged closer to the second energy generating element than the on-off drive circuit (first switch), and is electrically arranged on the downstream side relative to the second energy generating element. It is also preferable to use a common drive signal to drive and control multiple second energy generating elements.

[0107] In comparison, this article describes measures to address the increased ink viscosity in liquid ejector heads that do not form a circulating flow. These measures include pre-ejection operations for ejecting ink through the nozzle and suction operations for drawing ink from the nozzle. For example, in a serial liquid ejector device, a pre-ejection or suction operation is performed before the device moves away from the cap (which protects the head in a standby position) to the printing operation. Alternatively, a pre-ejection operation is performed in a non-printing area outside the printing media during reciprocating movement via the carriage in the printing operation. These are timings different from those during the printing operation. Moreover, in the case of inks that readily increase viscosity, a pre-ejection operation can be performed in addition to the printing operation so that no image interference occurs on the printing media in the printing area during reciprocating movement.

[0108] In this embodiment, by driving the second energy generating element to perform the cyclic operation, the number of pre-jet or suction operations can be reduced. In this case, the timing of the cyclic operation in the non-printing area during the head standby position or reciprocating movement is also different from the timing of the printing operation. Therefore, in 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. When the ink has a viscosity that easily increases, during the cyclic operation in the reciprocating printing area, the jetting operation can be prioritized at a timing close to the printing operation. On the other hand, multiple timings for the cyclic operation, or a certain time period for the cyclic operation, can be set to eliminate the need to perform the cyclic operation and the printing operation simultaneously. Therefore, in this embodiment, the first energy generating element is driven when the first energy generating element side is selected. Therefore, the cyclic operation can be appropriately controlled without affecting the printing operation.

[0109] As described above, the second energy generating element is driven and controlled based on the drive data and drive enable / disable signals for the first energy generating element. This eliminates the need to provide drive data for the second energy generating element, resulting in the advantage of being able to correspondingly reduce the amount of drive data.

[0110] Furthermore, in the case of multiple second energy generating elements, drive control can be performed based on a common drive enable / disable signal. In this embodiment, the first energy generating element Ai and the second energy generating element Bi are controlled as a group of a total of 32 elements (16 pairs), where n is at most 16. However, the total number of elements in a group can be any suitable value, such as 16 (eight pairs) or 24 (12 pairs).

[0111] Although an electrothermal conversion element or a piezoelectric element can be used as a second energy generating element, this embodiment describes the direction of the circulating flow in the case of an electrothermal conversion element. In the case of a piezoelectric element, the circulating flow may be opposite to that of the above embodiment, depending on the driving method.

[0112] In this embodiment, a drive enable / disable signal 300 is provided in the substrate 18 to control the drive of the second energy generating element. However, the drive enable / disable signal 300 may be provided in a liquid jet head outside the substrate, or in a liquid jetting device outside the liquid jet head, to control the drive of the second energy generating element.

[0113] Second driving method of the embodiment

[0114] Figure 10 This is a block diagram illustrating the construction of the selection drive circuit on the substrate in the second drive structure of this embodiment. Here, multiple single-use jetting unit groups are proposed. Each single-use jetting unit group includes multiple single-use jetting units. According to the drive signal, instructions are issued to each single-use jetting unit group for the second energy generating element 24.

[0115] The difference between this embodiment and the first driving method is that multiple common drive enable / disable signals 300 are set as the first drive enable / disable signal 301 and the second drive enable / disable signal 302. In this embodiment, multiple drive enable / disable signals are provided for each array. Here, the first energy generating element group 401 and the second energy generating element group 402 represent different rows. It should be noted that the number of arrays can be applied to multiple rows including two or more rows. Each first energy generating element group 401 and second energy generating element group 402 is an energy generating element group included in multiple single-use injection units arranged along the array direction.

[0116] The advantages of this configuration include instantaneous power reduction and power averaging by reducing the total number of second energy-generating elements to be driven. Here, the second energy-generating elements are controlled by a common drive enable / disable signal using a first driving method. When the common drive enable / disable signal is received, all the first energy-generating elements are driven even if not all of them are, thus all the second energy-generating elements are driven. In this way, the number of second energy-generating elements to be driven increases accordingly, even when the first energy-generating elements are driven almost entirely, which utilizes more electrical power.

[0117] On the other hand, by providing multiple drive enable / disable signals to each column using the second driving method, the number of second energy generating elements can be reduced. Here, in particular, during cyclic operations using the second energy generating elements in non-printing areas, electrical power is used because the first energy generating elements are not driven. Furthermore, because the timing differs from that used for printing operations, electrical power is allocated to operations other than printing, such as paper feeding. Therefore, there are different power constraints compared to the printing area, requiring power reduction. Therefore, providing drive enable / disable signals to each row reduces the number of second energy generating elements to be driven, thus enabling instantaneous power reduction and power averaging.

[0118] This also applies to situations where multiple colors are provided within the same chip, and where drive enable / disable signals are provided for each color (rather than each row). When providing multiple inks of the same color, such as pigment inks and dye inks, these inks are distinguished as different colors, and drive enable / disable signals are provided for each color. When providing drive enable / disable signals for each color, power consumption can be reduced as in the case of providing drive enable / disable signals for each row. Furthermore, when only specific colors are used, such as in black and white printing mode, power consumption can be reduced by providing drive enable / disable signals only for that specific color ink.

[0119] It should be noted that when a drive enable / deactivation signal for the corresponding row or color is generated, multiple drive enable / deactivation signals can be supplied from outside the chip, or the signal can be divided into multiple signals within the chip.

[0120] The third driving method in the embodiment

[0121] Figure 11 This is a block diagram illustrating the construction of the selection drive circuit on the substrate in the third drive structure of this embodiment. Multiple single-use injection unit groups are also presented here.

[0122] This method differs from the first and second driving methods in that it provides multiple drive enable / deactivation signals 301 and 302 for corresponding rows as row-specific drive enable / deactivation signals 301A, ... and 302A, ... . In this way, multiple drive enable / deactivation signals are provided for each block in the row. It should be noted that this also applies to multiple rows in which drive enable / deactivation signals are provided for corresponding blocks among multiple blocks.

[0123] The advantages of this configuration include instantaneous power reduction and power averaging by further reducing the total number of second energy-generating elements to be driven. In particular, when the first energy-generating elements are driven almost or not at all in non-printing areas, the number of second energy-generating elements to be driven can be reduced, as in the case of the second driving method. The electrical power can be further reduced due to the drive enable / disable signal for the corresponding block (rather than the drive enable / disable signal for the corresponding line). Moreover, when a portion (rather than the entire line) of a line is a non-printing area, the electrical power used for the corresponding second energy-generating element can be reduced accordingly. For example, in a serial liquid jet apparatus, a portion of a line may be a non-printing area in the initial scan at the start of printing on the recording medium or in the final scan at the end of printing. When performing a cyclic operation using the second energy-generating elements for each scan operation, the electrical power can be reduced accordingly. Furthermore, in a page-width liquid jet apparatus, the print width varies with the print size; therefore, a portion of a line may be a non-printing area. In this case, printing can be performed without performing a cyclic operation using the second energy-generating elements, thus reducing the electrical power accordingly.

[0124] Second Embodiment

[0125] Figures 12A to 12C This is a schematic diagram illustrating the area near the nozzle of a liquid jet head that jets a liquid, such as ink, in the second embodiment. Figure 12A It is a plan view taken along the direction in which the droplet is ejected from the nozzle. Figure 12B and Figure 12C It is along Figure 12A Two examples of sectional views taken by the defined line AB.

[0126] here, Figure 12B and 12C Two examples are shown, in which the shape of the back side of the substrate varies depending on the type of etching method used on the substrate, and the back side of the substrate can have any shape as its cross-sectional shape.

[0127] The difference between this embodiment and the first embodiment lies in the straight-line structure, in which the inlet and outlet of each single-use flow path are separated from each other. In this embodiment, the two ends of each single-use flow path are located at positions opposite to a second direction, which is orthogonal to the first direction in which the injection nozzle is arranged.

[0128] The advantages of this design include reduced concentration effects, because the inflow and outflow of each circulating stream are separated in opposite directions, and the ink concentrated at the nozzle does not flow back into the single-use flow path through the circulation.

[0129] Third Embodiment

[0130] Figures 13A to 13C This is a schematic diagram illustrating the vicinity of the nozzle of a liquid jet head that sprays a liquid, such as ink, in the third embodiment. Figure 13A This is a plan view taken along the direction in which the droplet is ejected from the nozzle. (Compared to...) Figure 12B and Figure 12C Similarly, Figure 13B and Figure 13C It is along Figure 13A Two examples of sectional views taken by the defined line AB.

[0131] The difference between this embodiment and the second embodiment is that three supply opening rows are provided, thereby doubling the number of injection port rows, and the injection port rows are located on the side closer to the central supply opening row. That is, injection port rows are formed on both sides of the array direction in which multiple supply openings are arranged. An injection port row is an array of injection ports 11 included in a row arranging multiple single-use injection units. That is, two rows are arranged parallel to each other on the right and left sides along the central supply opening row. Here, the central opening row shared by the first row and the second row is the second opening row where the second opening is arranged. Moreover, the opening row at the end portion provided for each of the first unit row and the second unit row is the first opening row where the first opening is arranged.

[0132] One advantage of this configuration is that the number of nozzle rows can be doubled from one to two by increasing the number of supply openings from two to three. As shown in the figure, two nozzle rows can also be arranged with an offset pitch. Furthermore, a configuration can be adopted in which no wiring area is required between the openings in the central supply opening row, and the size and resolution of the openings in the central supply opening row offer greater freedom. Therefore, the speed of refilling the nozzles is increased, making it easier to handle high productivity levels.

[0133] Although in this embodiment the three supply opening rows are arranged in the same position in the direction between the nozzle rows, the three rows can be offset from each other depending on the position of the nozzles and the extension of the wiring between the openings in each row. This also applies to the following embodiments.

[0134] Fourth embodiment

[0135] Figure 14A and 14B This is a schematic diagram illustrating the vicinity of the nozzle of a liquid jet head that sprays a liquid, such as ink, in the fourth embodiment. Figure 14A It is a plan view taken along the direction in which the droplet is ejected from the nozzle. Figure 14B It is along Figure 14A A cross-sectional view of the structure cut by the line AB that defines the middle part.

[0136] The difference between this embodiment and the third embodiment is that the direction of the circulating flow is reversed because the injection port row is located on the side of the supply opening row near both sides and the second energy generating element is located on the side of the supply opening row near the center.

[0137] One advantage of this design is that the ink concentrated near the nozzle branches into the supply openings on both sides and is then discharged, thus reducing the impact of concentrated ink when it flows back into the single-use flow path due to jetting or other reasons. Furthermore, since the nozzle rows are arranged separately from each other, interference caused by meniscus oscillations accompanying the jetting from each nozzle can be reduced.

[0138] Fifth Embodiment

[0139] Figure 15A and 15B This is a schematic diagram illustrating the vicinity of the nozzle of a liquid jet head that sprays a liquid, such as ink, in the fifth embodiment. Figure 15A It is a plan view taken along the direction in which the droplet is ejected from the nozzle. Figure 15B It is along Figure 15A A cross-sectional view of the structure cut by the line AB that defines the middle part.

[0140] The difference between this embodiment and the third embodiment is that the direction of the circulation flow is reversed because the second energy generating element is positioned close to the first energy generating element and the second energy generating element is closer to the central supply opening row (compared to the supply opening rows on both sides).

[0141] Some advantages of this configuration are that, since the degree of freedom in the size and resolution of the central supply opening row is as high as in the third embodiment, refilling can be performed more quickly to cope with high productivity, and because the ink concentrated near the nozzle branches into the supply opening rows on both sides and then discharges, the effect of concentrated ink is reduced when the ink flows back into the single-use flow path after jetting, etc.

[0142] Sixth Embodiment

[0143] Figures 16A to 16C This is a schematic diagram illustrating the vicinity of the nozzle of a liquid jet head that sprays a liquid, such as ink, in the sixth embodiment. Figure 16A It is a plan view taken along the direction in which the droplet is ejected from the nozzle. Figure 16B and 16C They are along Figure 16A A sectional view of the structure cut by the lines A-A' and B-B' that define the middle part.

[0144] The difference between this embodiment and the first embodiment is that the left and right rows of injection ports sandwiching the supply tank are arranged in an alternating manner, and a filter is also provided at the inlet of each single-use flow path (near the corresponding second energy generating element). The effects of this disclosure can also be achieved in this configuration.

[0145] According to this disclosure, a technique can be provided to optimize the amount of drive data in an ink circulating liquid jet head by using both a jet energy generating element and a flow energy generating element.

[0146] Although 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 following claims should be determined according to the broadest description in order to cover all such variations and equivalent structures and functions.

Claims

1. A liquid ejection head, comprising: a single-use ejection unit, the single-use ejection unit including: an ejection port for ejecting a liquid; a pressure chamber communicating with the ejection port; a first energy generating element provided in the pressure chamber and generating energy for ejecting a liquid from the ejection port; a single-use flow path communicating with the pressure chamber; and a second energy generating element provided in the single-use flow path; and a common flow path for supplying a liquid to the single-use flow paths of a plurality of the single-use ejection units, wherein 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 only after receiving a drive signal for issuing an instruction to drive the second energy generating element.

2. The liquid ejection head according to claim 1, wherein when the plurality of single-use ejection units are divided into a plurality of single-use ejection unit groups, for each of the single-use ejection unit groups, the driving of the first and second energy generating elements is controlled, and the drive signal for issuing an instruction to drive the second energy generating element is a signal of an instruction issued for each of the single-use ejection unit groups.

3. The liquid ejection head of claim 2, wherein: Each of the plurality of single-use ejection unit groups is a row of the plurality of single-use ejection units arranged in an array direction.

4. The liquid ejection head of claim 3, wherein: Each of the plurality of single-use ejection unit groups includes a plurality of rows.

5. The liquid ejection head of claim 2, wherein: Each of the plurality of single-use ejection unit groups is a block including the plurality of single-use ejection units.

6. The liquid ejection head of claim 2, wherein: The plurality of single-use ejection unit groups respectively correspond to the single-use ejection units ejecting liquids of different colors.

7. The liquid ejection head according to any one of claims 1 to 6, wherein: A plurality of ejection ports included in the plurality of single-use ejection units form an ejection port row.

8. The liquid ejection head of claim 7, wherein: In the single-use flow paths of the single-use ejection units, the first and second energy generating elements are arranged in a direction intersecting the ejection port row.

9. The liquid ejection head of claim 8, wherein: The single-use flow paths extend in a direction intersecting the ejection port row, such that both end portions of the single-use flow paths are positioned such that the ejection port row is interposed between the end portions.

10. The liquid ejection head according to claim 7, wherein the plurality of single-use flow paths of the plurality of single-use ejection units are connected with the common flow path via first openings and second openings, and each of the first and second openings is arranged along the ejection port row so as to form a first opening row and a second opening row.

11. The liquid ejection head according to claim 10, wherein: the plurality of single-use ejection unit groups in which the plurality of single-use ejection units are arranged are provided in parallel, the second opening row is provided between the plurality of single-use ejection unit groups and is shared by the plurality of single-use ejection unit groups, and the first opening row is provided for each of the plurality of single-use ejection unit groups.

12. The liquid ejection head of claim 11, wherein: The first energy generating element is arranged on a side of the single-use flow path close to the second opening.

13. The liquid ejection head of claim 11, wherein: The second energy generating element is arranged on a side of the single-use flow path close to the second opening.

14. The liquid ejection head of claim 7, wherein: In the single-use flow path, the first energy generating element and the second energy generating element are arranged along the ejection port row.

15. The liquid ejection head of claim 14, wherein: The single-use flow path has two end portions, both of which are located on one side of the ejection port row.

16. The liquid ejection head of any one of claims 1 to 6, wherein: The second energy generating element performs circulation driving for circulating liquid in the single-use flow path, and the first energy generating element performs ejection driving for ejecting liquid from the ejection port.

17. The liquid ejection head of claim 16, wherein: The circulation driving is driving performed with weaker energy than the ejection driving.

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