Liquid ejecting head and liquid ejecting method

Abstract

The invention discloses a liquid ejecting head and a liquid ejecting method. A liquid ejection method uses: a separate ejection unit comprising an ejection hole, a pressure chamber, a first thermal energy generating element disposed for the pressure chamber, a separate flow path in communication with the pressure chamber, and a second thermal energy generating element disposed for the separate flow path; and a liquid ejection head including a common flow path for supplying liquid to the plurality of individual flow paths of the plurality of individual ejection units. In driving control of the first thermal energy generating element and the second thermal energy generating element, when the first thermal energy generating element is driven, the second thermal energy generating element is not driven, and when the first thermal energy generating element is not driven, when a driving signal indicating driving with respect to the second thermal energy generating element is received, the second thermal energy generating element is driven. The second thermal energy generating element is driven.

Description

Technical Field

[0001] The present invention relates to a liquid ejecting head and a liquid ejecting method using the liquid ejecting head. Background Art

[0002] A circulating liquid ejection device is known that circulates ink to expel bubbles from the flow path within a liquid ejection head (hereinafter referred to as the "head") and suppress thickening of the ink near the ejection orifices. A system utilizing a pressure difference (hereinafter referred to as a "differential pressure system") is known as a method for circulating ink. In this system, a pressure adjustment mechanism is used to increase the pressure on the side supplying ink to the ejection orifices (IN side) to a higher pressure than the side collecting the ink (OUT side), thereby causing the ink to flow from the IN side to the OUT side. To circulate the ink, ink that has flowed to the OUT side must be returned to the IN side, requiring a pump as a mechanism for such return. Note that in some configurations, the pump is located outside the head of the printing device body, for example, to circulate the liquid between the liquid ejection head and the body, while in other configurations, the pump is located inside the liquid ejection head, circulating the liquid within the head. However, this differential pressure system circulation method requires a pressure adjustment mechanism and other mechanisms, such as a pump, and there is a risk of the printing device body and head being oversized.

[0003] Therefore, ink circulation methods other than differential pressure systems are being considered. Specifically, a known mechanism comprises providing a circulation flow path connected to the ejection orifice, and deploying an energy generating element (hereinafter also referred to as a "flow energy generating element") different from the energy generating element configured to eject ink (hereinafter also referred to as the "ejection energy generating element") in this circulation flow path. In this mechanism, the ink circulates in the circulation path by driving the flow energy generating element.

[0004] Japanese Patent Laid-Open No. 2020-104312 discloses a configuration in which a circulation flow path extending to intersect with an injection hole array including a plurality of injection holes arranged is provided, and the circulation flow path includes a flow energy generating element. Summary of the Invention

[0005] The present invention provides a liquid ejecting method, the liquid ejecting method using: a separate ejecting unit, the separate ejecting unit including: an ejection hole through which liquid is ejected; a pressure chamber, the pressure chamber communicating with the ejection hole; a first heat energy generating element, the first heat energy generating element being provided for the pressure chamber and configured to generate heat energy for ejecting liquid from the ejection hole; a separate flow path communicating with the pressure chamber, and a second heat energy generating element, the second heat energy generating element being provided for the separate flow path; and a liquid ejecting head including a common flow path for supplying liquid to a plurality of separate flow paths of a plurality of separate ejecting units, wherein the first heat energy generating element and the second heat energy generating element are controlled to be driven under the following conditions:

[0006] When the first heat generating element is driven, the second heat generating element is not driven, and

[0007] When the first heat energy generating element is not driven, upon receiving a driving signal instructing driving of the second heat energy generating element, the second heat energy generating element is driven.

[0008] The present invention provides a liquid injection head, which includes: a spray hole, through which liquid is ejected; a pressure chamber, which is connected to the spray hole; a first heat energy generating element, which is set for the pressure chamber and configured to generate heat energy for ejecting liquid from the spray hole; a separate flow path, which is connected to the pressure chamber; a second heat energy generating element, which is set for the separate flow path; and a drive circuit, which is configured to control the drive of the first heat energy generating element and the second heat energy generating element, wherein the drive circuit includes a first switch, which is capable of switching the first heat energy generating element and the second heat energy generating element exclusively with each other so as to only enable either one of the first heat energy generating element and the second heat energy generating element to enter a drivable state, and a second switch, which is capable of switching between a drivable state and a drive disabled state in the second heat energy generating element.

[0009] Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1A and Figure 1B Each is an overall view of an apparatus utilizing a liquid ejecting head.

[0011] Figures 2A to 2DIt is an overall view of the liquid ejection head and an overall view of the liquid ejection chip.

[0012] Figures 3A to 3D Each is a schematic diagram of the vicinity of an ejection hole of a liquid ejecting head.

[0013] Figures 4A to 4C Each is a schematic diagram of the vicinity of an ejection hole of a liquid ejecting head.

[0014] 5A to 5D Each is a schematic diagram of the vicinity of an ejection hole of a liquid ejecting head.

[0015] 6A to 6D Each is a schematic diagram of the vicinity of an ejection hole of a liquid ejecting head.

[0016] 7A to 7C Each is a schematic diagram of the vicinity of an ejection hole of the liquid ejection head in the first embodiment.

[0017] Figure 8 This is a circuit configuration diagram in a comparative configuration.

[0018] Figure 9 is a circuit configuration diagram in the first embodiment.

[0019] 10A to 10C Each is a schematic diagram of the vicinity of an ejection hole of a liquid ejection head in the second embodiment.

[0020] Figures 11A to 11C Each is a schematic diagram of the vicinity of an ejection hole of a liquid ejection head in the third embodiment.

[0021] Figure 12A and Figure 12B Each is a schematic diagram of the vicinity of an ejection hole of a liquid ejection head in a fourth embodiment.

[0022] Figure 13A and Figure 13B Each is a schematic diagram of the vicinity of an ejection hole of a liquid ejection head in the fifth embodiment.

[0023] 14A to 14C Each is a schematic diagram of the vicinity of an ejection hole of a liquid ejection head in the sixth embodiment.

[0024] Figures 15A to 15C Each illustrates the driving timing of the energy generating element in the first embodiment. DETAILED DESCRIPTION

[0025] However, Japanese Patent Publication No. 2020-104312 does not yet describe what driving data is used to drive the ejection energy generating element and the flow energy generating element, each of which is an electrothermal conversion element. Generally, it is conceivable to provide driving data for each of the energy generating elements, but the amount of data increases according to the number of energy generating elements. Therefore, the present invention provides a liquid ejection head and a liquid ejection device, which can be driven with an optimal amount of data in an ink circulation system as in Japanese Patent Publication No. 2020-104312 using the ejection energy generating element and the flow energy generating element in combination.

[0026] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Note that the following embodiments are not intended to limit the contents of the present disclosure, and not all combinations of features described in the embodiments of the present invention are necessary for the solutions of the present disclosure. Note that the same reference numerals are used to represent the same constituent elements. In the following description, the basic configuration of the present disclosure is first described, and then the features of the present disclosure are described.

[0027] Liquid injection equipment

[0028] First, a schematic configuration of the liquid ejecting apparatus 50 in this embodiment will be described. Figure 1A and Figure 1B Each is an enlarged view of the liquid ejecting head 1 of the liquid ejecting apparatus 50 and its surrounding area, and each is a perspective view schematically illustrating the liquid ejecting apparatus using the liquid ejecting head. Figure 1A and Figure 1B The liquid ejection device 50 shown in the figure is a (serial type) liquid ejection device that prints an image by ejecting liquid onto a print medium P using a liquid ejection head that scans in a direction intersecting the conveying direction of the print medium P. The present invention is applicable not only to serial type liquid ejection devices, but also to page width type liquid ejection devices that print an image on a print medium conveyed in the conveying direction by ejecting liquid using a line head (page width type head) that is long in the page width direction of the print medium. It is noted that the liquid ejection head in the embodiment of the present invention is capable of ejecting four types of ink, namely black (K), cyan (C), magenta (M) and yellow (Y), and is capable of printing a full-color image with these inks. The ink that can be ejected from the liquid ejection head is not limited to the above four types of ink. The present disclosure is also applicable to a liquid ejection head that is configured to eject another type of ink. That is, the ink type and amount of ink ejected from the liquid ejection head are not limited.

[0029] In the serial-type liquid ejecting apparatus 50, the liquid ejecting head 1 is mounted on a carriage 60. The carriage 60 reciprocates in the main scanning direction (X direction) along a guide shaft 51. The print medium is transported in the sub-scanning direction (Y direction) intersecting (orthogonal in the embodiment of the present invention) the main scanning direction by transport rollers (transport units) 55, 56, 57, and 58. Note that in each of the following figures, the Z direction indicates the vertical direction and intersects (orthogonal in the embodiment of the present invention) the XY plane defined by the X and Y directions.

[0030] Figure 1A The figure shows a configuration in which the main ink tank 2 serving as a liquid storage is provided outside the liquid ejecting head. The liquid (ink) stored in the ink tank 2 is supplied to the sub-ink tank 54 on the liquid ejecting head 1 side through, for example, an ink supply tube (liquid communication path) 59 by the driving force of an external pump. On the other hand, Figure 1B The figure shows a configuration in which the ink tank 54 is provided just above the liquid ejecting head 1 (no main ink tank 2 serving as a liquid reservoir is provided outside the liquid ejecting head). At this time, in some cases, the liquid ejecting head 1 is provided integrally with the ink tank 54 and is detachable / attachable relative to the carriage 60, while in other cases, the liquid ejecting head 1 is provided integrally with the carriage 60 and only the ink tank 54 is detachable / attachable. Hereinafter, when using Figure 1A The configuration in is described as a representative example.

[0031] The liquid ejection head 1 includes individual ejection units (refer to Figures 2A to 2D ).

[0032] Although the specific configuration will be described later, the individual ejection units include an ejection hole through which liquid is ejected, a pressure chamber communicating with the ejection hole, a first energy generating element (ejection energy generating element) provided for the pressure chamber and configured to generate energy for ejecting the liquid through the ejection hole, an individual flow path communicating with the pressure chamber, and a second energy generating element (flow energy generating element) provided for the individual flow path. The liquid ejection head 1 includes a plurality of individual ejection units and includes a supply flow path for supplying liquid to the individual flow paths in each of the individual ejection units.

[0033] When using a liquid ejection head, the ejection of the liquid may become unstable due to, for example, evaporation of volatile components such as water from the ejection orifice and condensation of solid contents near the ejection orifice accompanying the evaporation, and various inventions have been made to prevent such evaporation and condensation. For example, in a liquid ejection device, a cover member (not shown) may be provided at a position deviating from the transport path of the print medium in the X direction, which cover member is capable of covering the ejection orifice surface where the ejection orifice of the liquid ejection head is formed. The cover member is used to prevent the ejection orifice from drying out and protect the ejection orifice by, for example, covering the ejection orifice surface of the liquid ejection head when a printing operation is not being performed. An ink suction mechanism (not shown) may also be provided, and in this case, the cover member is used for an operation to suck ink from the ejection orifice or other operations. By performing such an ink suction operation, the ink near the ejection orifice is refreshed, and the quality of the image that can be obtained can be maintained. There are also known methods for discarding concentrated ink by performing a so-called preliminary ejection when printing is not in progress, and methods for preliminarily ejecting a certain amount of ink (preliminary ejection on the paper surface / preliminary ejection within the page) at a certain point on the print medium during printing, so that the ejected ink is not noticeable in terms of image quality. These methods significantly contribute to improving image quality, but because a portion of the ink is discarded to refresh the ejection orifices, it is necessary to minimize the amount of waste ink.

[0034] To address these challenges, by placing a second energy generating element (flow energy generating element) in a separate flow path and circulating the ink within the flow path, it is possible to suppress drying out of the ejection port and ink condensation near the ejection orifice, while also suppressing increases in the amount of waste ink. More specifically, the number of preliminary ejections and suction recovery can be minimized. Furthermore, minimizing the number of preliminary ejections, for example, can improve production throughput and yield.

[0035] The second energy generating element (flow energy generating element) does not need to be provided in each individual ejection unit of the liquid ejection head. Compared to the case where no second energy generating element is provided, the above-mentioned effect can be achieved even if the second energy generating element (flow energy generating element) is provided for some of the individual ejection units.

[0036] Figure 1A The liquid ejection head illustrated in FIG can have a configuration in which the second energy generating element is provided at all dots corresponding to four types of ink, or can have a configuration in which the second energy generating element is provided at only dots corresponding to one type of ink. In other words, the liquid ejection head can be configured to circulate only at least one type of ink, rather than all four types of ink.

[0037] Basic configuration of liquid ejection head

[0038] Figure 2A FIG is an exploded perspective view of a liquid ejecting head according to an embodiment of the present invention. Figures 2A to 2D As shown in the figure, the liquid ejection head includes a sub-ink tank 54 that allows ink to be temporarily stored in the head and a liquid ejection chip 3 for ejecting ink supplied from the sub-ink tank 54 onto the printing medium P. The liquid ejection head in this embodiment is fixed to and supported by the carriage by using a positioning unit and electrical contacts (not shown) provided in the carriage of the liquid ejection device. Figure 1A Ink is ejected while the carriage moves in the main scanning direction (X direction) shown in FIG. 1 , and printing is performed on the print medium P.

[0039] The ink supply tube 59 is provided for an external pump connected to the ink tank 2 serving as a supply source of ink (refer to Figure 1A ). A liquid connector (not shown) is provided at the distal end of the ink supply tube. When the liquid ejecting head 1 is mounted on the liquid ejecting apparatus 50, the liquid connector provided at the distal end of the ink supply tube 59 is liquid-tightly connected to a liquid connector insertion groove provided in the head housing of the liquid ejecting head 1 and serving as an introduction port for liquid.

[0040] Thus, an ink supply path is formed from the ink tank 2 to the liquid ejection head 1 through the external pump. In the present embodiment, since four types of ink are used, four sets of ink tanks 2, external pumps, ink supply tubes 59, and sub-ink tanks 54 are provided corresponding to the respective inks, and four ink supply paths corresponding to the respective inks are independently formed. As described above, the liquid ejection device according to the present embodiment is provided with an ink supply system through which ink is supplied from the ink tank 2 provided outside the liquid ejection head 1. It is noted that the liquid ejection device according to the present embodiment is not provided with any ink collection system for collecting the ink inside the liquid ejection head into the ink tank. Therefore, the liquid ejection head has a liquid connector insertion groove for connecting the ink supply tube of the ink tank, but does not have a connector insertion groove for connecting a tube for collecting ink in the liquid ejection head into the ink tank. It is noted that a liquid connector insertion groove is provided for each ink.

[0041] Figures 2B to 2D Each is an overall view of a liquid ejection chip constituting a liquid ejection head. Figure 2B The diagram shows a configuration where one chip is set for each of four colors. Figure 2C The diagram shows a configuration where one chip is set for every two colors, and Figure 2D The figure shows a configuration in which one chip is provided for each color. Each of the liquid ejection chips includes an ejection hole and a pad for electrical mounting. Figure 2A In the Figure 2B chip configuration.

[0042] Figure 2B The diagram illustrates a first configuration example in which one chip is configured for each of four colors. For example, the four colors are black, cyan, magenta, and yellow, and arrays are formed for each color and arranged in the Y direction. The ejection holes in each adjacent array are offset in the X direction and evenly spaced along the Y direction. Here, the ejection holes in adjacent arrays can be arranged in a single array along the Y direction without offsetting in the X direction. Alternatively, two arrays can be provided for black alone, and a total of five arrays can be provided for the four colors.

[0043] Figure 2C A second configuration example using two chips is illustrated, each chip being configured with two colors.

[0044] When such two chips are mounted in a liquid ejection head, the two chips may be mounted in one liquid ejection head, or two heads each including one chip may be prepared.

[0045] Figure 2D The diagram shows a third configuration example using four chips, one for each color. Figure 2C Likewise, such four chips may be mounted in one liquid ejecting head, or four heads each including one chip may be prepared.

[0046] In such Figure 2C and Figure 2D In the case of multiple chips divided in, not all chips need to have the same chip length. In addition, various other combinations of the number of colors of the chips are possible, and the same applies to the case where the total number of colors is more than four.

[0047] Constituent elements of the cycle unit

[0048] Line type

[0049] Figures 3A to 3D Each is a schematic diagram for illustrating the vicinity of an ejection hole of a linear type liquid ejection head.

[0050] The "straight line type" here refers to a type in which a separate flow path in which the first energy generating element (jet energy generating element) and the second energy generating element (flow energy generating element) are disposed has a straight line shape that intersects with the jet hole array (at Figures 3A to 3D In the case of a jetting unit, the first energy generating element and the second energy generating element extend in a direction (orthogonal) such that both ends of the individual flow path are positioned on either side of the jet hole array. In other words, in the individual flow paths of the individual jetting units, the first energy generating element and the second energy generating element are arranged in a direction intersecting the jet hole array.

[0051] Figure 3AThis is a plan view when viewed from the side where the droplets are ejected from the ejection hole. Figure 3B It is along Figure 3A A cross-sectional view taken along line IIIB-IIIB in FIG. Figure 3C It is along Figure 3A Another cross-sectional view taken along line IIIC-IIIC in FIG. Figure 3D The diagram illustrates the inflow of ink when the first energy generating element is driven.

[0052] exist Figures 3A to 3C In the embodiment, between the substrate 18 and the orifice plate 19, there are formed a pressure chamber 12 partitioned by a partition plate 21 and corresponding to each ejection hole 11, and a separate flow path 23 for causing the ink to flow when passing through the corresponding pressure chamber 12. A meniscus of ink is formed in each of the ejection holes 11 as an ejection hole interface between the ink and the atmosphere.

[0053] The substrate 18 is provided with a first energy generating element 14, which is an electrothermal conversion element configured to generate energy for ejecting ink within the pressure chamber. The first energy generating element 14, along with the ejection orifice 11 and the pressure chamber 12, is positioned closer to the second supply opening 32 than the first supply opening 22. The first energy generating element 14 is driven to generate heat and bubbles in the ink within the pressure chamber 12, thereby utilizing this bubble generation energy to eject ink from the ejection orifice 11.

[0054] The substrate 18 is also provided with a second energy generating element 24 which is an electrothermal conversion element configured to generate energy for generating a circulating flow 27 of ink indicated by arrows inside the individual flow paths.

[0055] In addition, the substrate 18 has an opening through which the liquid is supplied from the common flow path to the individual flow paths. Figure 3A In the embodiment, multiple openings (independent supply openings) can be provided, or as will be described later Figure 7A In the embodiment of the present invention, a supply groove formed as a large opening may be provided. The second energy generating element 24 is located closer to the first supply opening 22 than the second supply opening 32 .

[0056] The separate flow path 23 extends in a second direction that intersects (in the embodiment of the present invention, is orthogonal to) the direction (first direction) in which the injection holes are arranged in an array. The separate flow path 23 includes the pressure chamber 12, a pressure chamber 12 connected to an end portion on one side of the pressure chamber 12 and positioned at Figure 3B The connecting flow path 13 on the inlet side (upstream) of the pressure chamber 12 and the end portion on the other side thereof are connected and positioned at Figure 3BThe connecting flow path 13 is a flow path on the outlet side (downstream) of the nozzle. The separate flow path 23 communicates with the first supply opening 22 and the second supply opening 32, each of which passes through the substrate 18, at one end on the upstream side and the other end on the downstream side. Therefore, the connecting flow path 13 is positioned closer to the second energy generating element than the injection hole array. The two ends of the separate flow path 23 are positioned on opposite sides of the injection hole array.

[0057] The ink flow moving in the separate flow paths is roughly divided into two: (1) a first ink flow for refilling after ejection performed by driving the first energy generating element 14 and (2) a second ink flow for forming a circulating flow generated by driving the second energy generating element 24.

[0058] When the first energy generating element 14 is driven to eject the liquid from the ejection hole 11, in order to Figure 3D Ink associated with the ejection is supplied from the first supply opening 22 and the second supply opening 32 as shown in FIG. 2 , so that the ink flows from the two supply openings into the pressure chamber.

[0059] When the second energy generating element 24 is driven to form a circulating flow, ink flows in through the first supply opening 22, which is the connecting flow path side, and flows out through the second supply opening 32, which is not the connecting flow path side, with respect to the separate flow path 23. In this embodiment, the ink flowing out of the second supply opening 32 circulates by returning to the first supply opening 22, thereby forming a circulating flow 27 indicated by the arrow inside the separate flow path 23. Note that in Figure 3B FIG shows a configuration in which the first supply opening 22 and the second supply opening 32 are shared within the chip. Figure 3C A configuration in which the first supply opening 22 and the second supply opening 32 are connected to separate flow paths and are shared outside the print head is illustrated in FIG, but any configuration may be used.

[0060] A filter 31 for removing foreign matter from the ink may be provided in the circulation flow path of the ink inside and outside the print head. Figures 3A to 3D In the embodiment, the filter is disposed on each of the inflow side and the outflow side, which are outside the separate flow path. Alternatively, the filter may be disposed between the first energy generating element and the second energy generating element in the separate flow path. In this case, the filter is not necessarily disposed on the upstream side (on the side of the second energy generating element) outside the separate flow path.

[0061] U-shaped type

[0062] The first embodiment described later in this article will be used 7A to 7CThe following describes the U-shaped liquid ejection head near the ejection orifice. The "U-shaped" design refers to a configuration that includes a U-shaped flow path in which a first energy generating element (ejection energy generating element) and a second energy generating element (flow energy generating element) are deployed. In other words, the first and second energy generating elements are deployed along the ejection orifice array in separate flow paths.

[0063] In the individual flow path, both end portions thereof are positioned on one side relative to the injection hole array. Figure 7A This is a plan view when viewed from the side where the droplets are ejected from the ejection hole. Figure 7B It is along Figure 7A A cross-sectional view taken along line VIIB-VIIB in FIG. Figure 7C It's a picture Figure 7A Schematic enlarged view of the component names in the individual flow path sections.

[0064] exist 7A to 7C In the embodiment, both the first energy generating element 14 and the second energy generating element 24 are positioned near the supply groove 42. The first energy generating element and the second energy generating element are alternately arranged in the direction (first direction) in which the injection holes are arranged in an array, and the separate flow path 23 is formed in a curved shape (U-shape) to connect the energy generating elements. The separate flow path 23 includes the pressure chamber 12, a portion communicating with an end portion of one side of the pressure chamber 12 and positioned at Figure 7B The connecting flow path 13 on the inlet side (upstream) of the pressure chamber 12 and the end portion on the other side thereof are connected and positioned at Figure 7B The individual flow path 23 is connected to the outlet side (downstream) of the substrate 18. The individual flow path 23 communicates with the supply groove 42 passing through the substrate 18 on both its upstream and downstream sides. Both ends of the individual flow path 23 are positioned adjacent to each other on one side of the supply groove 42.

[0065] As with the straight line type, the flow of ink moving in a separate flow path is divided into two: (1) a first ink flow and (2) a second ink flow.

[0066] When the first energy generating element 14 is driven to eject liquid from the ejection hole 11 , in order to supply ink associated with the ejection from the supply groove 42 , ink is caused to flow into the pressure chamber from the connection flow path side and the opposite side.

[0067] When the second energy generating element 24 is driven to form a circulating flow, ink flows from the inlet side (upstream) as the connecting flow path side and flows out to the outlet side (downstream) relative to the individual flow path 23. In this embodiment, due to the inflow and outflow to the common supply groove 42 on both sides, a circulating flow 27 indicated by the arrow is formed inside the individual flow path 23. Note that the supply groove 42 is shown in this embodiment, but it can be replaced with a similar one. Figures 3A to 3D When the supply openings are replaced, as shown in FIG. Figure 3B Likewise, the supply openings are shared within the chip.

[0068] Pump Principle

[0069] Figures 4A to 4C Each is a diagram for illustrating the principle of generation of a circulation flow of ink when the second energy generating element (circulation heater) 24 as an electrothermal conversion element is used. Figure 3B Same, Figures 4A to 4C 2 are cross-sectional views illustrating the generation and growth process, the contraction process, and the post-bubble disappearance process when the ink is heated by the circulation heater 24 and the bubble B is generated. Figure 4A In FIG. 3 , the circulation heater 24 is positioned closer to the first supply opening 22 than the second supply opening 32 . Therefore, the flow resistance R1 between the circulation heater 24 and the first supply opening 22 is smaller than the flow resistance R2 between the circulation heater 24 and the second supply opening 32 . Figure 4A The flow resistances R1 and R2 are each expressed as an equivalent circuit combination of resistors. Due to the difference between the flow resistances R1 and R2, as Figure 4A In the flow path 23, the bubble B generated by film boiling of the ink grows toward the first supply opening 22 side having the smaller flow resistance R1. Therefore, inside the single flow path 23, the flow Fa of the ink toward the first supply opening 22 is greater than the flow Fb of the ink toward the second supply opening 32.

[0070] Figure 4B The figure shows the ink flow during the shrinkage process of the bubble B. During the shrinkage process of the bubble B, ink flows in to compensate for the shrinkage volume. Figure 4B Likewise, the flow Fc of the ink flowing in from the first supply opening 22 on the side of the small flow resistance R1 is larger than the flow Fd of the ink flowing in from the second supply opening 32 on the side of the large flow resistance R2.

[0071] In addition, the position where the bubbles B disappear is shifted from the point above the circulation heater 24 to be closer to the second supply opening 32 .

[0072] Figure 4CThe figure shows the post-bubble disappearance process of bubble B. Figure 4B The relationship Fc>Fd generated in the above equation generates a circulating flow F of ink from the first supply opening 22 toward the second supply opening 32 .

[0073] The size of such a circulation flow F is affected by the ratio of the flow resistance R1 to R2 and the size of the bubble B. For example, assuming that a circulation heater 24 as an electrothermal conversion element is used as the second energy generating element 24, the second energy generating element 24 can be closer to either end of the separate flow path 23 than the first energy generating element. More specifically, the flow resistance ratio R1 / R2 can be set in the range of 0.05 to 0.40. By setting the flow resistance ratio R1 / R2 in the above range, the circulation flow F can be set to the maximum value. For the circulation flow F, it is important to increase the flow resistance toward Figure 4A and Figure 4B , and increases the flow Fc of the ink flowing in from the first supply opening 22. Therefore, it is effective to reduce the flow resistance R1. It is also important to reduce the flow Fd of the ink flowing in from the second supply opening 32 by minimizing the flow Fb of the ink toward the outflow path. Therefore, it is effective to increase the flow resistance R2. According to the above, it is important to reduce the flow resistance R1 and increase the flow resistance R2, that is, to reduce the flow resistance ratio R1 / R2. In addition, the large bubbles B (that is, the large bubble volume) cause an increase in the excluded volume of the fluid generated in the separate flow path 23, thereby increasing the size of the circulating flow F. Examples of ways to increase the bubble volume include:

[0074] - Increased size of circulation heater 24

[0075] - Reducing flow resistance by increasing the width and / or height of the inner side of the flow path 13

[0076] -Ink viscosity is reduced

[0077] -Head temperature increases

[0078] -Double pulse of driving pulse

[0079] As part of the ink circulation flow F enters the ejection hole 11, the concentrated ink inside the ejection hole 11 is sent to the second supply opening 32 side, thereby allowing fresh ink to flow from the first supply opening 22 side into the ejection hole 11 through the connecting flow path 13. As described above, by making it difficult for the concentrated ink to remain inside the ejection hole 11, the influence of the concentrated ink is suppressed, and the initial ink ejection state can be maintained.

[0080] The circulation flow F is a transitional flow associated with the growth process and the contraction process when the bubbles B are generated.

[0081] Therefore, after the bubble B disappears, the inertial flow decays over time and stops after a predetermined period of time. Therefore, the heating element of the circulation heater 24 needs to be repeatedly driven to stably generate the circulating flow F over a certain period of time. The driving cycle of the circulation heater 24 is not particularly limited, as long as the concentrated ink inside the ejection hole 11 can be discharged. However, due to the transient flow associated with the growth and contraction process during the generation of the bubble B, the effect is weakened when driven at a high driving frequency such as 100 kHz, considering the 10 μs period from bubble generation to disappearance. Therefore, for example, the circulation heater 24 can be driven at a cycle of approximately 100 Hz to several tens of kHz. Since the circulating flow F is maintained as the driving frequency increases, the effect of discharging the concentrated ink is enhanced. However, on the other hand, the increase in ink temperature caused by the heat generated by the driving of the circulation heater 24 needs to be considered. Therefore, it is necessary to drive the circulation heater 24 at an appropriate number of times.

[0082] Recirculation concentration

[0083] 5A to 5D and 6A to 6D Each is a diagram for illustrating how condensation is eliminated using the circulating flow of ink generated by the second energy generating element. 5A to 5D A straight-line type configuration is illustrated in which the inlet and outlet for the circulation flow in the individual flow paths are separated from each other, and 6A to 6D The diagram shows a U-shaped configuration in which the inlet and outlet for the circulation flow in the separate flow paths are adjacent. Note that the points where the ink is concentrated are indicated by a dark color, and the degree of concentration is represented by the lightness or darkness of the color.

[0084] First, in 5A to 5D middle, Figure 5A The figure shows a temporary stop state. During the temporary stop, volatile components evaporate from the ejection hole portion, and the ink is concentrated near the ejection hole. Figure 5B The diagram shows the state immediately after the second energy generating element generates a circulating flow. The circulating flow eliminates the concentration near the ejection hole. The ink concentrated near the ejection hole is discharged from the outlet, and the concentration is eliminated throughout the single flow path. Figure 5C The figure shows another temporary stop state after this. Figure 5A Similarly, the ink is concentrated again near the ejection hole. From there, Figure 5D The diagram shows the state immediately after another circulating flow is generated by the second energy generating element. Figure 5BSimilarly, the concentration near the injection hole is eliminated again, and the concentration is also eliminated in the entire independent flow path. As described above, in the straight line type where the inlet and outlet of the independent flow path are separated, the concentrated state is reset every time the temporary stop and such a cycle operation are repeated.

[0085] On the other hand, 6A to 6D middle, Figure 6A The figure shows the temporary stop state. During the temporary stop, Figure 5A Similarly, the ink is concentrated near the ejection hole. Figure 6B The diagram shows the state immediately after the second energy generating element generates a circulating flow. Here, by arranging the inlet and outlet of the separate flow path adjacent to each other, ink concentrated near the ejection orifice is discharged from the outlet but flows back in from the inlet. Consequently, the entire separate flow path is replaced with slightly concentrated ink, rather than fresh ink (hereinafter referred to as recirculating concentration). Figure 6C Another temporary stop state after this is shown. In this case, further Figure 6B From the state, such as Figure 6A As shown in the figure, the ink is concentrated again near the ejection hole. From there, Figure 6D , the state immediately after another circulating flow is generated by the second energy generating element is illustrated. Figure 6B As shown, under the recirculation concentration effect, the replacement of the concentrated ink with the ink in the entire individual flow path is carried out. Figure 6B As described above, in a U-shaped configuration where the inlet and outlet of a separate flow path are adjacent, the concentrated state is not reset during repeated temporary stops and circulation operations, and concentration gradually progresses throughout the separate flow path, causing the concentrated state to deteriorate. Furthermore, even without repeated circulation operations, if concentration near the injection orifice increases due to, for example, a long stop time, it becomes difficult to improve the concentrated state even in the first circulation operation. This is because the concentrated state is minimally improved due to the recirculation of the concentrated state.

[0086] Therefore, due to the difference in the influence of discharged concentrated ink, the state of concentration elimination through temporary stop and circulation differs between the straight-line type (where the inlet and outlet of a single flow path are separated) and the U-shaped type (where the inlet and outlet of a single flow path are adjacent). In the straight-line type, the concentrated state encompassing the entire single flow path is easily eliminated, making it less likely that the concentrated ink will cause a decrease in ejection stability. On the other hand, in the U-shaped type, the concentrated state encompassing the entire single flow path is difficult to eliminate due to the recirculation of the concentrated ink, resulting in the possibility of unstable ejection depending on the concentration of the entire single flow path.

[0087] ink

[0088] As described so far, while the degree of condensation reduction varies depending on the flow path configuration, using a second energy generating element to generate a circulating flow of ink within a separate flow path can suppress the effects of concentrated ink thickening due to evaporation at the ejection orifice. This means that since the ink's ejection state can be maintained effectively, the effects of, for example, variations in ejection velocity can be further reduced, making stable ejection easier to achieve.

[0089] On the other hand, depending on the application of the liquid ejection head and the liquid ejection device on which the head is mounted, it is assumed that inks having different types of color materials and different solid content contents are to be used. That is, the ability to maintain a high level of ejection stability regardless of the ink used can be the performance of the liquid ejection head. For example, for problems such as curling (warping) and wrinkling (wavy wrinkles) in plain paper that may be caused by water in the ink, it is considered to use inks with reduced water content. Since inks with a small amount of water have a high concentration of organic solvents and solid contents such as pigments and resins in addition to water, the viscosity is likely to increase sharply as the water evaporates, thereby potentially reducing the ejection stability of the ink. For such inks, since the viscosity increase of the ink can be suppressed, a method of generating a circulating flow inside the pressure chamber as in the present invention is very effective. Inks with a large amount of solid content generally indicate a solid content of 10% by weight. That is, the present invention can be applied to inks in which the content of the solid content in the ink is 10% by weight (mass %) or greater.

[0090] Regarding the temperature during head operation, it is possible to use ink at a predetermined temperature, which is achieved by heating the ink using heaters deployed and controlled throughout the chip. Since ink viscosity varies with temperature, the viscosity of the ink at the head operating temperature affects ejection stability.

[0091] When a circulating flow is formed by the second energy generating element, the circulating flow velocity can be a value ranging from tens of mm / s to 1000 mm / s in terms of instantaneous flow velocity. The average flow velocity observed over a time range of several hundred microseconds depends on the drive frequency of the circulation heater. This is because, in the case of a circulation heater, the circulating flow is a transient flow that decays over time and ceases after a predetermined period of time. When driven at a frequency (injection frequency) of approximately 10 kHz to 20 kHz, similar to the drive frequency of the first energy generating element, an average flow velocity of several mm / s to 100 mm / s can be achieved.

[0092] When using an ink with a high pigment concentration - that is, for example, an ink with a viscosity of 3 cP or more and 6 cP or less at the head operating temperature, the ink may thicken in the ejection hole portion depending on the non-ejection time (stop time). As a result, the ejection speed may vary, thereby potentially reducing the ejection stability. Therefore, it is necessary to perform ink circulation when the stop time is still short, and it is necessary to eliminate the concentration by performing a stable ink circulation or a transition ink circulation at a high frequency. When a circulation heater is used as the second energy generating element, a transition ink circulation is formed, and thus, performing a circulation operation at a high frequency can help eliminate the concentration in the ejection hole portion.

[0093] On the other hand, when using ink with a low pigment concentration—that is, for example, an ink with a viscosity of 1 cP or greater and 2 cP or less at the head operating temperature—the jetting velocity may vary depending on the non-jetting time (stop time), but the effect is relatively small compared to high-concentration ink. On the other hand, when the stop time is long, for example, depending on the non-printing drive time (stop time), the ink thickens at the jetting orifice. Therefore, when the device is restarted after being stopped for a predetermined period of time without printing, it is necessary to perform recovery processes involving waste ink, such as suction operations, wiping operations, and preliminary ejection combined with suction and wiping operations. When a circulation heater is used as the second energy generating element, forming a circulating flow as a recovery process can help eliminate condensation at the jetting orifice without generating waste ink. Depending on the stop time, it is also possible to avoid generating waste ink by using only a circulation operation for recovery. Another recovery process for minimizing waste ink can be achieved by partially incorporating a suction operation, for example, for removing bubbles inside the head, when performing a circulation operation for recovery, which is different from the suction operation used for eliminating condensation.

[0094] In both high-concentration and low-concentration inks, the ink can be returned to its original state as quickly as possible to minimize the effects of concentrated ink. Therefore, even when a circulation heater is used as the second energy generating element, the effects of recirculation concentration are minimized, resulting in a better circulation effect. This means that a straight-line configuration is more efficient than a U-shaped one.

[0095] First embodiment

[0096] 7A to 7C Each is a schematic diagram illustrating in detail the vicinity of an ejection orifice of a liquid ejection head that ejects liquid such as ink in the first embodiment. Figure 7A This is a plan view when viewed from the side where the droplets are ejected from the ejection hole. Figure 7B It is along Figure 7A A cross-sectional view taken along line VIIB-VIIB in FIG. Figure 7CIt's a picture Figure 7A Schematic enlarged view of the component names in the individual flow path sections. Figure 8 is a block diagram illustrating a selective driving circuit configuration on a substrate in a comparative configuration, and Figure 9 is a block diagram illustrating the configuration of a selective driving circuit on a substrate in this embodiment.

[0097] exist Figure 7A and Figure 7B In the embodiment of the present invention, the injection hole 11 through which the liquid is injected is formed in the orifice plate 19. The first energy generating element 14 is formed in the substrate 18 directly below the injection hole 11. The second energy generating element 24 is formed in the substrate 18 in a similar manner together with the first energy generating element 14 to form a circulation flow 27 in the separate flow path 23. Liquid is supplied from the supply groove 42 to the separate flow path 23 including the injection hole 11. At this time, both ends of the separate flow path are adjacent in the first direction, which is the direction in which the injection holes are arranged.

[0098] Here, in Figure 7A In a system called a U-shaped type because of the shape of the flow path illustrated in FIG, both ends of the individual flow paths are adjacent in a first direction in which the injection holes are arranged. Figure 8 and Figure 9 The name of each component is also used in Figure 7C As shown, a first energy generating element 14 and a second energy generating element 24 are provided in each of the individual flow paths 23. To distinguish the elements from each other, each first energy generating element is referred to as Ai (i=1, 2, 3, ..., n), and each second energy generating element is referred to as Bi (i=1, 2, 3, ..., n). In this regard, for example, A1 and B1 are referred to as those disposed in the same individual flow path.

[0099] Comparing drive methods in configurations

[0100] In the comparison configuration, such as Figure 8The selective drive circuit 200 shown in the figure is formed on the substrate 18. The voltage source (+V) and the controller 110 are provided outside the substrate and are connected to the selective drive circuit 200 on the substrate. An ON-OFF drive circuit (ON-OFF switch) 210 is included, which drives the first energy generating element (A1 to A8) or the second energy generating element (B1 to B8) by turning them on or off in response to a control signal at each address (in this configuration, N1 to N16) received from the control data supply circuit 100. That is, each of the first energy generating element and the second energy generating element is independently controlled by a switch that can be switched between a drivable state and a drive disabled state. In the drivable state, the energy generating element can be driven, and in the drive disabled state, the energy generating element cannot be driven. Here, the control data supply circuit controls the drive pulse used to drive the first energy generating element or the second energy generating element and the time interval for applying the drive pulse to each element.

[0101] In a comparative configuration, the first and second energy generating elements are linked using different addresses, and separate drive circuits are also required. Therefore, separate drive data must be provided to the first and second energy generating elements. Consequently, the amount of data required increases depending on the total number of elements in the combination of the first and second energy generating elements.

[0102] Driving method in the embodiment: conversion drive

[0103] In this embodiment, if Figure 9 The selective drive circuit 200 shown in FIG is formed on the substrate 18. The voltage source and the controller 110 are provided outside the substrate and are connected to the selective drive circuit 200 on the substrate. An ON-ON drive circuit (a first switch that performs ON-ON switching) 230 is included. This ON-ON drive circuit drives any one of the first energy generating elements (A1 to A16) and the second energy generating elements (B1 to B16) by turning on the control signal at each address (in this embodiment, N1 to N16) received from the control data supply circuit 100. That is, a switch is provided that can switch the first energy generating element and the second energy generating element to only one of the energy generating elements into a drivable state. With this switch, when the first energy generating element is in a drivable state, the second energy generating element is always in a drive-disabled state, and on the other hand, when the second energy generating element is in a drivable state, the first energy generating element is always in a drive-disabled state. Here, the control data supply circuit 100 controls a driving pulse for driving the first energy generating element or the second energy generating element and a time (interval) of applying the driving pulse to each element.

[0104] Even when the second energy generating element side is selected in the ON-ON drive circuit 230, the drive is controlled by the ON-OFF drive circuit for the second energy generating element (the second switch that performs ON-OFF switching) 240 in response to another drive propriety signal 300 of the second energy generating element. That is, the second energy generating element is further controlled by a switch that can switch between a drivable state and a drive disabled state. Therefore, when the first energy generating element is in the drive disabled state, the second energy generating element is in a drivable state, but is actually only driven when a drive signal (drive propriety signal) indicating drive relative to the second energy generating element is received. In the absence of a drive signal, the second energy generating element is not driven even when the second energy generating element side is selected in the ON-ON drive circuit 230. That is, at this time, neither the first energy generating element nor the second energy generating element is driven.

[0105] In summary, in this embodiment, the driving circuit configured to control the driving of the first energy generating element and the second energy generating element includes: a first switch, which can drive the first energy generating element and the second energy generating element exclusively to make only any one of the energy generating elements enter a drivable state; and a second switch, which can switch between a drivable state and a drive disabled state in the second energy generating element, and the first energy generating element and the second energy generating element are controlled to be driven by the driving circuit under the following conditions.

[0106] 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, upon receiving a drive signal instructing driving of the second energy generating element, the second energy generating element is driven.

[0107] In addition, the ON-OFF drive circuit (second switch) can be positioned closer to the second energy generating element than the ON-ON drive circuit (first switch), that is, electrically downstream relative to the second energy generating element. In addition, the plurality of second energy generating elements can be controlled to be driven using a drive signal common to them.

[0108] Figures 15A to 15C Each diagram shows the Figure 9 The driving timing of each energy generating element of the circuit of each energy generating element shown in FIG. For the sake of simplicity, the case of two groups of first energy generating elements and second energy generating elements is shown, but this also applies to the case of multiple groups. Figure 15A In the case where the common drive appropriate signal 300 is not received, only the first energy generating element is selected and driven, and the second energy generating element is not selected and driven. Figure 15B and Figure 15C As shown in the figure, when a shared drive signal 300 is received, if the first energy generating element is not selected, the second energy generating element is selected and driven. In this case, the first and second energy generating elements within the same independent flow path are driven exclusively. By setting the shared drive signal 300 as described above, the timing for driving the second energy generating element is established, thereby forming a circular flow. By periodically providing the shared drive signal 300, a periodic circular flow is formed, thereby achieving a continuous circulation effect.

[0109] exist Figure 15B In the case where none of the first energy generating elements is driven, the first energy generating element is not selected, and at this time, the second energy generating element is selected and driven. The case where none of the first energy generating elements is driven as described above corresponds to the case where a common drive appropriate signal 300 is provided between scans or between pages in a printing operation, for example. Figure 15C The diagram shows how Figure 15A In the case where the first energy generating elements are selected and driven in the same manner as above, when the respective first energy generating elements are not selected, the second energy generating elements are selected and driven in response to the common drive appropriateness signal 300. The case where the first energy generating elements are sporadically driven as described above corresponds to the case where the common drive appropriateness signal 300 is provided when printing characters or images, such as during scanning in a printing operation.

[0110] Although the drive pulse of the energy generating element is indicated by one pulse here, a drive pulse consisting of multiple (two or more) pulses may be used. In addition, the same drive pulse may be given to the first energy generating element and the second energy generating element, or different drive pulses may be used.

[0111] Here, as a comparison, a countermeasure for thickened ink in a liquid ejection head in which no circulating flow is formed will be described below. Examples of the countermeasures include a preliminary ejection operation of ejecting ink from an ejection hole and a suction operation of sucking ink from an ejection hole. For example, in a serial-type liquid ejection device, a preliminary ejection operation and / or a suction operation is performed before the head moves away from a cover provided for protecting the head at a head standby point to proceed to a printing operation. Alternatively, a preliminary ejection operation is performed in a non-printing area among the printing medium while the carriage reciprocates to perform a printing operation. Such an operation is performed at a timing different from that of the printing operation. In addition, in the case where the ink is prone to thickening, although it is added to the printing operation, the preliminary ejection operation is sometimes performed on the printing medium in the printing area during the reciprocating motion so as not to affect the image.

[0112] In this embodiment, by driving the second energy generating element to perform a circulation operation, the number of preparatory ejection operations and suction operations can be reduced. In this case, similarly, the circulation operation in the non-printing area during reciprocating motion or at the head standby point is performed at a timing different from the timing of the printing operation. Therefore, in this embodiment, the drive of the second energy generating element can be easily controlled using the appropriate drive signal 300 for the second energy generating element. In addition, in the case where the ink easily thickens, it is necessary to give priority to the ejection operation at a timing close to the timing of the printing operation during the circulation operation in the reciprocating printing area. On the other hand, by setting multiple timings or predetermined time periods for the circulation operation, it is not necessary to drive the circulation operation and the printing operation simultaneously. Therefore, in this embodiment, when the first energy generating element side is selected, by driving the first energy generating element, the circulation operation can be appropriately controlled without any impact on the printing operation.

[0113] As described so far, the second energy generating element is controlled to be driven according to the drive data and drive appropriate signal of the first energy generating element. Therefore, since it is not necessary to provide drive data for the second energy generating element, there is an advantage in that the amount of drive data can be reduced.

[0114] Even when a plurality of second energy generating elements are provided, the plurality of second energy generating elements can be controlled to be driven based on a common drive appropriate signal. Note that, although in this embodiment, the first energy generating element Ai and the second energy generating element Bi are controlled in a group of 32 elements (16 groups) in total (in the case of n=16), the total number of elements in each group can be various numbers such as 16 (8 groups) and 24 (12 groups).

[0115] Although in this embodiment, the drive appropriate signal 300 is described as being set for the substrate 18 and controlling the drive of the second energy generating element, the drive appropriate signal 300 can be set for the liquid ejection head outside the substrate or the liquid ejection device outside the liquid ejection head to control the drive of the second energy generating element.

[0116] Second embodiment

[0117] 10A to 10C Each is a schematic diagram illustrating in detail the vicinity of an ejection orifice of a liquid ejection head that ejects liquid such as ink in the second embodiment. Figure 10A This is a plan view when viewed from the side where the droplets are ejected from the ejection hole. Figure 10B and Figure 10C The diagram shows the Figure 10A Two examples of cross-sectional views taken along lines XB-XB and XC-XC in FIG.

[0118] although Figure 10B and Figure 10C Two examples are illustrated, but since the shape of the rear side of the substrate varies depending on the type of etching method used for the substrate, the cross section may have any of such shapes.

[0119] This embodiment differs from the first embodiment in that it employs a linear configuration, with the inlet and outlet of the individual flow paths separated. In this embodiment, the ends of the individual flow paths are positioned separately on opposite sides relative to a second direction that is orthogonal to the first direction in which the injection holes are arranged.

[0120] Adopting this configuration is advantageous in that, because the ink concentrated at the ejection hole portion does not return to the separate flow path along with the circulation flow due to separation of the inflow and outflow of the circulation flow in opposite directions, the influence of concentration is suppressed.

[0121] Third embodiment

[0122] Figures 11A to 11C Each is a schematic diagram illustrating in detail the vicinity of an ejection orifice of a liquid ejection head that ejects liquid such as ink in the third embodiment. Figure 11A It is a plan view when the droplet is ejected from the injection hole. Figure 10B and Figure 10C Same as in Figure 11B and Figure 11C The diagram shows the Figure 11A Two examples of cross-sectional views taken along lines XIB-XIB and XIC-XIC in FIG.

[0123] This embodiment differs from the second embodiment in that the number of injection hole arrays is doubled by providing three supply opening arrays, and each of the injection hole arrays is arranged on one side of the central supply opening array. In other words, the injection hole arrays are formed on both sides relative to the array direction of the multiple supply openings.

[0124] The advantage of adopting this configuration is that by adding one more array, the number of supply opening arrays increases from two to three, thereby doubling the number of injection hole arrays from one to two. As shown in the figure, an arrangement in which the spacing between the two injection hole arrays is offset is also possible. Furthermore, a configuration is possible that eliminates the need for wiring areas between the openings in the central supply opening array, thereby achieving high flexibility in the size and resolution of the openings in the central supply opening array. Consequently, this has the advantage of promoting high productivity by enabling faster nozzle refilling.

[0125] Note that in this embodiment, the three supply opening arrays are located at the same position in the inter-nozzle array direction, but each can be offset according to the nozzle position and the wiring layout between the openings. The same applies to the subsequent embodiments.

[0126] Fourth embodiment

[0127] Figure 12A and Figure 12B Each is a schematic diagram illustrating in detail the vicinity of an ejection orifice of a liquid ejection head that ejects liquid such as ink in the fourth embodiment. Figure 12A This is a plan view when viewed from the side where the droplets are ejected from the ejection hole. Figure 12B It is along Figure 12A A cross-sectional view taken along line XIIB-XIIB in FIG.

[0128] This embodiment differs from the third embodiment in that the direction of the circulation flow is reversed by disposing the injection hole arrays on both sides close to the respective supply opening arrays and disposing the second energy generating element close to the central supply opening array.

[0129] This configuration has the advantage that, because the concentrated ink near the ejection orifice is divided and discharged into the supply opening arrays on both sides, the influence of the concentrated ink when it flows back to the individual flow paths during the ejection is suppressed. Another advantage is that, because the ejection orifice arrays are arranged separately from each other, the influence of interference caused by the vibration of the meniscus accompanying the ejection from each ejection orifice is suppressed.

[0130] Fifth embodiment

[0131] Figure 13A and Figure 13B Each is a schematic diagram illustrating in detail the vicinity of an ejection orifice of a liquid ejection head that ejects liquid such as ink in the fifth embodiment. Figure 13A This is a plan view when viewed from the side where the droplets are ejected from the ejection hole. Figure 13B It is along Figure 13A A cross-sectional view taken along line XIIIB-XIIIB in FIG.

[0132] This embodiment differs from the third embodiment in that the direction of the circulating flow is reversed by disposing the second energy generating element close to the first energy generating element and by disposing the second energy generating element closer to the central supply opening array than the supply openings on both sides.

[0133] The advantage of adopting this configuration is that, as with the third embodiment, high productivity is facilitated by faster refilling due to the high flexibility in the size and resolution of the central supply opening array, and another advantage is that because the ink concentrated near the ejection hole is discharged into the supply opening arrays on both sides when being divided, the influence of the concentrated ink when it flows back to a separate flow path as the ejection is carried out is suppressed.

[0134] Sixth embodiment

[0135] 14A to 14C Each is a schematic diagram illustrating in detail the vicinity of an ejection orifice of a liquid ejection head that ejects liquid such as ink in the sixth embodiment. Figure 14A This is a plan view when viewed from the side where the droplets are ejected from the ejection hole. Figure 14B and Figure 14C Along the Figure 14A A cross-sectional view taken along lines XIVB-XIVB and XIVC-XIVC.

[0136] This embodiment differs from the first embodiment in that a staggered arrangement is employed for the injection hole arrays on the left and right sides of the supply groove, and a filter is also provided at the entrance of the separate flow path (near the second energy generating element). Even with this configuration, the effects of the present invention can be achieved in a similar manner.

[0137] While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments.The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

Claims

1. A liquid spraying method, comprising: A separate injection unit comprising a spray hole through which the liquid is sprayed, a pressure chamber, the pressure chamber being in communication with the injection hole, a first heat generating element provided for the pressure chamber and configured to generate heat energy for ejecting the liquid from the ejection hole, a separate flow path communicating with the pressure chamber, and a second heat generating element provided for the separate flow path; and A liquid ejection head including a common flow path for supplying liquid to a plurality of individual flow paths of a plurality of individual ejection units, wherein The first heat generating element and the second heat generating element are controlled to be driven under the following conditions: When the first heat generating element is driven, the second heat generating element is not driven, and When the first heat energy generating element is not driven, upon receiving a driving signal instructing driving of the second heat energy generating element, the second heat energy generating element is driven.

2. The liquid ejecting method according to claim 1, wherein The liquid ejection head includes a drive control unit configured to control driving of the first and second heat energy generating elements of the individual ejection units.

3. The liquid ejecting method according to claim 1, wherein The plurality of spray holes in the plurality of individual spray units form a spray hole array.

4. The liquid ejecting method according to claim 1, wherein: The plurality of individual flow paths of the plurality of individual spraying units and the common flow path are connected through an opening. The liquid ejecting method according to claim 3 , wherein: In the individual flow path of the individual ejection unit, the first heat energy generating element and the second heat energy generating element are disposed in a direction intersecting the ejection hole array. The liquid ejecting method according to claim 5 , wherein: The separate flow path extends in a direction intersecting the injection hole array such that both end portions of the separate flow path are positioned across the injection hole array.

7. The liquid ejecting method according to claim 6, wherein: One ends of the plurality of individual flow paths and the common flow path are connected through a plurality of first openings arranged along the spray hole array, and the other ends of the plurality of individual flow paths and the common flow path are connected through a plurality of second openings arranged along the spray hole array. The liquid ejecting method according to claim 7 , wherein: The first spray hole array and the second spray hole array are formed on both sides with respect to an array direction of the plurality of second openings.

9. The liquid ejecting method according to claim 8, wherein: In the plurality of individual flow paths, the plurality of first heat generating elements are disposed on a side close to the plurality of second openings.

10. The liquid ejecting method according to claim 8, wherein In the plurality of separate flow paths, a plurality of second heat generating elements are disposed on a side close to the plurality of second openings.

11. The liquid ejecting method according to claim 3, wherein: In at least one individual flow path among the plurality of individual flow paths, the first heat generation element and the second heat generation element are disposed along the injection hole array.

12. The liquid ejecting method according to claim 11, wherein Both end portions of the individual flow paths are positioned on one side relative to the injection hole array.

13. The liquid ejecting method according to claim 1, wherein The plurality of second heat generating elements are controlled to be driven by using a common driving signal.

14. A liquid ejecting head, comprising: a spray hole through which liquid is sprayed; a pressure chamber, the pressure chamber being in communication with the injection hole; a first heat generating element provided with respect to the pressure chamber and configured to generate heat energy for ejecting liquid from the ejection hole; a separate flow path communicating with the pressure chamber; a second heat generating element provided for the separate flow path; as well as a driving circuit configured to control driving of the first heat generating element and the second heat generating element, wherein The driving circuit includes a first switch capable of switching the first heat generating element and the second heat generating element exclusively with each other so as to bring only either one of the first heat generating element and the second heat generating element into a drivable state, and a second switch capable of switching between a drive-enabled state and a drive-disabled state in the second heat generating element.

15. The liquid ejecting head according to claim 14, wherein In the driving circuit, the second switch is provided closer to the second heat generating element than the first switch.

Images