Liquid ejection head and liquid ejection device

Abstract

To provide a liquid discharge head which can uniformly warm liquid in the vicinity of a nozzle and in a common liquid chamber, prevent liquid exposure of a heater and facilitates state confirmation and replacement of the heater.SOLUTION: A liquid discharge head comprises: a nozzle substrate 1 which has a nozzle 4 for discharging liquid; a common liquid chamber member 20 which forms a common liquid chamber 10 communicating to the nozzle 4; a head holding member 40 which stores at least a portion of the common liquid chamber member 20 and the nozzle substrate 1 in an opening 40a; a nozzle cover member 14 which contacts the peripheral edge of the opening 40a of the head holding member 40 and the outer peripheral edge of a discharge surface of the nozzle substrate 1 and protects the nozzle substrate 1; a hollow head cover member 63 which contacts a surface on the common liquid chamber member side of the head holding member 40; heating means 42 which heats the liquid; and temperature detection means for controlling heating by the heating means 42. A recess 41 is provided in at least a portion of the side surface of the head holding member 40 and the heating means 42 is stored in the recess 41.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a liquid ejection head and a device for ejecting liquid. [Background technology]

[0002] BACKGROUND ART Image forming devices such as printers, facsimiles, copiers, plotters, and combination machines thereof are known that are equipped with a liquid ejection head that ejects droplets of ink or other liquid, and that are equipped with a device that ejects liquid to form an image on a recording medium. A liquid ejection head uses a piezoelectric element or other piezoelectric material to generate pressure fluctuations in a pressure chamber (also called an ink flow path, liquid chamber, etc.) that communicates with the nozzle, thereby ejecting liquid droplets from the nozzle hole.

[0003] In liquid ejection heads, there are cases where highly viscous ink is used, or where the viscosity of the ink increases due to temperature. In such cases, sufficient ejection of droplets may not be possible, which may affect image quality. To address this issue, a technology has been proposed in which a heater or the like is provided in the liquid ejection head to heat the ink (see, for example, Patent Document 1).

[0004] When a heater is provided in a liquid ejection head, there is a problem in that the temperature of the ink may vary between the vicinity of the nozzle and the common liquid chamber depending on the heater's installation position and the difference in thermal conductivity of the surrounding members. In response to this, Patent Document 1 discloses a configuration that can effectively heat the ink near the nozzles and the ink inside the head chip, by providing a heat-conducting member that is in contact with both the common liquid chamber and the vicinity of the nozzles, in order to eliminate temperature unevenness near the nozzles and make the ink temperature near the common liquid chamber and the nozzles uniform. Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, UV ink is an example of ink that heats up when ejected from a liquid ejection head. It is known that the ignition temperature of UV ink is approximately 340°C. Therefore, if the heater becomes uncontrollable and the rated voltage is applied, causing a runaway state, the ink may heat up above its ignition temperature. In particular, if ink adheres to the heater, the risk of ignition increases, so it is necessary to protect the heater from exposure to ink.

[0006] On the other hand, in a liquid ejection head equipped with a heater, if an abnormality occurs in the heater performance, it is required that the status of the heater be checked and the heater be replaced easily.If the structure requires difficult disassembly work to check or replace the heater, it becomes necessary to replace the entire liquid ejection head, which poses a problem of a heavy burden on the user.

[0007] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a liquid ejection head that can uniformly heat the liquid near the nozzles and in the common liquid chamber, prevents the heater from being exposed to the liquid, and makes it easy to check the condition of the heater and replace it. [Means for solving the problem]

[0008] In order to solve the above problems, the liquid ejection head of the present invention comprises a nozzle substrate having nozzles for ejecting liquid, a common liquid chamber member forming a common liquid chamber communicating with the nozzles, a head holding member having an opening and accommodating at least a part of the common liquid chamber member and the nozzle substrate in the opening, a nozzle cover member that abuts against the periphery of the opening of the head holding member and the outer periphery of the ejection surface of the nozzle substrate and protects the nozzle substrate, a hollow head cover member that abuts against the surface of the head holding member facing the common liquid chamber member, heating means that heats the liquid, and temperature detection means for controlling the heating by the heating means, outer The heating device is characterized in that a recess is provided in at least a part of the side surface, and the heating means is housed in the recess. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a liquid ejection head that can uniformly heat the liquid near the nozzles and in the common liquid chamber, prevents the heater from being exposed to the liquid, and makes it easy to check the status of the heater and replace it. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a schematic cross-sectional view of a liquid ejection head according to an embodiment of the present invention. [Figure 2] 10A and 10B are explanatory diagrams showing heat conduction from the head holding member to the common liquid chamber member. [Figure 3] 2 is a schematic plan view of the liquid ejection head of FIG. 1, viewed from below. [Figure 4] FIG. 1 is an explanatory diagram schematically illustrating a main part of a liquid ejection head according to an embodiment of the present invention. [Figure 5] FIG. 2 is a schematic cross-sectional view of an example of a liquid ejection head. [Figure 6] FIG. 10 is another schematic cross-sectional view of the example of the liquid ejection head. [Figure 7] FIG. 10 is a schematic cross-sectional view of another example of a liquid ejection head. [Figure 8] FIG. 10 is a schematic perspective view of another example of a liquid ejection head. [Figure 9] FIG. 1 is a schematic diagram of an example of a device for discharging liquid. [Figure 10] FIG. 2 is a schematic diagram of an example of a head unit. [Figure 11] FIG. 1 is a block diagram illustrating an example of a liquid circulation device. [Figure 12] FIG. 10 is a schematic diagram of another example of a device for discharging liquid. [Figure 13] FIG. 10 is a schematic diagram of another example of a device for discharging liquid. [Figure 14] FIG. 2 is a schematic diagram of an example of a liquid ejection unit. [Figure 15] FIG. 10 is a schematic diagram of another example of the liquid ejection unit. DETAILED DESCRIPTION OF THE INVENTION

[0011] The liquid ejection head and liquid ejection device of the present invention will be described below with reference to the drawings. Note that the present invention is not limited to the following embodiments, and other modifications, additions, corrections, deletions, and other changes can be made within the scope of what a person skilled in the art can conceive. Any aspect is within the scope of the present invention as long as it achieves the functions and effects of the present invention.

[0012] An embodiment of a liquid ejection head according to the present invention will be described with reference to FIGS. Fig. 1 is a cross-sectional schematic diagram of a liquid ejection head according to this embodiment, taken in a direction perpendicular to the nozzle arrangement direction. Fig. 2 is an explanatory diagram schematically illustrating heat conduction in the liquid ejection head shown in Fig. 1. Fig. 3 is a plan view of the liquid ejection head of Fig. 1, viewed from below. Fig. 4 is an explanatory diagram schematically illustrating the main parts of the liquid ejection head, taken in a side view along the nozzle arrangement direction.

[0013] The liquid ejection head of this embodiment comprises a nozzle substrate 1 having nozzles 4 that eject liquid, a common liquid chamber member 20 that forms a common liquid chamber 10 that communicates with the nozzles 4, a head holding member 40 that has an opening 40a and accommodates at least a portion of the common liquid chamber member 20 and the nozzle substrate 1 in the opening 40a, a nozzle cover member 14 that abuts against the periphery of the opening 40a of the head holding member 40 and the outer periphery of the ejection surface of the nozzle substrate 1 and protects the nozzle substrate 1, a hollow head cover member 63 that abuts against the surface of the head holding member 40 facing the common liquid chamber member, a heating means (hereinafter also referred to as a "heater") 42 that heats the liquid, and a temperature detection means for controlling the heating by the heating means 42. A recess 41 is provided on at least a part of the side surface of the head holding member 40, and the recess 41 houses a heating means 42.

[0014] The recess 41 that serves as the heater accommodating portion is preferably provided on both opposing side surfaces of the head holding member 40. It is difficult to access the heater 42 on the surface (lower surface) of the head holding member 40 facing the nozzle substrate 1, and there is a risk of exposure to liquid on the surface (upper surface) facing the common liquid chamber member 20. Furthermore, the heating means (heater) 42 is preferably disposed on the innermost surface of the recess 41 so as to abut against the head holding member 40 inside the recess 41. By disposing the heaters 42 symmetrically, the liquid can be heated uniformly via the head holding member 40.

[0015] In FIG. 2, the heat conduction from the heater 42 is schematically indicated by arrows. 2, there are two paths through which heat is transmitted: (1) a first path in which heat is transmitted from the heater 42 via the head holding member 40 to the common liquid chamber member 20, thereby heating the liquid, and (2) a second path in which heat is transmitted from the heater 42 via the head holding member 40 to the nozzle cover member 14 and further to the nozzle substrate 1, thereby heating the liquid. This type of heat conduction allows the liquid to be heated efficiently and uniformly.

[0016] In the liquid ejection head of this embodiment, the nozzle cover member 14 and the head holding member 40 are preferably made of a material with high thermal conductivity, such as stainless steel. Similarly, the nozzle substrate 1 is preferably made of a material with high heat transfer rate and excellent thermal conductivity, for example, a silicon material with higher thermal conductivity than stainless steel.

[0017] Furthermore, it is preferable that the thermal conductivity of the material that constitutes the head holding member 40 be greater than the thermal conductivity of the material that constitutes the common liquid chamber member 20 . The head holding member 40 does not have a complicated shape and can be easily manufactured from a material with high thermal conductivity.

[0018] It is preferable that the Young's modulus of the material that constitutes the head holding member 40 is greater than the Young's modulus of the material that constitutes the common liquid chamber member 20. Ensuring rigidity with the head holding member 40 can increase the robustness of the head.

[0019] In a configuration including a nozzle substrate 1 made of silicon material, and a nozzle cover member 14 and a head holding member 40 made of stainless steel, the heat conduction path shown in FIG. 2 has a particularly large heating effect via the second path, which is heated from the nozzle substrate side.

[0020] FIG. 3 is a schematic plan view of the liquid ejection head as seen from the ejection surface side of the nozzle substrate 1. As shown in FIG. As shown in FIG. 3, the nozzle cover member 14 has an abutting portion 14a that abuts against the periphery of the opening of the head holding member 40, and an abutting portion 14b that abuts against the outer periphery of the ejection surface of the nozzle substrate 1. The larger the area of ​​the contact portions (14a, 14b), the more easily the heat from the heater 42 is transferred to the liquid.

[0021] The nozzle substrate 1 has a rectangular or parallelogram shape in plan view when viewed from the ejection surface, and it is preferable that at least one side of the periphery abuts on the nozzle cover member 14 and is in close contact with it. The method for tightly adhering the nozzle cover member 14 to the head holding member 40 and the nozzle substrate 1 is not particularly limited, but examples include bonding with an adhesive, bonding with a fastening member such as a screw via a gasket, and bonding by welding.

[0022] FIG. 4 is an explanatory diagram that schematically shows the external appearance of the main part of the liquid ejection head according to this embodiment. The liquid ejection head of this embodiment can protect the heater 42 from exposure to liquid by accommodating the heater 42 within the recess 41 of the head holding member 40, but as shown in Figure 4, by providing a covering member 44 that covers the opening of the recess 41, the heater 42 can be protected more reliably.

[0023] The method for attaching the covering member 44 to the head holding member 40 is not particularly limited, but it is preferable that the covering member 44 be easily detachable, for example, by using screws. For example, as shown in Fig. 4, screw holes 46 are provided on the head holding member 40 side (screw hole 46a) and the covering member 44 side (screw hole 46b), and the covering member 44 can be engaged and fixed using screw members (not shown).

[0024] Furthermore, it is preferable to provide a seal member 43 between the head holding member 40 and the covering member 44 to seal the opening of the recess 41. The seal member 43 may be a packing or the like. By sealing the recess 41 with the covering member 44 and the sealing member 43, it is possible to prevent liquid from adhering to the heater 42 housed inside, and also to reduce the risk of fire due to runaway of the heater 42.

[0025] The head holding member 40 preferably has through holes 45 that penetrate from the recess 41 to the surface, and wiring 70 of the heating means (heater) is preferably inserted through the through holes 45. By providing the through-holes 45, the covering member 44 does not obstruct the wiring 70.

[0026] The liquid ejection head of this embodiment is provided with a temperature detection means, and is capable of controlling the heating by the heater 42 via a control means in accordance with the detected temperature. The temperature detection means is not particularly limited as long as it can measure the temperature of the liquid directly or indirectly. The temperature detection means may be disposed in the recess 41 together with the heater 42.

[0027] According to the liquid ejection head of this embodiment, the liquid near the nozzle 4 and in the common liquid chamber 10 can be heated efficiently and uniformly, the heating means (heater) 42 is prevented from being exposed to the liquid (ink), and the condition of the heater 42 can be easily checked and replaced.

[0028] Hereinafter, other embodiments of the liquid ejection head to which the configuration according to the present invention is applied will be described. FIG. 5 is a cross-sectional explanatory view taken along a direction (longitudinal direction of pressure chambers) perpendicular to the nozzle arrangement direction of the liquid ejection head according to the embodiment, and FIG. 6 is a cross-sectional explanatory view taken along the nozzle arrangement direction.

[0029] The liquid ejection head 100 is formed by laminating and bonding a nozzle substrate 1 having a piezoelectric body, a flow path plate 2 which is an individual flow path member, and a vibration plate member 3 which serves as a wall member. The liquid ejection head 100 also includes a common flow path member 20 which also serves as a frame member for the head. The liquid ejection head 100 may further include a piezoelectric actuator 11 which displaces a vibration region (vibration plate) 30 of the vibration plate member 3.

[0030] The nozzle substrate 1 has a plurality of nozzles 4 that eject liquid. The flow path plate 2 has a plurality of pressure chambers 6 that communicate with a plurality of nozzles 4, individual supply flow paths 7 that are individual flow paths that communicate with each pressure chamber 6, and an intermediate supply flow path 8 that serves as a liquid introduction section that communicates with one or more (one in this embodiment) individual supply flow paths 7.

[0031] The vibration plate member 3 has a plurality of displaceable vibration plates (vibration regions) 30 that form the wall surfaces of the pressure chambers 6 of the flow path plate 2. Here, the vibration plate member 3 has a two-layer structure (not limited to this) and is composed of a first layer 3A that forms a thin portion from the flow path plate 2 side and a second layer 3B that forms a thick portion.

[0032] The first layer 3A, which is a thin portion, forms a deformable vibration region 30 in a portion corresponding to the pressure chamber 6. Within the vibration region 30, the second layer 3B forms a convex portion 30a, which is a thick portion that is bonded to the piezoelectric actuator 11.

[0033] On the opposite side of the diaphragm member 3 to the pressure chamber 6, a piezoelectric actuator 11 including an electromechanical conversion element is arranged as a driving means (actuator means, pressure generating means) for deforming the vibration region 30 of the diaphragm member 3.

[0034] This piezoelectric actuator 11 is formed by forming grooves by half-cut dicing in a piezoelectric member bonded to a base member 13, and forming a required number of columnar piezoelectric elements 12 in a comb-like shape at specified intervals in the nozzle arrangement direction. The piezoelectric elements 12 are then bonded to protrusions 30a, which are thick portions formed in the vibration region 30 of the vibration plate member 3.

[0035] This piezoelectric element 12 is formed by alternately laminating piezoelectric layers and internal electrodes, and the internal electrodes are drawn out to the end surfaces and connected to external electrodes (end surface electrodes), and flexible wiring member 15 is connected to the external electrodes.

[0036] The common flow path member 20 forms a common liquid chamber (hereinafter also referred to as a "common supply flow path") 10 that communicates with the multiple pressure chambers 6. The common supply flow path 10 communicates with an intermediate supply flow path 8 that serves as a liquid introduction section via an opening 9 provided in the vibration plate member 3, and communicates with the individual supply flow paths 7 via the intermediate supply flow path 8.

[0037] In this liquid ejection head 100, for example, by lowering the voltage applied to the piezoelectric element 12 from a reference potential (intermediate potential), the piezoelectric element 12 contracts, the vibration area 30 of the vibration plate member 3 is pulled, and the volume of the pressure chamber 6 expands, causing liquid to flow into the pressure chamber 6.

[0038] Thereafter, the voltage applied to the piezoelectric element 12 is increased to expand the piezoelectric element 12 in the stacking direction, and the vibration region 30 of the vibration plate member 3 is deformed in the direction toward the nozzle 4, thereby contracting the volume of the pressure chamber 6, thereby pressurizing the liquid in the pressure chamber 6 and ejecting the liquid from the nozzle 4.

[0039] Fig. 7 is a cross-sectional explanatory view taken along a direction (longitudinal direction of pressure chambers) perpendicular to the nozzle arrangement direction of a liquid ejection head according to still another embodiment. Fig. 8 is a schematic perspective view of the liquid ejection head according to this embodiment.

[0040] The liquid ejection head 100 of this embodiment is a circulation type liquid ejection head, and is formed by laminating and bonding a nozzle substrate 1, a flow path plate 2, and a diaphragm member 3 serving as a wall member. It also includes a piezoelectric actuator 11 that displaces a vibration region (diaphragm) 30 of the diaphragm member 3, and a common liquid chamber member (hereinafter also referred to as a "common flow path member") 20 that also serves as a frame member for the head.

[0041] The flow path plate 2 has formed therein a plurality of pressure chambers 6 each connected to a plurality of nozzles 4 via a nozzle connecting passage 5, a plurality of individual supply flow paths 7 each connected to the plurality of pressure chambers 6 and also serving as fluid resistance sections, and one or more intermediate supply flow paths 8 serving as liquid introduction sections connected to two or more individual supply flow paths 7.

[0042] As in the above embodiment, the individual supply flow path 7 includes two flow path sections, a first flow path section 7A and a second flow path section 7B, which have higher fluid resistance than the pressure chamber 6, and a first flow path section 7A and a second flow path section 7B. and a third flow path section 7C that has lower fluid resistance than the first flow path section 7A and the second flow path section 7B.

[0043] The flow path plate 2 is formed by stacking a plurality of plate-like members 2A to 2E, but is not limited to this.

[0044] In addition, the flow path plate 2 forms a plurality of individual recovery flow paths 57 along the surface direction of the flow path plate 2, each of which is connected to a plurality of pressure chambers 6 via a nozzle connecting passage 5, and an intermediate recovery flow path 58 which serves as one or more liquid discharge sections connected to two or more individual recovery flow paths 57.

[0045] The individual recovery flow path 57 includes two flow path sections, a first flow path section 57A and a second flow path section 57B, which have higher fluid resistance than the pressure chamber 6, and a third flow path section 57C, which is disposed between the first flow path section 57A and the second flow path section 57B and has lower fluid resistance than the first flow path section 57A and the second flow path section 57B. The individual recovery flow path 57 has a flow path section 57D, which is downstream of the second flow path section 57B in the circulation direction, and which has the same flow path width as the third flow path section 57C.

[0046] The common flow path member 20 forms a common supply flow path 10 and a common recovery flow path 50. In this embodiment, the common supply flow path 10 is made up of a flow path portion 10A that is aligned with the common recovery flow path 50 in the nozzle arrangement direction, and a flow path portion 10B that is not aligned with the common recovery flow path 50.

[0047] The common supply flow path 10 communicates with an intermediate supply flow path 8, which serves as a liquid introduction portion, via an opening 9 provided in the vibration plate member 3, and communicates with the individual supply flow paths 7 via the intermediate supply flow path 8. The common recovery flow path 50 communicates with an intermediate recovery flow path 58, which serves as a liquid discharge portion, via an opening 59 provided in the vibration plate member 3, and communicates with the individual recovery flow paths 57 via the intermediate recovery flow path 58.

[0048] In addition, the common supply flow path 10 communicates with a supply port 71 , and the common recovery flow path 50 communicates with a recovery port 72 .

[0049] The other layer configurations of the diaphragm member 3 and the configuration of the piezoelectric actuator 11 are the same as those in the above embodiment.

[0050] In this liquid ejection head 100, as in the above embodiment, the piezoelectric element 12 is stretched in the stacking direction, and the vibration area 30 of the vibration plate member 3 is deformed in the direction toward the nozzle 4, thereby contracting the volume of the pressure chamber 6, thereby pressurizing the liquid in the pressure chamber 6 and ejecting the liquid from the nozzle 4.

[0051] Furthermore, liquid that is not ejected from the nozzles 4 passes through the nozzles 4 and is recovered from the individual recovery flow path 57 to the common recovery flow path 50, and is then supplied again from the common recovery flow path 50 to the common supply flow path 10 via an external circulation path. Furthermore, even when liquid is not being ejected from the nozzles 4, the liquid circulates from the common supply flow path 10 to the common recovery flow path 50 via the pressure chamber 6, and is then supplied again to the common supply flow path 10 via an external circulation path.

[0052] In this embodiment as well, the pressure fluctuations caused by the liquid ejection can be attenuated and propagation to the common supply channel 10 and the common recovery channel 50 can be suppressed with a simple configuration.

[0053] [Liquid ejection device] A liquid ejection device according to the present invention includes the above-described ejection head according to the present invention. An example of a liquid ejection device according to the present invention will be described with reference to FIGS. FIG. 9 is a schematic explanatory diagram of the device, and FIG. 10 is a plan explanatory diagram of an example of a head unit of the device.

[0054] The printing device 500, which is a device for ejecting this liquid, includes an input means 501 for feeding a continuous body 510, a guide and conveying means 503 for guiding and conveying the continuous body 510, such as continuous paper or sheet material, fed from the input means 501 to a printing means 505, the printing means 505 for ejecting liquid onto the continuous body 510 to print and form an image, a drying means 507 for drying the continuous body 510, and an ejection means 509 for ejecting the continuous body 510.

[0055] The continuous body 510 is fed from the original winding roller 511 of the carrying-in means 501 , guided and conveyed by the rollers of the carrying-in means 501 , the guide and conveying means 503 , the drying means 507 and the carrying-out means 509 , and wound up by the winding roller 591 of the carrying-out means 509 .

[0056] In the printing means 505, this continuum 510 is transported on a transport guide member 559 opposite the head unit 550 and head unit 555, an image is formed by liquid ejected from the head unit 550, and post-processing is performed by processing liquid ejected from the head unit 555.

[0057] Here, in the head unit 550, for example, full line type head arrays 551A, 551B, 551C, and 551D (hereinafter referred to as "head array 551" when no distinction is made between colors) for four colors are arranged from the upstream side in the transport direction.

[0058] Each head array 551 is a liquid ejection means, and ejects liquid of black K, cyan C, magenta M, or yellow Y onto the conveyed continuum 510. Note that the types and numbers of colors are not limited to these.

[0059] The head array 551 is, for example, a liquid ejection head (also simply referred to as a "head") 100 according to the present invention arranged in a staggered pattern on a base member 552, but is not limited to this.

[0060] The liquid ejection head and liquid ejection device according to the present invention may be configured to circulate the liquid, and may be, for example, a liquid circulation device using the liquid ejection head. An example of a liquid circulation device will be described with reference to Fig. 11. Fig. 11 is a block diagram of the circulation device. Note that although only one head is shown here, when multiple heads are arranged, the supply side and recovery side liquid paths will be connected to the supply side and recovery side of the multiple heads, respectively, via a manifold or the like.

[0061] The liquid circulation device 600 is composed of a supply tank 601, a recovery tank 602, a main tank 603, a first liquid supply pump 604, a second liquid supply pump 605, a compressor 611, a regulator 612, a vacuum pump 621, a regulator 622, a supply side pressure sensor 631, and a recovery side pressure sensor 632.

[0062] Here, the compressor 611 and the vacuum pump 621 constitute a means for generating a pressure difference between the pressure in the supply tank 601 and the pressure in the recovery tank 602 .

[0063] The supply-side pressure sensor 631 is located between the supply tank 601 and the head 100, and is connected to a supply-side liquid path connected to the supply port 71 of the head 100. The recovery-side pressure sensor 632 is located between the head 100 and the recovery tank 602, and is connected to a recovery-side liquid path connected to the recovery port 72 of the head 100.

[0064] One side of the recovery tank 602 is connected to the supply tank 601 via a first liquid feed pump 604 , and the other side of the recovery tank 602 is connected to the main tank 603 via a second liquid feed pump 605 .

[0065] As a result, liquid flows into the head 100 from the supply tank 601 through the supply port 71, is recovered from the recovery port 72 to the recovery tank 602, and the liquid is sent from the recovery tank 602 to the supply tank 601 by the first liquid supply pump 604, thereby forming a circulation path through which the liquid circulates.

[0066] Here, a compressor 611 is connected to the supply tank 601 and is controlled so that a predetermined positive pressure is detected by a supply-side pressure sensor 631. On the other hand, a vacuum pump 621 is connected to the recovery tank 602 and is controlled so that a predetermined negative pressure is detected by a recovery-side pressure sensor 632.

[0067] This allows the liquid to circulate through the head 100 while maintaining a constant negative pressure at the meniscus.

[0068] Furthermore, when liquid is ejected from the nozzles 4 of the head 100, the amount of liquid in the supply tank 601 and the recovery tank 602 decreases. Therefore, the second liquid feed pump 605 is used to replenish the liquid from the main tank 603 to the recovery tank 602 as needed.

[0069] The timing of replenishing the liquid from the main tank 603 to the recovery tank 602 can be controlled based on the detection results of a liquid level sensor installed in the recovery tank 602, such as replenishing the liquid when the liquid level in the recovery tank 602 drops below a predetermined level.

[0070] Next, another example of a printing device as a device for ejecting liquid according to the present invention will be described with reference to Figures 12 and 13. Figure 12 is an explanatory plan view of the main parts of the device, and Figure 13 is an explanatory side view of the main parts of the device.

[0071] This printing device 500 is a serial type device, and a carriage 403 is moved back and forth in the main scanning direction by a main scanning movement mechanism 493. The main scanning movement mechanism 493 includes a guide member 401, a main scanning motor 405, a timing belt 408, etc. The guide member 401 is hung between left and right side plates 491A and 491B, and movably holds the carriage 403. The main scanning motor 405 then moves the carriage 403 back and forth in the main scanning direction via a timing belt 408 hung between a drive pulley 406 and a driven pulley 407.

[0072] This carriage 403 is equipped with a liquid ejection unit 440 that integrates a liquid ejection head 100 and a head tank 441. The liquid ejection head 100 of the liquid ejection unit 440 ejects liquid of each color, for example, yellow (Y), cyan (C), magenta (M), and black (K). The liquid ejection head 100 is mounted with a nozzle row made up of multiple nozzles arranged in a sub-scanning direction perpendicular to the main scanning direction, and the ejection direction facing downward.

[0073] The liquid ejection head 100 is connected to the liquid circulation device 600 described above, and liquid of a desired color is circulated and supplied.

[0074] This printing apparatus 500 is equipped with a transport mechanism 495 for transporting paper 410. The transport mechanism 495 includes a transport belt 412, which is a transport means, and a sub-scanning motor 416 for driving the transport belt 412.

[0075] The conveyor belt 412 attracts the paper 410 and conveys it at a position facing the liquid ejection head 100. The conveyor belt 412 is an endless belt that is stretched between a conveyor roller 413 and a tension roller 414. The paper can be attracted by electrostatic attraction or air suction.

[0076] The conveyor belt 412 moves in a circular motion in the sub-scanning direction when the conveyor roller 413 is rotationally driven by a sub-scanning motor 416 via a timing belt 417 and a timing pulley 418 .

[0077] Furthermore, a maintenance and recovery mechanism 420 for performing maintenance and recovery of the liquid ejection head 100 is disposed on one side of the conveyor belt 412 on one side of the carriage 403 in the main scanning direction.

[0078] The maintenance and recovery mechanism 420 is made up of, for example, a cap member 421 that caps the nozzle surface (the surface on which the nozzles are formed) of the liquid ejection head 100, a wiper member 422 that wipes the nozzle surface, and the like.

[0079] The main scanning movement mechanism 493, the maintenance and recovery mechanism 420, and the transport mechanism 495 are attached to a housing including side plates 491A and 491B and a back plate 491C.

[0080] In the printing device 500 configured in this manner, the paper 410 is fed onto the conveyor belt 412 and adsorbed thereon, and the paper 410 is conveyed in the sub-scanning direction by the circular movement of the conveyor belt 412.

[0081] Therefore, by driving the liquid ejection head 100 in accordance with an image signal while moving the carriage 403 in the main scanning direction, liquid is ejected onto the stationary paper 410 to form an image.

[0082] [Liquid ejection unit] Next, an example of a liquid ejection unit equipped with a liquid ejection head according to the present invention will be described with reference to Fig. 14. Fig. 14 is an explanatory plan view of the main part of the unit.

[0083] This liquid ejection unit 440 is composed of the components that make up the above-mentioned liquid ejection device, including a housing portion consisting of side plates 491A, 491B and a back plate 491C, a main scanning movement mechanism 493, a carriage 403, and a liquid ejection head 100.

[0084] It is also possible to configure a liquid discharge unit in which the above-described maintenance and recovery mechanism 420 is further attached to, for example, the side plate 491B of this liquid discharge unit 440.

[0085] Next, still another example of the liquid discharge unit will be described with reference to Fig. 15. Fig. 15 is an explanatory front view of the unit.

[0086] This liquid ejection unit 440 is composed of a liquid ejection head 100 to which a flow path part 444 is attached, and a tube 456 connected to the flow path part 444 .

[0087] The flow path part 444 is disposed inside the cover 442. A head tank 441 may be included instead of the flow path part 444. A connector 443 for electrically connecting with the liquid ejection head 100 is provided on the upper part of the flow path part 444.

[0088] In the present application, the liquid to be ejected may have a viscosity and surface tension that allows it to be ejected from the head, and is not particularly limited, but it is preferable that the viscosity of the liquid be 30 mPa·s or less at room temperature and normal pressure, or by heating or cooling. More specifically, the liquid may be a solution, suspension, emulsion, etc. containing a solvent such as water or an organic solvent, a colorant such as a dye or a pigment, a functionalizing material such as a polymerizable compound, a resin, or a surfactant, a biocompatible material such as DNA, amino acids, proteins, or calcium, an edible material such as a natural dye, etc., and these may be used, for example, in inkjet inks, surface treatment liquids, components of electronic elements or light-emitting elements, and resist patterns for electronic circuits. It can be used as a forming liquid, a material liquid for three-dimensional modeling, etc.

[0089] Energy sources for ejecting liquid include piezoelectric actuators (laminated piezoelectric elements and thin-film piezoelectric elements), thermal actuators that use electrothermal conversion elements such as heating resistors, and electrostatic actuators consisting of a vibration plate and an opposing electrode.

[0090] A "liquid ejection unit" is a liquid ejection head integrated with functional parts and mechanisms, and includes a collection of parts related to ejecting liquid. For example, a "liquid ejection unit" includes a liquid ejection head combined with at least one of the following components: a head tank, a carriage, a supply mechanism, a maintenance and recovery mechanism, a main scanning movement mechanism, and a liquid circulation device.

[0091] Here, "integrated" includes, for example, a liquid ejection head and a functional part or mechanism that are fixed to each other by fastening, bonding, engaging, etc., or one that is held movably relative to the other. The liquid ejection head, functional part, or mechanism may also be configured to be detachable from each other.

[0092] For example, some liquid ejection units have a liquid ejection head and a head tank integrated together, while others have a liquid ejection head and a head tank integrated together by being connected to each other by a tube, etc. Here, a unit including a filter can be added between the head tank and the liquid ejection head of these liquid ejection units.

[0093] Furthermore, there is a liquid ejection unit in which the liquid ejection head and the carriage are integrated.

[0094] In some liquid ejection units, the liquid ejection head is movably held by a guide member that constitutes part of the scanning movement mechanism, and the liquid ejection head and the scanning movement mechanism are integrated together. In other liquid ejection units, the liquid ejection head, the carriage, and the main scanning movement mechanism are integrated together.

[0095] Furthermore, there is a liquid ejection unit in which a cap member, which is part of the maintenance and recovery mechanism, is fixed to a carriage on which a liquid ejection head is attached, thereby integrating the liquid ejection head, carriage, and maintenance and recovery mechanism.

[0096] In some liquid ejection units, a tube is connected to a liquid ejection head equipped with a head tank or flow path components, integrating the liquid ejection head with a supply mechanism. Liquid is supplied from a liquid storage source to the liquid ejection head via this tube.

[0097] The main scanning movement mechanism includes the guide member alone, and the supply mechanism includes the tube alone and the loading unit alone.

[0098] "Liquid ejection devices" include devices that have a liquid ejection head or a liquid ejection unit and eject liquid by driving the liquid ejection head. Liquid ejection devices include not only devices that can eject liquid onto objects to which the liquid can adhere, but also devices that eject liquid into air or liquid.

[0099] This "liquid ejecting device" can also include means for feeding, transporting, and discharging items onto which liquid can be attached, as well as pre-processing devices and post-processing devices.

[0100] For example, examples of "liquid ejection devices" include image forming devices that eject ink to form images on paper, and machines that form powder into layers to create three-dimensional objects. There is a three-dimensional modeling device that ejects modeling liquid onto a formed powder layer.

[0101] Furthermore, the term "liquid ejection device" is not limited to devices that use ejected liquid to visualize meaningful images such as letters and figures. For example, it also includes devices that form patterns that have no meaning in themselves, and devices that create three-dimensional images.

[0102] The above-mentioned "object onto which a liquid can adhere" means an object onto which a liquid can adhere at least temporarily, an object onto which the liquid can adhere and stick, an object onto which the liquid can penetrate, etc. Specific examples include media such as paper, recording paper, film, and cloth, electronic circuit boards, electronic components such as piezoelectric elements, powder layers, organ models, and test cells, and unless otherwise specified, includes all objects onto which a liquid can adhere.

[0103] The material of the "substance to which a liquid can adhere" may be any material to which a liquid can adhere, even temporarily, such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, or ceramics.

[0104] Furthermore, the "liquid ejection device" may be a device in which a liquid ejection head and an object onto which liquid can be attached move relatively, but is not limited to this. Specific examples include a serial type device in which a liquid ejection head moves, and a line type device in which a liquid ejection head does not move.

[0105] Other examples of "liquid ejecting devices" include a treatment liquid application device that ejects a treatment liquid onto paper to apply the treatment liquid to the surface of the paper for purposes such as modifying the surface of the paper, and an injection granulation device that ejects a composition liquid in which raw materials are dispersed through a nozzle to granulate fine particles of the raw materials.

[0106] In the present application, the terms image formation, recording, printing, copying, printing, modeling, etc. are all synonymous. [Explanation of symbols]

[0107] 1 Nozzle board 4 nozzles 10 Common liquid chamber 14 Nozzle cover member 20 Common liquid chamber member 40 Head holding member 40a opening 41 Recess 42 Heating means (heater) 43 Sealing material 44 Covering material 45 through holes 60 Subtank 61 Ink Port 63 Head cover member 70 Wiring [Prior art documents] [Patent documents]

[0108] [Patent Document 1] International Publication No. WO2015 / 115353

Claims

1. a nozzle substrate having nozzles for ejecting liquid; a common liquid chamber member that forms a common liquid chamber that communicates with the nozzles; a head holding member having an opening and accommodating at least a part of the common liquid chamber member and the nozzle substrate in the opening; a nozzle cover member that abuts against a peripheral edge of the opening of the head holding member and an outer peripheral edge of the ejection surface of the nozzle substrate, and protects the nozzle substrate; a hollow head cover member that abuts against a surface of the head holding member on the side of the common liquid chamber member; a heating means for heating the liquid; a temperature detection means for controlling the heating by the heating means, A liquid ejection head, characterized in that a recess is provided on at least a part of the outer side surface of the head holding member, and the heating means is housed in the recess.

2. 2. The liquid ejection head according to claim 1, further comprising a covering member that covers the opening of the recess of the head holding member.

3. 3. The liquid ejection head according to claim 2, further comprising a seal member between the head holding member and the covering member for sealing the opening of the recess.

4. 4. A liquid ejection head according to claim 1, wherein the temperature detection means is disposed within the recess.

5. the head holding member has a through hole that penetrates from the recess to the surface, 5. A liquid ejection head according to claim 1, wherein wiring of the heating means is inserted through the through-hole.

6. 6. The liquid ejection head according to claim 1, wherein the nozzle substrate is made of a silicon material.

7. 7. The liquid ejection head according to claim 1, wherein the nozzle cover member and the head holding member are made of stainless steel.

8. 8. The liquid ejection head according to claim 1, wherein the thermal conductivity of the material that forms the head holding member is greater than the thermal conductivity of the material that forms the common liquid chamber member.

9. 9. The liquid ejection head according to claim 1, wherein the Young's modulus of the material that forms the head holding member is greater than the Young's modulus of the material that forms the common liquid chamber member.

10. A liquid ejection device comprising the liquid ejection head according to any one of claims 1 to 9.

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