SEALING MEMBER AND ITS MANUFACTURING METHOD, PRESSURE ADJUSTMENT MECHANISM, LIQUID DISCHARGE HEAD, AND LIQUID DISCHARGE APPARATUS

Abstract

To provide a seal member which is used as a valve etc. in a pressure adjustment mechanism, has a high strength base member, and achieves high reliability.SOLUTION: A seal member comprises: an elastic member (a valve part 407) having an annular contact part (a valve tip part 501), formed as an annular projection, and a base member (a lever part 503). The elastic member is fixed to the base member by holding a tube-like held part 505 extending from the annular contact part with an annular groove formed at the base member. A holding length 514, a length that the annular groove 535 holds the held part 505 along a depth direction of the base member, is set so as to be longer than a width 513 of the annular groove 535.SELECTED DRAWING: Figure 18

Description

[Technical field]

[0001] The present invention relates to a sealing member that can be used as a valve in a pressure adjustment mechanism, for example, and a manufacturing method thereof, as well as a pressure adjustment mechanism, a liquid ejection head, and a liquid ejection apparatus that use this sealing member. [Background technology]

[0002] Some liquid ejection devices, such as inkjet recording devices, have a function of circulating liquid within the device. When circulating liquid within the device, a pressure adjustment mechanism is provided to control the pressure of the circulating liquid. The liquid ejection device disclosed in Patent Document 1 is equipped with a back-pressure type pressure adjustment mechanism that maintains a constant back pressure. The back-pressure type pressure adjustment mechanism has a first pressure chamber fluidly sealed by a flexible member, a second pressure chamber provided downstream of the first pressure chamber, a valve that changes the flow resistance between the first pressure chamber and the second pressure chamber, and a pressure receiving plate that displaces according to the increase or decrease in the liquid in the first pressure chamber. The valve is provided within the first pressure chamber, and its valve body moves according to the displacement of the pressure receiving plate to change the flow resistance of the liquid flowing from the first pressure chamber to the second pressure chamber, thereby operating to maintain the function of maintaining the pressure of the first pressure chamber, i.e., the back pressure, constant. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-124620 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the pressure adjustment mechanism, the valve is configured as a seal member in which an elastic member that serves as a valve body is bonded to a base member that moves in response to the displacement of a pressure plate, but a large peeling force is applied between the elastic member and the base member. If the elastic member is bonded to the base member with an adhesive, sufficient reliability cannot be obtained, and when the valve is manufactured by assembling and molding the elastic member and the base member by two-color molding, it becomes difficult to use a high-strength material for the base member.

[0005] An object of the present invention is to provide a sealing member for use, for example, in a pressure adjustment mechanism, which has a high-strength base member and is highly reliable, as well as a manufacturing method for the same, and a pressure adjustment mechanism, a liquid ejection head, and a liquid ejection device that use the sealing member. [Means for solving the problem]

[0006] The sealing member of the present invention includes an elastic member having an annular contact portion formed as an annular protrusion, and a base member to which the elastic member is fixed, and the elastic member is fixed to the base member by a tubular held portion extending from the annular contact portion being held by an annular groove formed in the base member, and a holding length, which is a length by which the annular groove holds the held portion along the depth direction of the base member, is longer than the width of the annular groove, and the elastic member , covered The support member has a reinforcing portion extending from the holding portion, and at least a portion of the reinforcing portion is held by a groove formed in the base member.

[0007] The method for producing the seal member of the present invention is a method for producing the seal member of the present invention, which is characterized in that the elastic member and the base member are integrally assembled in a mold by injection molding.

[0008] The pressure adjustment mechanism of the present invention comprises a liquid storage chamber for storing liquid and having at least a portion of an outer wall formed from a flexible film, an opening communicating with the liquid storage chamber, a pressure plate that displaces in response to displacement of the flexible film, a first biasing member that biases the pressure plate in a direction to expand the liquid storage chamber, and the sealing member of the present invention, wherein the sealing member is positioned so that the distance between the elastic member of the sealing member and the opening changes in response to the displacement of the pressure plate, thereby changing the flow resistance to the liquid flowing through the opening, and the pressure of the liquid in the liquid storage chamber is adjusted.

[0009] The liquid ejection head of the present invention is characterized by having a plurality of recording element substrates each having an ejection port, a recording element that generates energy for ejecting liquid from the ejection port, and a pressure chamber having the recording element therein, a pair of common flow paths communicating with the plurality of recording element substrates, a plurality of individual flow paths that connect one common flow path of the pair of common flow paths to the other common flow path and communicate with the plurality of pressure chambers, and a pressure adjustment mechanism of the present invention connected to each of the upstream and downstream sides of the pair of common flow paths and set to different pressures. Also, the liquid ejection device of the present invention is characterized by having a liquid storage container that stores liquid, a pair of liquid ejection heads of the present invention, and a circulation mechanism that circulates the liquid in a circulation path including the pair of common flow paths. Effect of the Invention

[0010] According to the present invention, it is possible to obtain a sealing member for use, for example, in a pressure adjustment mechanism, which has a high-strength base member and is highly reliable, as well as a manufacturing method thereof, and a pressure adjustment mechanism, a liquid ejection head, and a liquid ejection device that use this sealing member. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a diagram illustrating a schematic configuration of a liquid ejection device. [Diagram 2] FIG. 2 is a diagram illustrating a first circulation mode. [Diagram 3] FIG. 11 is a diagram illustrating a second circulation mode. [Figure 4]5A and 5B are diagrams illustrating the amount of liquid flowing into the liquid ejection head. [Diagram 5] FIG. 2 is a perspective view illustrating a configuration of a liquid ejection head. [Figure 6] FIG. 2 is an exploded perspective view showing the liquid ejection head. [Figure 7] 3A and 3B are diagrams showing the configurations of the front and back surfaces of each flow path member. [Figure 8] FIG. 4 is a perspective view showing the connection relationship of each flow path. [Figure 9] FIG. 4 is a cross-sectional view showing a flow path forming member and a discharge module. [Figure 10] FIG. 2 is a diagram illustrating a discharge module. [Figure 11] FIG. 2 is a diagram showing a configuration of a recording element substrate. [Figure 12] FIG. 13 shows a third circulation mode. [Figure 13] FIG. 13 is a diagram showing a back pressure type pressure adjustment mechanism. [Figure 14] 14 is a cross-sectional view of the pressure adjustment mechanism shown in FIG. 13. [Figure 15] FIG. 1 is a perspective view showing a valve which is an example of a sealing member based on the present invention. [Figure 16] FIG. 4 is a schematic cross-sectional view showing the inclination of a pressing plate. [Figure 17] 4 is a cross-sectional view showing the movement of the pressure plate and the valve. FIG. [Figure 18] 4 is a cross-sectional view showing the vicinity of a valve in the pressure adjustment mechanism. FIG. [Figure 19] FIG. 4 is a cross-sectional view illustrating the molding of a valve. [Figure 20] FIG. [Figure 21] 11A and 11B are cross-sectional views for explaining molding of a valve when no resin introduction path is provided. [Figure 22] FIG. 13 is a diagram showing a pressure reducing type pressure adjustment mechanism. [Figure 23] 23 is a diagram showing a valve used in the pressure adjustment mechanism shown in FIG. 22. [Figure 24] FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] An embodiment of the present invention will be described with reference to the drawings. The sealing member according to the present invention is a base member made of a material having high rigidity and an elastic member made of a flexible material bonded to it, and is used to create an airtight state or change flow resistance as necessary in a valve or the like. The elastic member has a function of, for example, abutting against a surface around an opening through which a liquid flows as necessary to maintain an airtight state. Such a sealing member is used, for example, as a valve in a pressure adjustment mechanism having a back pressure valve mechanism or a pressure reducing valve mechanism, is used to regulate the flow direction of a fluid in a check valve, or is used as a gasket to prevent leakage of a fluid. Furthermore, it is also used to cover a specific area airtight as necessary so that the area is not exposed to the atmosphere. The following mainly describes the case where the sealing member according to the present invention is used as a valve in a pressure adjustment mechanism. First, in order to understand the present invention, a liquid ejection device, which is an example of an apparatus in which a pressure adjustment mechanism is used, will be described. Of course, the apparatus to which the pressure adjustment mechanism according to the present invention can be applied is not limited to a liquid ejection device.

[0013] (Liquid discharge device) A liquid ejection device ejects liquid from an ejection port. One example of a liquid ejection device is an inkjet recording device that ejects recording liquid such as ink from an ejection port onto a recording medium such as paper to record an image on the recording medium. FIG. 1 shows a schematic configuration of a liquid ejection device 2000 configured as an inkjet recording device that ejects liquid onto a recording medium 2 to perform recording on the recording medium 2. The liquid ejection device 2000 includes a conveying section 1 that conveys the recording medium 2, and four liquid ejection heads 3 arranged in parallel to each other and substantially perpendicular to the conveying direction of the recording medium 2, and ejects liquid from the liquid ejection heads 3 while conveying the recording medium 2. The four liquid ejection heads 3 eject recording liquid, i.e., ink, of each color of cyan (C), magenta (M), yellow (Y), and black (K). Hereinafter, the colors of cyan (C), magenta (M), yellow (Y), and black (K) are also collectively referred to as CMYK. By including the four color liquid ejection heads 3, the liquid ejection device 2000 can perform full-color recording on the recording medium 2. As described later, a supply system in the liquid ejection device 2000, i.e., a buffer tank 1003 (see FIGS. 2 and 3) which is a liquid storage container for storing liquid, and a main tank 1006 (see FIGS. 2 and 3) are fluidly connected to each liquid ejection head 3. In addition, an electric control unit which transmits power and ejection control signals to each liquid ejection head 3 is electrically connected to each liquid ejection head 3.

[0014] The liquid ejection device 2000 shown here is configured to circulate liquid such as recording liquid between a buffer tank 1003 and a liquid ejection head 3. The liquid circulation modes in the liquid ejection device 2000 include a first circulation mode in which two circulation pumps, one for high pressure and one for low pressure, operate downstream of the liquid ejection head 3 to circulate the liquid, and a second circulation mode in which similar two circulation pumps operate upstream of the liquid ejection head 3. The first and second circulation modes will be described below.

[0015] (first circulation form) FIG. 2 is a schematic diagram showing a first circulation mode applied to the liquid ejection device 2000. In the first circulation mode, the liquid ejection head 3 is fluidly connected to a first circulation pump 1001 on the high pressure side, a first circulation pump 1002 on the low pressure side, a buffer tank 1003, and the like. In FIG. 2, only a path through which one of the recording liquids of each color of CMYK flows is shown for the sake of simplicity of explanation, but in reality, the liquid ejection device 2000 is provided with the path shown here for each liquid ejection head 3. The buffer tank 1003 as a sub-tank is connected to the main tank 1006 and has an air communication port (not shown) that communicates the inside of the tank with the outside, and is capable of discharging air bubbles in the recording liquid to the outside. The buffer tank 1003 is also connected to a refill pump 1005. When the recording liquid is consumed by ejecting (discharging) the recording liquid from the ejection port of the liquid ejection head 3, such as for recording by ejecting the recording liquid or for suction recovery, the refill pump 1005 transfers the consumed amount of recording liquid from the main tank 1006 to the buffer tank 1003.

[0016] The liquid ejection head 3 is provided with a liquid ejection unit 300 in which the ejection ports are actually provided, and a liquid supply unit 220 including a pressure control unit 230 that adjusts the pressure of the liquid circulating through the liquid ejection unit 300. The liquid ejection unit 300 includes a plurality of recording element substrates 10, and a common supply flow path 211 and a common recovery flow path 212 that form part of a liquid circulation path. The common supply flow path 211 and the common recovery flow path 212 form a pair of common flow paths. The recording liquid supplied to the buffer tank 1003 is supplied to the liquid supply unit 220 via the liquid connection part 111 of the liquid ejection head 3 by a second circulation pump 1004, as described later.

[0017] The two first circulation pumps 1001 and 1002 have a role of drawing liquid from the liquid connection part 111 of the liquid discharge head 3 and flowing it to the buffer tank 1003. It is preferable to use a volumetric pump having a quantitative liquid delivery capacity as the first circulation pumps 1001 and 1002. Specifically, a tube pump, a gear pump, a diaphragm pump, a syringe pump, etc. can be mentioned, but for example, a pump in a form in which a general constant flow valve or a relief valve is arranged at the pump outlet to ensure a constant flow rate can also be used. In addition, a form in which a flow sensor is provided in the circulation path and the rotation speed of the pump is controlled from a control circuit in the main body based on the sensor output value to ensure a constant flow rate can also be preferably used. When the liquid discharge head 3 is driven, the first circulation pump 1001 on the high pressure side and the first circulation pump 1002 on the low pressure side cause the recording liquid to flow at a certain constant flow rate in the common supply flow path 211 and the common recovery flow path 212 of the liquid discharge unit 300, respectively. By flowing the recording liquid in this way, the temperature of the liquid discharge head 3 during recording is maintained at an optimal temperature. It is preferable to set the flow rate of the recording liquid to a level at which the temperature difference between each recording element substrate 10 in the liquid ejection head 3 does not affect the recording quality on the recording medium 2. However, if an excessively large flow rate is set, the negative pressure difference between each recording element substrate 10 becomes too large due to the influence of pressure loss in the flow path in the liquid ejection unit 300, resulting in uneven density in the recorded image. For this reason, it is preferable to set the flow rate while taking into consideration the temperature difference and negative pressure difference between each recording element substrate 10.

[0018] The pressure control unit 230 is provided in a path between the second circulation pump 1004 and the liquid discharge unit 300, and the recording liquid is supplied from the second circulation pump 1004 through a filter 221. The pressure control unit 230 operates to maintain the pressure downstream of the pressure control unit 230 (i.e., the liquid discharge unit 3 side) at a preset constant pressure even if the flow rate of the recording liquid in the circulation system fluctuates. The change in the flow rate of the recording liquid in the circulation system occurs, for example, when the discharge amount per unit area changes when the recording liquid is discharged onto the recording medium 2 to perform recording. The pressure control unit 230 includes two pressure adjustment mechanisms 230H, 230L, each of which is set with a different control pressure. In the figure, the letter "H" indicates the high-pressure side pressure adjustment mechanism 230H, and the letter "L" indicates the low-pressure side pressure adjustment mechanism 230L. These two pressure adjustment mechanisms 230H, 230L may be any mechanism as long as they can control the pressure downstream of the pressure control unit 230 within a certain range of fluctuation centered on the desired control pressure. As an example, a mechanism similar to a so-called pressure reducing valve or pressure reducing regulator can be used. By pressurizing the upstream side of the pressure control unit 230 by the second circulation pump 1004 via the liquid supply unit 220 as in the first circulation form, the influence of the head pressure of the buffer tank 1003 on the liquid ejection head 3 can be suppressed. As a result, the degree of freedom of layout of the buffer tank 1003 in the liquid ejection device 2000 can be increased. As the second circulation pump 1004, it is sufficient that it has a head pressure of a certain pressure or more within the range of the circulation flow rate of the recording liquid used when driving the liquid ejection head 3, and a turbo pump, a positive displacement pump, or the like can be used. Specifically, a diaphragm pump, or the like can be used. In place of the second circulation pump 1004, for example, a head tank arranged with a certain head difference with respect to the pressure control unit 230 can be provided.

[0019] Of the two pressure adjustment mechanisms in the pressure control unit 230, the pressure adjustment mechanism 230H, which is set to a relatively high pressure, is connected to the inlet of the common supply flow path 211 in the liquid ejection unit 300 via the liquid connection part 100 through the liquid supply unit 220. Similarly, the pressure adjustment mechanism 230L, which is set to a relatively low pressure, is connected to the inlet of the common recovery flow path 212 in the liquid ejection unit 300 via the liquid connection part 100 through the liquid supply unit 220. The outlets of the common supply flow path 211 and the common recovery flow path 212 are connected to the first circulation pumps 1001 and 1002, respectively, via the liquid connection part 100, the liquid supply unit 220, and the liquid connection part 111. As a result, a high-pressure side circulation path is formed that runs from the buffer tank 1003 through the second circulation pump 1004, the high-pressure side pressure adjustment mechanism 230H, the common supply flow path 211, the high-pressure side first circulation pump 1001, and back to the buffer tank 1003. Also, a low-pressure side circulation path is formed that runs from the buffer tank 1003 through the second circulation pump 1004, the low-pressure side pressure adjustment mechanism 230L, the common recovery flow path 211, the low-pressure side first circulation pump 1002, and back to the buffer tank 1003. The first circulation pumps 1001 and 1002, the second circulation pump 1004, and the pressure control unit 230 correspond to a circulation mechanism for circulating the liquid in the first circulation mode.

[0020] In addition to the multiple recording element substrates 10, the common supply flow path 211, and the common recovery flow path 212, the liquid ejection unit 300 is provided with individual supply flow paths 213 and individual recovery flow paths 214 that are connected to each recording element substrate 10. The individual supply flow paths 213 and individual recovery flow paths 214 that are provided for each recording element substrate 10 are collectively referred to as individual flow paths 215. The individual flow paths 215 are provided so as to branch off from the common supply flow path 211, which is at a relatively high pressure, and merge with the common recovery flow path 212, which is at a relatively low pressure, and are connected to these. Therefore, a flow (white arrow in FIG. 2) occurs in which a part of the liquid, such as the recording liquid, passes through the internal flow path of the recording element substrate 10 from the common supply flow path 211 toward the common recovery flow path 212. This is because a pressure difference occurs between the common supply flow path 211 and the common recovery flow path 212, since the high-pressure pressure adjustment mechanism 230H is connected to the common supply flow path 211, and the low-pressure pressure adjustment mechanism 230L is connected to the common recovery flow path 212.

[0021] In the liquid ejection unit 300, a flow occurs in which liquid flows through the common supply flow path 211 and the common recovery flow path 212, while a part of the liquid passes through each recording element substrate 10. Therefore, heat generated in each recording element substrate 10 can be discharged to the outside of the recording element substrate 10 by the flow through the common supply flow path 211 and the common recovery flow path 212. In addition, when recording is performed by the liquid ejection head 3, a flow of recording liquid can be generated even in ejection ports and pressure chambers that are not performing recording, so that an increase in the viscosity of the recording liquid due to evaporation of the solvent component of the recording liquid at that site can be suppressed. In addition, the thickened recording liquid and foreign matter in the recording liquid can be discharged to the common recovery flow path 212. Therefore, by using the above-mentioned liquid ejection head 3, high-speed and high-quality recording can be performed.

[0022] (Second circulation form) 3 is a schematic diagram showing a second circulation mode in the liquid ejection device 2000. The main difference from the first circulation mode described above is that the two pressure adjustment mechanisms 230H, 230L constituting the pressure control unit 230 are mechanisms for controlling the pressure upstream of the pressure control unit 230 to fluctuate within a certain range centered on a desired set pressure. Accordingly, the second circulation pump 1004 acts as a negative pressure source for reducing the pressure downstream of the pressure control unit 230. The first circulation pumps 1001, 1002 on the high pressure side and low pressure side are disposed upstream of the liquid ejection head 3, and the pressure control unit 230 is disposed downstream of the liquid ejection head 3.

[0023] In the second circulation mode, the recording liquid in the main tank 1006 is supplied to the buffer tank 1003 by the refill pump 1005, and then branches into high-pressure and low-pressure flow paths. In the high-pressure flow path, the recording liquid is supplied to the common supply flow path 211 through the filter 221 by the first circulation pump 1001. The recording liquid discharged from the common supply flow path 211 passes through the pressure adjustment mechanism 230H set to the high pressure side, merges with the low-pressure side flow path, and circulates to the buffer tank 1003 through the second circulation pump 1004. On the other hand, in the low-pressure side flow path, the recording liquid is supplied to the common recovery flow path 212 through the filter 221 by the first circulation pump 1002. The recording liquid discharged from the common recovery flow path 212 passes through the pressure adjustment mechanism 230L set to the low pressure side, merges with the high-pressure side flow path, and circulates to the buffer tank 1003 through the second circulation pump 1004. Also in this second circulation mode, the two pressure adjustment mechanisms 230H, 230L make the pressure in the common supply flow path 211 relatively higher than the pressure in the common recovery flow path 212. As a result, a flow of recording liquid is generated from the common supply flow path 211 through the individual flow paths 215 to the common recovery flow path 212. The first circulation pumps 1001, 1002, the second circulation pump 1004, and the pressure control unit 230 correspond to a circulation mechanism for circulating the liquid.

[0024] The pressure control unit 230 in the second circulation form maintains the pressure fluctuation on the upstream side of the pressure control unit 230 (i.e., the liquid ejection unit 3 side) within a certain range centered on a preset pressure even if the flow rate of the circulating recording liquid fluctuates. The pressure adjustment mechanisms 230H, 230L provided in the pressure control unit 230 may be any mechanisms capable of maintaining the pressure in this way, and as an example, a mechanism called a back pressure valve or back pressure regulator may be adopted. In the circulation flow path in the second circulation form, the second circulation pump 1004 reduces the pressure on the downstream side of the pressure control unit 230 via the liquid supply unit 220. In this way, the influence of the head pressure of the buffer tank 1003 on the liquid ejection head 3 can be suppressed, so that the layout of the buffer tank 1003 in the liquid ejection device 2000 can be selected from a wider range. Instead of the second circulation pump 1004, for example, a head tank arranged with a predetermined head difference with respect to the pressure control unit 230 may be used.

[0025] In the second circulation mode, the same flow state of the recording liquid as in the first circulation mode is obtained inside the liquid discharge unit 300, but the second circulation mode has two advantages different from the first circulation mode. The first advantage is that dust or foreign matter mixed in the pressure control unit 230 is prevented from flowing into the liquid discharge head 3. The pressure adjustment mechanisms 230H and 230L constituting the pressure control unit 230 are equipped with valves, and dust or foreign matter may be mixed into the pressure control unit 230 when the valves are opened and closed. In the second circulation mode, the pressure control unit 230 is disposed downstream of the liquid discharge head 3, and the filter 221 is disposed upstream of the liquid discharge head 3. Therefore, when the recording liquid is circulated through the circulation path by the operation of the first circulation pumps 1001 and 1002 and the second circulation pump 1004, foreign matter mixed in the pressure control unit 230 is removed from the recording liquid, and the foreign matter can be prevented from flowing into the liquid discharge head 3.

[0026] The second advantage is that in the second circulation mode, the maximum flow rate required to supply liquid from the buffer tank 1003 to the liquid ejection head 3 is smaller than that in the first circulation mode. The reason is as follows. The total flow rate in the common supply flow path 211, the common recovery flow path 212, and the individual flow paths 215 during circulation during standby for recording is defined as flow rate A. The value of flow rate A is defined as the minimum flow rate required to keep the temperature difference in the liquid ejection unit 300 within a desired range when adjusting the temperature of the liquid ejection head 3 during standby for recording. In addition, the ejection flow rate when ejecting recording liquid from all the ejection ports of the liquid ejection unit 300 (during full ejection) is defined as flow rate F. The flow rate F is defined as the product of the amount of recording liquid ejected per ejection port, the number of ejections per unit time (i.e., the ejection frequency), and the number of ejection ports. FIG. 4 is a schematic diagram showing the difference in the amount of recording liquid flowing into the liquid ejection head 3 between the first circulation mode and the second circulation mode. Fig. 4(a) shows the state when the ink is on standby for recording in the first circulation mode, and Fig. 4(b) shows the state when the ink is fully discharged in the first circulation mode. Fig. 4(c) to Fig. 4(f) show the inflow rate of the ink in the second circulation flow path, and Fig. 4(c) and Fig. 4(d) show the case when the flow rate F is less than the flow rate A, and Fig. 4(e) and Fig. 4(f) show the case when the flow rate F is greater than the flow rate A, showing the flow rates when the ink is on standby for recording and when the ink is fully discharged, respectively.

[0027] In the case of the first circulation configuration in which the first circulation pumps 1001, 1002 having a quantitative liquid delivery capacity are disposed downstream of the liquid ejection head 3 (FIGS. 4(a) and 4(b)), the total set flow rate of the first circulation pumps 1001, 1002 is flow rate A. This flow rate A enables temperature control inside the liquid ejection unit 300 during standby. When full ejection is performed by the liquid ejection head 3, the total set flow rate of the first circulation pumps 1001, 1002 remains at flow rate A, but the negative pressure generated in the liquid ejection unit 300 by ejection affects the flow rate of the recording liquid. Therefore, the maximum flow rate supplied to the liquid ejection head 3 is the total set flow rate A plus the consumption amount (flow rate F) due to full ejection. Therefore, the maximum value of the amount of supply to the liquid ejection head 3 during full ejection is flow rate A+flow rate F, since flow rate F is added to flow rate A (FIG. 4(b)).

[0028] Here, in the first circulation mode shown in FIG. 2, it is considered that some of the recording element substrates 10 are in a recording standby state, and the recording liquid is discharged from all the discharge ports of the remaining recording element substrates 10. In FIG. 2, the recording element substrates 10 shown in a shaded state indicate the recording element substrates 10 in a full discharge state, and the recording element substrates 10 without a shaded state indicate the recording element substrates 10 in a recording standby state. At this time, the recording element substrates 10 in a full discharge state are supplied with recording liquid from the common supply flow path 211 as shown by the white arrow in the figure, and in addition, a certain amount of recording liquid is also supplied from the common recovery flow path 212 as shown by the black arrow in the figure. On the other hand, the recording element substrates 10 in a recording standby state are continuously supplied with recording liquid from the common supply flow path 211 as shown by the white arrow in the figure. Although the amount of recording liquid flowing into the liquid discharge unit 300 increases, and thus the pressure difference between the common supply flow path 211 and the common recovery flow path 212, which are the common flow paths, fluctuates to some extent, the effect of which can be ignored if the cross-sectional area of ​​the common flow path can be sufficiently secured.

[0029] In this way, in the first circulation mode, even if some of the recording element substrates 10 are in a standby state while the other recording element substrates 10 are in a full discharge state, the recording liquid is also supplied to the recording element substrates 10 in a standby state. With this configuration, the amount of recording liquid supplied to the liquid discharge head 3 can be suitably controlled. That is, the pressure difference in the common flow path is controlled so that the flow rate of the recording liquid passing through the individual flow paths 215 in the recording element substrates 10 in a standby state is smaller than the discharge flow rate of the recording liquid discharged from all the discharge ports 13 in the recording element substrates 10. By controlling the pressure difference between the common supply flow path 211 and the common recovery flow path 212 as described above, the amount of recording liquid circulated to the recording element substrates 10 in a standby state can be suppressed, regardless of the fluctuation in the discharge flow rate from the discharge ports of the liquid discharge heads 3. If the amount of recording liquid circulated to the recording element substrates 10 in a standby state can be suppressed, the dissipation of heat from the liquid discharge heads 3 can be suppressed, and the cooling mechanism for cooling the recording liquid in the circulation flow path can be simplified.

[0030] In the case of the second circulation mode (FIGS. 4(c) to 4(f)), in which the first circulation pumps 1001 and 1002 are disposed upstream of the liquid ejection head 3, the amount of recording liquid required to be supplied to the liquid ejection head 3 during recording standby is the flow rate A, as in the first circulation mode. Therefore, in the second circulation mode, when the flow rate A is greater than the flow rate F (FIGS. 4(c) and 4(d)), the amount of recording liquid supplied to the liquid ejection head 3 is sufficient even during full ejection. In that case, the discharge flow rate from the liquid ejection head 3 is the flow rate A minus the flow rate F (FIG. 4(d)). However, when the flow rate F is greater than the flow rate A (FIGS. 4(e) and 4(f)), if the supply flow rate to the liquid ejection head 3 is the flow rate A during full ejection, the flow rate of the recording liquid is insufficient. Therefore, in the second circulation mode, when the flow rate F is greater than the flow rate A, the amount of recording liquid supplied to the liquid ejection head 3 must be the flow rate F. Furthermore, if full ejection is performed in this state, the flow rate F is consumed in the liquid ejection head 3, so the discharge flow rate from the liquid ejection head 3 becomes almost zero (FIG. 4(f)). When the flow rate F is greater than the flow rate A and ejection is performed but not fully ejected, the recording liquid is discharged from the liquid ejection head 3 at a flow rate obtained by subtracting the amount consumed in ejection from the flow rate F.

[0031] In the second circulation mode, the total value of the set flow rates of the first circulation pumps 1001 and 1002, i.e., the maximum value of the required supply flow rate, is the larger value of the flow rate A or the flow rate F. Therefore, as long as the liquid ejection unit 300 having the same configuration is used, the maximum value of the required supply flow rate in the second circulation mode (the larger value of the flow rate A or the flow rate F) is smaller than the maximum value of the required supply flow rate in the first circulation mode (flow rate A+flow rate F). Note that even in the second circulation mode, when some of the recording element substrates 10 are in a recording standby state and the remaining recording element substrates 10 are in a full ejection state, the recording liquid is also supplied to the recording element substrates 10 in a recording standby state. Also in the second circulation mode, by controlling the differential pressure between the common supply flow path 211 and the common recovery flow path 212, the flow rate of the recording liquid circulated to the recording element substrates 10 in a recording standby state can be suppressed regardless of the fluctuation in the ejection flow rate of the recording liquid from the ejection port of the liquid ejection head 3. In the case of the second circulation form, the degree of freedom of the applicable circulation pump is increased, for example, a low-cost circulation pump with a simple configuration can be used, and the load on the cooler (not shown) installed in the main body side path can be reduced, thereby reducing the cost of the recording device main body. This advantage becomes greater as the page-wide type head has a relatively large value of A or F, and is more beneficial for page-wide type heads that are longer in the longitudinal direction.

[0032] However, on the other hand, the first circulation mode has an advantage over the second circulation mode in some respects. In the second circulation mode, the flow rate flowing through the liquid ejection unit 300 during recording standby is at its maximum, so the greater the image to be recorded is an image with a smaller ejection amount per unit area (also called a low-duty image), the greater the negative pressure applied to each ejection port. When recording a low-duty image in which recording unevenness is easily noticeable, a high negative pressure is applied to the ejection port, so that many so-called satellite droplets are generated that are ejected in association with the main droplets of the recording liquid, which may result in a decrease in recording quality. On the other hand, in the case of the first circulation mode, a high negative pressure is applied to the ejection port when an image with a large ejection amount per unit area (also called a high-duty image) is formed, so that even if satellite droplets are generated, they are difficult to see, and there is an advantage that the impact on the image is small. These two circulation modes can be preferably selected in light of the specifications (ejection flow rate F, minimum circulation flow rate A, and flow path resistance in the liquid ejection head 3) of the liquid ejection head 3 and the recording device main body.

[0033] (Structure of liquid ejection head) Next, the structure of the liquid ejection head 3 will be described with reference to FIG. 5. FIG. 5(a) is a perspective view of the liquid ejection head 3 as viewed from the side where the ejection ports are formed, and FIG. 5(b) is a perspective view as viewed from the opposite direction to FIG. 5(a). The liquid ejection head 3 is a line-shaped liquid ejection head having, for example, 16 recording element substrates 10 arranged in a straight line (arranged in-line) in the longitudinal direction, and is an inkjet type that performs recording with a single color recording liquid. The liquid ejection head 3 is provided with a signal input terminal 91 and a power supply terminal 92 in addition to the above-mentioned liquid connection portion 111 provided for circulating the recording liquid between the liquid ejection device 2000. The signal input terminal 91 and the power supply terminal 92 are arranged on both sides of the liquid ejection head 3. This is to reduce voltage drops and signal transmission delays that occur in the wiring portion provided on the recording element substrate 10. In the circulation form shown in FIG. 2 and FIG. 3, one liquid supply unit 220 is provided in the liquid ejection head 3, and one pressure control unit 230 is attached to the liquid supply unit 2220. And, two pressure adjustment mechanisms 230H, 230L are provided in the pressure control unit 230. However, the liquid ejection head 3 described below includes two liquid supply units 2220, and a pressure control unit 2230 including one pressure adjustment mechanism is provided for each liquid supply unit 220. The two liquid supply units 2220 are provided at both ends of the liquid ejection head 3 in the longitudinal direction.

[0034] 6 is a perspective exploded view of the liquid ejection head 3, and each part or unit constituting the liquid ejection head 3 is divided and displayed according to its function. In the liquid ejection head 3, a flow path component 210 is constituted by a first flow path member 50 and a second flow path member 60, and a liquid ejection unit 300 is constituted by combining a plurality of ejection modules 200 with the flow path component member 210. A cover member 130 is attached to the surface of the liquid ejection unit 300 on the recording medium side. The cover member 130 is a member having a frame-shaped surface in which a long opening 131 is provided, and the opening 131 is formed to expose the recording element substrate 10 and its sealant included in the ejection module 200. The frame portion around the opening 131 functions as an abutment surface of a cap member that caps the surface of the liquid ejection head 3 on which the ejection ports are formed during standby for recording. For this reason, it is preferable to apply an adhesive, sealant, filler, etc. around the periphery of the opening 131 to fill in any irregularities or gaps on the ejection port forming surface of the liquid ejection unit 300 so that a closed space is formed when capping.

[0035] Furthermore, the liquid ejection head 3 includes two liquid ejection unit support parts 81 and two electric wiring boards 90. In this liquid ejection head 3, the rigidity of the head is ensured mainly by the second flow path member 60. The liquid ejection unit support parts 81 are connected to both ends of the second flow path member 60, and are mechanically coupled to a carriage of the liquid ejection device 2000 to position the liquid ejection head 3. Each liquid supply unit 2220 including a pressure control unit 2230 is coupled to the liquid ejection unit support part 81 with a liquid connection part 100 made of joint rubber sandwiched therebetween, and the electric wiring board 90 is also coupled to the liquid ejection unit support part 81. A filter 221 (see FIG. 12) is built into each of the two liquid supply units 2220.

[0036] The two pressure control units 2230 are set to control different, relatively high and low pressures. That is, as shown in FIG. 12 described later, the pressure adjustment mechanism provided in one pressure control unit 2230 is for the high pressure side, and the pressure adjustment mechanism provided in the other pressure control unit 2230 is for the low pressure side. Details of the pressure control unit 2230 will be described later. When the high pressure side and low pressure side pressure control units 2230 are installed at both ends of the liquid ejection head 3 in this way, the liquid flows in the common supply flow path 211 and the common recovery flow path 212 extending in the longitudinal direction of the liquid ejection head 3 face each other and become countercurrents. In this configuration, heat exchange is promoted between the common supply flow path 211 and the common recovery flow path 212, and the temperature difference in the two common flow paths is reduced. This reduces the temperature difference between the recording element substrates 10 provided along the common flow path, and has the advantage of making it difficult for uneven recording due to the temperature difference to occur.

[0037] Next, the flow path component 210 of the liquid ejection unit 300 will be described in detail. As shown in FIG. 6, the flow path component 210 is a laminate of a first flow path component 50 and a second flow path component 60, and distributes the liquid supplied from the liquid supply unit 2220 to each ejection module 200. The flow path component component 210 also functions as a flow path component for returning the recording liquid circulating from the ejection module 200 to the liquid supply unit 2220. The second flow path component 60 is a component in which a common supply flow path 211 and a common recovery flow path 212 are formed, and has a function of mainly providing the rigidity of the liquid ejection head 3. For this reason, the material of the second flow path component 60 is preferably one having sufficient corrosion resistance against liquid and high mechanical strength, and specifically, stainless steel, titanium, alumina, etc. can be preferably used.

[0038] Next, the first flow path member 50 and the second flow path member 60 will be described in detail with reference to FIG. 7. FIG. 7(a) shows the surface of the first flow path member 50 on which the discharge module 200 is attached, and FIG. 7(b) shows the back surface thereof, which is the surface on which the second flow path member 60 is abutted. The first flow path member 50 is formed by arranging a plurality of members corresponding to each discharge module 200 adjacent to each other. By adopting such a divided structure and arranging a plurality of such modules, it becomes possible to correspond to the length required for the liquid discharge head 3. This configuration is particularly suitable for use in a relatively long liquid discharge head having a length corresponding to, for example, JIS (Japanese Industrial Standards) B2 size or larger. As shown in FIG. 7(a), the communication port 51 of the first flow path member 50 is fluidly communicated with the discharge module 200, and as shown in FIG. 7(b), the individual communication port 53 of the first flow path member 50 is fluidly communicated with the communication port 61 of the second flow path member 60. 7(c) shows the surface of the second flow path member 60 that comes into contact with the first flow path member 50, FIG. 7(d) shows a cross section of the center of the second flow path member 60 in the thickness direction, and FIG. 7(e) shows the surface of the second flow path member 60 that comes into contact with the liquid supply unit 2220. The communication port 72 shown in FIG. 7(e) communicates with the pressure control unit 2230 via the liquid connection part 100 shown in FIG. 6, and the recording liquid is supplied to the second flow path member 60 from one communication port 72 and discharged from the other communication port 72. One of the common flow path grooves 71 of the second flow path member 60 is the common supply flow path 211 shown in FIG. 8, and the other is the common recovery flow path 212, and each of them supplies liquid from one end side to the other end side along the longitudinal direction of the liquid ejection head 3. As described above, the flow directions of the liquid in the common supply flow path 211 and the common recovery flow path 212 are opposite to each other along the longitudinal direction of the liquid ejection head 3.

[0039] 8 shows a perspective view of the connection relationship of each flow path between the recording element substrate 10 and the flow path forming member 210. As shown in FIG. 8, a pair of a common supply flow path 211 and a common recovery flow path 212 extending in the longitudinal direction of the liquid ejection head 3 is provided in the flow path forming member 210. The communication port 61 of the second flow path member 60 is aligned and connected to the individual communication port 53 of each first flow path member 50, and a liquid supply path is formed that communicates from the communication port 72 of the second flow path member 60 to the communication port 51 of the first flow path member 50 via the common supply flow path 211. Similarly, a liquid supply path is also formed that communicates from the communication port 72 of the second flow path member 60 to the communication port 51 of the first flow path member 50 via the common recovery flow path 212.

[0040] FIG. 9 is a diagram showing a cross section taken along line IX-IX in FIG. 8. As shown in this figure, the common supply flow path 211 is connected to the discharge module 200 via the communication port 61, the individual communication port 53, and the communication port 51. Although not shown in FIG. 9, it is clear from FIG. 8 that the common recovery flow path 212 is connected to the discharge module 200 via a similar route in another cross section. In each discharge module 200 and the recording element substrate 10, a flow path is formed that communicates with the pressure chamber in which each discharge port 13 (see FIG. 11) is formed. A part or all of the supplied liquid can be returned by this flow path through the pressure chamber corresponding to the discharge port 13 that is not discharging. The common supply flow path 211 is connected to the high-pressure side pressure control unit 2230, and the common recovery flow path 212 is connected to the low-pressure side pressure control unit 2230, respectively, via the liquid supply unit 2220. Therefore, due to a pressure difference generated by these pressure control units 2230, a flow is generated from the common supply flow path 211 through the pressure chamber of the recording element substrate 10 toward the common recovery flow path 212.

[0041] (Discharge module) FIG. 10(a) is a perspective view showing one discharge module 200, and FIG. 10(b) is an exploded view thereof. In the discharge module 200, the recording element substrate 10 is disposed on a support member 30. A plurality of terminals 16 (see FIG. 11) are disposed on both sides of the recording element substrate 10 along the discharge port array direction, i.e., on each of the long sides of the recording element substrate 10. Accordingly, two flexible wiring substrates 40 electrically connected to the recording element substrate 10 are also disposed for one recording element substrate 10. This is because the number of discharge port arrays provided on one recording element substrate 10 is, for example, 20, and the maximum distance from the terminals 16 to the recording elements is shortened to reduce voltage drop and signal delay occurring in the wiring portion in the recording element substrate 10. The support member 30 is a support body that supports the recording element substrate 10, and is also a flow path connecting member that fluidly connects the recording element substrate 10 and the flow path forming member 210. The liquid communication port 31 of the support member 30 is open so as to straddle all of the ejection port rows provided on the recording element substrate 10.

[0042] (Structure of the recording element substrate) The configuration of the recording element substrate 10 will be described with reference to FIG. 11. FIG. 11(a) is a schematic diagram of the surface of the recording element substrate 10 on which the ejection ports 13 are arranged, FIG. 11(b) is a diagram showing a portion in which the liquid supply path 18 and the liquid recovery path 19 are formed, and FIG. 11(c) is a plan view of the back side of FIG. 11(a). Here, FIG. 11(b) shows a state in which the cover member 20 provided on the back side of the recording element substrate 10 in FIG. 11(c) is removed. An energy generating element is provided below the ejection ports 13 of the recording element substrate 10, and when energy is applied to the recording liquid by the energy generating element, the recording liquid is ejected from the ejection ports 13 to perform recording. As shown in FIG. 11(b), the liquid supply path 18 and the liquid recovery path 19 are alternately provided on the back side of the recording element substrate 10 along the ejection port array direction. The terminals 16 are arranged on both sides of the recording element substrate 10 along the ejection port array direction. A set of liquid supply path 18 and liquid recovery path 19 is provided for each row of ejection ports, and the cover member 20 is provided with an opening 21 that communicates with a liquid communication port 31 of the support member 30 .

[0043] (Third circulation form) Next, the third circulation mode, which is the circulation mode in the liquid ejection device 2000 described with reference to Figs. 5 to 11, will be described with reference to Fig. 12. In the liquid ejection head 3 of the liquid ejection device 2000 described with reference to Figs. 5 to 11, the flow direction of the recording liquid in the common supply flow path 211 and the flow direction of the recording liquid in the common recovery flow path 212 face each other. The third circulation mode shown in Fig. 12 is based on the second circulation mode shown in Fig. 3, and the arrangement of the pressure control unit 2230 and the like are slightly changed according to the difference in the flow direction of the recording liquid, and the basic operation is the same as that of the second circulation mode. The liquid ejection head 3 is provided with a high pressure side (H) and a low pressure side (L) pressure control unit 2230 at both ends in the longitudinal direction of the liquid ejection head 3. Each of these pressure control units 2230 is provided with a pressure adjustment mechanism. The recording liquid passes through the common recovery flow path 211 or the common supply flow path 212 , flows into each pressure control unit 230 , and is guided to the second circulation pump 1004 via the liquid connection part 111 .

[0044] (Back pressure type pressure adjustment mechanism) Next, a pressure adjustment mechanism according to an embodiment of the present invention will be described. Figures 13 and 14 show a pressure adjustment mechanism according to an embodiment. This pressure adjustment mechanism is a back pressure type, and is preferably used as a pressure adjustment mechanism provided in the pressure control unit 2230 in the liquid ejection device 2000 described with reference to Figures 4 to 11. In particular, this pressure adjustment mechanism is suitable for the second and third circulation modes described above. Figures 13(a) and 13(b) are respectively a perspective view and a front view of the appearance of the pressure adjustment mechanism, Figure 14(a) is a cross-sectional view of the pressure adjustment mechanism taken along line AA in Figure 13(a), and Figure 14(b) is a cross-sectional view explaining the operation of the pressure adjustment mechanism. In Figure 13, the pressure control unit 2230 including the pressure adjustment mechanism is depicted in a state where it is attached to the liquid supply unit 2220 of the liquid ejection device 2000.

[0045] The pressure adjustment mechanism has a housing in a flat, substantially rectangular parallelepiped shape, and a flexible film 405 is arranged so as to cover one open surface of the housing. The remaining five surfaces of the housing and the flexible film 405 form a first liquid storage chamber 401 that can store a liquid such as a recording liquid therein and has a variable volume. The first liquid storage chamber 401 corresponds to a first pressure chamber provided in a back pressure type pressure adjustment mechanism, and at least a part of its outer wall is formed by the flexible film 405. The pressing plate 404 is a member that functions as a pressure receiving plate in the back pressure type pressure adjustment mechanism, is fixed to the inner surface side (the side of the first liquid storage chamber 401) of the flexible film 405, and presses the flexible film 405 in a direction to expand the first liquid storage chamber 401. A negative pressure spring 411 is interposed between the pressing plate 404 and the housing as a first biasing member, and the negative pressure spring 411 biases the pressing plate 404 in a direction that expands the first liquid storage chamber 401 outward. In other words, the negative pressure spring 411 biases the pressing plate 404, and the biased pressing plate 404 presses the flexible film 405 in a direction that expands the volume of the first liquid storage chamber 401.

[0046] 14(a), arrow Z indicates the vertically upward direction. An inlet 414 for allowing liquid to flow into the first liquid storage chamber 401 is formed vertically below the first liquid storage chamber 401. When this pressure adjustment mechanism is used in the liquid ejection device 2000, the inlet 414 communicates with the common recovery channel 211 or the common supply channel 212. Note that the vertical direction in this embodiment is the vertical direction when the pressure adjustment mechanism is in use (when a pressure control unit 2230 having a pressure adjustment mechanism is attached to the liquid ejection device 2000 to control the pressure of the liquid).

[0047] A valve chamber 402 is disposed vertically above the first liquid storage chamber 401, and communicates with the first liquid storage chamber 401 to form a part of the first liquid storage chamber 401. An outlet 410 is formed as an opening in the valve chamber 402 for discharging liquid from the inside of the first liquid storage chamber 401 to the outside. A second liquid storage chamber 403 different from the first liquid storage chamber 401 is provided beyond the outlet 410, and the outlet 410 is formed between the first liquid storage chamber 401 and the second liquid storage chamber 403. When this pressure adjustment mechanism is provided in the liquid ejection device 2000, the second liquid storage chamber 403 is connected to the second circulation pump 1004 via a liquid connection part 111 (see FIG. 13). The first liquid storage chamber 401 is provided on the upstream side of the liquid flow, which is the side to which the liquid ejection head 3 is connected, in the pressure control unit 2230 in which the pressure adjustment mechanism is provided, and the second liquid storage chamber 403 is located downstream of the flow as viewed from the first liquid storage chamber 401. Eventually, the liquid that flows into the first liquid storage chamber 401 from the common recovery channel 211 or the common supply channel 212 via the inlet 414 flows into the valve chamber 402 in the first liquid storage chamber 401, and further flows into the second liquid storage chamber 403 via the outlet 410. The liquid is then guided to the second circulation pump 1004 via the liquid connection part 111.

[0048] As shown in FIG. 14(a), the outlet 410 is preferably formed at a position vertically above the portion of the outer wall of the first liquid storage chamber 401 formed of the flexible film 405. By forming the valve chamber 402 and the outlet 410, which are arranged downstream of the first liquid storage chamber 401 in the flow direction, vertically above in this manner, it becomes easier to discharge air from within the first liquid storage chamber 401 when filling the first liquid storage chamber 401 with liquid. If the air is sufficiently discharged when filling the first liquid storage chamber 401 with liquid, it is possible to suppress a change in the amount of air inside the first liquid storage chamber 401 when the pressure adjustment mechanism is used, which causes a change in the head pressure of the first liquid storage chamber 401. Furthermore, by configuring in this manner, it is possible to suppress a change in the pump pressure caused by air discharged from the first liquid storage chamber 401 flowing into the second circulation pump 1004 while the pressure adjustment mechanism is being used. Furthermore, in this configuration, when air flows into the first liquid storage chamber 401, the air is less likely to remain in the portion of the first liquid storage chamber 401 formed by the flexible film 405, and is more likely to remain in the valve chamber 402 or be discharged from the outlet 410. In general, a thin member such as the flexible film 405 has high gas permeability, and if air remains in the portion formed by the flexible film 405, the volume of the remaining air is likely to increase due to gas permeation. If the volume of the remaining air increases, there is a risk that the head pressure of the first liquid storage chamber 401 will change, or the pump pressure will change due to the air flowing into the second circulation pump 1004. For this reason, it is preferable to provide the outlet 410 vertically above the portion formed by the flexible film 405, so that the remaining air is less likely to remain near the inside of the outer wall formed by the flexible film 405.

[0049] Next, the valve 406 disposed in the valve chamber 402 will be described. The valve 406 is formed of a seal member based on the present invention. FIG. 15(a) and FIG. 15(b) show the valve 406 enlarged as viewed from different angles. The valve 406 is formed in a lever shape as a lever portion 503, which will be described later, and is rotatable around a shaft 408 fitted in a bearing (not shown) of the pressure adjustment mechanism. A valve portion 407 acting as a valve body of the valve 406 is provided at one end of the valve 406. By forming a variable gap 413 (see FIG. 14(b)) between the valve portion 407 and the outlet 410, it is possible to provide a variable flow resistance to the liquid flowing from the valve chamber 402 to the second liquid storage chamber 403 through the outlet 410, which is an opening. The size of the gap 413, which is the distance between the valve portion 407 and the outlet 410, is the valve opening degree, and the larger the gap 413, the higher the valve opening degree and the smaller the flow resistance. Furthermore, a valve spring 412 is disposed as a second biasing member in the valve chamber 402. The valve spring 412 biases the valve portion 407 in a direction that reduces a gap 413 between the valve portion 407 and the outlet 410, i.e., in a direction that causes the valve portion 407 to close the outlet 410.

[0050] Meanwhile, a pressure plate contact portion 409 is formed on the other end of the valve 406, which is located on the opposite side of the valve portion 407 across the shaft 408. The pressure plate contact portion 409 transmits the movement of the flexible film 405 and the pressure plate 404 in the first liquid storage chamber 401 to the valve 406. When the flexible film 405 and the pressure plate 404 move, i.e., are displaced, in accordance with the volume of the first liquid storage chamber 401, a part of the pressure plate 404 comes into contact with the pressure plate contact portion 409, and the valve 406 moves so as to rotate in conjunction with the movement of the pressure plate 404. In FIG. 14(b), the arrow indicates how the valve 406 rotates in the direction in which the gap 413 between the valve portion 407 of the valve 406 and the outlet 410 increases, i.e., in the direction in which the valve opening at the outlet 410 increases.

[0051] When the pressing plate 404 moves in a direction to increase the volume of the first liquid storage chamber 401, the pressing plate contact portion 409 in contact with the pressing plate 404 moves to rotate about the shaft 408. This movement moves the valve portion 407 away from the outlet 410, increasing the gap 413 between the outlet 410 and the valve, and increasing the valve opening degree of the outlet 410. In other words, when the pressing plate 404 is displaced in a direction to expand the first liquid storage chamber 401, the valve portion 407, which is an elastic member, moves away from the outlet 410, decreasing the flow resistance to the liquid flowing out through the outlet 410. Conversely, when the pressing plate 404 moves in a direction to decrease the volume of the first liquid storage chamber 401, the pressing plate contact portion 409 in contact with the pressing plate 404 moves to rotate about the shaft 408 of the valve 406. This movement reduces gap 413 between valve portion 407 and outlet 410, decreasing the valve opening at outlet 410 and increasing flow resistance. In this manner, movement of flexible film 405 and pressure plate 404 causes valve 406 to move, and gap 413 between valve portion 407 and outlet 410, i.e., the valve opening at outlet 410, changes.

[0052] In this way, the valve opening at the outlet 410 and the flow resistance to the liquid at the outlet 410 change depending on the movement of the valve 406. The valve 406 moves in contact with the pressing plate 404 at the pressing plate contact portion 409. The valve 406 has a range of movement (movable range) limited by the shaft 408 and a bearing that fits on the shaft 408, and performs a rotational movement that is a movement limited by these. That is, the valve 406 moves so that the valve opening increases in conjunction with the expansion of the first liquid storage chamber 401, but the range of this movement is limited to a preset range. Therefore, even if there is an influence of the flexible film 405 and the pressing plate 404, the gap 413 between the valve portion 407 and the outlet 410, which is the valve opening of the outlet 410, can have a desired value.

[0053] In contrast, consider a case where the liquid storage chamber (pressure chamber) is formed by the flexible film 405 and the pressure plate 404, the valve is formed integrally with the flexible film 405 and the pressure plate 404, and the movable range of the valve is not limited by anything other than the pressure plate 404. In this case, the movement of the valve is easily affected by the rigidity of the flexible film 405 itself, and by folds and wrinkles formed on the flexible film 405. For example, due to the influence of wrinkles on the flexible film 405, the pressure plate 404 may move in an inclined state, and the valve opening degree at the outlet 410 may not be a desired value. In contrast, in this embodiment, the movable range of the valve 406 is limited by a member other than the pressure plate 404, so that the valve opening degree at the outlet 410 can be a predetermined value regardless of the state of the flexible film 405 and the pressure plate 404. Therefore, in this embodiment, the influence of the flexible film 405 on the control of the liquid pressure by the valve 406 is reduced, and stable pressure control can be performed.

[0054] As shown in FIG. 15, the shape of the pressure plate contact portion 409 provided on the valve 406 is preferably at least a part of a sphere. FIG. 15 shows the pressure plate contact portion 409 having a hemispherical shape. FIG. 16 shows an example of the inclination of the pressure plate 404, in which FIG. 16(a) shows a state without inclination, and FIG. 16(b) shows a state in which the pressure plate 404 has moved so as to incline from the state shown in FIG. 16(a). By making the shape of the pressure plate contact portion 409 at least a part of a sphere, even if the pressure plate 404 is displaced in a tilted state as shown in FIG. 16(b), the pressure plate 404 and the pressure plate contact portion 409 come into contact with each other at one point on the spherical surface. Therefore, the load point of the valve 406 is constant, and the valve 406 can operate stably.

[0055] Next, the stabilization of the pressure in the first liquid storage chamber 401, that is, the back pressure, in the pressure adjustment mechanism will be described. The pressure in the first liquid storage chamber 401 is determined by the following relational expression. (F1+P1·S1)L1=(F2-(P2-P1)S2)L2 …(1) (P1-P2)=R·Q …(2) where: P1: pressure (gauge pressure) inside the first liquid storage chamber 401, P2: pressure inside the second liquid storage chamber 403 (gauge pressure), F1: spring force of negative pressure spring 411, F2: spring force of valve spring 412, S1: pressure receiving area of ​​the pressure plate 404, S2: pressure-receiving area of ​​the valve portion 407, L1: arm length 1 of lever portion 503 (length from shaft 408 to pressure plate contact portion 409), L2: arm length 2 of lever portion 503 (length from shaft 408 to valve portion 407), R: flow resistance of the gap 413 between the valve portion 407 and the outlet 410; Q: Liquid flow rate.

[0056] Here, for simplicity, it is assumed that the pressure in the valve chamber 402 is equal to the pressure in the first liquid storage chamber 401. The flow resistance R of the gap 413 between the valve portion 407 and the outlet 410 varies depending on the size of the gap 413. The larger the gap 413 is, that is, the greater the distance between the valve 407 and the outlet 410, the smaller the flow resistance R is. Equation (1) represents the balance of forces in the valve 406, and equation (2) represents that the product of the flow resistance and the flow rate is equal to the pressure difference. The size of the gap 413 is determined so that the above equations (1) and (2) are simultaneously satisfied, and thereby pressure P1, that is, the back pressure of the pressure adjustment mechanism, is derived.

[0057] For example, in the liquid ejection device 2000 equipped with a pressure adjustment mechanism, when the flow rate Q of the liquid flowing into the pressure adjustment mechanism increases, the following occurs. The pressure P2 in the second liquid storage chamber 403 increases due to the pressure characteristics according to the flow rate of the second circulation pump 1004 arranged downstream of the pressure adjustment mechanism and the increase in flow resistance of the path from the second liquid storage chamber 403 to the second circulation pump 1004. This pressure P2 is the pressure on the suction side of the second circulation pump 1004, so the pressure P2 approaches a positive pressure. When the pressure P2 increases, the pressure P1 instantaneously decreases according to formula (1). At this time, the flow rate Q and pressure P2 increase, while the pressure P1 decreases, so according to formula (2), the valve 406 is displaced so that the flow resistance R decreases. Since the flow resistance R decreases, the gap 413 between the valve portion 407 and the outlet 410 needs to increase, and the valve 406 rotates and displaces in the direction in which the gap 413 increases. As a result of this displacement, the valve spring 12 is displaced in a direction in which its spring length decreases, and the spring force F2 increases. On the other hand, the load spring 411 on the pressing plate 404 side is displaced in a direction in which its spring length increases, and the spring force F1 decreases. At this time, the pressing plate 404 is displaced in a direction in which the volume of the first liquid storage chamber 401 increases. As a result, the pressure P1 increases instantaneously according to equation (1). When the pressure P1 increases, the pressure P2 decreases instantaneously due to the opposite action to that described above. This phenomenon is repeated in a short period of time, and since equations (1) and (2) must be satisfied simultaneously while the flow resistance R changes according to the flow rate Q, the back pressure, or pressure P1, is maintained within a certain pressure range.

[0058] In the liquid ejection device 2000, the first liquid storage chamber 401 of the pressure adjustment mechanism communicates with the liquid recovery channel 212 and the ejection module 300 via the inlet 414. Here, the pressure P1, which is the back pressure, is maintained within a certain range, so that the pressure of the ejection module 300 related to the ejection of liquid is maintained within a certain range. The gap 413 between the valve portion 407 and the outlet 410 plays a major role in maintaining the pressure P1 within the certain range. For example, assume that the valve portion 407 is in a positional relationship that is significantly inclined relative to the outlet 410. In such a case, it becomes impossible to form the gap 413 large enough to provide the flow resistance R that satisfies both of the formulas (1) and (2), and therefore it becomes impossible to maintain the pressure P1 within a certain range.

[0059] The valve 406 described above has a valve portion 407 functioning as a valve body at one end and a pressure plate contact portion 409 at the other end, but the valve 406, which is a sealing member based on the present invention, is not limited to such a configuration. For example, the valve may be a valve that rotates and displaces around one end of the valve, or may be a valve that changes the size of the gap 413 between the valve portion 407 and the outlet 410 by linear displacement rather than rotation. The valve opening at the outlet 410 indicates the ease of flow of the liquid taking into account the flow resistance at the outlet 410. If the gap 413 at the outlet 410 becomes larger, the valve opening becomes higher. The valve opening also becomes higher when the opening area of ​​the outlet 410 itself becomes larger. The valve opening also becomes higher when the valve moves from a state in which the outlet 410 is closed by the valve (valve opening is 0%) to a state in which at least a part of the outlet 410 is opened.

[0060] It is preferable that the pressure adjustment mechanism is such that the direction of movement of the valve 406, particularly the direction of movement of the valve portion 407, which is a valve body, is different from the direction of displacement of the flexible film 405. If the direction of displacement of the flexible film 405 and the direction of movement of the valve portion 407 are the same, the restriction of the movable range of the valve 406 by members other than the pressing plate 404 is likely to directly affect the movements of the flexible film 405 and the pressing plate 404. This may make it difficult for the flexible film 405 and the pressing plate 404 to move as desired. On the other hand, if the direction of displacement of the flexible film 405 and the direction of movement of the valve portion 407 are different, the restriction of the movable range of the valve 406 by members other than the pressing plate 404 is unlikely to directly affect the movements of the flexible film 405 and the pressing plate 404. This makes it easier for the flexible film 405 and the pressing plate 404 to move as desired.

[0061] Moreover, the pressure adjustment mechanism is preferably configured such that the flexible film 405 and the pressure plate 404 are displaced linearly, and the movement of the valve 406 linked thereto is rotational. If the movement of the valve 406 is rotational, it is easy to limit the movable range of the valve 406 by a member other than the pressure plate 404, for example by fixing the axis of rotation. In particular, in a configuration in which the outlet 410 is located vertically above the first liquid storage chamber 401, it is more preferable that the movement of the valve 406 is rotational. If the movement of the valve 406 is rotational, the gap width becomes larger at the upper part in the vertical direction in the gap 413 between the valve portion 407 and the outlet 410 when the valve opening degree increases. If the gap width is wider at the upper part in the vertical direction, air that tends to accumulate at a vertically upper position in the valve chamber 402 is easily allowed to flow out of the outlet 410 via the gap 413.

[0062] In the above explanation, the valve opening at outlet 410 has been explained using the change in flow resistance depending on the size of gap 413 in the direction in which valve portion 407 and outlet 410 face each other, but the present invention is not limited to this. For example, the flow resistance may be changed by displacing valve portion 407 so as to change the opening area of ​​outlet 410 itself. In any case, the movable range of valve 406, which is a sealing member based on the present invention, is limited by a member other than pressure plate 404, so that flexible film 405 is unlikely to affect the control of the liquid pressure by valve 406.

[0063] Next, an example of the movement of the pressure plate 404 and the valve 406, which is different from the example described in FIG. 14, will be described with reference to FIG. 17. FIG. 17(a) is a cross-sectional view showing a pressure adjustment mechanism in this case. In the example shown in FIG. 17, the pressure plate 404 rotates and moves in a direction to increase the volume of the first liquid storage chamber 401. In FIG. 17(a), an axis located at the center of the negative pressure spring 411, which is a biasing member, is shown as axis (i), and an axis passing through the vertical center of the flexible film 405 and the pressure plate 404, which constitute the movable part in the first liquid storage chamber 401, is shown as axis (ii). Both axis (i) and axis (ii) are axes perpendicular to the vertical direction, but axis (i) is disposed vertically above axis (ii). A pressure plate protrusion 422 is provided at the lower end of the pressure plate 404 in the vertical direction. Furthermore, a pressure plate restricting portion 421 is provided at a position facing the pressure plate protrusion 422 inside the first liquid storage chamber 401. When the movable portion of the first liquid storage chamber 401 is displaced, the pressure plate restricting portion 421 restricts the pressure plate protrusion 422 from being displaced in the length direction (extension direction) of the negative pressure spring 411 by the pressure plate protrusion 422 of the pressure plate 404 coming into contact with the pressure plate restricting portion 421.

[0064] 17(b), when the volume of the first liquid storage chamber 401 increases, the movable part of the first liquid storage chamber 401 moves so as to rotate and displace in the direction indicated by the arrow. That is, due to the balance between the pressure in the first liquid storage chamber 401 and the spring force of the negative pressure spring 411, the movable part of the first liquid storage chamber 401 rotates and displaces around the pressure plate protrusion 422 as the center of rotation from a state in which the pressure plate protrusion 422 abuts against the pressure plate regulating portion 421. In this configuration, the state of the flexible film 405 of the first liquid storage chamber 401 and the pressure plate 404 when the valve 406 is opened is restricted to a state in which the pressure plate protrusion 422 abuts against the pressure plate regulating portion 421. Therefore, the force with which the negative pressure spring 411 presses the pressure plate 404 when the valve 406 is opened can also be kept constant. Since the pressing force of the negative pressure spring 411 is a parameter that determines the pressure in the first liquid storage chamber 401 as described above, the pressure in the first liquid storage chamber 401 can be made constant by keeping the pressing force of the negative pressure spring 411 constant. Since the pressing plate protrusion 422 is restricted to a state in which it abuts against the pressing plate restricting portion 421, the deformation state of the flexible film 405 and the pressing plate 404, which are the movable parts, becomes constant when the valve 406 is opened. In other words, the pressure-receiving area of ​​these movable parts becomes constant. Since the pressure-receiving area of ​​the movable part is a parameter that determines the pressure in the first liquid storage chamber 401 as described above, the pressure-receiving area of ​​the movable part becomes constant by keeping the pressure-receiving area of ​​the movable part constant.

[0065] (Configuration of the valve as a sealing member) Next, the valve portion 407 and the lever portion 503 in the valve 406 will be described in detail. FIG. 18 is an enlarged view of the main portion of the valve 406, showing a cross section taken along the line BB in FIG. 13(a). As described above, the valve 406 is an example of a seal member based on the present invention, the valve portion 407 corresponds to the elastic member in the seal member, and the lever portion 503 corresponds to the base member in the seal member. The valve 406 is lever-shaped, and the portion of the valve 406 excluding the valve portion 407 becomes the lever portion 503. The valve portion 407 is fixed to the lever portion 503. As shown in FIG. 15 and FIG. 18, the valve tip portion 501, which is a part of the valve portion 407, has an annular protrusion shape surrounding the outer periphery of the outlet 410, and forms a cap 413 between the gap forming surface 502 around the outlet 410 to provide a variable flow resistance. When the flow rate through the outlet is made very small, the flow resistance needs to be extremely large, and the gap 413 needs to be a very small gap. However, if the valve tip 501 and the gap forming surface 502 that form the gap 113 are inclined, wavy, or uneven, a gap will remain even if they come into contact with each other, making it difficult to further reduce the gap 113. For this reason, in this embodiment, the valve tip 501 is made of an elastic member that is a soft material, and the valve tip 501 is adapted to conform to the surface shape of the gap forming surface 502. This makes it possible to absorb the inclination, wavy, and unevenness of the surface of the gap forming surface 502, and to form an extremely small gap 513. The valve tip 501 having an annular protrusion shape is an example of an annular abutment portion. The reason why the valve tip 501, which is a part of the valve portion 407 that is an elastic member, is provided in an annular shape will be described later.

[0066] As shown in FIG. 14(b), the lever portion 503 is subjected to a pressing pressure from the pressing plate 404 received by the pressing plate contact portion 409, a reduced pressure in the second liquid storage chamber 403 received by the valve portion 407, and a spring load of the valve spring 412. These forces cause the lever portion 503 to receive a bending moment with the axis 408 as the center of rotation. When the lever portion 503 is deformed, the relationship between the size of the gap 413 and the position of the pressing plate 404 deviates from the original relationship. When the position of the pressing plate 404 changes with the deformation of the lever portion 503, the pressure receiving area of ​​the pressing plate 404 and the load of the negative pressure spring 411 change, and the pressure in the first liquid storage chamber 401 also changes. In order to reduce the pressure change in the first liquid storage chamber 401 over a long period of time, the lever portion 503 of the valve 406, including the axis 408, is required to have high rigidity. In particular, when the pressure adjustment mechanism is used to adjust the pressure of heated liquid, the lever portion 503 is preferably made of a material with high heat resistance, since an increase in temperature reduces rigidity and increases deformation. For example, in the case of a pressure adjustment mechanism provided in a liquid ejection device, there is a high possibility that liquid whose temperature has risen to 30° C. or higher will flow into the pressure adjustment mechanism due to an increase in temperature within the device, temperature adjustment of the recording liquid, heat generation in the recording element substrate, and the like. If the rigidity of the lever portion 503 decreases due to the inflow of the heated liquid, and the deflection and deformation of the lever portion 503 increases, the back pressure to be maintained by the pressure adjustment mechanism will fluctuate, and as a result, there is a risk of a decrease in recording quality when the recording liquid is ejected as a liquid.

[0067] Next, the fixing of the valve portion 407, which is an elastic member, to the lever portion 503 will be described. Since the pressure adjustment mechanism described here is of the back pressure type, the second liquid storage chamber 403 is depressurized by a pump connected thereto (second circulation pump 1004 in the case of use in the third circulation mode shown in FIG. 12). When the second liquid storage chamber 403 is depressurized, a force in a direction narrowing the gap 413 is applied to a region including the valve tip portion 501 and at the tip of the valve 460 facing the outlet 410. Meanwhile, a force in a direction widening the gap 413 is applied to the lever portion 503 from the pressing plate 404. Therefore, a force in a direction peeling the valve portion 407 away from the lever portion 503 is applied to the valve portion 407 by the depressurization pressure from the second liquid storage chamber 403 side. As an example, the minimum pressure applied to the valve portion 507 as the depressurization pressure is −5 kPa or less (since it is a negative pressure here, the absolute value of the applied pressure is 5 kPa or more). If gap 413 is sufficiently small compared to the size of valve 406, the force in the direction narrowing gap 413 is limited to the area facing outlet 410 and its periphery. Therefore, if valve tip 501 is formed in an annular shape so that it can abut against gap forming surface 502 at a position along the edge of outlet 410, it is possible to keep the area receiving the reduced pressure small, to only annular valve tip 501. If the area receiving the reduced pressure is narrowed, the peeling force applied to valve portion 407 from lever portion 503 is also reduced, so that there is less risk that valve 407, which is an elastic member, will be peeled off from lever portion 503, which is made of a highly rigid material. Therefore, valve tip 501 is preferably formed as an annular abutment portion.

[0068] An adhesive may be used as a means for joining valve portion 407 to lever portion 503. However, when using an adhesive, it is difficult to select an adhesive suitable for joining lever portion 503, which is a base member made of a highly rigid material, to valve portion 407, which is an elastic member made of a soft material, and there is also a risk of components contained in the adhesive eluting. For example, if a pressure adjustment mechanism in which valve portion 407 is joined to lever portion 503 using an adhesive is applied to a liquid ejection device, there is a risk that adhesive components will elute into the recording liquid, etc., generating foreign matter in the recording liquid and causing clogging of the ejection port.

[0069] In this embodiment, in order to fix the valve portion 407 to the lever portion 503 without using adhesive, a configuration is adopted in which the valve portion 407 is held by an annular groove formed in the lever portion 503. As shown in FIG. 18, the valve portion 407 has a tubular held portion 505 extending from the valve tip portion 501 in the depth direction of the lever portion 503 in addition to the valve tip portion 501 formed in an annular shape. The held portion 505 is fixed such that both side surfaces thereof are sandwiched between a pair of side surfaces 504 of an annular groove 535 formed in the lever portion 503. In FIG. 18, the annular groove 535 is not shown separately because the held portion 505 already exists inside the annular groove 535, but FIG. 19(b) shows the lever portion 503 before the valve portion 407 is fixed, and also shows the annular groove 535. The valve tip portion 501 and the held portion 505 are formed integrally, and the valve portion 407 has an overall cylindrical shape as an elastic member made of a soft material. The part of valve portion 407 protruding from lever portion 503 is valve tip portion 501, and the tubular portion embedded inside lever portion 503 is held portion 505. Valve 406 including lever portion 503 and valve portion 407 can be manufactured by, for example, two-color molding. When two-color molding is used, lever portion 503 is first formed by primary molding, and then valve portion 407 is molded by secondary molding by injecting resin at high pressure into annular groove 535 formed in lever portion 503, which is a base member. As a result, valve portion 407 is sandwiched between a pair of side surfaces 504 of annular groove 535 of lever portion 503, and is fixed in close contact with these side surfaces 504. In the region where valve portion 407 is fixed so as to be sandwiched, valve portion 407 is in direct contact with lever portion 503, which is a base member.

[0070] In order to prevent the valve portion 407 from falling off from the lever portion 503, in this embodiment, the length by which the annular groove 535 holds the held portion 505 along the depth direction of the lever portion 503, i.e., the holding length 514, is made longer than the width 513 of the annular groove. Specifically, it is preferable that the holding length 514 is twice or more the width 513 of the annular groove. The width of the annular groove 535 is the distance between a pair of opposing side surfaces 504 of the annular groove 535, and when the annular groove 535 has a tapered shape as described later, it is the width at the upper end side of the annular groove 535. In this embodiment, the pressure receiving area of ​​the reduced pressure forming the valve tip portion 501 as the annular abutment portion is made small, and further, the relationship between the width 513 of the annular groove 535 and the holding length 514 is determined to further increase the reliability of the fixation of the valve portion 407 to the lever portion 503. Furthermore, in this valve 406, even if a material has low compatibility with the material constituting the valve portion 407, which is the elastic member, it can be used for the lever portion 503, which is the base member, thereby expanding the material selection options for the valve portion 407 and the lever portion 503.

[0071] When manufacturing the valve 406 by injection molding including two-color molding, the distance between the pair of side surfaces 504 of the annular groove 535 in the lever portion 503 needs to narrow toward the depth direction of the lever portion 503, considering that the mold will be opened after molding. That is, the cross-sectional shape of the annular groove 535 of the lever portion 503 needs to be tapered. However, from the viewpoint of preventing the valve portion 407 from falling off from the lever portion 503, it is preferable that the angle formed by the pair of opposing side surfaces 504 (i.e., the taper angle) is 20° or less. Note that the angle formed by the pair of side surfaces 504 refers to the angle formed by the pair of side surfaces 504 in the cross section of the lever portion 503 on a plane that includes a straight line that passes through a point along the annular groove 535 and extends in the width direction of the annular groove 535 at that point, and is parallel to the depth direction of the lever portion 503. Furthermore, by using a resin material constituting lever portion (base member) 503 that has a smaller molding shrinkage rate than the resin material constituting valve portion 407, the force with which valve portion 407 tightens against inner side surface 504 of annular groove 535 due to shrinkage after injection molding can be made stronger, thereby increasing the fixing strength.

[0072] In order to further increase the fixing strength of the valve portion 407 to the lever portion 503, the valve portion 407 may be provided with reinforcing portions 506 extending outward from the annular valve tip portion 501 and the held portion 505 as shown in FIG. 15. The lever portion 503 holds at least a part of the reinforcing portion 506 by a groove formed in the lever portion 503, just as a pair of side surfaces 504 of the annular portion 535 holds the held portion 505 of the valve portion 407. By providing the reinforcing portion 506, the area of ​​direct contact between the lever portion 503 and the valve portion 407 for holding the valve portion 407 becomes larger, and the fixing strength of the valve portion 407 to the lever portion 503 is further increased. If necessary, a plurality of reinforcing portions 506 may be provided so as to extend radially from the valve portion 407 as a center.

[0073] In this way, in the valve 406, a flexible elastic material is required for the valve portion 407 which is an elastic member, and a highly rigid material is required for the lever portion 503 which is a base member. Since materials with different performances are used in this way, assembly is necessary. In assembling the valve 406, it is important to assemble the valve tip portion 501 and the lever portion 503, particularly the shaft 408 and the pressing plate contact portion 409, with high precision so that the positional relationship between the gap 413 and the pressing plate 404 does not change. In addition, when the valve portion 407 is fixed to the lever portion 503, it is necessary to prevent the valve tip portion 501 from undulating or deforming. In order to meet such requirements, the valve portion 407 and the lever portion 503 are both made of a material which can be injection molded, and are assembled and molded integrally in a mold by two-color molding, which is a method of injection molding, so that the valve 406 can be molded and assembled with high precision. Hereinafter, a method of molding and assembling the valve portion 407 which is an elastic member and the lever portion 503 which is a base member by two-color molding will be described with reference to Figs. 19 to 21. Fig. 19(a) is an enlarged view of the vicinity of valve portion 407 in the cross section taken along line CC in Fig. 15, showing the state after molding and assembly are completed. Fig. 19(b) is a cross-sectional view of lever portion 503 upon completion of primary molding, and Fig. 19(c) is a cross-sectional view showing the state midway through resin filling in secondary molding.

[0074] When forming the valve 406 by two-color molding, first, only the lever portion 503 is molded by primary molding. By primary molding, an annular groove 535 is formed in the lever portion 503. When the primary molding is completed, the fixed side mold 519 and the movable side mold 518 used in the primary molding are opened at the mold mating surface shown by the dashed line in FIG. 19(b). At that time, the lever portion 503 is in a state of being attached to the movable side mold 518. After that, in order to perform secondary molding, the movable side mold 518 moves together with the lever portion 503 in front of the fixed side mold 520 for secondary molding, and the mold is closed. As a result, the fixed side mold 520 for secondary molding abuts against the lever portion 503 that has already been molded. After that, as shown in FIG. 19(c), the resin for secondary molding is injected and filled from the secondary molding gate 510 into the space formed by the lever portion 503 and the fixed side mold 520. As shown in FIG. 19(a), the fixed mold 520 is provided with a resin introduction path 508 extending in the gate direction at a position corresponding to the valve tip 501. The resin that enters the mold from the gate 510 flows from the resin introduction port 509 through the resin introduction path 508 and is gradually filled into the valve tip 501 as shown by the arrow in FIG. 19(a). FIG. 20 is an enlarged view of the part where the valve part 407 of the valve 406 is provided, that is, the part where the annular abutment part is formed, and shows the position of the gate 510 used in secondary molding and the resin introduction path 508 after molding. If the resin introduction path 508 is not provided, the valve tip 511 is narrow and cut up as shown in FIG. 21, so that the resin from the resin introduction port 509 is difficult to fill the position corresponding to the valve tip 501, and gas is likely to remain. If gas remains, a dent occurs in the valve tip 501, which is the annular abutment part. If such a recess is present, there is a possibility that the valve tip portion 501 and the gap forming surface 502 will not come into contact with each other without any gap, and the back pressure type pressure adjustment mechanism may not function sufficiently. Therefore, it is preferable to provide a resin introduction path 508. Since the resin filled in the resin introduction path 508 remains even after molding, the resin in the resin introduction path 508 may be used as the reinforcing portion 506 described above.The position where resin introduction path 508 connects to valve tip portion 501 is preferably as close to the tip of valve tip portion 501 as possible, and is preferably the protrusion tip portion of valve tip portion 501, which is an annular protrusion. Also, angle 512 formed by the direction in which resin introduction path 508 extends with respect to plane α spanned by the protrusion tip portion is preferably smaller than angle 511 (see FIG. 18) formed by plane α and the outer surface of valve tip portion 501 at the protrusion tip portion, and is more preferably 30° or less.

[0075] In this embodiment, an annular groove 535 is formed in the lever portion 503, and the valve portion 407 is held by both side surfaces 504 of the annular groove 535. In the lever portion 503, a through hole 522 for venting is provided at the bottom 521 of the annular groove 535. When the valve portion 407, which is an elastic member, is injection molded, gas is likely to remain in the final filled portion of the resin. If there is residual gas, there is a risk that the lever portion 503 of the valve portion 407 will fall off, or that the valve portion 407 will be deformed due to the expansion of the remaining gas caused by temperature changes. By providing the through hole 522, the gas in the final filled portion can be released to the movable side mold 518. This reduces the amount of residual gas. Even when the valve portion 407 and the lever portion 503 are molded and assembled separately without using two-color molding, if there is the through hole 522, the air remaining in the space between the valve portion 407 and the lever portion 503 during assembly can be released, and defects due to the expansion of the air can be prevented.

[0076] By assembling and molding the lever portion 503 and the valve portion 407 by injection molding in this manner, the accuracy of the position of the valve tip portion 501 in the lever portion 503 is determined by the mold, so that the valve 406 can be assembled with high accuracy. As a resin material for molding the valve portion 407, for example, a styrene-based elastomer, which is a thermoplastic elastomer, can be mentioned. As a resin material for molding the lever portion 503, which is a base member that requires high rigidity, modified polyphenylene ether is preferable, and polystyrene, polyolefin, filler, etc. may be added thereto. As a method for forming the valve 406, the assembly method by two-color molding is one example, and assembly may be performed by insert molding in which the molded lever portion 503 is inserted into a mold and the valve portion 407 is molded. As another assembly method, there is a method in which the valve portion 407 and the lever portion 503 are molded separately, heat is applied to the held portion 505 of the valve portion 407 to soften it, and the held portion 505 is inserted into the annular groove 535 that is formed in advance in the lever portion 503. The materials and assembly methods described above are merely examples, and the present invention is not limited to these.

[0077] (Reduced pressure adjustment mechanism) The above describes the case where the seal member according to the present invention is used as a valve for adjusting pressure loss to control back pressure in a back pressure type pressure adjustment mechanism, but the present invention is not limited to this. The seal member according to the present invention can also be used in a pressure reduction type pressure adjustment mechanism, various valves such as a check valve, and a gasket for sealing. Hereinafter, the case where the seal member according to the present invention is used as a valve in a pressure reduction type pressure adjustment mechanism will be described. FIG. 22(a) is an external perspective view showing a pressure reduction type pressure adjustment mechanism, and FIG. 22(b) is a cross-sectional view taken along line DD in FIG. 22(a). The pressure reduction type pressure adjustment mechanism described here can be used, for example, in the pressure control unit 230 in the first circulation mode shown in FIG. 2.

[0078] Like the back pressure type pressure adjustment mechanism described above, the pressure reduction type pressure adjustment mechanism also includes a first liquid storage chamber 401, a second liquid storage chamber 403, a pressure plate 404, a flexible film 405, a valve 406, a negative pressure spring 411, a valve spring 412, etc. The pressure plate 404 is fixed by the flexible film 405 and biased by the negative pressure spring 411, and is displaced according to an increase or decrease in the amount of liquid in the first liquid storage chamber 401. The valve 406, which is a sealing member, is biased by the valve spring 412 in a direction to close an opening 430 that communicates from the second liquid storage chamber 403 to the first liquid storage chamber 401. Because it is a pressure reduction type, the amount of flow needs to be controlled according to the pressure downstream of the flow, and the liquid flows in a direction from the second liquid storage chamber 403 toward the first liquid storage chamber 401. When the inside of first liquid storage chamber 401 contracts, pressing plate 404 presses valve 406 against the biasing force of valve spring 412, causing valve 406 to move away from opening 430 between second liquid storage chamber 403 and first liquid storage chamber 401, thereby reducing flow resistance at opening 430. In other words, in this pressure adjustment mechanism, when pressing plate 404 is displaced in a direction that expands first liquid storage chamber 401, elastic member 516 approaches opening 430, increasing flow resistance to liquid flowing out through opening 430. This pressure adjustment mechanism operates to keep the pressure of the liquid in first liquid storage chamber 401 constant, because when the pressure in first liquid storage chamber 401 increases, first liquid storage chamber 401 expands, and flow resistance to liquid flowing into first liquid storage chamber 401 through opening 430 increases.

[0079] Fig. 23(a) is an external perspective view of the valve 406 used in the pressure reducing type pressure adjustment mechanism shown in Fig. 22, and Fig. 23(b) is a cross-sectional view taken along the line EE in Fig. 23(a). The valve 406 is generally configured in the shape of a body of revolution with the line EE as its central axis, and is made up of a base member 515 including a pressing plate contact portion 530 and an elastic member 516 equipped with a reinforcing portion 506. The base member 515 is substantially cylindrical, and a rod-shaped pressing plate contact portion 530 extends from one end of the base member 515 along the central axis of the valve 406. The pressing plate contact portion 530 is provided so as to come into contact with the pressing plate 404 and move the valve 406 in response to the displacement of the pressing plate 404. The substantially cylindrical elastic member 516 is joined and fixed to the base member 515 so as to be coaxial with the base member 515. One end of the elastic member 516 protrudes as an annular protrusion from the base member 515 so as to surround the pressing plate contact portion 530, and forms the valve tip portion 501 which is an annular abutment portion. The remaining portion of the elastic member 516 is embedded in an annular groove formed in the base member 515 as the held portion 505, and is held by being sandwiched between a pair of side surfaces 504 of the annular groove. Here too, the holding length, which is the length by which the annular groove holds the held portion 505 along the depth direction of the base member 515, is longer than the width of the annular groove, and the adhesion of the held portion 505 to the base member 515 is increased. In addition, the elastic member 516 is provided with a reinforcing portion 506, and the base member 515 also holds the reinforcing portion 506, thereby increasing the fixing strength and reducing the risk of the elastic member 516 falling off the base member 515. In addition, even if a material that is less compatible with the material constituting the elastic member 516 is used for the base member 515, the material selection for the base member 515 can be expanded. A decompression type pressure adjustment mechanism that has high reliability over a long period of time can be configured by using a high-strength material for the base member 515. In addition, since the components can be made smaller, the pressure adjustment mechanism can also be made smaller, which in turn enables the miniaturization of a liquid ejection device or the like that includes the pressure adjustment mechanism.

[0080] (Cap material) Next, another application of the seal member according to the present invention will be described. The seal member according to the present invention can also be used as a cap member that covers the liquid discharge head when not in use or on standby in a liquid discharge device to suppress evaporation of the recording liquid from the discharge port. FIG. 24(a) is a perspective view of a cap member made of the seal member according to the present invention, and FIG. 24(b) is a cross-sectional view taken along the line FF in FIG. 24(a). By contacting an annular elastic member 516 with the surface of the liquid discharge head on which the discharge port is formed, the cap member covers the liquid discharge head and suppresses evaporation of the recording liquid from the discharge port. In addition, by reducing the pressure inside the space surrounded by the annular elastic member 516 with a pump, it is also possible to suck the recording liquid from the liquid discharge head and remove foreign matter present near the discharge port. The elastic member 516 is fixed to the base member 515 as described above. Furthermore, in the cap member, the elastic member 516 is provided with a reinforcing portion 517, and the base member 515 holds at least a part of the reinforcing portion 517, thereby further reducing the risk of the elastic member 516 falling off from the base member 515. With this cap member as well, it is possible to select a material with high rigidity for the base member 515 while preventing the elastic member 516 from falling off from the base member 515, and as a result, it is possible to increase the reliability of the cap member. [Explanation of symbols]

[0081] 406 Valve 407 Valve section 410 Outlet 413 Gap 501 Valve tip 503 Base material 504 Side 505 Holding part 513 Width of annular groove 514 Retention Length 535 Circular Groove

Claims

1. an elastic member having an annular contact portion formed as an annular protrusion; a base member to which the elastic member is fixed; having the elastic member is fixed to the base member by a tubular held portion extending from the annular abutment portion being held by an annular groove formed in the base member, and a holding length, which is a length along which the annular groove holds the held portion in a depth direction of the base member, is longer than a width of the annular groove; A sealing member, characterized in that the elastic member has a reinforcing portion extending from the held portion, and at least a portion of the reinforcing portion is held by a groove formed in the base member.

2. The seal member according to claim 1 , wherein a pair of side surfaces of the annular groove and the held portion of the elastic member are in direct contact with each other.

3. 3. The sealing member according to claim 1, wherein the base member and the elastic member are both made of resin materials, and the molding shrinkage rate of the resin material constituting the base member is smaller than the molding shrinkage rate of the resin material constituting the elastic member.

4. The seal member according to claim 1 , wherein the retention length is at least twice the width of the annular groove.

5. 5. A sealing member as described in any one of claims 1 to 4, wherein in a cross section of the base member taken along a plane that includes a straight line passing through a point along the annular groove and extending in the width direction of the annular groove at the point and is parallel to the depth direction of the base member, an angle formed by a pair of side surfaces of the annular groove is 20° or less.

6. The seal member according to claim 1 , wherein a through hole penetrating the base member is provided at a bottom of the annular groove in the base member.

7. A method for producing the seal member according to any one of claims 1 to 6, comprising the steps of: A method for manufacturing a seal member, comprising the steps of integrally assembling the elastic member and the base member in a mold by injection molding.

8. The method for manufacturing a sealing member described in claim 7, wherein the mold used to mold the elastic member is provided with a resin inlet for flowing resin from a gate to the annular abutment portion, and a resin inlet path leading from the resin inlet to the protrusion tip portion of the annular abutment portion.

9. The method for manufacturing a sealing member according to claim 8 , wherein an angle formed by a plane spanned by the tip of the protrusion and a direction in which the resin introduction path extends is smaller than an angle formed by the plane and an outer surface of the annular abutment portion at the tip of the protrusion.

10. The method for manufacturing a sealing member according to claim 9 , wherein an angle formed by a direction in which the resin introduction path extends and the plane is 30° or less.

11. a liquid storage chamber that stores a liquid and has at least a portion of an outer wall formed of a flexible film; an opening communicating with the liquid storage chamber; a pressure plate that is displaced in response to the displacement of the flexible film; a first biasing member that biases the pressing plate in a direction that expands the liquid storage chamber; The seal member according to any one of claims 1 to 6, having a sealing member arranged so that the distance between the elastic member of the sealing member and the opening changes in response to the displacement of the pressure plate, thereby changing the flow resistance to the liquid flowing through the opening, and the pressure of the liquid in the liquid storage chamber is adjusted.

12. a second biasing member that biases the seal member in a direction to close the opening by the elastic member; The pressure adjustment mechanism according to claim 11, which is a back pressure type pressure adjustment mechanism in which, when the pressure plate is displaced in a direction expanding the liquid storage chamber, the elastic member moves away from the opening, thereby reducing flow resistance to liquid flowing out of the liquid storage chamber through the opening.

13. In the seal member, the base member is formed in a lever shape and has a shaft so as to be rotatable about the shaft, the elastic member is provided at one end of the base member as viewed from the shaft, and the other end of the base member abuts against the pressing plate, The pressure adjustment mechanism according to claim 12 , wherein the distance between the elastic member and the opening changes due to rotation about the axis.

14. a second biasing member that biases the seal member in a direction to close the opening by the elastic member; The pressure adjustment mechanism of claim 11, which is a pressure reduction type pressure adjustment mechanism in which, when the pressure plate is displaced in a direction expanding the liquid storage chamber, the elastic member approaches the opening, thereby increasing the flow resistance to liquid flowing into the liquid storage chamber through the opening.

15. a plurality of recording element substrates each including a discharge port, a recording element that generates energy for discharging liquid from the discharge port, and a pressure chamber that includes the recording element therein; A pair of common flow paths communicating with the plurality of recording element substrates; a plurality of individual flow paths that connect one common flow path and the other common flow path of the pair of common flow paths and communicate with the plurality of pressure chambers, respectively; a pair of pressure adjustment mechanisms according to any one of claims 11 to 14, each of which is connected to an upstream side or a downstream side of the pair of common flow paths and set to pressures different from each other; A liquid ejection head comprising:

16. A liquid container for storing liquid; The liquid ejection head according to claim 15, a circulation mechanism that circulates liquid through a circulation path including the pair of common flow paths; A liquid ejection device comprising:

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