Liquid ejection head, liquid ejection device and their manufacturing methods

Abstract

To provide a liquid discharge head that can supply liquid from a liquid storage part to a liquid discharge part stably and excellently.SOLUTION: A liquid discharge head 1 comprises: a liquid discharge part 4 having a discharge port 11 for discharging liquid; a liquid storage part 5 whose one end opens; holding members 13 which is inserted into the liquid storage part 5 and can hold liquid; a liquid flow passage 16 which connects the liquid discharge part 4 to the liquid storage part 5; a filter 15 arranged at an end part at the liquid storage part 5 side of the liquid flow passage 16; and a lid member 14 fixed to an opening part of the liquid storage part 5. At a position corresponding to the filter 15 through the holding members 13, on a surface at the liquid storage part 5 side of the lid member 14 is provided a protruding part 24 for pressing on the surface which has the largest protrusion length protruding toward the liquid storage part 5 and which contacts the holding member 13.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a liquid ejection head, a liquid ejection device, and a method for manufacturing the same. [Background technology]

[0002] A liquid ejection head that ejects liquid such as ink has a liquid ejection section that ejects liquid, a liquid storage section that stores liquid to be supplied to the liquid ejection section, and a liquid flow path that communicates the liquid storage section and the liquid ejection section. In the configuration described in Patent Document 1, the liquid storage section is a hollow box with an open upper end, and a holding member that holds liquid is inserted inside, and a lid member is attached from above to close the opening. A filter is disposed at the end of the liquid flow path on the liquid storage section side, and the filter is in contact with the holding member. A rib that abuts against the holding member in the liquid storage section is provided on the surface of the lid member on the liquid storage section side. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-81084 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the configuration described in Patent Document 1, the ribs of the cover member press the holding member, so that the liquid is efficiently supplied from the holding member of the liquid storage unit to the liquid discharge unit. In particular, by sucking from the discharge port of the liquid discharge unit while the ribs of the cover member press the holding member, the liquid held by the holding member is smoothly supplied to the liquid discharge unit via the filter and the liquid flow path. However, when a liquid with high surface tension or high viscosity is used, there are cases where the liquid cannot be efficiently supplied to the liquid discharge unit even if the ribs of the cover member press the holding member and sucking from the discharge port are performed.

[0005] SUMMARY OF THE PRESENT DISCLOSURE In view of the above circumstances, an object of the present invention is to provide a liquid ejection head and a liquid ejection device capable of stably and satisfactorily supplying liquid from a liquid storage portion to a liquid ejection portion, as well as a method of manufacturing the same. [Means for solving the problem]

[0006] The liquid ejection head of the present invention is a liquid ejection head having a liquid ejection section having an ejection port for ejecting liquid, a liquid storage section, a holding member inserted inside the liquid storage section and capable of holding liquid, a liquid flow path connecting the liquid ejection section and the liquid storage section, a filter arranged at an end of the liquid flow path on the liquid storage section side, and a lid member fixed to the liquid storage section, wherein the lid member is provided with a pressing protrusion on the surface on the liquid storage section side at a position facing the filter via the holding member, which protrudes towards the liquid storage section and abuts against the holding member to press the holding member, the filter is fixed to a seat surface that defines an end of the liquid flow path on the liquid storage portion side and to a filter receiver that is located within a space surrounded by the seat surface, The liquid flow path is The liquid flow path is provided at a position facing the filter and adjacent to the filter receiver on both sides of the filter receiver. The liquid introduction groove is formed by cutting out a portion of the liquid introduction groove. Effect of the Invention

[0007] A liquid ejection head and a liquid ejection device capable of stably and satisfactorily supplying liquid from a liquid storage section to a liquid ejection section, and a method for manufacturing the same are provided. [Brief description of the drawings]

[0008] [Figure 1] 1 is a perspective view of a liquid ejection apparatus including a liquid ejection head of the present invention. [Diagram 2] 2 is a schematic cross-sectional view showing a liquid supply path of the liquid ejection device shown in FIG. [Diagram 3] 2 is an enlarged cross-sectional view showing a main part of a liquid ejection head of the liquid ejection device shown in FIG. [Figure 4] 4 is an exploded cross-sectional view showing the main parts of the liquid ejection head and the flow path connecting member shown in FIG. [Diagram 5] 5A is a perspective view of the liquid ejection head shown in FIG. 4 as viewed from above, and FIG. 5B is a perspective view of the cover member as viewed from below. [Figure 6] FIG. 5(a) is a cross-sectional view taken along line AA in FIG. [Figure 7] 1A is a plan view showing the liquid storage section without the holding member, FIG. 1B is an enlarged perspective view of part B in FIG. 1A, and FIG. 1C is an enlarged perspective view of part B without the filter. [Figure 8] 5(a) to 5(f) are cross-sectional views sequentially illustrating the steps of a method for manufacturing the liquid ejection head shown in FIG. [Figure 9] 9A is an enlarged cross-sectional view of the periphery of the filter of the liquid ejection head shown in FIG. 8, and (b) to (c) are enlarged cross-sectional views sequentially showing the flow of liquid in part C of (a). [Figure 10] 9(b) is an enlarged cross-sectional view of the periphery of the filter in a state where the filter is deformed before the lid member of the liquid ejection head shown in FIG. 9(a) is fixed. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. [Basic configuration of liquid ejection device] FIG. 1 is a perspective view showing the internal structure of a liquid ejection device 2 including a liquid ejection head 1 according to an embodiment of the present invention with the exterior removed. FIG. 2 is a cross-sectional view showing a liquid supply path including the liquid ejection head 1 of the liquid ejection device 2. FIG. 3 is an enlarged cross-sectional view showing a main part of the liquid ejection head 1. The liquid ejection device 2 is a serial scan type recording device, and has a carriage 3 that can reciprocate in the main scanning direction (X direction) along a guide shaft by a carriage motor and a driving force transmission mechanism such as a belt that transmits the driving force. The carriage 3 is mounted with a liquid ejection head 1 having a liquid ejection unit 4 and a liquid storage unit 5 that supplies liquid (ink) to the liquid ejection unit 4. One end of a flexible tube 8 is connected to a liquid storage container (liquid tank) 7 fixed inside the liquid ejection device body, and the other end of the tube 8 is connected to a flow path connection member 9 provided on the upper part of the carriage 3. The liquid storage unit 5 of the liquid ejection head 1 is connected to the flow path connection member 9. Therefore, when the liquid ejection head 1 is attached to the carriage 3 (when the liquid ejection head 1 is in use), the liquid ejection head 1 communicates with the liquid tank 7 via the flow path connecting member 9 and the tube 8.

[0010] In this embodiment, a recording medium 10 such as paper (see FIG. 3) onto which liquid is discharged from the liquid discharge head 1 to perform recording is transported in a sub-scanning direction (Y direction) perpendicular to the main scanning direction of the carriage 3 by a platen and transport rollers.

[0011] In this liquid ejection device 2, liquid is ejected from ejection ports 11 (see FIG. 3) of a liquid ejection unit 4 toward a recording area of ​​a recording medium positioned on a platen while a carriage 3 carrying a liquid ejection head 1 is moved in the main scanning direction. This liquid ejection operation and a transport operation that transports the recording medium 10 in the sub-scanning direction a distance corresponding to the recording range of one scan are repeated. In this way, liquid is sequentially ejected onto the recording medium 10 to record characters, images, patterns, etc. While recording is being performed by ejecting liquid, liquid contained in a liquid tank 7 is supplied to a liquid storage unit 5 of the liquid ejection head 1 through a tube 8.

[0012] [Liquid tank] The liquid tank 7 fixed to the liquid ejection device body has a liquid storage chamber 25 and a buffer chamber 26. The liquid storage chamber 25 is sealed except for a communication opening 27 that communicates with the buffer chamber 26. The liquid storage chamber 25 does not have a retaining member such as a fiber absorbent inside, and stores a large amount of liquid. A connecting pipe 28 is attached near the bottom of the liquid storage chamber 25 in the vertical direction, and the connecting pipe 28 is connected to a tube 8. The inside of the liquid storage chamber 25 is connected to a flow path connecting member 9 via the connecting pipe 28 and the tube 8. The buffer chamber 26 is provided with an outside air communication hole 31 that communicates with the outside air. The liquid storage chamber 25 and the buffer chamber 26 communicate with each other via the communication opening 27. Therefore, the liquid stored in the liquid storage chamber 25 of the liquid tank 7 is supplied to the liquid storage section 5 of the liquid ejection head 1 via the connecting pipe 28, the tube 8, and the flow path connecting member 9. When an increase in the environmental temperature or a decrease in the environmental pressure of the liquid tank 7 occurs, the liquid inside the liquid storage chamber 25 flows into the buffer chamber 26, thereby suppressing fluctuations in the temperature and pressure of the liquid storage chamber 25.

[0013] [Liquid ejection head] The liquid ejection head 1 has a liquid ejection section 4 and a liquid storage section 5. As shown enlarged and typically in FIG. 3, the liquid ejection section 4 is formed with a plurality of ejection ports 11, a plurality of pressure chambers 12 each communicating with the ejection ports 11, and an internal flow path 6 each communicating with the pressure chambers 12. An energy generating element (e.g., a heat generating element (electrothermal converter) 22) that generates energy for ejecting liquid is disposed in each pressure chamber 12 of the liquid ejection section 4. When the liquid ejection head 1 is mounted on the carriage 3 (when the liquid ejection head 1 is in use), the liquid ejection section 4 and the liquid storage section 5 are positioned vertically side by side. The ejection port 11 is provided at the bottom in the vertical direction when the liquid ejection head 1 is attached to the recording device body.

[0014] As shown in FIG. 4, the liquid storage section 5 is a hollow box-like structure with an open upper end (the upper end in the vertical direction when the liquid ejection head 1 is in use). A holding member (e.g., a fiber absorbent or a porous body) 13 capable of holding a certain amount of liquid is inserted inside the liquid storage section 5, and a cover member 14 is attached from above the opening to close the opening. The liquid storage section 5 and the liquid ejection section 4 are connected by a liquid flow path 16. The liquid flow path 16 extends vertically from above to below when the liquid ejection head 1 is in use. A filter 15 is disposed at the end of the liquid flow path 16 on the liquid storage section 5 side to prevent dust from entering the liquid ejection section 4, and the filter 15 is in contact with the holding member 13. The liquid storage section 5 is in communication with the liquid flow path 16, which leads to the ejection port 11 of the liquid ejection section 4, via the filter 15.

[0015] The liquid supplied to the liquid storage section 5 of the liquid ejection head 1 from the liquid tank 7 fixed to the liquid ejection device body through the tube 8 and the flow path connecting member 9 is held in the holding member 13. The liquid held in the holding member 13 passes through the filter 15, flows through the liquid flow path 16, and flows into the liquid ejection section 4. The liquid that flows into the liquid ejection section 4 reaches the pressure chamber 12 through the internal flow path 6. In this state, when an electric signal is supplied to the heating element 22 through wiring (not shown), the heating element 22 generates thermal energy, heating the liquid in the pressure chamber 12 and foaming due to film boiling. This foaming energy causes droplets to be ejected from the ejection port 11 to the outside. Note that a piezoelectric element or the like may be used as the energy generating element instead of the heating element 22.

[0016] [Liquid supply path] In the liquid supply path connecting the liquid tank 7 to the liquid discharge head 1 shown in FIG. 2, only the outlet 11 of the liquid discharge unit 4 of the liquid discharge head 1 and the communication opening 27 of the liquid tank 7 are in contact with the outside air. When the liquid discharge head 1 is attached to the liquid discharge device body, the liquid discharge unit 4 is located at a position higher than the water level of the liquid tank 7. Therefore, a negative pressure is generated inside the liquid discharge unit 4 due to the head difference between the position of the outlet 11 of the liquid discharge unit 4 and the position of the communication opening 27 of the liquid tank 7, and the liquid is held inside the liquid discharge unit 4 so that the liquid does not drop from the outlet 11 of the liquid discharge unit 4. It is possible to maintain a constant negative pressure inside the liquid discharge unit 4 regardless of the position of the liquid level inside the liquid storage chamber 25 of the liquid tank 7.

[0017] When liquid continues to be discharged from the discharge port 11 of the liquid discharge unit 4, the negative pressure in the liquid discharge head 1 increases. When the negative pressure inside the liquid discharge unit 4 becomes greater than the sum of the flow resistance of the liquid path from the liquid tank 7 to the liquid discharge head 1 and the meniscus force at the communication opening 27, outside air is supplied to the liquid storage chamber 25 from the communication opening 27. This causes liquid to be supplied from the liquid tank 7 to the liquid discharge head 1 via the tube 8. As a result, the negative pressure inside the liquid discharge head 1 is alleviated, returning to the state before liquid discharge, and the negative pressure inside the liquid discharge unit 4 is kept constant. This series of operations is repeated, and liquid continues to be supplied from the liquid tank 7 of the liquid discharge device 2 to the liquid storage unit 5 of the liquid discharge head 1.

[0018] [Connection between the liquid ejection head and the flow path connection member] 4 shows an exploded cross-sectional view of the liquid ejection head 1 and a flow path connecting member 9 connected to the liquid ejection head 1. The flow path connecting member 9 has a plurality of protrusions 17, 18 that protrude toward the liquid ejection head 1. The plurality of protrusions 17, 18 of the flow path connecting member 9 are all hollow pipe-shaped, and include a positioning protrusion 17 having a positioning opening 17a, and a liquid circulation protrusion 18 having a liquid circulation opening 18a. A hollow tube-shaped elastic member 19 is inserted into the liquid circulation opening 18a of the liquid circulation protrusion 18.

[0019] The cover member 14 of the liquid ejection head 1 to which the flow path connection member 9 is connected has a plurality of pin-shaped projections 20, 21 projecting in a direction toward the outside of the liquid storage unit 5 (toward the flow path connection member 9 to be connected). The plurality of projections 20, 21 of the cover member 14 include a positioning projection 20 and a liquid circulation projection 21. The positioning projection 20 fits into the positioning opening 17a of the positioning projection 17, and the flow path connection member 9 is accurately positioned with respect to the cover member 14. The liquid circulation projection 21 is inserted into a hollow portion of the elastic member 19 inside the liquid circulation opening 18a of the liquid circulation projection 18. Although not shown, liquid can flow through a gap between the inner peripheral surface of the elastic member 19 and the outer peripheral surface of the liquid circulation projection 21, and the liquid that passes through this gap is supplied to the inside of the liquid storage unit 5 and held by the holding member 13. That is, the liquid circulation opening 18a of the flow path connecting member 9 and the liquid circulation protrusion 21 of the cover member 14 cooperate to supply liquid to the liquid storage portion 5. Since the elastic member 19 is located outside the outer circumferential surface of the liquid circulation protrusion 21, the gap between the inner circumferential surface of the elastic member 19 and the outer circumferential surface of the liquid circulation protrusion 21 is sealed from the outside. In this way, the inside of the liquid ejection head 1 is in a sealed state except for the ejection port 11 of the liquid ejection portion 4 and the gap outside the outer circumferential surface of the liquid circulation protrusion 21 of the cover member 14. This allows the liquid to be smoothly supplied from the flow path connecting member 9 to the liquid storage portion 5 of the liquid ejection head 1.

[0020] [Cover parts] FIG. 5(a) is a perspective view of the liquid ejection head 1 of this embodiment as viewed from the top, and FIG. 5(b) is a perspective view of the liquid ejection head 1 as viewed from the bottom of the lid member 14. FIG. 6 is a cross-sectional view taken along the line AA in FIG. 5(a). FIG. 7(a) is a plan view of the liquid storage unit 5 without the holding member 13, FIG. 7(b) is an enlarged perspective view of part B in FIG. 7(a), and FIG. 7(c) is an enlarged perspective view of part B without the filter. The liquid ejection head 1 of this embodiment shown in FIG. 5 has three liquid storage units 5 in which three types (three colors) of liquid are respectively stored. A holding member 13 is inserted into each liquid storage unit 5. A lid member 14 is welded to the upper end surface of the housing 5a of the liquid storage unit 5 (the upper end surface in the vertical direction when the liquid ejection head 1 is mounted on the carriage 3). The lid member 14 is provided with three liquid circulation projections 21 corresponding to the three liquid storage units, respectively, and two positioning projections 20. Furthermore, the inner surface (surface facing the liquid storage unit 5) of the lid member 14 is provided with a rib 23 that abuts against the retaining member (fibrous absorbent) 13 inside the liquid storage unit 5. The rib 23 of the lid member 14 presses the retaining member 13 vertically downward in a state in which the lid member 14 is welded to the end surface of the housing 5a of the liquid storage unit 5.

[0021] Furthermore, a pressing protrusion 24 is provided on the outer periphery of the positioning projection 20, protruding from the inner surface of the cover member 14 toward the liquid storage section 5, i.e., toward the holding member 13 (vertically downward when the liquid ejection head 1 is in use). The pressing protrusion 24 is in contact with the holding member 13 like the rib 23, and has a greater protruding length toward the holding member 13 (vertically downward) than the rib 23. As an example, the difference in protruding length between the rib 23 and the pressing protrusion 24 is 2±0.2 mm. That is, the protruding length of the pressing protrusion 24 toward the liquid storage section 5 is greater than the protruding length of the rib 23 toward the liquid storage section 5 by 2±0.2 mm. Since the pressing protrusion 24 has a greater protruding length than the rib 23, it presses the holding member 13 more strongly. As an example, the dimension of the portion of the holding member 13 that abuts against the pressing protrusion 24 in the pressing direction (the vertical direction in FIG. 6) by the pressing protrusion 24 is smaller by 2±0.2 mm than the dimension of the other portion in the pressing direction.

[0022] As shown in FIG. 6 and FIG. 7(a), the liquid storage section 5 containing the holding member 13 is connected to the liquid flow path 16 and the liquid discharge section 4 via the filter 15. As shown in FIG. 7(b) and FIG. 7(c), the filter 15 is fixed to the seating surface 29 and the filter receiver 30, and is located at the end of the liquid flow path 16 on the liquid storage section 5 side. A part of the liquid flow path 16 facing the filter 15 is cut out to provide a liquid introduction groove 16a. The liquid storage section 5 and the liquid discharge section 4 are connected so that the liquid flows at the position where the filter 15 is disposed. When the holding member 13 and the filter 15 are in close contact with each other, the liquid is efficiently supplied from the holding member 13 to the liquid flow path 16 and the liquid discharge section 4 via the filter 15. Therefore, in order to reliably supply the liquid held in the holding member 13 to the liquid discharge section 4, it is required that the holding member 13 and the filter 15 are kept in pressure contact with each other. The rib 23 on the inner surface of the cover member 14 presses the holding member 13 toward the filter 15 (vertically downward), which contributes to the pressing of the holding member 13 and the filter 15. However, the position where the rib 23 presses the holding member 13 and the position where the holding member 13 presses against the filter 15 are offset in plan view, so the force transmission efficiency is not high. Therefore, in this embodiment, a pressing protrusion 24 with a protruding length greater than that of the rib 23 is provided on the inner surface of the cover member 14 at a position facing the filter 15 via the holding member 13, that is, at a position directly above the filter 15 in the use state. Therefore, among the contact points between the cover member 14 and the holding member 13, the holding member 13 is pressed downward, that is, toward the filter 15, with the strongest force at the position directly above the filter 15. As a result, the holding member 13 and the filter 15 are reliably brought into close contact with each other, and the liquid is more reliably and efficiently supplied from the holding member 13 to the liquid flow path 16 and the liquid discharge portion 4 via the filter 15. By providing the liquid flow path 16 with the liquid introduction groove 16a, the flow of liquid flowing from the filter 15 through the liquid flow path 16 into the liquid ejection part 4 becomes smoother.

[0023] [Method of manufacturing liquid ejection head] Next, a method for manufacturing a liquid ejection head and filling it with liquid in this embodiment will be described with reference to Figs. 8 to 10. As shown in Fig. 8(a), with the upper end of the liquid storage section 5 of the liquid ejection head open, a filter 15 is attached to the end of the liquid flow path 16 on the liquid storage section 5 side. As an example, the filter 15 is attached to the seating surface 29 and the filter receiver 30 (see Figs. 7(b) and 7(c)) by thermal welding using a constant heater. As shown in Fig. 8(b), a holding member (for example, a fiber absorber) 13 is inserted inside the liquid storage section 5. As shown in Fig. 8(c), a predetermined amount of liquid is poured into the liquid storage section 5. In Fig. 8, the dot pattern of the part of the holding member 13 that holds the liquid is made high density to distinguish it from the part that does not hold the liquid. As shown in Figs. 8(d) to 8(e), a cover member 14 is fixed to the end face of the opening at the upper end of the liquid storage section 5 (the upper end face of the housing 5a). As an example, the cover member 14 is attached by vibration welding. At this time, the liquid flows into the liquid flow path 16 and the liquid discharge unit 4 through the filter 15. As shown in Fig. 8(f), the surface of the liquid discharge unit 4 where the discharge port 11 is formed is capped with the cap 32, and suction force is applied by a pump (not shown), thereby causing the liquid flow path 16 and the liquid discharge unit 4 to be sufficiently filled with liquid.

[0024] The process of fixing the lid member 14 to the end face of the upper opening of the liquid storage section 5 as shown in Fig. 8(d) to Fig. 8(e) will be described in more detail. Fig. 9(a) is an enlarged cross-sectional view of the filter 15 and its surroundings immediately after the lid member 14 is welded. Fig. 9(b) to Fig. 9(c) are enlarged cross-sectional views sequentially showing the flow of liquid in part C of Fig. 9(a). As shown in Fig. 8(c), in a state in which liquid is injected into the liquid storage section 5 and at least a part of the holding member 13 holds the liquid, the lid member 14 is fixed to the end face of the upper opening of the liquid storage section 5 as shown in Fig. 8(d) to Fig. 8(e). The rib 23 and the pressing protrusion 24 on the inner surface of the lid member 14 come into contact with the holding member 13 and press the holding member 13 downward (towards the filter 15 and liquid flow path 16) to compress it. The liquid held in the holding member 13 permeates the filter 15 as shown by the arrows in Figs. 9(b) and 9(c). The liquid seeping out from the compressed holding member 13 is held in the filter 15, and as the amount of liquid seeping out from the holding member 13 increases, the filter 15 becomes saturated with liquid. After the filter 15 becomes saturated with liquid, if more liquid seeps out from the holding member 13, the liquid enters from the filter 15 into the liquid introduction groove 16a of the liquid flow path 16 below.

[0025] In particular, in this embodiment, the pressing protrusion 24 located directly above the filter 15 has a longer protrusion length than the other ribs 23, so the holding member 13 receives the largest pressing force at the position directly above the filter and is compressed the most. That is, the portion of the holding member 13 that abuts against the pressing protrusion 24 is compressed by the pressing protrusion 24 to a greater extent than other portions of the holding member 13. Since the holding member 13 is pressed toward the filter 15 in this manner, the filter 15 is pressed by the holding member 13 and comes into close contact with the end face of the liquid flow path 16. When the filter 15 comes into close contact with the end face of the liquid flow path 16, a capillary force is generated between the two, and the liquid is pulled toward the liquid flow path 16. As a result, the liquid present in a saturated state in the filter 15 breaks the meniscus and enters the liquid flow path 16. When the cover member 14 is fixed to the liquid storage portion 5, the liquid enters the liquid flow path 16 and the liquid discharge portion 4, improving the wettability of the insides thereof. This leads to the prevention of air inflow when a recovery operation is performed later.

[0026] If the pressing protrusion 24 having a longer protruding length than the other ribs 23 were not provided directly above the filter 15, the force of the rib 23 pressing the holding member 13 would not coincide with the position of the filter 15 in a plane. Therefore, there would be a loss of force, and the efficiency of the liquid entering the filter 15 and the liquid flow path 16 from the holding member 13 would be low. In contrast, in this embodiment, the pressing protrusion 24 having a longer protruding length than the other ribs 23 is provided directly above the filter 15, so that the force of the pressing protrusion 24 pressing the holding member 13 coincides with the position of the filter 15 in a plane. Therefore, the force of the pressing protrusion 24 pressing the holding member 13 acts directly to cause the liquid to enter the filter 15 and the liquid flow path 16 from the holding member 13, and the efficiency of the liquid entering the filter 15 and the liquid flow path 16 from the holding member 13 is very good.

[0027] In this embodiment, a pressing protrusion 24 is provided on the outer periphery of the positioning projection 20, which protrudes from the inner surface of the lid member 14 toward the holding member 13 side more than the other ribs 23. However, the shape is not limited to this. Whatever the shape of the protrusion, such as a rib-shaped member, it is important that the protrusion (pressing protrusion 24) that protrudes the longest toward the holding member 13 side among the parts of the inner surface of the lid member 14 that contact the holding member 13 is provided directly above the filter 15.

[0028] In this configuration having the pressing protrusion 24, even when liquid with high surface tension or high viscosity is first circulated from the holding member 13 of the liquid storage unit 5 to the liquid flow path 16 via the filter 15, it is possible to smoothly supply the liquid. As a result, when suction is performed from the discharge port 11 while pressing the holding member 13, it is possible to suppress the inflow of air into the liquid, and to make it difficult for air bubbles to be generated in the liquid supplied to the liquid discharge unit 4. The recovery process of the liquid discharge head can be performed well, and discharge defects can be suppressed. In addition, since air bubbles that need to be removed are unlikely to be generated in the liquid and there is a high possibility that a sufficient recovery process can be performed with one suction, there is little risk of an increase in the amount of liquid consumed due to multiple suctions.

[0029] As shown in FIG. 10, even if the filter 15 is warped and deformed, does not contact the inner peripheral end face of the liquid introduction groove 16a, and contacts the upper surface of the liquid storage section 5 at a position away from the liquid introduction groove 16a, the configuration of this embodiment is effective. From the state shown in FIG. 10, the pressing protrusion 24 with a long protruding length located directly above the filter 15 strongly presses the holding member 13, so that the holding member 13 and the filter 15 are closely attached to each other, and the filter 15 is further closely attached to the end face of the liquid introduction groove 16a. As a result, substantially similar to the example shown in FIGS. 8 and 9, the liquid can be efficiently introduced from the holding member 13 to the filter 15 and the liquid flow path 16. Such an effect is realized by providing the pressing protrusion 24 with the longest protruding length directly above the filter 15.

[0030] Due to variations in manufacturing errors in the housing 5a constituting the liquid storage unit 5, the height of the seating surface 29 on which the filter 15 is placed and the filter receiver 30 (see Figs. 7(b) and 7(c)) may vary, making it difficult for the filter 15 to contact the seating surface 29 near the liquid introduction groove 16a. Even in such a case, as described above, the pressing protrusion 24, which is located directly above the filter 15 and has a large protruding length, strongly presses the holding member 13, causing the holding member 13 to adhere closely to the filter 15, and the filter 15 to adhere closely to the end face near the liquid introduction groove 16a. As a result, the liquid can efficiently enter the filter 15 and the liquid flow path 16 from the holding member 13.

[0031] As described above, according to this embodiment, the liquid can efficiently enter the liquid ejection portion 4 from the holding member 13 through the filter 15 and the liquid flow path without being affected by warping, deformation, or molding errors of the filter 15. This improves the stability of the liquid supply to the liquid ejection portion 4.

[0032] In the liquid storage section 5 that stores a liquid having high surface tension or high viscosity among a plurality of types of liquid, it is particularly effective to provide the pressing protrusion 24, which has the longest protrusion length, directly above the filter 15. This makes it possible to use a liquid having high surface tension or high viscosity in the liquid ejection head 1 of this embodiment, expanding the options for liquids to be ejected.

[0033] Furthermore, according to this embodiment, liquid can be stably sucked from the discharge port 11 and bubbles are unlikely to flow in, so that discharge defects can be reduced and more liquid than necessary can be prevented from being consumed during recovery operations. [Explanation of symbols]

[0034] 1 Liquid ejection head 4 Liquid discharge part 5 Liquid storage section 11 Discharge port 13 Retaining member 14 Lid member 15 Filters 16 Liquid flow path 24 Pressing protrusion

Claims

1. A liquid ejection head comprising: a liquid ejection section having an ejection port for ejecting liquid; a liquid storage section; a holding member inserted inside the liquid storage section and capable of holding liquid; a liquid flow path connecting the liquid ejection section and the liquid storage section; a filter disposed at an end of the liquid flow path on the liquid storage section side; and a lid member fixed to the liquid storage section, the cover member includes a pressing protrusion on a surface of the liquid storage portion facing the filter with the holding member interposed therebetween, the pressing protrusion protruding toward the liquid storage portion and coming into contact with the holding member to press the holding member, the filter is fixed to a seat surface that defines an end of the liquid flow path on the liquid storage portion side and to a filter receiver that is located within a space surrounded by the seat surface, The liquid flow path includes liquid introduction grooves formed by cutting out a part of the liquid flow path at a position facing the filter and adjacent to the filter receiver on both sides of the filter receiver. A liquid ejection head comprising:

2. 2. The liquid ejection head according to claim 1, wherein the portion of the holding member that abuts against the pressing protrusion has a dimension in the pressing direction by the pressing protrusion that is smaller by 2±0.2 mm than the dimension of the other portion in the pressing direction.

3. 3. The liquid ejection head according to claim 1, wherein, when the liquid ejection head is in a state of use, the liquid ejection portion and the liquid storage portion are positioned vertically side by side, the liquid flow path extends vertically from above to below, the vertical upper end of the liquid storage portion is open, and the pressing protrusion protrudes vertically downward.

4. A liquid ejection head according to any one of claims 1 to 3, wherein the pressing protrusion and a rib are provided on the surface of the cover member facing the liquid storage portion, and the pressing protrusion has a longer protruding length toward the liquid storage portion than the rib.

5. 5. The liquid ejection head according to claim 4, wherein a length of said pressing protrusions protruding towards said liquid storage portion is greater than a length of said ribs protruding towards said liquid storage portion by 2.+-.0.2 mm.

6. The liquid ejection head according to claim 1 , wherein the holding member is a fibrous absorbent.

7. 7. A liquid ejection apparatus comprising: the liquid ejection head according to claim 1; a liquid tank; and a tube connecting the liquid ejection head and the liquid tank.

8. The tube further includes a flow path connecting member that connects the tube and the cover member. the flow path connecting member is provided with a liquid flow protrusion having a liquid flow opening, A hollow elastic member is inserted into the liquid flow opening, The liquid ejection device according to claim 7 , wherein the cover member is provided with a liquid circulation protrusion that is inserted into the elastic member and cooperates with the liquid circulation opening and the elastic member to supply liquid to the liquid storage section.

Images