Liquid ejection device, print head, and method for manufacturing print head

Abstract

To provide a liquid discharge device which can inhibit liquid leakage and liquid dripping of a print head and inhibit increase in costs, and provide the print head and a manufacturing method of the print head.SOLUTION: A liquid discharge device includes a print head which has a storage part capable of storing a liquid and a pressure suppression member 180, joined to the storage part to suppress internal pressure change in the storage part, and which discharges the liquid stored in the storage part. A liquid seal material 185 for sealing a gap between the ink storage part 160 and the pressure suppression member is applied to the liquid discharge device.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a liquid ejection device that ejects liquid stored in a storage unit from a head unit, a print head, and a method for manufacturing a print head.

Background Art

[0002] A liquid ejection device that ejects liquid from a discharge port to perform recording on a recording medium such as paper has a storage unit that stores the liquid to be ejected. In the storage unit, the internal pressure changes according to the environment in which it is used (for example, the liquid ejection state from the discharge port). Therefore, by providing a pressure suppression member made of an elastic body in the storage unit, the pressure change in the storage unit may be suppressed. If there is a gap in the attachment portion between the storage unit and the pressure suppression member, the inside of the storage unit will not be sealed, so liquid leakage from the gap and liquid dripping from the discharge port of the print head may occur.

[0003] By the way, Patent Document 1 discloses that by sealing the entire gap area at the boundary between the spherical coating body and the tip edge of the chip with a non-drying liquid, the coating liquid inside the chip will not solidify even if left for a long time, and a passage for the coating liquid is ensured.

[0004] By applying the technology of Patent Document 1 to the liquid storage unit of the liquid ejection device, it may be possible to suppress liquid leakage and liquid dripping from the print head.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, if the technology of Patent Document 1 is applied to the liquid storage part of the liquid ejection device and the entire mounting surface of the pressure suppression member is sealed with a sealing member, the amount of the sealing member used will increase, and it may become difficult to seal with a simple configuration.

[0007] Therefore, the present invention provides a liquid ejection device, a print head, and a method for manufacturing a print head that can suppress liquid leakage and liquid dripping from the print head and can seal with a simple configuration.

Means for Solving the Problems

[0008] Therefore, the liquid ejection device of the present invention has a storage part capable of storing liquid, and a pressure suppression member joined to the storage part for suppressing a change in the internal pressure of the storage part, and is a liquid ejection device provided with a print head for ejecting the liquid stored in the storage part, wherein the storage part , front includes an inner wall surface of the storage part, a back surface of the top surface, an inner surface of a hole provided in the top surface, and a groove continuously provided on the top surface. A liquid sealing material for sealing between the storage part and the pressure suppression member exists therebetween, and the liquid sealing material is the liquid stored in the storage part.

Effects of the Invention

[0009] According to the present invention, it is possible to provide a liquid ejection device, a print head, and a method for manufacturing a print head that can suppress liquid leakage and liquid dripping from the print head and can suppress an increase in cost.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Mode for Carrying Out the Invention

[0011] (First Embodiment) Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.

[0012] FIG. 1 is a perspective view showing a main part of a liquid ejection device 1 to which the present invention is applicable. The liquid ejection device 1 performs printing on the medium 6 by alternately moving the print head 100 in the main scanning direction and the medium 6 in the sub-scanning direction, and ejecting a liquid (hereinafter also referred to as ink) from the print head 100 onto the medium 6.

[0013] The liquid ejection device 1 includes a carriage 2 on which the print head 100 is mounted and reciprocates, a conveyance roller 3 for conveying the medium 6, an ink tank 200 for storing ink, and a tube 4 connecting the ink tank 200 and the print head 100. Further, the liquid ejection device 1 includes a first shaft 8 and a second shaft 9 for guiding the moving carriage 2, and a cap unit 7 for capping the print head 100. When not printing, the print head 100 waits in a state where the nozzle portion of the print head 100 is sealed with a cap provided in the cap unit 7 at the position of the cap unit 7.

[0014] FIG. 2 is a perspective view showing the print head 100. The print head 100 includes a first recording element substrate 110 (mainly for black) and a second recording element substrate 111 (mainly for color) that discharge ink for printing. The support member 120 that supports each recording element substrate is fixed to the head portion 150 and is connected to the electrical wiring tape 130 and the electrical connection portion 140 to send an electrical signal for discharging to each recording element substrate. Each recording element substrate receives an electrical signal via the electrical connection member 140.

[0015] FIG. 3 is a view showing the print head 100. The print head 100 includes an ink storage portion 160 capable of storing ink therein. The head portion 150 of the print head 100 is a member for fixing the print head 100 to the liquid ejection device 1, and includes a recording element substrate 110 (111) for ejecting ink, an electrical wiring tape 130, an electrical connection member 140, and a filter 155. On the filter 155, the head portion 150 and the ink storage portion 160 are hermetically joined by being fixed with a seal member 170 interposed therebetween.

[0016] Since the pressure inside the ink storage portion 160 changes due to environmental factors and the influence of rocking caused by carriage movement during printing, a pressure suppression member 180 for suppressing internal pressure changes is provided on the upper portion of the ink storage portion 160. The pressure suppression member 180 is made of an elastic body having a space inside, and the ink storage portion 160 and the pressure suppression member 180 are hermetically joined at the seal surface 181 by pressing and fixing the pressure suppression member 180 against the ink storage portion 160 with a pressing member 190.

[0017] The print head 100 undergoes a leak inspection after assembly, but it may be judged NG in the inspection. Possible causes include dust being trapped between the ink storage unit 160 and the pressure suppression member 180 during the assembly process, or the pressure suppression member 180 being deformed. Or it is also possible that the seal surface 181 is partially damaged. When dust is trapped, the pressure suppression member 180 is deformed, or the seal surface 181 is partially damaged, a gap is generated at the joint between the ink storage unit 160 and the pressure suppression member 180, and air flows in through the gap, resulting in the inability to be sealed. Therefore, in this embodiment, a liquid sealant is used to seal the gap between the ink storage unit 160 and the pressure suppression member 180.

[0018] FIG. 4 is an enlarged view showing the joint between the ink storage unit 160 and the pressure suppression member 180. In this embodiment, with the ink storage unit 160 and the pressure suppression member 180 joined, the liquid sealant 185 is applied along the outer edge side end of the pressure suppression member 180. By applying the liquid sealant 185 in this way to seal the gap, even if dust is trapped at the joint, the pressure suppression member 180 is deformed, or the seal surface 181 is partially damaged and a gap is generated, the inside of the ink storage unit 160 can be kept in a sealed state.

[0019] It is conceivable to apply the liquid sealant 185 to the entire seal surface 181, but if the liquid sealant 185 is applied to the entire seal surface 181, the application amount will increase, resulting in a cost increase. Also, it is conceivable that it may flow out inside the pressure suppression member 180 or flow into the communication port of the ink storage unit 160. Therefore, after joining the pressure suppression member 180, it is preferable to apply the liquid sealant 185 along the outer edge end of the joint.

[0020] Figs. 5(a) and 5(b) show the experimental content for verifying the effects of the present invention and the results thereof. A wire 183 with a diameter of 40 / 25 / 15 μm was sandwiched between the ink storage unit 160 and the pressure suppression member 180, and the gap 182 generated by the wire 183 was measured. Further, with the gap 182 generated by the wire 183, the presence or absence of liquid dripping from the print head 100 was confirmed in a state without applying a liquid sealing material and in a state where a liquid sealing material 185 was applied.

[0021] The gap 182 generated when the wire 183 with a diameter of 40 μm was sandwiched was 15 μm, and liquid dripping occurred within one day in the dry state without applying a liquid sealing material. In contrast, when the liquid sealing material 185 was applied, no liquid dripping occurred from the print head 100 even after long-term storage.

[0022] The gap 182 generated when the wire 183 with a diameter of 25 μm was sandwiched was 9 μm, and liquid dripping occurred within one day in the dry state without applying a liquid.

[0023] The gap 182 generated when the wire 183 with a diameter of 15 μm was sandwiched was 6 μm, and no liquid dripping occurred from the print head 100 even after long-term storage in the dry state without applying a liquid sealing material.

[0024] From the above results, it was considered that by applying the liquid sealing material 185 along the outer edge side end of the pressure suppression member 180, even if the gap 182 is generated, it is sealed by the liquid sealing material 185, so that no liquid dripping occurs from the print head 100.

[0025] Thus, the liquid sealing material 185 is required to be able to seal the assumed gap (6 to 15 μm) and have physical properties (such as viscosity) optimal for sealing. In this embodiment, the liquid sealing material 185 uses a non-volatile, non-curing, and highly viscous material. Furthermore, it is more preferable to use the liquid sealing material 185 containing at least one of the materials included in the ink used in the liquid ejection device 1. Even more preferably, all the materials included in the liquid sealing material 185 are included in the ink. This is because even if the liquid sealing material 185 comes into contact with the ink and the components in the liquid sealing material 185 flow into the ink, if the components are those used in the ink, the influence on the quality of the ink can be suppressed. In this embodiment, general glycerin (viscosity: 1412 mPa·s (20°C)) or acetylenol (Kawaken Fine Chemicals Acetylenol E100) is used as the liquid sealing material 185.

[0026] FIG. 6(a) is a schematic diagram when dust (foreign matter) is sandwiched between the sealing surfaces 181, and FIG. 6(b) is a cross-sectional view taken along VIb-VIb of FIG. 6(a) with the liquid sealing material 185 omitted. When dust (foreign matter) is sandwiched between the sealing surfaces 181, the pressure suppression member 180, which is an elastic member, deforms, and a gap 182 is formed in a part of the sealing surface 181. The liquid sealing material 185 flows into the generated gap 182 by capillary action and seals the gap 182. By the liquid sealing material 185 sealing the gap 182, the inside of the pressure suppression member 180 and the ink storage portion 160 is in a sealed state.

[0027] In this embodiment, the liquid sealing material 185 is applied along the outer edge side end of the pressure suppression member 180. However, when a gap is formed between the ink storage portion 160 and the pressure suppression member 180, it is sufficient if the liquid sealing material 185 can flow into the gap. That is, it is sufficient if the liquid sealing material 185 is applied to the outer edge of the joint surface between the ink storage portion 160 and the pressure suppression member 180.

[0028] Thus, a liquid sealing material is applied along the outer edge of the joint surface between the ink storage unit 160 and the pressure suppressing member 180. As a result, it is possible to provide a liquid ejection device, a print head, and a method for manufacturing a print head that can suppress leakage of liquid and dripping of liquid from the head unit, and can also suppress cost increase.

[0029] (Second Embodiment) Hereinafter, a second embodiment of the present invention will be described with reference to the drawings. Since the basic configuration of this embodiment is the same as that of the first embodiment, the characteristic configuration will be described below.

[0030] FIG. 7 is an enlarged view showing the joint portion between the ink storage unit 160 and the pressure suppressing member 180 of this embodiment. At the joint portion between the ink storage unit 160 and the pressure suppressing member 180 of this embodiment, a convex portion 191 protruding toward the pressure suppressing member 180 is provided, and the surface of the convex portion 191 serves as the joint surface. By providing the convex portion 191 on the ink storage unit 160 in this way, a gap 182 is formed between the pressure suppressing member 180 and the ink storage unit 160. The liquid sealing material 185 flows into the gap 182 between the pressure suppressing member 180 and the ink storage unit 160, but the region where it flows in is from the outer edge measurement end portion of the pressure suppressing member 180 to the convex portion 191, and it does not flow into the inside from the convex portion 191. Therefore, according to this embodiment, the amount of the liquid sealing material 185 flowing into the gap can be controlled. In this way, by sealing the gap 182 between the pressure suppressing member 180 and the ink storage unit 160 with the liquid sealing material 185, the inside of the pressure suppressing member 180 and the ink storage unit 160 is in a sealed state.

[0031] (Third Embodiment) Hereinafter, a third embodiment of the present invention will be described with reference to the drawings. Since the basic configuration of this embodiment is the same as that of the first embodiment, the characteristic configuration will be described below. This embodiment also includes the convex portion 191, similar to the second embodiment.

[0032] FIG. 8(a) is a diagram showing the groove 302 provided in the print head 300 in the present embodiment, and FIG. 8(b) is a diagram showing the groove 302 on the top surface 306 of the ink storage unit 301. The ink storage unit 301 provided in the print head 300 includes a groove 302 that extends in the arrow Z direction along the inner wall surfaces 303 on both sides in the arrow X direction. The groove 302 extends in the arrow Z direction along the inner wall surface 303 from the surface sealed by the seal member 170 of the ink storage unit 301 and reaches the back surface 304 of the top surface. The groove 302 further extends along the back surface 304 of the top surface toward the central portion of the ink storage unit 301, and further extends in the arrow Z direction along the inner surface of the hole portion 305 provided in the central portion of the ink storage unit 301 to reach the top surface 306 of the ink storage unit 301. The groove 302 that has reached the top surface 306 further extends along the top surface 306 from the center of the ink storage unit 301 toward the outside to the convex portion 191.

[0033] In this way, by providing the continuous groove 302 from the inner wall surface 303 to the top surface 306 in the ink storage unit 301, the ink 210 in the ink storage unit 301 is carried along the groove 302 to the convex portion 191 by capillary action. The ink carried to the convex portion 191 is evenly distributed in a ring shape as shown in FIG. 8(b) along the convex portion 191 by the capillary action generated between the convex portion 191 and the pressure suppression member 180. The annular ink 210 forms a liquid bridge in the gap formed by the pressure suppression member 180, the convex portion 191, and the top surface 306, and a meniscus is formed. In this way, the inside of the ink storage unit 301 can be sealed by the meniscus formed between the pressure suppression member 180 and the top surface 306 along the convex portion 191.

[0034] FIG. 9 is a diagram showing the ink storage unit 301 during the recording operation. If there are obstacles such as dust adhesion or molding defects inside the groove 302, it is conceivable that the ink 210 will stop in the middle of the groove 302. However, as shown in FIG. 9, the grooves 302 are formed on the inner walls on both sides of the ink storage unit 301 in the main scanning direction (predetermined direction) in which the print head 100 moves. By forming the grooves 302 in this way, the inertial force due to the reciprocating movement of the print head 100 acts on the ink 210, and the water surface of the ink 210 rises and falls, so that the ink 210 can overcome dust and molding defect locations and reach the convex portion 191 along the groove 302. If dust or molding defect locations are at the upper part of the ink storage unit 301, it is also conceivable that the ink 210 will not reach the dust or molding defect locations when the amount of ink 210 in the ink storage unit 301 is small. In that case, the ink 210 may be replenished.

[0035] Hereinafter, the amount by which the ink 210 crawls up along the groove 302 by capillary action will be described.

[0036] The height h at which a liquid crawls up in a vertical tube by capillary force is

[0037]

Equation

[0038] It can be expressed as. Here, T: Surface tension of the liquid ρ: Density of the liquid r: Inner diameter (radius) of the tube θ: Contact angle and in the embodiment, T: 0.030 or 0.036 [N / m] (hereinafter, calculate with T = 0.030 [N / m] which is more difficult to crawl up) ρ: 1000 [kg / m 3 r: r [m] θ: 30 [deg] Let it be.

[0039] Substituting these values into Equation (1),​

[0040] [Number]

[0041] Here, the equivalent radius re [m] of a groove with a side length of d [m] is

[0042] [Number]

[0043] Since the height from the bottom surface to the top surface 306 of the ink storage unit 301 in the embodiment is 19 [mm], substituting these values into Equation (2),

[0044] [Number]

[0045] [Number]

[0046] This is obtained. Therefore, if the groove has a thickness and depth of 0.4 [mm] or less, the ink 210 can be transported from the bottom surface to the top surface 306 of the ink storage unit 301.

[0047] Also, when the user fills the print head 100 with ink, the ink 210 is filled to about half the height of the ink storage unit 301. Therefore, the lower end of the groove 302 in the arrow Z direction (see FIG. 8) may be provided below half of the height from the bottom surface to the top surface 306 of the ink storage unit 301. Thus, in use, in Equation (2),

[0048] [Number]

[0049] is sufficient, and calculating this gives

[0050]

Number

[0051] It follows that, in use, a groove having a size of 0.8 [mm] square or less (groove width of 0.8 mm or less) is sufficient.

[0052] FIGS. 10 and 11 are diagrams showing modified examples of the present embodiment. FIG. 10(a) shows an example in which two ribs 307 continuous from the bottom of the ink storage section to the top surface 306 are provided. A configuration may be adopted in which two continuous ribs 307 are formed as shown in FIG. 10(a), and the capillary action of the ink 210 is utilized with the space between the two ribs 307 serving as a groove. FIG. 10(b) shows an example in which a groove 302 is provided on the top surface 306 and two continuous ribs 307 are provided on the other parts. Further, FIG. 10(c) shows a configuration in which two ribs 307 are provided up to the middle of the top surface 306 and a groove 302 is provided from the middle onward. A configuration in which the two ribs 307 are switched to the groove 302 in the middle of the top surface 306 may be adopted.

[0053] Furthermore, as shown in FIG. 11, a configuration may be adopted in which a groove 302 is provided on at least one of the inner walls of the ink storage section 301 in the direction of arrow X. Grooves may also be provided in directions other than the direction of arrow X on the inner wall of the ink storage section 301. Further, the configuration shown in FIG. 11 may be combined with the configuration shown in FIG. 10 as appropriate.

Explanation of Signs

[0054] 1 Liquid ejection device 2 Carriage 100 Print head 150 Head section 160 Ink storage section 180 Pressure suppression member 182 Gap 185 Liquid sealing material 210 Ink 302 Groove 306 Top surface 307 Rib

Claims

1. A storage section capable of storing a liquid, and a pressure suppression member joined to the storage section for suppressing changes in the internal pressure of the storage section, and a liquid discharge device including a print head for discharging the liquid stored in the storage section, wherein the storage section includes an inner wall surface of the storage section, a back surface of the top surface, an inner surface of a hole provided in the top surface, and a groove provided continuously with the top surface, a liquid sealing material for sealing between the storage section and the pressure suppression member exists between the storage section and the pressure suppression member, and the liquid sealing material is the liquid stored in the storage section. The liquid discharge device is characterized by this.

2. The liquid discharge device according to claim 1, wherein the liquid sealing material is capable of sealing a gap of 6 to 15 μm.

3. The liquid discharge device according to claim 1 or 2, wherein the pressure suppression member is pressed against the storage section by a pressing member.

4. The liquid discharge device according to any one of claims 1 to 3, wherein the pressure suppression member is made of an elastic body.

5. The liquid discharge device according to claim 4, wherein the pressure suppression member joined to the storage section includes a space communicating with the inside of the storage section.

6. The liquid discharge device according to any one of claims 1 to 5, wherein the storage section includes a convex portion protruding toward the pressure suppression member, and the convex portion and the pressure suppression member are joined.

7. The liquid discharge device according to claim 1, wherein the groove is formed by an inner wall surface of the storage section, a back surface of the top surface, an inner surface of a hole provided in the top surface, and two ribs provided continuously with the top surface.

8. The storage section reciprocates in a predetermined direction together with the print head, and the liquid discharge device according to claim 7, wherein the groove is provided on at least one inner wall of the storage section in the predetermined direction.

9. The liquid discharge device according to claim 8, wherein the groove is provided on both inner walls of the storage section in the predetermined direction.

10. The liquid discharge device according to any one of claims 1 to 9, wherein the width of the groove is 0.8 mm or less.

11. The liquid discharge device according to any one of claims 1 to 10, wherein the groove is provided from below half of the height from the bottom surface to the top surface of the ink storage section.

12. A storage section capable of storing a liquid, A pressure suppression member that is joined to the storage part and suppresses changes in the internal pressure of the storage part, and a print head that discharges the liquid stored in the storage part, The storage part includes an inner wall surface of the storage part, a back surface of the top surface, an inner surface of a hole provided in the top surface, and a groove continuously provided on the top surface. A liquid sealant for sealing between the storage part and the pressure suppression member exists between them. The liquid sealant is the liquid stored in the storage part, and is a print head characterized by this.

13. The print head according to claim 12, wherein the storage part includes a convex part that protrudes toward the pressure suppression member, and the convex part and the pressure suppression member are joined.

14. A convex part is provided between the storage part and the seal surface of the pressure suppression member. The liquid discharge device according to claim 1, wherein the liquid sealant is provided between the top surface of the storage part inside the convex part and the seal surface of the pressure suppression member.

15. A convex part is provided between the storage part and the seal surface of the pressure suppression member. The print head according to claim 12, wherein the liquid sealant is provided between the top surface of the storage part inside the convex part and the seal surface of the pressure suppression member.

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