JP2024071950A - Liquid discharge head, liquid discharge unit, device for discharging liquid, and method for manufacturing liquid discharge unit - Google Patents

Abstract

To provide a liquid ejection head enabling performing highly accurate alignment in the planar direction with respect to the head holding member while ensuring high parallelism.SOLUTION: A liquid ejection head 23 is held by a head holding member 21, and includes a protruding seat portion that protrudes from an opposing surface (a lower surface of a flange portion 60) that faces an abutted surface (upper surface) of the head holding member 21 and abuts against the abutted surface, and a peripheral edge of a seat portion of the protruding seat portion is chamfered. This ensures a high degree of parallelism between the head holding member 21 and the liquid ejection head 23, and improves accuracy of alignment in a planar direction of the liquid ejection head with respect to the head holding member.SELECTED DRAWING: Figure 6

Description

The present invention relates to a liquid ejection head, a liquid ejection unit, a device for ejecting liquid, and a method for manufacturing a liquid ejection unit.

Conventionally, liquid ejection heads held by a head holding member are known. For example, Patent Document 1 discloses a droplet ejection head (liquid ejection head) that is assembled into an assembly hole provided in a metal base (head holding member). This droplet ejection head is precisely aligned and fixed to a predetermined position on the metal base so that ink droplets (liquid) ejected from the droplet ejection head land at the target landing position.

Conventional liquid ejection heads sometimes could not be precisely aligned with the head holding member.

In order to solve the above-mentioned problems, the present invention provides a liquid ejection head held by a head holding member, which has a protruding seat portion that protrudes from an opposing surface of the head holding member that faces the contact surface and contacts the contact surface, and the peripheral edge of the seat portion of the protruding seat portion is chamfered.

The present invention provides a liquid ejection head that can be aligned with the head holding member in the planar direction with high precision while maintaining high parallelism.

FIG. 2 is an enlarged cross-sectional view of a main part of the liquid ejection head according to the embodiment, taken along a direction between channels. FIG. 2 is a perspective view showing the appearance of a liquid ejection unit in which the liquid ejection head is held by a metal base. FIG. 2 is an exploded perspective view showing the liquid ejection unit disassembled into a metal base, a liquid ejection head, and outer components. FIG. FIG. 4 is an explanatory diagram showing an example in which the liquid ejection unit is attached to an image forming apparatus main body. 1A is an explanatory diagram for explaining alignment in a planar direction of a liquid ejection head held by a metal base, and FIG. 1B is an explanatory diagram for explaining parallelism of the liquid ejection head held by the metal base. FIG. 2 is a perspective view showing a main part of an assembly device for the liquid ejection unit. FIG. 2 is a perspective view showing an overall configuration of an assembly device for the liquid ejection unit. 13 is an explanatory diagram of a case where the flatness and parallelism of the lower surface of the flange of the liquid ejection head held by the metal base is low. 1A is a plan view showing a comparative example in which a protruding seat portion is provided on the lower surface of a flange portion of a liquid ejection head, and FIG. 1A is a plan view showing an example of a protruding seat portion according to an embodiment, and FIG. 10A is a plan view showing another example of the protruding seat portion in the embodiment, and FIG. 13A is a plan view showing still another example of the protruding seat portion in the embodiment, and FIG. FIG. 1 is an explanatory diagram illustrating an example of a printing apparatus according to an embodiment.

Hereinafter, as an example of a liquid ejection head according to an embodiment of the present invention, an example in which it is used in an inkjet recording apparatus as an apparatus for ejecting liquid, which is an image forming apparatus using a liquid ejection recording method, will be described.
The liquid ejected from the liquid ejection head is not limited to so-called ink, but may be any liquid that becomes liquid when ejected, including, for example, DNA samples, resists, pattern materials, etc.

FIG. 1 is an enlarged cross-sectional view of a main part of a liquid ejection head according to this embodiment, taken along a direction between channels.
1, the ejection section of the liquid ejection head 23 includes a frame member 1, a vibration plate 2, a flow path plate 3, a nozzle plate 4, a laminated piezoelectric element 5, and a PZT base 6. The frame member 1 is a member in which carvings are formed to form an ink supply port 16 and a common liquid chamber 8. The vibration plate 2 has a convex portion 13, a diaphragm portion 14, and an ink inlet 15. The flow path plate 3 is formed with carvings to form a pressurized liquid chamber 9 and a fluid resistance portion 10, and a communication hole 12 communicating with a nozzle hole 11. The nozzle plate 4 is formed with a nozzle hole 11. The laminated piezoelectric element 5 is bonded to the vibration plate 2 via an adhesive layer. The PZT base 6 fixes the laminated piezoelectric element 5.

The laminated piezoelectric element 5 is divided into comb teeth by half-cut dicing, and each part is used as a driving part and a support part (non-driving part). The length of the outer side of the external electrode is limited by notches and other processing so that it can be divided by half-cut dicing, and these become multiple individual electrodes. The other side is not divided by dicing and is conductive, becoming a common electrode. The FPC 7 is soldered to the individual electrodes of the driving part. In addition, the common electrode is attached to the end of the laminated piezoelectric element 5 by providing an electrode layer, which is then twisted around and joined to the ground electrode 5-1 of the FPC 7. A driver IC is mounted on the FPC 7, which controls the application of drive voltage to the driving part.

The diaphragm 2 is made of two layers of Ni plating film formed by electroforming, including a thin diaphragm section 14, an island-shaped protrusion 13, a thick film section including a beam that is joined to the support section, and an opening that serves as the ink inlet 15. The island-shaped protrusion 13 is joined to the laminated piezoelectric element 5 that serves as the drive section, which is formed in the center of the diaphragm section 14. The island-shaped protrusion 13 of the diaphragm 2 and the movable section 5-2 of the laminated piezoelectric element 5, and the diaphragm 2 and frame member 1 are bonded by patterning an adhesive layer that contains a gap material.

The flow path plate 3 is made of a silicon single crystal substrate, and is patterned by etching to form the engraved portions that will become the pressurized liquid chamber 9 and the fluid resistance portion 10, as well as the through-holes that will become the communication holes 12 at positions corresponding to the nozzle holes 11. Specifically, they can be formed by anisotropic etching using an alkaline etching solution such as an aqueous potassium hydroxide solution (KOH). The portions that remain after etching become the partition walls of the pressurized liquid chamber 9. Additionally, in this head, there are portions where the etching width is narrowed, and these serve as the fluid resistance portions 10.

The nozzle plate 4 is made of a metal material, such as a Ni plating film formed by electroforming, and has many nozzle holes 11, which are minute ejection ports for ejecting ink droplets (liquid). The internal shape (inner shape) of the nozzle holes 11 is formed in a horn shape, but it may also be in a roughly cylindrical or truncated cone shape. The diameter of the nozzle holes 11 is, for example, about 15 to 30 μm on the ink droplet outlet side. The nozzle pitch of each row is, for example, 150 or 300 dpi.

The ink ejection surface (nozzle surface side) of the nozzle plate 4 is provided with a liquid-repellent treatment layer that has been subjected to a liquid-repellent surface treatment. A water-repellent treatment film is provided that is selected according to the ink properties, such as PTFE-Ni eutectoid plating, electrochemical coating of fluororesin, deposition coating of volatile fluororesin (such as pitch fluoride), or baking after solvent application of silicone resin or fluororesin.

The frame member 1, which forms the ink supply port 16 and the engraving that will become the common liquid chamber 8, is made by resin molding. The periphery of the ink inlet 15 of the vibration plate 2 is sealed and joined with an adhesive applied to the frame member 1 without any gaps. The frame member 1 is formed with a common liquid chamber 8 that supplies ink to each pressurized liquid chamber 9, and ink liquid is supplied from the common liquid chamber 8 to the pressurized liquid chamber 9 via the ink inlet 15 formed in the vibration plate 2, the flow path formed upstream of the fluid resistance section 10, and the fluid resistance section 10. The frame member 1 also has an ink supply port 16 for supplying ink liquid from the outside to the common liquid chamber 8. The common liquid chamber 8 is formed in a rectangular shape in plan view in the direction in which the pressurized liquid chambers 9 are arranged (the direction in which the nozzles are arranged).

In the liquid ejection head 23 configured in this way, a driving waveform (a pulse voltage of 10 to 50 [V]) is applied to the driving section in response to a recording signal. A displacement in the stacking direction occurs in the driving section, and the pressurized liquid chamber 9 is pressurized via the vibration plate 2, increasing the pressure, and ink droplets are ejected from the nozzle hole 11. After that, as the ink droplet ejection ends, the ink pressure in the pressurized liquid chamber 9 decreases, and negative pressure is generated in the pressurized liquid chamber 9 due to the inertia of the ink flow and the discharge process of the drive pulse, and the ink moves to the ink filling process. At this time, the ink supplied from the ink tank flows into the common liquid chamber 8, passes from the common liquid chamber 8 through the ink inlet 15, passes through the fluid resistance section 10, and is filled in the pressurized liquid chamber 9. While the fluid resistance section 10 is effective in attenuating the residual pressure vibration after ejection, it also acts as a resistance to refilling (refilling) due to surface tension. By appropriately selecting the fluid resistance section 10, the balance between the attenuation of the residual pressure and the refill time can be achieved, and the time (driving period) until the transition to the next ink droplet ejection operation can be shortened.

In this embodiment, it is preferable that at least a part of the liquid chamber, fluid resistance, vibration plate, and nozzle member of the ink ejection section of the liquid ejection head 23 is made of a material containing at least one of silicon and nickel. Also, in this embodiment, a laminated piezoelectric element is used as the drive actuator, but a thin film piezoelectric or the like may also be used as the actuator.

FIG. 2 is a perspective view showing the appearance of a liquid ejection unit 20 in which a liquid ejection head 23 according to this embodiment is held by a metal base 21 serving as a head holding member.
FIG. 3 is an exploded perspective view showing the liquid discharge unit 20 of this embodiment disassembled into a metal base 21, a liquid discharge head 23, and an outer part 22. As shown in FIG.
Electrical components and the like are disposed inside the external component 22 .

Inkjet recording devices are required to have longer recording areas and higher nozzle density due to demands for higher speed and higher definition. However, if one liquid ejection head is used to achieve longer recording areas and higher nozzle density, it is difficult to manufacture and the cost increases significantly. In contrast, costs can be reduced by connecting multiple relatively small and easy-to-manufacture liquid ejection heads 23 to form a so-called integrated liquid ejection unit 20. Typical examples of such liquid ejection units 20 include those in which the liquid ejection heads 23 are staggered or connected in the nozzle row direction. The liquid ejection unit 20 of this embodiment is configured such that multiple liquid ejection heads 23 are assembled in a staggered manner to a metal base 21 serving as a head holding member.

FIG. 4 is a plan view of the metal base 21 according to the present embodiment.
The metal base 21 is provided with a plurality of assembly holes 21a for assembling a plurality of liquid ejection heads 23. The liquid ejection heads 23 are positioned (aligned) and fixed (bonded) to the metal base 21 using an assembly device described later.

When the metal base 21 is set in the assembly device, the liquid ejection head 23 is inserted into each mounting hole 21a of the metal base 21 in a state where the position can be adjusted slightly via the frame member 1, and temporarily attached. Specifically, as shown in FIG. 3, the frame member 1 has a portion (hereinafter referred to as "flange portion 60") that protrudes on both sides in the longitudinal direction, and the frame member 1 is inserted into the mounting hole 21a with the lower surface (opposing surface) of the flange portion 60 of the frame member 1 facing the upper surface (contact surface) of the metal base 21. Then, after alignment by a method described in detail later, the screw 61 as a fastening member is fixed to the metal base 21 through the through hole 60a formed in the flange portion 60 of the frame member 1, and the aligned liquid ejection head 23 is fastened to the metal base 21.

The liquid ejection head 23 and the metal base 21 can be fastened together by means of screws, adhesives, spot welding, or other methods.

FIG. 5 is an explanatory diagram showing an example in which the liquid ejection unit 20 is attached to the main body of an image forming apparatus.
The liquid ejection unit 20, in which a plurality of liquid ejection heads 23 are assembled to the metal base 21, is attached to the main body of an image forming apparatus such as an inkjet recording apparatus. As shown in Fig. 5, the metal base 21 is abutted against three reference pins 24A, 24B, and 24C on a main body base 24 provided on the main body of the image forming apparatus, and then the metal base 21 is fixed to the main body base 24 with fixing bolts.

Figure 5 shows an example in which 12 liquid ejection heads 23 are arranged in two rows in a staggered pattern in the longitudinal direction (main scanning direction) of the main body base 24 on one metal base 21. An image can be formed by ejecting ink droplets from each liquid ejection head 23 of the liquid ejection unit 20 while moving the recording material in the vertical direction (sub-scanning direction) of Figure 5. Also, by appropriately increasing the number of metal bases 21 in one inkjet recording device, it is possible to increase the number of colors or the number of dots per inch (dpi).

In the liquid ejection unit 20, in order for ink droplets ejected from each liquid ejection head 23 to land at the intended landing position on the recording material, the multiple liquid ejection heads 23 must be precisely positioned (aligned) and fixed (bonded) to a predetermined position on the metal base 21. In particular, the precision of the alignment (hereinafter referred to as "alignment in the plane direction") of each liquid ejection head 23 relative to the metal base 21 (the plane direction of the upper surface of the metal base 21) and the parallelism of each liquid ejection head 23 relative to the metal base 21 (parallelism of the ejection surface of each liquid ejection head 23 relative to the upper surface of the metal base 21) are important.

As shown in FIG. 6(a), the accuracy of the surface alignment is determined by the positional accuracy in the X and Y directions on the surface of the metal base 21, and the accuracy of the rotation angle θ around the normal axis (Z-axis) of the surface of the metal base 21. Also, the parallelism is determined by the accuracy of the rotation angle δ around the Y-axis, as shown in FIG. 6(b).

Next, an assembly device for the liquid ejection unit 20 of this embodiment will be described.
FIG. 7 is a perspective view showing the main parts of an assembly device for assembling the liquid discharge unit 20 according to this embodiment.
When assembling the liquid ejection head 23 to the metal base 21, first, the metal base 21 is fixed onto a unit base fixing table 25 of an assembly device having a configuration similar to that of the main body base 24 of the image forming apparatus shown in Fig. 5. That is, three reference pins 25A, 25B, and 25C are provided on the unit base fixing table 25, and the metal base 21 abuts against the reference pin 25A in the X direction and against the reference pins 25B and 25C in the Y direction, and is fixed to the unit base fixing table 25 with screws in this abutting state. The X direction corresponds to the long dimension direction of the metal base 21, and the Y direction corresponds to the short dimension direction of the metal base 21.

The unit base fixing table 25 is a table that is hollow in the Y direction, which is the optical axis direction of the CCD camera 50 serving as an imaging means, and is fixed on the XY stage 30 serving as a moving means. The XY stage 30 has the same configuration as a known general XY stage, and is composed of, for example, an X-direction moving section that can move along the X direction by a linear driving means, and a Y-direction moving section that can move along the Y direction by another linear driving means fixed on the X-direction moving section. The unit base fixing table 25 is fixed on the Y-direction moving section of the XY stage 30, and the unit base fixing table 25 can be moved to target positions in the X and Y directions by the XY stage 30.

The CCD camera 50 is equipped with an imaging element consisting of a CCD. The imaging element may be another imaging element such as a C-MOS. The camera tip, which is equipped with an optical system such as an imaging lens of the CCD camera 50, is arranged so as to be located in a hollow portion 25a inside the unit base fixing stand 25, and the hollow portion 25a is open so that the camera tip does not interfere with the unit base fixing stand 25 within the X-direction movable range of the XY stage 30.

The metal base 21 is moved at a predetermined pitch by the XY stage 30 and accurately positioned at the target position. At this time, the pitch is determined by the positioning accuracy of the XY stage 30, and the X direction is position feedback controlled so that the XY stage 30 is accurately positioned at the target position based on information from a position detection means composed of a linear scale 26x and a reading sensor that reads this linear scale 26x. Similarly, the Y direction is position feedback controlled so that the XY stage 30 is accurately positioned at the target position based on information from a position detection means composed of a linear scale 26y and a reading sensor that reads this linear scale 26y.

The XY stage 30 is placed on a θ stage 37 that serves as an adjustment means. The θ stage 37 has the same configuration as a known general θ stage, and is composed of, for example, a θ direction moving part that can move around the Z axis (θ direction) that extends in the Z direction perpendicular to both the X direction and the Y direction. The XY stage 30 is fixed on the θ direction moving part of the θ stage 37, and the XY stage 30 can be moved to a target rotation angle in the θ direction by the θ stage 37.

By placing the XY stage 30 on the θ stage 37 in this way, the alignment operation using the θ stage 37 (the operation of moving the XY stage 30 to the target rotation angle in the θ direction) does not affect the pitch feed operation of the metal base 21 by the XY stage 30 (the operation of moving the metal base 21 in the X and Y directions at a predetermined pitch interval). In addition, when assembling the liquid ejection head 23 to the metal base 21, the metal base 21 is aligned by the θ stage 37 while the liquid ejection head 23 is fixed and held by a clamping means that moves up and down by the pressure stage. High assembly accuracy in the surface direction (XY surface direction) can be ensured by the positioning accuracy of the XY stage 30 and the alignment accuracy of the θ stage 37.

FIG. 8 is a perspective view showing the overall configuration of an assembly device for assembling the liquid discharge unit 20 according to this embodiment.
The pressure stage 36 can move the clamping means 34 up and down while gripping the liquid ejection head 23. The pressure stage 36 is fixed onto a housing base 45. The pressure stage 36 is composed of a pressure actuator 39 capable of controlling the load, a guide mechanism 40, and a pressure table 41. The pressure actuator 39 can control the position and load by using an electro-pneumatic actuator.

This pressure stage 36 is used to bring the upper surface of the metal base 21 into contact with the lower surface of the flange 60 of the liquid ejection head 23 with weak pressure, and while this weak pressure contact state is maintained, the metal base 21 is aligned (positioned) in a predetermined position relative to the liquid ejection head 23 using the XY stage 30 and the θ stage 37. Once alignment is complete, the pressure stage 36 is used to increase the pressure pressing the liquid ejection head 23 against the metal base 21, and each liquid ejection head 23 is fastened to the metal base 21 with the screws 61.

A joint surface copying mechanism 38 is disposed on the underside of the pressure table 41, and a clamping means 34 is attached to the underside of the joint surface copying mechanism 38, and the liquid ejection head 23 is fixed and held by this clamping means 34.

Next, alignment of the liquid ejection head 23 and the metal base 21 in this embodiment will be described.
Conventionally, alignment in the planar direction of the metal base 21 (planar alignment) is performed in a weak contact state in which the lower surface (opposing surface) of the flange portion 60 of the liquid ejection head 23 is in contact with the upper surface (contacted surface) of the metal base 21. At this time, parallelism between the liquid ejection head 23 and the metal base 21 (parallelism of the ejection surface of the liquid ejection head 23 with respect to the upper surface of the metal base 21) is also achieved.

To obtain high parallelism with a conventional liquid ejection head, it is necessary to ensure sufficient flatness and parallelism for each of the upper surface of the metal base 21 and the lower surface of the flange portion 60 of the liquid ejection head 23 that abuts against it. However, in this case, since the contact area of each of the abutting surfaces is large, it is difficult to obtain sufficient flatness and parallelism over the entire contact area due to the part molding accuracy or part processing accuracy. Therefore, if sufficient flatness and parallelism are not obtained over the entire contact area as shown in Figure 9, it is difficult to obtain high-precision parallelism between the liquid ejection head 23 and the metal base 21.

On the other hand, one method of achieving high parallelism is to provide a protruding seat portion 62 on the underside of the flange portion 60 of the liquid ejection head 23, and to abut the upper surface of the metal base 21 with the seat surface 62a' of the protruding seat portion 62', as shown in Figures 10(a) and (b). With this configuration, the area of the seat surface 62a' is smaller than the area of the entire underside of the flange portion 60, so the contact area of each surface that requires flatness and parallelism is narrow. As a result, it is easy to obtain sufficient flatness and parallelism over the entire contact area, and it becomes easy to obtain parallelism between the liquid ejection head 23 and the metal base 21 with high precision.

However, it has been confirmed that while providing such a protruding seat portion 62' makes it easier to obtain a high degree of parallelism, the alignment accuracy of the surface direction alignment may decrease. As a result of the inventor's research into the cause, it was found that the main cause is that during surface direction alignment, the peripheral edge of the seat surface 62a' of the protruding seat portion 62' gets caught on the upper surface of the metal base 21, preventing smooth relative movement in the surface direction between the metal base 21 and the liquid ejection head 23, thereby decreasing the alignment accuracy in the surface direction.

That is, when performing surface alignment, the pressure stage 36 is used to bring the upper surface of the metal base 21 into contact with the seat 62a' of the protruding seat portion 62' provided on the underside of the flange portion 60 of the liquid ejection head 23 under weak pressure. With this weak contact state maintained, the metal base 21 is aligned (positioned) at a predetermined position relative to the liquid ejection head 23 by the XY stage 30 and the θ stage 37. When the metal base 21 and the liquid ejection head 23 move relative to each other by the XY stage 30 and the θ stage 37, the peripheral edge of the seat 62a' of the protruding seat portion 62' gets caught on the upper surface of the metal base 21, hindering high-precision alignment (positioning).

Fig. 11(a) is a plan view showing an example of a protruding seat portion in this embodiment, and Fig. 11(b) is a side view showing an example of the protruding seat portion in this embodiment.
In this embodiment, as shown in Figures 11(a) and (b), a configuration is adopted in which the peripheral portion of the seating surface 62a of the protruding seating surface portion 62 is chamfered to provide a chamfered portion 62b. This chamfering shortens the edge length of the peripheral portion of the seating surface 62a of the protruding seating surface portion 62. This chamfering also makes the peripheral portion of the seating surface 62a of the protruding seating surface portion 62 have an obtuse angle. Furthermore, if burrs are generated on the peripheral portion of the seating surface 62a of the protruding seating surface portion 62, the burrs are removed by this chamfering. As a result of at least one of these, the peripheral portion of the seating surface 62a of the protruding seating surface portion 62 is less likely to get caught on the upper surface of the metal base 21, and the relative movement in the surface direction between the metal base 21 and the liquid ejection head can be smoothly performed during surface direction alignment.

In this embodiment, four protruding seating portions 62 are arranged on each of the undersides of the two flange portions 60, for a total of eight protruding seating portions 62; however, the number and arrangement of the protruding seating portions 62 are not limited to those in this embodiment, so long as they are a number and arrangement that can easily achieve a high degree of parallelism.

Fig. 12(a) is a plan view showing another example of the protruding seating surface portion in this embodiment, and Fig. 12(b) is a side view showing another example of the protruding seating surface portion in this embodiment.
In this embodiment, as shown in Fig. 12(a), the shape of the seat 63a of the protruding seat portion 63 may be elongated in a predetermined direction. Note that, as shown in Figs. 12(a) and 12(b), the protruding seat portion 63 in this example also has a chamfered portion 63b formed by chamfering the peripheral portion of the seat 63a of the protruding seat portion 63. Therefore, the peripheral portion of the seat 62a of the protruding seat portion 62 is less likely to get caught on the upper surface of the metal base 21, and the metal base 21 and the liquid ejection head can smoothly move relative to each other in the planar direction during planar positioning.

In this example, the shape of the seat surface 63a is elongated in the Y direction, as shown in FIG. 12(a). This is for the following reasons.

That is, in this embodiment, when performing surface alignment, the liquid ejection head 23 is gripped from both sides in the X direction by the clamping means 34 of the assembly device. In this case, the clamping means 34 receives the external force in the X direction (particularly the external force caused by the peripheral edge of the seat getting caught) that the liquid ejection head 23 receives from the upper surface of the metal base 21 during surface alignment. Therefore, the relative movement in the X direction is less affected by the peripheral edge of the seat, and even if the peripheral edge of the seat gets caught to some extent, the relative movement in the X direction is less likely to be hindered.

In contrast, external forces in the Y and θ directions cannot be received by the clamping means 34, and are therefore easily affected by the periphery of the seat during relative movement in the Y and θ directions. Therefore, if the periphery of the seat gets caught slightly, relative movement in the Y and θ directions is hindered, which can easily reduce the accuracy of the surface alignment.

As shown in the example in Figures 12(a) and (b), by making the shape of the seat 63a of the protruding seat portion 63 long in the X direction (the direction in which it is gripped by the clamping means 34 during surface alignment), the seat peripheral portion (the upper end and lower end of the seat 63a in Figure 12(a)) that crosses in the direction of relative movement in the Y direction or the θ direction becomes a short portion. This minimizes the occurrence of the seat peripheral portion getting caught during relative movement in the Y direction or the θ direction, suppresses the obstruction of relative movement in the Y direction or the θ direction, and suppresses a decrease in the accuracy of surface alignment.

On the other hand, during relative movement in the X direction, the seat peripheral portion (the left and right ends of the seat surface 63a in FIG. 12(a)) that crosses the direction of relative movement becomes a long portion, and so the seat peripheral portion is prone to getting caught. However, as described above, external forces in the X direction are received by the clamping means 34, so the seat peripheral portion is less likely to be affected during relative movement in the X direction. Therefore, relative movement in the X direction is not hindered, and there is no decrease in the accuracy of the surface alignment.

Therefore, as in the example shown in Figures 12(a) and (b), by making the shape of the seat surface 63a elongated in the X direction, the accuracy of the surface alignment can be further improved.

The shape of the surface long in the X direction is not limited to an oval or elliptical shape with curved ends in the long direction, as in the example shown in Figures 12(a) and (b). For example, the long end may be acute-angled or tapered (so-called boat-shaped), as in the example shown in Figures 13(a) and (b).

Next, an example of an image forming apparatus (apparatus for ejecting liquid) having the liquid ejection unit 20 equipped with the above-mentioned liquid ejection head 23 will be described.
14, a printing apparatus 500 which is an image forming apparatus includes a carry-in means 501 which carries in a continuous web 510 which is a recording material, and a guide/convey means 503 which guides and conveys the continuous web 510 carried in by the carry-in means 501 towards a printing means 505. The printing apparatus 500 also includes a printing means 505 which performs a printing operation of ejecting liquid onto the continuous web 510 to form an image, a drying means 507 which dries the continuous web 510 to which the liquid has adhered, a conveying means 509 which conveys the continuous web 510, etc.

The continuous web 510 is sent out from the original winding roller 511 of the carrying-in means 501, guided and transported by rollers of the carrying-in means 501, the guiding and transporting means 503, the drying means 507, and the carrying-out means 509, and wound up by the take-up roller 591 of the carrying-out means 509. The continuous web 510 is transported on the transport guide member 559 in the printing means 505, facing the head unit 550 equipped with the liquid ejection unit 20, and an image is printed by the liquid ejected from the head unit 550.

In the above, in this embodiment, an example of an integrated liquid ejection unit in which multiple liquid ejection heads 23 are assembled to a metal base 21 in a staggered arrangement in two rows, which is used in an inkjet recording device, which is an image forming device using a liquid ejection recording method, has been described. However, this is not limited to this. The present invention can be applied to other devices in which multiple liquid ejection heads 23 are attached to a predetermined position on a metal base 21 for the purpose of increasing color, length, density, etc., regardless of whether they are line heads or serial heads, and the same effects can be obtained. Furthermore, the present invention can be applied to any writing unit in which a writing head such as an organic LED head is assembled to a predetermined position on a metal base 21, not limited to liquid ejection heads, and the same effects can be obtained.

In the present invention, the liquid used is not particularly limited as long as it has a viscosity and surface tension that allows it to be discharged from the head, but it is preferable that the viscosity is 30 mPa·s or less at room temperature and pressure, or by heating and cooling. More specifically, the liquid may be a solvent such as water or an organic solvent, a colorant such as a dye or pigment, a functionalizing material such as a polymerizable compound, a resin, or a surfactant, a biocompatible material such as DNA, amino acids, proteins, or calcium, an edible material such as a natural pigment, or a solution, suspension, or emulsion containing the above. These may be used, for example, as inkjet ink, a surface treatment liquid, or a material liquid for three-dimensional modeling.

The energy sources that generate the liquid include piezoelectric actuators (laminated piezoelectric elements and thin-film piezoelectric elements), thermal actuators that use electrothermal conversion elements such as heating resistors, and electrostatic actuators that consist of a vibration plate and an opposing electrode.

A "liquid ejection unit" is a liquid ejection head integrated with functional parts and mechanisms, and includes a collection of parts related to ejecting liquid. For example, a "liquid ejection unit" includes a combination of a liquid ejection head and at least one of the following components: a head tank, a carriage, a supply mechanism, a maintenance and recovery mechanism, a main scanning movement mechanism, and a liquid circulation device.
Here, integration includes, for example, a liquid ejection head and a functional part or mechanism fixed to each other by fastening, adhesion, engagement, etc., and one is held movably relative to the other. In addition, the liquid ejection head and the functional part or mechanism may be detachable from each other.

There are liquid ejection units in which the liquid ejection head and head tank are integrated, and in which the two are integrated by being connected to each other via a tube or the like. Here, it is also possible to add a unit containing a filter between the liquid ejection head and head tank of these liquid ejection units.

There are also liquid ejection units in which the liquid ejection head and carriage are integrated, and in which the liquid ejection head, carriage, and main scanning movement mechanism are integrated. There are also liquid ejection units in which the liquid ejection head is movably held by a guide member that constitutes part of the scanning movement mechanism, and the liquid ejection head and scanning movement mechanism are integrated.

Some liquid ejection units have a cap member, which is part of the maintenance and recovery mechanism, fixed to a carriage on which a liquid ejection head is attached, integrating the liquid ejection head, carriage, and maintenance and recovery mechanism. Other liquid ejection units have a tube connected to a liquid ejection head on which a head tank or flow path components are attached, integrating the liquid ejection head and supply mechanism. Liquid from a liquid storage source is supplied to the liquid ejection head via this tube.

The main scanning movement mechanism includes the guide member alone. The supply mechanism includes the tube alone and the loading section alone.

In this invention, the liquid ejection unit is described in combination with a liquid ejection head, but the liquid ejection unit also includes a head module including the liquid ejection head described above, or a head unit that is integrated with the functional parts and mechanisms described above.

Devices that eject liquid include devices that are equipped with a liquid ejection head, a liquid ejection unit, a head module, a head unit, etc., and that eject liquid by driving the liquid ejection head. Devices that eject liquid include not only devices that can eject liquid onto objects to which the liquid can adhere, but also devices that eject liquid into gas or liquid.

Devices that eject liquid can also include means for feeding, transporting, and discharging objects onto which liquid can be attached, as well as other pre-processing and post-processing devices. For example, devices that eject liquid include image forming devices that eject ink to form an image on a recording medium, and three-dimensional modeling devices that eject modeling liquid onto a powder layer formed from layers of powder in order to form a three-dimensional object (a three-dimensional model).

Furthermore, devices that eject liquid are not limited to those that use the ejected liquid to visualize meaningful images such as letters and figures. For example, devices that form patterns that have no meaning in themselves and devices that create three-dimensional images are also included.

The above-mentioned object to which liquid can adhere means an object to which liquid can adhere at least temporarily, and to which the liquid adheres and sticks or adheres and penetrates. Specific examples include recording media such as paper, film, and cloth, electronic circuit boards, electronic components such as piezoelectric elements, powder layers, organ models, and test cells, and all objects to which liquid can adhere are included unless otherwise specified. The material to which liquid can adhere may be any material, such as paper, thread, fiber, cloth, leather, metal, plastic, glass, wood, ceramics, etc., as long as the liquid can adhere even temporarily.

Devices that eject liquid include configurations in which a liquid ejection head and an object to which liquid can be attached move relatively, but are not limited to only one of the moving objects. Specific examples include both serial-type devices that move a liquid ejection head and line-type devices that do not move a liquid ejection head.

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

Although the preferred embodiment of the present invention has been described above, the present invention is not limited to such a specific embodiment, and various modifications and alterations are possible within the scope of the spirit of the present invention described in the claims unless otherwise specifically limited in the above description. The effects described in the embodiments of the present invention are merely examples of the most preferable effects resulting from the present invention, and the effects of the present invention are not limited to those described in the embodiments of the present invention.

The above description is merely an example, and each of the following aspects provides unique effects.
[First aspect]
The first aspect is a liquid ejection head 23 held by a head holding member (e.g., a metal base 21), and has protruding seating portions 62, 63 that protrude from an opposing surface (e.g., the lower surface of the flange portion 60) that faces the contacted surface (e.g., the upper surface) of the head holding member and abut on the contacted surface, and is characterized in that the peripheral portions of the seating surfaces 62a, 63a of the protruding seating portions are chamfered.
When aligning a liquid ejection head with a head holding member, in a conventional liquid ejection head, the opposing surface of the head holding member that faces the abutted surface is abutted against the abutted surface, and alignment in the surface direction of the abutted surface (surface direction alignment) is performed. In addition, at this time, it is required to obtain parallelism between the liquid ejection head and the head holding member (parallelism of the ejection surface of the liquid ejection head with respect to the abutted surface of the head holding member).
In order to obtain a high degree of parallelism with a conventional liquid ejection head, it is necessary to ensure sufficient flatness and parallelism for each of the abutting surface of the head holding member and the opposing surface of the liquid ejection head that abuts thereon. However, in a conventional liquid ejection head, the abutting areas of the respective abutting surfaces are large, so it is difficult to obtain sufficient flatness and parallelism over the entire abutting area due to the component molding accuracy or component processing accuracy, and it is difficult to obtain a high degree of parallelism between the liquid ejection head and the head holding member.
On the other hand, a method for obtaining a high degree of parallelism is to provide a protruding seating portion on the opposing surface of the liquid ejection head, and to abut the seating surface of the protruding seating portion against the contacted surface of the head holding member. With this configuration, the area of the seating portion is smaller than that of the opposing surface, so that the contact areas of the surfaces that require flatness and parallelism are narrow, making it easier to obtain sufficient flatness and parallelism over the entire contact area, and facilitating the obtaining of highly accurate parallelism between the liquid ejection head and the head holding member.
However, when such a protruding seating portion is provided, it is easy to obtain a high degree of parallelism, but it has been confirmed that the alignment accuracy in the surface direction may decrease. As a result of the inventor's research into the cause, it was found that the main cause is that, during alignment in the surface direction, the edge of the peripheral portion of the seating surface of the protruding seating portion gets caught on the contact surface of the head holding member, preventing smooth relative movement in the surface direction between the head holding member and the liquid ejection head, thereby decreasing the alignment accuracy in the surface direction.
Therefore, in this embodiment, a configuration is adopted in which the peripheral portion of the seat of the protruding seat portion is chamfered. This makes it difficult for the peripheral portion of the seat of the protruding seat portion to get caught on the contact surface of the head holding member, and enables smooth relative movement in the surface direction between the head holding member and the liquid ejection head during surface direction alignment. Therefore, according to this embodiment, while ensuring high parallelism by providing the protruding seat portion, it is possible to prevent the peripheral portion of the seat of the protruding seat portion from getting caught on the contact surface of the head holding member, thereby ensuring high alignment accuracy during surface direction alignment. Therefore, it is possible to provide a liquid ejection head that can perform surface direction alignment with the head holding member with high accuracy while ensuring high parallelism.

[Second aspect]
A second aspect is the first aspect, characterized in that the shape of the seat surface is elongated in a predetermined direction.
According to this, the direction in which the liquid ejection head is gripped during alignment in the planar direction is made to coincide with the predetermined direction, so that the accuracy of alignment in the planar direction can be improved.

[Third aspect]
A third aspect is the second aspect, characterized in that the shape of the seat surface is such that the end portions in the longitudinal direction are curved or acute-angled.
This makes it possible to further improve the accuracy of the alignment in the planar direction.

[Fourth aspect]
A fourth aspect is any one of the first to third aspects, characterized in that the head holding member further comprises a fastening member (e.g., a screw 61) for fastening the opposing surface to the contacted surface.
According to this, the contact surface of the head holding member and the seat surface of the protruding seat portion on the opposing surface can be brought into close contact with each other by fastening, and a high degree of parallelism can be obtained between the head holding member and the liquid ejection head.

[Fifth aspect]
The fifth aspect is a liquid ejection unit 20 in which one or more liquid ejection heads 23 are held on a head holding member (e.g., a metal base 21), and is characterized in that the liquid ejection head is any of the liquid ejection heads of the first to fourth aspects.
It is possible to provide a liquid ejection unit in which parallelism between the head holding member and the liquid ejection head is ensured and high accuracy of alignment in the surface direction is obtained.

[Sixth aspect]
A sixth aspect is a liquid ejection device comprising the liquid ejection head according to any one of the first to fourth aspects or the liquid ejection unit according to the fifth aspect.
It is possible to provide a liquid ejecting device in which parallelism between the head holding member and the liquid ejection head is ensured and high accuracy of alignment in the surface direction is obtained.

[Seventh aspect]
The seventh aspect is a manufacturing method for a liquid ejection unit 20 in which one or more liquid ejection heads 23 are held by a head holding member (e.g., a metal base 21), characterized in that the method includes an alignment step of aligning the liquid ejection head with respect to the head holding member while abutting the seating surfaces 62a, 63a of protruding seating portions 62, 63 protruding from an opposing surface of the liquid ejection head (e.g., the lower surface of the flange portion 60) that faces the abutting surface (e.g., the upper surface) of the head holding member, and a fixing step of fixing the liquid ejection head to the head holding member after the alignment step.
This makes it possible to manufacture a liquid ejection unit in which parallelism between the head holding member and the liquid ejection head is ensured and high accuracy of alignment in the surface direction is obtained.

1: Frame member 2: Vibration plate 3: Flow path plate 4: Nozzle plate 5: Multilayer piezoelectric element 6: PZT base 7: FPC
8: common liquid chamber 9: pressurized liquid chamber 10: fluid resistance portion 11: nozzle hole 12: communication hole 13: convex portion 14: diaphragm portion 15: ink inlet 16: ink supply port 20: liquid ejection unit 21: metal base 21a: mounting hole 22: outer part 23: liquid ejection head 24: main body base 24A to 24C: reference pin 25: unit base fixing base 25A to 25C: reference pin 25a: hollow portion 26x, 26y: linear scale 30: XY stage 34: clamping means 36: pressurized stage 37: θ stage 39: pressurized actuator 40: guide mechanism 41: pressurized table 45: housing base 50: CCD camera 60: flange portion 60a: through hole 61 : Screws 62', 62, 63: Protruding seating surface portions 62a', 62a, 63a: Seat surfaces 62b, 63b: Chamfered portions 500: Printing device

JP 2015-163463 A

Claims (7)

A liquid ejection head held by a head holding member,
a protruding seat portion protruding from an opposing surface of the head holding member that faces the abutted surface and abuts against the abutted surface,
The liquid ejection head is characterized in that the peripheral edge of the seating surface of the protruding seating surface portion is chamfered. 2. The liquid ejection head according to claim 1,
The liquid ejection head is characterized in that the seating surface has a shape that is elongated in a predetermined direction. 3. The liquid ejection head according to claim 2,
The liquid ejection head is characterized in that the shape of the seat surface is such that the ends in the longitudinal direction are curved or acute-angled. 4. The liquid ejection head according to claim 1,
a fastening member for fastening the facing surface to the contact surface of the head holding member; A liquid ejection unit in which one or more liquid ejection heads are held by a head holding member,
A liquid ejection unit comprising the liquid ejection head according to claim 1 as the liquid ejection head. A device for discharging liquid, comprising:
A liquid ejection device comprising the liquid ejection head according to claim 1 . A method for manufacturing a liquid ejection unit in which one or more liquid ejection heads are held by a head holding member, comprising the steps of:
a positioning step of positioning the liquid ejection head with respect to the head holding member in a state in which a seating surface of a protruding seating surface portion protruding from an opposing surface of the liquid ejection head opposing the opposing surface of the head holding member is brought into contact with the opposing surface;
A method for manufacturing a liquid ejection unit, comprising the steps of: fixing the liquid ejection head to the head holding member after the positioning step.

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