JP6790857B2 - Liquid injection head and liquid injection device - Google Patents

Description

The present invention relates to a liquid injection head such as an inkjet recording head, and a liquid injection device including the liquid injection head, and in particular, a liquid injection head including a flow path member formed by laminating a plurality of flow path components. , And the liquid injection device.

The liquid injection device includes a liquid injection head, and is a device that injects (discharges) various liquids from the injection head. As this liquid injection device, for example, there are image recording devices such as an inkjet printer and an inkjet plotter, but recently, various types of liquid injection devices have been manufactured by taking advantage of the feature that a very small amount of liquid can be accurately landed at a predetermined position. It is also applied to devices. For example, a display manufacturing device that manufactures color filters such as liquid crystal displays, an electrode forming device that forms electrodes such as an organic EL (Electro Luminescence) display and a FED (field emission display), and a chip that manufactures a biochip (biochemical element). It is applied to manufacturing equipment. Then, the recording head for the image recording device injects liquid ink, and the color material injection head for the display manufacturing device injects solutions of R (Red), G (Green), and B (Blue). Further, the electrode material injection head for the electrode forming apparatus injects a liquid electrode material, and the bioorganic material injection head for the chip manufacturing apparatus injects a solution of the bioorganic substance.

The liquid injection head introduces a liquid from a liquid supply source that stores the liquid, and injects the liquid as droplets from a nozzle by driving a driving element such as a piezoelectric element or a heat generating element. Some of the liquid injection heads have a liquid flow path in which a plurality of components are laminated. For example, the liquid injection head disclosed in Patent Document 1 has a first flow path member, a filter, and a second flow path member in an upper and lower case member including an upper case member and a lower case member. It is configured to accommodate the flow path member including it. Further, a seal member (bush) made of an elastic material is provided between the flow path portion including the upper case member and the flow path member and the lower case member, and the seal member causes the flow path portion side. The flow path and the flow path on the lower case member side are liquidtightly communicated with each other through the through port of the seal member. In this configuration, the seal member is provided with an open air passage, and the space on the inner peripheral side of the seal member and the atmosphere on the outer peripheral side are communicated with each other. Therefore, the space on the lower side of the seal member and the space generated between the seal member and the flow path portion are open to the atmosphere through this open air path. This open air passage is formed by a narrow groove formed on the upper surface of the annular seal portion of the seal member and a flow path member in close contact with the upper surface of the annular seal portion.

Japanese Unexamined Patent Publication No. 2015-051623

By the way, in the above configuration, since the upper case member is only fixed to the lower case member from the lower side of the case by, for example, screwing or caulking, the inside of the upper and lower case members is airtight and liquidtight. Is not secured. Further, since the general elastomer used as a sealing member does not have an enhanced gas barrier property, the moisture (solvent component) in the liquid flow path uses the material of the sealing member as water vapor in addition to the above-mentioned open path to the atmosphere. It permeates and diffuses into the atmosphere. Therefore, there is a problem that the thickening of the liquid in the liquid flow path of the flow path member progresses.

The present invention has been made in view of such circumstances, and an object of the present invention is a liquid injection head capable of suppressing thickening of a liquid in a liquid flow path in a flow path member, and a liquid injection device. Is to provide.

The liquid injection head of the present invention has been proposed in order to achieve the above object, and includes a first case for accommodating a flow path member in which a liquid flow path is formed, and a first case.
A second case with a head unit and
A sealing member having a connecting portion that seals the liquid flow path on the first case side and the liquid flow path on the second case side and connects them in a liquid-tight manner.
A liquid injection head that injects a liquid from the flow path member from a nozzle of the head unit.
A flow path isolation member having a gas barrier property higher than that of the seal member is arranged between the first case and the seal member.
The flow path member is characterized in that the flow path isolation member is joined to the first case and arranged in a sealing space defined in the first case.

According to the present invention, the flow path member is arranged in the sealing space defined in the first case by joining the flow path isolation member having a high gas barrier property to the first case. Evaporation of the water content (solvent component) of the liquid in the liquid flow path in the flow path member arranged in the sealing space is suppressed. As a result, thickening of the liquid in the liquid flow path in the flow path member is suppressed.

In the above configuration, it is desirable that the first case adopts a configuration having a high gas barrier property as compared with the sealing member.

According to this configuration, since the flow path separating member is joined to the first case having a higher gas barrier property than the sealing member to define the sealing space, the flow path member arranged in the sealing space is formed. Evaporation of the water content of the liquid in the liquid flow path in the above is more reliably suppressed.

In the above configuration, the seal member has an outer wall along the outer periphery, and the outer wall is brought into close contact with the flow path isolation member and the component member on the second case side, respectively, thereby causing the connection portion. It is desirable to adopt a configuration that seals the space in which the is arranged.

According to this configuration, the outer wall of the sealing member abuts and adheres to the flow path isolating member and the component member on the second case side, respectively, so that the space in which the connecting portion is arranged is sealed. Since the connection portion between the liquid flow path on the first case side and the liquid flow path on the second case side is doubly sealed, the liquid flow path on the first case side and the liquid flow path on the second case side are double-sealed. Evaporation of liquid water (solvent) in the liquid flow path from the connection with the road is suppressed.

In the above configuration, the flow path isolation member has a groove extending along the outer periphery at a portion of the seal member that is in contact with the outer wall, and the outer wall is brought into contact with the portion to cause a resistance passage. Is formed,
The resistance passage can adopt a configuration that communicates with the sealing space and also with an open air passage connected to the atmosphere.

According to this configuration, the resistance passage opens the sealing space to the atmosphere while suppressing the evaporation of water from the liquid flow path in the sealing space (while maintaining a high humidity state), so that the pressure change in the sealing space can be prevented. It can be relaxed.

In the above configuration, the first case has a positioning pin that defines the arrangement position of the flow path member.
The flow path member has an insertion hole through which the positioning pin is inserted.
The flow path isolation member has a recess into which the tip of the positioning pin fits.
The positioning pin adopts a configuration in which the positioning pin is inserted into the insertion hole and fitted into the recess so as to be arranged in the sealing space while being covered with the flow path member and the flow path isolation member. can do.

According to this configuration, the positioning pin is inserted into the insertion hole and fitted into the recess, so that the positioning pin is arranged in the sealing space in a state of being covered with the flow path member and the flow path isolation member. The sealing space is prevented from communicating with the atmosphere through the insertion hole through which the pin is inserted, and the flow path member and the flow path isolation member can be positioned by the positioning pin while ensuring the airtightness and liquidtightness of the sealing space. It will be possible.

Further, the first case has a positioning pin that defines the arrangement position of the flow path member.
The flow path member and the flow path isolation member have an insertion hole through which the positioning pin is inserted.
It is also possible to adopt a configuration in which the positioning pin is inserted into the insertion hole and the tip portion exposed from the insertion hole is arranged in the sealing space in a state of being sealed by a sealing material.

According to this configuration, the positioning pin is inserted into the insertion hole, and the tip portion exposed from the insertion hole is arranged in the sealing space in a state of being sealed by the sealing material, so that the positioning pin is inserted. The sealing space is prevented from communicating with the atmosphere through the insertion hole, and the flow path member and the flow path isolation member can be positioned by the positioning pin while ensuring the airtightness and liquidtightness of the sealing space. ..

In the above configuration, the flow path member is configured by laminating a plurality of flow path components.
It is desirable to adopt a configuration in which one of the flow path constituent members is the flow path isolation member.

According to this configuration, since one of the flow path component members is a flow path isolation member, it is not necessary to separately provide a flow path isolation member in addition to the flow path component members constituting the flow path member, and the liquid injection head Can be miniaturized. In addition, material costs can be reduced.

The liquid injection device of the present invention is characterized by including a liquid injection head having any of the above configurations.

According to this configuration, the thickening of the liquid in the flow path member is suppressed, so that the injection characteristics such as the weight and flight speed of the liquid injected from the nozzle are suppressed from fluctuating due to the thickening of the liquid. Therefore, reliability is improved. Further, by sealing the nozzle surface of the liquid injection head with a cap and sucking the liquid, it is possible to reduce the consumption of the liquid in the maintenance operation of discharging the thickened liquid from the nozzle.

It is a perspective view explaining the structure of the liquid injection device (printer). It is an exploded perspective view of the liquid injection head (recording head). It is sectional drawing of the liquid injection head. It is sectional drawing of the main part around a positioning pin. It is a bottom view of the second flow path member. FIG. 5 is a cross-sectional view taken along the line AA in FIG. FIG. 5 is a cross-sectional view taken along the line BB in FIG. It is sectional drawing explaining the 1st case and the atmospheric opening path of a channel member. It is sectional drawing of a head unit. It is sectional drawing of the main part around the positioning pin in 2nd Embodiment.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the accompanying drawings. In the embodiments described below, various limitations are given as suitable specific examples of the present invention, but the scope of the present invention is the scope of the present invention unless otherwise specified in the following description to limit the present invention. It is not limited to these aspects. Further, in the following, as the liquid injection device of the present invention, an inkjet printer (hereinafter, simply referred to as a printer 1) equipped with an inkjet recording head (hereinafter, simply referred to as a recording head 3) which is a kind of liquid injection head. ) Will be described as an example.

First, the configuration of the printer 1 in this embodiment will be described with reference to FIG. The printer 1 is a device that ejects liquid ink onto the surface of a recording medium 2 such as recording paper to record an image or the like. The printer 1 includes a recording head 3, a carriage 4 to which the recording head 3 is attached, and a carriage moving mechanism 5 for moving the carriage 4 in the main scanning direction. Further, the printer 1 is provided with a transport mechanism or the like that transports the recording medium 2 in the sub-scanning direction. Here, the above-mentioned ink is a kind of liquid in the present invention, and is stored in an ink cartridge 7 as a liquid supply source or a liquid storage container. The ink cartridge 7 is detachably attached to the recording head 3. It is also possible to adopt a configuration in which the ink cartridge 7 is arranged on the main body side of the printer 1 and is supplied from the ink cartridge 7 to the recording head 3 through the ink supply tube.

In the printer 1, a home position, which is a standby position of the carriage 4, is provided on one end side of the carriage 4 in the main scanning direction. A capping mechanism 6 (a type of maintenance mechanism) is arranged at this home position. The capping mechanism 6 has a tray-shaped cap 6'(sealing member) capable of contacting the nozzle surface on which the nozzle 75 (see FIG. 9) of the recording head 3 is formed. The capping mechanism 6 is configured so that the nozzle 75 of the recording head 3 can be brought into close contact with the nozzle surface in a state where the nozzle 75 of the recording head 3 faces the opening on the upper surface side of the cap 6'. By setting the cap 6'in close contact with the nozzle surface in a sealed state, a sealing empty portion is defined in the cap 6'. A pump unit (not shown) is connected to the cap 6'. The pump unit includes, for example, a suction pump such as a tube pump, and the inside of the sealed empty portion can be negatively pressured by the operation of the suction pump. Then, when the suction pump is operated in a state of close contact with the nozzle surface to create a negative pressure in the sealing space (sealed space), ink and air bubbles in the recording head 3 are sucked from the nozzle 75 to seal the cap 6'. It is designed to be discharged into the air stop. That is, the capping mechanism 6 performs a cleaning operation, which is a kind of maintenance operation for forcibly sucking and discharging thickened ink and air bubbles in the ink flow path of the recording head 3.

FIG. 2 is an exploded perspective view showing the configuration of the recording head 3, and FIG. 3 is a cross-sectional view of the recording head 3. In the following, the direction orthogonal to the nozzle surface is defined as the vertical direction with reference to the nozzle surface of the recording head 3. The recording head 3 in the present embodiment includes a first case 10 on the upper side and a second case 11 on the lower side, and a flow path member 9 is inside the first case 10 and the second case 11. , A seal member 18, a circuit board 17, a flow path connecting member 19, a plurality of head units 13, and the like are laminated and housed. Further, the flow path member 9 is configured by laminating a plurality of flow path constituent members, specifically, a first flow path member 14, a filter substrate 16, and a second flow path member 15. The first case 10 and the second case 11 are fixed to each other by, for example, a fastening member 30 such as a screw or a caulking pin in a state where the above-mentioned constituent members are housed inside.

The first case 10 is a member in which a plurality of introduction needles 22 are erected, and is compared with a sealing member 18 such as a modified polyphenylene ether (modified PPE: Zylon (registered trademark)) containing a glass filler or the like. It is made of synthetic resin with enhanced gas barrier properties. Further, each flow path constituent member (first flow path member 14, filter substrate 16, and second flow path member 15) constituting the flow path member 9 in the present embodiment is also similarly the seal member 18. It is made of synthetic resin with improved gas barrier properties. It is sufficient that at least the second flow path member 15 of the flow path constituent members of the flow path member 9 is made of a synthetic resin having an enhanced gas barrier property as compared with the seal member 18, and other flows. The road constituent member does not necessarily have to be a synthetic resin having an enhanced gas barrier property.

In the present embodiment, a total of four introduction needles 22 corresponding to the inks of the ink cartridges 7 of each color are arranged side by side along the direction corresponding to the scanning direction of the recording head 3, and the introduction needle substrate 21 in the first case 10 is arranged. It is provided on the upper surface of the. The introduction needle 22 is a hollow needle-shaped member inserted into the ink cartridge 7, and the ink stored in the ink cartridge 7 is brought to the first flow path member 14 side through an internal needle flow path (not shown). Introduce. The configuration for introducing ink from the ink cartridge 7 into the recording head 3 is not limited to the one using the introduction needle 22, and for example, a porous member capable of absorbing ink is provided on the ink supply side and the ink receiving side, respectively. It is also possible to adopt a configuration in which ink is exchanged by providing the porous members in contact with each other.

Further, as shown in FIG. 3, in the first case 10 of the present embodiment, the side wall 23 is formed from the four edges of the introduction needle substrate 21 toward the upper side and the lower side (the second case 11 side). .. In the space surrounded by the side wall 23 and the introduction needle substrate 21, the first flow path member 14 and the filter substrate 16 among the flow path constituent members in the flow path member 9 are housed. Further, a second flow path member 15 (a type of flow path isolation member in the present invention) is provided on the side wall 23 so as to close the opening on the lower surface side of the space in which the first flow path member 14 and the filter substrate 16 are housed. It is joined with the lower end surface of the. As the adhesive, an adhesive capable of ensuring the airtightness and liquidtightness of the joint portion, for example, an epoxy adhesive is used. As a result, the sealing space 12 isolated from the outside air is defined by the first case 10 and the second flow path member 15. Therefore, the liquid flow path inside the flow path member 9 (a series of flow paths including the guide flow path 31, the filter chamber 24, and the supply flow path 33, which will be described later) is housed in the sealing space 12. The sealing space 12 functions as a water evaporation control space that suppresses excessive evaporation of water that has passed through a part of the wall surface forming the liquid flow path from the internal liquid flow path. The sealing space 12 is not a completely sealed space, but is open to the atmosphere through an atmospheric opening path described later. Moisture evaporation from the flow path is suppressed while being opened to the atmosphere by a part of the resistance passage of this opening path to the atmosphere. This point will be described later.

FIG. 4 is a cross-sectional view around the positioning pin 26. A plurality of positioning pins 26 are projected downward (on the side of the second case 11) on the lower surface of the introduction needle substrate 21 in the first case 10. The positioning pin 26 is a pin for defining a relative position (arrangement position) of the flow path member 9 in a direction orthogonal to the stacking direction of the flow path constituent members. Correspondingly, the first flow path member 14 is provided with a positioning hole 27 (corresponding to the insertion hole in the present invention) through which the positioning pin 26 can be inserted, in a state of penetrating in the plate thickness direction. Similarly, the filter substrate 16 is also provided with a positioning hole 28 (corresponding to the insertion hole in the present invention) through which the positioning pin 26 can be inserted so as to penetrate in the plate thickness direction. On the other hand, the second flow path member 15 in the present embodiment is formed with a positioning recess 29 (corresponding to the recess in the present invention) into which the tip of the positioning pin 26 can be fitted. That is, the positioning recess 29 is the lower surface of the second flow path member 15 from the position corresponding to the tip end portion of the positioning pin 26 on the upper surface of the second flow path member 15 (the surface on the first case 10 side). It is formed in a recessed state without penetrating in the thickness direction of the second flow path member 15 toward the second case 11 side surface) side. Then, the positioning pin 26 is inserted into the positioning holes 27 and 28 of the first flow path member 14 and the filter substrate 16, respectively, and the tip end portion thereof is fitted into the positioning recess 29 of the second flow path member 15. When the first flow path member 14, the filter substrate 16, and the second flow path member 15 are laminated, the relative positions of these flow path constituent members are defined. Further, the positioning pin 26 is arranged in the sealing space 12 in a state of being covered with the first flow path member 14, the filter substrate 16, and the second flow path member 15. Therefore, the sealing space 12 is prevented from communicating with the atmosphere through the positioning holes 27 and 28 through which the positioning pin 26 is inserted, and the positioning pin 26 ensures the airtightness and liquidtightness of the sealing space 12. Positioning of the flow path constituent members becomes possible.

In the first flow path member 14, which is one of the flow path constituent members, the guide flow path 31 that guides the ink introduced from the introduction needle 22 to the filter chamber 24 (described later) of the filter substrate 16 is the introduction needle 22. It is a member made of synthetic resin formed in plurality corresponding to. Each guide flow path 31 communicates with the introduction needle 22 on the upper surface of the first flow path member 14. Further, each guide flow path 31 extends as an independent flow path without intersecting each other in the plane direction of the first flow path member 14, and branches into two branch flow paths in the middle. Each branch flow path opens on the lower surface of the first flow path member 14 and communicates with the two filter chambers 24. In the present embodiment, a total of eight branch flow paths are formed in the first flow path member 14 corresponding to the four introduction needles 22.

The filter substrate 16 which is one of the flow path constituent members is a member in which the filter chamber 24 in which the filter 25 is arranged is formed. The filter chamber 24 is an empty portion whose upper surface side is open. The filter 25 is fixed to the bottom portion of the filter chamber 24. The filter 25 is a member that filters ink flowing down the ink flow path. For example, a filter 25 is used in which a metal is finely woven into a mesh shape or a thin metal plate material having a large number of through holes formed by plastic working. Be done. When air bubbles or foreign matter are mixed in the ink, the air bubbles or foreign matter are captured by the filter 25 in the filter chamber 24 and prevented from flowing into the head unit 13 side. Further, an outlet 32 is opened at the bottom of the filter chamber 24. The outlet 32 communicates with the supply flow path 33 of the second flow path member 15 on the lower surface of the filter substrate 16.

The second flow path member 15, which is one of the flow path constituent members and is a kind of flow path isolation member, supplies ink introduced from the filter chamber 24 side to the head flow path of each head unit 13. It is a member in which a plurality of roads 33 are formed. In the present embodiment, a total of eight supply flow paths 33 extend as independent flow paths without intersecting each other in the plane direction of the second flow path member 15. Each supply flow path 33 communicates with the outlet 32 of the filter chamber 24 on the upper surface of the second flow path member 15, and also communicates with the communication port 34 penetrating the plate thickness direction of the second flow path member 15. To do. A part of the communication port 34 communicates with the connection flow path 36 in the flow path connection portion 35 of the flow path connection member 19 through the communication hole 37 of the seal member 18 described later, and further via the connection flow path 36. It communicates with the introduction flow path 50 of the second case 11. Further, the rest of the communication port 34 communicates with the introduction flow path 50 by communicating with the introduction portion 49 of the second case 11 through the communication hole 37 of the seal member 18. That is, the sealing member 18 seals the liquid flow path on the first case 10 side and the liquid flow path on the second case 11 side and communicates with each other in a liquid-tight manner. With the communication hole 37 of the seal member 18 as a boundary, the upstream side thereof is the liquid flow path on the first case 10 side, and the downstream side is the liquid flow path on the second case 11 side. Further, in the seal member 18, the portion where the liquid flow path on the first case 10 side and the liquid flow path on the second case 11 side are connected by the communication hole 37 corresponds to the connection portion in the present invention.

FIG. 5 is a bottom view of the second flow path member 15. Further, FIG. 6 is a cross-sectional view taken along the line AA in FIG. Further, FIG. 7 is a cross-sectional view taken along the line BB in FIG. On the lower surface of the second flow path member 15, the first peripheral wall 38 is erected downward (on the side of the second case 11) so as to surround the area where the plurality of communication ports 34 are opened. A second peripheral wall 39 is similarly erected on the outside at a predetermined distance from the first peripheral wall 38. The recess formed along the outer periphery of the second flow path member 15 between the first peripheral wall 38 and the second peripheral wall 39 (the portion indicated by hatching in FIG. 5) is formed by the outer wall 51 of the seal member 18. It functions as a fitting portion 40 to be fitted. An elongated groove 41 is formed in the fitting portion 40 along the extending direction of the fitting portion 40. As shown in FIG. 6, the groove 41 is a resistance passage that is a part of the air opening path when the outer wall 51 of the seal member 18 is fitted to the fitting portion 40 and the upper end surface of the outer wall 51 is brought into contact with the fitting portion 40. To define. This resistance passage is a passage whose cross-sectional area and total length are determined so as to resist the passage of water. Further, the first through-hole 42 and the second through-hole 43 are opened at different positions in the groove 41. These first through-holes 42 and second through-holes 43 are through-holes that penetrate in the thickness direction of the second flow path member 15. As shown in FIG. 7, the first through-hole 42 communicates with the sealing space 12 in which the first flow path member 14 and the filter substrate 16 are arranged. That is, the sealing space 12 communicates with the atmosphere opening path through the first through port 42.

FIG. 8 is a cross-sectional view illustrating the path open to the atmosphere of the first case 10 and the flow path member 9. The second through-hole 43 communicates with the filter substrate 16, the first flow path member 14, and the atmospheric open passage 44 formed in the first case 10. The atmosphere opening passage 44 includes a first atmospheric communication passage 45 provided on the filter substrate 16, a second atmospheric communication passage 46 provided on the first flow path member 14, and an introduction needle substrate 21 of the first case 10. It is a part of the atmospheric opening path configured by connecting the third atmospheric passage 47 provided in the above in a series. The passage cross-sectional area of the open air passage 44 is set sufficiently larger than the passage cross-sectional area of the resistance passage. Further, the other end of the air opening path 44 opposite to one end communicating with the second through port 43 communicates with the atmosphere from the atmosphere opening 48 of the first case 10. In this way, the sealing space 12 is open to the atmosphere from the atmospheric opening 48 through the resistance passage, the second through, and the atmospheric opening 44 from the first through port 42. As a result, it is possible to alleviate the pressure change in the sealing space 12 while suppressing the evaporation of water from the liquid flow path in the sealing space 12 (while maintaining the high humidity state).

A seal member 18, a circuit board 17, and a flow path connecting member 19 are arranged between the second flow path member 15 of the first case 10 and the second case 11. The seal member 18 is a member made of an elastic material such as an elastomer, and a communication hole 37 is provided at a position corresponding to the communication port 34 of the second flow path member 15. The communication hole 37 is formed between the lower end opening of the communication port 34 of the second flow path member 15 and the upper end opening of the introduction portion 49 of the second case 11, or between the lower end opening of the communication port 34 and the flow path connecting member 19. It is arranged between the flow path connecting portion 35, that is, between the liquid flow path on the first case 10 side and the liquid flow path on the second case 11 side. Then, the peripheral edge of the opening of the communication hole 37 is elastically adhered to the peripheral edge of the opening of these flow paths to seal the liquid flow path on the first case 10 side and the second. It communicates with the liquid flow path on the case 11 side in a liquidtight state. Cylindrical surrounding walls 37a (see FIGS. 2 and 3) protruding toward the first case 10 side and the second case 11 side are formed on the upper and lower peripheral edges of the communication hole 37. The upper end surface and the lower end surface of the enclosure wall 37a are in close contact with the second flow path member 15 and the circuit board 17, respectively, so that the liquid flow path on the first case 10 side and the liquid flow on the second case 11 side are brought into close contact with each other. Seal the connection with the road.

Further, the outer peripheral edge of the seal member 18 is provided with an outer wall 51 extending from the outer peripheral edge toward the first case 10 side and the second case 11 side, respectively. When the seal member 18 is arranged in a positioned state between the second flow path member 15 and the circuit board 17, the upper end portion of the outer wall 51 is placed on the fitting portion 40 of the second flow path member 15. The resistance passage is formed by abutting with the portion of the second flow path member 15 in which the groove 41 is formed by fitting. Further, the lower end portion of the outer wall 51 comes into contact with the upper surface of the circuit board 17. In a state in which the constituent members of the recording head 3 are laminated and assembled, the outer wall 51 of the seal member 18 is crushed between the second flow path member 15 and the circuit board 17, and is elastically adhered to both of them. As a result, the seal member surrounds the flow path connection space 52 (see FIG. 3) in which the connection portion between the liquid flow path on the first case 10 side and the liquid flow path on the second case 11 side is arranged. It is sealed by the outer wall 51 of 18. That is, the connection portion between the liquid flow path on the first case 10 side and the liquid flow path on the second case 11 side is doubly sealed. As a result, evaporation of water (solvent) of the ink in the liquid flow path is suppressed from the connection portion between the liquid flow path on the first case 10 side and the liquid flow path on the second case 11 side. Further, in the present embodiment, since the connecting portion is further (triple) sealed by the surrounding wall 37a and the outer wall 51, the evaporation of the water (solvent) of the ink in the liquid flow path from the connecting portion is more effective. It is suppressed.

The circuit board 17 is a so-called printed circuit board. The circuit board 17 in the present embodiment includes a connector 54 to which a flexible flat cable (FFC) 8 (see FIG. 1) from the printer main body side is connected, and receives a control signal such as a drive signal from the printer main body side through the FFC 8. It is applied to the piezoelectric element 71 (see FIG. 9) of the head unit 13 through the flexible substrate 55. That is, the circuit board 17 is a board that relays a drive signal for driving the piezoelectric element 71 as a drive element (active element). The connector 54 is arranged outside the position where the lower end surface of the outer wall 51 of the sealing member 18 is abutted and sealed. As a result, the FFC 8 can be inserted and removed from the connector 54 while maintaining the sealed state of the flow path connection space 52 in which the connection portion is arranged. The circuit board 17 is provided with an escape hole 56 through which the flexible substrate 55, the introduction portion 49 of the second case 11, and the flow path connecting portion 35 of the flow path connecting member 19 are inserted. Then, the circuit board 17 is arranged in the second case 11 in a state where the flow path connecting member 19 is interposed to close the opening on the upper surface side of the region where the flow path connecting member 19 of the second case 11 is arranged. To.

The flow path connecting member 19 is a member made of synthetic resin arranged between the circuit board 17 and the second case 11. A plurality of cylindrical flow path connecting portions 35 are projected on the upper surface of the flow path connecting member 19 in the present embodiment. The recording head 3 in the present embodiment is provided with a total of eight rows of nozzle rows, and a total of four flow path connecting portions 35 corresponding to the four rows are provided in the flow path connecting member 19. As described above, the connection flow path 36 is formed inside each flow path connection portion 35. Then, one end of the connection flow path 36 communicates with the communication port 34 of the second flow path member 15 through the communication hole 37 of the seal member 18 as described above, and the other end of the connection flow path 36 is the second. In case 11, the introduction flow path 50 communicates with the introduction flow path 50 via a planar flow path (not shown) extending parallel to the nozzle surface. Further, the flow path connecting member 19 is provided with an escape hole 57 through which the flexible substrate 55 and the introduction portion 49 of the second case 11 are inserted.

The second case 11 is a box-shaped member for accommodating a plurality of head units 13 in the accommodating chamber 59 formed inside. In the second case 11, an introduction flow path 50 communicating with a case flow path 64 (described later) in the head unit 13 in the accommodation chamber 59 is formed corresponding to each nozzle row of the head unit 13. Further, the second case 11 is divided by a partition wall 60 into upper and lower regions, that is, an region in which the flow path connecting member 19 is arranged and an region in which the accommodation chamber 59 is formed. On the upper surface of the partition wall 60, a total of four cylindrical introduction portions 49 corresponding to the remaining four rows of the eight nozzle rows are projected as upper end portions of the introduction flow path 50. Then, each introduction portion 49 communicates with the communication port 34 of the second flow path member 15 through the communication hole 37 of the seal member 18 as described above. The flow path connecting member 19 is arranged on the upper surface of the partition wall 60 in a state where each introduction portion 49 is inserted into the escape hole 57 of the flow path connecting member 19. Further, one end of the plane flow path is opened in the partition wall 60, and the connection flow path 36 of the flow path connection member 19 is communicated with the opening portion. Further, the partition wall 60 is provided with a substrate insertion port 61 through which the flexible substrate 55 is inserted. The other end of the flexible substrate 55 whose one end is connected to the piezoelectric element 71 of the head unit 13 is pulled out to the upper surface side of the circuit board 17 through the substrate insertion port 61 and the escape holes 56 and 57, and the circuit board 17 It is electrically connected to the terminal.

The storage chamber 59 of the second case 11 is open to the lower surface side of the second case 11. In the accommodation chamber 59, in the present embodiment, a total of four head units 13 are accommodated in a state of being positioned side by side in a direction corresponding to the main scanning direction. The number of head units 13 accommodated in the accommodation chamber 59 is not limited to four. The lower surface of each head unit 13 in the accommodation chamber 59 (more specifically, the lower surface of the compliance substrate 68 described later) is a metal head cover having four openings 62 corresponding to the head units 13. It is fixed to 20 with an adhesive. The head cover 20 is also bonded to the lower surface of the second case 11 with an adhesive. As a result, the space inside the second case 11 is sealed by the head cover 20 and the sealing member 18.

FIG. 9 is a cross-sectional view of a main part showing an example of the internal configuration of the head unit 13. The head unit 13 in the present embodiment is configured by being attached to a head case 65 made of synthetic resin in a state where a plurality of head unit constituent members are laminated. The head unit constituent members include a nozzle plate 66, a compliance substrate 68, a communication substrate 67, a pressure chamber forming substrate 69, a diaphragm 70, a piezoelectric element 71 (a type of drive element), a protective substrate 72, and the like.

The pressure chamber forming substrate 69 is made of a silicon single crystal substrate (hereinafter, also simply referred to as a silicon substrate). In the pressure chamber forming substrate 69, a plurality of empty spaces for partitioning the pressure chamber 73 are formed by anisotropic etching treatment on the silicon substrate. This empty portion is formed so as to penetrate the thickness direction of the pressure chamber forming substrate 69, and one opening is sealed with the diaphragm 70 and the other opening is sealed with the communication substrate 67. As a result, the pressure chamber 73 is defined. Hereinafter, the pressure chamber 73 including this empty space will be referred to. Since the nozzle plate 66 of each head unit 13 in the present embodiment is formed with two nozzle rows in which a plurality of nozzles 75 are provided, the pressure chamber forming substrate 69 has a row of pressure chambers 73. Two rows are formed corresponding to each nozzle row. The pressure chamber 73 is an empty portion that is long in a direction that intersects (orthogonally in this embodiment) the parallel direction (nozzle row direction) of the nozzles 75. When the pressure chamber forming substrate 69 is joined in a state of being positioned with respect to the communication substrate 67 described later, one end of the pressure chamber 73 in the longitudinal direction communicates with the nozzle 75 via the nozzle communication passage 74 of the communication substrate 67. To do. Further, the other end of the pressure chamber 73 in the longitudinal direction communicates with the common liquid chamber 77 through the individual communication port 76 of the communication board 67.

A diaphragm 70 is formed on the upper surface of the pressure chamber forming substrate 69 (the surface opposite to the joint surface with the communication substrate 67) in a state where the upper opening of the pressure chamber 73 is sealed. The diaphragm 70 is made of, for example, silicon dioxide having a thickness of about 1 μm. Further, an insulating film (not shown) is formed on the diaphragm 70. This insulating film is made of, for example, zirconium oxide. Then, the piezoelectric element 71 is formed at a position corresponding to each pressure chamber 73 on the diaphragm 70 and the insulating film. The piezoelectric element 71 in the present embodiment is a so-called bending mode piezoelectric element. The piezoelectric element 71 has a metal lower electrode film, a piezoelectric layer made of lead zirconate titanate (PZT) or the like, and a metal upper electrode film (all shown in the figure) on the vibrating plate 70 and the insulating film. Are sequentially laminated and patterned for each pressure chamber 73. Then, one of the upper electrode film and the lower electrode film is used as a common electrode, and the other is used as an individual electrode. Further, the diaphragm 70, the insulating film, and the lower electrode film function as a driving region when the piezoelectric element 71 is driven.

Lead electrodes extend from each piezoelectric element 71 onto the diaphragm 70, and a terminal on one end side of the flexible substrate 55 is connected to a portion corresponding to the electrode terminal of these lead electrodes. The flexible substrate 55 has a structure in which a conductor pattern is formed on the surface of a base film such as polyimide with copper foil or the like, and the conductor pattern is coated with a resist. A drive IC 78 (see FIG. 3) for driving the piezoelectric element 71 is mounted on the surface of the flexible substrate 55. Each piezoelectric element 71 is bent and deformed by selectively applying a drive signal (drive voltage) between the upper electrode film and the lower electrode film under the control of the drive IC 78.

The communication substrate 67 joined to the lower surface of the pressure chamber forming substrate 69 is a plate material made of a silicon substrate like the pressure chamber forming substrate 69. In the communication substrate 67, a common liquid chamber 77 (also referred to as a reservoir or a manifold), which is an empty portion common to each pressure chamber 73 in the pressure chamber row, is formed by anisotropic etching. The ink introduced from the introduction needle 22 flows down the liquid flow path on the first case 10 side, that is, the guide flow path 31, the filter chamber 24, and the supply flow path 33, and the communication port of the second flow path member 15. The liquid flow path on the second case 11 side, that is, the connection flow path 36, the introduction flow path 50, and the case flow path 64, sequentially flows down into the common liquid chamber 77 through the communication holes 37 of the 34 and the seal member 18. Inflow. The ink that has flowed into the common liquid chamber 77 is supplied to the pressure chamber 73 through the individual communication ports 76 formed corresponding to each pressure chamber 73.

A compliance board 68 is joined to the lower surface of the communication board 67. The compliance substrate 68 is a composite material composed of, for example, a thin compliance sheet 80 such as polyphenylene sulfide resin (PPS) and a metal sheet support plate 81 that supports the compliance sheet 80. In the region of the seat support plate 81 facing the common liquid chamber 77, a compliance opening 83 in which a part of the seat support plate 81 is removed is formed in a shape that resembles the lower surface opening of the common liquid chamber 77. Therefore, the opening on the lower surface side of the common liquid chamber 77 is sealed only with the flexible compliance sheet 80. In other words, the compliance sheet 80 partitions a part of the common liquid chamber 77.

The portion of the lower surface of the seat support plate 81 corresponding to the compliance opening 83 is sealed by the head cover 20. As a result, a compliance space 84 is formed between the flexible region of the compliance sheet 80 and the head cover 20 facing the flexible region. Then, the flexible region of the compliance sheet 80 in the compliance space 84 is displaced to the common liquid chamber 77 side or the compliance space 84 side according to the pressure fluctuation in the ink flow path, particularly in the common liquid chamber 77. Further, in the central portion of the compliance substrate 68, a substrate opening 82 that follows the outer shape of the nozzle plate 66 is provided. That is, in a state where the compliance board 68 and the nozzle plate 66 are joined to the communication board 67, the nozzle plate 66 is arranged in the board opening 82. As the compliance sheet 80, for example, a very thin metal plate such as stainless steel is used as long as it is a flexible member capable of bending in response to a pressure change in the ink flow path (common liquid chamber 77). You can also.

A protective substrate 72 is arranged on the upper surface of the pressure chamber forming substrate 69 on which the piezoelectric element 71 is formed. The protective substrate 72 is a hollow box-shaped member, and is made of, for example, a silicon substrate or the like. A wiring empty portion 85 penetrating the thickness direction of the substrate is formed in the central portion of the protective substrate 72. A connection portion between the lead electrode of the piezoelectric element 71 and one end of the flexible substrate 55 is arranged in the wiring empty portion 85. Further, in the protective substrate 72, the region facing the piezoelectric element 71, more specifically, on both sides of the wiring empty portion 85 in the direction orthogonal to the pressure chamber paralleling direction, the driving of the piezoelectric element 71 is not hindered. A storage space 86 of a size is formed. The accommodation space 86 is a space formed halfway in the substrate thickness direction from the lower surface of the protective substrate 72 (the joint surface with the pressure chamber forming substrate 69) toward the upper surface side.

The nozzle plate 66 is a plate material in which a plurality of nozzles 75 are formed in a row at a pitch corresponding to the dot formation density. A plurality of nozzles 75 are arranged in a row on the nozzle plate 66 at a predetermined pitch to form a nozzle row. In the present embodiment, two nozzle rows are formed on the nozzle plate 66 of each head unit 13. The same type (color) of ink is assigned to the two nozzle rows of the same head unit 13. In these nozzle rows, the positions of the nozzles 75 in the nozzle row direction are staggered, so that recording can be performed at a recording resolution twice the formation pitch of the nozzles 75. The nozzle plate 66 in this embodiment is made of a silicon substrate. Then, the cylindrical nozzle 75 is formed by performing dry etching on the substrate. The vertical and horizontal dimensions of the nozzle plate 66 are set smaller than the vertical and horizontal dimensions of the substrate opening 82 of the compliance board 68 and the opening 62 of the head cover 20. Then, when the nozzle plate 66 is joined in a state of being positioned with respect to the communication substrate 67, the nozzle plate 66 is arranged in these openings 62 and 82. Further, in this state, the nozzle communication passage 74 of the communication board 67 and the nozzle 75 communicate with each other.

The head case 65 is a box-shaped member made of synthetic resin, and a communication substrate 67 is joined to the lower surface side thereof. In the central portion of the head case 65, a penetrating space 88 (a part of the wiring space) is formed so as to penetrate the head case 65 in the height direction. The through empty portion 88 communicates with the wiring empty portion 85 of the protective substrate 72 to form an empty portion in which the flexible substrate 55 is accommodated. Further, on the lower surface side of the head case 65, an accommodating empty portion 79 is formed which is retracted halfway in the height direction of the head case 65 from the lower surface. The accommodating space 79 can accommodate the pressure chamber forming substrate 69, the piezoelectric element 71, the protective substrate 72, and the like on the communicating substrate 67 in a state where the head case 65 and the communicating substrate 67 are positioned and joined. It is set to a size of about. The lower end of the penetrating space 88 is open to the ceiling surface of the accommodation space 79.

Further, the head case 65 is formed with a case flow path 64 that penetrates the head case 65 in the height direction. The case flow path 64 is formed at a position outside the accommodation space 79 in the head case 65 in a direction orthogonal to the parallel pressure chamber direction. More specifically, a total of two case flow paths 64 are formed, one on each side of the accommodating empty portion 79, corresponding to each common liquid chamber 77 of the communication substrate 67. Then, in a state where the communication substrate 67 is joined to the head case 65, each case flow path 64 communicates with the corresponding common liquid chamber 77.

The head cover 20 is, for example, a metal plate material such as stainless steel. In the head cover 20 of the present embodiment, in order to expose the nozzle 75 formed on the nozzle plate 66 at a position corresponding to the nozzle plate 66 as described above, an opening 62 having a shape following the outer shape of the nozzle plate 66 is exposed. Is formed so as to penetrate in the thickness direction. In the present embodiment, the nozzle surface is formed by the lower surface of the head cover 20 in the head cover 20 and the exposed portion of the nozzle plate 66 in the opening 62.

Then, in the recording head 3 having the above configuration, the piezoelectric element 71 follows the drive signal from the drive IC 78 in a state where the flow path from the common liquid chamber 77 to the nozzle 75 through the pressure chamber 73 is filled with ink. By being driven, pressure fluctuation occurs in the ink in the pressure chamber 73, and the ink is ejected from a predetermined nozzle 75 by this pressure vibration.

As described above, in the recording head 3 according to the present invention, the second flow path member 15 which is a flow path isolation member having a high gas barrier property is joined to the first case 10 and defined in the first case 10. Since the flow path member 9 is arranged in the sealing space 12 to be formed, that is, the sealing space 12 is formed of a material having a high gas barrier property, the flow path member 9 arranged in the sealing space 12 Evaporation of the ink moisture (solvent component) in the liquid flow path is suppressed. As a result, thickening of the ink in the liquid flow path in the flow path member 9 is suppressed. Further, according to this configuration, since the thickening of the ink of the flow path member 9 is suppressed, it is suppressed that the injection characteristics such as the weight and the flight speed of the ink ejected from the nozzle 75 fluctuate due to the thickening of the ink. Will be done. Therefore, the reliability of the printer 1 is improved. Further, in the printer 1, by sealing the nozzle surface of the recording head 3 with a cap 6'and sucking the ink, it is possible to reduce the amount of ink consumed in the maintenance operation of discharging the thickened ink from the nozzle 75. ..
Further, since one of the flow path constituent members of the flow path member 9 is the second flow path member 15 that also functions as the flow path isolation member, it is necessary to separately provide the flow path isolation member in addition to the flow path constituent member. The recording head 3 can be miniaturized. In addition, material costs can be reduced.
Then, in the present embodiment, the second flow path member 15 is joined to the first case 10 having a higher gas barrier property than the seal member 18, and the sealing space 12 is defined, so that the sealing space 12 is defined. Evaporation of the water content of the ink in the liquid flow path in the flow path member 9 arranged in the 12 is more reliably suppressed.

By the way, the present invention is not limited to the above-described embodiment, and various modifications can be made based on the description of the scope of claims.

FIG. 10 is a cross-sectional view of a main part around the positioning pin in the second embodiment. In the first embodiment, the positioning recess 29 into which the tip of the positioning pin 26 can be fitted into the second flow path member 15 that also functions as the flow path isolation member among the flow path constituent members of the flow path member 9. Although formed, thereby exemplifying a configuration in which the positioning pin 26 is arranged in the sealing space 12 in a state of being covered with the first flow path member 14, the filter substrate 16, and the second flow path member 15. Not limited to this. Similar to the first flow path member 14 and the filter substrate 16, the second flow path member 15 in the present embodiment is provided with a positioning hole 89 (corresponding to the insertion hole in the present invention) through which the positioning pin 26 can be inserted. It is opened in a state of penetrating in the thick direction. Then, the positioning pin 26 is inserted into the positioning holes 27, 28, 89 of these flow path constituent members, respectively, and the tip end portion thereof is outside the flow path member 9 (the first) in the positioning hole 89 of the second flow path member 15. It is exposed on the lower surface side of the flow path member 15 of 2. In the present embodiment, the tip of the positioning pin 26 exposed in the positioning hole 89 is sealed with a sealing material 90 such as an epoxy adhesive. As a result, the positioning pin 26 is arranged in the sealing space 12 in a state of being covered with the first flow path member 14, the filter substrate 16, the second flow path member 15, and the sealing material 90. Therefore, the sealing space 12 is prevented from communicating with the atmosphere through the positioning holes 27, 28, 89 through which the positioning pin 26 is inserted, and the positioning pin is maintained while ensuring the airtightness and liquidtightness of the sealing space 12. Positioning of the flow path constituent member by 26 becomes possible. The other configurations are the same as those in the first embodiment.

Further, in each of the above embodiments, the configuration in which the resistance passage in the air opening path is formed by the outer wall 51 of the seal member 18 being brought into close contact with the groove 41 formed in the second flow path member 15 is illustrated. However, the present invention is not limited to this, and for example, a resistance passage may be formed by joining the flow path constituent members to each other. In this case, for example, a groove similar to the groove 41 is formed in at least one of the flow path constituent members, and the other flow path constituent member is joined by an adhesive to seal the opening of the groove to draw a resistance passage. Can be done. According to this configuration, the resistance passage is formed by joining the flow path constituent members having a higher gas barrier property, so that the evaporation of water from the resistance passage is further reduced.

Further, as the flow path constituent members constituting the flow path member 9, the first flow path member 14, the filter substrate 16, and the second flow path member 15 have been exemplified in the above-described embodiment. Not limited. In short, it may be a configuration including at least one flow path constituent member and a flow path isolation member.

In the above description, the inkjet recording head 3 (head unit 13), which is a kind of liquid injection head, has been described as an example, but the present invention is also applicable to other liquid injection heads provided with a flow path member. Can be done. For example, a color material injection head used for manufacturing a color filter such as a liquid crystal display, an electrode material injection head used for forming electrodes of an organic EL (Electro Luminescence) display, a FED (surface emitting display), and a biochip (biochemical element). ), The present invention can also be applied to a bioorganic substance injection head or the like used for manufacturing.

1 ... Printer, 2 ... Recording medium, 3 ... Recording head, 4 ... Carriage, 5 ... Carriage moving mechanism, 6 ... Capping mechanism, 7 ... Ink cartridge, 8 ... FFC, 9 ... Flow path member, 10 ... First case , 11 ... second case, 12 ... sealing space, 13 ... head unit, 14 ... first flow path member, 15 ... second flow path member, 16 ... filter board, 17 ... circuit board, 18 ... seal Member, 19 ... Flow path connecting member, 20 ... Head cover, 21 ... Introduction needle substrate, 22 ... Introduction needle, 23 ... Side wall, 24 ... Filter chamber, 25 ... Filter, 26 ... Positioning pin, 27 ... Positioning hole, 28 ... Positioning Hole, 29 ... Positioning recess, 30 ... Fastening member, 31 ... Guide flow path, 32 ... Outlet port, 33 ... Supply flow path, 34 ... Communication port, 35 ... Flow path connection part, 36 ... Connection flow path, 37 ... Communication Holes, 38 ... 1st peripheral wall, 39 ... 2nd peripheral wall, 40 ... fitting part, 41 ... groove, 42 ... 1st through hole, 43 ... 2nd through hole, 44 ... open air path, 45 ... 1st Atmospheric communication passage, 46 ... 2nd atmospheric communication passage, 47 ... 3rd atmospheric communication passage, 48 ... Atmospheric opening, 49 ... Introduction part, 50 ... Introduction flow path, 51 ... Outer wall, 52 ... Flow path connection space, 54 ... Connector, 55 ... Flexible board, 56 ... Relief hole, 57 ... Relief hole, 59 ... Containment chamber, 60 ... Partition wall, 61 ... Board insertion port, 62 ... Opening, 64 ... Case flow path, 65 ... Head case, 66 ... Nozzle plate, 67 ... Communication board, 68 ... Compliance board, 69 ... Pressure chamber forming board, 70 ... Vibration plate, 71 ... Pietryl element, 72 ... Protective board, 73 ... Pressure chamber, 74 ... Nozzle communication path, 75 ... Nozzle , 76 ... Individual communication port, 77 ... Common liquid chamber, 78 ... Drive IC, 79 ... Storage space, 80 ... Compliance sheet, 81 ... Sheet support plate, 82 ... Board opening, 83 ... Compliance opening, 84 ... Compliance space , 85 ... Wiring space, 86 ... Storage space, 88 ... Through space, 89 ... Positioning hole, 90 ... Encapsulant

Claims (8)

A first case for accommodating a flow path member in which a liquid flow path is formed, and
A second case with a head unit and
A sealing member having a connecting portion that seals the liquid flow path on the first case side and the liquid flow path on the second case side and connects them in a liquid-tight manner.
A liquid injection head that injects a liquid from the flow path member from a nozzle of the head unit.
A flow path isolation member having a higher gas barrier property as compared with the seal member is arranged between the first case and the seal member.
The liquid injection head is characterized in that the flow path member is arranged in a sealing space defined in the first case by joining the flow path isolation member to the first case. The liquid injection head according to claim 1, wherein the first case has a high gas barrier property as compared with the sealing member. The sealing member has an outer wall along the outer periphery, and the connecting portion is arranged by bringing the outer wall into contact with the flow path isolating member and the constituent member on the second case side, respectively. The liquid injection head according to claim 1 or 2, wherein the space is sealed. The flow path isolation member has a groove extending along the outer circumference at a portion of the seal member that is in contact with the outer wall, and the outer wall is brought into contact with the portion to form a resistance passage.
The liquid injection head according to claim 3, wherein the resistance passage communicates with the sealing space and also with an open air passage connected to the atmosphere. The first case has a positioning pin that defines the placement position of the flow path member.
The flow path member has an insertion hole through which the positioning pin is inserted.
The flow path isolation member has a recess into which the tip of the positioning pin fits.
The positioning pin is inserted into the insertion hole and fitted into the recess, so that the positioning pin is arranged in the sealing space in a state of being covered with the flow path member and the flow path isolation member. The liquid injection head according to any one of claims 1 to 4. The first case has a positioning pin that defines the placement position of the flow path member.
The flow path member and the flow path isolation member have an insertion hole through which the positioning pin is inserted.
According to claim 1, the positioning pin is inserted into the insertion hole, and the tip portion exposed from the insertion hole is arranged in the sealing space in a state of being sealed by a sealing material. The liquid injection head according to any one of claims 4. The flow path member is configured by laminating a plurality of flow path constituent members.
The liquid injection head according to any one of claims 1 to 6, wherein one of the flow path constituent members is the flow path isolation member. A liquid injection device comprising the liquid injection head according to any one of claims 1 to 7.

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