JP2018103500A - Liquid discharge head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid discharge head which inhibits dew condensation of a circuit board while inhibiting evaporation of a liquid in a passage.SOLUTION: A liquid discharge head includes: a head body which discharges a liquid from a nozzle by driving a driving element; a circuit board including a circuit that generates a driving signal for driving the driving element; a first passage structure including a passage which supplies the liquid to the nozzle; a second passage structure including a passage which introduces the liquid to the passage of the first passage structure; and an elastic member disposed between a first space including the head body, the circuit board, and the first passage structure and a second space including the second passage structure. The elastic member has a cutout part which opens in the first space to communicate with the atmospheric air. The second space has airtightness higher than the first space.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a technique for discharging a liquid such as ink.

  In a liquid discharge head that discharges a liquid such as ink from a nozzle by driving a drive element, a circuit board including electronic components that drive the drive element is accommodated in a case member of the liquid discharge head. If liquid mist or the like enters such a liquid discharge head, there is a possibility that the liquid mist adheres to an electronic component and causes insulation failure. For this reason, for example, in the liquid discharge head of Patent Document 1, the outer surface is entirely covered so as to cover the joint so that liquid mist or the like does not enter from the joint between the introduction needle holder that holds the liquid introduction needle and the case member. A technique for sealing the inside of a liquid discharge head by winding an annular elastic protective member in close contact with the periphery is disclosed.

JP 2007-105926 A

  However, since a flow path structure including a flow path through which the liquid flows is accommodated in the liquid discharge head, the space in the liquid discharge head is sealed with an elastic protection member as in Patent Document 1. As a result, the humidity in the liquid discharge head becomes high, and there is a possibility that an electrical connection portion of the circuit board is dewed and insulation failure occurs. In this case, it is considered that the humidity can be reduced if the liquid discharge head is opened to the atmosphere. However, if the entire space in the liquid discharge head is communicated with the atmosphere, the moisture of the liquid in the flow path depends on the humidity. Since the liquid tends to evaporate, the liquid in the flow path may increase in viscosity, or bubbles mixed in the flow path may grow. In view of the above circumstances, an object of the present invention is to suppress dew condensation on a circuit board while suppressing evaporation of a liquid in a flow path.

  In order to solve the above problems, a liquid discharge head according to the present invention includes a head main body that discharges liquid from a nozzle by driving a drive element, and a circuit board that includes a circuit that generates a drive signal for driving the drive element. A first flow path structure including a flow path for supplying liquid to the nozzle, a second flow path structure including a flow path for introducing liquid into the flow path of the first flow path structure, and a head body And a first space including the circuit board and the first flow path structure, and an elastic member interposed between the second space including the second flow path structure, and the elastic member includes the first space. The second space has a higher airtightness than the first space. According to the above configuration, since the first space including the circuit board communicates with the atmosphere via the cutout portion of the elastic member, it is possible to suppress the humidity in the first space from being higher than the atmosphere. Therefore, it is possible to suppress the dew condensation on the circuit board that causes the insulation failure. On the other hand, since the second space including the second flow path structure has higher airtightness than the first space, the liquid in the flow path of the second flow path structure can be prevented from evaporating. Thus, according to this configuration, it is possible to suppress the condensation of the circuit board while suppressing the evaporation of the liquid in the flow path.

  In a preferred aspect of the present invention, the flow path of the second flow path structure includes a filter that filters the liquid flowing through the flow path. According to the above configuration, since the second space having the second flow path structure is hermetically sealed by the elastic member, the barrier property is enhanced, and it is difficult for air to enter from the outside. Even if the gas mixed in the liquid accumulates in the filter, the bubbles can be prevented from growing. Therefore, it is possible to suppress the liquid from becoming difficult to pass through the filter due to the growth of bubbles.

  In a preferred aspect of the present invention, the head body can be mounted on a carriage that reciprocates, and the elastic member has a first surface along a first direction in which the carriage reciprocates and a second surface that intersects the first direction. It has the 2nd surface along a direction, and a notch is formed in the 1st surface and is not formed in the 2nd surface. In the above configuration, the first surface of the elastic member is along the first direction in which the carriage reciprocates, whereas the second surface of the elastic member is along the second direction that intersects the first direction. . For this reason, the mist of the liquid that has risen without landing on the medium is less likely to enter the first surface than the second surface. Therefore, according to the present configuration, the cutout portion of the elastic member is formed on the first surface and is not formed on the second surface, so that it is difficult for liquid mist to enter the first space via the cutout portion. .

  In a preferred aspect of the present invention, the head body can be mounted on a carriage that reciprocates, and the elastic member has a first surface along a first direction in which the carriage reciprocates and a second surface that intersects the first direction. It has the 2nd surface along a direction, and a notch part is formed in the 1st surface and the 2nd surface, and the number of notch parts is larger in the 1st surface than the 2nd surface. In the above configuration, the cutout portion of the elastic member is formed on the first surface and the second surface, but the first surface has a larger number of cutout portions than the second surface. Since the number of notches is smaller than that of the first surface, it is possible to prevent liquid mist from entering the first space through the notches.

  In a preferred aspect of the present invention, the notch portion on the first surface has a larger area opening into the first space than the notch portion on the second surface. According to the above configuration, since the notch portion of the first surface has a larger area opening into the first space than the notch portion of the second surface, the second surface is more of the notch portion than the first surface. Since the cross-sectional area becomes small, it is possible to suppress the liquid mist from entering the first space through the cutout portion of the second surface.

  In a preferred aspect of the present invention, an air flow path that communicates the second space with the atmosphere is provided, and the air flow path has a larger flow path resistance than the cutout portion of the elastic member. According to the above configuration, since the air flow path that communicates the second space with the atmosphere is provided, it is possible to suppress the internal pressure fluctuation in the second air sea due to the temperature change. Since the air flow path of the second space has a flow path resistance larger than that of the cutout portion of the elastic member, it is possible to suppress a decrease in the airtightness of the second space, so that the second space can hold humidity. Therefore, according to this configuration, it is possible to suppress the internal pressure fluctuation due to the temperature change while suppressing the deterioration of the airtightness of the second space.

  In a preferred aspect of the present invention, the air flow path does not overlap the cutout portion of the elastic member in a plan view from the stacking direction of the elastic member. According to the above configuration, since the air flow path does not overlap with the cutout portion of the elastic member in a plan view from the stacking direction of the elastic member, when the elastic member is stacked on another member, Since it can suppress that the amount of crushing reduces, the adhesiveness of an elastic member and another member can be improved. Accordingly, it is possible to suppress a decrease in the sealing performance of the second space.

It is a block diagram of the liquid discharge apparatus which concerns on 1st Embodiment. It is an external appearance perspective view of a liquid discharge head. It is an exploded perspective view of a liquid discharge head. It is sectional drawing of a liquid discharge part. It is VV sectional drawing of FIG. It is a top view for demonstrating the structure of the downstream of a sealing member. It is a top view for demonstrating the structure of the upstream of a sealing member. It is a top view for demonstrating the structure of the downstream of the sealing member in 2nd Embodiment. It is a top view for demonstrating the structure of the upstream of the sealing member in 2nd Embodiment.

<First Embodiment>
FIG. 1 is a partial configuration diagram of a liquid ejection apparatus 10 according to the first embodiment of the present invention. The liquid ejection apparatus 10 according to the first embodiment is an ink jet printing apparatus that ejects ink, which is an example of a liquid, onto a medium 11 such as printing paper. A liquid ejection apparatus 10 illustrated in FIG. 1 includes a control device 12, a transport mechanism 14, a carriage 18, and a liquid ejection head 20. The control device 12 comprehensively controls each element of the liquid ejection device 10.

  The transport mechanism 14 transports the medium 11 in the Y direction (sub-scanning direction) under the control of the control device 12. The carriage 18 reciprocates in the X direction (main scanning direction) under the control of the control device 12. In parallel with the conveyance of the medium 11 and the reciprocation of the carriage 18, the liquid discharge head 20 discharges ink onto the medium 11, thereby forming a desired image on the surface of the medium 11. A direction perpendicular to the XY plane (a plane parallel to the surface of the medium 11) is hereinafter referred to as a Z direction. The ink ejection direction (vertical downward) of the liquid ejection head 20 corresponds to the Z direction. The X direction is a specific example of the first direction in which the carriage 18 reciprocates, and the Y direction is a specific example of the second direction that intersects (is orthogonal to) the X direction. The Z direction is a specific example of the stacking direction of seal members 25 described later.

  The carriage 18 is provided with a liquid storage portion (cartridge holder) 182 for storing a plurality of liquid containers (cartridges) C1 to C4 that separately store a plurality of types of ink. The ink is a liquid (color ink) containing a color material such as a pigment or a dye. For example, the ink is a total of four colors of cyan (C), magenta (M), yellow (Y), and black (K). It is also possible to include a resin material in the ink. The liquid containers C1 to C4 of the present embodiment contain cyan (C), magenta (M), yellow (Y), and black (K) inks, respectively. A liquid discharge head 20 is mounted below the liquid storage portion 182 of the carriage 18.

  The liquid discharge head 20 includes a plurality of liquid discharge units (head chips) 70. In this embodiment, the case where the four liquid discharge parts 70 are arranged so that it may line up along a X direction is illustrated. However, the arrangement of the four liquid discharge units 70 is not limited to the illustrated one, and may be arranged in a staggered shape or a staggered shape, for example. Moreover, the number of the liquid discharge parts 70 is not restricted to what was illustrated. Two nozzle rows are arranged in each of the liquid ejection units 70. Each nozzle row is a set of a plurality of nozzles N arranged linearly along the Y direction. The liquid discharge head 20 includes a flow path through which ink flows and a filter F provided in the middle of the flow path. The filter F filters the ink flowing through the flow path and collects foreign matters and bubbles mixed in the ink.

  FIG. 2 is an external perspective view of the liquid discharge head 20, and FIG. 3 is an exploded perspective view of the liquid discharge head 20. FIG. 4 is a cross-sectional view of any one liquid ejection unit 70. 5 is a cross-sectional view taken along the line VV in FIG. 3 (a cross section parallel to the YZ plane). As shown in FIGS. 2 and 3, the liquid ejection head 20 in the present embodiment includes a flow path structure 202 and a head body 204. The head main body 204 includes four liquid ejection units 70. The flow path structure 202 supplies ink (C, M, Y, K) from the liquid containers C 1 to C 4 to the liquid ejection units 70 of the head body 204.

  As shown in FIG. 4, the liquid ejection unit 70 has a pressure chamber forming substrate 72 and a vibration plate 73 stacked on one surface of a flow path forming substrate 71 and a nozzle plate 74 and a compliance unit 75 installed on the other surface. The head chip is included. The plurality of nozzles N are formed on the nozzle plate 74. In addition, since the structure corresponding to each row of the nozzles N is formed in one liquid ejecting unit 70 in a substantially line symmetrical manner, the following will focus on one row of the nozzles N for convenience. The structure will be described.

  The flow path forming substrate 71 is a flat plate material that forms a flow path of ink. In the flow path forming substrate 71 of the present embodiment, an opening 712, a supply flow path 714, and a communication flow path 716 are formed. The supply channel 714 and the communication channel 716 are formed for each nozzle N, and the opening 712 is continuous over the plurality of nozzles N. The pressure chamber forming substrate 72 is a flat plate material in which a plurality of openings 722 corresponding to different nozzles N are formed. The flow path forming substrate 71 and the pressure chamber forming substrate 72 are formed of, for example, a silicon single crystal substrate.

  The compliance unit 75 in FIG. 4 is a mechanism that suppresses (absorbs) pressure fluctuations in the flow path of the liquid ejection unit 70, and includes a sealing plate 752 and a support body 754. The sealing plate 752 is a flexible film-like member, and the support 754 flows the sealing plate 752 so that the opening 712 and each supply channel 714 of the channel forming substrate 71 are closed. It fixes to the path | route formation board | substrate 71. FIG.

  A diaphragm 73 is installed on the surface of the pressure chamber forming substrate 72 in FIG. 4 opposite to the flow path forming substrate 71. The vibration plate 73 is a plate-like member that can elastically vibrate, and is configured by stacking an elastic film formed of an elastic material such as silicon oxide and an insulating film formed of an insulating material such as zirconium oxide. Is done. The diaphragm 73 and the flow path forming substrate 71 are opposed to each other with an interval inside each opening 722 formed in the pressure chamber forming substrate 72. The space sandwiched between the flow path forming substrate 71 and the diaphragm 73 inside each opening 722 functions as a pressure chamber (cavity) C that applies pressure to the ink. In the present embodiment, two rows of the plurality of pressure chambers C arranged along the Y direction are arranged along the X direction.

  A plurality of piezoelectric elements 732 corresponding to different nozzles N are formed on the surface of the diaphragm 73 opposite to the pressure chamber forming substrate 72. Each piezoelectric element 732 is a laminated body in which a piezoelectric body is interposed between electrodes facing each other. As the drive signal is supplied, the piezoelectric element 732 vibrates together with the vibration plate 73, whereby the pressure in the pressure chamber C varies and the ink in the pressure chamber C is ejected from the nozzle N. Accordingly, the piezoelectric element 732 functions as a driving element that generates a driving force for ejecting ink from the nozzle N. Each piezoelectric element 732 is sealed and protected by a protective plate 76 fixed to the vibration plate 73.

  As shown in FIG. 4, a support body 77 is fixed to the flow path forming substrate 71 and the protection plate 76. The support body 77 is integrally formed by molding a resin material, for example. In the support body 77 of this embodiment, a space 772 that forms a liquid storage chamber (reservoir) R together with the opening 712 of the flow path forming substrate 71 and a supply port 774 that communicates with the liquid storage chamber R are formed. In the liquid storage chamber R, the ink introduced from the supply port 774 is stored. The ink stored in the liquid storage chamber R is distributed and filled into the pressure chambers C by the plurality of supply channels 714, and passes from the pressure chambers C to the communication channels 716 and the nozzles N to the outside (medium 11 side). ).

  The end of the individual wiring board 78 is joined to the diaphragm 73. The individual wiring board 78 is a flexible wiring board on which wiring for transmitting a drive signal and a power supply voltage to each piezoelectric element 732 is formed. One individual wiring board 78 is provided for each of the four liquid ejection units 70. Each individual wiring board 78 is connected to a circuit board 26 described later.

  As shown in FIGS. 2 and 3, the flow path structure 202 is formed by housing each component in a case member made up of an upper case member 22 and a lower case member 23. The upper case member 22 and the lower case member 23 are integrally formed by, for example, injection molding of a resin material. The upper case member 22 and the lower case member 23 are fixed with a plurality of screws 24.

  As shown in FIGS. 3 and 5, a space S <b> 1 is formed below the upper case member 22. A space S2 is formed above the lower case member 23, and a space S3 is formed below the lower case member 23. The space S1 of the upper case member 22 communicates with the space S2 of the lower case member 23.

  In the space S2 of the lower case member 23, a sealing member 25 as a sealing member, a circuit board 26, and a first flow path structure G1 are sequentially stacked from above. The space S3 of the lower case member 23 accommodates the plurality of liquid discharge portions 70 described above, and the space S3 of the lower case member 23 is closed from below by the fixing plate 29. The second flow path structure G2 is accommodated in the space S1 of the upper case member 22.

  The second flow path structure G2 includes flow path members 221, 222, and 223 that are stacked. In the flow path members 221, 222, and 223, ink flow paths (not shown) are provided. The filter F described above is provided in the middle of the flow path in the flow path member 222. In FIG. 3, the flow path members 221, 222, and 223 are omitted.

  The circuit board 26 is a board that relays drive signals and other control signals sent from the control device 12. The circuit board 26 is formed with a terminal portion 262 that is electrically connected to the individual wiring board 78 of each liquid ejection unit 70, and a connector 264 for connecting to the control device 12, other electronic components, and the like. Implemented. The terminal portion 262 and the connector 264 are electrical joints. In the circuit board 26 of the present embodiment, four terminal portions 262 corresponding to the individual wiring boards 78 of the four liquid ejection portions 70 are formed on the upper surface (surface on the negative side in the Z direction) of the circuit substrate 26. The connector 264 is connected to a wiring member such as an FFC (flexible flat cable), and the circuit board 26 receives a drive signal from the control device 12 via the FFC. The connector 264 of the circuit board 26 according to the present embodiment is disposed so as to be exposed from the opening of the side wall 234 on both the positive side and the negative side in the X direction of the side wall 234 of the lower case member 23.

  The first flow path structure G1 is a flat structure in which an ink flow path is formed. The first channel structure G1 may be a stack of a plurality of channel members. The lower case member 23 is formed with a plurality of flow paths 232 protruding upward, and the first flow path structure G1 is formed with a plurality of flow paths 272 protruding upward. Each flow path 232 passes through the first flow path structure G1 and the through hole formed in the circuit board 26, and communicates with the flow paths of the flow path members 221, 222, and 223 through the through hole 252 of the seal member 25. Has been. Each flow path 272 passes through a through hole formed in the circuit board 26 and communicates with the flow paths of the flow path members 221, 222, and 223 through the through hole 252 of the seal member 25. Ink is introduced into each liquid ejection section 70 via each flow path 232, 272.

  At the lower end of the lower case member 23, a cylindrical frame body 236 that forms a space for accommodating each liquid ejection part 70 is formed to protrude downward (positive side in the Z direction). In the present embodiment, the four liquid ejection units 70 are arranged in parallel in the frame body 236 along the X direction (main scanning direction) perpendicular to the conveyance direction of the medium 11. Each piezoelectric element 732 of each liquid ejection unit 70 vibrates in accordance with a drive signal supplied from the control device 12 via the circuit board 26 and the individual wiring board 78. The ink filled in the pressure chamber C is ejected from each nozzle N of the nozzle plate 74 by vibrating the piezoelectric element 732 to change the pressure in the pressure chamber C.

  The fixed plate 29 is a flat member. In the fixed plate 29, four openings 292 each having a shape corresponding to the nozzle plate 74 of each liquid discharge unit 70 (a rectangular shape elongated in the Y direction) are formed for each liquid discharge unit 70. In a state where the nozzle plate 74 is positioned inside the opening 292, each liquid ejection unit 70 is fixed to the upper surface (surface on the negative side in the Z direction) of the fixing plate 29 with an adhesive, for example. Thereby, the nozzles N of each nozzle row are arranged in the opening 292, respectively. Note that the liquid ejection head 20 does not have to be provided with the fixing plate 29.

  A relay unit 40 that relays ink from the liquid containers C1 to C4 to the flow path in the upper case member 22 is provided on the upper surface of the upper case member 22 (the surface opposite to the ejection surface A). The relay unit 40 includes a plurality of ink introduction needles (relay members) 42 erected on the upper surface of the upper case member 22 and a surrounding wall 44 that surrounds the periphery of the ink introduction needles 42. In the present embodiment, a total of four ink introduction needles 42 corresponding to the four color liquid containers C1 to C4 are juxtaposed along the X direction (main scanning direction) perpendicular to the conveyance direction of the medium 11. Yes.

  The ink introduction needle 42 is a hollow needle-like member inserted into the liquid containers C1 to C4. An introduction hole 43 is opened at the tip of the ink introduction needle 42. The introduction hole 43 communicates with the flow paths in the flow path members 221, 222, and 223. The introduction hole 43 allows the ink in the liquid containers C1 to C4 to pass through the flow paths in the flow path members 221, 222, and 223 and the flow path 232 of the lower case member 23 and the 272 of the first flow path structure G1. Are introduced into each liquid ejection unit 70.

  The relay unit 40 is divided into a total of four cartridge placement areas 46 arranged in the X direction by ribs 45 provided on the inner side of the surrounding wall 44, and one ink introduction needle 42 is provided in each of these cartridge placement areas 46. It is erected. In addition, the liquid containers C1 to C4 are attached to the cartridge arrangement regions 46, respectively.

(Configuration of seal member)
The seal member 25 shown in FIG. 3 and FIG. 5 includes a downstream annular seal portion 253 having a thickness increased downward (downstream) from the peripheral edge and an upstream annular seal portion 255 increased in thickness above the peripheral edge (upstream side). It is a plate-shaped elastic member which has. As shown in FIG. 5, the seal member 25 includes a first space SI1 including the head body 204, the circuit board 26, and the first flow path structure G1, and a second space SI2 including the second flow path structure G2. Intervene between. The seal member 25 has a notch portion 256 that opens into the first space SI1 and communicates with the atmosphere, and hermetically seals the second space SI2.

  The first space SI1 is formed by joining the head main body 204 (liquid ejection unit 70), the circuit board 26, and the first flow path structure G1 on the downstream side (the positive side in the Z direction) from the seal member 25. An internal space that is outside the flow path. The downstream side annular seal portion 253 of the seal member 25 is in close contact with the circuit board 26. The downstream annular seal portion 253 has a protrusion 254 on the contact surface with the circuit board 26 (the positive side surface in the Z direction). By being pressed against the circuit board 26, the protrusion 254 is crushed without being fixed by an adhesive or the like, and the downstream-side annular seal part 253 of the seal member 25 is in close contact with the circuit board 26. Thus, the space inside the downstream annular seal portion 253 formed by the downstream annular seal portion 253 of the seal member 25 being in close contact with the circuit board 26 becomes a part of the first space SI1.

  The second space SI2 is an internal space formed by joining the flow path members 221, 222, and 223 constituting the second flow path structure G2 on the upstream side of the seal member 25, and is outside the flow path. It is space. The upstream annular seal portion 255 of the seal member 25 is in close contact with the flow path member 223 of the second flow path structure G2. The upstream annular seal portion 255 is pressed against the flow path member 223 with the contact surface with the flow path member 223 (the negative side surface in the Z direction), so that the flow path member is not fixed with an adhesive or the like. Close contact with H.223. Thus, the space inside the upstream side annular seal part 255 formed so that the upstream side annular seal part 255 of the seal member 25 is in close contact with the flow path member 223 becomes a part of the second space SI2.

  By the way, if both the first space SI1 and the second space SI2 are sealed with the sealing member 25, the humidity in the liquid discharge head 20 becomes high, and the electric joint portion (the terminal portion 262 and the terminal portion 262) of the circuit board 26 increases. Connector 264 and the like) may condense and cause insulation failure. In this case, it is considered that the humidity can be reduced if the liquid ejection head 20 is opened to the atmosphere. However, if both the first space SI1 and the second space SI2 in the liquid ejection head 20 are communicated with the atmosphere, Depending on the humidity, the moisture in the ink in the flow path is likely to evaporate, so that there is a risk that the ink in the flow path will thicken or bubbles captured by the filter F will grow.

  Therefore, as shown in FIG. 3, the seal member 25 of the first embodiment has a cutout portion 256 that opens into the first space SI1 and communicates with the atmosphere, and hermetically seals the second space SI2. As shown in FIG. 5, the notch 256 communicates the first space SI <b> 1 inside the seal member 25 with the space SI <b> 3 outside the seal member 25. The space SI <b> 3 passes through the second flow path structure G <b> 2 and the upper case member 22 and communicates with a through hole 50 that opens in the upper case member 22. Accordingly, the first space SI1 inside the seal member 25 communicates with the atmosphere via the space SI3 and the through hole 50.

  According to such a configuration, the first space SI1 including the circuit board 26 communicates with the atmosphere via the cutout portion 256 of the seal member 25, so that the first space SI1 has a higher humidity than the atmosphere. Can be suppressed. Therefore, it is possible to suppress dew condensation at the electrical joint portion of the circuit board 26 that causes the insulation failure. On the other hand, since the second space SI2 including the second flow path structure G2 is hermetically sealed by the seal member 25, it is possible to suppress evaporation of ink moisture in the flow path of the second flow path structure G2. As described above, according to this embodiment, it is possible to suppress the condensation of the circuit board 26 while suppressing the evaporation of the moisture of the ink in the flow path.

  Hereinafter, a specific configuration example of the seal member 25 of the first embodiment will be described. 6 and 7 are plan views showing the configuration of the seal member 25. FIG. FIG. 6 is a view for explaining the configuration of the downstream side of the seal member 25, and is a view of the seal member 25 as viewed from below (the direction from the positive side to the negative side in the Z direction). FIG. 7 is a view for explaining the configuration of the upstream side of the seal member 25, and is a view of the seal member 25 as viewed from above (from the negative side to the positive side in the Z direction).

  As shown in FIG. 6, the downstream side of the seal member 25 is formed with a plurality of notches 256 spaced apart from the peripheral downstream annular seal portion 253. The downstream annular seal portion 253 is formed with a protrusion 254 that protrudes more to the positive side in the Z direction than the notch 256 at a portion where the notch 256 is not formed. The first space SI1 inside the downstream annular seal portion 253 communicates outside the downstream annular seal portion 253 through the notch 256. As shown in FIG. 5, the space SI3 outside the downstream-side annular seal portion 253 communicates with the atmosphere via the through hole 50, so the first space SI1 communicates with the atmosphere via the notch 256. . In addition, according to the structure of FIG. 6, since the several notch part 256 is formed, compared with the case where the notch part 256 per one is made small, compared with the case where the large notch part 256 is formed, the downstream side The portion where the annular seal portion 253 contacts the circuit board 26 can be increased. According to this configuration, it is possible to suppress a decrease in the adhesion between the downstream annular seal portion 253 and the circuit board 26 and the adhesion between the upstream annular seal portion 255 and the second flow path structure G2.

  The seal member 25 has a first surface 25a along the X direction in which the carriage 18 reciprocates, and a second surface 25b along the Y direction intersecting the X direction. The first surface 25a is a positive side surface and a negative side surface in the Y direction. The second surface 25b is a positive side surface and a negative side surface in the X direction. The notches 256 are formed on both the first surface 25a and the second surface 25b of the downstream annular seal portion 253, and the first surface 25a has more notches 256 than the second surface 25b. In the configuration of FIG. 6, three cutout portions 256 are formed on each of the positive and negative first surfaces 25a in the Y direction, and one cutout portion is formed on each of the positive and negative second surfaces 25b in the X direction. A portion 256 is formed.

  The first surface 25a of the seal member 25 is along the X direction in which the carriage 18 reciprocates, whereas the second surface 25b is along the Y direction intersecting with the X direction. Therefore, the first surface 25a is less likely to receive ink mist that has risen without landing on the medium 11 than the second surface 25b. Therefore, although the notches 256 of this configuration are formed on both the first surface 25a and the second surface 25b, the first surface 25a has more notches 256 than the second surface 25b. Since the number of the notch portions 256 is smaller in the second surface 25b than in the first surface 25a, it is possible to suppress the ink mist from entering the first space SI1 through the notch portion 256.

  Further, the cutout portion 256 of the first surface 25a has a larger area opening into the first space SI1 than the cutout portion 256 of the second surface 25b. According to such a configuration, the second surface 25b is smaller in cross-sectional area of the notch portion 256 than the first surface 25a, so that ink mist enters the first space SI1 through the notch portion 256. Can be suppressed.

  On the other hand, as shown in FIG. 5, the second space SI2 is hermetically sealed on the upstream side of the seal member 25 because the upstream annular seal portion 255 at the peripheral edge is in close contact with the flow path member 223 of the second flow path structure G2. Is done. As shown in FIGS. 3 and 7, the upstream annular seal portion 255 of the seal member 25 may be provided with an air flow path 257 that allows the second space SI <b> 2 to communicate with the atmosphere. By forming the air flow path 257, the internal pressure fluctuation in the second space SI2 due to the temperature change can be suppressed. However, the air flow path 257 is configured to have a flow path resistance larger than that of the notch portion 256. Specifically, two long air flow paths 257 like a serpentine are formed in the upstream side annular seal portion 255. A communication passage 258 communicating with the second space SI2 inside the upstream annular seal portion 255 is formed at one end of each air flow path 257, and the upstream annular seal portion 255 is formed at the other end. A communication path 259 communicating with the outer space SI3 is formed. According to such an air flow path 257, the flow path resistance is increased, so that a decrease in airtightness between the seal member 25 and the second space SI2 can be suppressed. That is, the second space SI2 can have higher airtightness than the first space SI1 by the upstream annular seal portion 255. Accordingly, the second space SI2 can maintain humidity. Thus, according to the present embodiment, it is possible to suppress the internal pressure fluctuation of the second space SI2 due to the temperature change while suppressing the deterioration of the airtightness of the second space SI2.

  In the first embodiment, the case where the two air flow paths 257 are formed in the upstream annular seal portion 255 is illustrated, but the number of the air flow paths 257 may be one. Further, the air flow path 257 may be provided in the direction of the flow path member 223 without being formed in the seal member 25. Specifically, an air flow path 257 is provided in a portion of the flow path member 223 that contacts the upstream annular seal portion 255. Even if comprised in this way, the internal pressure fluctuation | variation in 2nd space SI2 by a temperature change can be suppressed.

  Further, the second space SI2 having the second flow path structure G2 has a higher airtightness than the first space SI1 by the seal member 25, so that the barrier property is enhanced and it is difficult for air to enter from the outside. Furthermore, even if the gas mixed in the ink accumulates in the filter F, the bubbles can be prevented from growing. Therefore, it is possible to suppress the ink from becoming difficult to pass through the filter F due to the growth of bubbles.

Second Embodiment
A second embodiment of the present invention will be described. In the following exemplary embodiments, elements having the same functions and functions as those of the first embodiment are diverted using the same reference numerals used in the description of the first embodiment, and detailed descriptions thereof are appropriately omitted. 8 and 9 are plan views showing the configuration of the seal member 25 in the second embodiment. FIG. 8 is a view for explaining the configuration of the downstream side of the seal member 25, and is a view of the seal member 25 as viewed from below (the direction from the positive side to the negative side in the Z direction). FIG. 9 is a view for explaining the configuration of the upstream side of the seal member 25, and is a view of the seal member 25 as viewed from above (from the negative side to the positive side in the Z direction).

  As shown in FIG. 8, on the downstream side of the seal member 25 of the second embodiment, a plurality of notches 256 are formed on the first surface 25a of the downstream annular seal portion 253, and the notches 256 are formed on the second surface 25b. Is not formed. According to such a configuration, the notch portion 256 is not formed in the second surface 25b where liquid mist easily enters due to the reciprocating movement of the carriage 18, so that the notch portion 256 is also formed in the second surface 25b. Thus, the effect of making it difficult for liquid mist to enter the first space SI1 can be enhanced.

  As shown in FIG. 9, in a plan view from the stacking direction (Z direction) of the seal member 25, the two air flow paths 257 formed in the upstream annular seal portion 255 of the seal member 25 of the second embodiment are: It does not overlap with the notch 256 of the seal member 25. According to such a configuration, when the seal member 25 is stacked on and closely contacted with the flow path member 223, it is possible to suppress a reduction in the amount of crushing of the seal member 25 in the notch portion 256, and thus the seal member 25 and the flow member Adhesiveness with the road member 223 can be improved. Therefore, it is possible to suppress a decrease in the sealing performance of the second space SI2.

  In addition, you may make it provide the air flow path 257 of 2nd Embodiment in the direction of the flow path member 223, without forming in the sealing member 25. FIG. Specifically, an air flow path 257 is provided in a portion of the flow path member 223 that contacts the upstream annular seal portion 255. Even if comprised in this way, the internal pressure fluctuation | variation in 2nd space SI2 by a temperature change can be suppressed.

<Modification>
Each embodiment illustrated above can be variously modified. Specific modifications are exemplified below. Two or more aspects arbitrarily selected from the following examples can be appropriately combined as long as they do not contradict each other.

(1) In the above-described embodiment, the serial head that reciprocally reciprocates the carriage 18 on which the liquid discharge head 20 is mounted along the X direction is exemplified. However, the line head in which the liquid discharge head 20 is arranged over the entire width of the medium 11. The present invention can also be applied to.

(2) In the above-described embodiment, the piezoelectric liquid ejection head 20 using a piezoelectric element is exemplified as a driving element for applying mechanical vibration to the pressure chamber. However, bubbles are generated inside the pressure chamber by heating. It is also possible to employ a thermal type liquid discharge head using a heating element.

(3) The liquid ejecting apparatus exemplified in the above-described embodiment can be employed in various apparatuses such as a facsimile apparatus and a copying machine in addition to an apparatus dedicated to printing. However, the use of the liquid ejection apparatus of the present invention is not limited to printing. For example, a liquid discharge device that discharges a solution of a color material is used as a manufacturing device that forms a color filter of a liquid crystal display device. In addition, a liquid discharge apparatus that discharges a solution of a conductive material is used as a manufacturing apparatus that forms wiring and electrodes of a wiring board.

DESCRIPTION OF SYMBOLS 10 ... Liquid discharge apparatus, 11 ... Medium, 12 ... Control apparatus, 14 ... Conveyance mechanism, 18 ... Carriage, 182 ... Liquid accommodating part, 20 ... Liquid discharge head, 202 ... Flow path structure, 204 ... Head main body, 22 ... Upper case member, 221, 222, 223 ... flow path member, 23 ... lower case member, 232 ... flow path, 234 ... side wall, 236 ... frame, 24 ... screw, 25 ... seal member, 25a ... first surface, 25b ... second surface, 252 ... through hole, 253 ... downstream annular seal, 254 ... projection, 255 ... upstream annular seal, 256 ... notch, 257 ... air channel, 258 ... communication channel, 259 ... Communicating path, 26 ... Circuit board, 262 ... Terminal part, 264 ... Connector, 272 ... Flow path, 29 ... Fixing plate, 292 ... Opening part, 40 ... Relay part, 42 ... Ink introduction needle, 43 ... Introduction hole, 44 ... Go wall, 45 ... , 46 ... cartridge arrangement region, 50 ... through-hole, 70 ... liquid ejection part, 71 ... channel forming substrate, 712 ... opening, 714 ... supply channel, 716 ... communication channel, 72 ... pressure chamber forming substrate, 722 ... Opening part 73 ... Vibration plate 732 ... Piezoelectric element 74 ... Nozzle plate 75 ... Compliance part 752 ... Sealing plate 754 ... Support body 76 ... Protection plate 77 ... Support body 772 ... Space 774 DESCRIPTION OF SYMBOLS ... Supply port, 78 ... Individual wiring board, A ... Discharge surface, C ... Pressure chamber, C1-C4 ... Liquid container, F ... Filter, G1 ... First flow path structure, G2 ... Second flow path structure, N ... Nozzle, R ... Liquid reservoir, SI1 ... first space, SI2 ... second space, SI3 ... space, S1, S2, S3 ... space.

Claims (7)

A head body that discharges liquid from the nozzle by driving the drive element;
A circuit board comprising a circuit for generating a drive signal for driving the drive element;
A first flow path structure including a flow path for supplying the liquid to the nozzle;
A second flow path structure including a flow path for introducing the liquid into the flow path of the first flow path structure;
A first space including the head main body, the circuit board, and the first flow path structure; and an elastic member interposed between the second space including the second flow path structure;
The elastic member has a notch that opens into the first space and communicates with the atmosphere,
The liquid ejection head, wherein the second space has higher airtightness than the first space. The liquid ejection head according to claim 1, wherein the flow path of the second flow path structure includes a filter that filters the liquid flowing through the flow path. The head body can be mounted on a reciprocating carriage;
The elastic member has a first surface along a first direction in which the carriage reciprocates and a second surface along a second direction intersecting the first direction,
The liquid ejection head according to claim 1, wherein the notch is formed on the first surface and is not formed on the second surface. The head body can be mounted on a reciprocating carriage;
The elastic member has a first surface along a first direction in which the carriage reciprocates and a second surface along a second direction intersecting the first direction,
The notch is formed in the first surface and the second surface,
3. The liquid ejection head according to claim 1, wherein the first surface has more notches than the second surface. 4. The liquid discharge head according to claim 4, wherein the cutout portion of the first surface has a larger area opening into the first space than the cutout portion of the second surface. An air flow path for communicating the second space with the atmosphere;
The liquid discharge head according to claim 1, wherein the air flow path has a larger flow path resistance than a cutout portion of the elastic member. The liquid discharge head according to claim 6, wherein the air flow path does not overlap with the cutout portion of the elastic member in a plan view from the stacking direction of the elastic member.

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