JP4466825B2 - Inkjet printer head - Google Patents

Description

  The present invention relates to a configuration of an ink jet recording apparatus, and more particularly to a configuration of an ink jet printer head in which a front head unit and an ink flow path forming member are connected.

  2. Description of the Related Art Conventionally, in an ink jet printer that records by discharging ink droplets from nozzles onto a recording medium such as paper based on an input signal, a member including the nozzles is unitized and a front head unit is provided on a surface facing the recording medium. It is known to install. For example, a stacked front head unit disclosed in Patent Document 1 includes a plate having a large number of nozzles arranged in a row on the front surface, a plurality of plates forming an ink flow path, and vibration for ink ejection. The front head unit is fixed to an ink flow path forming member (referred to as a head case in Patent Document 1) for supplying ink thereto by an adhesive. ing.

  On the adhesive surface between the front head unit and the ink flow path forming member, the ink supply port of the front head unit and the outlet portion of the ink flow path forming member are aligned, so that the applied adhesive is supplied to the ink supply. In many cases, the ink flows into the mouth and obstructs the supply of ink from the ink flow path forming member. In order to avoid this, in Patent Document 1, an edge that protrudes and contacts the opening end surface of the ink supply port is provided around the outlet portion of the ink flow path forming member, and the adhesive flows into the ink supply port. I try to prevent it. The front head unit and the ink flow path forming member are bonded and fixed in a wide range except for the ink supply port.

  However, generally, the front head unit is made of metal, while the ink flow path forming member is often made of synthetic resin, and the linear expansion coefficient of the synthetic resin and the metal is greatly different. For this reason, there has been a problem that peeling occurs between the front head unit and the ink flow path forming member due to temperature changes in the environment during long-term use, and ink leakage is likely to occur.

  In order to prevent ink leakage, an elastic seal member is generally inserted between the ink supply port of the front head unit and the ink outlet portion of the ink flow path forming member, but the front head unit is made of metal. Although it is a laminated structure, since it is thin as a whole, there is a problem that the front head unit is warped by a reaction force compressing the elastic seal member, and the directions of a large number of nozzles are not aligned.

When the configuration described in Patent Document 2 is used, the front head unit can be fixed without being deformed. In this structure, a sleeve is protruded from the ink supply port of the front head unit, an O-ring is inserted into the sleeve, and an O-ring is formed by a backup member disposed between the front head unit and the ink flow path forming member. At the same time as pressing against the ink flow path forming member, the O-ring is brought into close contact with the outer periphery of the sleeve. This prevents the reaction force due to the compression of the O-ring from acting on the front head unit.
JP-A-8-276586 (see FIG. 5) JP 2003-145791 A (see FIG. 10)

  In the configuration of the above-described Patent Document 2, members such as an O-ring and a sleeve are added to connect the front head unit and the ink flow path forming member. In order to prevent deformation, a backup member had to be added. As a result, there has been a problem that the number of parts and man-hours are increased and the manufacturing cost is increased.

  Further, in the configuration of Patent Document 2, an adhesive is used when a sleeve is protruded from the ink supply port of the front head unit. For this reason, as in the prior art, the adhesive flows into the ink supply port, and there is a problem that the ink flow is likely to be hindered.

  SUMMARY OF THE INVENTION It is an object of the present invention to provide an ink jet printer head that solves the above-described problems and prevents the deformation of the front head unit, eliminates the disadvantages caused by the adhesive, and stabilizes the ink ejection characteristics. Is.

In order to achieve the above object, an ink jet printer head according to a first aspect of the present invention includes a front head unit having a plurality of nozzles arranged in a line on the front surface and an ink supply port on the back surface, and the front head. An ink flow path forming member that supplies ink to the ink supply port of the unit , wherein the ink flow path forming member is formed by a partition wall and a flexible film and stores ink. A damper chamber and an ink outlet through which the ink flows out, and the front head unit includes: a cavity unit including the nozzle; and a piezoelectric actuator laminated and bonded to the back surface of the cavity unit. The front head unit has a frame-shaped reinforcing frame on the back surface. The interposed therebetween, is fixed to the ink flow path forming member, the reinforcing frame is made of metal, and said formed rigid greater than the cavity unit, wherein the reinforcing frame, the ink supply in the front head unit at positions corresponding to the mouth, the ink passage hole for connecting the ink outlet and the ink supply port in the ink flow path forming member is bored, between the ink flow path forming member and the reinforcing frame , the elastic sealing member surrounds the periphery of the ink passage hole of the reinforcing frame is characterized in that it is arranged in a compressed state.

According to a second aspect of the present invention, in the ink jet printer head according to the first aspect, the front head unit and the reinforcing frame are bonded with a sheet-like adhesive .

According to a third aspect of the present invention, in the inkjet printer head according to the first or second aspect, the front head unit is laminated and adhered to the cavity unit, the piezoelectric actuator, and a back surface of the piezoelectric actuator. A flexible flat cable, and the reinforcing frame is bonded to the back surface of the cavity unit by exposing the piezoelectric actuator and the flexible flat cable from within the frame, and the sheet-like adhesive surrounds the piezoelectric actuator. It has the shape which encloses continuously .

According to a fourth aspect of the present invention, in the inkjet printer head according to the second or third aspect , the sheet-like adhesive has a Young's modulus of 1-1000 MPa, a melting point of 80-180 ° C., and a reinforcement with the front head unit. The thickness after adhering the frame is 5 to 100 μm, and the adhesive strength is 10 N or more .

According to a fifth aspect of the present invention, in the ink jet printer head according to any of the second to fourth aspects, the ink flow path forming member is made of resin, and the ink flow path forming member is attached to the reinforcing frame. It is screwed, and the reinforcing frame and the front head unit are bonded with a sheet-like adhesive .

According to a sixth aspect of the present invention, in the ink jet printer head according to the fifth aspect , the ink flow path forming member side is screwed to the reinforcing frame .

  According to the first aspect of the present invention, the front head unit is fixed to the ink flow path forming member with the reinforcing frame having the ink passage hole interposed therebetween. Even if a pressing force is applied at the time of fixing, the pressing force can be supported by the reinforcing frame and does not work directly on the front head unit alone. Therefore, deformation that occurs in the front head unit can be prevented.

According to the first aspect of the invention, since the reinforcing frame is made of metal, the rigidity of the reinforcing frame is high, and the rigidity of the front head unit to which the reinforcing frame is attached is also increased.

Further, according to the first aspect of the present invention, the ink flow path forming member is formed of a partition wall and a flexible film, and a damper chamber that stores ink, and an ink that flows out of the ink through the damper chamber. An ink passage hole that connects the ink outlet and the ink supply port of the ink flow path forming member at a position corresponding to the ink supply port of the front head unit. Since the pierced and elastic sealing member is disposed between the reinforcing frame and the ink flow path forming member in a compressed state, the sealing performance is improved. As a result, ink is supplied without leakage from the ink flow path forming member to the ink supply port of the front head unit.

According to the invention described in claim 2 , since a sheet-like adhesive is used, unevenness due to coating, variation in the thickness of the adhesive layer, protrusion of the adhesive, and the like are greatly reduced as compared to a liquid adhesive. Can do. In addition, since the sheet-like adhesive is easy to use such as lifetime and curing time, it also has an effect that the process can be facilitated.

According to the invention of claim 3 , since the sheet-like adhesive that exhibits a sealing effect at the interface between the reinforcing frame and the cavity unit continuously surrounds the periphery of the piezoelectric actuator, the piezoelectric actuator is made of the sheet-like adhesive. It will be located in the enclosed closed region, and will surely prevent ink from entering the piezoelectric actuator. As a result, it is possible to prevent the occurrence of inconveniences such as an electrical short circuit of the electrodes of the piezoelectric actuator due to the ink.

According to the invention described in claim 4 , among various sheet-like adhesives, the Young's modulus is 1-1000 MPa, the melting point is 80-180 ° C., and the thickness after bonding the front head unit and the reinforcing frame is By selecting a sheet-like adhesive having 5 to 100 μm and an adhesive strength of 10 N or more, the sheet-like adhesive can absorb vibration propagation generated between the nozzle rows of the front head unit, and simultaneously between different nozzle rows. Crosstalk during discharge can be prevented. In addition, since the thickness of the sheet-like adhesive is adjusted by pressing while being softened by heating, the sheet-like adhesive absorbs waviness (distortion) of flatness due to the finishing accuracy of the reinforcing frame and can be corrected as a whole. It becomes possible.

  Next, an embodiment embodying the present invention will be described. As shown in FIG. 1, an ink jet printer 100 includes a recording mechanism unit 2 that performs recording by ejecting ink onto a sheet P that is a recording medium and is included in a main body frame 1, and a recording head unit 3 in the recording mechanism unit 2. A maintenance unit 4 that performs maintenance processing and an ink tank 5 that stores ink to be supplied to the recording head unit 3 that is fixedly disposed in the main body frame 1 are configured.

  A plurality of ink tanks 5 for full-color recording (reference numerals 5a to 5d are assigned to ink tanks for individual colors, that is, black, cyan, magenta, and yellow, see FIG. 1). Can be exchanged accordingly.

  In the recording mechanism unit 2, a carriage 9 is slidably mounted on a left and right rear guide shaft 6 and a front guide shaft 7 provided in parallel in the main body frame 1, and the recording head unit is mounted on the carriage 9. 3 is integrally attached.

  A carriage drive motor 10 disposed on the right rear side of the main body frame 1 and a timing belt 11 which is an endless belt are configured so that the carriage 9 can reciprocate in the left and right directions along the front and rear guide shafts 6 and 7. Yes. On the other hand, although not shown, the paper P is transported horizontally (in the direction of arrow Y in FIG. 1) in a direction perpendicular to the moving direction of the carriage 9 on the lower surface side of the recording head unit 3 by a known paper transport mechanism. .

  Outside the width of the sheet P to be conveyed, an ink receiving portion 12 is provided on one end side (the left end portion in FIG. 1 in the embodiment), and a maintenance unit 4 is disposed on the other end side. Yes. As a result, the recording head unit 3 periodically discharges ink to prevent nozzle clogging at the flushing position where the ink receiving portion 12 is provided, and receives ink at the ink receiving portion 12 during the recording operation. . At the head standby position on the other end side, the maintenance unit 4 is arranged to clean the nozzle surface, to perform recovery processing for selectively sucking ink for each color, and a damper device 13 (described later). A removal process for removing bubbles (air) in the ink flow path forming member is performed.

  As shown in FIG. 1, the ink tank 5 for each individual color can be inserted and mounted from the front at a position below the nozzle surface on the lower surface of the recording head unit 3. In FIG. 1, in order from the left, an ink tank 5a for black ink (BK), an ink tank 5b for cyan ink (C), an ink tank 5c for magenta ink (M), and an ink tank for yellow ink (Y). 5d is arranged horizontally and in parallel.

  On the rear side of each ink tank mounting portion, a hollow needle for ink supply (not shown) protrudes horizontally so as to face the insertion direction (rear side wall surface) of each color ink tank 5. The proximal end portion of the hollow needle corresponding to each color ink is connected to the recording head unit 3 via the corresponding flexible ink supply tubes 14a to 14d. In this case, the middle portions of the black and cyan ink supply tubes 14a and 14b and the middle portions of the magenta and yellow ink supply tubes 14c and 14d are stacked one above the other.

  Next, an embodiment of the recording head unit 3 mounted on the carriage 9 will be described with reference to FIGS. In this embodiment, for full color recording, the recording head unit 3 includes a head holder 20 formed in a box shape with a synthetic resin material and a lower surface side of a bottom plate 20a of the head holder 20 as shown in FIGS. An ink jet type front head unit 21 fixed to the bottom plate 20a, and a damper device 13 and an exhaust valve means 26 fixed to the upper side of the bottom plate 20a.

  On the lower surface of the front head unit 21, two rows of black ink (BK) nozzles 22 a and 22 a ′ from the left side in FIG. 2 (view of the front head unit 21 as viewed from the lower surface), and nozzles for cyan ink (C) The row of 22b, the row of nozzles 22c for yellow ink (Y), and the row of nozzles 22d for magenta ink (M) are formed long in the direction orthogonal to the moving direction (main scanning direction) of the carriage 9. ing. Each nozzle 22 is exposed downward so as to face the upper surface of the paper P.

  As shown in FIGS. 3 and 5, an ink supply port 81 of the cavity unit 80 is provided on one side of the front head unit 21 so as to open on the upper surface for each ink color (four colors in this embodiment). Ink is distributed through the ink supply channels extending from the ink supply ports 81 (indicated by reference numerals 81a to 81d individually), and the ink is ejected from the nozzles 22 by driving the piezoelectric actuator 23. Yes. A flexible flat cable 24 for applying a voltage to the piezoelectric actuator 23 is fixed on the upper surface of the piezoelectric actuator 23. Ink is supplied to each ink supply port 81 of the front head unit 21 from each ink tank 5 via the damper device 13. In the front head unit 21 of the embodiment, when the outer shape of the piezoelectric actuator 23 is made smaller than the outer shape of the cavity unit 80 and the piezoelectric actuator 23 is stacked on the back surface of the cavity unit 80, the ink supply port 81 is In addition, the back surface of the cavity unit 80 around the piezoelectric actuator is exposed to the back surface side of the front head unit 21.

  As shown in FIGS. 3 and 4, the front head unit 21 is fixed to the damper device 13 with a frame-shaped reinforcing frame 65 interposed on the back surface thereof. The size of the inner frame 65 a of the reinforcing frame 65 is slightly larger than the outer shape of the piezoelectric actuator 23 and smaller than the outer shape of the cavity unit 80. Therefore, the reinforcing frame 65 is laminated on the back surface of the cavity unit 80 by exposing the piezoelectric actuator 23 and the flexible flat cable 24 from the inside 65 a of the frame.

  The reinforcing frame 65 is made of metal (for example, SUS430), is thicker than the cavity unit 80, and has a large rigidity. The reinforcing frame 65 has an ink passage hole 66 that connects the ink outlet 41 of the damper device 13 and the ink supply port 81 of the front head unit 21 at a position corresponding to the ink supply port 81 of the cavity unit 80. ing. In this embodiment, four ink passage holes 66 are arranged in parallel so as to correspond to the four ink supply ports 81.

  An elastic seal member 67 is disposed between the damper device 13 and the reinforcing frame 65 so as to surround the periphery of the ink passage hole 66, and the elastic seal member 67 is fastened by fastening the damper device 13 and the reinforcing frame 65. In a compressed state, the connection between the ink passage hole 66 and the ink outlet 41 is sealed. In this embodiment, the screw 13b shown in FIG. 7 is screwed into the screw hole 65b of the reinforcing frame 65 via the mounting hole 13a of the damper device 13, so that the damper device 13 and the reinforcing frame 65 are fastened. Is done.

  The reinforcing frame 65 and the front head unit 21 are fixed by adhesion, but a sheet-like adhesive 68 is used as the adhesive. 2 and 8, the sheet-like adhesive 68 has a shape that continuously surrounds the piezoelectric actuator 23, and also has a shape that individually surrounds the four ink supply ports 81a to 81d. Yes.

  There are various types of the sheet-like adhesive 68, but in this embodiment, a thermoplastic type using a polyethylene resin as a base material and having excellent ink resistance is used. As its physical properties, Young's modulus is 1-1000 MPa, melting point is 80-180 ° C., the thickness after bonding the front head unit 21 and the reinforcing frame 65 is 5-100 μm, and the adhesive strength is 10 N or more (preferably 200 N or more). Are preferred.

  Next, the configuration of the front head unit 21 will be described. As shown in FIG. 6, the cavity unit 80 includes a nozzle plate 83, a first spacer plate 84, an auxiliary plate 85, two manifold plates 86a and 86b, a second spacer plate 87, a third spacer plate 88, and a base plate. A total of 89 thin plates are laminated and bonded with an adhesive.

  In the embodiment, except for the nozzle plate 83 made of synthetic resin, each of the plates 83 to 89 is made of 42% nickel alloy steel plate and has a thickness of about 50 to 150 μm. A large number of nozzles 22 having a minute diameter (in the embodiment, about 25 μm) are formed in the nozzle plate 83 at minute intervals. The nozzles 22 are arranged in five rows in a staggered manner along the first direction (long side direction, Y direction) of the nozzle plate 83.

  In the base plate 89, a plurality of pressure chambers 82 are arranged in five rows in a staggered manner along the long side (the Y direction) of the base plate 89. The front end portion of each pressure chamber 82 is similarly perforated in two staggered arrangements in the two spacer plates 87 and 88, the two manifold plates 86a and 86b, the auxiliary plate 85, and the first spacer plate 84. The nozzle plate 83 communicates with the nozzles 22 through minute through holes 90 serving as ink flow paths.

  The third spacer plate 88 adjacent to the lower surface of the base plate 89 is provided with a communication hole 91 as an ink flow path at a position corresponding to each other end portion in order to connect to the other end portion of each pressure chamber 82. Has been.

  The second spacer plate 87 adjacent to the lower surface of the third spacer plate 88 is provided with a connection channel 93 for supplying ink from the common ink chamber 92 to be described later to the pressure chambers 82.

  In the two manifold plates 86a and 86b, five common ink chambers 92 that are long along the long side direction (Y direction) are formed through the plate thickness so as to extend along each row of the nozzles 22. Has been. That is, by stacking two manifold plates 86a and 86b, and covering the upper surface with the second spacer plate 87 and covering the lower surface with the auxiliary plate 85, a total of five common ink chambers (manifold chambers) 92 are sealed. It is formed in a shape. Each common ink chamber 92 overlaps with a part of the pressure chamber 82 and extends long along the column direction of the pressure chambers 82 when viewed in plan from the stacking direction of the plates.

  On the lower surface side of the auxiliary plate 85 adjacent to the lower surface of the manifold plate 86a, an auxiliary chamber 94 isolated from the common ink chamber 92 is formed as a recess. The positions and shapes of the auxiliary chambers 94 are the same as those of the common ink chambers 92. Since the auxiliary plate 85 is a metal material that can be elastically deformed as appropriate, the thin plate-like bottom plate portion of the auxiliary chamber 94 can freely vibrate both on the common ink chamber 92 side and on the auxiliary chamber 94 side. . Even when the pressure fluctuation generated in the pressure chamber 82 propagates to the common ink chamber 92 during ink ejection, the bottom plate portion elastically deforms and vibrates, thereby having a damper effect of absorbing and attenuating the pressure fluctuation. This has the effect of preventing the crosstalk that the pressure fluctuation propagates to the other pressure chambers 82.

  Further, as shown in FIG. 6, four ink supply ports 81 are formed in one end portions of the base plate 89, the third spacer plate 88, and the second spacer plate 87 so as to correspond to the upper and lower positions. Yes. As described above, the ink outlet 41 of the damper device 13 is connected to these four ink supply ports (individually, 81a, 81b, 81c, 81d). The ink supplied from the ink tank 5 communicates with one end of the common ink chamber 92 through these ink supply ports 81.

  In the ink flow path from the ink supply port 81 to the nozzle 22, the ink is supplied from the ink supply port 81 to the common ink chamber 92 and then communicated between the connection flow path 93 of the second spacer plate 87 and the third spacer plate 88. Distribution is supplied to the other end of each pressure chamber 82 via the hole 91. As will be described later, by driving the piezoelectric actuator 23, the ink passes from the inside of each pressure chamber 82 through the through hole 90 to the nozzle 22 corresponding to the pressure chamber 82.

  In this embodiment, while four ink supply ports 81 are provided, as shown in FIG. 6, five common ink chambers 92 are provided, and the ink supply ports 81a are provided in FIG. Two common ink chambers 92, 92 arranged on the left side are connected. The ink supply port 81a is set so as to be supplied with black ink. This is because black ink is used more frequently than other color inks. The other ink supply ports 81b, 81c and 81d are supplied with cyan, yellow and magenta inks, respectively.

  The common ink chamber 92, the through hole 90, the communication hole 91, the connection channel 93, the auxiliary chamber 94, and the like in the metal plates 83 to 89 are formed by etching, electric discharge machining, or plasma machining. It is formed by laser processing or the like.

  On the other hand, the piezoelectric actuator 23 has a structure in which a plurality of piezoelectric sheets (not shown) and a top sheet are laminated, and the upper surface (wide width) of each piezoelectric sheet having a thickness of about 30 μm. On the surface), narrow individual electrodes are formed in a row along the long side direction (Y direction) at each location corresponding to each pressure chamber 82 in the cavity unit 80, and each individual electrode is formed in the long side direction. Extends to the vicinity of the edge of the long side of each piezoelectric sheet along the X direction orthogonal to the direction. A common electrode common to the plurality of pressure chambers 82 is formed on the upper surface (wide surface) of the even-numbered piezoelectric sheet from the bottom, and a surface electrode 95 is formed on the upper surface of the uppermost top sheet. A surface electrode electrically connected to each of the individual electrodes and a surface electrode electrically connected to the common electrode are provided.

  The piezoelectric actuator can also have a structure in which more piezoelectric sheets are laminated, similar to that disclosed in JP-A-4-341853.

  An adhesive sheet (not shown) made of an ink non-permeable synthetic resin material as an adhesive is formed on the entire lower surface (the wide surface facing the pressure chamber 82) of the plate-type piezoelectric actuator 23 having such a configuration. Next, the piezoelectric actuator 23 is bonded and fixed to the cavity unit 80 with the individual electrodes corresponding to the pressure chambers 82 in the cavity unit 80. Further, the flexible flat cable 24 is pressed against the upper surface of the piezoelectric actuator 23, so that various wiring patterns (not shown) in the flexible flat cable 24 are electrically connected to the surface electrodes 95. Are joined together.

  Next, the configuration of the damper device 13 as an ink flow path forming member will be described in detail with reference to FIGS. The damper device 13 includes a plurality of independent damper chambers 27 for each ink color, which are partitioned by sub-partition walls 35a and 30 that sandwich the main partition wall 35 and intersect the main partition wall. In the embodiment, a part of a black ink (BK) damper chamber 27a is disposed under the main partition wall 35, and a cyan ink (C) damper chamber 27b and a yellow ink (Y ) Damper chamber 27c and magenta ink (M) damper chamber 27d are partitioned and arranged by sub-partition walls 35a and 30, and are configured in two layers vertically.

  Specifically, the main body case 25 in the damper device 13 has a rectangular tubular side wall as an outer periphery, and is fixed so as to cover a box-shaped lower case 32 having an open top and bottom surface and an upper surface of the lower case 32. An upper case 31 is included. Both the upper case 31 and the lower case 32 are injection-molded with a synthetic resin material and are liquid-tightly coupled by ultrasonic welding or the like.

  The lower case 32 is provided with an opening on the lower surface thereof that opens most of the area of the lower surface, and a main partition wall 35 is formed at a position spaced in parallel from the opening and the upper opening surface. ing. The opening is sealed with a damper flexible film (synthetic resin film that is impermeable to air and liquid) 36. Specifically, the outer peripheral edge of the flexible film 36 is bonded to the lower end surface of the outer peripheral wall 37 that defines the outer periphery of the opening by bonding or ultrasonic welding. Between the flexible film 36 and the main partition wall 35, a first chamber 27a-1 of a damper chamber for black ink (BK) is formed. A gap for deformation of the flexible film 36 is secured between the flexible film 36 and the bottom plate 20 a of the head holder 20, and the damper device 13 is fixed to the head holder 20.

  On the upper surface of the main partition wall 35, a sub-partition wall 35a that rises integrally with the main partition wall 35 is formed, and a portion above the main partition wall 35 in the lower case 32 is described later. A plurality of damper chambers are formed in cooperation with the upper case 31. In the embodiment, two sub-partition walls 35a are spaced apart from each other, and together with the side wall of the lower case 32, 3 for cyan ink (C), yellow ink (Y), and magenta ink (M) are used. Individual damper chambers 27b to 27d (specifically, second chambers 39b to 39d of the damper chamber) are formed. Each sub partition wall 35a is formed to extend over the entire length of the lower case 32 as shown in FIG. 11, and is disposed at damper chambers 27b to 27d (specifically, the second chamber 39b to the second chamber 39) at positions away from the upper surface of the main partition wall 35. 39d) communicates with the ink outlets 41b to 41d for each ink color.

  Further, an additional sub partition wall 35 b is formed extending to a position off the upper surface of the main partition wall 35 in the vicinity of the ink outlets 41 b to 41 d, and between the sub partition wall 35 b and the side wall of the lower case 32, black A second chamber 39a of a damper chamber for ink (BK) is formed. The lower end of the second chamber 39a communicates with the ink outlet 41a (see FIGS. 4 and 11).

  The first chamber 27a-1 of the damper chamber for black ink (BK) passes through the passage 42 as a constricted portion penetrating the second chamber 39a in the vertical direction through the cylindrical portion formed along the sub partition wall 35b. It communicates (see FIG. 10, FIG. 11 and FIG. 13 (c)). The passage 42 is formed to have a cross-sectional area smaller than that of the first chamber 27a-1, and the flow path resistance is set to be larger than that in the first chamber 27a-1.

  The upper case 31 is formed in a flat shape having a plurality of recesses on the upper surface. The upper case 31 includes cyan ink (C) and yellow ink (which are partitioned by two sub-partition walls 30 at an upper position substantially corresponding to the first chamber 27a-1 of the damper chamber for black ink (BK). The first chambers 27b-1 to 27d-1 of the three damper chambers 27b to 27d for Y) and magenta ink (M) are formed to open upward (see FIG. 9). The sub partition wall 30 is located on the extended surface of the sub partition wall 35a of the lower case 32, and a plurality of passage holes 44 as throttle portions are formed in the bottom wall 29 of the first chambers 27b-1 to 27d-1. The first chambers 27 b-1 to 27 d-1 are formed so as to penetrate vertically, and the first chambers 27 b-1 to 27 d-1 individually communicate with the lower chamber (the chamber partitioned by the sub-partition wall 35 a in the lower case 32), that is, the second chambers 39 b-39 d. is doing.

  The passage hole 44 is formed to have a smaller cross-sectional area than each of the first chambers 27b-1 to 27d-1, and the flow path resistance is set larger than that of each of the first chambers 27b-1 to 27d-1.

  The upper open surfaces of the first chambers 27 b-1 to 27 d-1 are commonly sealed with a single flexible film 43 for damper (made of synthetic resin and impermeable to air and liquid). Specifically, the flexible film 43 is bonded to the outer peripheral wall defining the outer periphery of each first chamber and the upper end surface of the sub partition wall 30 by adhesion or ultrasonic welding.

  As shown in FIG. 10, the ink outlets 41 a to 41 d are arranged side by side on the lower surface of the lower case 32, and are opened downward at positions extending downward from the flexible film 36. On the other hand, the front head unit 21 includes a plurality of ink supply ports 81a to 81d communicating with the end portions of the ink supply channels (manifolds) for the respective ink colors on the upper surface at positions facing the respective ink outlets 41a to 41d. ing. Each of the ink outlets 41a to 41d passes through the opening 20b provided in the bottom plate 20a of the head holder 20 and communicates with each of the ink supply ports 81a to 81d of the front head unit 21 via the elastic seal member 67 as described above. is doing.

  As shown in FIGS. 4 and 9, an ink inlet 47 for each ink color (four in the embodiment) is provided in a portion 32a protruding in a flange shape from the side surface of the lower case 32 opposite to the ink outlets 41a to 41d. Ink inlets for black ink (BK), cyan ink (C), yellow ink (Y), and magenta ink (M) are indicated by 47a, 47b, 47c, and 47d, respectively, and are opened upward. ing.

  A joint member 45 having an ink flow path for each ink color is connected to these ink inflow ports 47 through seals 46 such as packing corresponding to the lower ends of the respective ink flow paths. The top ends of the ink supply tubes 14 a to 14 d for the respective ink colors are connected to the upper ends of the ink flow paths of the joint member 45.

  The ink inlet 47a for the black ink (BK) is connected to the first chamber of the corresponding damper chamber 27a via a concave passage 48 formed horizontally downward in the lower surface of the lower case 32. ing. The other ink inlets 47b to 47d are formed in the vertical direction (with respect to the surface formed by the main partition wall 35) along the concave passage 48 formed horizontally downward in the lower surface of the lower case 32 and one side wall of the lower case 32. It is connected to corresponding first chambers of damper chambers 27b to 27d via a communication passage 49 formed so as to extend in a substantially orthogonal direction and a communication passage 50 penetrating vertically through the upper case 31 (FIG. 9, FIG. 10, FIG. 12 (a), FIG. 12 (b) and FIG. 13 (b)). As the carriage 9 reciprocates in the main scanning direction (left-right direction) according to the recording operation, each ink supply tube 14 also moves in the left-right direction. When the carriage 9 moves in the left-right direction, the inertia force at the time of return causes the ink in each ink supply tube 14 to move. The pressure also varies greatly, and the pressure variation propagates to each damper chamber 27 via the ink inlet 47. In the present embodiment, since the opening surface of the communication path 50 is at a height position close to the lower surface of the flexible film 43, the ink that has flowed into the damper chambers 27 b to 27 d faces the opening surface of the communication path 50. Thus, it is possible to directly collide with the approaching flexible film 43, so that the dynamic pressure fluctuations of the ink in the ink supply tubes 14b to 14d can be efficiently absorbed (damped).

  The open lower surfaces of the ink inflow ports 47a to 47d and the concave passage 48 are sealed with portions where the flexible film 36 is extended.

  A U-shaped rib 35c in plan view with both ends connected to the side wall on the concave passage 48 side is flexible on the ceiling surface of the first chamber 27a-1 of the damper chamber for black ink (BK), that is, the lower surface of the main partition wall 35. The height of the conductive film 36 is not reached. For this reason, the space surrounded by the U-shaped rib 35c is provided with a space in which the ink does not enter, and the pressure variation of the ink described above is absorbed together with the air and the flexible film 36 therein. Yes.

  In addition, third chambers 55a to 55d of the damper chambers are formed in the upper surface of the upper case 31 so as to be independent of each other at positions corresponding to the second chambers 39a to 39d in the vicinity of the ink outlets 41a to 41d. Has been. Each of the third chambers 55a to 55d communicates with the corresponding second chamber 39a to 39d through an air hole 54 formed through the upper case 31. That is, the damper chambers 27a to 27d for each ink color are each composed of three chambers from the first chamber to the third chamber.

  Further, the upper case 31 is formed with an exhaust hole 53 communicating with the upper part of each of the second chambers 39a to 39d between the first chamber and the third chamber. The upper ends of the exhaust holes 53 are respectively connected to a plurality of exhaust passages 51 that are recessed in the upper surface of the upper case 31 independently of each other, and the exhaust passages extend in the longitudinal direction of the main body case (the ink inflow ports 47a to 47d). The other end extends in a direction orthogonal to the direction in which the ink outlets 41a to 41d are connected) and is connected to connection ports 52a, 52b, 52c, and 52d for the exhaust valve means 26 described later (see FIG. 9).

  Each exhaust hole 53 is formed in a cylindrical wall that hangs down from the upper case 31 into each of the second chambers 39a to 39d, and opens into each of the second chambers 39a to 39d at a predetermined distance from the upper case 31. ing. That is, as will be described later, even when the air bubbles in the second chambers 39a to 39d are discharged from the exhaust hole 53, an air layer corresponding to the hanging height of the cylindrical wall is secured above the second chambers 39a to 39d. ing. In addition, since an air layer is normally secured in the third chambers 55a to 55d, the air layer absorbs and relaxes the pressure fluctuations generated in the damper chambers 27a to 27d, so that the nozzles of the front head unit 21 are used. The pressure at 22 is kept uniform to improve the recording quality.

  The third chambers 55a to 55d and the exhaust passages 51 of the respective damper chambers are covered with open portions of the flexible film 43, and the respective chambers and passages are defined.

  The damper device 13 is fixed on the carriage 9 so that the main partition wall 35 and the flexible films 36 and 43 extend in parallel with the moving direction of the carriage 9, that is, the opening surface of the nozzle of the front head unit 21. Yes.

  Next, the exhaust valve means 26 will be described. The storage portion 34 integrally provided on one side of the lower case 32 (the right end in FIGS. 9 and 13A) is long in the vertical direction and has an opening in the vertical direction. The passage holes 56 are formed for each ink color (four). The side edge of the upper case 31 extends to a position covering the upper end of the storage portion 34, and the other end of each exhaust passage 51 is individually communicated with the upper end opening of each passage hole 56.

  Each of the passage holes 56 includes an upper half large-diameter portion 56a and a lower half small-diameter passage 56b. A small-diameter valve rod 58 is integrally formed at the lower end of the large-diameter valve body 57. A seal member 59 is disposed on the lower end surface side of the valve body 57 and is fitted on the valve rod 58. As the seal member 59, an elastic packing or the like is suitable. In this embodiment, an O-ring is applied to the seal member 59 and fitted to the valve rod 58. In addition, in addition to the seal member 59 and the valve body 57, the large diameter portion 56a has a spring means 60 (coil spring or the like) as an urging means for urging the valve body 57 in a direction to close the small diameter passage 56b. Has also been inserted. The valve rod 58 is inserted into the small diameter passage 56b, and the lower end of the valve rod 58 extends to the vicinity of the lower end opening of the small diameter passage 56b.

  The valve body 57 is always pressed downward by the spring means 60, and the state in which the seal member 59 is pressed and clamped between the valve body 57 and the bottom surface of the large-diameter portion 56a is the valve closed state (FIG. 13). (A)). On the other hand, a state in which the valve rod 58 is pushed upward by a projection 72a of a small cap member 72 described later is a valve open state.

  The maintenance unit 4 includes a cap member 71 that covers the opening surface of the nozzle 22 of the front head unit 21 so as to be openable and closable, and a plurality of small covers that individually open and close the lower end surface of the exhaust valve means 26, that is, the opening surfaces of the small-diameter passages 56b. And a cap member 72. Both cap members 71 and 72 are moved upward and downward of the nozzle 22 and the exhaust valve means 26 when the carriage 9 is moved to the standby position (right end position in FIG. 1) by a vertical movement mechanism 73 similar to a known maintenance unit. It rises so as to be in close contact with the lower end surface, and descends so as to be separated from those surfaces at other positions. Further, the cap member 71 is connected to the suction pump 74 in the same manner as a known maintenance unit, and the ink and foreign matters that are thickened from the nozzles 22 are removed by suction by driving the suction pump 74.

  Each small cap member 72 has a protrusion 72 a protruding from the cap member. When the small cap member 72 is in close contact with the lower end surface of the exhaust valve means 26, the protrusion 72 a causes the bubble rod 58 to bias the spring means 60. The seal member 59 is separated from the inner bottom portion of the large-diameter portion 56a to open the valve. Each small cap member 72 is connected to the suction pump 74 through a common flow path, and bubbles accumulated in the second chambers 39a to 39d of the respective damper chambers are collectively sucked and discharged by driving the suction pump 74. Is done. This is because the ink supplied from the ink tank 5 through the ink supply pipe 14 is temporarily stored in the second chambers 39a to 39d, so that bubbles are separated and floated from the ink and accumulated in the upper portions of the second chambers 39a to 39d. The air bubbles are discharged by the suction pump 74 as described above.

  The cap member 71 and the small cap member 72 are alternatively connected to the suction pump 74 by a switching valve 75. The cap member 71 and the small cap member 72 are simultaneously brought into close contact with the opening surface of the nozzle 22 and the lower end surface of the exhaust valve means 26 by the vertical movement mechanism 73. Preferably, the second chamber is firstly passed through the small cap member 72. The bubbles accumulated in the upper portions of 39a to 39d are discharged, and then the ink is discharged from the nozzle 22 through the cap member 71. If the cap member 71 alone is used to discharge the bubbles in the second chambers 39a to 39d, a large amount of ink must be discharged. However, by doing the above, the bubbles can be discharged and recorded with a small ink discharge amount. Head recovery processing can be performed.

  In addition, only ink suction from the nozzles 22 or only discharge of bubbles in the second chambers 39a to 39d can be performed independently.

  In place of the suction operation of the suction pump 74 as described above, a positive pressure is applied to the ink from the ink tank 5 side to suck and remove thickened ink and foreign matter from the nozzle 22, or the second chambers 39a to 39a. It is also possible to discharge 39d bubbles. Alternatively, the suction operation and the positive pressure application to the ink can be used in combination.

  According to the above-described configuration, when the front head unit 21 and the reinforcing frame 65 that are laminated are bonded to each other in the manufacturing process, the sheet-like adhesive 68 is first positioned and pressed and heated on the lower surface side of the reinforcing frame 65. Then, the sheet-like adhesive 68 is temporarily transferred to the reinforcing frame 65. Next, the ink supply port 81 of the cavity unit 80 and the ink passage hole 66 of the reinforcing frame 65 are aligned. The front head unit 21 is pressed and heated to the reinforcing frame 65 via the sheet-like adhesive 68, and the reinforcing frame 65 and the front head unit 21 are bonded and fixed. At this time, since the reinforcing frame 65 is bonded to the back surface of the cavity unit 80, the piezoelectric actuator 23 and the flexible flat cable 24 are exposed from the inside 65a of the reinforcing frame 65.

  By this process, the front head unit 21 and the reinforcing frame 65 are integrated as a subunit, and can be handled as a single component in the subsequent processes.

  Next, the subunitized front head unit 21 and the reinforcing frame 65 are bonded and fixed to the lower surface side of the bottom plate 20a of the head holder 20 (by UV adhesive or the like). At this time, the positioning is performed so that the ink passage hole 66 of the reinforcing frame 65 is exposed upward from the opening 20 b of the head holder 20.

  Then, an adhesive is injected from an opening 20c (FIG. 3) provided in the bottom plate 20a corresponding to the left and right side edges of the reinforcing frame 65, and the bottom plate 20a and the front head unit 21 are fixed. A gap between the outer periphery of the front head unit 21 and the side wall of the head holder 20 is also filled with an adhesive or a filler.

  Next, the damper device 13 is mounted inside the head holder 20, and the ink passage hole 66 of the reinforcing frame 65 and the ink outlet 41 of the damper device 13 are aligned with the elastic seal member 67 interposed therebetween. Then, as shown in FIG. 7, the screw 13 b is inserted into the mounting hole 13 a of the damper device 13 and screwed into the screw hole 65 b of the reinforcing frame 65. Thereby, the ink supply port 81 and the ink outlet 41 are connected via the elastic seal member 67 and the ink passage hole 66. Since the elastic seal member 67 is interposed in the compressed state due to the fastening, the ink supplied from the ink outlet 41 to the ink supply port 81 is sealed and does not leak outside. Further, the damper device 13 can be removed and replaced by removing the screw 13b as necessary.

  In the ink jet printer 100 including the front head unit 21 and the damper device 13 assembled in this way, since the reinforcing frame 65 is fixed to the front head unit 21, the damper device 13 is pressed so as to press the elastic seal member 67. Even if the reinforcing frame 65 is fastened, the reinforcing frame 65 supports the pressing force, so that the front head unit 21 is not deformed. And in patent document 2 of a prior art, although the sleeve for mounting | wearing the O-ring which is an elastic seal member, and the backup board for receiving the press of an O-ring were required, in this invention, these functions are provided. The reinforcing frame 65 is also used to reduce the number of parts.

Further, the reinforcing frame 65 is not attached only to the vicinity of the ink supply port 81 as in Patent Document 2, but is attached to the entire front head unit 21. Therefore, the front head unit 21 (sub unit) supported almost entirely by the rigid reinforcing frame 65 can be attached to and detached from other members, so that the front head unit 21 alone can be attached to and detached from other components. Also, there is an effect that the discharge characteristics are stabilized. In addition, as a subunit composed of the front head unit 21 and the reinforcing frame 65, handling in the process becomes easy.

  In addition, since the front head unit 21 and the reinforcing frame 65 are bonded with a sheet-like adhesive 68 instead of a liquid adhesive, it is possible to eliminate the protrusion of the adhesive. It is possible to avoid troubles caused by the adhesive. In addition, it is possible to eliminate application unevenness and variation of the adhesive, and it is possible to easily control the thickness.

  In particular, the sheet-like adhesive 68 has a Young's modulus of 1 to 1000 MPa, a melting point of 80 to 180 ° C., a thickness of 5 to 100 μm after the front head unit 21 and the reinforcing frame 65 are bonded, and an adhesive strength of 10 N or more ( By selecting the one preferably 200N or more, the sheet-like adhesive 68 also suppresses the vibration of the cavity unit 80 accompanying the vibration of the piezoelectric actuator 23, and also has an effect of preventing crosstalk between nozzles. That is, among the five nozzle rows, when discharging from nozzles in any row, discharging from any other row of nozzles had an adverse effect on discharge performance. According to the adhesive 68, vibration propagation for ejection can be absorbed and the above-mentioned adverse effects can be eliminated.

  Further, since the reinforcing frame 65 is made of metal, by using the sheet-like adhesive 68 having a linear expansion coefficient close to that of the front head unit 21 that is also made of metal and having a predetermined thickness secured at the interface thereof, It is highly resistant to environmental changes such as thermal shock and does not cause inconveniences such as peeling.

  Further, the sheet-like adhesive 68 is softened by press heating and its thickness is reduced, but at that time, waviness (distortion) or the like in the flatness of the reinforcing frame 65 can be absorbed and corrected.

  Further, as shown in FIGS. 2 and 8, the sheet-like adhesive 68 is adhered so as to continuously surround the periphery of the piezoelectric actuator 23 at the interface between the reinforcing frame 65 and the cavity unit 80. Therefore, when the surface of the nozzle 22 is wiped off with the wiper in the maintenance unit 4 described above, even if the ink wraps around the side surface or the back surface of the front head unit 21, the ink enters the piezoelectric actuator 23. Since it is blocked by the sheet-like adhesive 68, there is also an effect that it is possible to prevent problems such as electrical short-circuiting of the electrodes of the piezoelectric actuator 23 by ink.

  Further, since the sheet-like adhesive 68 has a shape that individually surrounds the ink supply port 81, the sheet-like adhesive 68 can prevent ink leakage from the ink supply port 81 at the interface between the reinforcing frame 65 and the cavity unit 80. Exhibits a sealing effect.

It is a top view of the recording mechanism part of an inkjet printer. It is a bottom view of a head holder. It is a disassembled perspective view of a front head unit, a reinforcement frame, a head holder, and a damper device. FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 2. It is a perspective view of a front head unit. It is a disassembled perspective view of a cavity unit. FIG. 7 is a sectional view taken along line VII-VII in FIG. 3. It is a partial cross-section schematic diagram which shows the position of a sheet-like adhesive agent. It is a top view of a damper device in the state where a flexible film 43 of the damper device was removed. It is a bottom view of a damper device in the state where flexible membrane 36 is removed. It is a top view of the lower case of a damper device. (A) is a top view of only the upper case of the damper device, (b) is a bottom view of only the upper case. (A) is a sectional view taken along line XIIIa-XIIIa in FIG. 9, (b) is a sectional view taken along line XIIIb-XIIIb in FIG. 9, and (c) is a sectional view taken along line XIIIc-XIIIc in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Inkjet printer 3 Recording head unit 4 Maintenance unit 5 (5a-5d) Ink tank 13 Damper device (ink flow path forming member) 13a Mounting hole 13b Screw 20 Head holder 20b Opening 21 Front head unit 22 Nozzle 23 Piezoelectric actuator 24 Flexible flat Cable 27 (27a to 27d) Damper chamber 41a to 41d Ink outlet 65 Reinforcement frame 65a In-frame 65b Screw hole 66 Ink passage hole 67 Elastic seal member 68 Sheet adhesive 80 Cavity unit 81 Ink supply port

Claims (6)

An ink jet comprising a front head unit having a plurality of nozzles arranged in a row on the front surface and an ink supply port on the back surface, and an ink flow path forming member for supplying ink to the ink supply port of the front head unit A printer head ,
The ink flow path forming member includes a damper chamber that is formed by a partition wall and a flexible film and stores ink, and an ink outlet that flows ink through the damper chamber,
The front head unit includes a cavity unit provided with the nozzle and a piezoelectric actuator laminated and adhered to the back surface of the cavity unit,
The front head unit is fixed to the ink flow path forming member with a frame-shaped reinforcing frame interposed on the back surface thereof,
The reinforcing frame is made of metal and is formed to have greater rigidity than the cavity unit,
Wherein the reinforcing frame, at a position corresponding to the ink supply port in said front head unit, the ink passage hole for connecting the ink outlet and the ink supply port in the ink flow path forming member is bored,
Wherein between the reinforcing frame and the ink flow path forming member is an ink jet printer head, wherein the resilient sealing member surrounds the periphery of the ink passage hole of the reinforcing frame is disposed in a compressed state.   2. The ink jet printer head according to claim 1, wherein the front head unit and the reinforcing frame are bonded with a sheet-like adhesive. The front head unit includes the cavity unit, the piezoelectric actuator, and a flexible flat cable that is laminated and bonded to the back surface of the piezoelectric actuator.
The reinforcing frame is bonded to the back surface of the cavity unit by exposing a piezoelectric actuator and a flexible flat cable from within the frame,
The inkjet printer head according to claim 1, wherein the sheet-like adhesive has a shape that continuously surrounds the periphery of the piezoelectric actuator.   The sheet-like adhesive has a Young's modulus of 1-1000 MPa, a melting point of 80-180 ° C., a thickness of 5-100 μm after the front head unit and the reinforcing frame are bonded, and an adhesive strength of 10 N or more. An ink jet printer head according to claim 2 or 3. The ink flow path forming member is made of resin, and the ink flow path forming member is screwed to the reinforcing frame,
5. The ink jet printer head according to claim 2, wherein the reinforcing frame and the front head unit are bonded with a sheet-like adhesive.   6. The ink jet printer head according to claim 5, wherein the ink flow path forming member is screwed to the reinforcing frame from the side.

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