JP2013126720A - Pressure buffering apparatus, liquid ejection head, liquid ejecting apparatus, and method of manufacturing pressure buffering apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve such a problem that a deposited surface flows, thinly extended molten burrs, projected at a chamber 15 side, is formed, and cracks are generated at the thinly extended molten burrs in a substrate 6 in a pressure buffering apparatus 1 with a flexible film 4 deposited on the substrate 6.SOLUTION: A pressure buffering apparatus includes: a substrate 6 having a recess 2 and an inflow communication port 3a communicated with an outer region on an inner surface of the recess 2; and a flexible film 4 bonded to an upper end surface TS of the recess 2, and closes an open end of the recess 2, and also includes a region R in which the thinly extended molten burrs, projected at the inner side rather than the inner surface SS of the recess 2 are not formed between the flexible film 4 and the upper end surface TS.

Description

  The present invention relates to a pressure buffering device that relieves pressure fluctuations of a liquid, a liquid jet head using the same, a liquid jetting device, and a method of manufacturing the pressure buffering device.

  In recent years, ink jet type liquid ejecting heads have been used in which ink droplets are ejected onto recording paper or the like to draw characters and figures, or liquid material is ejected onto the surface of an element substrate to form a functional thin film. In this method, ink or liquid material is supplied from a liquid tank to a liquid ejecting head via a supply pipe, and ink or liquid material filled in the channel is discharged from a nozzle communicating with the channel and recorded on a recording medium. When ejecting the liquid, the liquid ejecting head or the recording medium for recording the ejected liquid is moved to draw characters or graphics, or a functional thin film having a predetermined shape is formed.

  9 and 10 show a configuration diagram and a sectional view of a portion hh 'of the pressure buffer 100 connected to the ink jet head 120 which is this type of liquid ejecting head (FIGS. 4 and 5 of Patent Document 1). The pressure buffer 100 includes a recess 114 formed in the main body 112, an ink channel 107 constituted by a side wall 117, an ink outlet 108 communicating with the ink channel 107, and openings of the recess 114 and the ink channel 107. It is comprised from the flexible film 111 which plugs up. The side wall 117 and the chamber 115 are separated by a partition wall 110. The ink flowing from the ink inlet 102 is reduced in pressure fluctuation in the chamber 115 and is supplied from the ink outlet 108 to the inkjet head 120 via the opening 101 and the ink flow path 107.

  The inkjet head 120 and the pressure buffer 100 move while ejecting liquid. For this reason, pressure fluctuation due to inertia occurs in the ink filled in the pressure buffer 100 and the ink held in the tube connecting the liquid tank and the ink inlet 102. The flexible film 111 reduces the pressure fluctuation of the ink by the expansion and contraction of the film, and reduces the pressure fluctuation of the ink flowing out from the ink outflow path 108. As a result, the meniscus 104 formed on the nozzles of the inkjet head 120 can be kept in a constant shape, and a constant amount of ink droplets can be ejected from the nozzles at a constant speed.

JP 2008-110599 A

  The pressure buffer 100 is formed by molding a synthetic resin to form a recess 114 in the main body 112, and then bonding a flexible film 111 of the synthetic resin to the upper surface of the main body 112 by thermal welding. FIG. 11 is an enlarged view of a corner portion of the pressure shock absorber 100 in which the flexible film 111 is bonded to the main body 112 by heat welding. FIG. 11A is a partial plan view with the flexible film 111 removed, and FIG. 11B is a longitudinal sectional view of the part jj. When the flexible membrane 111 is heat-welded and bonded to the main body 112 while being pressed, the upper end of the right side of the concave portion 114 is transferred to the concave portion 114 side surface of the flexible membrane 111 and flows to the chamber 115 side as shown in the figure. A burr 118x extending thinly toward the inside of the recess 114 is formed. The upper end of the upper side of the recess 114 also flows toward the chamber 115 to form a burr 118y. A boundary surface 119 where the burr 118x and the burr 118y contact is formed at the upper corners of the upper side and the right side of the recess 114.

  In order to protect the flexible membrane 111, the pressure buffer 100 usually has a cover 121 provided with a gap above the flexible membrane 111. The cover 121 is fixed to the screw hole 122 of the main body 112 by screwing a screw 123. Therefore, stress is continuously applied to the burr 118x and the burr 118y, and the tip that is thinly extended breaks with time, and the main body 112 is cracked from the cracked portion. In particular, the boundary surface 119 between the burr 118x and the burr 118y is likely to crack, and a crack is generated in the main body 112, causing a problem that ink in the chamber 115 leaks to the outside.

  In addition to the case where the cover 121 is fixed with screws, cracks may occur in the main body 112 of the boundary surface 119 due to a local force applied from the flexible film 111 side. In particular, cracks may occur in the main body 112 at the corner boundary surface 119, and ink may leak out.

  In order to solve the above-mentioned problems, the present invention has been made with the object of providing a pressure buffer 100 with high reliability by suppressing the generation of burrs whose tip extends thinly toward the concave portion 114.

  The pressure buffering device of the present invention has a recess, a base having a communication port communicating with an external region on the inner surface of the recess, and a flexibility that joins the upper end surface of the recess and closes the opening end of the recess. And a region between the flexible membrane and the upper end surface, in which a thinly extending molten burr projecting inward from the inner side surface of the recess is not formed.

  Moreover, the said recessed part has a corner | angular part in the planar view seen from the normal line direction of the said upper end surface, and decided that the area | region where the said fusion | melting burr | flash is not formed is the said corner | angular part.

  Further, the region where the molten burr is not formed is the entire circumference of the opening end.

  Further, the base and the flexible film are made of synthetic resin.

  The flexible film is bonded to the upper end surface by heat welding.

  The base is made of polyethylene, and the flexible film is made of a multilayer film containing polyethylene.

  Further, a spring member is installed between the flexible film and the bottom surface of the recess.

  According to another aspect of the invention, there is provided a liquid ejecting head including the pressure buffer device according to any one of the above and a discharge unit that discharges the liquid supplied from the pressure buffer device.

  The liquid ejecting apparatus of the present invention includes the above-described liquid ejecting apparatus, a moving mechanism that reciprocates the liquid ejecting head, a liquid supply pipe that supplies liquid to the liquid ejecting head, and supplies the liquid to the liquid supply pipe. And a liquid tank.

  The manufacturing method of the pressure buffering device of the present invention includes a concave portion on one surface of a base, a concave portion forming step for forming a step portion between an upper end surface of the concave portion and an inner side surface of the concave portion, and a flexible film, And a welding step of joining to the upper end surface of the recess by thermal welding.

  Moreover, in the said recessed part formation process, the said recessed part had a corner | angular part by planar view seen from the normal line direction of the said upper end surface, and decided to form the said level | step-difference part in the said corner | angular part.

  Moreover, in the said recessed part formation process, it decided to form the said level | step-difference part over the perimeter of the opening end of the said recessed part.

  The step between the step bottom surface of the step portion and the upper end surface is 0.1 mm to 0.3 mm.

  In addition, the width of the step bottom surface of the step portion is not less than 0.4 mm.

  Further, the step side surface of the step portion has an inclined surface whose angle with the extended surface of the upper end surface does not exceed 90 °.

  The inclined surface has an arc shape that is recessed toward the base.

  The pressure buffer device of the present invention has a recess, a base body having a communication port communicating with an external region on the inner surface of the recess, a flexible film that is bonded to the upper end surface of the recess and closes the opening end of the recess, Between the flexible membrane and the upper end surface, there is a region in which a thinly extending molten burr projecting inward from the inner surface of the recess is not formed. Thereby, even if stress is applied to the upper end surface of the recess, it is possible to prevent the occurrence of a problem that the liquid is leaked due to a crack in the base due to the molten burr extending thinly toward the recess. .

It is explanatory drawing of the pressure buffer apparatus which concerns on 1st embodiment of this invention. It is a plane schematic diagram of the base | substrate of the pressure buffering apparatus which concerns on 2nd embodiment of this invention. It is explanatory drawing of the pressure buffer apparatus which concerns on 3rd embodiment of this invention. It is explanatory drawing of the manufacturing method of the pressure buffer apparatus which concerns on 4th embodiment of this invention. It is explanatory drawing of the manufacturing method of the pressure buffer apparatus which concerns on 4th embodiment of this invention. It is explanatory drawing of the manufacturing method of the pressure buffer apparatus which concerns on 4th embodiment of this invention. FIG. 10 is a configuration diagram of a liquid jet head according to a fifth embodiment of the present invention. FIG. 10 is a schematic perspective view of a liquid ejecting apparatus according to a sixth embodiment of the present invention. It is a schematic diagram of a conventionally known ink jet head and a pressure buffering device installed thereon. Sectional drawing of a conventionally well-known pressure buffer is represented. It is an enlarged view of the corner | angular part of a conventionally well-known pressure buffer.

(First embodiment)
FIG. 1 is an explanatory view of a pressure buffer device 1 according to a first embodiment of the present invention, and FIG. 1 (a) is a schematic plan view of a base 6 from which a flexible film 4 of the pressure buffer device 1 is removed. FIG. 1B is a schematic vertical sectional view of the portion AA. The pressure buffer 1 includes a base 6 having a recess 2 and a flexible film 4 that is bonded to the upper end surface TS of the recess 2 and closes the opening end of the recess 2. The recess 2 includes an inflow communication port 3a for allowing liquid to flow into the inner side surface SS from the outside, and an outflow communication port 3b for flowing the liquid to the outside. Further, in the region R over the entire circumference of the opening end KT of the recess 2, a thinly extending melt projecting inward from the inner surface SS of the recess 2 between the upper end surface TS of the recess 2 and the flexible film 4. It has the area | region R in which a burr | flash is not formed.

  As a result, no melt burr extending thinly inside the inner side surface SS of the recess 2 is formed in the entire region R of the opening end KT. Therefore, even if stress is applied to the upper end surface TS of the recess 2, Generation | occurrence | production of the malfunction that a crack enters and the liquid hold | maintained inside leaks can be prevented.

  Even when there is a molten burr protruding inside the recess 2, the tip does not extend thinly as shown in FIG. 11 (b) and has a curved shape, or the recess 2 of the flexible film 4. When the angle formed by the surface on the side and the surface of the molten burr is an obtuse angle, it does not correspond to the thinly extending molten burr and is included in the region R where the thinly extending molten burr is not formed. Further, even when there is a melt burr with a thin tip extending as shown in FIG. 11B, if the tip does not project inward from the inner surface SS of the recess 2, the melt extending thinly projecting inward. It is not included in the burr and is included in the region R where the thinly extending molten burr protruding inward is not formed.

  In the first embodiment, polyethylene is used as the substrate 6 and a multilayer film including a polyethylene layer is used as the flexible film 4. The flexible membrane 4 has a thickness of 40 μm to 70 μm. When it is thinner than 40 μm, the strength is lowered, and when it is thicker than 70 μm, the flexibility is lowered. In addition, although the recessed part 2 has a substantially square shape in planar view seen from the normal line direction of upper end surface TS, it cannot be overemphasized that it may be a polygon, a circle | round | yen, an ellipse etc. without being limited to this square. Further, the positions of the communication ports 3 a and 3 b may be installed on any side of the recess 2, or may be installed on the inner surface SS or the bottom surface BS of the recess 2.

  In the present embodiment, the vertical relationship is not particularly shown with respect to the direction of gravity. However, for example, the upper side of the pressure buffer 1 shown in FIG. The inflow communication port 3a can be located on the upper side, and the outflow communication port 3b can be located on the lower side in the gravity direction. On the contrary, although not shown, the inflow communication port 3a may be located on the lower side in the gravity direction, and the outflow communication port 3b may be located on the upper side in the gravity direction.

(Second embodiment)
FIG. 2 is a schematic plan view of the base 6 from which the flexible film 4 of the pressure buffer 1 according to the second embodiment of the present invention is removed. As shown in FIG. 2, the concave portion 2 is a quadrangle in a plan view seen from the normal direction of the upper end surface TS, and each of the corner portions has a thinly extending molten burr that protrudes inward from the inner side surface SS of the concave portion 2. The region R is not formed. Other recesses 2 and communication ports 3a and 3b are the same as those in the first embodiment, and a description thereof will be omitted.

  In particular, at the corner portion of the upper end surface TS, the molten material moves from both sides to form a boundary surface 119 (see FIG. 11), and the base body 6 is likely to crack at the boundary surface 119. Therefore, a region R is formed between the flexible film 4 at each corner and the upper end surface TS where no thinly extending molten burrs projecting inward from the inner side surface SS are formed, and stress is applied to the upper end surface TS of the recess 2. Even if it is applied, the base 6 is not cracked, and it is possible to prevent a problem that the liquid held inside leaks. In the second embodiment, all the corners are the regions R in which the thinly extending molten burrs that protrude inward from the inner surface SS are not formed, but instead, the corners where cracks are most likely to occur. Only a region R in which a thinly extending molten burr projecting inward from the inner side surface SS is not formed may be used.

(Third embodiment)
FIG. 3 is an explanatory view of the pressure buffering device 1 according to the third embodiment of the present invention, and FIG. 3A is a schematic plan view of the base 6 from which the flexible film 4 of the pressure buffering device 1 is removed. FIG. 3B is a schematic cross-sectional view of a portion BB of the pressure buffer device 1.

  The pressure buffer device 1 includes a base 6 having a recess 2, a flexible film 4 that is bonded to the upper end surface TS of the recess 2 and closes the opening end of the recess 2, a flexible film 4, and a bottom surface BS of the recess 2. And a spring member 9 installed between the two. The base body 6 includes an inflow connection portion 7a through which liquid flows into the outer surface GS from the outside and an outflow connection portion 7b through which liquid flows out. The inflow connection portion 7 a communicates with an inflow communication port 3 a formed in the bottom surface BS of the recess 2. The outflow connection portion 7b communicates with the outflow communication port 3b through the flow path 11 formed of the recess portion 2 adjacent to the outflow port 17 formed in the bottom surface BS of the recess portion 2 and the chamber 15. Then, a region R is formed between the upper end surface TS of the concave portion 2 of the chamber 15 and the flow path 11 and the flexible film 4 in which a thinly extending molten burr projecting inward from the inner side surface SS of the concave portion 2 is not formed. .

  The liquid flows into the chamber 15 from the inflow connection portion 7a through the inflow communication port 3a, and flows out from the outflow connection portion 7b through the outflow communication port 3b and the flow path 11. A plate spring is used as the spring member 9. The hole provided at the end of the leaf spring is fitted into the protrusion 16 provided on the bottom surface BS of the recess 2, and the spring member 9 is engaged with the base 6. The upper end surface of the leaf spring is in contact with the flexible membrane 4, and even when the chamber 15 has a large negative pressure, the flexible membrane 4 is attracted to the bottom surface BS and the inflow communication port 3a and the outflow communication port 3b are blocked. Is prevented. When pressure fluctuation occurs in the liquid filled in the chamber 15, the flexible film 4 expands and contracts and is displaced in the y direction, thereby relaxing the pressure fluctuation of the liquid.

  Further, in FIG. 3A, the pressure buffer 1 is erected with the upper side of the base 6 facing upward (+ z direction) with respect to the gravity g and the lower side facing downward with respect to the gravity g (−z direction). For example, bubbles mixed in the liquid gather above the chamber 15. Therefore, the bubbles mixed in the liquid can be easily discharged from the flow path 11, and liquid replacement and cleaning are facilitated.

  In the third embodiment, the entire periphery of the corners of the inner surface SS and the upper end surface TS of the recess 2 is defined as a region R in which a thinly extending molten burr that protrudes inward from the inner surface SS is not formed. Even if the region R is configured only in the region that becomes the corner portion of the chamber 15 or the flow path 11 in plan view as in the second embodiment, the operational effects of the present invention can be achieved. Moreover, you may comprise the area | region R only in a specific corner | angular part, for example, the corner | angular part which becomes the acute angle in planar view.

(Fourth embodiment)
4-6 is a figure for demonstrating the manufacturing method of the pressure buffer 1 which concerns on 4th embodiment of this invention. The same portions or portions having the same function are denoted by the same reference numerals.

  FIG. 4A is a schematic cross-sectional view of the substrate 6 formed by the recess forming step, and FIGS. 4B and 4C are enlarged views of the stepped portion 5. FIG. 4B shows a case where the angle θ between the step side surface DS and the extended surface of the upper end surface TS is 90 °, and FIG. 4C shows an inclined surface where the angle θ does not exceed 90 ° (solid line). The broken line is the case where the inclined surface has an arc shape recessed toward the base 6 side.

  When the concave portion 2 has a corner portion in a plan view seen from the normal direction of the upper end surface TS, the step portion 5 has a step portion 5 at the opening end (intersection of the inner side surface SS and the upper end surface TS) of the corner portion. Can be formed. In particular, the corner portion of the upper end surface TS moves from both sides to form a boundary surface 119 (see FIG. 11), and a crack is likely to occur in the base body 6 at the boundary surface 119. Further, the step portion 5 may be formed over the entire circumference of the opening end of the recess 2. If it is formed on the entire circumference, cracks can be prevented from occurring even when a local stress is applied over the entire open end of the recess 2.

  The base 6 was made of polyethylene, and the recess 2 and the step 5 were formed by molding. A step portion 5 is formed on one surface of the base 6 between the recess 2 and the upper end surface TS of the recess 2 and the inner surface SS of the recess 2. The height h of the step side surface DS of the step portion 5 is 0.1 mm to 0.3 mm, preferably 0.2 mm. When the height h is lower than 0.1 mm, the synthetic resin on the upper end surface TS flows to the concave portion 2 side and protrudes from the inner side surface SS to the concave portion 2 side when the flexible film 4 and the substrate 6 are thermally welded. When the height h is higher than 0.3 mm, a molten burr is likely to occur at the upper part of the step side surface DS, and a crack is likely to occur in the substrate 6.

  Further, the width d of the step bottom DB (the distance from the corner between the inner side surface SS and the step bottom DB to the corner of the step bottom DB and the step side DS) should not be less than 0.4 mm. When the width d is less than 0.4 mm, the synthetic resin on the upper end surface TS flows to the concave portion 2 side during the thermal welding of the flexible film 4 and the base 6 and melts to protrude to the concave portion 2 side from the inner side surface SS. Burr is likely to occur.

  FIG. 5 is an explanatory view of the welding process, and FIG. 6 is an enlarged view of the step portion 5 after the flexible film 4 is thermally welded. The base 6 is placed on the surface plate 19, and the heating surface plate 18 is pressed against the flexible film 4 to thermally weld the flexible film 4 and the base 6. The flexible film 4 is a two-layer film of polyethylene and nylon and has a thickness of 40 μm to 70 μm. The polyethylene side of the flexible membrane 4 is placed on the base 6 side. The heating temperature is set to about 150 ° C., a pressure of about 0.3 MPa is applied, and welding is performed in a short time of several seconds to 10 seconds. The upper end portion of the base 6 (the material near the upper end surface TS) flows toward the concave portion 2 so as to fill the step portion 5 as indicated by the arrow, and the width d of the step bottom surface DB becomes narrower than that before heat welding or the step. Fill in part 5. However, there is no melting burr in which the fluid portion protrudes toward the concave portion 2 from the inner surface SS.

  In the above welding conditions, as shown in FIG. 4B, the angle θ between the step side surface DS and the extended surface of the upper end surface TS is set to 90 °, and it extends thinly so as to protrude inward from the inner surface SS of the recess 2. Molten burrs are not formed. As shown in FIG. 4C, if the step side surface DS is an inclined surface whose angle θ does not exceed 90 °, even if the material of the upper end surface TS flows to the concave portion 2 side during thermal welding, the flexible film Only the gap between 4 and the step side surface DS or the step bottom surface DB is filled. For this reason, no molten burrs or wrinkles projecting toward the concave portion 2 are formed. Also in this case, the width d of the step bottom surface DB is not less than 0.4 mm, and the height h of the step side surface DS is 0.1 mm to 0.3 mm, preferably 0.2 mm.

  In addition, as shown with the broken line of FIG.4 (c), it is good also as a circular arc shape in which an inclined surface dents to the base | substrate 6 side, and it is good also as the convex shape which swells to the flexible membrane 4 side. Even when the upper end portion flows toward the concave portion 2 at the time of heat welding, it flows so as to fill the gap between the flexible film 4 and the step side surface DS or the step bottom surface DB. Protruding thin and extended melt burrs are not formed. As a result, even if the flexible film 4 is pressed from the outside or a local stress is applied to the upper end surface TS of the recess 2, the base 6 is cracked and the liquid inside leaks. Can be prevented.

(Fifth embodiment)
FIG. 7 is a configuration diagram of the liquid jet head 10 according to the fifth embodiment of the present invention. The same reference numerals are assigned to the same parts or parts having the same function.

  As shown in FIG. 7, the liquid jet head 10 includes a pressure buffer 1, a head chip 20, and a fixing member 21 for fixing the head chip 20. The liquid jet head 10 is erected with the pressure buffer 1 upward and the head chip 20 downward with respect to the direction of gravity g. In the pressure buffer 1, the liquid flows in from the inflow connection 7 a fixed above the base 6, and the liquid whose pressure fluctuation is relaxed flows out of the outflow connection 7 b and is supplied to the head chip 20. The head chip 20 discharges droplets downward from a number of nozzles (not shown) and records on a recording medium (not shown). Here, the pressure buffer 1 described in the first to fourth embodiments is used.

(Sixth embodiment)
FIG. 8 is a schematic perspective view of a liquid ejecting apparatus 30 according to the sixth embodiment of the present invention. The liquid ejecting apparatus 30 includes a moving mechanism 40 that reciprocates the liquid ejecting heads 10 and 10 ′, flow path portions 35 and 35 ′ that supply liquid to the liquid ejecting heads 10 and 10 ′, and flow path portions 35 and 35 ′. Liquid pumps 33 and 33 'for supplying liquid to the liquid tanks and liquid tanks 34 and 34'. Each liquid ejecting head 10, 10 ′ includes a plurality of ejection grooves, and ejects liquid droplets from nozzles communicating with the ejection grooves. The liquid ejecting heads 10 and 10 'are the same as those described in the fifth embodiment.

  The liquid ejecting apparatus 30 includes a pair of conveying units 41 and 42 that convey a recording medium 44 such as paper in the main scanning direction, liquid ejecting heads 10 and 10 ′ that eject liquid onto the recording medium 44, and a liquid ejecting head. 10 and 10 ′, liquid pumps 33 and 33 ′ for supplying the liquid stored in the liquid tanks 34 and 34 ′ to the flow path sections 35 and 35 ′, and the liquid jet heads 10 and 10 ′. A moving mechanism 40 that scans 10 ′ in the sub-scanning direction orthogonal to the main scanning direction is provided. A control unit (not shown) controls and drives the liquid ejecting heads 10 and 10 ′, the moving mechanism 40, and the transporting units 41 and 42.

  The pair of conveying means 41 and 42 includes a grid roller and a pinch roller that extend in the sub-scanning direction and rotate while contacting the roller surface. A grid roller and a pinch roller are moved around the axis by a motor (not shown), and the recording medium 44 sandwiched between the rollers is conveyed in the main scanning direction. The moving mechanism 40 couples a pair of guide rails 36 and 37 extending in the sub-scanning direction, a carriage unit 43 slidable along the pair of guide rails 36 and 37, and the carriage unit 43 to move in the sub-scanning direction. An endless belt 38 is provided, and a motor 39 that rotates the endless belt 38 via a pulley (not shown) is provided.

  The carriage unit 43 mounts a plurality of liquid jet heads 10 and 10 ′, and discharges four types of liquid droplets, for example, yellow, magenta, cyan, and black. The liquid tanks 34 and 34 'store liquids of corresponding colors and supply them to the liquid jet heads 10 and 10' via the liquid pumps 33 and 33 'and the flow path portions 35 and 35'. Each liquid ejecting head 10, 10 ′ ejects droplets of each color according to the drive signal. An arbitrary pattern is recorded on the recording medium 44 by controlling the timing of ejecting the liquid from the liquid ejecting heads 10, 10 ′, the rotation of the motor 39 that drives the carriage unit 43, and the conveyance speed of the recording medium 44. I can.

  As in the fifth and sixth embodiments, even if stress is applied to the upper end surface TS of the recess 2 of the pressure buffering device 1, the base 6 will not crack and the liquid inside will not leak, so the pressure buffering The assembly process of the apparatus 1 is facilitated, and the reliability of the liquid ejecting head 10 and the liquid ejecting apparatus 30 is improved.

DESCRIPTION OF SYMBOLS 1 Pressure buffer 2 Recess 3a Inflow communication port, 3b Outflow communication port 4 Flexible film 5 Step part 6 Base | substrate 7a Inflow connection part, 7b Outflow connection part 9 Spring member 10 Liquid ejecting head 20 Head chip 30 Liquid ejecting apparatus

Claims (16)

A base body having a recess and a communication port communicating with an external region on the inner surface of the recess;
A flexible membrane bonded to the upper end surface of the recess and closing the opening end of the recess,
The pressure buffering apparatus which has the area | region where the thinly extended fusion | melting burr | flash which protrudes inside from the inner surface of the said recessed part is not formed between the said flexible film | membrane and the said upper end surface. The concave portion has a corner portion in a plan view seen from the normal direction of the upper end surface,
The pressure buffering device according to claim 1, wherein the region where the molten burr is not formed is the corner portion.   The pressure buffering device according to claim 1 or 2, wherein the region where the molten burr is not formed is the entire circumference of the opening end.   The pressure buffering device according to any one of claims 1 to 3, wherein the base body and the flexible film are made of a synthetic resin.   The pressure buffer according to any one of claims 1 to 4, wherein the flexible film is joined to the upper end surface by heat welding.   The pressure buffering device according to any one of claims 1 to 5, wherein the base is made of polyethylene, and the flexible membrane is a multilayer film containing polyethylene.   The pressure buffer device according to any one of claims 1 to 6, wherein a spring member is installed between the flexible membrane and the bottom surface of the recess. A pressure damper according to claim 1;
A liquid ejecting head comprising: a discharge unit that discharges the liquid supplied from the pressure buffering device. A liquid ejecting head according to claim 8;
A moving mechanism for reciprocating the liquid jet head;
A liquid supply pipe for supplying a liquid to the liquid ejecting head;
And a liquid tank that supplies the liquid to the liquid supply pipe. A recess formed on one surface of the base, and a step forming a step between the upper end surface of the recess and the inner surface of the recess; and
And a welding step of joining the flexible film to the upper end surface of the recess by thermal welding.   The method for manufacturing a pressure buffering device according to claim 10, wherein, in the concave portion forming step, the concave portion has a corner portion in a plan view seen from a normal direction of the upper end surface, and the step portion is formed in the corner portion.   The manufacturing method of the pressure buffering device according to claim 10, wherein, in the recess forming step, the stepped portion is formed over the entire circumference of the opening end of the recess.   The manufacturing method of the pressure buffering device according to any one of claims 10 to 12, wherein a step between the step bottom surface of the step portion and the upper end surface is 0.1 mm to 0.3 mm.   The manufacturing method of the pressure buffering apparatus as described in any one of Claims 10-13 in which the width | variety of the level | step difference bottom face of the said level | step-difference part is not less than 0.4 mm.   The method of manufacturing a pressure buffer device according to any one of claims 10 to 14, wherein the step side surface of the step portion forms an inclined surface whose angle with the extended surface of the upper end surface does not exceed 90 °.   The method of manufacturing a pressure buffering device according to claim 15, wherein the inclined surface has an arc shape that is recessed toward the base.

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