JP2012011629A - Liquid droplet ejection head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid droplet ejection head in which back flow of liquid is prevented in normal circulation, and reverse flow of the liquid is generated in maintenance or the like.SOLUTION: In the liquid droplet ejection head 10 in which liquid is supplied to a pressure chamber 14 by circulation, the cross-sectional area of an individual supply flow passage 26 communicating the pressure chamber 14 with a supply flow passage branch 24 is formed so as to gradually decrease toward the pressure chamber 14 from the supply flow passage branch 24, and the cross-sectional area of an individual recovery flow passage 36 communicating the pressure chamber 14 with a recovery flow passage branch 34 is formed so as to gradually decrease toward the recovery flow passage branch 34 from the pressure chamber 14. Thus, back flow of liquid is prevented in normal circulation, and reverse flow of the liquid is generated in maintenance or the like.

Description

  The present invention relates to a droplet discharge head, and more particularly to a droplet discharge head that circulates liquid and supplies the pressure chamber to a pressure chamber.

  A droplet discharge head used in an ink jet recording apparatus has a lot of ink in which the solvent in the ink tends to volatilize (for example, ink using water as a solvent), insoluble components and polymer compounds dispersed in the ink. When the ink contained (for example, ink using a pigment or resin fine particle dispersion) is used, the solvent in the ink volatilizes from the nozzle not only during printing standby but also during printing, and the ink viscosity near the nozzle increases. A phenomenon occurs. When the ink viscosity in the vicinity of the nozzle is increased, the fluid resistance inside the nozzle is increased, resulting in ejection failure such as variation in the flying volume and ejection direction of the ejected ink droplet, or non-ejection. As a result, the positional deviation and size error of the dots that are ejected onto the print medium, and the missing dots are caused.

  To solve such a problem, a technique has been proposed in which the ink viscosity in the vicinity of the nozzles is prevented from increasing by constantly circulating the ink even during printing (for example, Patent Document 1). In this technology, in addition to a common supply channel (common supply channel) for supplying ink to each pressure chamber, a common recovery channel (common recovery channel) for recovering ink from each pressure chamber is provided. An ink flow from the flow path toward the common recovery flow path is formed, and the ink is circulated and supplied.

  By the way, in such a circulation type liquid droplet ejection head, each pressure chamber communicates with a common supply channel via an individual supply channel (individual supply channel), and an individual recovery channel (individual recovery channel). ) To the common recovery flow path. The individual supply flow path and the individual recovery flow path are designed so as to increase the inertance so that ink does not flow into the common supply flow path and the common recovery flow path during ejection.

  However, in such a circulation type droplet discharge head, since the flow paths are arranged in parallel, the ink flow may occur in a direction opposite to the direction intended during discharge or maintenance. If the ink flow in the reverse direction occurs, not only refreshing of the ink is performed, but also the flow of discharging the air bubble when the air bubbles are mixed in. There is a problem of end. In addition, the occurrence of an asymmetric flow has a problem in that it affects the peripherally normally circulated nozzles.

  In view of this, a technique has been proposed in which a check valve is provided in the flow path in order to prevent such backflow in the circulation type droplet discharge head (for example, Patent Document 2).

JP 2009-241316 A JP 2009-248212 A

  However, since the check valve has a movable structure, there is a drawback that the durability of the head is lowered. In addition, there is a disadvantage that the circulation operation cannot be performed in the reverse direction during maintenance. In addition, in a head in which nozzles are arranged at a high density, the flow path structure is highly precise, so there is a drawback that it is technically difficult to employ a check valve.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a droplet discharge head capable of generating a flow in the reverse direction during maintenance while preventing a reverse flow in normal circulation. And

  In order to achieve the above object, the invention according to claim 1 provides a plurality of pressure chambers arranged in parallel, a common supply channel arranged along the arrangement of the pressure chambers, and an arrangement of the pressure chambers. A common recovery flow path arranged along the plurality of pressure supply chambers, a plurality of individual supply flow paths individually communicating with the common supply flow path, and a pressure recovery chamber individually communicating with the common recovery flow path. A plurality of individual recovery flow paths, and a liquid droplet ejection head that generates a flow from the common supply flow path toward the common recovery flow path through the pressure chamber and supplies the liquid to the pressure chamber. Each individual supply channel is formed such that a cross-sectional area gradually decreases from the common supply channel toward the pressure chamber, and each individual recovery channel is directed from the pressure chamber toward the common recovery channel. A liquid characterized by being formed so that its cross-sectional area gradually decreases To provide a discharge head.

  According to the present invention, the channel resistance of each individual supply channel that communicates each pressure chamber and the common supply channel is formed so as to increase from the common supply channel toward the pressure chamber. Further, the channel resistance of each individual recovery channel that communicates each pressure chamber and the common recovery channel is formed so as to increase from the pressure chamber toward the common recovery channel. Thereby, it is possible to generate a flow in the reverse direction at the time of maintenance or the like while preventing a reverse flow in normal circulation. In addition, the aspect which changes a cross-sectional area is not specifically limited, For example, it can change continuously and in steps.

  According to a second aspect of the present invention, in order to achieve the above object, each of the individual supply flow paths is formed by inclining at least one surface of the flow path wall so that the cross-sectional area is different from the common supply flow path. Each of the individual recovery channels is formed so as to be inclined toward the pressure chamber, and at least one surface of the channel wall is inclined, so that a cross-sectional area is increased from the pressure chamber to the common recovery channel. The droplet discharge head according to claim 1, wherein the droplet discharge head is formed so as to gradually decrease toward the path.

  According to the present invention, each individual supply channel is formed such that at least one surface of the channel wall is inclined so that the cross-sectional area gradually decreases from the common supply channel toward the pressure chamber. The Each individual recovery channel is formed such that at least one surface of the channel wall is inclined, so that the cross-sectional area gradually decreases from the pressure chamber toward the common recovery channel. Thereby, each individual supply channel and each individual recovery channel having a desired channel resistance can be formed with a simple channel structure.

  According to a third aspect of the present invention, in order to achieve the above object, each individual supply channel includes a cross-sectional area of a communication port that communicates with the common supply channel, and a cross-sectional area of a communication port that communicates with the pressure chamber. The individual recovery flow path has a cross-sectional area of a communication port communicating with the pressure chamber and a cross-sectional area of a communication port communicating with the common recovery flow path. 3. The droplet discharge head according to claim 1, wherein the droplet discharge head is formed to have a ratio of 110% or more.

  According to the present invention, each individual supply channel has a ratio of the cross-sectional area of the communication port (inlet) communicating with the common supply channel and the cross-sectional area of the communication port (outlet) communicating with the pressure chamber of 110% or more. It is formed to become. Similarly, the ratio of the cross-sectional area of the communication port (inlet) communicating with the pressure chamber to the cross-sectional area of the communication port (outlet) communicating with the common recovery channel is 110% or more in each individual recovery channel. Formed. That is, for each individual supply channel and each individual recovery channel, the ratio of the cross-sectional area of the inlet to the outlet (inlet / outlet) is formed to be 110% or more. As a result, it is possible to provide a flow path structure sufficient to generate a flow in the reverse direction during maintenance and the like while preventing a reverse flow during normal circulation.

  In the invention according to claim 4, in order to achieve the object, each of the individual supply channels has a chamfered edge portion of a communication port that communicates with the common supply channel, 4. The droplet discharge head according to claim 1, wherein an edge of a communication port communicating with the common recovery channel is formed to protrude into the common recovery channel. .

  According to the present invention, the edge of the communication port communicating with the common supply channel of each individual supply channel is chamfered. Moreover, the edge part of the communicating port connected to the common recovery flow path of each individual recovery flow path is formed to protrude into the common recovery flow path. As a result, the liquid can easily flow from the common supply channel to the individual supply channel, and the liquid can easily flow from the individual recovery channel to the common recovery channel. Accordingly, it is possible to generate a flow in the reverse direction during maintenance or the like while preventing the reverse flow in the normal circulation more effectively.

  In order to achieve the above object, the invention according to claim 5 includes a plurality of pressure chambers arranged in parallel, a common supply channel arranged along the arrangement of the pressure chambers, and the arrangement of the pressure chambers. A common recovery flow path arranged along the plurality of pressure supply chambers, a plurality of individual supply flow paths individually communicating with the common supply flow path, and a pressure recovery chamber individually communicating with the common recovery flow path. A plurality of individual recovery flow paths, and a liquid droplet ejection head that generates a flow from the common supply flow path toward the common recovery flow path through the pressure chamber and supplies the liquid to the pressure chamber. Each individual supply channel is chamfered at the edge of the communication port communicating with the common supply channel, and each individual recovery channel is formed at the edge of the communication port communicating with the common recovery channel. Provided is a droplet discharge head characterized by being formed to protrude into a path

  According to the present invention, the edge of the communication port communicating with the common supply channel of each individual supply channel is chamfered. Moreover, the edge part of the communicating port connected to the common recovery flow path of each individual recovery flow path is formed to protrude into the common recovery flow path. As a result, the liquid can easily flow from the common supply channel to the individual supply channel, and the liquid can easily flow from the individual recovery channel to the common recovery channel. Thereby, it is possible to generate a flow in the reverse direction at the time of maintenance or the like while preventing a reverse flow in normal circulation.

  According to a sixth aspect of the present invention, in order to achieve the above object, each individual supply channel has an edge of a side located on the upstream side with respect to the liquid flow direction of the liquid flowing through the common supply channel. 6. The droplet discharge head according to claim 4, wherein the droplet discharge head is chamfered.

  According to the present invention, each individual supply channel is chamfered at the edge located on the upstream side with respect to the liquid flow direction of the liquid flowing through the common supply channel. Accordingly, it is possible to generate a flow in the reverse direction during maintenance or the like while preventing the reverse flow in the normal circulation more effectively.

  In the invention according to claim 7, in order to achieve the above object, each of the individual recovery channels has an edge of a side located on the upstream side with respect to the liquid flow direction of the liquid flowing through the common recovery channel. The droplet discharge head according to claim 4, wherein the droplet discharge head is formed so as to protrude into the common recovery channel.

  According to the present invention, each individual recovery channel is formed such that the edge of the side located upstream from the liquid flow direction of the liquid flowing through the common recovery channel projects into the common recovery channel. Accordingly, it is possible to generate a flow in the reverse direction during maintenance or the like while preventing the reverse flow in the normal circulation more effectively.

  In the invention according to claim 8, in order to achieve the above object, each of the individual recovery channels is formed with an inclined outer periphery of an edge formed so as to protrude into the common recovery channel. A droplet discharge head according to any one of claims 4 to 7 is provided.

  According to the present invention, each individual recovery channel is formed such that the outer periphery of the edge formed protruding into the common recovery channel is inclined. Thereby, it can prevent that foreign materials, such as a bubble, remain in a protrusion part.

  According to a ninth aspect of the present invention, in order to achieve the object, each of the individual supply channels has a chamfer formed at an edge of a communication port communicating with the common supply channel. The droplet discharge according to any one of claims 4 to 8, wherein the droplet discharge is formed with a chamfering length of 5% or more with respect to the width and a chamfering angle of 20 ° to 70 °. Provide the head.

  According to the present invention, each individual supply channel is chamfered with a chamfering length of 5% or more and a chamfering angle of 20 ° to 70 ° with respect to the width of the common supply channel. As a result, it is possible to provide a flow path structure sufficient to generate a flow in the reverse direction during maintenance and the like while preventing a reverse flow during normal circulation.

  According to a tenth aspect of the present invention, in order to achieve the object, each of the individual recovery channels has an edge of a communication port that communicates with the common recovery channel with respect to the width of the common recovery channel. 10. The droplet discharge head according to claim 4, wherein the droplet discharge head is formed to protrude into the common recovery flow path with a protrusion amount of% or more.

  According to the present invention, each of the individual recovery channels has an edge of the communication port communicating with the common recovery channel in the common recovery channel with a protruding amount of 5% or more with respect to the width of each individual supply channel. Protrusively formed. As a result, it is possible to provide a flow path structure sufficient to generate a flow in the reverse direction during maintenance and the like while preventing a reverse flow during normal circulation.

  The invention according to claim 11 is characterized in that, in order to achieve the object, the common supply channel has a protrusion on a surface facing a communication port communicating with each of the individual supply channels. A droplet discharge head according to any one of 1 to 10 is provided.

  According to the present invention, the common supply channel is formed with a protrusion on the surface facing the communication port communicating with each individual supply channel. Thereby, it is possible to make it easier for the liquid to flow from the common supply channel to the individual supply channel.

  In the invention according to claim 12, in order to achieve the above object, the protrusion is formed such that a surface located on the upstream side is inclined with respect to the liquid flow direction of the liquid flowing through the common supply flow path. A droplet discharge head according to claim 11 is provided.

  According to the present invention, the protrusion is formed such that the surface located on the upstream side is inclined with respect to the liquid flow direction of the liquid flowing through the common supply channel. Thereby, it can prevent that foreign materials, such as a bubble, remain in a protrusion part.

  According to the present invention, it is possible to generate a flow in the reverse direction during maintenance or the like while preventing a reverse flow during normal circulation.

Plane perspective view of the nozzle surface of the first embodiment of the droplet discharge head Longitudinal sectional view showing the schematic structure inside the droplet discharge head 3-3 sectional view of FIG. 4-4 sectional view of FIG. Schematic configuration diagram of a liquid supply system to be supplied to a droplet discharge head Sectional drawing which shows other embodiment (1) of a separate supply flow path and a separate collection flow path Sectional drawing which shows other embodiment (2) of a separate supply flow path and a separate collection flow path Sectional drawing which shows other embodiment (3) of a separate supply flow path and a separate collection flow path Sectional drawing which shows other embodiment (4) of a separate supply flow path and a separate collection flow path Sectional drawing which shows other embodiment (5) of a separate supply flow path and a separate collection flow path Sectional drawing which shows other embodiment of a separate supply flow path and a separate collection flow path Longitudinal sectional view showing a schematic structure inside the second embodiment of the droplet discharge head 13-13 sectional view of FIG. 14-14 sectional view of FIG. Sectional drawing which shows other embodiment of a separate supply flow path and a separate collection flow path Longitudinal sectional view showing the schematic structure inside the third embodiment of the droplet discharge head 17-17 sectional view of FIG. 18-18 sectional view of FIG. Sectional drawing which shows other embodiment of an individual supply flow path Sectional drawing which shows other embodiment of an individual collection flow path

  Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

<< First Embodiment >>
<Configuration of head>
FIG. 1 is a plan perspective view of a nozzle surface of a first embodiment of a droplet discharge head according to the present invention.

  As shown in the figure, the droplet discharge head 10 of the present embodiment is a matrix head in which nozzles 12 are arranged in a two-dimensional matrix.

  The nozzles 12 have one row of nozzles 12 arranged along a straight line inclined at a predetermined angle (θ) with respect to the longitudinal direction of the head as a unit, and many rows of nozzles 12 are arranged in parallel at a constant pitch along the longitudinal direction of the head. Arranged.

  In such a matrix head, the substantial interval between the nozzles 12 projected in the longitudinal direction of the head (the direction orthogonal to the medium conveyance direction) can be reduced, and the density of the nozzles 12 can be increased.

  The droplet discharge head 10 of the present embodiment is a circulation type droplet discharge head 10 that circulates and supplies a liquid to the pressure chamber 14 of each nozzle 12, and supplies the liquid to the pressure chamber 14. A flow path 20 and a recovery flow path 30 for recovering the liquid from the pressure chamber 14 are provided.

  The supply channel 20 further branches from a supply channel main stream 22, a plurality of supply channel tributaries (common supply channels) 24 formed by branching from the supply channel main stream 22, and the supply channel branch 24. And a plurality of individual supply channels 26 formed in the same manner.

  The supply flow path main flow 22 is disposed along the longitudinal direction of the head. A liquid supply port 28 communicates with the supply channel main flow 22, and the liquid is supplied from the liquid supply port 28 to the inside.

  The supply channel tributary 24 is provided for each row of nozzles 12 arranged along a straight line inclined at a predetermined angle with respect to the longitudinal direction of the head, and is arranged in parallel with the row of nozzles 12.

  The individual supply channel 26 is a channel that connects the pressure chambers 14 arranged along the supply channel tributary 24 and the supply channel tributary 24, and is provided for each pressure chamber 14.

  The recovery channel 30 is further branched from a recovery channel main stream 32, a plurality of recovery channel tributaries (common recovery channels) 34 formed by branching from the recovery channel main stream 32, and the recovery channel tributary 34. And a plurality of individual recovery passages 36 formed in this manner.

  The recovery flow path main flow 32 is arranged along the longitudinal direction of the head. A liquid recovery port 38 communicates with the recovery flow path main stream 32, and the internal liquid is recovered from the liquid recovery port 38.

  The recovery flow path tributary 34 is provided for each row of nozzles 12 arranged along a straight line inclined at a predetermined angle with respect to the longitudinal direction of the head, and is arranged in parallel with the row of nozzles 12.

  The individual recovery channel 36 is a channel that connects the pressure chambers 14 arranged along the recovery channel tributary 34 and the recovery channel tributary 34, and is provided for each pressure chamber 14.

  FIG. 2 is a longitudinal sectional view showing a schematic structure inside the droplet discharge head. 3 and 4 are a 3-3 sectional view and a 4-4 sectional view of FIG. 2, respectively.

  As shown in the figure, the droplet discharge head 10 is mainly composed of a nozzle plate 40, a pressure chamber plate 42, a vibration plate 44, and a pressure chamber upper plate 46.

  The nozzle plate 40 is composed of a rectangular substrate having a predetermined thickness, and is arranged in the lowermost layer. The nozzle 12 is formed on the nozzle plate 40. In this example, a tapered nozzle is formed, but the shape of the nozzle is not limited to this.

  The pressure chamber plate 42 is formed of a rectangular substrate having a predetermined thickness, and is disposed on the nozzle plate 40. In the pressure chamber plate 42, a pressure chamber 14 is formed corresponding to each nozzle 12 formed in the nozzle plate 40, and an individual supply channel 26 and an individual recovery channel 36 communicating with each pressure chamber 14 are provided. It is formed. In addition, the pressure chamber plate 42 includes a supply channel branch 24 that communicates with the individual supply channels 26, a supply channel main stream 22 (not shown) that communicates with the supply channel branch 24, and A recovery channel branch 34 that communicates with each individual recovery channel 36 and a recovery channel main stream 32 (not shown) that communicates with the recovery channel branch 34 are formed.

  The pressure chamber 14 is formed in a rectangular cross section, and the nozzle 12 is disposed at the center thereof. In addition, the shape of the pressure chamber 14 is not limited to this, For example, it can also form in cross-sectional circle shape. Further, the arrangement of the nozzles 12 is not necessarily centered, and for example, the nozzle 12 can be arranged at a corner or the like.

  The pressure chamber 14 is formed to penetrate the pressure chamber plate 42, and the nozzle plate 40 is attached to the pressure chamber plate 42, so that the opened lower surface portion is covered with the nozzle plate 40. Further, by attaching the diaphragm 44 to the pressure chamber plate 42, the opened upper surface portion is covered with the diaphragm 44.

  The supply flow path tributary 24 is arranged along the arrangement of the pressure chambers 14 arranged at a constant pitch (an arrangement for each unit). The supply flow path branch 24 is formed as a groove having a certain depth and certain width on the upper surface of the pressure chamber plate 42, and is opened by the diaphragm 44 when the diaphragm 44 is attached to the pressure chamber plate 42. The upper surface part is covered.

  The recovery channel tributaries 34 are also arranged along the arrangement of the pressure chambers 14 (an arrangement for each unit) arranged at a constant pitch. This recovery flow path tributary 34 is formed as a groove having a certain depth and certain width on the lower surface of the pressure chamber plate 42, and the nozzle plate 40 is attached to the pressure chamber plate 42, so that the opened lower surface portion is formed. Covered by the nozzle plate 40.

  The supply channel tributary 24 and the recovery channel tributary 34 are formed in the same shape and are arranged symmetrically with the pressure chamber 14 in between.

  The individual supply channel 26 is formed to extend horizontally from the pressure chamber 14 toward the supply channel branch 24, and communicates the pressure chamber 14 with the supply channel branch 24. The individual supply channel 26 is designed to have a large inertance, and is formed as a groove having a predetermined width on the upper surface of the pressure chamber plate 42. In particular, as shown in FIG. 2, the individual supply flow path 26 of the present embodiment is formed such that the bottom 26 </ b> A is inclined, and its cross-sectional area gradually decreases from the supply flow path branch 24 toward the pressure chamber 14. Formed into a so-called tapered flow path. In this way, by forming the cross-sectional area so as to gradually decrease from the supply flow path branch 24 toward the pressure chamber 14, the individual supply flow path 26 has its flow resistance from the supply flow path branch 24 to the pressure chamber 14. The backflow is effectively suppressed.

  In the individual supply flow path 26 formed in this way, the diaphragm 44 is attached to the pressure chamber plate 42, so that the opened upper surface portion is covered with the diaphragm 44.

  The individual recovery channel 36 is formed to extend horizontally from the pressure chamber 14 toward the recovery channel tributary 34, and communicates the pressure chamber 14 and the recovery channel tributary 34. The individual recovery flow path 36 is also designed to have a large inertance, and is formed as a groove having a predetermined width on the upper surface of the pressure chamber plate 42. In particular, as shown in FIG. 2, the individual recovery channel 36 of the present embodiment is formed such that the top surface portion 36 </ b> A is inclined, and the cross-sectional area gradually decreases from the pressure chamber 14 toward the recovery channel tributary 34. (So-called tapered flow path). Thus, by forming the cross-sectional area so as to gradually decrease from the pressure chamber 14 toward the recovery flow path tributary 34, the individual recovery flow path 36 has its flow resistance from the pressure chamber 14 to the recovery flow path tributary 34. The backflow is effectively suppressed.

  The individual recovery flow path 36 formed in this way is attached to the pressure chamber plate 42 by the nozzle plate 40, so that the opened lower surface portion is covered with the nozzle plate 40.

  The diaphragm 44 is formed in a rectangular thin plate shape having a predetermined thickness, and is disposed on the pressure chamber plate 42. As described above, the pressure chamber 14 is closed at the ceiling portion by arranging the diaphragm 44. That is, the diaphragm 44 constitutes the ceiling surface of the pressure chamber 14.

  A piezoelectric element 48 is disposed on the vibration plate 44 in correspondence with the position of each pressure chamber 14. Each pressure chamber 14 is driven to drive the piezoelectric element 48 so that the ceiling surface is displaced and the volume is expanded and contracted. As a result, the liquid in the pressure chamber 14 is discharged as droplets from the nozzle 12.

  The pressure chamber upper plate 46 is formed in a rectangular plate shape having a predetermined thickness, and is disposed on the vibration plate 44. A rectangular space 50 is formed in the pressure chamber upper plate 46 corresponding to the piezoelectric element 48 provided on the vibration plate 44. Each piezoelectric element 48 provided on the vibration plate 44 is accommodated in a space 50 formed in the pressure chamber upper plate 46 when the pressure chamber upper plate 46 is attached to the vibration plate 44. Thereby, the piezoelectric element 48 is attached to be displaceable.

<Liquid supply system>
-System configuration-
First, the overall configuration of the system will be outlined.

  FIG. 5 is a schematic configuration diagram of a liquid supply system supplied to the droplet discharge head.

  The main tank 100 is connected to the buffer tank 104 via the main tank connection pipe 102. The main tank connection pipe 102 is provided with a main pump 106 and a main valve 108.

  The main pump 106 operates in response to a command from a control device (not shown), and sends the liquid stored in the main tank 100 to the buffer tank 104.

  The main valve 108 operates in response to a command from the control device, and opens and closes the main tank connection pipe 102.

  The buffer tank 104 is open to the atmosphere through an open air hole 104A formed on the top surface. A predetermined amount of liquid is stored in the buffer tank 104 by the liquid supplied from the main tank 100.

  The buffer tank 104 is communicated with the supply tank 112 via the first supply channel 110, and the supply tank 112 is communicated with the liquid supply port 28 of the droplet discharge head 10 via the second supply channel 114. ing.

  The buffer tank 104 is communicated with the recovery tank 120 via the first recovery flow path 118, and the recovery tank 120 is connected to the liquid recovery port 38 of the droplet discharge head 10 via the second recovery flow path 122. It is communicated to.

  A supply pump 126 and a filter 128 are provided in the first supply flow path 110. The supply pump 126 operates in response to a command from the control device, and sends liquid from the buffer tank 104 to the supply tank 112. The filter 128 is provided between the supply pump 126 and the buffer tank 104 and removes impurities from the liquid supplied to the supply tank 112.

  A supply valve 130 is provided in the second supply channel 114. The supply valve 130 operates in response to a command from the control device, and opens and closes the second supply flow path 114.

  A recovery pump 132 is provided in the first recovery channel 118. The recovery pump 132 operates in response to a command from the control device, and sends liquid from the recovery tank 120 to the buffer tank 104.

  A recovery valve 134 is provided in the second recovery flow path 122. The collection valve 134 operates according to a command from the control device, and opens and closes the second supply flow path 114.

  The inside of the supply tank 112 is partitioned into a supply liquid chamber 112A and a supply gas chamber 112B by an elastic film 136. A first supply channel 110 and a second supply channel 114 are communicated with the supply liquid chamber 112A. The liquid supplied from the buffer tank 104 via the first supply channel 110 is temporarily stored in the supply liquid chamber 112A. Then, it is supplied from the supply liquid chamber 112 </ b> A to the droplet discharge head 10 via the second supply flow path 114. The supply liquid chamber 112A has its internal pressure detected by the supply pressure detector 138, and the detection result is output to the control device.

  On the other hand, the supply gas chamber 112B is filled with gas. The supply gas chamber 112B communicates with an atmosphere release pipe 140 for opening the supply gas chamber 112B to the atmosphere. The atmosphere release pipe 140 is provided with an atmosphere release valve 142. The atmosphere release valve 142 operates in response to a command from the control device, and opens and closes the atmosphere release pipe 140.

  The configuration of the recovery tank 120 is the same. That is, the inside is partitioned into the recovery liquid chamber 120A and the recovery gas chamber 120B by the elastic film 144.

  A first recovery channel 118 and a second recovery channel 122 are communicated with the recovery liquid chamber 120A. The liquid recovered from the droplet discharge head 10 via the second recovery flow path 122 is temporarily stored in the recovery liquid chamber 120A. Then, the liquid is recovered from the recovery liquid chamber 120 </ b> A to the buffer tank 104 via the first recovery flow path 118. The recovery liquid chamber 120A has its internal pressure detected by a recovery pressure detector 146, and the detection result is output to the control device.

  On the other hand, the recovery gas chamber 120B is filled with gas. The recovery gas chamber 120B communicates with an atmosphere release pipe 148 for opening the recovery gas chamber 120B to the atmosphere. The atmosphere release pipe 148 is provided with an atmosphere release valve 150. The atmosphere release valve 150 operates in response to a command from the control device, and opens and closes the atmosphere release pipe 148.

-Liquid supply operation-
Next, the operation of circulating and supplying the liquid will be described.

  At the time of circulating supply, the air release valve 142 that opens the supply gas chamber 112B of the supply tank 112 to the atmosphere and the air release valve 150 that opens the recovery gas chamber 120B of the recovery tank 120 to the atmosphere are closed. On the other hand, the liquid is recovered from the supply liquid chamber 112A of the supply tank 112 to the droplet discharge head 10 to the supply valve 130 of the second supply flow path 114 and from the droplet discharge head 10 to the recovery liquid chamber 120A of the recovery tank 120. The recovery valves 134 of the second recovery flow path 122 are each opened.

  In the supply system of this example, by setting the pressure on the supply side higher than the pressure on the recovery side by a predetermined amount, the liquid is sent from the supply tank 112 side to the recovery tank 120 side via the droplet discharge head 10. . Specifically, the internal pressure of the supply liquid chamber 112A is Pin, the internal pressure of the recovery liquid chamber 120A is Pout, the back pressure (negative pressure) of the nozzle is Pn, and the height between the liquid discharge surface and the supply pressure detector 138 is high or low. If the pressure difference (water head pressure) caused by the difference is Hin and the pressure difference (water head pressure) caused by the height difference between the liquid ejection surface and the recovery pressure detector 146 is Hout, then Pin + Hin> Pn> Pout + Hout (mmH2O) A predetermined back pressure is applied to the nozzle.

  Based on the internal pressure of the supply liquid chamber 112 </ b> A detected by the supply pressure detector 138 and the internal pressure of the recovery liquid chamber 120 </ b> A detected by the recovery pressure detector 146, the control device controls the supply pump 126 and the recovery pump 132. And the internal pressure of the supply liquid chamber 112A and the internal pressure of the recovery liquid chamber 120A are controlled to predetermined pressures Pin and Pout, respectively. Thereby, the liquid is circulated and supplied to the droplet discharge head 10.

  Even when a pressure fluctuation occurs due to the operation of the supply pump 126 and the recovery pump 132, the pressure is absorbed by the elastic film 136 provided in the supply tank 112 and the elastic film 144 provided in the recovery tank 120. The pressure fluctuation in the nozzle 12 can be suppressed. Thereby, the back pressure of the nozzle 12 can always be maintained constant.

  The circulation supply operation of the liquid is always performed even during the operation (printing) of the droplet discharge head 10, thereby suppressing the thickening of the liquid discharged from the nozzle 12.

<Action of droplet discharge head>
As described above, the liquid (for example, ink) discharged from the nozzle 12 is circulated and supplied to the droplet discharge head 10.

  The liquid from the supply tank 112 to the liquid supply port 28 first flows through the supply flow path main flow 22. Then, it flows from the supply flow channel main flow 22 to the supply flow channel tributary (common supply flow channel) 24, and is supplied from the supply flow channel tributary 24 to each pressure chamber 14 via the individual supply flow channel 26.

  The liquid supplied to the pressure chamber 14 is discharged from the nozzle 12 by driving the piezoelectric element 48.

  In addition to the operation of the piezoelectric element 48, due to the pressure difference between the supply channel 20 and the recovery channel 30, the liquid in the pressure chamber 14 flows through the individual recovery channel 36 through the recovery channel tributary (common recovery flow). Road) 34. The liquid that has flowed to the recovery flow path tributary 34 flows to the recovery flow path main flow 32 and is recovered to the recovery tank 120 via the liquid recovery port 38.

  Thus, the liquid discharged from the nozzle 12 is circulated and supplied to the pressure chamber 14.

  By the way, in such a circulation type droplet discharge head 10, when a liquid flows in a direction opposite to the direction intended at the time of discharge or the like, not only the liquid is not refreshed but also a bubble discharge flow when bubbles are mixed. Therefore, there is a problem that the bubbles cannot be removed and the discharge becomes impossible. In addition, the occurrence of an asymmetric flow also affects the surrounding nozzles that have been normally circulated.

  However, in the liquid droplet ejection head 10 of the present embodiment, the individual supply flow channel 26 communicated with the pressure chamber 14 is formed so that the cross-sectional area gradually decreases toward the pressure chamber 14, and the individual recovery flow Since the path 36 is formed so that the cross-sectional area gradually decreases toward the recovery flow path tributary 34, backflow can be effectively prevented. That is, by forming the cross-sectional area of the individual supply channel 26 so as to gradually decrease from the common channel tributary 24 toward the pressure chamber 14, the channel resistance increases from the common channel tributary 24 toward the pressure chamber 14. Thus, backflow (flow from the pressure chamber 14 toward the common flow path branch 24) can be effectively prevented. Further, by forming the cross-sectional area of the individual recovery channel 36 so as to gradually decrease from the pressure chamber 14 toward the recovery channel tributary 34, the channel resistance increases from the pressure chamber 14 toward the recovery channel tributary 34. Thus, backflow (flow from the recovery flow path tributary 34 toward the pressure chamber 14) can be effectively prevented.

  On the other hand, during maintenance, the liquid may be intentionally circulated in the reverse direction. However, the droplet discharge head 10 of the present embodiment is not configured to allow the flow in the reverse direction at all. Accordingly, it is possible to cause the liquid to flow in the direction opposite to that during normal operation (printing).

  Thus, according to the droplet discharge head 10 of the present embodiment, in normal circulation, it is possible to generate a flow in the reverse direction while preventing a reverse flow and during maintenance. As a result, it is possible to suppress unintended refills and the accompanying occurrence of crosstalk. Further, since the liquid flow direction is one direction, a local loop does not occur, and bubbles, foreign matter, and deteriorated liquid can be discharged smoothly.

  Furthermore, since a special mechanism such as a check valve is not required, the configuration can be made simple and compact. Therefore, it is particularly effective for an ink jet head composed of micro flow paths (100 μm or less).

  In addition, since no movable structure is involved, it is possible to discharge liquid droplets with high durability and stable for a long period of time.

<Other forms of individual supply channel and individual recovery channel>
In the liquid droplet ejection head 10 of the above-described embodiment, the individual supply channel 26 is formed in a tapered shape by forming the bottom portion 26A of the individual supply channel 26 linearly inclined from the inlet portion toward the outlet portion. However, the cross-sectional area is formed so as to gradually decrease from the common flow path tributary 24 toward the pressure chamber 14, but the mode of changing the cross-sectional area of the individual supply flow path 26 is not limited to this. Absent. The same applies to the individual recovery flow path 36.

  FIG. 6 is a cross-sectional view showing another embodiment (1) of the individual supply channel and the individual recovery channel.

  As shown in the figure, in this example, the individual supply channel 26 is formed such that its bottom 26A is formed in a step shape from the inlet to the outlet, so that the cross-sectional area gradually decreases. (It is a so-called stepped tapered channel.)

  Further, as shown in the figure, the individual recovery flow path 36 is formed such that its top surface portion 36A is formed in a step shape from the inlet portion to the outlet portion, so that the cross-sectional area gradually decreases ( It is a so-called stepped tapered flow path.)

  As described above, the aspect of changing the cross-sectional area is not necessarily continuous, and may be changed stepwise. Further, it is not always necessary to change linearly, and it may be changed in a curved manner.

  FIG. 7 is a cross-sectional view showing another embodiment (2) of the individual supply channel and the individual recovery channel.

  As shown in the figure, in this example, the individual supply channel 26 is formed such that a part of the bottom portion 26A is inclined in the middle so that the cross-sectional area gradually decreases in the middle. (In the example shown in the figure, the inlet and outlet are formed to have a constant size and gradually decrease in the middle.)

  Further, as shown in the figure, the individual recovery channel 36 is formed such that a part of the top surface portion 36A is inclined in the middle so that the cross-sectional area gradually decreases in the middle ( In the example shown in the figure, the inlet and outlet portions are formed with a constant size and are formed so as to gradually decrease in the middle).

  In this way, the portion where the cross-sectional area is changed does not necessarily have to be the entire flow path, and only a part may be reduced.

  FIG. 8 is a cross-sectional view showing another embodiment (3) of the individual supply channel and the individual recovery channel.

  As shown in the figure, in this example, the individual supply channel 26 is formed so that the cross-sectional area gradually decreases as the side wall surfaces 26B of both sides thereof are inclined.

  Further, as shown in FIG. 5B, the individual recovery flow path 36 is also formed so that the cross-sectional area gradually decreases by forming the side wall surfaces 36B of both sides to be inclined.

  As described above, the wall surface inclined (including stepped shape) to reduce the cross-sectional area is not limited to the bottom portion or the top surface portion, and the side wall surface portion may be inclined. Further, the inclined wall surface does not necessarily have to be a single surface, and all four surfaces may be inclined.

  In consideration of ease of processing, when the flow path is formed as a groove on the upper surface of the substrate (in this example, the pressure chamber plate 42) (individual supply flow path 26 in this example), the bottom or It is preferable to incline the side wall surface portion. On the other hand, when the flow path is formed as a groove on the lower surface of the substrate (corresponding to the individual recovery flow path 36 in this example), it is preferable to incline the top surface portion or the side wall surface portion. In this case, when the substrate is silicon, it can be easily formed by etching or the like. Moreover, when a board | substrate is a SUS material, it can form easily by increasing the number of lamination | stacking. The processing can also be performed later with a laser or the like.

  Further, the cross-sectional shapes of the individual supply channel 26 and the individual recovery channel 36 are not necessarily rectangular, and can be formed in a circular shape in addition to a polygonal shape.

  In the above embodiment, the individual supply channel 26 is communicated with the top surface side of the pressure chamber 14 and the individual recovery channel 36 is communicated with the bottom surface side of the pressure chamber 14. It can also be set as the structure connected.

  FIG. 9 is a cross-sectional view showing another embodiment (4) of the individual supply channel and the individual recovery channel.

  As shown in the figure, in this example, the individual supply channel 26 is formed in a curved shape, and is formed so that the cross-sectional area gradually decreases by inclining the bottom.

  Further, as shown in FIG. 4B, the individual recovery flow path 36 is also formed in a curved shape, and is formed so that the cross-sectional area gradually decreases by inclining the bottom.

  As described above, the individual supply channel 26 and the individual recovery channel 36 are not necessarily formed linearly, and may be formed curved. Thus, by curving the individual supply channel 26 and the individual recovery channel 36, the channel length can be secured to a desired length while achieving compactness in the width direction.

  In this example, the cross-sectional area is gradually decreased by inclining the bottom of the flow path. However, the cross-sectional area may be gradually decreased by gradually decreasing the distance between the wall surfaces on both sides.

  FIG. 10 is a cross-sectional view showing another embodiment (5) of the individual supply channel and the individual recovery channel.

  As shown in the figure, in this example, the supply flow path branch 24 and the recovery flow path branch 34 are formed in the pressure chamber upper plate 46.

  The individual supply channel 26 is formed in an L-shape composed of a vertical portion 26V and a horizontal portion 26H, and is formed so that the cross-sectional area of the horizontal portion 26H gradually decreases (the top surface portion 26HA of the horizontal portion 26H is inclined). By doing so, the cross-sectional area of the horizontal portion 26H is formed so as to gradually decrease.

  The individual recovery flow path 36 is also formed in an L shape including a vertical portion 36V and a horizontal portion 36H, and is formed so that the cross-sectional area of the horizontal portion 36H gradually decreases (the top surface portion 36HA of the horizontal portion 36H is inclined). Thus, the cross-sectional area of the horizontal portion 36H is formed so as to gradually decrease.)

  As described above, the individual supply channel 26 and the individual recovery channel 36 may be bent. In this case, as in this example, only a partial cross-sectional area of the flow path may be gradually reduced.

  Further, when reducing the cross-sectional area of a part of the flow path, the cross-sectional area of the horizontal portion may be gradually decreased as in this example, or the vertical portion may be reduced as shown in FIG. The cross-sectional area may be gradually decreased. Further, as a whole, the cross-sectional area may be formed so as to gradually decrease.

  As described above, various modes can be adopted for changing the cross-sectional areas of the individual supply flow channel 26 and the individual recovery flow channel 36.

  In order to obtain a sufficient effect, the individual supply flow channel 26 has a cross-sectional area Sin at the inlet (a communication portion with the supply flow channel tributary 24) and a cross-sectional area at the outlet (a communication portion with the pressure chamber 14). It is preferable to set the ratio (Sin / Sout) with Sout to be 110% or more. Similarly, the ratio (Rin) between the cross-sectional area Rin of the inlet part (communication part with the pressure chamber 14) and the cross-sectional area Rout of the outlet part (communication part with the recovery flow path tributary 34) also for the individual recovery flow path 36. / Rout) is preferably set to be 110% or more.

<< Second Embodiment >>
FIG. 12 is a longitudinal sectional view showing a schematic structure of the interior of the second embodiment of the droplet discharge head. FIGS. 13 and 14 are a sectional view taken along line 13-13 and a sectional view taken along line 14-14 in FIG. 12, respectively.

  As shown in the figure, the droplet discharge head 10A of the present embodiment is mainly provided with a supply projection 24A in a supply channel tributary (common supply channel) 24 and a recovery channel tributary (common recovery channel) 34. And the recovery projection 34A is different from the droplet discharge head 10 of the first embodiment described above.

  Therefore, here, only the configuration and operational effects of the supply protrusion 24A and the recovery protrusion 34A will be described.

  The supply protrusion 24 </ b> A is provided at a communication portion of each individual supply channel 26 and functions as a trap for the liquid flowing in the supply channel tributary 24. The supply protrusion 24 </ b> A is formed on the surface facing the wall surface with which the individual supply channel 26 communicates, and is formed facing the communication port of the individual supply channel 26.

  The recovery projection 34A is provided in a communication portion of each individual recovery flow path 36. The recovery projection 34A is formed on the wall surface with which the individual recovery channel 36 communicates, and is formed on the upstream side of the communication port of the individual recovery channel 36.

  By forming the supply protrusion 24A in the supply flow path branch 24, the liquid flowing in the supply flow path branch 24 can easily flow into the individual supply flow path 26. Thereby, the backflow to the direction which is not intended can be suppressed more effectively.

  Similarly, by forming the recovery projection 34A as described above in the recovery flow path tributary 34, the liquid flowing through the individual recovery flow path 36 can easily flow into the recovery flow path tributary 34. Thereby, the backflow to the direction which is not intended can be suppressed more effectively.

  The shapes of the supply protrusion 24A and the recovery protrusion 34A are not particularly limited, but can be smoothly formed by forming a triangular cross section with the upstream surface inclined with respect to the liquid flow as in this example. Can be formed, and foreign substances such as bubbles can be prevented from staying.

  In addition, as in this example, by forming a triangular cross section, it is possible to easily perform processing and to ensure strength.

  In addition, as the shapes of the supply protrusion 24A and the recovery protrusion 34A, for example, as shown in FIG. 15, they can be formed as plate-like protrusions.

  Further, these protrusions can be formed by etching or the like when the substrate is silicon, and can be formed by increasing the number of layers when the substrate is SUS material. Processing can also be performed with a laser or the like.

<< Third Embodiment >>
FIG. 16 is a longitudinal sectional view showing a schematic structure of the inside of the third embodiment of the droplet discharge head. FIGS. 17 and 18 are a 17-17 sectional view and an 18-18 sectional view of FIG. 16, respectively.

  As shown in the figure, in the droplet discharge head 10B of the present embodiment, the inlet portion of the individual supply channel 26 is chamfered and the outlet portion of the individual recovery channel 36 is a recovery channel tributary (common). This is different from the liquid droplet ejection head 10 of the first embodiment described above in that it is formed so as to protrude to the recovery flow path 34.

  Therefore, here, only the configuration and operational effects of the individual supply channel 26 and the individual recovery channel 36 will be described.

  As shown in FIG. 17, the individual supply channel 26 is formed straight from the supply channel tributary 24 toward the pressure chamber 14 except for the inlet portion 26 </ b> P with a constant cross-sectional area. The inlet portion 26P (the portion of the communication port communicating with the supply flow path branch 24) is chamfered at both left and right edge portions with a predetermined chamfer length and chamfer angle.

  On the other hand, as shown in FIG. 18, the individual recovery channel 36 is formed straight from the pressure chamber 14 toward the recovery channel tributary 34 with a constant cross-sectional area, and communicates with the outlet 36P (the recovery channel tributary 34). A communication port portion) is formed so as to protrude by a predetermined amount in the recovery flow path tributary 34.

  Thus, by chamfering the left and right peripheral edges of the inlet portion 26P of the individual supply channel 26, the liquid flowing through the supply channel tributary 24 can easily flow into the individual supply channel 26. Thereby, the backflow to the direction which is not intended can be suppressed effectively.

  Similarly, by causing the outlet portion 36 </ b> P of the individual recovery flow path 36 to protrude into the recovery flow path tributary 34, the liquid flowing through the individual recovery flow path 36 can easily flow into the recovery flow path tributary 34. Thereby, the backflow to the direction which is not intended can be suppressed effectively.

  As described above, also in the droplet discharge head 10B of the present embodiment, in normal circulation, it is possible to generate a flow in the reverse direction while preventing a reverse flow and during maintenance. As a result, it is possible to suppress unintended refills and the accompanying occurrence of crosstalk. Further, since the liquid flow direction is one direction, a local loop does not occur, and bubbles, foreign matter, and deteriorated liquid can be discharged smoothly.

  The processing applied to the individual supply channel 26 and the individual recovery channel 36 can be formed by etching or the like when the substrate is silicon, and is formed by increasing the number of layers when the substrate is SUS material. be able to. Further, the processing can also be performed with a laser or the like.

  In order to obtain a sufficient effect, the chamfer formed at the inlet portion 26P of the individual supply channel 26 has a chamfer length Lc of 5% or more with respect to the width Ls of the common channel tributary 24, 20 ° to 70 °. Preferably, the chamfer angle α is formed. Further, it is preferable that the protruding amount x of the outlet portion 36P of the individual recovery flow path 36 is projected to the recovery flow path tributary 34 with a length of 5% or more with respect to the width Lr of the recovery flow path tributary 34.

  Further, in this example, the individual supply channel 26 is formed with a constant cross-sectional area except for the inlet portion 26P, but the cross-sectional area toward the pressure chamber 14 is increased as in the first embodiment described above. You may form so that it may reduce gradually. Similarly, the sectional area of the individual recovery channel 36 may be formed so as to gradually decrease from the pressure chamber 14 toward the recovery channel tributary 34.

  Also in this example, the individual supply flow channel 26 and the individual recovery flow channel 36 can be formed to be bent or curved.

<Other forms of individual supply channel and individual recovery channel>
FIG. 19 is a cross-sectional view showing another embodiment of the individual supply channel.

  As shown in the figure, the chamfering applied to the inlet portion 26P of the individual supply flow path 26 is performed by chamfering only the edge of the side located on the upstream side with respect to the flow direction of the liquid flowing through the supply flow path tributary 24. You may do it.

  Further, as shown in the figure, a supply protrusion 24A may be formed in the supply flow path branch 24. As a result, the liquid flowing through the supply flow path tributary 24 can easily flow into the individual supply flow path 26.

  FIG. 20 is a cross-sectional view showing another embodiment of the individual recovery channel.

  As shown in the figure, the outlet part 36P of the individual recovery channel 36 projects only the channel wall on the upstream side with respect to the flow direction of the liquid flowing through the recovery channel tributary 34. May be.

  In addition, as shown to the figure, it is preferable that the exit part 36P of the separate collection | recovery flow path 36 made to project is formed in a taper shape by inclining the outer periphery. Thereby, it can prevent that foreign materials, such as a bubble, remain in a protrusion part. Further, the strength can be ensured.

  DESCRIPTION OF SYMBOLS 10 ... Droplet discharge head (1st Embodiment), 10A ... Droplet discharge head (2nd Embodiment), 10B ... Droplet discharge head (3rd Embodiment), 10 ... Nozzle, 14 DESCRIPTION OF SYMBOLS ... Pressure chamber, 20 ... Supply flow path, 22 ... Supply flow path main flow, 24 ... Supply flow path tributary (common supply flow path), 24A ... Supply protrusion, 26 ... Individual supply flow path, 26A ... Individual supply flow path 26B ... Individual supply flow path side wall surface, 26V ... Individual supply flow path vertical section, 26H ... Individual supply flow path horizontal section, 26HA ... Individual supply flow path horizontal section top surface section, 26 ... Individual supply Inlet part of channel, 28 ... liquid supply port, 30 ... recovery channel, 32 ... main channel of recovery channel, 34 ... tributary of recovery channel (common recovery channel), 34A ... projection for recovery, 36 ... individual recovery flow Road, 36A ... Top surface portion of individual recovery channel, 36B ... Side wall surface of individual recovery channel, 36V ... Individual recovery Vertical portion of path, 36H: Horizontal portion of individual recovery flow path, 36HA: Top surface portion of horizontal portion of individual recovery flow path, 36P: Exit portion of individual recovery flow path, 38 ... Liquid recovery port, 40 ... Nozzle plate, 42 ... pressure chamber plate, 44 ... vibration plate, 46 ... pressure chamber upper plate, 48 ... piezoelectric element, 50 ... space, 100 ... main tank, 102 ... main tank connection piping, 104 ... buffer tank, 104A ... air release hole, 102 ... main tank connection pipe, 106 ... main pump, 108 ... main valve, 110 ... first supply flow path, 112 ... supply tank, 112A ... supply liquid chamber, 112B ... supply gas chamber, 114 ... second supply flow path, 118 ... 1st recovery flow path, 120 ... Recovery tank, 120A ... Recovery liquid chamber, 120B ... Recovery gas chamber, 122 ... 2nd recovery flow path, 126 ... Supply pump, 128 ... Fi 130 ... Supply valve, 132 ... Recovery pump, 134 ... Recovery valve, 136 ... Elastic membrane, 138 ... Supply pressure detector, 140 ... Air release pipe, 142 ... Air release valve, 144 ... Elastic membrane, 146 ... Recovery pressure Detector, 148 ... Air release pipe, 150 ... Air release valve

Claims (12)

A plurality of pressure chambers arranged in parallel, a common supply channel arranged along the arrangement of the pressure chambers, a common recovery channel arranged along the arrangement of the pressure chambers, and the pressure chambers A plurality of individual supply channels that individually communicate with the common supply channel, and a plurality of individual recovery channels that individually communicate each of the pressure chambers with the common recovery channel, via the pressure chambers In the liquid droplet ejection head that generates a flow from the common supply channel to the common recovery channel and supplies the liquid to the pressure chamber,
Each individual supply channel is formed such that a cross-sectional area gradually decreases from the common supply channel toward the pressure chamber,
Each of the individual recovery channels is formed so that a cross-sectional area gradually decreases from the pressure chamber toward the common recovery channel. Each individual supply channel is formed such that at least one surface of the channel wall is inclined, so that the cross-sectional area gradually decreases from the common supply channel toward the pressure chamber,
Each of the individual recovery channels is formed so that a cross-sectional area gradually decreases from the pressure chamber toward the common recovery channel by forming at least one surface of the channel wall inclined. The droplet discharge head according to claim 1, wherein Each of the individual supply channels is formed such that the ratio of the cross-sectional area of the communication port communicating with the common supply channel and the cross-sectional area of the communication port communicating with the pressure chamber is 110% or more.
Each of the individual recovery channels is formed so that a ratio of a cross-sectional area of the communication port communicating with the pressure chamber and a cross-sectional area of the communication port communicating with the common recovery channel is 110% or more. The liquid droplet ejection head according to claim 1, wherein the liquid droplet ejection head is a liquid ejection head. Each individual supply channel is chamfered at the edge of the communication port communicating with the common supply channel,
Each said individual collection flow path is formed so that the edge part of the communication port connected to the said common collection flow path may protrude in the said common collection flow path. The droplet discharge head described. A plurality of pressure chambers arranged in parallel, a common supply channel arranged along the arrangement of the pressure chambers, a common recovery channel arranged along the arrangement of the pressure chambers, and the pressure chambers A plurality of individual supply channels that individually communicate with the common supply channel, and a plurality of individual recovery channels that individually communicate each of the pressure chambers with the common recovery channel, via the pressure chambers In the liquid droplet ejection head that generates a flow from the common supply channel to the common recovery channel and supplies the liquid to the pressure chamber,
Each individual supply channel is chamfered at the edge of the communication port communicating with the common supply channel,
Each of the individual recovery flow paths is formed by projecting an edge of a communication port communicating with the common recovery flow path into the common recovery flow path.   6. The edge of the side located on the upstream side of each individual supply channel is chamfered with respect to the liquid flow direction of the liquid flowing through the common supply channel. Droplet discharge head.   Each of the individual recovery channels is formed such that an edge of a side located upstream from the liquid flow direction of the liquid flowing through the common recovery channel protrudes into the common recovery channel. The droplet discharge head according to any one of claims 4 to 6.   The liquid according to any one of claims 4 to 7, wherein each of the individual recovery channels is formed with an outer periphery of an edge formed so as to protrude into the common recovery channel. Drop ejection head.   Each of the individual supply channels has a chamfer formed at an edge of a communication port communicating with the common supply channel with a chamfer length of 5% or more with respect to the width of the common supply channel. The liquid droplet ejection head according to claim 4, wherein the liquid droplet ejection head is formed with a chamfering angle of 20 ° to 70 °.   Each individual recovery channel is formed such that an edge of a communication port communicating with the common recovery channel protrudes into the common recovery channel with a protruding amount of 5% or more with respect to the width of the common recovery channel. The droplet discharge head according to claim 4, wherein the droplet discharge head is formed.   11. The droplet discharge head according to claim 1, wherein the common supply channel has a protrusion on a surface facing a communication port communicating with each individual supply channel.   12. The droplet discharge head according to claim 11, wherein the protrusion is formed such that a surface positioned on the upstream side is inclined with respect to a liquid flow direction of the liquid flowing through the common supply channel.

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