JP2016147431A - Inkjet head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inkjet head that can be cooled without affecting ink flowing therein.SOLUTION: The inkjet head includes: an injection unit 50 having multiple nozzles for ejecting ink that is circulated by being supplied from an ink supply system 201 and discharged from an ink discharge system 202 and an actuator for causing the ink to be ejected from the nozzles; a drive circuit for driving the actuator; and a transmission member 75 that is a member for being connected to an ink discharge tube only and transmits heat generated from the drive circuit to the ink discharge tube.SELECTED DRAWING: Figure 17

Description

  Embodiments described herein relate generally to an inkjet head.

  An ink jet head used in an industrial ink jet printer includes a head having a piezoelectric element for ejecting ink and a driving IC for driving the piezoelectric element of the head. In general, a substrate on which a drive IC is mounted and a substrate on which an electronic component is mounted are housed in a casing from the viewpoint of preventing adhesion of ink and foreign matter.

  The heat generated from the drive IC is released to the outside by using the casing as a heat sink. The larger the casing that functions as the heat sink, the more the heat radiation effect for heat generated from the drive IC can be improved. However, in recent years, due to an increase in the printing rate and printing speed, the load on the driving IC has increased, and the amount of heat generation has increased accordingly. Enlarging the casing is at the limit. Various techniques for efficiently cooling the inkjet head have been proposed.

  In the conventional apparatus, a pipe of ink supplied to the inkjet head is piped to a piezoelectric element of the head, and the head piezoelectric element is cooled by ink.

  However, in the conventional apparatus, heat exchange is performed between the head piezoelectric element and the ink supplied to the inkjet head, and the viscosity of the ink supplied to the inkjet head, which is balanced only by the head piezoelectric element, is There is a risk that the printing quality will be affected by the temperature of the driving IC, resulting in a decrease in print quality.

JP 2013-193212 A

  The present invention has been made under the circumstances described above, and an object of the present invention is to cool an inkjet head without affecting ink flowing into the inkjet head.

  In order to solve the above problems, an inkjet head according to the present embodiment is provided with a plurality of nozzles that discharge ink that is circulated by being supplied from an ink supply pipe and discharged from the ink discharge pipe, and for discharging ink from the nozzles. An ejection unit having an actuator, a drive circuit that drives the actuator, and a transmission member that is connected to only the ink discharge pipe and that transmits heat generated from the drive circuit to the ink discharge system. .

It is a perspective view which shows the inkjet head which concerns on this embodiment. It is a perspective view of a case. It is a perspective view of a case. It is an expansion | deployment perspective view which shows a mask plate, a circulation system, a support unit, an injection unit, and a heat pipe. It is an expansion perspective view of an injection unit. It is an expansion perspective view of an injection unit and a flexible substrate. It is a perspective view of an injection unit, a flexible substrate, and a rigid substrate. It is a development perspective view of a circulation system and a heat pipe. It is an expansion | deployment perspective view of a support unit. It is a figure for demonstrating the assembly procedure of an inkjet head. It is a figure for demonstrating the assembly procedure of an inkjet head. It is a figure for demonstrating the assembly procedure of an inkjet head. It is a figure for demonstrating the assembly procedure of an inkjet head. It is a figure which shows the YZ cross section of an inkjet head. It is a perspective view of an ink conduit. 2 is a perspective view of an ink jet head connected to an ink conduit. FIG. It is a figure which shows the inkjet head connected to the ink pipe line.

  Hereinafter, the present embodiment will be described with reference to the drawings. In the description, an orthogonal coordinate system including an X axis, a Y axis, and a Z axis that are orthogonal to each other is used.

  FIG. 1 is a perspective view showing an inkjet head 10 according to the present embodiment. The ink jet head 10 is an ink jet head connected to an ink conduit. The inkjet head 10 includes a housing 20, a mask plate 41, a support unit 70 accommodated in the housing 20, and two heat pipes 75 as transmission members made of metal.

  As shown in FIG. 1, the housing 20 includes two cases 30 and two covers 40.

  FIG. 2 is a perspective view of the case 30. FIG. 3 is a view of the case 30 in FIG. 2 as viewed from the + Y side. The case 30 is made of aluminum having a relatively high thermal conductivity, for example. As can be seen from FIGS. 2 and 3, the case 30 has two portions: a U-shaped frame portion 31 and an inner wall portion 32 that divides the space surrounded by the frame portion 31 into two spaces 30 a and 30 b. doing.

  The frame part 31 constituting the case 30 is formed across the upper edge of the inner wall part 32 and the edges on both sides in the X-axis direction. A notch 37 is formed at the lower end of the frame portion 31, and a notch 38 is formed at a portion that divides the space 30 b of the frame portion 31.

  In addition, semicircular cutouts 33, 34, 39 reaching the space 30 b are formed on one upper side of the frame portion 31. A notch 36 reaching the space 30a is formed on the other upper side of the frame portion 31.

  Returning to FIG. 1, the cover 40 is a quadrangular plate. Similarly to the case 30, the cover 40 is made of aluminum having a relatively high thermal conductivity.

  4 is an exploded perspective view showing the mask plate 41, the circulation system 60, the support unit 70, the injection unit 50, and the heat pipe 75 that constitute the inkjet head 10. As shown in FIG. As shown in FIG. 4, the mask plate 41 is a frame-like member whose longitudinal direction is the X-axis direction. A protrusion 41 a that protrudes inward is provided at the lower end of the mask plate 41.

  FIG. 5 is a developed perspective view of the injection unit 50. As shown in FIG. 5, the injection unit 50 includes a base substrate 51, a frame 52, and an orifice plate 53.

  The base substrate 51 is a rectangular plate member whose longitudinal direction is the X-axis direction. The base substrate 51 is made of alumina, for example, and a plurality of openings 51a are formed along the X axis at the center in the Y axis direction. A plurality of openings 51b are formed along the X axis on the −Y side and the + Y side of the opening 51a.

  Two actuators 54 and 55 are arranged on the upper surface of the base substrate 51. As shown in FIG. 5, the actuators 54 and 55 are disposed on both sides of the opening 51a in the Y-axis direction.

  The actuators 54 and 55 are composed of trapezoidal piezoelectric elements arranged along the X axis, and a space between the piezoelectric elements is a pressure chamber. The piezoelectric elements constituting the actuators 54 and 55 are connected to an electrode pattern (not shown) formed on the −Z side surface of the base substrate 51.

  The frame 52 is a frame-shaped member whose longitudinal direction is the X-axis direction. The frame 52 is made of, for example, ceramic, alumina, aluminum, or stainless steel. The frame 52 is slightly smaller than the base substrate 51.

  The orifice plate 53 is a rectangular sheet whose material is polyimide and whose longitudinal direction is the X-axis direction. In the orifice plate 53, circular openings 53a are formed at equal intervals along the X axis. In addition, circular openings 53b are formed at equal intervals along the X axis on the + Y side of the openings 53a. The openings 53a and 53b function as nozzles for ejecting ink circulating through the inkjet head 10 onto paper as a recording medium.

  In the base substrate 51, the frame 52, and the orifice plate 53 configured as described above, the frame 52 is bonded to the −Z side surface of the base substrate 51, and the orifice plate 53 is bonded to the −Z side surface of the frame 52. To be integrated.

  As can be seen with reference to FIG. 6, a flexible substrate 91 is connected to the injection unit 50. The flexible substrate 91 is a flexible substrate made of, for example, an insulating film and a conductor layer. The flexible substrate 91 is formed with an opening 91a whose longitudinal direction is the X-axis direction at the center, and slits parallel to the Y axis extending from the outer edge to the center are formed on the + Y side and the -Y side of the opening 91a. . In addition, four drive ICs 100 are mounted on the surface of the flexible substrate 91 on the + Z side.

  As shown in FIG. 7, the flexible substrate 91 is bonded to the base substrate 51 in a state where the frame 52 of the injection unit 50 is inserted into the opening 91a. The electrode pattern formed on the −Z side surface of the base substrate 51 and the conductor layer of the flexible substrate 91 are electrically connected. The driving IC 100 and the piezoelectric element constituting the injection unit 50 are connected. The electrode pattern formed on the base substrate 51 and the drive IC 100 constitute a drive circuit for driving the actuator. In the injection unit 50, the piezoelectric element of the actuator 55 is driven by the drive ICs 100A and 100B. Then, the piezoelectric element of the actuator 54 is driven by the drive ICs 100C and 100D.

  Two rigid wiring boards 92 </ b> A and 92 </ b> B are connected to the −Y side and the + Y side of the flexible board 91. Connectors and semiconductor elements are mounted on the front and back surfaces of the rigid wiring boards 92A and 92B.

  FIG. 8 is a developed perspective view of the circulation system 60. As shown in FIG. 8, the circulation system 60 includes a manifold 63, a pair of pipes 62A and 62B, and a pair of connectors 61A and 61B.

  The connectors 61A and 61B are members for connecting pipes. The connectors 61A and 61B are shaped so that the upper end and the lower end are slightly smaller. The upper ends of the connectors 61A and 61B are connected to a circulation pump that circulates ink and an ink tank that stores ink, via an ink conduit. Pipes 62A and 62B are connected to the lower ends of the connectors 61A and 61B.

  The pipes 62A and 62B are pipes whose longitudinal direction is the Z-axis direction. The pipes 62A and 62B are made of elastic rubber or fluororubber.

  The manifold 63 includes a base 63a having a flow path formed therein, and a connector 63b bonded to the base 63a.

  The connector 63b has a pair of connection portions 63c and 63d protruding in the + Z direction. The connection parts 63c and 63d are shaped so that the upper end part becomes slightly smaller.

  The base 63a connects the plurality of openings 51a formed in the base substrate 51 constituting the injection unit 50 and the connection portion 63c, and connects the plurality of openings 51b formed in the base substrate 51 and the connection portion 63d.

  In the connectors 61A and 61B, the pipes 62A and 62B, and the manifold 63 described above, the lower ends of the pipes 62A and 62B are connected to the connection portions 63c and 63d of the manifold 63, and the upper ends of the pipes 62A and 62B are connected to the connectors 61A and 61B. By being connected, they are integrated as shown in FIG. 4, and a circulation system 60 is formed.

  As shown in FIG. 8, the heat pipe 75 is an L-shaped member whose longitudinal direction is the Z-axis direction and whose lower end is bent at 90 degrees. A highly volatile working fluid is enclosed inside the heat pipe 75. The lower end portion of the heat pipe 75 is supported by the support unit 70 while being in contact with the manifold 63 of the circulation system 60.

  FIG. 9 is an exploded perspective view of the support unit 70. As shown in FIG. 9, the support unit 70 includes a support plate 71, a seal member 72, and a support member 73.

  The support plate 71 is a metal member whose longitudinal direction is the X-axis direction. At both ends 71b of the support plate 71, openings 71c penetrating in the Z-axis direction are formed. Further, two circular openings 71 a penetrating in the Z-axis direction are formed in the central portion of the support plate 71. The two openings 71a are arranged at a predetermined distance in the X-axis direction. An opening 71d is formed between the opening 71a and the opening 71c.

  The seal member 72 is a sheet-like elastic member whose longitudinal direction is the X-axis direction. The seal member 72 is made of, for example, rubber or fluororubber, and a long hole 72a whose longitudinal direction is the X-axis direction is formed at the center. In addition, circular openings 72b are formed at both ends of the seal member 72 in the X-axis direction.

  The support member 73 is a rectangular parallelepiped member whose longitudinal direction is the X-axis direction. A protrusion 73 a that protrudes upward (+ Z direction) is formed at the center of the upper surface of the support member 73. The protruding portion 73 a is shaped so as to have the same shape as the long hole formed in the seal member 72. The support member 73 is formed with two circular openings 73b penetrating downward from the upper surface of the protrusion 73a. The two openings 73b are arranged at a predetermined distance in the X-axis direction. Further, circular openings 73d penetrating from the upper surface to the lower surface are formed at both ends of the support member 73 in the X-axis direction. A notch 73 c is formed below both ends of the support member 73.

  The seal member 72 is disposed on the upper surface of the support member 73 so that the protrusion 73 a of the support member 73 described above is inserted into the elongated hole 72 a of the seal member 72. Next, the support plate 71 is fixed to the support member 73 with a bolt through the seal member 72. The support plate 71, the seal member 72, and the support member 73 are integrated to form the support unit 70. In the support unit 70, the openings 71a and 73b formed in each member coincide with each other, and the openings 71d, 72b, and 73d coincide with each other.

  Next, a procedure for assembling the case 30, the mask plate 41, the injection unit 50, the circulation system 60, the heat pipe 75, and the support unit 70 will be described.

  First, as shown in FIG. 10, a base 63 a constituting the manifold 63 of the circulation system 60 is bonded to the base substrate 51 of the injection unit 50 to which the flexible substrate 91 and the rigid wiring substrate 92 are connected. Then, with the connection portions 63c and 63d of the manifold 63 projecting from the opening 71a of the support plate 71 constituting the support unit 70, and the heat pipe 75 projecting from the opening 71d, the support member 73 of the support unit 70 is The connection portions 63c and 63d are bonded using an adhesive material having low thermal conductivity. And the heat pipe 75 and the support member 73 are adhere | attached with the adhesive agent whose heat conductivity is higher than the adhesive agent used for the connection of the connection parts 63c and 63d.

  Next, as shown in FIG. 11, the pipes 62A and 62B are connected to the connection portions 63c and 63d of the manifold 63, and the connectors 61A and 61B are connected to the pipes 62A and 62B.

  Next, the case 30 is bolted to the + Y side surface and the −Y side surface of the support member 73 constituting the support unit 70 via the seal member 95 made of rubber or fluorine rubber shown in FIG. And fix.

  As shown in FIG. 13, the two cases 30 are fixed in close contact. At this time, the connectors 61 </ b> A and 61 </ b> B are in a state of penetrating through a circular opening made of semicircular cutouts 33 and 34 provided in the case 30. And the heat pipe 75 will be in the state which penetrated the circular opening which consists of the notch 39. FIG. Further, the + X side end portion and the −X side end portion of the support unit 70 are in a state of protruding from a rectangular opening portion formed of a notch 38 provided in the case 30.

  Next, as shown in FIG. 13, flexible cables 98A and 98B are connected to connectors 921 mounted on rigid wiring boards 92A and 92B, and flexible board 91 and rigid wiring board 92A connected to flexible board 91 are connected. , 92B are accommodated in the space 30a of the case 30.

  Next, with the rigid wiring boards 92A and 92B positioned in the space 30a of the case 30, as shown in FIG. 1, the cover 40 is attached to the case 30 using bolts. Then, the mask plate 41 is covered from below with the injection unit 50 and the manifold 63, and the protrusion 41 a of the mask plate 41 is bonded to the lower surface of the base substrate 51 of the injection unit 50. The mask plate 41 is positioned by the projecting portion 41 a coming into contact with the base substrate 51 of the injection unit 50, and the upper end portion of the mask plate 41 is positioned in the notch 37 formed in the case 30.

FIG. 14 is a view showing a YZ section of the inkjet head 10 shown in FIG. When the case 30, the mask plate 41, the injection unit 50, the circulation system 60, the heat pipe 75, and the support unit 70 are assembled as described above, the cases 30 are brought into close contact with each other as shown in FIG. The circulation system 60 is accommodated in a new space composed of the space 30 a of the case 30. The flexible substrate 91 and the rigid wiring substrates 92A and 92B are accommodated in a space defined by the case 30 _{, the} cover 40, and the mask plate 41.

  In the inkjet head 10, the surface where the case 30 and the cover 40 come into contact is a flat surface. For example, an adhesive or silicon is used to seal the gap between the cover 40 and the mask plate 41 indicated by the white arrow in FIG. The space in which the flexible substrate 91 and the rigid wiring substrates 92A and 92B are accommodated is sealed, and the inkjet head 10 shown in FIG. 1 is completed.

  FIG. 15 is a perspective view showing an ink conduit 200 for supplying ink to the inkjet head 10. The ink conduit 200 is a conduit for circulating ink between an ink tank (not shown) and the inkjet head 10. The ink conduit 200 has a supply conduit 201 for supplying ink to the inkjet head 10 and a discharge conduit 202 for discharging ink from the inkjet head 10.

  The supply line 201 and the discharge line 202 that constitute the ink line 200 are made of aluminum at the point where they are connected to the inkjet head 10 and are arranged in parallel to each other. The supply pipeline 201 is provided with an L-shaped branch pipeline 201a, and the discharge pipeline 202 is provided with an L-shaped branch pipeline 202a. Further, the discharge pipe 202 is formed with heat radiation fins 202b. The inkjet head 10 and the discharge pipe 202 are not directly connected. Further, the inkjet head 10 and the discharge conduit 202 may be referred to as an inkjet head unit.

  Each branch pipeline 201a, 202a is shaped so that its lower end is slightly smaller. And the pipe 210 which consists of rubber | gum or fluororubber is connected to the lower end part of each branch pipeline 201a, 202a.

  In the inkjet head 10 shown in FIG. 1, as shown in FIG. 16, the connectors 61 </ b> A and 61 </ b> B are connected to the pipe 210, and the upper end portion of the heat pipe 75 is connected to the discharge pipe 202 by the connecting member 76. As a result, the ink line 200 is connected. In addition to the heat pipe 75, the connection member 75 may be defined as a transmission member. When the connection member 75 is included in the transmission member, the connection member 75 is also a component that constitutes the inkjet head 10.

  The connecting member 76 is a member made of, for example, aluminum or copper having a relatively high thermal conductivity. The connecting member 76 includes two parts, a base part 76a fixed to the discharge pipe line 202 and a protruding part 76b protruding from the base part 76a in the -Y direction. The heat pipe 75 is inserted into the opening provided in the protruding portion 76b and is in contact with the connecting member 76 without a gap. The base portion 76 a is fixed to the discharge conduit 202 in a state of being in close contact with the surface of the discharge conduit 202.

  FIG. 17 is a diagram illustrating the inkjet head 10 connected to the ink conduit 200 with the case 30 omitted. As shown in FIG. 17, when the inkjet head 10 is connected to the ink conduit 200, the base 63 a of the manifold 63 and the discharge conduit 202 are connected by the heat pipe 75 and the connecting member 76. Similarly, the support unit 70 and the discharge pipe line 202 are connected by the heat pipe 75 and the connection member 76. Heat transmitted from the drive IC 100 to the manifold 63 and the support unit 70 is transmitted to the discharge pipe 202 by the heat pipe 75 and the connection member 76. The heat of the discharge pipe 202 is transmitted to the ink circulating through the discharge pipe 202 and is finally radiated to the outside. Since the discharge pipe 202 is always cooled by the circulating ink, the heat generated in the inkjet head 10 is efficiently radiated.

  As described above, in the inkjet head 10 according to the present embodiment, the driving IC contacts the case 30, and the manifold 63 is connected to the discharge conduit 202 via the heat pipe 75. Heat from the driving IC and the manifold 63 can be efficiently radiated. The drive IC can be efficiently cooled. Further, since the heat dissipation efficiency with respect to the manifold 63 is improved, an increase in the temperature of the ink flowing inside the inkjet head 10 can be suppressed. Therefore, the viscosity of the ink is maintained constant, and the print quality can be improved. In particular, in the present embodiment, the heat pipe 75 is connected only to the discharge conduit 202. Therefore, the ink supplied to the inkjet head 10 is not heated, and it becomes possible to perform printing stably using the ink having a constant viscosity.

  Moreover, in the inkjet head 10 which concerns on this embodiment, the heat from the inkjet head 10 can be thermally radiated efficiently. Therefore, it is possible to improve the printing speed.

  In the inkjet head 10 according to the present embodiment, as shown in FIG. 17, the support unit 70 is connected to the discharge pipe line 202 via the heat pipe 75. Therefore, the heat transmitted from the drive IC to the support unit 70 can be efficiently radiated. The rapid thermal expansion of the support unit 70 can be suppressed, and the injection unit 50 can be positioned with high accuracy. In particular, in a printer using a plurality of inkjet heads 10, fluctuations in the positional relationship between the inkjet heads 10 can be suppressed. Therefore, it is possible to improve the print quality.

  In the inkjet head 10 according to the present embodiment, as shown in FIG. 14, the drive ICs 100 </ b> A and 100 </ b> B that control ink ejected from the openings 53 a serving as nozzles, and the control of ink ejected from the openings 53 b serving as nozzles. The driving ICs 100C and 100D that perform the above are accommodated separately. Compared to the case where four drive ICs 100A to 100D are accommodated together, the heat dissipation efficiency for one drive IC 100A to 100D is improved, and the heat generated from each drive IC 100 can be efficiently radiated.

  In the inkjet head 10 according to the present embodiment, the drive ICs 100 </ b> A to 100 </ b> D are in contact with the case 30 as illustrated in FIG. 14. Therefore, the heat generated from the drive ICs 100A to 100D can be efficiently transmitted to the case 30. By using the case 20 including the case 30 and the cover 40 as a heat sink, the heat generated from the drive ICs 100A to 100D can be efficiently radiated to the outside.

  As mentioned above, although embodiment of this invention was described, this invention is not limited by the said embodiment. For example, in the above embodiment, the case where the manifold 63 and the discharge pipe 202 are connected by the two heat pipes 75 has been described. Not limited to the above embodiment, the manifold 63 and the discharge pipe 202 may be connected by one or three or more heat pipes 75.

  In the above embodiment, the case where the manifold 63 and the discharge pipe 202 are connected by the heat pipe 75 has been described. Not limited to the above embodiment, the injection unit 50 may be connected to the discharge conduit 202 by a heat pipe 75.

  In the above embodiment, the case where the manifold 63 and the discharge pipe 202 are connected by the heat pipe 75 has been described. Not limited to the above embodiment, the manifold 63 and the discharge pipe 202 may be connected to the discharge pipe 202 by a metal material instead of the heat pipe 75. When connected to the discharge pipe 202, the efficiency is lower than that of the heat pipe 75, but the heat of the manifold 63 can be sufficiently dissipated.

  Similarly, the support unit 70 and the discharge pipe 202 may be connected to the discharge pipe 202 by a metal material instead of the heat pipe 75.

  The inkjet head 10 according to the above embodiment is an example, and the number of openings 53a and 53b provided in the ejection unit 50 and the size of the ejection unit 50 are appropriately changed according to the use and resolution of the inkjet head 10. Can do.

  Although some embodiments of the present invention have been described, the above embodiments are presented as examples and are not intended to limit the scope of the invention. The above embodiment can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. The above-described embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and equivalents thereof.

10 Inkjet Head 50 Injection Unit 54 Actuator 55 Actuator 75 Heat Pipe (Transmission Member)
201 Supply line (ink supply system)
202 Discharge pipe (ink discharge system)
100A to 100D drive IC

Claims (3)

An ejection unit having a plurality of nozzles for discharging ink that is supplied from the ink supply pipe and circulated by being discharged from the ink discharge pipe; and an actuator for discharging the ink from the nozzle;
A drive circuit for driving the actuator;
A member for connecting only to the ink discharge pipe, and a transmission member for transferring heat generated from the drive circuit to the ink discharge pipe;
An inkjet head having   The inkjet head according to claim 1, wherein the transmission member is made of metal.   The inkjet head according to claim 1, wherein the transmission member includes a heat pipe.

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