JP2006182016A - Inkjet head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet head which efficiently uses manifold component members (allows shared use of the manifold component members), and uniformizes non-uniform heat generated at a head tip 1 by a manifold. <P>SOLUTION: The inkjet head employs the manifold in which ink channel connecting ports 15, 16, 17, and grooves 18, 19 communicating with the same, are formed, and a channel spacer 40 taking up part of a space in the channel 18, is set in the channel 18. Thus a manifold main body 3 is usable in common for a head having different channels in the manifold, and by forming the channel spacer 40 of a material having good heat conductivity, the non-uniform heat generated at the head tip can be uniformized. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an inkjet head, and more particularly to a manifold structure for connecting an ink supply path to a head chip on which nozzles for ejecting ink are formed.

  An ink jet head mounted on an ink jet printer is provided with a head chip on which nozzles for ejecting ink are formed. Some head chips have a single or a plurality of nozzle rows in which a plurality of nozzles that open in the same direction form a row in one direction. The head is fixedly mounted on the carriage of the printer body. The head chip is provided with an actuator element such as a piezoelectric element that applies an ejection force to the nozzle.

As used in the inkjet head described in Patent Document 1, a manifold is used as a component for connecting an ink supply path to a head chip. As the manifold, a resin molded product or the like is preferably used.
An ink supply port communicating with the nozzle is opened on the outer surface of the head chip. The manifold has a channel connection port and a groove communicating with the channel connection port. The manifold connects the ink supply path to the head chip by applying the groove of the manifold to the ink supply port and connecting the ink supply pipe to the flow path connection port of the manifold.
Japanese Patent Laid-Open No. 2004-090494

  The flow path of the manifold needs to be designed according to ink characteristics such as ink discharge amount and ink viscosity during the recording operation. Conventionally, the entire manifold is manufactured for each flow path characteristic required for the manifold. For example, even when there is a new demand to increase or decrease the flow path cross-sectional area, a manifold with a larger or smaller flow path cross-sectional area is designed and manufactured and applied. Therefore, for example, the manifold may be redesigned every time the ink is changed, or the manifold may be redesigned to change the ink discharge amount even with the same ink.

By the way, heat generated by driving the head chip may affect the ejection characteristics of the nozzle. When heat is unevenly distributed in the head chip, the ejection characteristics differ depending on the position of the nozzle, which affects the performance. The unevenly distributed heat of the head chip is diffused through the ink filled in the manifold and is made uniform.
However, as the manifold cross-sectional area is reduced, the problem of heat non-uniformity generated in the head chip becomes more serious, and the output characteristics of the nozzles in the head vary due to the temperature distribution of the ink.

Accordingly, an object of the present invention is to make the use of manifold parts more efficient in the inkjet head by using a manifold structure that connects an ink supply path to a head chip on which nozzles are formed.
It is another object of the present invention to suppress a decrease in thermal conductivity associated with a reduction in the flow path cross-sectional area of the manifold, and to promote the uniformity of non-uniform heat generated in the head chip.

The invention according to claim 1 for solving the above-described problems includes a head chip in which a nozzle for ejecting ink and an ink supply port communicating with the nozzle are formed;
An ink channel connection port and a manifold formed with a groove communicating with the ink channel connection port;
The surface of the head chip on which the ink supply port is formed is combined with the surface of the manifold on which the groove is formed to form an ink flow path, and the nozzle from the ink flow path connection port via the ink flow path In an ink jet head that connects the ink flow path up to
A spacer that occupies a part of the space in the groove is installed in the groove to form an ink flow path, and the ink flow path from the ink flow path connection port to the nozzle can flow through the ink flow path. It is an inkjet head characterized by being connected to.

  The invention according to claim 2 is the ink jet head according to claim 1, wherein the spacer is held at a fixed position in the groove.

  The invention according to claim 3 is the ink jet head according to claim 1, wherein the spacer is integrally formed along the shape of the groove.

  According to a fourth aspect of the present invention, the spacer includes a bottom portion that fits in a bottom of the groove, and an edge wall portion that is erected on an edge of the bottom portion and holds a gap between the head chip and the bottom portion. 2. The ink jet head according to claim 1, wherein the ink jet head is an ink jet head.

  The invention according to claim 5 is the ink jet head according to claim 1, wherein the spacer is composed of two or more parts.

  The invention according to claim 6 is the ink jet head according to claim 1, wherein the spacer has a layer structure of two or more layers.

  According to the seventh aspect of the present invention, as δ1 / δ2> 1, all of the spacers or the portion forming the inner surface of the ink flow path is made of a material having thermal conductivity δ1, and all of the manifold or the groove is formed. The inkjet head according to claim 1, wherein the portion to be formed is made of a material having a thermal conductivity δ2.

  According to an eighth aspect of the present invention, as δ1 / δ2> 20, all of the spacers or a portion forming the inner surface of the ink flow path is made of a material having a thermal conductivity δ1, and all of the manifold or the groove is formed. The inkjet head according to claim 1, wherein the portion to be formed is made of a material having a thermal conductivity δ2.

  According to the ninth aspect of the present invention, δ1 / δ3> 1 is satisfied, and the part of the spacer or the portion forming the inner surface of the ink flow path is made of a material having a thermal conductivity of δ1, and the thermal conductivity of the applied ink is δ3. The inkjet head according to claim 1, wherein:

  In the tenth aspect of the present invention, δ1 / δ3> 20 is satisfied, and the entire part of the spacer or the portion forming the inner surface of the ink flow path is made of a material having thermal conductivity δ1, and the thermal conductivity of the applied ink is δ3. The inkjet head according to claim 1, wherein:

  According to the present invention, the ink flow path connected to the head chip can be formed by the manifold, and the spacer occupying a part of the space in the groove is installed in the groove of the manifold. By selecting whether to install or not, and selecting the shape and size of the spacer to be installed, different flow paths can be configured in the manifold. The manifold main body, which is a manifold component other than the spacer, can be shared among the manifolds having different flow paths, and the use of the manifold component becomes efficient.

  According to the invention described in claim 2, since the spacer is held at a fixed position in the groove of the manifold, the flow path by the manifold is formed uniformly.

  According to the third aspect of the present invention, since the spacer is integrally formed along the shape of the groove of the manifold, the spacer can be easily installed.

  According to the fourth aspect of the present invention, the spacer has a bottom portion that fits in the bottom of the groove of the manifold, and an edge wall portion that stands on the edge of the bottom portion and holds the gap between the head chip and the bottom portion. Can be fixed in the groove of the manifold and aligned with the head chip, the spacer can be fixed without using an adhesive or the like, and a constant ink flow path can be formed.

  According to the invention described in claim 5, since the spacer is composed of two or more parts, it is possible to promote the selection of the right material at the right place, the selection of the manufacturing method suitable for each part, and the commonality of the parts. it can.

  According to the invention described in claim 6, since the spacer has a layer structure of two or more layers, selection of an appropriate material at an appropriate place and selection of a manufacturing method suitable for each layer can be promoted.

  According to the seventh aspect of the present invention, since the thermal conductivity of at least the portion of the spacer that forms the ink flow path is larger than that of the whole manifold or the portion that forms the groove of the manifold, the flow of the manifold can be reduced by installing the spacer. Even if the road cross-sectional area is reduced, the decrease in thermal conductivity is alleviated, and the local heat generated in the head chip is more efficiently conducted and uniformed by the spacer than the member forming the manifold groove.

  According to the eighth aspect of the present invention, since the thermal conductivity of at least the portion of the spacer that forms the ink flow path is larger than 20 times the thermal conductivity of the entire manifold or the portion that forms the groove of the manifold, The thermal conductivity in the ink flow path can be remarkably improved at low cost by using a general-purpose material such as installing a metal spacer with respect to the manufactured manifold.

  According to the ninth aspect of the present invention, since the thermal conductivity of at least the portion of the spacer that forms the ink flow path is larger than the applied ink, even if the flow path cross-sectional area of the manifold is reduced by installing the spacer, The thermal conductivity is improved, and the local heat generated in the head chip is efficiently conducted and uniformed.

  According to the tenth aspect of the present invention, since the thermal conductivity of at least the portion of the spacer that forms the ink flow path is larger than 20 times the thermal conductivity of the applied ink, it is made of metal compared to general ink. The thermal conductivity in the ink flow path can be remarkably improved at low cost by using a general-purpose material such as installing a spacer.

  An embodiment of the present invention will be described below with reference to the drawings. The following is one embodiment of the present invention and does not limit the present invention. FIG. 1 is an overall perspective view of the ink jet head of this embodiment. 2 and 3 are exploded and partial perspective views, FIG. 4 is a cut and exploded perspective view, and FIG. 5 is a cut and partial perspective view (without spacers). FIG. 6 shows a single perspective view of the manifold (with spacers). XYZ axes common to all drawings are displayed on the drawing.

The ink jet head according to the present embodiment includes a head chip 1, a frame 2, a manifold body 3, a cap receiving plate 4, a circuit board 5, a connector 6, and a flexible wiring board 7.
A connector 6, a drive circuit (not shown) and the like are mounted on the circuit board 5. One end of the flexible wiring board 7 is connected to the circuit board 5, and the other end is connected to the column electrode exposed on the surface of the head chip 1. The head chip 1 is configured with nozzle rows arranged in the X direction. Each nozzle is provided with an actuator element such as a piezoelectric element. The actuator element is connected to the column electrode.
In accordance with the signal input from the connector 6, the drive circuit on the circuit board 5 generates a drive voltage, applies the drive voltage to the actuator element via the flexible wiring board 7 and the column electrode, and pressurizes the ink chamber in front of the nozzle. Dispense power to the nozzle.

An ink supply port 13 communicating with the nozzles is opened on the surface of the head chip 1. On the inner side of the manifold body 3 facing the head chip 1, a groove serving as an ink flow path is formed as shown in FIG.
As shown in FIGS. 3, 4, and 6, a flow path spacer 40 is installed in the U-shaped groove 18 of the manifold body 3. As shown in FIG. 5, the filter 14 is mounted on the U-shaped groove 18 of the manifold body 3. The filter 14 is welded by melting the rib provided on the edge of the groove 18.
The flow path spacer 40 occupies a part of the space in the groove 18 and reduces the cross-sectional area of the flow path by the groove 18. The flow path spacer 40 is integrally formed in a U-shape along the shape of the groove 18, and can be inserted and removed from the upper end opening of the groove 18 during assembly.
The channel spacer 40 includes a bottom portion 40a and an edge wall portion 40b. The bottom portion 40 a has a shape and size that fits into the bottom of the groove 18. An edge wall portion 40b is erected on the edge of the bottom portion 40a. The bottom 40 a is thinner than the depth of the groove 18. When the flow path spacer 40 is installed in the groove 18, the top of the edge wall portion 40 b has a height up to the surface of the groove 18 where the filter 14 is installed.
With this structure, when the filter 14 is attached, the flow path spacer 40 is held at a fixed position in the groove 18. The edge wall portion 40b is locked to the filter 14 and holds the gap between the head chip 1 and the bottom portion 40a.
When the flow path spacer 40 is installed, the flow path spacer 40 forms a U-shaped groove 41 that is slightly smaller than the inside of the U-shaped groove 18, and the flow path is formed by the groove 41. When the flow path spacer 40 is not installed, the flow path is formed by the groove 18.

  The manifold body 3 covers the surface of the head chip 1, covers the ink supply port 13 of the head chip 1, and connects the ink flow path formed by its own groove to the ink supply port 13 of the head chip 1.

  On both sides of the chip mounting surface of the frame 2, flow path connection parts 8 and 9 are attached. The pipes 10 and 11 are connected to the upper surface of the flow path connection component 8, and the side connection ports 15 and 16 of the manifold body 3 are connected to the inner surface of the flow path connection component 8. A pipe 12 is connected to the upper surface of the flow path connection component 9, and a side connection port 17 of the manifold body 3 is connected to the inner surface of the flow path connection component 9.

Ink is supplied from the tube 10. The pipe 10 communicates with the side connection port 15 of the manifold main body 3 through the flow path connection component 8, and then the groove 18, the side connection port 16, and the pipe 11, and passes through the filter 14 in the manifold main body 3. The previous ink is distributed. As shown in FIG. 5, the ink that has passed through the filter 14 in the groove 18 is given to the ink supply port 13 through a flow path 20 formed by a gap between the filter 14 and the head chip 1. The flow path 20 communicates with the pipe 12 via the groove 19 and the side connection port 17 shown in FIGS. 3 and 6 and the flow path connection component 9 shown in FIG. The ink can be discharged.
The ink supplied from the ink supply port 13 to the head chip 1 is ejected from the nozzle by driving the actuator element described above.

The cap receiving plate 4 is disposed with the lower end portion of the head chip 1 housed in an opening formed in the center thereof.
One purpose of the cap receiving plate 4 is to bring the cap into close contact. This cap is in close contact with the cap receiving plate 4 around the head chip 1 so as to cover the lower end surface where the nozzle outlet of the head chip 1 opens. In some cases, a suction device is connected to the cap, and the suction device sucks ink or the like from the nozzle of the head chip 1 through a cap that is in close contact with the cap receiving plate 4.

The frame 2 is preferably made of a plate material such as a metal plate and has a good plate thickness accuracy. The frame 2 is provided with a mounting hole.
The head chip 1 is mounted on the surface of the frame 2. The head chip 1 is mounted on the frame 2 with the back surface of the head chip 1 aligned with the surface of the frame 2 and the lower end of the head chip 1 protruding from the lower end of the frame 2.

After assembling the above structure, resin is attached to the periphery of the manifold body 3 and cured, so that each component is fixed to the frame 2 and a gap is not generated in the flow path.
When the inkjet head is mounted on the printer main body, the back surface of the frame 2 is supported by the surface of a member provided on the main body side, and is fixed with a bolt or the like using a hole formed in the frame 2.

By selecting whether or not to install the flow path spacer as described above, different flow paths can be configured in the manifold.
For example, as shown in FIG. 7, different flow paths can be formed in the manifold by selecting the shape and size of the spacers to be installed.
FIG. 7 is a cross-sectional view of flow path spacers having different thicknesses. The flow path spacer 42 shown in FIG. 7A includes a bottom part 42a and an edge wall part 42b. The flow path spacer 43 shown in FIG. 7B includes a bottom 43a and an edge wall 43b. One bottom part 42a is formed thicker than the other bottom part 43a. The height from the bottom surface of the bottom portion 42a to the upper end of the edge wall portion 42b in one flow path spacer 42 is the same as the height from the bottom surface of the bottom portion 43a to the upper end of the edge wall portion 43b in the other flow channel spacer 43. D. This dimension D is made to coincide with the height from the bottom of the groove 18 of the manifold body 3 to the surface on which the filter 14 is installed (same in FIGS. 8 and 9). The other dimensions of both flow path spacers 42 and 43 are matched with the groove 18 of the manifold body 3.
By producing a plurality of such channel spacers having different bottom thicknesses and selecting them, channels having different depths can be easily and quickly configured in the manifold.
In addition, by producing a plurality of flow path spacers having different thicknesses of the edge wall portions and selecting them, flow paths having different widths can be configured in the manifold easily and quickly.
In addition, by preparing flow path spacers of various shapes and selecting them, a wide variety of flow paths can be configured in the manifold easily and quickly.

It is also effective to configure the flow path spacer from two or more parts. For example, as shown in FIG. 8A, a flow path spacer 45 having a bottom portion and an edge wall portion and having an outer shape that fits into and fits into the groove 18 of the manifold body 3 is produced. On the other hand, as shown in FIG. 8 (b), a flow path spacer 46, which is also composed of a bottom portion and an edge wall portion and fits inside the flow path spacer 45 and has an outer shape that fits, is produced. Dimensions D and E are taken as shown.
By installing the flow path spacer 45 in the groove 18 of the manifold body 3, a flow path having a smaller cross-sectional area than the groove 18 of the manifold body 3 can be formed.
Furthermore, as shown in FIG. 8 (c), by installing and using a flow path spacer 46 in the flow path spacer 45, a flow path with a smaller cross-sectional area can be formed.
In addition, the flow path spacer may be composed of two or more parts by various configurations. However, as shown in FIG. 8D, the flow path spacer is divided into an upper portion that contacts ink and a lower portion that does not contact ink. One effective method is to make up two or more parts. It is possible to select a material and a manufacturing method in consideration of contact with ink. FIG. 8D shows a flow path spacer in which a plate-like spacer 47 and a spacer 48 having a bottom portion and an edge wall portion are combined.
It is also effective to form the spacer with a layer structure of two or more layers. For example, as shown in FIG. 9, there can be mentioned a flow path spacer 49 in which a coating layer 49b such as a metal film is attached to the surface of a base material 49a having a bottom part and an edge wall part.

  For the purpose of changing the design of the flow path, the same material is sufficient for the manifold body 3, the flow path spacers 40, 42, 43, 45, 46, 47, 48, and the base material 49a. Apply. For the purpose of improving thermal conductivity, a material having good thermal conductivity such as metal is applied as the material of the channel spacers 40, 42, 43, 45, 46, 47, 48 and the base material 49a. 8 (c), the flow path spacer 45 and the flow path spacer 46 are made of a material having low thermal conductivity such as resin, and the flow path spacer 46 is made of metal or the like. It is good also as a material with high heat conductivity of these, and it is good also as both materials with high heat conductivity, such as a metal. In the two-part flow path spacer shown in FIG. 8 (d), the spacer 47 may be made of a material with low thermal conductivity such as resin, and the spacer 48 may be made of a material with high thermal conductivity such as metal. A material having high thermal conductivity such as metal may be used. In the channel spacer 49 shown in FIG. 9, the base material 49a may be made of a material having low thermal conductivity such as resin, and the coating layer 49b may be made of a material having high thermal conductivity such as metal. It may be a highly conductive material.

Here, the thermal conductivity of each part of the spacer or the part forming the inner surface of the ink flow path is δ1, the thermal conductivity of each part of the manifold or the part forming the groove for the flow path is δ2, and the thermal conductivity of the applied ink. Let the rate be δ3. In the case of the two-part spacer shown in FIGS. 8C and 8D, the thermal conductivity of each part of the spacer or the flow path spacers 46 and 48 is applied to δ1. In the case of the flow path spacer 49, each constituent material of the spacer or the coating layer 49 is applied to δ1. In the case of the manifold, when the part forming the channel groove is made of a material different from that of the other part, only the thermal conductivity of the part may be applied as δ2, or the thermal conductivity of each constituent material may be set to δ2. You may apply.
For the purpose of improving the thermal conductivity in the ink flow path formed by the manifold, δ1 / δ2> 1, δ1 / δ3> 1, preferably δ1 / δ2> 20, δ1 / δ3> 20.
The material is selected so that
For example, for a resin-made manifold body having a thermal conductivity of 0.1 to 0.5 [W / m · K], aluminum (thermal conductivity) 238 [W / m · K]), stainless steel (thermal conductivity 16 [W / m · K]), alumina (thermal conductivity 21 [W / m · K]), or the like is applied. The thermal conductivity of the applied ink is, for example, about 0.4 [W / m · K].

  Other examples of materials exhibiting high thermal conductivity that can be used include silver, copper, nickel, iron, gold, platinum, tin lead, and magnesium, but the present invention is not limited thereto.

Using an inkjet head having a head driving frequency of 10 kHz and a head channel number of 128 channels, the temperature difference between the inks at both ends during continuous driving of only the 64 channels on the rear side of the driving head flow path was measured. The ink used was a water-based ink having a viscosity of 4 cp. The power consumption is about 0.3 W / 64 channels. Using the same manifold made of PPS (30% glass fiber), (1) When using only the manifold (no spacer), (2) When using the same material spacer for the manifold, (3) (2) In the case where an aluminum spacer having the same shape as that of the spacer used in the above was used, the temperature difference between the inks at both ends was measured by driving under the above conditions. Table 1 summarizes the results.

As shown in Table 1, the temperature difference is reduced at both ends.
In general accuracy (± 10%), this is an allowable range, but when high-precision (± 1%) driving is required, this number is a value that cannot be ignored.

1 is an overall perspective view (front side) of an inkjet head according to an embodiment of the present invention. 1 is an exploded and partial perspective view of an inkjet head according to an embodiment of the present invention. 1 is an exploded and partial perspective view of an inkjet head according to an embodiment of the present invention. 1 is a cut / disassembled / partial perspective view of an inkjet head according to an embodiment of the present invention. 1 is a cut / partial perspective view (without a spacer) of an inkjet head according to an embodiment of the present invention. It is the independent perspective view (with a spacer) of the manifold of one Embodiment of this invention. It is sectional drawing of the flow-path spacer of one Embodiment of this invention. It is sectional drawing of the flow-path spacer of one Embodiment of this invention. It is sectional drawing of the flow-path spacer of one Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Head chip 2 Frame 3 Manifold body 4 Cap receiving plate 5 Circuit board 6 Connector 7 Flexible wiring boards 8 and 9 Flow path connection component 13 Ink supply port 14 Filter 40 Flow path spacer

Claims (10)

A head chip formed with a nozzle for ejecting ink and an ink supply port communicating with the nozzle;
An ink channel connection port and a manifold formed with a groove communicating with the ink channel connection port;
The surface of the head chip on which the ink supply port is formed is combined with the surface of the manifold on which the groove is formed to form an ink flow path, and the nozzle from the ink flow path connection port via the ink flow path In an ink jet head that connects the ink flow path up to
A spacer that occupies a part of the space in the groove is installed in the groove to form an ink flow path, and the ink flow path from the ink flow path connection port to the nozzle can flow through the ink flow path. An ink jet head connected to the ink jet head.   The inkjet head according to claim 1, wherein the spacer is held at a fixed position in the groove.   The inkjet head according to claim 1, wherein the spacer is integrally formed along the shape of the groove.   The said spacer has the bottom part fitted in the bottom of the said groove | channel, and the edge wall part standingly arranged at the edge of the said bottom part, and hold | maintaining the gap of the said head chip and the said bottom part, The Claim 1 characterized by the above-mentioned. Inkjet head.   The inkjet head according to claim 1, wherein the spacer is composed of two or more parts.   The inkjet head according to claim 1, wherein the spacer has a layer structure of two or more layers.   As δ1 / δ2> 1, all of the spacers or the portion forming the inner surface of the ink flow path is made of a material having a thermal conductivity δ1, and all of the manifold or the portion forming the groove is a material having a thermal conductivity δ2. The inkjet head according to claim 1, comprising:   As δ1 / δ2> 20, all of the spacers or a portion forming the inner surface of the ink flow path is made of a material having a thermal conductivity δ1, and all of the manifold or a portion forming the groove is a material having a thermal conductivity δ2. The inkjet head according to claim 1, comprising:   The structure of δ1 / δ3> 1, wherein all of the spacers or the portion forming the inner surface of the ink flow path is made of a material having a thermal conductivity δ1, and the thermal conductivity of the applied ink is δ3. 2. An ink jet head according to 1.   The structure of δ1 / δ3> 20 is satisfied, wherein all of the spacers or a portion forming the inner surface of the ink flow path is made of a material having a thermal conductivity δ1, and the thermal conductivity of the applied ink is δ3. 2. An ink jet head according to 1.

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