JP4682605B2 - Inkjet head and inkjet printer - Google Patents

Description

  The present invention relates to an ink jet head and an ink jet printer, and more particularly to a head chip positioning structure in 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.
When the inkjet head is mounted on the printer main body, the positional accuracy of the nozzle is important. In a head chip having a nozzle row, it is necessary to determine the nozzle row direction and the relative position along the nozzle row direction in addition to the nozzle shaft direction and the relative position along the nozzle axis direction.
Among these, when the nozzle row direction changes, the nozzle row direction with respect to the main scanning direction changes, so the pitch of dots formed on the printing medium changes and affects the printing quality. Also, in a printer equipped with a head corresponding to each color in multicolor printing, if the nozzle row angle between the heads is different, the dot pitch will be different and affect the recording quality. High is desired.

In the inkjet head described in Patent Document 1, the head chip is held at a predetermined position with respect to the housing frame by fitting both upper corners of the head chip to the head chip holding part. Further, the lower end portion of the head chip is sandwiched between two manifolds, and a cap receiving plate is attached to the lower ends of the two manifolds to assemble them, and the position of the head chip with respect to the housing frame is fixed. The height position is determined by seating the bottom surface of the housing frame on the seating surface of the carriage. In the direction parallel to the seating surface, a mechanism for fine adjustment is configured, whereby the nozzle row direction is finally adjusted.
The ink jet head described in Patent Document 1 has a configuration in which ink supply ports and electrodes are formed on both surfaces of a head chip, and ink is supplied from the ink supply ports on both surfaces with the manifold aligned with both surfaces of the head chip. This is a configuration in which flexible wiring is connected.
Japanese Patent Laid-Open No. 2004-090494

It is desired to have a head configuration in which the influence of the forming accuracy and assembly accuracy of each component constituting the head is minimized with respect to the nozzle position accuracy.
In addition, there has been no conventional head configuration that emphasizes the accuracy in the nozzle row direction.

  Accordingly, the present invention reduces the influence of component forming accuracy and assembly accuracy on nozzle position accuracy, particularly nozzle row direction accuracy, and determines nozzle position, particularly nozzle row direction, with high accuracy. It is an object of the present invention to provide an ink jet head and an ink jet printer capable of performing the above.

The invention according to claim 1 for solving the above-described problem is that a plurality of nozzles are opened in a row in one direction, a lower end surface that is continuous at a right angle to the lower end surface, and parallel to the row direction of the nozzles. A reverse surface, an ink supply port communicating with the nozzle opposite to the reverse surface, a surface on which an electrode for applying a voltage for applying ejection force to the nozzle is exposed, and the lower end surface, the reverse surface, and the surface. A rectangular parallelepiped head chip composed of both continuous side surfaces and an upper end surface opposed to the lower end surface, with the front and back surfaces being the largest surface,
A frame having a surface having a chip mounting surface in contact with the lower surface of the head chip at a position contacting the lower end, and a back surface having a plane parallel to the chip mounting surface;
A manifold that covers the surface of the head chip and has a flow path that connects to the ink supply port;
The chip and the first position regulating structure of the movement restricting each other for each bi-directional parallel two orthogonal axes on the chip mounting surface and the said head chip manifold at a predetermined position, and the said frame manifold at a predetermined position have a second position regulating structure of the movement restricting each other for each one-way parallel two orthogonal axes on the mounting surface,
In the inkjet head, the head chip, the frame, and the manifold are positioned and fixed to each other by the first and second position restricting structures .

  In addition, although the surface where the discharge port of the nozzle opens is referred to as a “lower end surface”, there is no significance in specifying the mounting direction of the inkjet head. Also, the side on which the head chip of the frame is mounted is merely the front side, and the words “front surface” and “back surface” have no further significance.

According to a second aspect of the present invention, in the first position restriction structure, the position restriction that restricts movement of the head chip and the manifold in both directions of one axis parallel to the chip mounting surface and perpendicular to the nozzle row. 2. The ink jet head according to claim 1, wherein the structure includes a groove formed on a surface of the head chip and a convex portion formed on the manifold fitted into the groove.

According to a third aspect of the present invention, in the first position restricting structure, the position restricting structure that restricts movement of the head chip and the manifold in both directions of one axis parallel to the nozzle row is provided on the head chip. The inkjet head according to claim 1 or 2, comprising both side walls formed in the manifold sandwiching both side surfaces.

According to a fourth aspect of the present invention, in the second position restricting structure, the frame and the manifold are position-regulated for restricting movement of one frame in one direction parallel to the chip mounting surface and perpendicular to the nozzle row. 4. The ink jet head according to claim 1, wherein the structure includes a protrusion formed on the manifold that engages with a lower end of the frame.

According to a fifth aspect of the present invention, in the second position restricting structure, the position restricting structure that restricts movement of the frame and the manifold with respect to one direction of one axis parallel to the nozzle row is provided at a lower end of the frame. 4. The ink jet head according to claim 1, wherein the ink jet head comprises: a step formed on the manifold; and a protrusion formed on the manifold engaged with the step.

  According to a sixth aspect of the present invention, there is provided a plate member having an opening, the lower end of the head chip being disposed in the opening, and the lower end surface of the head chip being exposed from the opening, and standing from an edge of the plate member. It has a structure in which the three members are clamped by pressing the frame, the manifold, and the head chip disposed between them together in a direction perpendicular to the chip mounting surface by an elastic claw provided. The inkjet head according to any one of claims 1 to 4.

A seventh aspect of the present invention is an ink jet printer including the ink jet head according to any one of the first to sixth aspects, wherein a plane parallel to the chip mounting surface on the back surface of the frame is a surface. It is an inkjet printer formed by supporting and fixing.

According to the present invention, the back surface of the head chip is mounted in contact with the chip mounting surface of the frame with the back surface of the head chip being perpendicular to the chip lower end surface where the nozzle opens and parallel to the row direction of the nozzle. The back surface of the frame is provided with a plane parallel to the chip mounting surface.
Therefore, by fixing the plane parallel to the chip mounting surface on the back side of the frame to the mounting surface on the printer body side, this mounting surface and the nozzle row are accurately parallel, so the direction of the nozzle row can be accurately indicated. Can do.
The back surface of the head chip is one of the largest surfaces of the head chip, and since it is in contact with the chip chip mounting surface of the frame and stably supported, there is almost no assembly error due to backlash between parts. can do. At the same time, there is no accumulation of assembly errors due to the intervention of other parts other than the frame. As a result, the accuracy of the nozzle row direction is improved.

  Since the ink supply port and the electrode exposed portion are formed on the surface of the head chip, the manifold and the wiring do not get in the way when the back surface of the head chip is aligned with the chip mounting surface of the frame.

Just by aligning the back surface of the head chip with the chip mounting surface, the position of the head chip with respect to two orthogonal axes parallel to the chip mounting surface cannot be determined. The present invention positions the head chip with respect to the frame about two orthogonal axes parallel to the chip mounting surface through a manifold.
That is, according to the present invention, the first position restricting structure for restricting movement of the head chip and the manifold with respect to both directions of two orthogonal axes parallel to the chip mounting surface at a predetermined position, and the frame and the manifold with the chip mounted at the predetermined position. A second position restricting structure that restricts movement in each direction of two orthogonal axes parallel to the surface is provided.
Therefore, if the manifold is urged in each direction locked to the frame, the position of the manifold with respect to the frame is determined. Furthermore, since the head chip and the manifold are locked with each other in both directions of two orthogonal axes parallel to the chip mounting surface, the position of the head chip with respect to the frame is determined via the manifold.
The head chip, the frame, and the manifold are positioned and fixed to each other by the first and second position restricting structures.
As described above, the position of the nozzle provided in the head chip is determined with high accuracy.

  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. 1 and 2 are overall perspective views of the ink jet head of this embodiment. 3 is an exploded and partial perspective view, FIG. 4 is a partial perspective view, FIG. 5 is a cut and partial perspective view, and FIG. 6 is an exploded and partial perspective view. The XYZ axes common to all the drawings are displayed on the drawing.

As shown in FIGS. 1 and 2, the inkjet head of this embodiment includes a head chip 1, a frame 2, a manifold 3, a cap receiving plate 4, a circuit board 5, a connector 6, and a flexible wiring board 7. Is provided.
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 3 facing the head chip 1, a groove serving as an ink flow path is formed as shown in FIG. As shown in FIG. 5, the filter 14 is mounted on the U-shaped groove 18 of the manifold 3. The filter 14 is welded by melting the rib provided on the edge of the groove 18. The manifold 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. Pipes 10 and 11 are connected to the upper surface of the flow path connection component 8, and side connection ports 15 and 16 (shown in FIG. 6) of the manifold 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 (shown in FIG. 6) of the manifold 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 3 through the flow path connection component 8, followed by the groove 18, the side connection port 16, and the pipe 11, before passing through the filter 14 in the manifold 3. 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. Further, the flow path 20 communicates with the pipe 12 via the groove 19 and the side connection port 17 shown in FIG. 6 and the flow path connection component 9 shown in FIG. 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 4a formed at 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.
As shown in FIGS. 3 to 5, 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.

A groove 21 is cut in the X direction on the surface of the head chip 1. The groove 22 is fitted with a convex portion 22 formed in the edge of the manifold 3 in the X direction. This restricts movement of the head chip 1 and the manifold 3 in both directions of the Y axis.

Side walls 23 and 24 formed at both ends of the manifold 3 in the X direction protrude from the mating surfaces of the head chip 1 and the manifold 3. The dimension between the side walls 23 and 24 is slightly larger than the dimension of the head chip 1 in the X direction. The side walls 23 and 24 sandwich the both side surfaces of the head chip 1, thereby restricting the movement of the head chip 1 and the manifold 3 in both directions of the X axis.

Following the protruding ends of the side walls 23 and 24 of the manifold 3, protrusions 25 and 26 are formed to protrude in the positive direction of the Z axis.
When the manifold 3 is urged with respect to the frame 2 in the positive direction of the Y axis, the projections 25 and 26 engage with the lower end surface 27 of the frame 2, that is, the upper surfaces of the projections 25 and 26 are the lower end surface 27 of the frame 2. To touch. Thereby, the movement of the frame 2 and the manifold 3 is restricted with respect to one direction of the Y axis. Considering the frame 2 as a reference, the movement of the manifold 3 is restricted in the positive direction of the Y axis.

A step of about 0.5 mm is formed at the lower end of the frame 2. The protrusion 25 is engaged with the step in such a manner that the inner surface of the protrusion 25 is brought into contact with the vertical surface 28 generated by the step. Thereby, the movement of the frame 2 and the manifold 3 is restricted with respect to one direction of the X axis. Considering the frame 2 as a reference, the movement of the manifold 3 is restricted in the positive direction of the X axis.

In order to restrict the movement of the frame 2 and the manifold 3 with respect to one direction of the X axis, the step at the lower end of the frame 2 is sufficient on only one side, but in this embodiment, as shown in FIG. Has a step.
As shown in FIG. 7, lower end surfaces 27 that contact the upper surfaces of the protrusions 25 and 26 of the manifold 3 are formed at the same height on both sides of the step. As a result, the horizontality (angle around the Z axis) of the manifold 3, and consequently the head chip 1, is stabilized.
As the side surfaces of the portion 29 protruding to a position lower than the lower end surface 27, the above-described vertical surfaces 28 are formed on both sides. By urging the manifold 3 in the positive direction of the X-axis, the inner surface of the protrusion 25 comes into contact with the vertical surface 28 and the movement of the manifold 3 with respect to the frame 2 is restricted. On the other hand, by urging the manifold 3 in the negative direction of the X axis, the inner surface of the protrusion 26 contacts the vertical surface 28 and the movement of the manifold 3 with respect to the frame 2 is restricted.

After assembling the above structure, resin is attached to the periphery of the manifold 3 and cured, thereby fixing each component to the frame 2 and preventing a gap from being 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.

In order to temporarily fix the head chip 1, the manifold 3, and the cap receiving plate to the frame 2 at the time of assembly, it is preferable to use a cap receiving plate 30 having elastic claws 31a to 31e as shown in FIG. The elastic claws 31a to 31e are erected by bending from both edges along the longitudinal direction of the cap receiving plate. The cap receiving plate 30 is formed by press forming from a metal plate material having elasticity.
As shown in FIGS. 9 and 10, the elastic claws 31 a to 31 e press the frame 2, the manifold 3, and the head chip 1 disposed between the two in the Z direction to press these three members 1, 2, 3. Hold it. After temporarily fixing the head chip 1, the manifold 3 and the cap receiving plate 30 to the frame 2 with the cap receiving plate 30 having the elastic claws 31a to 31e, the resin is adhered to the periphery of the manifold 3 as described above. Harden and fix.

According to the above structure, the direction of the nozzle row formed on the head chip 1 is accurately adjusted in a direction parallel to the back surface of the frame 2 by mounting the head chip 1 on the plate-like frame 2 in surface contact. Determined. By increasing the plate thickness accuracy of the frame 2, the accuracy in the direction of the nozzle row of the head chip 1 can be increased.
As described above, the head chip 1 (including nozzles) is positioned through the manifold 3 in the direction parallel to the chip mounting surface. Therefore, it is affected by the formation error of the head chip 1, the frame 2, and the manifold 3 including the vertical surface 28 due to the groove 21, the convex portion 22, the side walls 23 and 24, the protrusions 25 and 26, and the steps.
However, the positional accuracy of the nozzles in the direction perpendicular to the chip mounting surface can be increased by increasing the thickness accuracy of the frame 2 and the formation accuracy of the head chip 1, and the surface of the frame 2 and the back surface of the head chip 1 are improved. Since they are in contact with each other and no other parts such as the manifold 3 are interposed, the influence of assembly errors is very small.

In the above embodiment, the frame 2 has a plate shape, and the entire front surface and the entire back surface are each formed as a single plane. However, a protrusion or the like may be provided around the chip mounting surface of the frame 2. Only the part of the back surface of the frame 2 that is aligned with the printer main body may be a plane parallel to the chip mounting surface, and a convex part or the like may be provided on the other part. It is only necessary to secure a chip mounting surface on the surface of the frame 2, that is, a surface with which the back surface of the head chip 1 contacts, and a surface parallel to the surface to be formed on the back surface of the frame 2.
When the entire back surface of the frame 2 is configured as a single plane as in the above embodiment, the ink jet head is well placed, and the level and stability with respect to the support surface are improved. When the frame 2 is plate-shaped and the entire front surface and the entire back surface are each configured as a single plane, it is easy to form and the plate thickness accuracy is easily obtained.

1 is an overall perspective view (front side) of an inkjet head according to an embodiment of the present invention. 1 is an overall perspective view (back 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 a partial perspective view of an inkjet head according to an embodiment of the present invention. 1 is a cut / 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. It is sectional drawing which shows the positional relationship in the frame lower end part which concerns on one Embodiment of this invention. 1 is a perspective view of a cap receiving plate having elastic claws according to an embodiment of the present invention. It is a whole perspective view (front side) of an ink-jet head at the time of using a cap backing plate with an elastic claw. It is a whole perspective view (back side) of an ink jet head at the time of using a cap backing plate with an elastic claw.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Head chip 2 Frame 3 Manifold 4 Cap receiving plate 5 Circuit board 6 Connector 7 Flexible wiring board 8, 9 Flow path connection component 13 Ink supply port 14 Filter 31a-31e Elastic nail

Claims (7)

A plurality of nozzles opening in a row in one direction, a back surface that is perpendicular to the bottom surface, parallel to the nozzle row direction, and opposed to the back surface and communicating with the nozzles A surface on which an electrode for applying a voltage for applying a discharge force to the nozzle is exposed; a bottom surface, a back surface and both side surfaces continuous to the surface; and an upper surface facing the lower surface; A rectangular parallelepiped head chip having the largest surface on the front and back surfaces, and
A frame having a surface having a chip mounting surface in contact with the lower surface of the head chip at a position contacting the lower end, and a back surface having a plane parallel to the chip mounting surface;
A manifold that covers the surface of the head chip and has a flow path that connects to the ink supply port;
The chip and the first position regulating structure of the movement restricting each other for each bi-directional parallel two orthogonal axes on the chip mounting surface and the said head chip manifold at a predetermined position, and the said frame manifold at a predetermined position have a second position regulating structure of the movement restricting each other for each one-way parallel two orthogonal axes on the mounting surface,
An ink-jet head , wherein the head chip, the frame, and the manifold are positioned and fixed to each other by the first and second position restricting structures . Of the first position restriction structure, a position restriction structure that restricts movement of the head chip and the manifold in both directions of one axis parallel to the chip mounting surface and perpendicular to the nozzle row is a surface of the head chip. The inkjet head according to claim 1, comprising: a groove formed in the groove and a convex portion formed in the manifold fitted into the groove. Of the first position restriction structure, a position restriction structure for restricting movement of the head chip and the manifold in both directions of one axis parallel to the nozzle row is formed in the manifold sandwiching both side surfaces of the head chip. The ink jet head according to claim 1, wherein the ink jet head is composed of both side walls. Of the second position restricting structure, a position restricting structure that restricts movement of the frame and the manifold relative to each other in one uniaxial direction parallel to the chip mounting surface and perpendicular to the nozzle row is provided at the lower end of the frame. 4. The ink jet head according to claim 1, comprising a protrusion formed on the manifold to be engaged. Of the second position restricting structure, a position restricting structure for restricting movement of the frame and the manifold with respect to one direction of one axis parallel to the nozzle row is formed on a step formed at a lower end of the frame, The inkjet head according to claim 1, further comprising a protrusion formed on the manifold that engages with a step. A plate member having an opening, the lower end of the head chip being disposed in the opening, and the lower end surface of the head chip being exposed from the opening; and an elastic claw erected from an edge of the plate member, 5. The structure according to claim 1, wherein the frame, the manifold, and the head chip disposed therebetween are pressed against each other in a direction perpendicular to the chip mounting surface to hold the three members. The inkjet head as described in any one of these. 7. An ink jet printer equipped with the ink jet head according to claim 1, wherein a plane parallel to the chip mounting surface on the back surface of the frame is supported and fixed by the surface. Inkjet printer.

Images