JP2007062261A - Head module, liquid delivering head, liquid delivering apparatus, and method of manufacturing head module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent unnecessary radiation and change in quality of liquid from occurring by grounding a nozzle sheet by a simple constitution. <P>SOLUTION: An electrode 23 of a head chip 20 is exposed from a region not covered by the nozzle sheet 25 of a head chip positioning hole. A flexible wiring substrate 3 is disposed to cover the exposed electrode 23 of the head chip 20 at the side of a face of a module frame 11 where the nozzle sheet 25 is provided. The electrode 23 of the head chip 20 is electrically connected with a wiring pattern 3a of the flexible wiring substrate 3 via an anisotropic conductive film 28. At the same time, the nozzle sheet 25 is electrically grounded via the module frame 11 and the anisotropic conductive film 28. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a head module that constitutes a part of a head for discharging a liquid, a liquid discharge head and a liquid discharge apparatus using the head module, and a method of manufacturing the head module. More specifically, the present invention relates to a technique for preventing unwanted radiation and liquid alteration by electrically grounding a nozzle sheet.

Conventionally, an ink jet printer has been known as an example of a liquid ejecting apparatus, and various techniques have been disclosed for a head (liquid ejecting head) used in the ink jet printer or the like.
For example, Patent Document 1 discloses a technique for forming a line head by attaching a plurality of head chips to one nozzle sheet.
JP 2002-12747 A

  In the above-mentioned Patent Document 1, a large number of nozzles (ink ejection ports) are formed on one nozzle sheet made of nickel formed by electroforming. A plurality of head chips are affixed to the single nozzle sheet. Further, a head frame in which holes are formed so as to surround the attached head chip is bonded to the nozzle sheet, and the nozzle sheet is supported.

For example, Patent Document 2 discloses a technique in which a single head module including a plurality of head chips is connected and extended by connecting the head modules.
JP 2002-86695 A

  As described above, various techniques relating to the liquid discharge head are known, but on the other hand, there have been the following problems. That is, first, there is a problem of influence on external devices due to unnecessary radiation. And laws and regulations have been established in each country to regulate the obstacle, and FCC is a representative example. In recent years, in particular, the regulations have been strengthened, and there are an increasing number of cases where countermeasures are being pursued when exporting products to other countries.

  Explaining unnecessary radiation, in an inkjet printer, a head chip is one of high-density integrated circuit electronic components, operates with a very small weak current, and is controlled by a pulse signal in a high frequency band. Therefore, electromagnetic waves generated during the operation of the head chip cause electromagnetic induction, and the electric field is generated in the nozzle sheet by the changing magnetic field. In other words, the nozzle sheet replaces the antenna and causes a phenomenon in which radiated unnecessary radiation (EMI) is propagated over a wider range, which may cause malfunction of other adjacent electronic devices depending on the intensity level and frequency. Thus, a wide range of adverse effects on communication media such as televisions and radios, medical devices and control devices can be considered. The problem of unnecessary radiation becomes more prominent as the line head type has a long liquid discharge head.

  The most basic solution for unwanted radiation is to prevent the unwanted radiation from being emitted outside by covering the source with a conductor such as sheet metal to form an enclosure structure. However, in the liquid discharge head of the ink jet printer, the enclosure structure cannot be adopted, and other countermeasures must be taken.

  Second, there is a problem of ink electrolysis due to charging of the nozzle sheet. In other words, the nozzle sheet is arranged at a position facing the conveyed printing paper, and ejects ink droplets from the nozzles. However, the printing paper is generated with various rollers, flaps, and the like in the conveyance path. It may be charged by the influence of friction or static electricity in the equipment. Then, since the nozzle sheet is a metal such as nickel, static electricity charged when the printing paper is conveyed to the side opposite to the nozzle sheet is discharged, and a potential difference is generated between the nozzle sheet and the head chip. In addition, since the conductive ink is filled between the nozzle sheet and the head chip, the electric energy accompanying the potential difference causes both of them to become an electrode plate, which may cause electrolysis. In other words, there is a risk that the nickel on the nozzle sheet that becomes the electrode plate will be ionized and dissolved in the ink that has become a kind of electrolyte solution, the ink will be altered, and the nozzle sheet may be perforated or the shape of the nozzle may be deformed. is there.

Thus, for example, Patent Document 3 discloses a liquid discharge head in which a ground wire is arranged on the nozzle sheet in order to prevent charging of the metal nozzle sheet.
JP 2002-137400 A

For example, in Patent Document 4, a conductive head cover covers the periphery of the liquid discharge head, electrically connects the head cover to the conductive main frame, and includes a conductive portion having a larger electrical resistance value than the head cover. A technique provided is disclosed. The conductive portion allows the electric charge charged in the liquid ejection head to escape to the main frame while suppressing the noise from spreading.
JP 2005-111933 A

However, if ground wires are arranged as described in Patent Document 3 or a new conductive part is provided independently as described in Patent Document 4 for grounding, manufacturing labor and costs are separately derived. However, there are significant disadvantages. In particular, in a modular line head, the influence of unnecessary width radiation and charging of the nozzle sheet is large, and at the same time, countermeasures for it are likely to be complicated in the work process, and to reliably reduce these influences, It's never easy.
Therefore, the problem to be solved by the present invention is to ground the nozzle sheet with a simple configuration to prevent unwanted radiation and liquid alteration.

The present invention solves the above-described problems by the following means.
According to the first aspect of the present invention, a plurality of energy generating elements are arranged substantially linearly at a constant interval on a semiconductor substrate, and the energy generating element is provided on a surface provided with the energy generating elements. A head chip provided with a barrier layer for forming a liquid chamber around the element and an electrode for electrical connection to the outside, a nozzle sheet on which a nozzle is formed, and the electrode of the head chip electrically A wiring board having a wiring pattern to be connected; and a module frame in which a plurality of head chip placement holes larger than the outer shape of the head chip are formed for placing the head chip therein, and generating the energy A head module that discharges the liquid in the liquid chamber from the nozzle by applying a discharge force to the liquid in the liquid chamber by an element; The nozzle sheet is located on one side of the module frame such that the nozzle is located in the head chip arrangement hole and covers a part of the area of the head chip arrangement hole with respect to each head chip arrangement hole. And the head chip is formed in a size that covers a part of the region of the head chip arrangement hole, and the head chip is arranged at a position where the energy generating element of the head chip and the nozzle face each other. As described above, from the other side surface of the module frame, each of the head chip arrangement holes is arranged in each of the head chip arrangement holes, and the electrode of the head chip arranged in the head chip arrangement hole is the nozzle sheet of the head chip arrangement hole. The wiring board is exposed from the area not covered by the nozzle sheet, and the nozzle sheet of the module frame is provided on the wiring board. The exposed surface side is arranged to cover the exposed electrode of the head chip, and the electrode of the head chip and the wiring pattern of the wiring board are electrically connected via an anisotropic conductive film. In addition, the nozzle sheet is electrically grounded via the module frame and the anisotropic conductive film.

  In the above invention, the nozzle sheet is located on one side of the module frame so that the nozzle is located in the head chip placement hole and covers a part of the area of the head chip placement hole with respect to each head chip placement hole. Be placed. Further, the head chip is arranged in each head chip arrangement hole from the other surface of the module frame so that the energy generation element of the head chip and the nozzle are opposed to each other. The wiring board is arranged on the side of the module frame where the nozzle sheet is provided so as to cover the exposed electrode of the head chip, and the head chip electrode and the wiring pattern of the wiring board are anisotropically conductive. The nozzle sheet is electrically connected via the membrane, and the nozzle sheet is electrically grounded via the module frame and the anisotropic conductive film. Therefore, the nozzle sheet can be grounded via the anisotropic conductive film, similarly to the connection between the electrode of the head chip and the wiring pattern of the wiring board.

  The energy generating element of the present invention may be a heating resistor (heating element) such as a heater, a piezoelectric element such as a piezo element, MEMS, or the like, but in the following embodiments, a thermal heating resistor is used. The body 22 corresponds. In the embodiment, the module frame 11 is provided with eight head chip placement holes 11 b, and one head module 10 is provided with eight head chips 20. Then, two head modules 10 are connected in series to form a line head (length of A4 plate), and four rows are provided, and Y (yellow), M (magenta), C (cyan), and A liquid discharge head 1 which is a color line head of four colors of K (black) is formed.

According to the head module of the present invention, the nozzle sheet can be grounded through the anisotropic conductive film in the same manner as the connection between the electrode of the head chip and the wiring pattern of the wiring board.
Therefore, the nozzle sheet can be electrically grounded with a simple configuration without newly providing a ground wire or independently providing a new conductive portion, and unnecessary radiation and liquid alteration can be prevented. .

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a plan view showing a liquid discharge head 1 according to an embodiment of the present invention, as viewed from the liquid discharge surface side. FIG. 2 is a view as seen from the opposite side of FIG. FIG. 3 is a diagram in which the control board 4 is arranged on the front side of FIG.

  The liquid discharge head 1 is used as a head mounted on a liquid discharge apparatus (in this embodiment, a color line inkjet printer). As shown in FIG. 1, the liquid ejection head 1 includes a head frame 2, a flexible wiring board 3, and a plurality of head modules 10. In the plan view of FIG. 1, two head modules 10 are connected in series in the longitudinal direction in the head module arrangement hole 2a, and the two head modules 10 cover the length of the A4 width. One color is printed. The two head modules 10 connected in series are provided in four rows to form a liquid ejection head 1 of four colors (Y, M, C, and K).

Further, eight head chips 20 are provided in each head module 10. FIG. 4 is a cross-sectional view showing the periphery of one head chip 20 in the liquid ejection head 1 according to the embodiment of the present invention.
The head chip 20 includes a semiconductor substrate 21 made of silicon or the like, and a heating resistor 22 (corresponding to an energy generating element in the present invention) deposited on one surface of the semiconductor substrate 21. An electrode 23 is formed on the edge of the semiconductor substrate 21 that is on the same side as the surface on which the heating resistor 22 is formed and opposite to the edge on which the heating resistor 22 is formed. The heating resistor 22 and the electrode 23 are connected via a conductor portion (not shown) formed on the semiconductor substrate 21.

  A barrier layer 24 and a nozzle sheet 25 are laminated on the surface of the head chip 20 on which the heating resistor 22 is formed. The barrier layer 24 forms the side wall of the ink liquid chamber (pressurizing chamber) 26 depending on the thickness in the stacking direction, and serves to bond a head chip 20 and a nozzle sheet 25 described later. The barrier layer 24 is made of, for example, a photosensitive cyclized rubber resist or an exposure curable dry film resist, and is laminated on the entire surface of the semiconductor chip 21 of the head chip 20 on which the heating resistor 22 is formed, and then the photolithography process. Thus, an unnecessary portion is removed by the above. Further, the barrier layer 24 is formed in a substantially concave shape when viewed in plan so as to surround the vicinity of the three sides of the heating resistor 22.

  Furthermore, the nozzle sheet 25 is formed with a plurality of nozzles 25a, for example, formed by an electroforming technique using nickel. In the nozzle sheet 25, more specifically, the central axis of the nozzle 25a and the heat generation so that the position of the nozzle 25a matches the position of the heating resistor 22, that is, the nozzle 25a faces the heating resistor 22. The resistor 22 is bonded to the barrier layer 24 so that the center of the resistor 22 coincides with the plan view.

  The ink liquid chamber 26 is composed of the semiconductor substrate 21, the barrier layer 24, and the nozzle sheet 25 so as to surround the heating resistor 22. The ink liquid chamber 26 is filled with the ink to be ejected, and the ink is applied when the ink is ejected. It becomes a pressure chamber. The surface of the semiconductor substrate 21 on which the heat generating resistor 22 is formed constitutes the bottom wall of the ink liquid chamber 26, and the portion of the barrier layer 24 surrounding the heat generating resistor 22 in a substantially concave shape forms the side wall of the ink liquid chamber 26. The nozzle sheet 25 constitutes the top wall of the ink liquid chamber 26. The ink liquid chamber 26 communicates with a flow path 27 between the head chip 20 and the module frame 11 as shown in FIG.

  The one head chip 20 is usually provided with heating resistors 22 in units of 100, and each of the heating resistors 22 is uniquely selected by a command from a control unit (not shown) of the printer. The ink in the ink liquid chamber 26 corresponding to the heating resistor 22 can be ejected from the nozzle 25 a facing the ink liquid chamber 26.

  That is, when the ink liquid chamber 26 is filled with ink, the heating resistor 22 is rapidly heated by passing a pulse current through the heating resistor 22 for a short time, for example, 1 to 3 μsec. As a result, a gas-phase ink bubble is generated at a portion in contact with the heating resistor 22, and a certain volume of ink is pushed away (the ink boils) due to the expansion of the ink bubble. As a result, ink having a volume equivalent to the pushed ink in the portion in contact with the nozzle 25a is ejected from the nozzle 25a as an ink droplet. The ink droplets are landed on the printing paper to form dots (pixels).

Next, a more detailed structure and manufacturing process of the head module 10 will be described.
FIG. 5A is a plan view showing one module frame 11. The head module 10 according to this embodiment includes a module frame 11, eight head chips 20 and a nozzle sheet 25, and a buffer tank 12.

The module frame 11 is formed in a substantially rectangular shape when viewed in a plan view, and has engaging portions 11a cut out in a substantially L shape on both left and right ends.
The module frame 11 is made of, for example, stainless steel and has a thickness of about 0.5 mm. In this embodiment, substantially rectangular head chip arrangement holes 11b are formed at eight locations. The head chip placement hole 11b has a hole shape slightly larger than the outer shape of the head chip 20, so that the head chip 20 can be completely placed inside.

  The module frame 11 is formed with two attachment holes 11d for fixing to the head frame 2. The attachment hole 11d is used when the head module 10 is attached to the head frame 2. Furthermore, a groove 11c (a hatched portion in FIG. 5A) is formed so as to surround a part of the outer edge portion of each head chip arrangement hole 11b.

  FIG. 5 shows a process of attaching the nozzle sheet 25 to the module frame 11. As shown in FIG. 5, the adhesive 14 is applied (printed) to a region surrounded by the periphery of the head chip arrangement hole 11b and the groove 11c ((b) in the figure). The region of the adhesive 14 is formed in a size that substantially coincides with the outer edge portion of the nozzle sheet 25 when the nozzle sheet 25 is attached. In addition, as shown in FIG. 4, this adhesive 14 is mixed with conductive particles having a particle diameter of about 10 μm and has conductivity.

  And after application | coating of the adhesive agent 14, the nozzle sheet 25 is stuck on the module frame 11 ((c) in a figure). At this time, excess adhesive 14 enters the groove 11c and is absorbed by the groove 11c. Therefore, it is possible to prevent the excessive adhesive 14 from flowing out to the ink ejection surface and blocking the nozzle 25a or obstructing the ejection surface cleaning.

  In addition, the nozzle sheet 25 is formed in a minimum necessary size to be supported by the module frame 11, and when the nozzle sheet 25 is stuck on the head chip arrangement hole 11b, the nozzle sheet 25 is The size is such that it exists only in the application range of the head chip placement hole 11 b and the adhesive 14. That is, the nozzle sheet 25 is formed in the minimum necessary size so as to cover a necessary part of the region of the head chip arrangement hole 11b and to have a minimum adhesion area. Therefore, when the nozzle sheet 25 is attached, a part of the area of the head chip arrangement hole 11b is covered as shown in FIG.

  Furthermore, after the nozzle sheet 25 is stuck, the nozzle sheet 25 and the module frame 11 are electrically connected due to the presence of the conductive particles mixed in the adhesive 14. In addition, since the layer thickness of the adhesive 14 can be made uniform, the adhesive force and the electrical resistance between the nozzle sheet 25 and the module frame 11 can be made substantially the same over the respective portions and locations.

  Further, in the present embodiment, the nozzle sheet 25 is bonded to the module frame 11 by hot pressing by hot pressing. This joining is performed at the highest temperature (for example, about 150 ° C. under the first temperature environment) in the manufacturing process of the head module 10 and the liquid discharge head 1. When the module frame 11 and the nozzle sheet 25 are compared, the nozzle sheet 25 has a larger coefficient of linear expansion (easily expands and contracts due to temperature changes). Below this temperature, the nozzle sheet 25 is stretched by the module frame 11.

That is, the expansion and contraction due to the temperature change of the nozzle sheet 25 is governed by the module frame 11 after the nozzle sheet 25 and the module frame 11 are joined.
Therefore, in order to ensure the rigidity of the module frame 11 as much as possible, it is preferable that the opening area of the head chip arrangement hole 11b of the module frame 11 is minimized. Therefore, the head chip arrangement hole 11 b has an outer shape slightly larger than the head chip 20.

The nozzle 25a is formed by aligning the number of through-holes facing the number of heating resistors 22 in one head chip 20 in one direction.
The nozzle 25a is formed by an excimer laser. Further, since the nozzle 25a formed by the laser beam is tapered, the laser beam is irradiated from the module frame 11 side to form the nozzle 25a. Thus, the nozzle 25a becomes a hole having a taper so that the opening diameter gradually decreases as it approaches the ink ejection surface (the outer surface of the nozzle sheet 25).

  Further, the pitch between the nozzles 25a of the nozzle 25a row located in each head chip arrangement hole 11b is the same as the arrangement pitch of the heating resistors 22 of the head chip 20 (when forming the head module 10 with a resolution of 600 dpi, And about 42.3 μm).

  Furthermore, in FIG. 5, the nozzle 25a row in each head chip arrangement hole 11b is a line connecting the nozzle 25a row in each head chip arrangement hole 11b (a line passing through the center of each nozzle 25a). The line is formed on the center line side of the module frame 11 drawn parallel to the longitudinal direction of the module frame 11. Further, when the head chip arrangement holes 11b are “N1”, “N2”, “N3”,..., “N8” in order from the left side, “N1”, “N3”, “N5” and “N7” The nozzle 25a row in the “th” head chip arrangement hole 11b is formed so as to be aligned on a straight line parallel to the center line. The same applies to the “N2”, “N4”, “N6” and “N8” -th relationships.

Therefore, the nozzle 25a rows in the adjacent head chip arrangement holes 11b, for example, the nozzle 25a rows in the “N1” -th and “N2” -th head chip arrangement holes 11b are on two straight lines parallel to the center line. Align.
In the present embodiment, eight head chip arrangement holes 11b are formed for one module frame 11, but the above relationship is satisfied even when more or fewer head chip arrangement holes 11b are formed. Like that.

  Next, the head chip 20 in which the barrier layer 24 is laminated is arranged and fixed in each head chip arrangement hole 11b. This is performed in a second temperature environment lower than the first temperature environment (for example, at room temperature (about 25 ° C.)). Thereby, the barrier layer 24 and the nozzle sheet 25 are adhered. Here, the head chip 20 is thermocompression bonded while being aligned using a chip mounter. Further, in this case, thermocompression bonding is performed with an accuracy of, for example, about ± 1 μm so that the nozzle 25a is positioned directly below the heating resistor 22 of the head chip 20.

By the way, when the head chip 20 and the nozzle sheet 25 are compared, the nozzle sheet 25 has a larger linear expansion coefficient. The thermocompression bonding temperature of the head chip 20 is lower than the bonding temperature between the module frame 11 and the nozzle sheet 25.
Therefore, when the head chip 20 is thermocompression bonded, the nozzle sheet 25 bonded to the module frame 11 is in a tensioned state, so that the deflection of the nozzle sheet 25 can be prevented and flatness can be ensured.

  Thus, when the head chip 20 on which the barrier layer 24 is formed is arranged in the head chip arrangement hole 11b and the nozzle sheet 25 and the head chip 20 are bonded, the surface of the nozzle sheet 25 on the head chip 20 side, The ink liquid chamber 26 is formed as described above by the barrier layer 24 and the surface of the head chip 20 on which the heating resistor 22 is formed.

  Furthermore, when the head chip 20 is attached to the nozzle sheet 25, the electrode 23 of the head chip 20 is exposed to the outside without being hidden by the nozzle sheet 25 (see FIG. 4). Therefore, electrical connection with the head chip 20 is possible even after the head chip 20 is arranged in the head chip arrangement hole 11b.

  Subsequently, the electrode 23 provided on the head chip 20 side and the flexible wiring board 3 are joined (electrically connected). FIG. 6 is a plan view showing a state in which the flexible wiring substrate 3 is joined after the nozzle sheet 25 and the head chip 20 are attached to the module frame 11. In FIG. 6, the front side is the sticking surface side of the nozzle sheet 25, but for ease of understanding of the drawing, the head chip 20 attached from the opposite side is shown by a solid line (hatched portion). Show. FIG. 7 is a perspective view showing the head chip 20, the nozzle sheet 25, and the flexible wiring board 3.

  As shown in FIG. 7, the flexible wiring board 3 is obtained by applying a wiring pattern 3a and a ground pattern 3b of copper foil to a flexible film-like substrate such as polyimide, and cutting it into a desired shape. Formed. Then, as shown in FIG. 6, two flexible wiring boards 3 are attached to one head module 10. That is, four head chips 20 are arranged in two rows of four, but one flexible wiring board 3 is arranged in each row on the surface side of the module frame 11 where the nozzle sheet 25 is provided. .

  At this time, since the cross section of each wiring pattern 3a is exposed at the tip of the flexible wiring board 3 in the manufacturing process, there is a possibility of short-circuiting between the wiring patterns 3a when contacting the nozzle sheet 25. For this reason, the exposed surface (cross section) of the wiring pattern 3a, which is the outer edge of the flexible wiring board 3, is brought close to the outer edge of the nozzle sheet 25, but as shown in FIG. It is fixed to the module frame 11.

In this state, the flexible wiring board 3 is disposed so as to cover the exposed electrode 23 of the head chip 20, and as shown in FIG. 4, the electrode 23 of the head chip 20 and the electrode (wiring of the flexible wiring board 3) The tip of the pattern 3a) is connected via an anisotropic conductive film 28 (ACF connection).
Therefore, electrical connection between the electrode 23 of the head chip 20 and the wiring pattern 3a of the flexible wiring board 3 is performed.

  Further, the module frame 11 and the ground pattern 3 b of the flexible wiring board 3 are joined (electrically connected) through the same anisotropic conductive film 28. That is, as shown in FIG. 7, the flexible wiring board 3 has ground patterns 3b that are electrically grounded on both outer sides of each wiring pattern 3a connected to each electrode 23 of one head chip 20. ing. And the front-end | tip part of each ground pattern 3b is bent toward the outer side in the position which overlaps with the module frame 11, respectively. Therefore, the module frame 11 and the ground pattern 3b of the flexible wiring board 3 are connected to the common anisotropic conductive film 28 (as in the case of the connection between the electrode 23 of the head chip 20 and the wiring pattern 3a of the flexible wiring board 3). Can be connected via a hatched area in FIG.

  Here, when connecting the module frame 11 and the ground pattern 3b of the flexible wiring board 3, a base jig (not shown) is used. That is, the tip of the ground pattern 3 b of the flexible wiring board 3 is disposed on a protruding pin (not shown) provided on the base jig and is pressed against the module frame 11 via the anisotropic conductive film 28. Then, as shown in FIG. 4, the module frame 11 and the ground pattern 3b of the flexible wiring board 3 are electrically connected.

The nozzle sheet 25 is electrically connected to the module frame 11 due to the presence of conductive particles mixed in the adhesive 14.
Therefore, the nozzle sheet 25 is electrically connected to the ground pattern 3b of the flexible wiring board 3 via the module frame 11 and the anisotropic conductive film 28, and is grounded.

  As a result, even if the electromagnetic wave generated in the head chip 20 causes electromagnetic induction and tries to generate an electric field in the nozzle sheet 25, it is eliminated by grounding through the module frame 11, and the nozzle sheet 25 is replaced with an antenna for unnecessary radiation. Never become. Therefore, it is possible to minimize unnecessary radiation that is generated, and it is possible to reduce adverse effects on communication media such as televisions and radios, medical devices, control devices, and the like.

  Further, the problem of electrolysis due to charging of the nozzle sheet 25 is also solved. That is, even if discharge to the nozzle sheet 25 is performed due to the approach of the printing paper charged with static electricity, the nozzle sheet 25 is not charged because it is grounded. Therefore, there is no potential between the nozzle sheet 25 and the head chip 20, electrolysis does not occur, and ink deterioration and damage to the nozzle sheet 25 are prevented.

  The nozzle sheet 25 can be grounded through an anisotropic conductive film different from the anisotropic conductive film 28 in the wiring pattern 3a of the flexible wiring board 3. Further, instead of electrical connection with the ground pattern 3b of the flexible wiring board 3, it may be grounded by another method.

  Incidentally, the anisotropic conductive film 28 is exposed in the gap between the head chip 20 and the module frame 11 (opposite the flow path 27 shown in FIG. 4). Therefore, as shown in FIG. 4, the gap is sealed with a resin 29 such as an epoxy resin.

  Further, the nozzle surface formed by joining the nozzle sheet 25 and the flexible wiring board 3 to one surface of the module frame 11 has gaps and materials at the ends of the nozzle sheet 25 and the flexible wiring board 3 as shown in FIG. There is a step of several tens of μm, which is a thickness. Furthermore, on the surface of the flexible wiring board 3, the connecting portion between the module frame 11 and the ground pattern 3b is formed with a recess generated by the protruding pin of the base jig when connecting. Therefore, as shown in FIG. 4, these gaps, steps, and dents are sealed with a resin 30 provided from the nozzle sheet 25 side.

Next, as shown in FIGS. 4 and 8, the buffer tank 12 is bonded so as to cover the top of the head chip 20. FIG. 8 is a plan view showing the buffer tank 12 and the flexible wiring board 3.
The buffer tank 12 is a tank for temporarily storing ink, and one buffer tank 12 is provided for one head module 10.

  As shown in FIG. 8, the buffer tank 12 has substantially the same shape as the module frame 11 (see FIG. 6) when viewed in a plan view. And as shown in FIG. 4, the inside of the buffer tank 12 forms the liquid flow path (the dot part in FIG. 4) which became the cavity. In particular, in the liquid discharge head 1 of the present embodiment, the lower surface side (the adhesive surface side with the module frame 11) of the buffer tank 12 is opened, the side walls and the top wall are formed with the same thickness, and the cross section is substantially reverse concave. It is formed to become. Therefore, the buffer tank 12 temporarily stores the ink supplied to the ink liquid chamber 26 and is also a rigid support member for fixing the module frame 11 in the present embodiment.

  When the buffer tank 12 is mounted on the module frame 11, all the head chip arrangement holes 11b are covered. As shown in FIG. 4, the buffer tank 12 and the ink liquid chamber 26 of each head chip 20 are communicated with each other via a flow path 27 between the head chip placement hole 11 b and the head chip 20. Thereby, the buffer tank 12 forms a liquid flow path common to all the head chips 20 in the head module 10.

  Although not shown, a hole is formed in the top wall of the buffer tank 12, and ink is supplied into the buffer tank 12 from an ink tank (not shown) through this hole. Further, the module frame 11, each head chip 20, and the buffer tank 12 have the same linear expansion coefficient. This is because a large difference in coefficient of linear expansion causes troubles such as peeling of the adhesive due to the action of thermal stress, which is avoided.

Furthermore, in the present embodiment, one liquid discharge head 1 is formed by using a plurality of the head modules 10.
As shown in FIG. 1, a rigid head frame 2 is formed with a head module arrangement hole 2a. In this embodiment, eight head modules 10 are arranged side by side in the head module arrangement hole 2a. (Two head modules 10 are connected in series, and the head modules 10 connected in series are arranged in four stages). Each head module 10 is screwed and positioned.

  Further, as shown in FIG. 2, the buffer tanks 12 of the eight head modules 10 are visible on the surface opposite to FIG. The buffer tanks 12 connected in series are connected by a U-shaped tube 13. Further, the connection side end portions (hatched portions in FIG. 2) of the two flexible wiring boards 3 extend perpendicular to the paper surface with respect to one head module 10.

  Next, as shown in FIG. 3, the control substrate 4 for controlling the discharge of the liquid and the like is screwed by screws 5 on the surface side where the buffer tank 12 is provided. On the control board 4, in addition to various capacitors, a connector 4a for connecting to the flexible wiring board 3 is provided. A notch 4b is formed in the vicinity of the connector 4a, and the leading end of the flexible wiring board 3 passes through the notch 4b and goes out from the lower side to the upper side of the control board 4, and the control board 4 connector 4a.

  In this way, two head modules 10 are connected in series to form an A4-compatible line head. Further, four rows of the head modules (consisting of two head modules 10) are arranged to form a color line head corresponding to four colors (colors) of Y, M, C, and K.

As described above, in the present embodiment, electromagnetic waves generated in the head chip 20 are prevented from being radiated by the antenna effect of the nozzle sheet 25, thereby reducing unnecessary radiation radiated from the liquid ejection head 1, Strict regulations can be cleared without adopting major measures such as an enclosure structure.
Accordingly, it is possible to reduce the cost and time required for countermeasures against unnecessary radiation, and it is possible to provide the liquid ejection head 1 that does not adversely affect the operation of communication media such as televisions and radios, medical devices, and control devices.

  Further, since the charging of the nozzle sheet 25 can be prevented, it is possible to prevent a phenomenon in which the conductive ink inside the liquid discharge head 1 serves as an electrolyte and causes electrolysis inside. Therefore, there is no possibility that the ink is denatured, the hole is formed in the nozzle sheet 25, or the shape of the nozzle 25a is deformed.

  Furthermore, the grounding of the nozzle sheet 25 is performed via the module frame 11, the anisotropic conductive film 28, and the ground pattern 3 b of the flexible wiring board 3, so that wiring space can be secured and reliable connection can be achieved. Become. Furthermore, by using the anisotropic conductive film 28 that is originally used for electrical connection between the electrode 23 of the head chip 20 and the wiring pattern 3a of the flexible wiring board 3, the complexity of the work process can be avoided, and Connection and physical connection can be carried out easily and reliably.

FIG. 2 is a plan view showing a liquid discharge head according to an embodiment of the present invention, as viewed from the liquid discharge surface side. It is the figure seen from the surface on the opposite side to FIG. It is the figure which has arrange | positioned the control board to the front side of FIG. FIG. 5 is a cross-sectional view showing the periphery of one head chip in the liquid ejection head according to the embodiment of the present invention. It is a top view which shows the manufacturing process of a head module. It is a top view which shows the state which joined the flexible wiring board after the nozzle sheet and the head chip were affixed on the module frame. It is a perspective view which shows a head chip, a nozzle sheet, and a flexible wiring board. It is a top view which shows a buffer tank and a flexible wiring board.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Liquid discharge head 2 Head frame 2a Head module arrangement | positioning hole 3 Flexible wiring board (wiring board)
3a wiring pattern 3b ground pattern 10 head module 11 module frame 11b head chip placement hole 20 head chip 21 semiconductor substrate 22 heating resistor (energy generating element)
23 Electrode 24 Barrier layer 25 Nozzle sheet 25a Nozzle 26 Ink liquid chamber (liquid chamber)
28 Anisotropic Conductive Film

Claims (5)

A plurality of energy generating elements arranged on a semiconductor substrate in a substantially straight line at regular intervals, and a barrier layer for forming a liquid chamber around the energy generating elements on a surface provided with the energy generating elements; A head chip provided with electrodes for electrical connection with the outside;
A nozzle sheet on which nozzles are formed;
A wiring board having a wiring pattern electrically connected to the electrode of the head chip;
A module frame in which a plurality of head chip placement holes which are holes for arranging the head chips therein and are larger than the outer shape of the head chip are formed,
A head module that discharges the liquid in the liquid chamber from the nozzle by applying a discharge force to the liquid in the liquid chamber by the energy generating element;
The nozzle sheet is located on one side of the module frame so that the nozzle is positioned in the head chip arrangement hole and covers a part of the area of the head chip arrangement hole with respect to each head chip arrangement hole. And is formed in a size that covers a part of the area of the head chip arrangement hole,
The head chip is arranged in each of the head chip arrangement holes from the other surface of the module frame so that the energy generating element of the head chip and the nozzle are opposed to each other.
The electrode of the head chip arranged in the head chip arrangement hole is exposed from a region not covered by the nozzle sheet of the head chip arrangement hole,
The wiring board is arranged on the surface side of the module frame on which the nozzle sheet is provided so as to cover the exposed electrodes of the head chip,
The electrode of the head chip and the wiring pattern of the wiring board are electrically connected via an anisotropic conductive film, and the nozzle sheet is electrically connected via the module frame and the anisotropic conductive film. A head module characterized by being grounded. The head module according to claim 1,
The wiring board has a ground pattern that is electrically grounded,
The head module, wherein the nozzle sheet is electrically connected to the ground pattern of the wiring board. Multiple head modules;
A head frame in which a head module arrangement hole that accommodates a plurality of the head modules is formed, and
The head module is
A plurality of energy generating elements arranged on a semiconductor substrate in a substantially straight line at regular intervals, and a barrier layer for forming a liquid chamber around the energy generating elements on a surface provided with the energy generating elements; A head chip provided with electrodes for electrical connection with the outside;
A nozzle sheet on which nozzles are formed;
A wiring board having a wiring pattern electrically connected to the electrode of the head chip;
A module frame in which a plurality of head chip placement holes which are holes for arranging the head chips therein and are larger than the outer shape of the head chip are formed,
A liquid discharge head that discharges the liquid in the liquid chamber from the nozzle by applying a discharge force to the liquid in the liquid chamber by the energy generating element;
The nozzle sheet is located on one side of the module frame so that the nozzle is positioned in the head chip arrangement hole and covers a part of the area of the head chip arrangement hole with respect to each head chip arrangement hole. And is formed in a size that covers a part of the area of the head chip arrangement hole,
The head chip is arranged in each of the head chip arrangement holes from the other surface of the module frame so that the energy generating element of the head chip and the nozzle are opposed to each other.
The electrode of the head chip arranged in the head chip arrangement hole is exposed from a region not covered by the nozzle sheet of the head chip arrangement hole,
The wiring board is arranged on the surface side of the module frame on which the nozzle sheet is provided so as to cover the exposed electrodes of the head chip,
The electrode of the head chip and the wiring pattern of the wiring board are electrically connected via an anisotropic conductive film, and the nozzle sheet is electrically connected via the module frame and the anisotropic conductive film. A liquid discharge head characterized by being grounded. Multiple head modules;
A head frame in which a head module arrangement hole that accommodates a plurality of the head modules is formed, and
The head module is
A plurality of energy generating elements arranged on a semiconductor substrate in a substantially straight line at regular intervals, and a barrier layer for forming a liquid chamber around the energy generating elements on a surface provided with the energy generating elements; A head chip provided with electrodes for electrical connection with the outside;
A nozzle sheet on which nozzles are formed;
A wiring board having a wiring pattern electrically connected to the electrode of the head chip;
A module frame in which a plurality of head chip placement holes which are holes for arranging the head chips therein and are larger than the outer shape of the head chip are formed,
A liquid discharge device that discharges the liquid in the liquid chamber from the nozzle by applying a discharge force to the liquid in the liquid chamber by the energy generating element;
The nozzle sheet is located on one side of the module frame so that the nozzle is positioned in the head chip arrangement hole and covers a part of the area of the head chip arrangement hole with respect to each head chip arrangement hole. And is formed in a size that covers a part of the area of the head chip arrangement hole,
The head chip is arranged in each of the head chip arrangement holes from the other surface of the module frame so that the energy generating element of the head chip and the nozzle are opposed to each other.
The electrode of the head chip arranged in the head chip arrangement hole is exposed from a region not covered by the nozzle sheet of the head chip arrangement hole,
The wiring board is arranged on the surface side of the module frame on which the nozzle sheet is provided so as to cover the exposed electrodes of the head chip,
The electrode of the head chip and the wiring pattern of the wiring board are electrically connected via an anisotropic conductive film, and the nozzle sheet is electrically connected via the module frame and the anisotropic conductive film. A liquid discharge apparatus characterized by being grounded. A plurality of energy generating elements arranged on a semiconductor substrate in a substantially straight line at regular intervals, and a barrier layer for forming a liquid chamber around the energy generating elements on a surface provided with the energy generating elements; A head chip provided with electrodes for electrical connection with the outside;
A nozzle sheet on which nozzles are formed;
A wiring substrate having a wiring pattern electrically connected to the electrode of the head chip and a ground pattern electrically grounded;
A module frame having a plurality of head chip arrangement holes for arranging the head chip therein,
A method of manufacturing a head module that discharges liquid in the liquid chamber from the nozzle by applying a discharge force to the liquid in the liquid chamber by the energy generating element,
The one surface of the module frame is electrically connected to the module frame, and the nozzle is located in the head chip arrangement hole with respect to each head chip arrangement hole, and the area of the head chip arrangement hole A first step of sticking the nozzle sheet so as to cover a part of
The module is arranged such that the energy generating element of the head chip and the nozzle are opposed to each other, and the electrode of the head chip is exposed from a region not covered by the nozzle sheet of the head chip arrangement hole. A second step of attaching the head chip to each of the head chip placement holes from the other surface of the frame;
The wiring board is disposed on the side of the module frame where the nozzle sheet is provided, and the electrodes of the head chip and the wiring pattern of the wiring board are electrically connected via an anisotropic conductive film. And a third step of electrically connecting the module frame and the ground pattern of the wiring board via the anisotropic conductive film.

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