JP5716431B2 - Inkjet recording head, ink cartridge, inkjet recording apparatus, and image forming apparatus. - Google Patents

Description

  The present invention relates to an ink jet recording head, an ink cartridge, an ink jet recording apparatus, and an image forming apparatus.

  In recent years, printers equipped with inkjet recording heads have been widely used as inkjet printers because of their excellent image quality, low price, and high-speed compatibility (by increasing or decreasing nozzles, they can be used from fast printers to slow printers). It is out. Under such circumstances, further image quality improvement, reliability improvement, cost reduction, and miniaturization have been demanded.

  In order to meet the demand for further improvement in image quality, it has become an indispensable technology to increase the density of nozzles in inkjet recording heads. To that end, there is a need to reduce the size and density of drive ICs as well. It is pressed for. For this reason, in recent years, flip-chip bonding capable of making terminals finer is preferred than wire bonding, which may cause short circuit due to contact between wires or decrease in productivity.

  However, in the case of flip-chip mounting, the drive IC is mounted in a sealed space in the head, so that the drive IC malfunctions due to the heat generated from the drive IC, or the structural material around the drive IC becomes hot. As a result, there was a problem of causing peeling of the joint. Also, as the number of nozzles increases, the amount of heat generated by the drive IC also increases, so efficient heat dissipation of the heat generated by the drive IC is an important issue.

  Various studies have been made to solve such problems. For example, the invention described in Patent Document 1 has a configuration in which the driving IC is flip-chip mounted on the same substrate of the piezoelectric element, and the driving IC includes a heat dissipation member. However, a specific arrangement method of the heat dissipating member has not been actually studied and described. For this reason, there is little possibility that sufficient heat dissipation characteristics can be realized with the configuration described in the document, and since the heat generated by the drive IC cannot be sufficiently dissipated, the drive IC malfunctions and the reliability decreases.

  In the invention described in Patent Document 2, the heat insulating member and the heat radiating member are arranged in this order on the side opposite to the nozzle plate of the substrate on which the piezoelectric element is arranged, and the drive IC is flip-chip mounted on the heat radiating member. IC heat is efficiently dissipated. However, by placing a structure such as a heat radiating plate, a heat insulating plate, or an insulating structure, the electrical connection surface of the drive IC and the electrode of the piezoelectric element are not on the same substrate surface automatically. Therefore, when trying to make a large common liquid chamber, it is inevitable that the wiring is complicated and the distance is increased, the reliability is lowered due to the decrease in the signal-to-noise ratio, the cost is increased due to the increased number of processes, and the wiring is complicated. Leads to a decrease in yield.

  The invention described in Patent Document 3 is an adhesive having a structure in which an electric bonding surface (flip chip bonding) of a driving IC is on the same substrate surface as an electrode of a piezoelectric element, and heat generation of the driving IC is excellent in thermal conductivity. The heat is dissipated to the protective substrate side via According to this configuration, it is necessary to distribute the adhesive uniformly by matching the upper surface of the protective substrate and the upper surface of the drive IC with high accuracy. However, it is difficult to achieve high accuracy in the processing of the driving IC and the protective substrate and in each joining process. For this reason, in practice, characteristic variations are unavoidable due to defects due to defective fixing of the driving IC and heat distribution caused by uneven adhesive. Moreover, even if the adhesive has a high thermal conductivity, the thermal conductivity is 10 (W / m · K) or less, such as copper 398 (W / m · K) and aluminum 236 (W / m · K). In comparison, sufficient heat dissipation performance cannot be secured.

  In view of the above-described problems of the prior art, the present invention effectively discharges heat without adding new parts, and reduces ink ejection characteristic variation due to temperature distribution in the inkjet recording head. It is an object to provide a cartridge, an ink jet recording apparatus, and an image forming apparatus.

To solve the above problems, the present invention includes a liquid chamber base plate having a plurality of individual liquid chambers provided with a piezoelectric element, and a plurality of frames substrate forming the common liquid chamber by laminating, the In the inkjet recording head in which the driving IC is flip-chip mounted on the liquid chamber substrate,
Of the plurality of frame substrates, a frame substrate provided in the vicinity of the drive IC is in contact with the drive IC, and further radiates heat to the ink in the common liquid chamber between the wall surfaces of the common liquid chamber of the frame substrate. There is provided an ink jet recording head characterized in that at least one beam member is integrally formed with a frame substrate.

  According to the present invention, heat can be efficiently released in the short direction of the ink jet recording head chip, and variations in ejection characteristics due to temperature distribution in the ink jet recording head chip can be reduced. Since the frame substrate constituting the common liquid chamber is used as the heat radiating member, an ink jet recording head having good heat radiating characteristics can be realized without generating new members.

1 is a perspective view of an ink jet recording head (droplet discharge head) 100 according to a first embodiment of the present invention, and is a partial cross-sectional view. (A)-(e) is a top view of each member, (f) shows the cross section XX 'of FIG. 1, respectively. FIG. 2 shows a cross section YY ′ of FIG. FIG. 2 shows a cross section YY ′ of FIG. 2 shows an ink cartridge according to the present invention. The perspective explanatory view of the ink jet recording device carrying the ink jet head in the present invention is shown. The side explanatory drawing of the inkjet recording device carrying the inkjet head in this invention is shown.

  Next, examples of the present invention will be described with reference to the accompanying drawings, but the present invention is not limited to the examples.

  1-3 show an example of the ink jet recording head of the present invention. FIG. 1 is a perspective view of an ink jet recording head. FIGS. 2A to 2E are plan views of members, FIG. 1F is a cross-section XX ′ of FIG. 1, and FIG. 3 is a cross-section of FIG. YY ′ is shown.

  As shown in FIGS. 1 to 3, the ink jet recording head 100 in this embodiment includes a nozzle substrate 1, a liquid chamber substrate 12, a liquid supply substrate 7, a frame substrate laminate 9 (9 a to 9 c), a damper film 19, and a reinforcing plate 20. The housing 21 is laminated and each substrate is configured as follows.

  The nozzle substrate 1 is provided with a plurality of nozzles 2.

  The liquid chamber substrate 12 includes a plurality of individual liquid chambers (pressure chambers) 3 divided into individual liquid chambers by side walls, a vibration plate 17, a piezoelectric element 16 formed integrally with the vibration plate 17, and a driving IC 11. A mounting portion and lead wiring 25 are provided. The nozzle substrate 1 is bonded to one side, and the liquid supply substrate 7 is bonded to the other side. The drive IC 11 provided on the liquid chamber substrate is an electronic member that includes at least a drive circuit for a piezoelectric element in a chip integrated circuit such as an IC.

  The liquid supply substrate 7 has an ink supply port 6 for supplying a liquid to the individual liquid chamber (pressure chamber) 3. The liquid chamber substrate 12 is bonded to one side, and the frame substrate stack 9 is bonded to the other side.

  The frame substrate laminate 9 is configured by laminating a plurality of frame substrates and has a common liquid chamber. The number of frame substrates to be stacked is not limited. However, since it is preferable to provide beam members on a plurality of frame substrates, it is preferable that the number of frame substrates is composed of three or more. In this embodiment, a laminated structure including the following three substrates 9a to 9c is illustrated.

The material of the frame substrate is not limited, but a material having good thermal conductivity is preferable, and a material having a thermal conductivity of 100 (W / m · K) or more is more preferable. Specific examples of the material include copper and aluminum.
In the present invention, the drive IC of the piezoelectric element serving as a main heat generation source is in contact with a part of the frame substrate that secures a large contact area with the ink in the common liquid chamber by providing the beam member. For this reason, the frame substrate serves as a heat sink, enabling efficient heat dissipation to the ink.
Here, if the beam member is provided on any of the frame substrates, the above effect can be obtained. However, from the viewpoint of efficiently transmitting heat to the ink, it is preferable to provide a beam member on at least the frame substrate in the vicinity of the driving IC that is a heat generation source so that the transmission path is shortened.

  In general, substances having good thermal conductivity tend to have low solution resistance. Therefore, in order to protect the frame substrate, a liquid contact film (ink resistant protective film) is provided at a position where the ink contacts the ink. It is desirable. The liquid contact film is sufficient if it can give a certain solution resistance (ink resistance), and the material is not limited, but a material that can be easily formed into a thin film is preferably used. For example, gold plating, Ni plating, polyimide And polyparaxylene. Among them, a material having good thermal conductivity is more preferable, and for example, gold plating, Ni plating, and the like are more preferably used.

  By providing the liquid contact film, it is possible to stabilize the physical properties of the ink and prevent the corrosion of the structural material, thereby improving the ink ejection characteristics and reliability.

  In the present embodiment, each of the frame substrates 9a to 9c constituting the frame substrate laminate 9 will be described below.

  In this embodiment, no beam member is provided on the frame substrate 9a in order to widen the movable area of the damper film. However, it is possible to provide the beam members with an interval and number that do not hinder the movable region of the damper film. One side is joined to the frame substrate 9b and the other side is joined to the damper film.

  In the frame substrate 9b, a plurality of beam members are formed at regular intervals integrally with the frame substrate in the common liquid chamber. Here, the beam member in the present invention is a rod-shaped member formed integrally with the frame substrate between the wall surfaces constituting the common liquid chamber in the frame substrate. The number, size, shape, and interval of the beam members provided on the frame substrate are selected in consideration of the heat generation amount of the drive IC, the thermal conductivity of the frame substrate, and the like, and are not limited. However, when a plurality of beam members are provided, the distance between the beam members is preferably set at equal intervals in order to prevent temperature distribution from occurring in the ink in the common liquid chamber. Further, when the beam members are provided on two or more frame substrates, it is preferable to provide the beam members so that the beam members provided on different substrates do not contact each other. This is because it is possible to secure the maximum contact area between the beam member and the ink.

In this embodiment, the frame substrate 9c is a frame substrate provided in the vicinity of the driving IC, and a plurality of beam members are installed at equal intervals integrally with the frame substrate in the common liquid chamber. Here, as with the frame substrate 9b, the number, size, shape, interval, and the like of the beam members are selected in consideration of various conditions and are not limited.
Further, the elastic member 18 formed in a part of the portion corresponding to the drive IC 11 by planar projection has a plate beam structure and is in contact with the upper surface of the drive IC 11. The plate beam portion has a bent structure at the base, and the elastic member 18 is in contact with the upper surface of the drive IC 11 in order to make the contact area with the drive IC 11 as large as possible. At this time, either the elastic member 18 and the drive IC 11 may be in contact with each other or may be bonded. Further, if the base of the plate beam is thinner than the other parts, the elasticity increases and the contact with the driving IC is further facilitated. In addition, although the method of making a part of frame board contact the drive IC 11 as an elastic member was illustrated, the effect of this invention can be acquired if it comprises so that a part of frame board and the drive IC 11 may contact. The specific means is not limited.
One side of the frame substrate 9c is joined to the liquid supply substrate, and one side is joined to the frame substrate 9b. The beam members of the frame substrates 9b and 9c are formed so that the positions thereof are alternate.

  The damper film 19 is a film that performs a pressure relaxation function (damper) in the common liquid chamber 8, and is provided between the frame substrate laminate 9 and the reinforcing plate 20.

  The reinforcing plate 20 is provided for the purpose of securing the movable range of the damper film 19.

  The housing 21 has an ink supply port 22 for supplying ink to the common liquid chamber 8.

  In the ink jet recording head of the present invention composed of the above members, the drive IC 11 mounted by flip chip bonding on the bump formed on the liquid chamber substrate 12 applies a voltage to the piezoelectric element 16 via the lead wiring 25. Then, pressure is generated in the individual liquid chamber 3.

Manufacturing Method A manufacturing method of the ink jet recording head having the configuration of this embodiment will be described below.
(A) A silicon nitride film as a mask is patterned at a place other than the diaphragm 17 on the liquid chamber substrate 12 is provided. Next, a diaphragm 17 that is a multilayer laminated film of polysilicon and SiO ₂ is formed on the liquid chamber substrate 12 by, for example, plasma CVD or pyro-oxidation, which is a means for forming polysilicon and silicon thermal oxide film.
(B) A common electrode 13 made of, for example, Pt, Ti, LNO, or SRO, for example, a piezoelectric body 14 made of, for example, PZT, for example, an upper electrode 15 made of Pt, LNO, or SRO is sequentially formed by a sol-gel method or a sputtering method as thin film forming means. Form.
(C) The upper electrode 15 and the piezoelectric body 14 are patterned by photolithography to form the piezoelectric element 16.
(D) An insulating film (for example, Al ₂ O ₃ ) for preventing discharge of the piezoelectric element 16 is formed on the entire surface. Next, an interlayer insulating film made of, for example, SiO ₂ or SiN is formed on the end portion of the piezoelectric element 16 and the common electrode 13 avoiding the upper electrode 15 so as not to hinder vibration displacement.
(E) Lead wiring 25 made of aluminum is formed at a desired location. (F) Separately, a liquid supply substrate 7 having a recess 26 formed on a silicon substrate by a litho-etching method is manufactured. Glue.
(G) The side opposite to the piezoelectric element forming surface of the substrate 12 is polished to a desired thickness.
(H) The opposite side of the surface of the substrate 12 on which the piezoelectric element is formed is etched by ICP dry etching to form a concave portion that becomes the individual liquid chamber 3, the fluid resistance portion 4, and the ink introduction path 5.
Separately, the nozzle substrate 1 in which the nozzle holes 2 are formed by pressing and polishing SUS is bonded to the recess forming side of the substrate 12.
(I) A separately manufactured drive IC 11 is mounted on the bump 10 provided on the liquid supply substrate 7 side of the liquid chamber substrate 12 by flip chip bonding.
(J) The frame substrates 9a, 9b, and 9c formed by press working and fine cutting are separately joined to manufacture the frame substrate laminate 9, and a liquid contact film is formed, and then joined to the liquid supply substrate 7.
(K) The reinforcing plate 20 provided with the damper film 19 is joined to the frame substrate laminate 9.
(L) A separately manufactured housing is joined on the reinforcing plate.
Through the above steps, the ink jet recording head (droplet discharge head) 100 of this embodiment is completed.

FIG. 4 shows a second embodiment of the present invention.
Parts and portions having the same functions as those in the first embodiment are indicated by the same numbers.
In addition to the contents of the first embodiment, a filler 27 having good thermal conductivity is sealed in a space surrounded by the driving IC 11, the liquid supply substrate 7, the frame substrate 9c, and the liquid chamber substrate 12. As the filler having good thermal conductivity, those having higher thermal conductivity than air are preferable, and those having a thermal conductivity of 10 (W / m · K) or more are more preferable. For example, a metal such as aluminum or copper, or a resin mixed with carbon can be used.

Next, an ink cartridge according to the present invention will be described with reference to FIG.
This ink cartridge is obtained by integrating the ink jet recording head 61 according to any of the above embodiments having the nozzles 2 and the like, and the ink tank 62 that supplies ink to the ink jet recording head 61.
In this way, in the case of an ink tank integrated head, the cost reduction and reliability improvement of the head immediately lead to the cost reduction and reliability improvement of the entire ink cartridge. Therefore, as described above, the cost reduction and high reliability are achieved. By reducing the manufacturing defects, the yield and reliability of the ink cartridge can be improved, and the cost of the head-integrated ink cartridge can be reduced.

  Next, an example of an ink jet recording apparatus equipped with the ink jet recording head according to the present invention will be described with reference to FIGS. 6 is a perspective explanatory view of the recording apparatus, and FIG. 7 is a side explanatory view of a mechanism portion of the recording apparatus.

  This ink jet recording apparatus includes a carriage movable in the main scanning direction inside the recording apparatus main body 81, a recording head composed of an ink jet recording head embodying the present invention mounted on the carriage, an ink tank for supplying ink to the recording head, and the like. A printing mechanism section 82 and the like are housed, and a paper feed cassette (or a paper feed tray) 84 that can stack a large number of sheets 83 from the front side is detachably attached to the lower portion of the apparatus main body 81. In addition, the manual feed tray 85 for manually feeding the paper 83 can be opened, the paper 83 fed from the paper feed cassette 84 or the manual feed tray 85 is taken in, and the printing mechanism unit 82 is loaded. After recording a required image, the paper is discharged to a paper discharge tray 86 mounted on the rear side.

The printing mechanism 82 holds a carriage 93 slidably in the main scanning direction by a main guide rod 91 and a sub guide rod 92 which are guide members horizontally mounted on left and right side plates (not shown). (Y), cyan (C), magenta (M), and black (Bk) ink jet recording heads according to the present invention for ejecting ink droplets of each color, the head 94 includes a plurality of ink ejection openings (nozzles) in the main scanning direction And are mounted with the ink droplet ejection direction facing downward. In addition, each ink cartridge 95 for supplying ink of each color to the head 94 is replaceably mounted on the carriage 93.
The ink cartridge 95 has an air port that communicates with the atmosphere above, a supply port that supplies ink to the ink jet recording head below, and a porous body filled with ink inside. The ink supplied to the inkjet head is maintained at a slight negative pressure by force. Further, although the heads 94 of the respective colors are used here as the recording heads, a single head having nozzles for ejecting ink droplets of the respective colors may be used. Further, as described in the third embodiment, the ink cartridge can integrate the ink tank and the ink jet recording head.

  Here, the carriage 93 is slidably fitted to the main guide rod 91 on the rear side (downstream side in the paper conveyance direction), and is slidably mounted on the sub guide rod 92 on the front side (upstream side in the paper conveyance direction). doing. In order to move and scan the carriage 93 in the main scanning direction, a timing belt 200 is stretched between a driving pulley 98 and a driven pulley 99 that are rotationally driven by a main scanning motor 97, and the timing belt 200 is attached to the carriage 93. The carriage 93 is driven to reciprocate by forward and reverse rotation of the main scanning motor 97.

  On the other hand, in order to convey the paper 83 set in the paper feed cassette 84 to the lower side of the head 94, the paper feed roller 101 and the friction pad 102 for separating and feeding the paper 83 from the paper feed cassette 84 and the paper 83 are guided. A guide member 103, a transport roller 104 that reverses and transports the fed paper 83, a transport roller 105 that is pressed against the peripheral surface of the transport roller 104, and a leading end that defines a feed angle of the paper 83 from the transport roller 104 A roller 106 is provided. The transport roller 104 is rotationally driven by a sub-scanning motor 107 through a gear train.

  A printing receiving member 109 is provided as a paper guide member that guides the paper 83 sent from the transport roller 104 below the recording head 94 in accordance with the movement range of the carriage 93 in the main scanning direction. A conveyance roller 111 and a spur 112 that are rotationally driven to send the paper 83 in the paper discharge direction are provided on the downstream side of the printing receiving member 109 in the paper conveyance direction, and the paper 83 is further delivered to the paper discharge tray 86. A roller 113 and a spur 114, and guide members 115 and 116 that form a paper discharge path are disposed.

  At the time of recording, the recording head 94 is driven according to the image signal while moving the carriage 93, thereby ejecting ink onto the stopped sheet 83 to record one line. Record the line. Upon receiving a recording end signal or a signal that the trailing edge of the paper 83 has reached the recording area, the recording operation is terminated and the paper 83 is discharged.

  Further, a recovery device 117 for recovering defective ejection of the head 94 is disposed at a position outside the recording area on the right end side in the movement direction of the carriage 93. The recovery device 117 includes a cap unit, a suction unit, and a cleaning unit. The carriage 93 is moved to the recovery device 117 side during printing standby and the head 94 is capped by the capping means, and the ejection port portion is kept in a wet state to prevent ejection failure due to ink drying. Further, by ejecting ink that is not related to recording during recording or the like, the ink viscosity of all the ejection ports is made constant and stable ejection performance is maintained.

  When a discharge failure occurs, the discharge port (nozzle) of the head 94 is sealed with a capping unit, and bubbles and the like are sucked out from the discharge port with the suction unit through the tube. Is removed by the cleaning means to recover the ejection failure. Further, the sucked ink is discharged to a waste ink reservoir (not shown) installed at the lower part of the main body and absorbed and held by an ink absorber inside the waste ink reservoir.

  As described above, since the inkjet head embodying the present invention is mounted in this inkjet recording apparatus, there is no ink droplet ejection failure due to vibration plate drive failure, stable ink droplet ejection characteristics are obtained, and image quality is improved. improves.

  Although only the ink jet recording apparatus has been described here, the image forming apparatus can be configured by arranging the ink jet recording apparatus in an image forming unit and combining with an external device such as a control device.

3. Individual liquid chamber (pressure chamber)
6). Ink supply port 7. Liquid supply substrate 8. Common liquid chambers 9a to 9c. Frame substrate 11. Driving IC
12 Liquid chamber substrate 16. Piezoelectric element

JP 2007-112062 A JP 2006-289963 A JP 2006-116767 A

Claims (9)

A liquid chamber board having a plurality of individual liquid chambers provided with a piezoelectric element, and a plurality of frames substrate forming the common liquid chamber by laminating, drive I C in the liquid chamber on the substrate flip chip In the mounted inkjet recording head,
Of the plurality of frame substrates, a frame substrate provided in the vicinity of the drive IC is in contact with the drive IC, and further radiates heat to the ink in the common liquid chamber between the wall surfaces of the common liquid chamber of the frame substrate. An ink jet recording head, wherein at least one beam member for forming the head is formed integrally with a frame substrate. 2. The frame substrate according to claim 1, further comprising three or more frame substrates, wherein a beam member for radiating heat to the ink in the common liquid chamber is provided at least on the frame substrate near the drive IC. Inkjet recording head.   The inkjet recording head according to claim 1, wherein the beam members are formed on the frame substrate at regular intervals.   4. The beam member is provided on a plurality of frame substrates, and the beam members are arranged so that the beam members provided on different frame substrates do not contact each other. 2. An ink jet recording head according to 1.   The ink jet recording head according to claim 1, wherein a portion of the frame substrate that comes into contact with ink is covered with a liquid contact film. Between the Ekishitsumoto plate and frame substrate has a liquid supply board having the ink supply port for supplying liquid to the individual liquid chamber, the drive IC, the liquid supply board, 3 of the frame board 6. The ink jet recording head according to claim 1, wherein a filler is enclosed in a space where all of the surfaces are formed.   The ink jet recording head according to any one of claims 1 to 6, wherein the ink jet recording head is an ink cartridge in which an ink jet recording head for ejecting ink droplets and an ink tank for supplying ink to the ink jet recording head are integrated. An ink cartridge comprising a head.   8. An ink jet recording apparatus that performs recording on a recording medium by discharging droplets from a head portion of the ink cartridge, wherein the ink cartridge includes the ink cartridge according to claim 7.   An image forming apparatus comprising the ink jet recording apparatus according to claim 8 in an image forming unit.

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