JP2012061716A - Ink jet recording head, ink jet recording apparatus, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive ink jet recording head with a small individual liquid chamber substrate.SOLUTION: The ink jet recording head 1000 includes: a nozzle substrate 3 having a plurality of nozzle holes 30 formed therein; the individual liquid chamber substrate 2 having a plurality of liquid chambers (pressure chambers) 21 each corresponding to each nozzle hole of the nozzle substrate and partitioned into individual liquid chambers by side walls, and having a vibration plate 20 configuring a portion of the liquid chambers 21 and an electromechanical transducer 26 integrally formed with the vibration plate; and a driver IC 4 for outputting a driving signal for driving the electromechanical transducer. A partition wall of a gap layer 5 higher in height than the thickness of the electromechanical transducer is formed around the electromechanical transducer 26. An output terminal of the driver IC is bump joined 40 to an input terminal pulled out from the electromechanical transducer in a state of a portion of the driver IC 4 jutting out above the electromechanical transducer. The driver IC is supported by the partition wall of the gap layer 5.

Description

  The present invention relates to an ink jet recording head used in an ink jet recording apparatus, an ink jet recording apparatus including the ink jet recording head, and a printer, a facsimile, a copying apparatus including the ink jet recording apparatus in an image forming unit, or these The present invention relates to an image forming apparatus such as a multifunction peripheral having a function.

  Inkjet recording devices have extremely low noise during recording, high-speed printing is possible, plain paper with a high degree of freedom of ink can be used, and photo-quality images can be formed using glossy paper. It has many advantages. Among them, a so-called ink-on-demand system that discharges ink droplets only when recording is necessary does not require collection of ink droplets that are not necessary for recording, and has become mainstream. The ink jet recording apparatus is used not only as a printer but also in an image forming section of an image forming apparatus such as a facsimile, a copying apparatus, or a multifunction machine having these functions.

  As an example of an ink jet recording head used in such an ink jet recording apparatus, a part of a pressure generating chamber communicating with a nozzle opening for ejecting ink droplets is constituted by a vibration plate, and the vibration plate is deformed by a piezoelectric element to generate pressure. An apparatus is known that pressurizes ink in a generation chamber to eject ink droplets from nozzle openings. Two types of ink jet recording heads have been put into practical use, one using a longitudinal vibration mode piezoelectric actuator that expands and contracts in the axial direction of the piezoelectric element and one using a flexural vibration mode piezoelectric actuator. Yes.

  The former can change the volume of the pressure generating chamber by bringing the end of the piezoelectric element into contact with the diaphragm of the ink jet recording head, and the head suitable for high density printing can be manufactured. There is a problem that the manufacturing process is complicated because it requires a difficult process of cutting into a comb-like shape in accordance with the arrangement pitch of the nozzle openings and an operation of positioning and fixing the cut piezoelectric element in the pressure generating chamber. .

  On the other hand, the latter can flexibly vibrate, although a piezoelectric element can be built on the diaphragm by a relatively simple process of sticking a green sheet of piezoelectric material according to the shape of the pressure generation chamber and firing it. There is a problem that a certain amount of area is required for the use of, and high-density arrangement is difficult.

In order to eliminate the disadvantages of the latter recording head, a uniform piezoelectric material layer is formed by a film forming technique over the entire surface of the diaphragm as seen in Patent Document 1 (Japanese Patent Laid-Open No. 5-286131). In this proposal, a piezoelectric element is formed by dividing the piezoelectric material layer into a shape corresponding to the pressure generating chamber by lithography and forming an independent element for each pressure generating chamber.
This eliminates the need to affix the piezoelectric element to the diaphragm, so that not only can the piezoelectric element be created by a precise and simple technique called lithography, but also the thickness of the piezoelectric element can be reduced. There is an advantage that high-speed driving is possible.

In an inkjet recording head having a configuration in which an integrated circuit for driving a piezoelectric element (hereinafter referred to as a driver IC) is directly mounted on an individual liquid chamber substrate provided with a piezoelectric element and an individual liquid chamber (pressure chamber), a driver has conventionally been used. For example, in Patent Document 2 (Japanese Patent Laid-Open No. 2006-116767), a driver IC is flip-chip bonded between nozzle rows at the center of the chip. However, in this case, a space corresponding to the size of the driver IC must be secured on the chip, and there is a limit to downsizing the chip size.
For this reason, the number of individual liquid chamber substrates made of silicon from one wafer is reduced and the cost is increased. Further, if the chip size is limited, the scanning distance in the main scanning direction becomes long during printing, and the printing speed cannot be increased. Furthermore, there are many problems such as insufficient measures against heat dissipation of the driver IC, which causes a failure.

In Patent Document 3 (Japanese Patent Application Laid-Open No. 2008-036936), a driver IC chip is disposed so as to straddle two rows of diaphragms (actuators). Although the restriction on the size of the individual liquid chamber substrate is reduced, it is necessary to make the width of the driver IC wider than the width of the two rows of diaphragms. Since the number of driver IC chips taken from a single wafer is large and affects the cost, it is necessary to increase the size of the driver IC chip by the size of the diaphragm designed from the inkjet ejection performance. It leads to cost increase.
Further, since there is no structure that supports the two rows of diaphragm portions of the individual liquid chamber substrate, the vibration of the actuator due to the drive propagates to the entire individual liquid chamber substrate and causes mutual interference.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide an ink jet recording head with a small individual liquid chamber substrate and a low cost. It is another object of the present invention to provide an ink jet recording apparatus including the ink jet recording head, and further to provide an image forming apparatus including the ink jet recording apparatus.

In order to achieve the above object, the present invention employs the following means [1] to [8].
[1]: a nozzle substrate having a plurality of nozzle holes, and a plurality of liquid chambers divided into individual liquid chambers by side walls corresponding to the nozzle holes of the nozzle substrate. And a separate liquid chamber substrate having an electromechanical conversion element formed integrally with the vibration plate, and a driver IC that outputs a drive signal for driving the electromechanical conversion element. In the ink jet recording head, a partition wall having a gap layer higher than the thickness of the electromechanical conversion element is formed around the electromechanical conversion element, and a part of the driver IC protrudes onto the electromechanical conversion element The output terminal of the driver IC is bump-bonded to the input terminal drawn out from the electromechanical conversion element, and the driver IC is supported by a partition wall of the gap layer. To (claim 1).
[2]: The ink jet recording head according to [1], wherein the partition walls of the gap layer are formed by patterning a photosensitive resin (claim 2).
[3]: In the ink jet recording head according to [1] or [2], the bump bonding sealant (underfill) is filled along a partition wall of the gap layer ( Claim 3).
[4]: In the ink jet recording head according to [3], the partition is a dam of the sealant (claim 4).
[5]: The ink jet recording head according to any one of [1] to [4], further comprising a dummy bump bonding portion that is not connected to the electromechanical transducer. .
[6]: In the ink jet recording head according to any one of [1] to [5], a power reinforcement line is formed on the individual liquid chamber substrate, and power is supplied to the driver IC via the bump bonding. (Claim 6).
[7]: An ink jet recording apparatus that includes the ink jet recording head according to any one of [1] to [6], and ejects liquid droplets from the ink jet recording head to record an image on a recording medium. (Claim 7).
[8]: An image forming apparatus, wherein the image forming unit includes the ink jet recording apparatus according to [7].

In the ink jet recording head according to [1], the driver IC is connected to the input terminal drawn from the electromechanical conversion element in a state where a part of the driver IC protrudes (overhangs) on the electromechanical conversion element. The output terminals of the individual liquid chamber substrate are bump-bonded, and the driver IC is supported by the partition walls of the gap layer, so that the chip size of the individual liquid chamber substrate is not limited by the area of the driver IC. The size can be reduced and the manufacturing cost can be reduced. Further, the downsizing of the chip can improve the printing speed when mounted on the ink jet recording apparatus. Further, since the driver IC and the individual liquid chamber are close to each other, an effect of radiating heat generated by the driver IC can be obtained.
In addition, since the driver IC is supported by the gap partition walls, the problem that the driver IC fluctuates due to the narrow location of bump bonding to the individual liquid chamber substrate is reduced, and stress concentration on the bump bonding portion is reduced. It is possible to realize an ink jet recording head that prevents and achieves high reliability.

In the ink jet recording head described in [2], since the partition walls of the gap layer are formed by patterning a photosensitive resin, it is possible to easily support the gap of the actuator portion and the driver IC.
In the ink jet recording head according to [3], [4], since the bump bonding sealant (underfill) is filled along the gap layer partition wall, the partition wall is a sealant dam. Thus, the sealant does not flow out to the actuator portion, and an ink jet recording head with high reliability against electrode corrosion due to humidity can be realized.
In the ink jet recording head according to [5], since the dummy bump bonding portion that is not connected to the electromechanical conversion element is provided, the bump bonding portion of the driver IC is biased toward the center, and the driver IC is unstable. Therefore, it is possible to realize a highly reliable ink jet recording head.
In the ink jet recording head described in [6], since the power reinforcement line for supplying power to the driver IC through bump bonding is formed on the individual liquid chamber substrate, when a large number of electromechanical conversion elements are driven simultaneously. By stopping the phenomenon of voltage drop due to the current flowing at once, the discharge performance between the electromechanical conversion elements can be made uniform, and the discharge variation between the nozzles and the image variation are reduced. This improves the image accuracy.

In the ink jet recording apparatus according to [7], since the ink jet recording head having the configuration and effect of any one of [1] to [6] is mounted, manufacturing defects are reduced and cost is reduced. And high-speed printing with a short main scanning distance becomes possible.
In the image forming apparatus described in [8], the inkjet recording apparatus described in [7] is provided in the image forming unit, so that a printer, a facsimile, a copying apparatus capable of performing high-speed printing at low cost, or a function thereof. It is possible to provide a multifunction device or the like having

FIG. 3 is a plan view of the individual liquid chamber substrate of the ink jet recording head according to Embodiment 1 of the present invention viewed from directly above. FIG. 2 is a cross-sectional view taken along line Y-Y ′ of the ink jet recording head of FIG. 1. FIG. 2 is a cross-sectional view taken along line X-X ′ of the ink jet recording head of FIG. 1. FIG. 2 is a flowchart showing a manufacturing process of an inkjet recording head having a cross-sectional structure along the line X-X ′ in FIG. 1. It is the top view which looked at the separate liquid chamber board | substrate of the inkjet recording head which concerns on Example 2 of this invention from right above. It is sectional drawing along the main scanning direction of the inkjet recording head of FIG. It is the top view which looked at the separate liquid chamber board | substrate of the inkjet recording head which concerns on Example 3 of this invention from right above. It is the top view which looked at the separate liquid chamber board | substrate of the inkjet recording head which concerns on Example 4 of this invention from right above. FIG. 10 is a perspective explanatory view showing the inside of an ink jet recording apparatus according to a fifth embodiment of the present invention as seen through. FIG. 10 is a configuration explanatory diagram of a mechanism unit of the ink jet recording apparatus shown in FIG. 9.

  Hereinafter, modes for carrying out the present invention will be described in detail based on the illustrated embodiments.

[Example 1]
FIG. 1 is a plan view of an individual liquid chamber substrate of an ink jet recording head according to Embodiment 1 of the present invention as viewed from directly above. In the figure, the YY ′ line direction is the main scanning direction during recording, and the XX ′ line direction is the sub-scanning direction. FIG. 2 is a cross-sectional view taken along the line YY ′ of the ink jet recording head of FIG. FIG. 3 is a cross-sectional view of the inkjet recording head of FIG. 1 taken along line XX ′.
An ink jet recording head 1000 shown in FIGS. 1 to 3 is a side shooter type head that discharges droplets from nozzle holes 30 provided in a nozzle substrate (hereinafter referred to as a nozzle plate) 3 and is an electromechanical conversion element. This is a system driven by a piezoelectric actuator 26.

As shown in FIGS. 1 to 3, the ink jet recording head 1000 includes three substrates: a common liquid chamber substrate 1, an individual liquid chamber substrate 2, and a nozzle plate 3.
A common liquid chamber substrate 1 is bonded to one of the individual liquid chamber substrates 2 via a gap layer 5, and a nozzle plate 1 is bonded to the other surface of the individual liquid chamber substrate 2. The ink jet recording head is provided with a driver IC 4 (indicated by a broken line in FIG. 1) that supplies a drive signal to the individual electrode 24.

The individual liquid chamber substrate 2 includes a vibration plate 20 that forms a partial wall surface of the pressure chamber 21 that is an individual liquid chamber, and a piezoelectric actuator 26 that is provided on the side facing the pressure chamber 21 via the vibration plate 20. The piezoelectric actuator 26 is formed of a common electrode 23, a piezoelectric body 25 serving as a piezoelectric element, and an individual electrode 24. Note that an insulating layer (not shown) is provided for the portion where the electrode pattern is routed. A partition wall of the gap layer 5 higher than the thickness of the actuator 26 is formed around the piezoelectric actuator 26.
Further, the pressure chamber 21 of the individual liquid chamber substrate 2 communicates with the through hole 11 of the common liquid chamber substrate 1 through the fluid resistance 22. The common liquid chamber substrate 1 is formed of a through hole (ink supply port) 11 for supplying ink to the common liquid chamber 10 and each pressure chamber 21, and a recess 12 in which a driver IC is accommodated.

As shown in FIG. 3, each pressure chamber 21 has an elongated rectangular parallelepiped shape, and is arranged in two rows along the main scanning direction (YY ′ line direction) in FIG. A plurality of lines are arranged along the “line direction” at a resolution of, for example, 300 dpi (dots per inch).
The individual electrode 24 is pulled out from the piezoelectric actuator 26 as shown in FIG. 1 and is electrically connected to a connection terminal (not shown) of the driver IC 4 by a bump bonding 40. At this time, in this embodiment, as shown in FIG. 2, the driver IC 4 protrudes to the actuator 26 on the diaphragm 20 and is supported by the partition walls of the gap layer 5.

  A large number of external connection terminals are formed on the individual liquid chamber substrate 2, and are electrically connected to the bump joints with the external connection terminals of the driver IC by wires (not shown).

In the inkjet recording head 1000 formed as described above, by applying a driving voltage waveform to the individual electrode 24 through the driver IC 4 in a state where each pressure chamber 21 is filled with a liquid, for example, a recording liquid (ink), The piezoelectric element 25 of the actuator 26 contracts in a direction parallel to the diaphragm 20, and as a result, the bending deformation of the diaphragm 20 can be controlled.
Accordingly, the recording liquid (ink) is ejected from the nozzle hole 30 communicating with the pressure chamber 21 by controlling the pressure in the pressure chamber 21 and rapidly increasing the pressure.
After the ink is ejected, the diaphragm 20 returns to the original position, but due to the volume reduction of the ejected ink, the pressure chamber 21 has a negative pressure compared to the common liquid chamber 10, and the fluid resistance 22 part is removed from the common liquid chamber 10. Ink is supplied to the pressure chamber 21 through this. By repeating this, liquid droplets can be continuously discharged, and an image is formed on a recording medium (such as paper) (not shown) disposed facing the ink jet recording head.

Next, a manufacturing method and a specific configuration example of the ink jet recording head 1000 according to the present invention will be described in detail.
This embodiment will be described with reference to FIG. FIG. 4 is a flowchart showing a manufacturing process of the ink jet recording head having a cross-sectional structure along the line XX ′ in FIG.
In this embodiment, an actuator is created by depositing a diaphragm material and a piezoelectric element material on a silicon substrate constituting the individual liquid chamber substrate 2.
First, as shown in FIG. 4A, an SOI (Silicon On Insulator) substrate 2 in which a silicon oxide film of 0.5 μm and silicon of 1.0 μm are bonded to the surface of a 400 μm thick silicon substrate is used as an individual liquid chamber substrate. Use. A silicon oxide film of 0.6 μm is formed on the surface of the SOI substrate 2 by a pyro-oxidation method.
Thereafter, as shown in FIG. 4B, a Pt layer to be a common electrode 23 of the piezoelectric element is formed by sputtering to a thickness of 0.1 μm, and a patterning method using a photolithography technique and an etching technique (hereinafter referred to as a lithoetch method) The common electrode 23 layer is patterned.
Further, a piezoelectric material layer to be the piezoelectric element 25 and the individual electrodes 24 are formed by sputtering by 1.0 μm and 0.1 μm, respectively, and then both films are patterned by the lithoetch method with the same mask, as shown in FIG. As shown, a piezoelectric element portion (piezoelectric actuator) 26 is formed in a portion corresponding to the pressure chamber on the SOI substrate 2.

Next, as shown in FIG. 4D, the gap layer 5 is formed by patterning with a photosensitive resin. The gap layer 5 seals the ink flow path, and a partition wall higher than the thickness of the actuator 26 is formed around the piezoelectric actuator 26. The partition wall thickness becomes a gap, and the space in which the actuator 26 moves. Is forming.
In this embodiment, an epoxy pressure film resist SU-8 (manufactured by Kayaku Microchem) is used. However, the invention is not limited to this as long as liquid contact with ink and an aspect ratio for forming a gap can be obtained. .
Although the thickness of the gap layer 5 is determined by the thickness of the piezoelectric element and the wiring pattern and the operating range of the actuator 26, it has been confirmed that the gap layer 5 operates without any problems with the thickness of the gap layer 5 of about 10 μm implemented this time.

Next, as shown in FIG. 4 (e-1), the driver IC 4 is arranged on the individual electrode substrate 2 via the gap layer 5, and as shown in FIG. The driver IC 4 is bump-bonded to the input terminal drawn from the electrode 24 and the common electrode 23.
At this time, the driver IC 4 is pressed until it hits the partition wall of the gap layer 5. As a result, the driver IC 4 is supported by the partition walls of the gap layer 5 to prevent stress from concentrating on the bump joint.

Next, a common silicon substrate having a structure shown in FIG. 2 in which a recess 22 serving as a fluid resistance 10 and a common liquid chamber 10, a through hole 11 and a recess 12 for housing a driver IC are formed on a separately prepared silicon substrate by lithoetching. The liquid chamber substrate 1 is prepared and bonded to the surface of the individual liquid chamber substrate 2 on the piezoelectric element side as shown in FIG.
The common liquid chamber substrate 1 may be a <110> silicon substrate processed by wet etching using an alkaline etching solution such as TMAH or KOH, or may be replaced with a molded part such as a resin mold or a metal injection mold. It doesn't matter.

Next, the surface of the individual liquid chamber substrate 2 opposite to the piezoelectric element surface is cut by lapping. When the individual liquid chamber substrate 2 is reduced to a thickness of 80 μm, the silicon substrate is anisotropically etched with a predetermined mask to form concave portions to be the pressure chamber 21, the fluid resistance portion 22, and the like, and etching is stopped with SiO ₂ Thus, the diaphragm 20 is formed while leaving a certain thickness (FIG. 4G).
The reason why the individual liquid chamber substrate 2 is thinned by wrapping is to prevent the walls of the pressure chamber 21 from becoming high and causing mutual interference.
In this embodiment, the diaphragm 20 is directly formed on the individual liquid chamber substrate 2 using an SOI substrate. However, the diaphragm 20 is formed by depositing an elastic film on the pressure chamber of the individual liquid chamber substrate 2. May be.

After that, the nozzle substrate 3 in which the nozzle holes 30 are formed by pressing the stainless steel (SUS) material is bonded to the pressure chamber 21 side of the individual liquid chamber substrate 2 as shown in FIG. The ink jet recording head of the example is completed.
In this embodiment, the SUS material obtained by pressing the nozzle holes is used as the nozzle substrate 3, but a nozzle substrate manufactured by a high-speed electroforming method using a sulfamic acid bath may be used.

In this embodiment, the operating range of the actuator 26 is secured by the partition wall of the gap layer 5 and the driver IC 4 is supported on the partition wall of the gap layer 5 by taking advantage of the characteristics of the thin film piezoelectric actuator that functions if a slight gap is formed. As a result, the driver IC 4 can be protruded and disposed on the actuator, and stress can be prevented from concentrating on the bump bonding portion 40 of the driver IC 4. As a result, it is possible to realize an ink jet recording head having a narrow head width, a large number of chips, a low cost and a high reliability.
Further, since the head width can be reduced, it is possible to reduce the size of the ink jet recording apparatus and increase the printing speed by shortening the scanning distance in the main scanning direction.
Further, as shown in FIG. 3, the gap layer 5 has a structure that supports the partition wall 27 on the pressure chamber 21 side. Therefore, when the individual liquid chamber substrate 2 is thinned by wrapping, the gap layer 5 is bent as a whole. The problem is solved.

[Example 2]
5 is a plan view of the individual liquid chamber substrate of the ink jet recording head according to the second embodiment of the present invention as viewed from directly above, and FIG. 6 is a cross-sectional view of the ink jet recording head of FIG. 5 along the main scanning direction. .
In this embodiment, in addition to the configuration of the first embodiment, when the bump bonding portion 40 is protected by the sealant (underfill), the partition walls of the gap layer 5 are guided by the sealant (underfill) (dam). ) And is filled with a sealant.

Supporting the driver IC 4 with the partition walls of the gap layer 5 can prevent stress concentration on the bump joint 40, but if not sealed, the wiring corrodes in addition to the bump joint 40 due to humidity or the like. There is a risk of being.
In this embodiment, since gold bumps are used for bump bonding, it is strong against corrosion and the like, but in order to ensure long-term reliability, the bump bonding portion 40 is sealed with a sealant (underfill). It is preferable.
However, in the case where the driver IC 4 protrudes to the actuator 26, the sealant may flow to the actuator portion and harden, thereby obstructing the operation of the actuator 26.
Therefore, in this embodiment, the partition walls of the gap layer 5 serve as guides (dams) for the sealant, so that the sealant is prevented from flowing into the actuator portion, and a highly reliable ink jet recording head can be realized.
In addition, the sealant has a function of dispersing mechanical stress after curing to relieve stress on the bump bonding portion.

[Example 3]
FIG. 7 is a plan view of an individual liquid chamber substrate of an ink jet recording head according to Embodiment 3 of the present invention as viewed from directly above.
In the present embodiment, in addition to the configuration of the first embodiment or the second embodiment, dummy bumps 41 are provided at locations different from the bump bonding 40 necessary for the electrical connection of the driver IC 4, and the driver IC 4 is connected to the individual liquid. Bonded to the chamber substrate 2. Thus, by providing the junction part by the dummy bump 41, the driver IC 4 can be more securely fixed, and the driver IC 4 can be prevented from becoming unstable due to the bump junction part of the driver IC 4 being biased toward the center. A highly reliable ink jet recording head can be realized.

  In the present embodiment, as in the second embodiment, filling with a sealant (underfill) using the partition walls of the gap layer 5 as a guide is also performed. Thereby, the bump bonding between the driver IC 4 and the individual liquid chamber substrate 2 can be made more reliable, and a highly reliable ink jet recording head can be realized.

[Example 4]
FIG. 8 is a plan view of the individual liquid chamber substrate of the ink jet recording head according to Embodiment 4 of the present invention as viewed from directly above.
In the present embodiment, in addition to the configuration of the first embodiment, a power reinforcement line is provided between the rows of the bump joint portions 40 corresponding to the nozzles of the individual liquid chamber substrate 2 to supply power to the driver IC. It is characterized in that power is supplied to the driver IC 4 through the line at a predetermined interval.

The power reinforcement line is not connected to the other electrode lines of the individual liquid chamber substrate 2, but is connected by bump bonding so that the current on the driver IC 4 side flows.
The reinforcement of the power line prevents the drive voltage to each actuator 26 from dropping due to the resistance value of the power line.
This prevents a difference in ink ejection efficiency depending on the number of drive actuators and a difference in drive voltage applied to the actuator at the end and the actuator at the center, and discharge variation between the actuators (drop velocity Vj and droplet volume Mj). (Dispersion) is reduced.

As described above, in this embodiment, since the power reinforcement line for supplying power to the driver IC 4 via the bump bonding is formed on the individual liquid chamber substrate 2, it flows at a time when a large number of actuators 26 are driven simultaneously. The phenomenon of voltage drop due to current can be prevented, and the discharge performance between the actuators 26 can be made uniform, so that the discharge variation and image variation between nozzles are reduced.
This suppresses the ejection performance (density, etc.) in the recording head, enables image formation with the same dot size, improves image quality, and even when line heads are configured by connecting the heads. Since the discharge performance is uniform, it is possible to suppress uneven density in the portion where the heads are connected.

[Example 5]
Next, an embodiment 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. 9 is a perspective explanatory view showing the inside of the recording apparatus as seen through, and FIG. 10 is a configuration explanatory view of a mechanism part of the recording apparatus.
This ink jet recording apparatus includes a carriage 93 movable in the main scanning direction inside a recording apparatus main body 81, a recording head 94 comprising an ink jet recording head embodying the present invention mounted on the carriage, and ink for supplying ink to the recording head. A printing mechanism 82 composed of a cartridge 95 and the like is housed, and a paper feed cassette (or a paper feed tray) capable of stacking a large number of sheets 83 from the front side in the lower part of the apparatus main body 81 may be used. 84 is removably mounted. Further, the manual feed tray 85 for manually feeding the paper 83 can be turned over. Then, the paper 83 fed from the paper feed cassette 84 or the manual feed tray 85 is taken into the printing mechanism unit 82, and after a required image is recorded by the printing mechanism unit 82, the paper 83 is discharged to the paper discharge tray 86 mounted on the rear side. Make paper.

  The print 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 are subjected to main scanning with a plurality of ink ejection openings (nozzles). It is arranged in a direction that intersects the direction, and is 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 ink jet recording head by force is maintained at a slight negative pressure. Here, the heads 94 of the respective colors are used as the recording heads, but a single head having nozzles for ejecting ink droplets of the respective colors may be used. An ink cartridge in which an ink jet recording head and an ink tank are integrated may be used.

  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). is doing. In order to move and scan the carriage 93 in the main scanning direction, a timing belt 100 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 100 is moved 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 recording 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. The guide member 103 to be transported, the transport roller 104 that reverses and transports the fed paper 83, the transport roller 105 that is pressed against the peripheral surface of the transport roller 104, and the feed angle of the paper 83 from the transport roller 104 are defined. A tip 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 the ejection failure of the recording 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 recording head 94 is capped by the capping unit, 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 recording head 94 is sealed by the capping unit, and bubbles and the like are sucked out together with the ink from the discharge port by the suction unit through the tube. Etc. are removed by the cleaning means, and the ejection failure is recovered. 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.

  Thus, in the ink jet recording apparatus of the present embodiment, since any one of the ink jet recording heads of Embodiments 1 to 4 in which the present invention is implemented is mounted, manufacturing defects are reduced and cost reduction is achieved. Can do. Further, stable ink droplet ejection characteristics can be obtained, and image quality can be improved.

  The ink jet recording apparatus described above can be suitably used as a printer. However, the ink jet recording apparatus is provided in an image forming unit, and an image reading device (scanner) that reads an original image is mounted on the image forming unit. A configuration in which image information of a document image read by a reading device (scanner) is converted into image data for recording by an image processing unit, and an image is formed on a recording medium (paper or the like) by an image forming unit (inkjet recording device). If so, the configuration of the copying apparatus can be obtained. If it is connected to an external line (telephone line, optical line, etc.) with a communication function, it can be used as a facsimile. If it is connected to a local area network (LAN), the functions of a net printer, copier, and facsimile can be used. The image forming apparatus (digital multifunction peripheral) can be configured.

1: Common liquid chamber substrate 2: Individual liquid chamber substrate (SOI substrate)
3: Nozzle plate (nozzle substrate)
4: Driver IC
5: Gap layer 10: Common liquid chamber 11: Through hole (ink supply port)
12: Recess 20: Diaphragm 21: Pressure chamber (individual liquid chamber)
22: Fluid resistance 23: Common electrode 24: Individual electrode 25: Piezoelectric element 26: Piezoelectric actuator 27: Partition 30: Nozzle hole 40: Bump joint 41: Dummy bump 81: Device main body 82: Printing mechanism section 83: Paper (recorded) Medium)
84: Paper feed cassette 85: Manual feed tray 86: Paper discharge tray 91: Main guide rod 92: Secondary guide rod 93: Carriage 93
94: Recording head (droplet discharge head)
95: Ink cartridge 97: Main scanning motor 98: Driving pulley 99: Driven pulley 100: Timing belt 101: Feeding roller 102: Friction pad 103: Guide member 104: Conveying roller 105: Conveying roller 106: Leading roller 107: Sub scanning Motor 109: Printing receiving member 111: Conveying roller 112: Spur 113: Paper discharge roller 114: Spur 115, 116: Guide member 117: Recovery device 1000: Inkjet recording head

Japanese Patent Laid-Open No. 5-286131 JP 2006-116767 A JP 2008-036936 A

Claims (8)

A nozzle substrate in which a plurality of nozzle holes are formed;
Corresponding to each nozzle hole of the nozzle substrate, it has a plurality of liquid chambers divided into individual liquid chambers by side walls, and is formed integrally with a diaphragm constituting a part of the liquid chamber and the diaphragm. An individual liquid chamber substrate having an electromechanical conversion element;
In an inkjet recording head comprising a driver IC that outputs a drive signal for driving the electromechanical transducer,
Around the electromechanical transducer, a gap layer partition wall higher than the thickness of the electromechanical transducer is formed,
An output terminal of the driver IC is bump-bonded to an input terminal drawn out from the electromechanical conversion element with a part of the driver IC protruding on the electromechanical conversion element, and the driver IC is formed on the gap layer. Inkjet recording head characterized by being supported by partition walls The inkjet recording head according to claim 1, wherein
The barrier rib of the gap layer is formed by patterning a photosensitive resin. The inkjet recording head according to claim 1 or 2,
An ink jet recording head, wherein the bump bonding sealant is filled along a partition wall of the gap layer. The inkjet recording head according to claim 3, wherein
An ink jet recording head, wherein the partition wall is a dam of the sealant. The inkjet recording head according to any one of claims 1 to 4,
An ink jet recording head, comprising: a dummy bump bonding portion that is not connected to the electromechanical transducer. The inkjet recording head according to any one of claims 1 to 5,
An ink jet recording head, wherein a power reinforcement line is formed on the individual liquid chamber substrate, and power is supplied to the driver IC through the bump bonding.   An ink jet recording apparatus comprising: the ink jet recording head according to claim 1, wherein an image is recorded on a recording medium by ejecting liquid droplets from the ink jet recording head.   An image forming apparatus comprising the ink jet recording apparatus according to claim 7 in an image forming unit.

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