JPH1134309A - Ink jet recording device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent electric leakage to an adjacent channel by connecting a flexible print cable to an electrode formed on a board of an ink jet head by solder connection, and specifying a thickness of the solder, thereby preventing scattering of solder by the solder connection. SOLUTION: Solder 64 is formed in films at both ends of electrode patterns 61, 62 of a flexible print cable(FPC cable) 53, and the patterns 61, 62 of the cable 53 are solder connected to a common electrode and individual electrodes of a board. Here, a thickness of the solder 64 formed in the films at ends of the patterns 61, 62 of the cable 53 is necessarily 5±3 μm. Thus, the thickness of the solder 64 is set to a range of 5±3 μm to prevent a decrease in yield due to electric leakage to an adjacent channel by scattering the solder while maintaining a connecting strength. A pitch of the patterns 61, 62 of the cable 53 is about 100 μm, and a pattern width is about 50 μm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording apparatus, and more particularly to an ink jet recording apparatus in which an electromechanical transducer is provided on a substrate and a flexible printed cable is connected to electrodes on the substrate by soldering.

[0002]

2. Description of the Related Art In general, an ink jet head constituting a recording head of an ink jet recording apparatus used for a printer, a facsimile, a copying machine, etc. has a plurality of nozzle holes for discharging ink droplets, and an ink liquid chamber corresponding to each nozzle hole. (Also referred to as a “pressurized liquid chamber”), and energy generating means such as an electromechanical conversion element such as a piezoelectric element or an electrothermal conversion element such as a heater for pressurizing the ink in the ink liquid chamber. By driving in accordance with the recording signal, the ink in the required ink liquid chamber is pressurized to eject ink droplets from the nozzle holes.

Here, as an ink jet head using an electromechanical transducer such as a piezoelectric element, for example, Japanese Unexamined Patent Publication No.
As described in JP-A-142324, a plurality of stacked piezoelectric elements are joined and arranged on a substrate in a plurality of rows, and a frame member located around the piezoelectric element is joined, and A diaphragm having a diaphragm is laminated on the piezoelectric element and the frame member, and a pressurized liquid chamber which is pressurized on the diaphragm by the laminated piezoelectric element through the diaphragm and ink is supplied to the liquid chamber. A liquid chamber partition member forming an ink supply path is laminated, and a nozzle plate having a nozzle formed thereon is further laminated on the liquid chamber partition member, and ink droplets are ejected from the nozzles by displacement of the laminated piezoelectric element in the d33 direction. There is something like that.

In order to use an ink jet head using the displacement of the laminated piezoelectric element in the direction d33, it is necessary to provide an end face electrode at both end faces of the head where the internal electrodes of the laminated piezoelectric element are alternately connected and the laminated piezoelectric element. It is necessary to electrically connect with a driver (drive IC) to apply a drive waveform. Therefore, for example, in the ink jet head described in the above-mentioned publication, a common electrode pattern and an individual electrode (selection electrode) pattern are formed on a substrate on which a multilayer piezoelectric element is fixed, and the multilayer piezoelectric element and each electrode pattern are electrically conductive. Electrically connected with a flexible adhesive or the like, and a flexible printed cable (hereinafter, referred to as “FPC cable”) is soldered to each electrode pattern of the substrate, and the FP
An electrical connection is made by connecting the C cable to the driver.

[0005]

When an electrode pattern is formed on a substrate on which a piezoelectric element is provided as in the above-described ink jet head, and the electrode pattern and the FPC cable are connected by soldering, As the nozzle density increases, the distance between the electrodes becomes shorter, which may cause electrical leakage to adjacent channels due to the scattering of solder.
If the thickness of the solder is reduced to reduce the scattering of the solder, mechanical bonding strength may be insufficient, and peeling may occur.
Furthermore, the solder flows out from the common electrode pattern of the FPC cable to form agglomerates, which fall off and cause a short circuit or the like.

[0006] The present invention has been made in view of the above points, and an object of the present invention is to improve the yield by avoiding inconvenience caused by soldering.

[0007]

According to a first aspect of the present invention, there is provided an ink jet recording apparatus which pressurizes ink in an ink liquid chamber by a displacement of an electromechanical transducer disposed on a substrate, and pressurizes the ink from a nozzle. In an ink jet recording apparatus provided with an ink jet head for discharging ink droplets, a flexible printed cable was joined to electrodes formed on the substrate of the ink jet head by soldering, and the thickness of the solder was set to 5 ± 3 μm.

According to a second aspect of the present invention, in the inkjet recording apparatus of the first aspect, the pitch of the electrode patterns provided on the flexible printed cable is 120 μm or less, and the pattern width is 60 μm or less.

According to a third aspect of the present invention, there is provided an ink jet recording apparatus having an ink jet head for discharging ink droplets from nozzles by pressurizing ink in an ink liquid chamber by displacement of an electromechanical transducer disposed on a substrate. A flexible printed cable is joined to the electrode formed on the substrate of the inkjet head by soldering, and at least the soldered portion of the common electrode pattern of the flexible printed cable is formed in a mesh shape or a plurality of fine wire patterns.

According to a fourth aspect of the present invention, there is provided an ink jet recording apparatus having an ink jet head for discharging ink droplets from nozzles by pressurizing ink in an ink liquid chamber by displacement of an electromechanical transducer disposed on a substrate. A flexible printed cable is joined to the electrodes formed on the substrate of the inkjet head by soldering, and the thickness of the common electrode pattern of the flexible printed cable is smaller than that of the individual electrode patterns.

[0011]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is an exploded perspective view showing an example of an ink jet head of an ink jet recording apparatus to which the present invention is applied, FIG. 2 is an enlarged cross-sectional view of a main part of the head in a direction orthogonal to a channel direction (nozzle arrangement direction), and FIG. FIG. 3 is an enlarged cross-sectional view of a main part of a head in a channel direction.

This ink jet head includes a drive unit 1, a liquid chamber unit 2, and a head cover 3. The drive unit 1 is configured such that a plurality of laminated piezoelectric elements 12 as energy generating means are arranged in two rows and joined on a ceramic substrate, for example, an insulating substrate 11 such as barium titanate, alumina, or forsterite. A frame member 13 made of resin, ceramic, or the like surrounding the periphery of each of the two rows of piezoelectric elements 12 is joined by an adhesive 14.

The plurality of piezoelectric elements 12 are provided between piezoelectric elements 17 (to be referred to as "driving units") to which driving pulses for applying ink to droplets and flying are provided, and driving units 17, 17. A piezoelectric element (hereinafter, referred to as a “non-driving unit”) serving as a liquid chamber support member that is located and receives a driving pulse and simply fixes the liquid chamber unit 2 to the substrate 11.
... are alternately configured.

Here, as the piezoelectric element 12, a laminated piezoelectric element having ten or more layers is used. This laminated piezoelectric element has a thickness of 10 to 50 μm / 1, for example, as shown in FIG.
Layer of lead zirconate titanate (PZT) 20 and a thickness of several μ
An internal electrode 21 made of silver / paradium (AgPd) of m / 1 layer is alternately laminated, but the material used for the piezoelectric element is not limited to the above, and other electromechanical conversion elements may be used. Can also.

The internal electrodes 21 of each piezoelectric element 12 are left and right end face electrodes 22 and 23 made of AgPd every other layer (the opposing face sides of the two piezoelectric element rows are end face electrodes 22, and the non-opposing face sides are end face electrodes). 23). On the other hand, as shown in FIG.
Each pattern of the common electrode 24 and the individual electrode 25 is provided by Au plating, AgPt paste printing, AgPd paste printing, or the like.

The opposite end face electrodes 22 of each row of the piezoelectric elements 12 are connected to the common electrode 24 via a conductive adhesive 26.
On the other hand, the non-opposing end surface electrodes 23 of the piezoelectric elements 12 in each row are connected to the individual electrodes 25 via the conductive adhesive 26 in the same manner. Thereby, the driving unit 17
When a drive voltage is applied to the drive unit 17, an electric field is generated in the stacking direction, and the driving unit 17 is displaced in the stacking direction (d 33).
Direction displacement) occurs. As shown in FIG. 2, the common electrode 24 has a hole 13a formed in the frame member 13.
By filling the inside with the conductive adhesive 26, the pattern connected to each piezoelectric element is conducted.

On the other hand, the liquid chamber unit 2 includes a diaphragm 31 made of a metal material, a resin, or the like, and a dry film resist (D).
FR), a liquid chamber partition member 32 of a two-layer structure formed of a photosensitive resin layer of FR, and a nozzle plate 33 of a metal material.
Are sequentially laminated and heat-sealed. By each of these members, one piezoelectric element 12 (driving unit 17)
And a diaphragm portion 34 corresponding to the one piezoelectric element 12, a pressurized liquid chamber 35 pressurized through each diaphragm portion 34, and a pressurized liquid chamber located on both sides of the pressurized liquid chamber 35. Common liquid chambers 36, 36 for introducing ink to be supplied to 35
One channel is formed by the ink supply passages 37 and 37 communicating the pressurized liquid chamber 35 and the common liquid chambers 36 and 36, and a nozzle 38 communicating with the pressurized liquid chamber 35. Two rows are provided.

The diaphragm 31 is formed of a metal material, for example, a Ni plating film by an electroforming method, a resin, or the like.
The diaphragm part 34 corresponding to the driving part 17, the beam 41 joined to the non-driving part 18 and the base 42 joined to the frame member 13 are formed. Diaphragm part 34
Are the island-shaped convex portions 43 joined to the driving portion 17 and the convex portions 4
3 and a thin film portion (diaphragm region) 44 having a thickness of about 3 to 10 μm.

The liquid chamber partition member 32 is formed by laminating a dry film resist on the diaphragm 31 side in advance, exposing it using a required mask, and developing it to form a first photosensitive resin layer 45 having a predetermined liquid chamber pattern. And a second photosensitive resin layer 46 having a predetermined liquid chamber pattern formed by laminating a dry film resist in advance on the nozzle plate 33 side, exposing using a required mask, and developing the predetermined liquid chamber pattern. Become.

The nozzle plate 33 is formed of a metal material, for example, a Ni plating film by an electroforming method, and has a large number of nozzles 38 which are fine discharge ports for flying ink droplets. The inner shape (inner shape) of the nozzle 38 is formed in a horn shape (may be a substantially columnar shape or a substantially truncated cone shape). The diameter of the nozzle 38 is about 25 to 35 μm on the ink droplet outlet side.

The ink discharge surface (nozzle surface side) of the nozzle plate 33 is a water-repellent surface 47 which has been subjected to a water-repellent surface treatment as shown in FIG. For example, PTF
Ink physical properties such as E-Ni eutectoid plating, electrodeposition coating of fluororesin, vapor-deposited evaporative fluororesin (for example, pitch fluoride), baking after solvent application of silicon resin or fluorine resin The water-repellent treatment film selected according to the above is provided to stabilize the ink droplet shape and the flying characteristics so that high-quality image quality can be obtained. The periphery of the nozzle plate 33 is a non-water-repellent surface 48 on which no water-repellent film is formed.

The substrate 11 of the drive unit 1 and the piezoelectric element 12 and the frame member 13 are assembled by bonding with an adhesive 49, and the liquid chamber unit 2 is processed and assembled separately from the drive unit 1. After that, the vibration plate 31 of the liquid chamber unit 2 and the piezoelectric element 12 and the frame member 13 of the drive unit 1 are joined with an adhesive 50 to form an ink jet head.

The substrate 11 is supported and held on a spacer member (head holder) 51 serving as a head supporting member, and a head driving I / D provided in the spacer member 51 is provided.
C and the electrodes 24 and 25 connected to the piezoelectric elements 12 (drive unit 17) of the drive unit 1
They are connected via PC cables 53,53. In addition,
Electrodes 24 and 25 on substrate 11 and FPC cables 53 and 5
3 will be described later.

The nozzle cover (head cover) 3
Is made of a metal material formed in a box shape to cover the periphery of the nozzle plate 33 and the side surface of the head.
An opening is formed corresponding to the water-repellent surface 47 of the nozzle plate 33, and is bonded to the non-water-repellent surface 48 remaining on the peripheral portion of the nozzle plate 33 with an adhesive. Further, in order to supply ink from an ink cartridge (not shown) to the liquid chamber, a spacer member 51, a substrate 11,
The frame member 13 and the diaphragm 31 are provided with ink supply holes 54 to 57, respectively.

In the ink jet head configured as described above, by applying a drive waveform (pulse voltage of 10 to 50 V) to the drive unit 17 in accordance with the recording signal, a displacement in the stacking direction occurs in the drive unit 17, Diaphragm 31
The pressurized liquid chamber 35 is pressurized through the diaphragm section 34 of the above, and the pressure rises, and ink droplets are ejected from the nozzle 38. At this time, ink flows also in the direction of the ink supply passages 37, 37 leading from the pressurized liquid chamber 35 to the common liquid chamber 36. However, by reducing the cross-sectional area of the ink supply passages 37, 37, the fluid resistance portion is reduced. Function to reduce the flow of ink toward the common liquid chambers 36, 36, thereby preventing a drop in ink ejection efficiency.

Then, with the end of the ink droplet ejection, the ink pressure in the pressurized liquid chamber 35 decreases, and a negative pressure is generated in the pressurized liquid chamber 34 due to the inertia of the ink flow and the discharge process of the drive pulse. To the ink filling process. At this time, the ink supplied from the ink tank flows into the common liquid chambers 36, 36, and from the common liquid chambers 36, 36 to the ink supply paths 37, 3.
After that, it is filled into the pressurized liquid chamber 35. Then, the vibration of the ink meniscus surface near the outlet of the nozzle 38 is attenuated,
When the ink is returned to the vicinity of the outlet of the nozzle 38 due to surface tension (refill) and reaches a stable state, the operation shifts to the next ink droplet ejection operation.

Next, the joining of the FPC cable 53 and the electrodes 24 and 25 on the substrate 11 in this ink jet head will be described with reference to FIG. As shown in FIG. 4, the FPC cable 53 includes a common electrode pattern 61 connected to the common electrode 24 on the substrate 11 and an individual electrode pattern 62 connected to the individual electrode (selection electrode) 25 on the substrate 11, formed of a polyimide film 63. It is formed between 63. The electrode patterns 61 and 62 of the FPC cable 53
Is about 100 μm and the pattern width is about 50 μm.

Then, a solder 64 is formed on the ends of the electrode patterns 61 and 62 of the FPC cable 53,
The electrode patterns 61 and 62 of the cable 53 are soldered to the common electrode 24 and the individual electrodes 25 of the substrate 11. here,
The thickness of the solder 64 formed on the ends of the electrode patterns 61 and 62 of the FPC cable 53 is 5 ± 3 μm.

By setting the thickness of the solder 64 to 5 ± 3 μm as described above, it is possible to prevent the solder from being scattered and causing an electric leak to an adjacent channel, thereby reducing the yield, while maintaining the bonding strength. That is, when the pitch of the electrode patterns 61 and 62 of the FPC cable 53 is 120 μm or less and the pattern width becomes 60 μm or less, the normal 10
When the thickness of the solder is set to about μm, the solder is scattered at the time of soldering, causing a leak between adjacent channels. If the amount of the solder is too small, peeling of the bonded portion occurs due to insufficient mechanical strength.

By setting the pitch of the electrode patterns 61 and 62 of the FPC cable 53 to 120 μm or less and the pattern width to 60 μm or less, a high-density multi-nozzle head can be obtained with a high yield.

Next, another embodiment of the present invention will be described with reference to FIGS. In this embodiment, the solder film forming portion (solder applying portion) 61a of the common electrode pattern 61 of the FPC cable 53 is formed in a mesh shape. By doing so, it is possible to prevent the generation of solder lumps at the time of soldering. Instead of forming the solder film forming section (solder applying section) 61a in a mesh shape, a plurality of fine line patterns may be used.

That is, since the common electrode pattern 61 has a large pattern width and a large amount of solder, the solder flows during soldering, and the solder particles 65 easily form as shown in FIG. The agglomerate 65 is used for other patterns or the substrate 1
Electrical leakage may occur due to contact with other electrode patterns on one side. By forming the solder application portion 61a in a mesh shape, the amount of solder can be reduced, generation of agglomerates is prevented, electric leakage is reduced, and yield is improved.

Next, still another embodiment of the present invention will be described with reference to FIG. In this embodiment, the thickness of the solder 64a formed on the solder film forming portion (solder coating portion) of the common electrode pattern 61 of the FPC cable 53 is set to the individual electrode pattern 6
The thickness is smaller than the thickness of the solder 64b formed on the second solder film forming section. Also in this case, the amount of solder of the common electrode pattern 61 can be reduced, the generation of agglomerates is prevented, the electric leakage is reduced, and the yield is improved. This embodiment is particularly effective when the width of the common electrode pattern is small.

[0034]

As described above, according to the ink jet recording apparatus of the first aspect, the flexible printed cable is joined to the electrode formed on the substrate of the ink jet head by soldering, and the thickness of the solder is set to 5 ± 3 μm. Therefore, it is possible to prevent the solder from being scattered due to the solder bonding, to prevent the electric leakage to the adjacent channel, and to improve the yield.

According to the ink jet recording apparatus of claim 2, in the ink jet recording apparatus of claim 1,
Since the pitch of the electrode patterns provided on the flexible print cable is 120 μm or less and the pattern width is 60 μm or less, a highly reliable high-density multi-nozzle head can be obtained.

According to the ink jet recording apparatus of the third aspect, the flexible printed cable is joined to the electrode formed on the substrate of the ink jet head by soldering, and at least the soldered portion of the common electrode pattern of the flexible printed cable is meshed or formed. Since a plurality of fine line patterns are formed, it is possible to prevent the formation of agglomerates due to the flow of solder, and to prevent electrical leakage to adjacent channels, thereby improving the yield.

According to the ink jet recording apparatus of the present invention, the flexible printed cable is joined to the electrodes formed on the substrate of the ink jet head by soldering, and the solder thickness of the common electrode pattern of the flexible printed cable is adjusted to the solder thickness of the individual electrode pattern. Because it was thinner than the thickness,
The formation of agglomerates due to the outflow of solder can be prevented, the electric leakage to adjacent channels can be prevented, and the yield can be improved.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing an example of an inkjet head of an inkjet recording apparatus according to the present invention.

FIG. 2 is an enlarged sectional view of a main part of the head in a direction orthogonal to a channel direction.

FIG. 3 is an enlarged sectional view of a main part of the head in a channel direction.

FIG. 4 is an explanatory view of a main part of an FPC cable showing one embodiment of the present invention.

FIG. 5 is an explanatory view of a main part of an FPC cable showing another embodiment of the present invention.

FIG. 6 is an explanatory diagram of agglomerate formation by solder flowing out.

FIG. 7 is an explanatory view of a main part of an FPC cable showing another embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Drive unit, 2 ... Liquid chamber unit, 3 ... Nozzle cover, 11 ... Substrate, 12 ... Piezoelectric element, 13 ... Frame member, 24 ... Common electrode, 25 ... Individual electrode, 32 ... Liquid chamber partition member, 33 ... Nozzle Plate, 42: diaphragm, 53: F
PC cable, 61: Common electrode pattern, 61a: Solder coating part, 62: Individual electrode pattern, 64, 64a, 64
b: Solder.

Continued on the front page (72) Inventor Masayuki Iwase 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Company (72) Inventor Seiji Nagaba 1-3-6 Nakamagome, Ota-ku, Tokyo Ricoh Company (72) Inventor Noboru Nakane 1-3-6 Nakamagome, Ota-ku, Tokyo Ricoh Co., Ltd. (72) Inventor Tsutomu Sasaki 1-3-6 Nakamagome, Ota-ku, Tokyo Ricoh Co., Ltd.

Claims (4)

[Claims] 1. An ink jet recording apparatus having an ink jet head for discharging ink droplets from nozzles by pressurizing ink in an ink liquid chamber by displacement of an electromechanical transducer disposed on a substrate. An ink jet recording apparatus, wherein a flexible printed cable is joined to the formed electrode by soldering, and the thickness of the solder is set to 5 ± 3 μm. 2. The ink jet recording apparatus according to claim 1, wherein the pitch of the electrode patterns provided on the flexible printed cable is 120 μm or less, and the pattern width is 60 μm or less. 3. An ink jet recording apparatus comprising an ink jet head for discharging ink droplets from nozzles by pressurizing ink in an ink liquid chamber by displacement of an electromechanical transducer disposed on a substrate. An ink jet recording apparatus, wherein a flexible printed cable is joined to the formed electrode by soldering, and a soldered portion of a common electrode pattern of the flexible printed cable is formed in a mesh shape or a plurality of fine line patterns. 4. An ink jet recording apparatus having an ink jet head for discharging ink droplets from nozzles by pressurizing ink in an ink liquid chamber by displacement of an electromechanical transducer disposed on a substrate. An ink jet recording apparatus, wherein a flexible printed cable is joined to the formed electrodes by soldering, and the solder thickness of a common electrode pattern of the flexible printed cable is smaller than the solder thickness of an individual electrode pattern.