JP2002316419A - Ink jet print head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet print head wherein heat is efficiently radiated even when the ink jet print head is formed on a glass substrate. SOLUTION: A metallic film 16 is formed on the upper face of the glass substrate 15 and a metallic film 17 is formed on the lower face of the glass substrate 15, an insulation film 25, a heating resistor film 26, a heating resistor 26a, an individual wiring electrode 27, a common electrode 28, a partition wall 29 and an orifice plate 31 having an ink ejection nozzle 32 are sequentially laminated on the metallic film 16 on the upper face, and an ink supply groove 33 and an ink supply hole 34 are provided on the glass substrate 15, thereby forming a head section. A through-hole 23 is provided on the glass substrate 15 and a metallic film 24 is formed on the inner wall thereof so that the metallic film 16 and the metallic film 17 on both faces of the substrate 15 are thermally connected with each other by the metallic film 24. The whole ink jet print head 35 is die-bonded to a radiating plate 37 by a die-bonding agent 36. The heat generated on a printing section at the upper face is transferred to the metallic films 16, 24, 17 so that the heat is efficiently radiated to the external section through the radiating plate 37.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet print head for efficiently dissipating heat to the outside.

[0002]

2. Description of the Related Art In recent years, ink jet printers have been widely used. Since the ink jet printer performs printing by ejecting ink as a color material directly to recording paper, it consumes less power and is more economical than an electrophotographic printer using toner, which is a powdered printing material. It is easy to colorize by mixing inks and small in print dots, so high quality and beautiful, low noise, and small size as a whole because image formation is performed only with print head and ink, and good usability. Therefore, it is widely used especially as a personal printer.

[0003] In such a printer, ink is ejected onto a paper surface by a print head (ink-jet print head) provided in a printing section. As a method of ejecting ink to the print head, ink is ejected by deformation of a piezoresistive element. There is a piezo system that blows ink and a thermal system that blows ink by the pressure of film bubbles caused by heat generated by a resistance heating element. The thermal type further has two types of configurations depending on the ink discharge direction.One is a print head called a side shooter type in which the ink is discharged in a direction parallel to the heating surface of the resistance heating element, and the other is There is a print head called a roof shooter type (or a top shooter type) configured to discharge ink in a direction perpendicular to the heat generation surface of the resistance heating element. It is known that the roof shooter type consumes much less power than the side shooter type.

[0004] Speaking of ink jet printers,
Conventionally, a serial printer that prints with a small print head that reciprocates in a direction orthogonal to the paper feed direction has been the mainstream.In recent years, a long print head corresponding to the paper width has been fixed to the apparatus main body, and the paper Attention has been paid to a line printer in which only a sheet is conveyed and printing is performed.

[0005] For example, 90 or more small print heads are collectively formed on a single silicon wafer and cut out individually. Similarly, a long print head is mounted on a single silicon wafer. Even if I try to make it, since the diameter of single crystal silicon is about 6 x 25.4 mm at the maximum,
Even if a long print head is formed on a silicon wafer having such a diameter, only one or two print heads can be collected, and the yield is extremely poor, which is not practical.

Therefore, a ceramic substrate or a glass substrate, which can be increased in size, has attracted attention as a substrate for a long print head. However, since a ceramic substrate or a glass substrate has poor heat radiation characteristics as compared with a silicon substrate, it is necessary to form a heat radiation layer as a base layer.

FIG. 4A is a schematic external plan view of such a long print head, and FIG. 4B is an enlarged view of a portion surrounded by a broken line A in FIG. FIG. 13C is a sectional view taken along the line BB ′ of FIG. The long print head 1 shown in FIGS. 1A, 1B, and 1C has one surface of a large glass substrate 2 (see FIG. 1).
The heat radiation layer 3 is applied to the entire surface (the upper surface in (c)), and the insulating layer 4 is further applied to the entire surface of the heat radiation layer 3. Then, on the insulating layer 4, a heating resistor film 5 patterned into a large number of parallel stripes is formed, and one end of a portion serving as the heating resistor 5a (see FIG. From the right), individual wiring electrodes 6 are formed so as to be individually overlapped on the respective stripes and connected to each other, and a common electrode 7 is overlapped with the other end continuously from the end to all the stripes. Formed and connected.

In FIG. 1C, the common electrode 7 is divided into two sides, but actually, the common electrode 7 is continuous on the front side and the other side of FIG. 1C (up and down in FIG. 2A). ing. That is, the common electrode 7 has a shape in which the center of the rectangular surface is cut out along the longitudinal direction. Then, on these, the substrate 2
Are formed so as to surround the periphery of the heating resistor 5a from three sides.

On the surface of the substrate 2 exposed in the central cutout of the common electrode 7, an elongated ink supply groove 9 having a depth of about 1/3 is formed. Ink supply holes 11 are formed at a plurality of locations on the bottom and communicate with the bottom surface of the substrate 2. An orifice plate 12 is adhered on the uppermost layer having such a structure, that is, on the partition wall 8, and an ink discharge nozzle 13 is formed at a position of the orifice plate 12 facing the heating resistor 5a.

The ink discharge nozzles 13 have a size of, for example, 20 .mu.m.phi. To 40 .mu.m.phi., And thousands of them are arranged in a line to form a nozzle line 14 as shown in FIG. In the example shown in FIG. 1A, the nozzle rows 14 are four rows, and the ink ejection surface of the print head 1 (the orifice plate 1) is formed.
2) is formed. The four nozzle arrays 14 are generally configured to eject black, magenta, cyan, and yellow inks, respectively.

The print head 1 is die-bonded to a parent substrate communicating with an external ink tank, a common electrode 7 is connected to an external power supply terminal, and individual wiring electrodes 6 are connected to respective drive terminals of a drive circuit. Attached to the body. At the time of printing (printing), the heating resistor 5a is selectively energized in accordance with the image information, instantaneously generates heat and generates film bubbles at the interface with the ink.
The ink in the pressurized chamber formed by the partition 8 surrounding the heating resistor 5a from three sides is extruded, and the orifice 13
, And is ejected toward an unillustrated paper surface as an ink droplet.

[0012]

In the heat dissipation to the heat dissipation layer, the heat dissipation property of the heat dissipation layer increases as the thickness of the heat dissipation layer increases. It is possible to obtain the same heat radiation characteristics as in the case, and it is possible to perform stable ink discharge. Particularly, in a configuration in which a large number of heating resistors are arranged, such as a long print head as described above, a large amount of heat is generated as a whole, and thus high heat radiation characteristics are required.

However, if the heat radiation layer is made too thick in order to obtain high heat radiation characteristics, the heat radiation layer is a metal layer, so that the coefficient of thermal expansion is greatly different from that of the glass substrate. And the glass substrate warps. When warpage occurs in the glass substrate, processing accuracy deteriorates, and as a result, the yield decreases. Not only that,
Even after completion, the print quality is reduced due to the warpage of the head,
It also involves the problem of reduced reliability.

[0014] The object of the present invention is to solve the above-mentioned conventional problems.
An object of the present invention is to provide an ink jet print head formed on a silicon substrate or a glass substrate, which can efficiently dissipate heat to the outside and can prevent the glass substrate from warping due to heat.

[0015]

The construction of the ink jet print head according to the present invention will be described below. The inkjet print head of the present invention has a first surface on one side of a substrate.
A heat radiation layer, a heating resistor, an electrode, a partition for separating the heating resistor, and an orifice plate having ink discharge holes are provided, and the heating resistor is heated to generate film bubbles on the surface of the heating resistor. An ink jet print head for discharging ink on the heating resistor from the ink discharge hole by the pressure of the film bubble, wherein a second heat radiation layer provided on the other surface opposite to the one surface of the substrate; A thermal coupling means for thermally coupling the second heat radiation layer and the first heat radiation layer.

The thermal coupling means is constituted by a heat conducting member provided on a wall surface of a through hole provided in the substrate, for example, as described in claim 2. In addition, it is constituted by a heat conducting member filled in a through hole provided in the substrate, and is constituted by, for example, a heat conducting member provided on an end face of the substrate.

Further, the first heat radiation layer and the second heat radiation layer are formed, for example, such that stresses of thermal expansion due to heat generated by the respective heat generating resistors are substantially the same. It is composed.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. FIGS. 1A, 1B, and 1C show a first heat radiation layer, a second heat radiation layer, and a metal film that thermally couples the first heat radiation layer and the second heat radiation layer on the glass substrate of the inkjet print head according to the first embodiment. FIG.
(a) is a plan view showing the shape of the first heat dissipation layer on the glass substrate of the ink jet print head, (b) is an enlarged cross-sectional view taken along the line CC ′ in (a) of FIG. () Is an enlarged sectional view of the completed inkjet print head.

The structure shown in FIGS. 1A and 1B will be described. First, a metal film 16 as a first heat radiation layer is formed on one surface of a glass substrate 15 (the upper surface in FIG. 1B). The metal film 16 includes Cu (copper), Al (aluminum), T
i (titanium) or the like can be used. For example, a multilayer film in which Ti is laminated at 1000Å, Cu is 4.8 μm, and Ti is 1000Å, or a single layer film such as Al is formed with a thickness of 5 μm is formed by sputtering or vacuum. It is formed by vapor deposition or plating.

Next, a metal film 17 as a second heat dissipation layer is formed on the other surface (the lower surface in FIG. 2B) of the glass substrate 15.
The order of forming the metal films 16 or 17 on both surfaces of the glass substrate 15 may be either earlier or later. Also,
The configuration of the metal film 17 on the lower surface may or may not be the same as that of the metal film 16 on the upper surface, as long as the material has excellent thermal conductivity. If the metal films 16 and 17 on the upper and lower surfaces are excellent in thermal conductivity as described above and the stresses due to their thermal expansion are substantially the same, heat during the manufacturing process and furthermore, Metal films 16, 17 and glass substrate 1 due to heat during operation after shipment to
5 can suppress the warpage of the glass substrate 15 caused by the difference in thermal expansion, thereby preventing various problems.

Subsequent to the above, the metal film 16 on the upper surface is provided with an elongated opening 18 at the portion where the ink supply groove is formed, and the same at the portion where the through hole is formed. An opening 19 having a narrow width may be provided, and a square or round opening 21 (see FIG. 1) is formed in the metal film 17 on the lower surface at a portion where an ink supply hole is formed.
(c)), and an elongated opening 22 is provided at a portion where a through hole is to be formed.

At this time, each opening is formed to be slightly larger than each opening of an ink supply groove, an ink supply hole, and a through hole to be formed later in the opening. Thus, when the ink supply groove, the ink supply hole, and the through hole are formed in the subsequent process, the problem of peeling of the metal film from the glass substrate caused by the metal film being drilled together is prevented. be able to.

Subsequently, through holes 23 are formed from the upper and lower surfaces of the glass substrate 15 by, for example, sandblasting or the like to form through holes 23, and the inner walls of the through holes 23 are formed by electroless plating as thermal coupling means. Is formed, and the metal films 16 and 17 on both surfaces of the glass substrate 15 are physically (ie, thermally coupled) to each other.

Subsequently, the structure shown in FIG. 4C is similar to the structure shown in FIG. 4C except that the insulating film 25, the heating resistor film 26, and the heating resistor 26a, the individual wiring electrode 27, the common electrode 28, the partition wall 29, and the orifice plate 31 are sequentially laminated.

The insulating film 25 is made of Si—O
An oxide such as a _two- system or Ta-Si-O system is formed by sputtering or vacuum evaporation. Alternatively, an insulating film of Si—O ₂ , Si—N, or the like is formed by a CVD method. Furthermore, SiO ₂
A system oxide can be formed by an SOG method.

An ink discharge hole 32 is formed in the orifice plate 31 by, for example, plasma dry etching using a helicon wave, and an ink supply groove 33 is newly formed in the glass substrate 15 in addition to the through hole 23 described above. The ink supply holes 34 are formed by sandblasting or the like. Thereby, the ink jet print head 35 is completed.

Further, the entire ink jet print head 35 is die-bonded to the heat radiating plate 37 with the die bonding agent 36 via the metal film 17 on the lower surface, thereby completing a practical unit of the ink jet print head. In this configuration, the heat transmitted to the metal film 16 on the upper surface is
The metal film 24 on the wall surface of the through hole 23 transfers the heat to the metal film 17 on the lower surface, and the heat transferred to the metal film 17 is efficiently radiated to the outside via the heat sink 37.

As described above, even when the ink jet print head 35 is formed on the silicon substrate or the glass substrate 15, the heat generated by the heat generating resistor 26 a as a printing element and the ink is discharged from the ink discharge hole 32. The heat can be efficiently dissipated to the outside, thereby preventing abnormal ejection of ink due to overheating of the residual heat in the preceding heating drive, thereby enabling stable printing to be performed continuously.

FIG. 2A is a plan view showing the shape of the first heat radiation layer on the glass substrate of the ink jet print head according to the second embodiment, and FIG. 2B is the second heat radiation layer. D in the same figure (a) showing the shapes of layers and through holes.
-D 'is an enlarged sectional view taken in the direction of the arrow, and FIG. 3 (c) is an enlarged sectional view of the completed ink jet print head. FIG.
FIGS. 1 (a), 1 (b) and 1 (c) show components necessary for the description in FIGS.
The same components as those shown in FIGS. 1 (b) and 1 (c) are shown in FIGS.
The same numbers as in (b) and (c) are assigned and shown, new components are assigned with new numbers, and numbers that are not particularly required for explanation are omitted.

As shown in FIGS. 2A and 2B, in this embodiment, a metal film 16 as a first heat dissipation layer, a metal film 17 as a second heat dissipation layer, an opening for a through hole are provided. 19, the through hole 23 and the like are formed, but the metal film 24 as shown in FIGS. 1A, 1B and 1C is not formed on the inner wall of the through hole 23. Then, instead of the metal film 24, FIG.
As shown in FIG. 7, the heat conduction member 38 is filled in the through hole 23.

As shown in FIG. 3C, after the ink jet print head 40 completed on the glass substrate 15 is die-bonded to the radiator plate 37, the heat conductive member 38 A device for applying a solder paste for connecting electronic components mounted and mounted on a substrate to circuit terminals onto a circuit board), for example, by pouring a heat transfer paste such as an Ag paste and curing the paste. I do.

As described above, by filling the inside of the through hole 23 with the heat conductive member 38, not only the metal films 16 and 17 on both surfaces of the glass substrate 15 but also the heat radiating plate 37 are directly and widely heated without the interposition of the die bonding agent 36. It becomes possible to combine. Also in this case, the heat radiated from the printing element on the upper surface of the substrate can be efficiently transmitted to the rear surface of the substrate and radiated to the outside.

FIG. 3A is a plan view for explaining a method of manufacturing an ink jet print head according to the second embodiment.
FIG. 1B is an enlarged sectional view of the completed ink jet print head. FIG. 3 (a) shows a plan view of FIG. 1 (c), and the manufacturing method is as described with reference to FIGS. 1 (a), (b) and (c). In FIG. 3 (a), the same components as those in FIGS. 1 (a), (b) and (c) are assigned the same reference numerals as in FIGS. 1 (a), (b) and (c). ing.

As shown in FIG. 3A, the ink jet print head 35 shown in FIG.
After forming the same shape as above and die-bonding it on a large heat sink 37, when cutting out individual head chips for each ink jet print head with a dicing saw or the like, it is indicated by EE 'in FIG. 3 (a). As described above, the main portion 35-1 and the end portion 3 extend along the longitudinal center line of the through hole 23.
5-2, the end 35-2 is discarded, and the main portion 35-2 is discarded.
-1 indicates the ink jet print head 4 shown in FIG.
Let it be 1. FIG. 6B is an enlarged cross-sectional view taken along the line FF ′ after the end 35-2 of FIG.

The shape of the ink jet print head 41 is such that the end face metal film 42 as a heat conducting member is formed on one end face of the glass substrate 15 (the metal film 24 formed on both sides of the inner wall of the through hole 23 in FIG. 3A). (A half surface) is formed. The inkjet print head 41,
Even when formed in this manner, the heat radiated from the printing element on the upper surface of the substrate can be efficiently transmitted to the rear surface of the substrate and dissipated to the outside, and the entire print head can be removed by an amount corresponding to the separation of the end 35-2. Can be formed in a small size, which can contribute to downsizing of the printer body.

[0036]

As described in detail above, according to the present invention, a metal film is formed on both surfaces of a glass substrate and these metal films on the upper and lower surfaces are thermally coupled through through holes. Even when a large amount of heat is generated, such as a long print head, the heat radiated from the printing element can be efficiently transmitted to the back surface of the substrate and dissipated to the outside.
It is possible to provide a highly reliable ink jet print head capable of continuously performing high-quality and stable printing with improved heat radiation characteristics as compared with a print head having a conventional structure.

In addition, since the stress applied to the glass substrate due to the thermal expansion of the heat-dissipating metal film formed on both surfaces of the glass substrate is made equal, the warpage of the glass substrate is prevented. It is possible to suppress the warpage of the glass substrate due to the heat during the process and furthermore, the heat during the actual operation after shipping to the market, thereby preventing various troubles, and providing a more reliable inkjet print head. It becomes.

[Brief description of the drawings]

FIGS. 1A and 1B are diagrams showing shapes of a first heat radiation layer, a second heat radiation layer, and a heat coupling metal film of an ink jet print head according to a first embodiment, and FIG. FIG. 2 is an enlarged cross-sectional view of a completed inkjet print head.

FIG. 2A is a plan view showing a shape of a first heat dissipation layer on a glass substrate of an ink jet print head according to a second embodiment, and FIG. 2B is a view showing a shape of a second heat dissipation layer and a through hole. (A) is an enlarged cross-sectional view taken along the line DD ′ in FIG.
FIG. 3 is an enlarged sectional view of the completed inkjet print head.

FIG. 3A is a plan view illustrating a method for manufacturing an ink jet print head according to a second embodiment, and FIG. 3B is an enlarged cross-sectional view of the completed ink jet print head.

4A is a schematic external plan view of a conventional print head, FIG. 4B is an enlarged view of a portion surrounded by a broken line A in FIG.
(c) is a sectional view taken along the line BB 'of (b).

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Print head 2 Glass substrate 3 Heat dissipation layer 4 Insulating layer 5 Heating resistor film 5a Heating resistor 6 Individual wiring electrode 7 Common electrode 8 Partition wall 9 Ink supply groove 11 Ink supply hole 12 Orifice plate 13 Ink ejection nozzle 14 Nozzle row 15 Glass Substrate 16, 17 Metal film 18, 19, 21, 22 Opening 23 Through hole 24 Metal film 25 Insulating film 26 Heating resistor film 26a Heating resistor 27 Individual wiring electrode 28 Common electrode 29 Partition wall 31 Orifice plate 32 Ink ejection hole 33 Ink supply groove 34 Ink supply hole 35 Ink jet print head 36 Die bonding agent 37 Heat sink 38 Heat conduction member 40, 41 Ink jet print head 42 End face metal film

Claims (5)

[Claims] An orifice plate having a first heat dissipation layer, a heating resistor, an electrode, a partition for separating the heating resistor, and an ink discharge hole is provided on one surface of a substrate, and the heating resistor is heated to generate heat. An ink jet print head that generates film bubbles on a surface of the heating resistor and discharges ink on the heating resistor from the ink discharge holes by pressure of the film bubble, the other surface being opposite to one surface of the substrate. An ink-jet printhead, comprising: a second heat radiation layer provided on a first heat radiation layer; and a thermal coupling unit for thermally coupling the second heat radiation layer and the first heat radiation layer. 2. The ink jet print head according to claim 1, wherein said thermal coupling means is a heat conducting member provided on a wall surface of a through hole provided in said substrate. 3. The ink jet print head according to claim 1, wherein said thermal coupling means is a heat conductive member filled in a through hole provided in said substrate. 4. The ink jet print head according to claim 1, wherein said thermal coupling means is a heat conductive member provided on an end surface of said substrate. 5. The heat radiation layer according to claim 1, wherein the first heat radiation layer and the second heat radiation layer are formed such that thermal expansion stresses caused by heat generated by the heat generating resistors are substantially the same. 2. The ink jet print head according to 1.