JPH06191027A - Ink jet recording head and apparatus - Google Patents

Abstract

PURPOSE:To provide an ink jet recording head not receiving the restriction of a film forming device and a film forming condition and easily reconciling film quality and the film forming condition. CONSTITUTION:A protective layer is provided to a base plate 11 so as to cover electrodes 14 and a heating part 10 for the purpose of preventing the electrolytic corrosion or electrical dielectric breakdown of the heating part 10 and the electrodes 14 due to the contact with ink or the penetration of the ink and consists of first, second and third protective layers 15, 16, 17 successively arranged from the side of the electrothermal converter consisting of the electrodes 14 and the heating part 10. The first protective layer 15 is the lowermost layer among three protective layers and covers both of the heating part 10 and the electrodes 14 and the exposed part of the base plate 11 so as to insulate them and contains SiO2 doped with impurities as a main component.

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 head for ejecting ink droplets from an ejection port for recording, and an ink jet recording apparatus having the ink jet recording head.

[0002]

2. Description of the Related Art With regard to an ink jet recording head of this type, for example, an ink jet recording method described in JP-A-54-51837 obtains a driving force for ejecting ink droplets by causing thermal energy to act on ink. In this respect, it has a feature different from other inkjet recording methods. That is, in the recording method disclosed in the above-mentioned publication, the ink subjected to the action of heat energy is heated to generate bubbles, and the action force based on the generation of the bubbles causes the ink liquid to be ejected from the ejection port at the tip of the inkjet recording head. A feature is that droplets are ejected and fly, and the ink droplets adhere to the recording member to record information.

In the ink jet recording head applied to this recording method, generally, an ejection port provided for ejecting ink and thermal energy for ejecting an ink droplet in communication with the ejection port act on the ink. A liquid discharge part having a liquid flow path having a heat acting part as a part thereof, a heating resistor as an electrothermal converter which is means for generating heat energy, and an upper protection for protecting them from ink. It has layers.

By the way, in this recording method, since the ink is bubbled at a short interval, the heating resistor must be driven at a very high temperature at a very short interval, and the heating resistor and the protective film on it must be driven. Very high temperature stability is required. To solve this problem, the heating resistor has been developed exclusively for it.

Regarding the protective layer, it is known that the thermal stress durability varies depending on the amount of argon in the film, and it has been proposed to set the amount of argon in the film within a certain range. The existing proposal is to set the amount of argon within the specified range by specifying the film forming apparatus, the film forming conditions, etc., and improve the thermal stress durability.

[0006]

In the above-mentioned conventional ink jet recording head, by defining the film forming apparatus, the film forming conditions, etc., it can be achieved only with a specific apparatus and specific conditions. It was difficult to achieve compatibility with film quality such as coverage. In addition, there are restrictions on the device, which is disadvantageous in reducing the device cost and increasing the size of the device.

An object of the present invention is to provide an ink jet recording head which does not have restrictions on the film forming apparatus and film forming conditions and which can easily achieve both film quality and film forming conditions, and an ink jet recording apparatus including the same. .

[0008]

In order to achieve the above object, an ink jet recording head of the present invention has an ejection port for ejecting ink, a liquid path communicating with the ejection port, and a liquid path corresponding to the liquid path. An electrothermal converter that is provided and that generates thermal energy to generate bubbles in the ink in the liquid path by the thermal energy to eject the ink from the ejection port; and at least protect the electrothermal converter from the ink. In an inkjet recording head having one protective layer, at least the protective layer on the electrothermal converter side of the protective layers has a main component of SiO ₂ , and is doped with impurities.

In the ink jet recording head of the present invention,
It is possible to use one in which the impurities are phosphorus or boron. It is preferable that each of these is doped with 0.1 to 10 atom% of phosphorus or 0.5 to 5 atom% of boron.

Further, the ink jet recording head of the present invention may be of a full line type in which a plurality of ejection openings are provided over the entire width of the recording area of the recording medium.

The ink jet recording apparatus of the present invention comprises the ink jet recording head of the present invention and a conveying means for conveying a recording medium, and ejects ink from the ejection port of the ink jet recording head based on a recording signal. It is characterized by performing recording.

[0012]

By doping the impurities, the mixing of argon during the film formation is suppressed and falls within the specified range, thereby improving the thermal stress durability. Therefore, there are no restrictions on the film forming conditions, and it is possible to select film forming conditions that match other film qualities. Further, there are no restrictions on the film forming apparatus.

[0013]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 1 is a plan view showing a heater board portion which is a main part of an embodiment of an ink jet recording head of the present invention, FIG. 2 is a sectional view taken along line XX of FIG. 1, and FIG. 3 is a view of this embodiment. FIG. 3 is a fragmentary perspective view showing the configuration of an inkjet recording head.

Ink jet recording head 20 of this embodiment
As shown in FIG. 3, a large number of minute ejection ports 31 for ejecting ink, a heater 21 that is an electrothermal converter that is provided for each ejection port 31 and generates thermal energy,
The liquid passage 30 is provided for each ejection port 31 and includes a liquid passage 30 that is in communication with the ejection port 31 and includes a heat acting portion that applies thermal energy of an electrothermal converter to the ink to generate bubbles in the ink. . The inkjet storage head 20 is provided with a common liquid chamber 28 that is provided in common to each liquid passage 30 for supplying ink to each liquid passage 30, and the common liquid chamber 28,
A top plate 26 is integrally provided on each of the liquid passages 30 and each of the discharge ports 31. The discharge port 31 is, for example, 1
128 or 256 or more can be formed at a high density of 6 / mm, and a full line type can be formed by forming the number only over the entire width of the recording area of the recording medium. .

The heater 21 is formed on the substrate 11 by the heating resistor 1 made of a material having a certain volume resistivity.
3 is provided in a U-shape, and an electrode 14 made of a material having good electric conductivity is laminated on the heating resistor 13. The heating resistor 13 is, for example, hafnium boride (HfB).
₂ ) and the like, and a metal, for example, aluminum, can be used as a material forming the electrode 14. The electrode 14 has almost the same shape as the heating resistor 13, but a part is missing, and this missing part becomes the heating part 10 (see FIGS. 1 and 2). A current flows through 13 to generate heat. In the heater 21, after a film made of a material forming the heating resistor 13 and a film made of a material forming the electrode 14 are provided on the substrate 11 by sputtering, the electrode 1 is formed by a photolithography process.
It suffices to form a portion where 4 is missing. The portions where the electrodes 14 are missing are formed on the substrate 11 so as to be located at the bottoms of the corresponding liquid passages 30, respectively.

As shown in FIG. 2, the substrate 11 is composed of a substrate 18 made of, for example, silicon and a heat storage layer 12 formed by subjecting the surface of the substrate 18 to a thermal oxidation treatment. Although not shown in FIG. 3, as shown in FIG. 1 and FIG.
4 and the heating portion 10 so as to cover these electrodes 14
A protective layer that protects the heat generating portion 10 is provided. This protective layer is provided for the purpose of preventing electrical corrosion or electrical insulation breakdown of the heat generating portion 10 and the electrode 14 due to contact with the ink or permeation of the ink, and the electric heat generating layer including the electrode 14 and the heat generating portion 10 is provided. It is composed of three layers of a first protective layer 15, a second protective layer 16, and a third protective layer 17 in order from the converter side.
The first protective layer 15 is provided as a lowermost layer of the three protective layers so as to cover and insulate both the heat generating portion 10 and the electrode 14 and the exposed portion of the substrate 11. The main component is SiO ₂ and impurities are doped. As the impurities, elements such as phosphorus and boron can be used. And these impurities are
Phosphorus is 0.1 to 10 atomic%, more preferably 0.5 to 5
Atomic%, 0.5 to 5 atomic% for boron, more preferably 1
It is preferably doped at 3 atom%.

The second protective layer 16 is made of, for example, tantalum (T
a) and the like and is provided by a method such as a bias sputtering method. The third protective layer 17 is to be the uppermost layer of the three protective layers, is made of, for example, an organic resin such as photosensitive polyimide, and is formed on almost the entire surface excluding the vicinity of the heat generating portion 10.

Next, the operation of this ink jet recording head will be described. First, ink is supplied from an ink tank (not shown) to the common liquid passage 28 shown in FIG. The ink supplied into the common liquid chamber 28 is supplied into each liquid passage 30 by a capillary phenomenon, and is stably held by forming a meniscus at each ejection port 31 at the tip of each liquid passage 30. Here, by causing a current to flow through a predetermined electrode 14 based on a recording signal provided from a control unit (not shown), the heat generating unit 10 shown in FIGS. 1 and 2 generates heat,
The ink is heated and foams via the first protective layer 15 and the second protective layer 16, and the energy of the foaming ejects ink droplets from the ejection ports 31 corresponding to the predetermined electrodes 14.

Next, the ink jet recording head of the present invention will be described in more detail with reference to experimental examples and comparative examples.

First, on the silicon as the base 18, SiO ₂ is formed to 2.0 μm as the heat storage layer 12 by thermal oxidation to form the substrate 11. Next, as the heating resistor 13, HfB ₂ is deposited to a thickness of 0.1 μm by sputtering. Further, as the electrode 14, Ti is deposited by 0.005 μm and Al is deposited by 0.6 μm. Then, a plurality of U-shaped circuit patterns as shown in FIG. 1 are formed by the photolithography technique to form the heat generating portion 10 of 30 μm × 150 μm. Next, SiO ₂ mixed with the impurities shown in Table 1 as the first protective layer 15 (Experimental Examples 1 to 3 are phosphorus-containing glass PSG, Experimental Examples 4 to 7 are boron-containing glass BSG, and Comparative Examples 1 and 2 are 99). 0.99% SiO ₂ ) under the conditions shown in Table 1 (sputtering power 2.0 kW, sputtering pressure 0.2 Pa, 2.0
A film thickness of 2.0 μm is formed by the bias sputtering method (bias voltage 100 V).

[0022]

[Table 1] Next, Ta is used as the second protective layer 16 by sputtering to 0.5.
A μm film is formed, and a bar-shaped pattern as shown in FIG. 1 is formed by a photolithography technique. Finally, photosensitive polyimide is applied as the third protective layer 17 to form a pattern formed on almost the entire surface except for the vicinity of the heat generating portion 10 shown in FIG. In this way, the heater board is completed.

The amount of argon in the film of the heater board completed in this way was measured by EPMA (Electro Prob).
It was measured by Micro Analysis). The measurement results are shown in Table 2. In Table 2, CST is Constant
Shows Stress Test.

[0024]

[Table 2] The amount of argon in the film was 7.0, 3.0% in Comparative Examples 1 and 2, and 0.4, 0.6, 0.7 in Experimental Examples 1 to 7, respectively.
%Met.

Next, an evaluation test of durability against heat stress was performed with a drive disconnection pulse.

The test conditions are as follows.

Driving frequency 5.0 kHz Rectangular pulse width 10 μsec Driving voltage Foaming voltage × 1.4 (1.4 in Table 2)
The results are shown in Table 2. Comparative Example 1 has 10 ⁷ pulses,
Comparative Example 2 is broken at 10 ⁶ pulses, whereas Experimental Examples 1 to 7 are broken at 10 ⁸ pulses. Therefore, the heat stress durability is improved by 1 to 2 digits as compared with the conventional one. When the heat stress durability is good as described above, the degree of freedom in selecting the pulse width and the like is increased, and the durability is also improved. In Comparative Examples 1 and 2,
When the sputtering pressure is different from 2.0 Pa and 0.2 Pa, the amount of argon in the film is different. However, in Experimental Examples 2 and 3,
Even if the sputtering pressure is different from 2.0 Pa and 0.2 Pa, the amount of argon in the film has the same value. Therefore, if the SiO ₂ is doped with impurities, the amount of argon in the film will be the same even if the film forming conditions are different. Therefore, the film forming condition can be determined from other film qualities (residual stress, step coverage). It will be possible. That is, it becomes easy to achieve compatibility between these film qualities and film forming conditions. Further, this suggests that the amount of argon in the film is the same even when the device is changed. When actually forming a film with the same target material as in Experimental Example 1 using another device, the same amount of argon in the film was observed. Was the amount. Therefore, it is very advantageous for reducing the cost of the apparatus and introducing a large-sized apparatus.

Next, an ink jet recording apparatus having the ink jet recording head 20 shown in FIGS. 1 to 3 will be described with reference to FIG.

FIG. 4 is a perspective view of an essential part showing an embodiment of the ink jet recording apparatus of the present invention.

In FIG. 4, an ink jet recording head 20 for ejecting ink based on a recording signal given from a control unit (not shown) to record a desired image is shown in the above-mentioned embodiment of the ink jet recording head of the present invention. It has the same structure as the one.

The carriage 102 on which the ink jet recording head 20 is mounted has two guide shafts 103 and 10.
4 is slidably fitted in the direction of arrow I, and is coupled to a part of a timing belt 108 wound around a pulley 107 fixed to an output shaft of a carriage motor 105 and a pulley 106 rotatably supported. ing. The inkjet recording head 20 is configured so that the pulley 107 rotates in the forward direction and the reverse direction by the driving force of the carriage motor 105, and the timing belt 108 rotates in the forward direction and the reverse direction, and reciprocates in the arrow I direction.

The recording paper 109, which is a recording medium, is guided by a paper pan 110 and is conveyed by a paper feed roller (not shown) which is pressed against a pinch roller. This conveyance is performed using the paper feed motor 116 as a drive source. The conveyed recording paper 109 is ejected by the paper ejection roller 11
Tension is added by 3 and spur 114,
The paper holding plate 112 formed of an elastic member causes the heater 1 to
Since it is pressed against 11, it is conveyed while being in close contact with the heater 111. The inkjet recording head 2 is based on a recording signal supplied from a control unit (not shown).
The recording paper 109 to which the ink ejected by 0 adheres is
The ink that has been heated by the heater 111 has its water content evaporated and is fixed on the recording paper 109.

The recovery system unit 115 is for maintaining the ejection characteristics in a normal state by removing foreign matters and ink of high viscosity adhering to the ejection port (not shown) of the ink jet recording head 20. Is. The recovery system unit 115 is provided with a cap 118a,
The ejection ports of the inkjet recording head 20 are capped to prevent clogging. The cap 118
An ink absorber 118 is arranged inside a. Further, on the recording area side of the recovery system unit 115, cleaning for contacting with the surface of the inkjet recording head 20 on which the ejection port is formed and cleaning foreign matter and ink droplets adhering to the surface on which the ejection port is formed. Blade 11
7 is provided.

The present invention is particularly effective in an ink jet recording head and a recording apparatus for recording by forming flying droplets by utilizing thermal energy among the ink jet recording systems.

Regarding the typical structure and principle thereof, for example, US Pat. Nos. 4,723,129 and 4740 are applicable.
What is done using the basic principles disclosed in 796 is preferred. This method can be applied to both the so-called on-demand type and continuous type, but especially in the case of the on-demand type, liquid (ink)
By applying at least one drive signal to the electrothermal converter arranged corresponding to the sheet or liquid path in which is stored, which corresponds to the recorded information and causes a rapid temperature rise exceeding nucleate boiling. , It is effective because it generates heat energy in the electrothermal converter and causes film boiling on the heat-acting surface of the recording head, resulting in the formation of bubbles in the liquid (ink) corresponding to this drive signal on a one-to-one basis. Is. The liquid (ink) is ejected through the ejection openings by the growth and contraction of the bubbles to form at least one droplet. It is more preferable to make this drive signal into a pulse shape, because the bubble growth and contraction are immediately and appropriately performed, so that the ejection of the liquid (ink) with excellent responsiveness can be achieved.

As the pulse-shaped drive signal, those described in US Pat. Nos. 4,463,359 and 4,345,262 are suitable. If the conditions described in US Pat. No. 4,313,124 of the invention relating to the rate of temperature rise on the heat acting surface are adopted, more excellent recording can be performed.

As the constitution of the recording head, in addition to the combination constitution of the discharge port, the liquid passage, and the electrothermal converter (the linear liquid passage or the right-angled liquid passage) as disclosed in the above-mentioned respective specifications. The present invention also includes configurations using US Pat. No. 4,558,333 and US Pat. No. 4,459,600, which disclose a configuration in which a heat acting portion is arranged in a bending region.

In addition, JP-A-59-123670 discloses a structure in which a common slit is used as a discharge portion of the electrothermal converter for a plurality of electrothermal converters, and a pressure wave of thermal energy is absorbed. The present invention is also effective as a configuration based on Japanese Patent Application Laid-Open No. 59-138461, which discloses a configuration in which an opening corresponds to a discharge portion.

Furthermore, a full line type recording head having a length corresponding to the width of the maximum recording medium which can be recorded by the recording apparatus is obtained by combining a plurality of recording heads as disclosed in the above-mentioned specification. The present invention can exert the above-mentioned effects more effectively, although it may have a configuration that satisfies the above requirement or a configuration as one recording head integrally formed.

In addition, by being mounted on the apparatus main body, it can be electrically connected to the apparatus main body and can be supplied with ink from the apparatus main body by a replaceable chip type recording head or the recording head itself. The present invention is also effective when a cartridge-type recording head provided with an ink tank is used.

Further, it is preferable to add recovery means for the recording head, preliminary auxiliary means, etc., which are provided as a configuration of the recording apparatus of the present invention, because the effects of the present invention can be further stabilized. If you list these specifically,
Capping means, cleaning means, pressurizing or sucking means for the recording head, preheating means using an electrothermal converter or another heating element or a combination thereof, and a preliminary ejection mode for performing ejection other than recording It is also effective to perform stable recording.

Further, as the recording mode of the recording apparatus, not only the mainstream color such as black but not only the recording mode, the recording head may be integrally formed or a plurality of them may be combined. The present invention is also extremely effective for a device provided with at least one of full colors by color mixing.

In the embodiments of the present invention described above, the ink is described as a liquid, but it is an ink that solidifies at room temperature or lower and softens at room temperature, or is a liquid, or the above-mentioned. In the inkjet method, the temperature of the ink itself is generally adjusted within a range of 30 ° C. or higher and 70 ° C. or lower to control the temperature of the ink so that the viscosity of the ink is within a stable ejection range. It may be in a liquid form.

In addition, the temperature rise due to the thermal energy is positively prevented by using it as the energy for changing the state of the ink from the solid state to the liquid state, or the ink is solidified in a standing state for the purpose of preventing evaporation of the ink. In some cases, such as ink that is liquefied by applying heat energy according to a recording signal and ejected as a liquid ink, or one that has already started to solidify when it reaches a recording medium. The use of an ink having a property of being liquefied only by heat energy is also applicable to the present invention. In such a case, the ink is disclosed in JP-A-54-5684.
No. 7 or JP-A-60-71260, a mode in which the porous sheet is opposed to the electrothermal converter in the state of being held as a liquid or solid in the recess or through hole of the porous sheet. May be In the present invention, the most effective one for each of the above-mentioned inks is to execute the above-mentioned film boiling method.

In addition, as a form of the recording apparatus according to the present invention, in addition to the one provided integrally or separately as an image output terminal of information processing equipment such as a word processor or a computer, a copying apparatus combined with a reader or the like, May take the form of a facsimile machine having a transmission / reception function.

[0046]

As described above, the present invention provides the upper protection.
The protective layer on the electrothermal converter side of the layer is made of SiO. ₂ As the main component,
Inkjet by doping impurities
The thermal stress durability of the recording head is improved. Also, the film formation
Since the amount of argon in the film is constant regardless of the conditions,
The film forming conditions depend on the film quality such as force and step coverage.
Can be determined, that is, compatibility with these film qualities is easy
Therefore, it is possible to provide a comprehensively reliable head.
You can Furthermore, there are no restrictions on the film forming device,
It is easy to reduce costs and increase the size.

[Brief description of drawings]

FIG. 1 is a plan view showing a main part of an embodiment of an inkjet recording head of the present invention.

FIG. 2 is a cross-sectional view of main parts taken along line XX of FIG.

FIG. 3 is a fragmentary perspective view showing the configuration of the inkjet recording head of the present embodiment.

FIG. 4 is a perspective view of an essential part showing an embodiment of the inkjet recording apparatus of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Heat-generating part 11 Substrate 12 Heat storage layer 13 Heat-generating resistor 14 Electrode 15 First protective layer 16 Second protective layer 17 Third protective layer 18 Substrate

Claims (7)

[Claims] 1. An ejection port for ejecting ink, and the ejection port
And a liquid passage communicating with the liquid passage and a heat passage provided corresponding to the liquid passage.
Energy is generated and the thermal energy causes the liquid passage
Bubbles are generated in the ink inside and the ink is discharged from the discharge port.
An electrothermal converter to be ejected and an ink for the electrothermal converter.
Ink having at least one protective layer for protection from
In the jet recording head, in the protective layer, at least the protective layer on the electrothermal converter side is protected.
The main component of the protective layer is SiO ₂ And is doped with impurities
Inkjet recording head characterized by being provided. 2. The ink jet recording head according to claim 1, wherein the impurity is phosphorus. 3. The ink jet recording head according to claim 2, which is doped with phosphorus in an amount of 0.1 to 10 atom%. 4. The ink jet recording head according to claim 1, wherein the impurity is boron. 5. The ink jet recording head according to claim 4, wherein boron is doped at 0.5 to 5 atom%. 6. The ink jet recording head according to claim 1, wherein the ink jet recording head is a full line type in which a plurality of ejection openings are provided over the entire width of the recording area of the recording medium. 7. An ink jet recording head according to claim 1, further comprising a conveying unit that conveys a recording medium, wherein ink is ejected from an ejection port of the ink jet recording head based on a recording signal. An inkjet recording apparatus for performing recording.