JPS634955A - Liquid jet recording head - Google Patents

Abstract

PURPOSE:To record a high grade image having no density irregularity by uniformizing the width of the heat generating resistor layer of a heater, by providing the same layer as the heat generating resistor layer or a layer having an etching ratio equal to that of the heat generating resistor on both sides of each of a plurality of electrothermal converter elements formed in an etching process. CONSTITUTION:Each of electrothermal converters (hereinafter referred to as heaters) subjected to liquid injection of a group 200 of heaters has a heat generating resistor layer 201 and an electrode layer 203. Groups 202 of electrothermal converters (hereinafter referred to as dummy heaters) not concerned in liquid injection arranged on both sides of the group 201 of heaters and subjected to the areal uniformization of the heat generating resistor layers 201A of the heaters can be provided in sufficient numbers (e.g., ten or more) to such a degree that no effect of the edge effect of etching is exerted on the group 201 of the heaters according to the same process as the heaters. That is, the heaters are formed in numbers more than necessary numbers in the recording of an image and the heaters except a proper number of the heaters present on both end parts thereof are used as actual heaters and, by this method, a uniform head having no flaw can be provided.

Description

Detailed Description of the Invention] (Hereinafter in the margin) 3. Detailed Description of the Invention [Field of Industrial Application] The present invention is a method of ejecting a recording liquid (ink) as flying droplets and using the droplets to spray a recording medium onto a recording medium. The present invention relates to a liquid jet recording head disposed in a liquid jet recording apparatus that performs recording, and particularly to a liquid jet recording head that jets liquid in response to the action of thermal energy.

[Prior art 1 The liquid jet recording method has extremely excellent features in that the noise generated during recording is extremely small to the extent that it can be ignored, and high-speed recording is possible. is being actively researched and developed.

Among these, there is an injection method in which liquid is discharged by applying thermal energy to the liquid, in other words, the liquid affected by thermal energy undergoes a state change accompanied by a sudden increase in volume.
A recording method in which liquid is ejected from an ejection port (orifice) at the tip of the recording head using the acting force generated due to the state change is a recording head with aligned orifices, so-called multi-orifice recording. It is attracting attention because the head can be easily implemented and high-resolution and high-quality images can be obtained at high speed.

The recording head of a liquid jet recording device that applies the refusal method is
A liquid discharger having a liquid flow path that includes an orifice provided for discharging liquid, and a heat acting part that communicates with the orifice and applies thermal energy to the liquid in order to discharge the liquid. and an electrothermal converter as a means for generating thermal energy. This electrothermal converter is made up of a pair of electrodes and a heat generating resistor layer connected between these electrodes and having a heat generating region (heat generating section). That is, the thermal energy generated by this electrothermal converter acts on the liquid to generate bubbles, causing a rapid change in state due to expansion and contraction of the volume.

[Problems to be Solved by the Invention] Here, since the volume of this bubble has a correlation with the droplet diameter, in order to perform good printing, it is necessary to It is required that various physical properties be uniform.

However, the heating resistor layer is formed into a desired shape by an etching process, but during this etching process, the circulation of the etching solution is better at both ends of the heating resistor group than in the center (hereinafter referred to as the end effect of etching). , etching progresses easily (the etching rate is high), and in conventional recording heads, the resistive layer is formed thin especially in the width direction.

FIG. 7 shows the width distribution of the heat generating resistor layer in a conventional recording head, and it can be seen that the width at both ends is clearly narrower than at the center.

As a result, in the conventional recording head, there is a problem in that the recording density becomes uneven in the arrangement direction of the heating resistor layer, and the print becomes thinner from the center toward both ends.

Means for Solving Problem E] The present invention solves these conventional problems, eliminates the unevenness caused by the non-uniform width of the heating resistor layer of the electrothermal converter, and thereby produces high-quality images. An object of the present invention is to provide a liquid jet recording head capable of recording.

Therefore, in the present invention, a plurality of ejection ports are provided for ejecting liquid to form flying droplets, and a plurality of ejection ports are provided corresponding to each of the plurality of ejection ports and used for forming flying droplets. a plurality of electrothermal transducers formed by an etching process, and a layer provided on both sides of the plurality of electrothermal transducers that is the same as the heat generating resistor layer. Alternatively, a layer having an etching rate equivalent to that of the heating resistance layer is provided.

[Function 1] That is, according to the present invention, when forming the heating resistance layer of the electrothermal transducer for forming droplets, the effect of the circulation of the etching solution that may occur on both sides of the layer is reduced by the layers provided on both sides. Since it does not reach the heat generating resistance layer involved in droplet formation, the width of the heat generating portion is made uniform.

[Example 1 Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 shows an example of the configuration of a liquid jet recording head according to the present invention. Here, 200 is a group of electrothermal transducers (hereinafter referred to as heaters) used for liquid ejection, and each heater has a heat generating resistance layer 201 and an electrode layer 203. -2
Reference numeral 02 denotes a group of electrothermal transducers (hereinafter referred to as dummy heaters) that are disposed on both sides of the group of heaters 201 and are not involved in liquid jetting and serve to equalize the area of the heating resistance layer 201A of the heater. The number of dummy heaters is sufficient (for example, one
(0 or more) can be provided in the same process as the heater.

In other words, in this example, more heaters are created than necessary for image recording, and only the appropriate number of heaters at both ends are used as the actual heaters. This means that a uniform, defect-free head can be provided without any change.

Note that the dummy heater may have exactly the same configuration as the heater, but since it is not used for droplet formation, there is no need to generate heat in the gap between the negative pair of electrodes. Therefore, there is no need to provide wiring with the drive signal supply source, and it is sufficient to simply provide it on the substrate.

Such a liquid jet recording head can be produced by the following procedure.

First, a 5 μm thick 5i film was applied to the surface of the St wafer by thermal oxidation.
02 film is formed. Furthermore, HfB2 was sputtered to a thickness of 1,500 mm as a heating resistance layer using a sputtering method.
Subsequently, 5,000 layers of Aj2 are deposited by electron beam evaporation.

Next, a pattern is formed by a photolithography process so that desired shapes of the heating element and electrodes are obtained.

Next, the 5i02 layer was formed by high-rate sputtering.
．． Deposit 5 μm.

Thereafter, as a resist for Ta lift-off, a polyimide film such as PIQ manufactured by Hitachi Chemical is patterned to a thickness of 3 μm, and a Ta film of 1.0 μm is formed by DC sputtering. After this Ta film is formed, the PIQ film is peeled off to obtain a desired Ta film pattern, and the substrate fabrication is completed.

Finally, the grooved glass plate for forming the liquid flow path, the heat acting part, and the orifice is aligned so that the groove is placed in an appropriate positional relationship with the heat generating part formed on the substrate. Glue.

Note that if the shape of the dummy heater is different from that of the heaters belonging to the group 200 as shown in the figure, the dummy heaters can be easily distinguished from the heaters, and the heater wiring can be easily and reliably performed.

FIG. 2 shows another example of the configuration of the liquid jet recording head according to the present invention. In this example, the heater 2 for liquid injection is
00, a rectangular resistance layer 301 having a width sufficient to prevent the width of the heater from becoming narrow is provided as a pseudo heating resistance layer.

The recording head according to this example can also be manufactured in substantially the same manner as the first example. Note that also in this embodiment, since the resistance layer 301 is not related to liquid ejection, it is not necessarily necessary to wire these resistance layers.

FIG. 3 shows an embodiment in which a resistance layer 401 having different dimensions from the rectangular resistance layer 301 in FIG. 2 is provided.

4 and 5 show resistance layers 501 and 60, respectively, which are obtained by subdividing the resistance layer of the embodiment shown in FIG. 2 or 3.
In these Examples, HfB2 was easily dissolved due to the increase in the boundary portion of the resistance layer.

The liquid jet recording head configured as in these embodiments is
Since the heater for liquid injection is manufactured with heating resistance layers not related to liquid injection provided at both ends, as shown in FIG.
The width of the resistance layer for liquid jetting became almost uniform. Therefore, a high quality image with no unevenness can be obtained.

Further, since the heat generating resistor layer not related to liquid ejection is formed in the same manufacturing process as the heater for liquid ejection by simply adding a pattern, the manufacturing process of the recording head does not become complicated.

In the above-described embodiment, the layers provided on both sides of the heater 200 are made of the same material as the heat-generating resistor layer 201, that is, they are formed as a pseudo heat-generating resistor layer. Of course, it may also be formed from a material that has the following properties.

[Effects of the Invention] As explained above, according to the present invention, the width of the heating resistor layer of the heater related to liquid jetting is made uniform, and a liquid jet recording head capable of recording high-quality images without density unevenness is provided. realizable.

[Brief explanation of the drawing]

FIG. 1 is a schematic plan view showing one configuration example of the liquid jet recording head according to the present invention, and FIGS. 2 to 5 are schematic plan views showing other word configuration examples of the liquid jet recording head according to the present invention. Figures 6 and 7
The figures are diagrams showing the distribution of the width of the heating resistor layer of the present invention and the conventional head, respectively. 200...Electrothermal converter (heater) for liquid injection, 20
DESCRIPTION OF SYMBOLS 1... Heating resistance layer, 202... Electrothermal converter for uniform heating area (dummy heater), 301.401, 501, 601... Pseudo heating resistance layer. Figure 1 Figure 2

Claims (1)

[Claims] A plurality of ejection ports provided to eject liquid to form flying droplets, and thermal energy provided corresponding to each of the plurality of ejection ports and used to form the flying droplets. a plurality of electrothermal conversion elements formed by an etching process, and a layer that is the same as the heating resistance layer or provided on both sides of the plurality of electrothermal conversion elements, A liquid jet recording head comprising a layer having an etching rate equivalent to that of a resistive layer.