JPH04249158A - Ink jet recording device - Google Patents

Abstract

PURPOSE:To prevent the generation of ink mists by the bursting of bubbles, and to obtain a distinct image by devising pressure dispersion stopping power by a barrier, the spaces of energy operating sections or the width of an ink supply section. CONSTITUTION:Pressure dispersion stopping power by barriers 20 is made to differ in response to upper and lower positions in the vertical direction so as to be increased toward lower sections. Spaces among barriers 17 and each energy operating section 19 are made to differ in response to upper and lower positions in the vertical direction so as to be reduced toward lower sections. The width of ink supply paths formed by barriers is made to differ in response to upper and lower positions in the vertical direction so as to be decreased toward lower sections. Accordingly, a droplet flying effect is improved on the lower side of a head 11, in which an ink level is heightened. Flying speed and a flying droplet the same as the upper side of the lower ink level can be obtained even by the same input energy.

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 which is one of the non-impact recording methods.

0002

2. Description of the Related Art The non-impact recording method is attracting attention for use in offices, etc. because the noise generated during recording is negligible. Among these, the so-called inkjet recording method is an extremely powerful method that enables high-speed recording and can record on so-called plain paper without the need for special fixing processing, and various methods have been proposed or have already been commercialized. It is put into practical use.

[0003] In this inkjet recording method, recording is performed by ejecting small droplets of a recording liquid called ink and adhering them to a recording medium. There are several methods for controlling the flight direction of the aircraft.

[0004] The first method is disclosed in US Pat. No. 3,060, for example.
This is disclosed in the specification of No. 429. this is,
Called the Tele type method, small droplets of recording liquid are generated by electrostatic attraction, and the generated droplets are controlled by an electric field according to the recording signal to selectively adhere the droplets to the recording medium. Recording is performed using the following methods.

More specifically, an electric field is applied between a nozzle and an accelerating electrode to cause uniformly charged droplets of recording liquid to be ejected from the nozzle, and the ejected droplets can be electrically controlled in accordance with a recording signal. The droplet is caused to fly between x and y deflection electrodes configured as follows, and is selectively attached to the recording medium by changing the intensity of the electric field.

[0006] The second method is disclosed in US Pat. No. 3,596, for example.
No. 275, US Pat. No. 3,298,030, and the like. This method is called the Sweet method, and uses a continuous vibration generation method to generate recording liquid droplets with a controlled amount of charge. This is to record on a recording medium by flying the recording medium over a distance.

Specifically, a charged electrode to which a recording signal is applied is spaced a predetermined distance in front of the orifice (ejection opening) of a nozzle, which is a part of the recording head to which the piezo vibrating element is attached. By applying an electric signal of a constant frequency to the piezoelectric vibrating element, the piezoelectric vibrating element is mechanically vibrated, and a droplet of recording liquid is ejected from the orifice. At this time, charges are electrostatically induced in the ejected droplet by the charging electrode, and the droplet is charged with an amount of charge corresponding to the recording signal. When a droplet with a controlled amount of charge flies between deflection electrodes to which a constant electric field is uniformly applied, it is deflected according to the amount of charge added, and only the droplet that carries the recording signal is attached to the recording target. It will stick to the top.

[0008] The third method is disclosed in US Pat. No. 3,416, for example.
This is disclosed in the specification of No. 153. this is,
This method, called the Hertz method, is a method in which an electric field is applied between a nozzle and a ring-shaped charging electrode, and small droplets of recording liquid are generated and atomized by a continuous vibration generation method to perform recording. That is, by modulating the electric field intensity applied between the nozzle and the charged electrode in accordance with the recording signal, the atomization state of the droplets is controlled, and the gradation of the recorded image is produced.

The fourth method is disclosed in US Pat. No. 3,747, for example.
This is disclosed in the specification of No. 120. this is,
This method is called the Stemme method, and its principle is fundamentally different from the first to third methods. That is, in the first to third methods, the droplets of recording liquid ejected from the nozzle are electrically controlled while they are in flight, and the droplets carrying the recording signal are selectively applied to the recording material. In contrast, in the Stemme method, recording is performed by ejecting small droplets of recording liquid from an ejection port in response to a recording signal.

In other words, in the Stemme method, an electrical recording signal is applied to a piezo vibrating element attached to a recording head having an ejection port for ejecting a recording liquid, and this is converted into mechanical vibration of the piezo vibrating element. In response to mechanical vibration, small droplets of recording liquid are ejected from an ejection port and attached to a recording medium.

[0011] These four systems each have their own advantages, but at the same time there are also problems that need to be solved.

First, in the first to third methods, the direct energy for generating droplets of the recording liquid is electrical energy, and the deflection of the droplets is also controlled by electric field control. Therefore, although the first method is simple in structure, it requires a high voltage to generate droplets, and it is difficult to use a multi-nozzle recording head, making it unsuitable for high-speed recording.

[0013] The second method allows the recording head to have multiple nozzles and is suitable for high-speed recording. Satellite dots tend to appear on the body.

The third method allows recording with excellent gradation by atomizing small droplets of recording liquid, but on the other hand, it is difficult to control the atomization state. Further, there are drawbacks such as fogging occurring in the recorded image and difficulty in forming a recording head with multiple nozzles, making it unsuitable for high-speed recording.

On the other hand, the fourth method has relatively many advantages. First, the configuration is simple. In addition, in order to perform recording by ejecting the recording liquid from the ejection opening of the nozzle on demand, among the small droplets that are ejected and flying as in the first to third methods, small droplets that are not required for image recording are removed. No need to collect. Further, unlike the first and second methods, there is no need to use a conductive recording liquid, and there is an advantage that there is a large degree of freedom regarding the material of the recording liquid. However, on the other hand, it is difficult to make the recording head multi-nozzle because there are problems in processing the recording head and it is extremely difficult to miniaturize a piezoelectric vibrating element having a desired resonance frequency. In addition, because the mechanical energy of the mechanical vibration of the piezo vibrating element is used to eject and fly recording liquid droplets, this, combined with the difficulty of creating multiple nozzles, makes it unsuitable for high-speed recording. There is.

As described above, the conventional method has advantages and disadvantages in terms of structure, high-speed recording, multi-nozzle recording head, generation of satellite dots, fogging of recorded images, etc., and its advantages can be fully exploited. It is subject to the restriction that it can only be applied to the intended use.

[0017] Furthermore, since conventional ink jets have nozzles, they have a basic problem regarding reliability, such as clogging. However, these problems can be almost solved by a new ink jet recording system proposed by the applicant in Japanese Patent Application No. 1-225777. To summarize, this method involves inputting a drive signal according to image information to an energy acting part placed within the ink liquid surface, causing bubbles to be generated in the ink by this energy acting part, and causing the bubbles to instantly Ink is ejected from the ink liquid surface by the force exerted by the growth, and the ejected ink is attached to the recording medium.

[0018] Accordingly, first, a drive signal corresponding to image information is input to the energy application section, and when this energy application section is driven, bubbles are generated in the ink. These bubbles grow instantaneously, and due to their acting force, the ink liquid surface bulges at the portion corresponding to the energy acting portion, and the ink grows into a columnar shape. Then, when the drive of the energy application section is turned off, the grown bubbles start to contract and finally disappear without bursting. On the other hand, the ink columnar portion that has grown further moves forward, and on the base side, a constriction occurs due to bubble contraction, and is finally separated and cut from the ink liquid surface. Therefore,
The ink forms drops or columns from the portion corresponding to the energy application portion, flies toward the recording medium, and is recorded by adhering to the recording medium. In other words, a clear dot-like image can be obtained without using an orifice or a slit-like nozzle.

[0019]

However, since this proposed method has a feature that it does not have a nozzle, it has a large degree of freedom in determining the ink liquid level and is susceptible to external influences. For example, when an ink jet recording head as in the proposed example is installed vertically or tilted at a certain angle with respect to the vertical direction and used in a serial printer format,
Due to the influence of gravity, the liquid level height (thickness) from the energy acting part to the ink surface differs between the upper and lower parts of the head, and the speed and amount of flying ink droplets vary greatly depending on the height of the liquid level. This makes it impossible to obtain stable flying droplets.

[0020] This point will be explained in more detail. FIG. 11 shows an example of the proposed ink jet recording head 1. On a substrate 4 surrounded by a frame 3 so as to form an ink liquid surface 2, a plurality of heater sections 5 serving as energy application sections are installed. They are arranged in a single row array at equal intervals. Further, a plurality of barriers 6 are formed to surround each heater section 5 on all sides to secure an ink supply path 7.

FIG. 1 shows such an ink jet recording head 1.
2, when used with the array direction of the heater parts 5 being almost vertical, the height of the ink liquid level 2 is increased by the action of gravity between the heater parts on the upper side a and the heater parts on the lower side b. They will be different as shown. The inventor of the present invention conducted an experiment to investigate the relationship between the height of the liquid level and the flying droplets, and as a result, confirmed that there is a risk of deterioration of image quality.

[0022] This experimental example will be explained. First, the head shape used in the experiment is shown in FIG. 11, and the dimensions of each part are as follows:
0 μm, the arrangement density of the heater portions 5 is 180 dpi, the number of heater portions 5 is 30, the resistance value is 31Ω, and the size of the barrier 6 is 40 μm in width and 120 μm in length in the direction in which the heater portions 5 are lined up.
m, height 20 μm, width 65 μm, length 60 μm, height 20 μm perpendicular to the heater part 5 arrangement direction,
The driving voltage was 15 V, the pulse width was 5 μsec, and the ink used was BJ130 ink manufactured by Canon Corporation. Using such a head 1, the operation of continuously driving the head 100,000 times at a driving frequency of 2 kHz was repeated 10 times at intervals of 10 minutes. The liquid level height during the first drive is 20 μm,
The liquid level height was increased by about 15 μm each time, and the variation in the printing pixel diameter at that time was evaluated. IJ matte coated paper NM manufactured by Mitsubishi Paper Mills Co., Ltd. was used as the recording paper. The results are shown in Table 1.

[0023]

[Table 1]

As can be seen from Table 1, if the variation in liquid level height is 100 μm or less, approximately the same dot diameter can be obtained and the image quality will be extremely good. On the other hand, 100
If it exceeds μm, the dot diameter becomes extremely small, resulting in missing dots and poor image quality. Specifically, the state of ink flight for the first and ninth printings was observed using a strobe synchronized with the drive signal (the ink was replaced with a vehicle with almost the same physical properties as the BJ130 ink). ), the first time is shown in Figure 1.
3, and the ninth time was as shown in FIG. 14. That is, in each first flight, as shown in FIG. 13, a liquid column 9 grows from the ink liquid surface 2 due to bubbles 8 generated by heat generation due to energization of the heater section 3, and the liquid column 9 grows.
It is constricted and cut at a position below the center of the droplet 10, and the droplet 10 flies. On the other hand, each flight of the 9th time is shown in Figure 1.
4, rather than the liquid column 9 growing, the entire ink liquid level 2 rises in a conical shape, and only the center grows and becomes a droplet 10 and flies. It was observed that it returned to the liquid level. Furthermore, the speed and flight direction of the droplets 10 were also unstable.

[0025] As described above, since the flying speed of the droplets differs greatly depending on the liquid level height, when the same energy is applied to each heater section 5, the droplets fly between the upper heater section and the lower heater section. The flight speed and mass are different, leading to deterioration of image quality.

[0026]

[Means for Solving the Problems] A plurality of energy applying parts are provided within the ink liquid surface to generate bubbles that grow instantaneously in the ink, and drive signals are provided to these energy applying parts in accordance with image information. an ink jet recording head, the ink jet recording head having a signal input means for giving The barriers are arranged vertically or in an array shape with a certain inclination angle with respect to the vertical direction, and in the invention according to claim 1, the pressure dispersion prevention ability of the barrier is adjusted to the vertical position so that the pressure dispersion prevention ability increases as it goes downward. In the invention according to claim 2, the distance between the barrier and each energy acting portion is varied depending on the vertical position so that it becomes smaller as it goes downward;
In the third aspect of the invention, the width of the ink supply path formed by the barrier is varied depending on the vertical position so that the width becomes smaller as it goes downward.

[0027]

[Function] By adjusting the pressure dispersion prevention ability of the barrier, the distance between the barrier and each energy acting part, or the width of the ink supply path formed by the barrier, depending on the vertical position, the ink liquid level is higher in the lower part. Even if it is located on the side, the droplet flying efficiency is substantially increased, and a flying droplet with the same flying speed and mass as on the upper side where the ink liquid level is lower can be obtained. Therefore, it can be effectively applied to, for example, a serial printer.

[0028]

Embodiment A first embodiment of the present invention will be explained based on FIGS. 1 to 5. Ink jet recording head 11 of this embodiment
As shown in FIG. 2, the manifold 14 is formed into a trapezoidal shape and has a hollow ink supply chamber 13 connected to an ink supply pipe 12 as a base material. A heating element substrate 16 in which a slit 15 communicating with the ink supply chamber 13 is formed is fixed to the top of the manifold 14 . As shown in FIG.
5, comb-shaped barriers 17 are formed alternately on both sides, and a flow path 18 is formed between the barriers 17. These channels 18 are connected to the slit 15 in a staggered comb-like shape, contrary to the barrier 17 . Further, on the heating element substrate 16, a heater section 19, which serves as an energy application section, is formed at the innermost side for each flow path 18. Therefore, when looking at the planar arrangement of the heater portions 19, they are arranged in a staggered manner on both sides of the slit as shown in FIG. Further, a barrier 17 is placed on the heating element substrate 16 in the middle of each flow path 18.
A barrier 20 with a height equivalent to that is formed. Furthermore, a thin film-like conductive lead (signal input means) 22 that covers the circumference of the heating element substrate 16 and is held and fixed by a frame-shaped holding member 21
is provided on the manifold 14.

Here, the heater section 19 is connected to the heating element substrate 1.
A heat storage layer is formed on 6, and a heating element layer is placed on top of the control electrode.
It is formed together with a ground electrode, and the surface is further covered with a protective layer, an electrode protective layer, to avoid direct contact with the ink. Each heating element layer is electrically connected to a thin film conductive lead 22 by wire bonding via a control electrode and a ground electrode. This thin film conductive lead 22 is connected to image information signal input means (not shown).

An overview of the principle of ink flying with such a configuration will be explained. First, the ink 23 (see FIG. 4) supplied from the ink supply pipe 12 to the ink supply chamber 13 passes through the fine slit 15 due to capillary action and fills the entire comb-shaped channel 18 surrounded by the barrier 17. It will be. In this way, the entire flow path 18 is filled with ink 23 and each heater section 19 is also covered with ink 23.
In a steady state with the height of the ink liquid level adjusted, when the heater parts 19 are individually energized according to image information,
Bubbles 24 are generated in the ink liquid on the heater section 19 that generates heat. The propulsive force of the bubbles 24 causes the ink 23 to fly in a direction substantially perpendicular to the surface of the heater section 19 (substrate surface).

This will be explained in detail with reference to FIG. Note that FIG. 4 shows the heater section 19 and its surroundings in an enlarged manner. first,
FIG. 3(a) shows a steady state, in which ink 2 is distributed throughout the flow path 18.
3 is filled, and the heater section 19 is also covered with the ink 23. When the heater section 19 is heated, the heater section 19
The surface temperature of the ink increases rapidly, and the adjacent ink layer is heated until a boiling phenomenon occurs, causing micro bubbles 2 to form as shown in Figure (b).
4 are scattered. Adjacent ink layers that are rapidly heated over the entire surface of the heater section 19 are instantaneously vaporized to form a boiling film as shown in FIG. 2(c). In this state where the bubbles 24 have grown, the surface temperature will be 300 to 350°C,
It is in a so-called film boiling state. Further, the ink liquid level of the ink layer 23 above the heater section 19 rises as shown in the figure due to the driving force of bubble growth. Same figure (
d) shows a state in which the bubbles 24 have grown to the maximum, and an ink column 25 has further grown from the ink liquid surface. The time required to reach such maximum bubbles depends on the structure of the head (heat generating substrate 16), the applied pulse conditions, etc., but usually takes about 5 to 30 microseconds after the pulse is applied. At the time when the bubbles reach the maximum size, the heater section 19 is already in a non-energized state, and the surface temperature of the heater section 19 is decreasing. The timing when the bubbles 24 reach their maximum is slightly delayed from the timing of electric pulse application. Same figure (
e) shows a state in which the bubbles 24 are cooled by the ink 23 and the like and begin to contract. At the tip of the ink column 25, the ink 23 moves forward while maintaining the extruded speed, and at the rear end, the ink 23 flows back to the ink liquid surface as the bubbles 24 contract.
As shown in the figure, a constriction is created in the ink column 25. bubble 24
When the ink 23 contracts further, the ink 23 comes into contact with the surface of the heater section 19, as shown in FIG. The ink column 25 is cut off from the ink surface, becomes a droplet 26, and flies toward a recording medium (not shown) at a speed of 2 to 10 m/s. Note that the flying speed at this time depends on the structure of the head (heat generating substrate 16), ink physical properties, applied pulse conditions, etc., but when the flying speed is relatively slow, the ink 23 flies in the form of droplets, and compared to When the target is fast, the ink 23 flies in the form of an elongated column. Thereafter, as shown in FIG. 10G, the state returns to a steady state similar to that shown in FIG.

That is, according to the flying principle of this embodiment, the air bubbles 24 for flying the ink 23 do not burst but contract and shrink.
Since the bubbles disappear, generation of ink mist due to bursting of bubbles is prevented, and there is no deterioration in image quality due to ink mist. Also, unlike those that record ink in a mist form, ink 2
3 is recorded by flying it in the form of droplets or elongated columns (in any case, as a lump of ink), so it is recorded as a single dot on the recording medium, and a clear image can be obtained. .

[0033] Therefore, such an ink jet recording head 11 is used like a serial printer with the arrangement direction of the heater section 19 being vertical or slightly inclined with respect to the vertical direction. The height of the ink liquid level in each heater section 19 is different above and below the head 11. In order to compensate for this, in this embodiment, the position of the barrier 20 disposed in the flow path 18 is devised as shown in FIG. That is, as shown in FIG. 1, the barrier 20 located higher in the vertical direction a is placed farther away from the heater section 19 to have a smaller pressure dispersion prevention ability, and conversely, the barrier 20 located lower in the vertical direction b The pressure dispersion prevention ability is increased by placing it closer to the heater section 19 side.

When the barrier 20 is close to the heater section 19, its ability to prevent pressure dispersion as a barrier is strong, and the heater section 19
The surrounding pressure increases and the efficiency of droplet flight increases. Therefore, by appropriately setting the distances of these barriers 20 to each heater section 19, even if the input energy applied to each heater section 19 is the same even when the liquid level height for each heater section 19 is different, Since the flying ability on the lower side is increased, overall, the droplets 26 corresponding to each heater section 19 fly at the same flying speed and mass, resulting in good printing.

By the way, a method for forming the barrier 17 on the heating element substrate 16 for forming the flow path 18 in a state that prevents pressure dispersion in a direction substantially parallel to the ink liquid level will be explained with reference to FIG. do. In FIG. 5, only the heater section 19 is shown on the heat generating substrate 16 for the sake of simplicity. (a) on the heating element substrate 16 on which the necessary layers have been formed as described above.
As shown in the figure, a dry film photoresist 27 heated to about 80 to 105° C. is heated to a film thickness of 10 to 100° C. under pressure conditions of 0.4 to 0.5 f/min and 1 to 3 kg/cm2.
Laminate to about μm. At this time, the dry film photoresist 27 exhibits self-adhesion, and the heating element substrate 16
It is fused and fixed to the surface and will not be peeled off from the heating element substrate 16 due to the application of considerable external force thereafter.

Next, as shown in FIG. 2B, a photomask 28 having a predetermined pattern is superimposed on the dry film photoresist 27, and then exposure is performed from above the photomask 28. At this time, the installation position of the heater section 19 and the pattern of the photomask 28 are accurately aligned using a well-known method.

After the exposure process, the unexposed portions of the dry film photoresist 27 are dissolved and removed using a developer made of a predetermined organic solvent such as trichloroethane.
), the barrier 17 is formed to remain so that a flow path 18 exists corresponding to the heater section 19. The remaining exposed surface of the barrier 17 is subjected to heat curing treatment (for example, at 150 to 250°C for 30 minutes to 60 minutes) in order to improve ink resistance and to improve the adhesion between the dry film photoresist 27 and the heating element substrate 16. or ultraviolet irradiation treatment (e.g., with an ultraviolet intensity of 50 to 200 mW/cm2 or more). Both heat curing treatment and ultraviolet irradiation treatment may be performed. Further, by appropriately setting the pattern shape of the photomask 28, the barrier 20 as described above is also formed at the same time as the barrier 17.

Although a dry film type photoresist, ie, a solid photoresist, was used to form the barriers 17 and 20, the present invention is not limited to this, and for example, a liquid photosensitive composition may be used. In the case of a liquid photosensitive composition film, the squeegee method used in the production of relief images is used, i.e., a wall with a height corresponding to the desired photosensitive composition film thickness is placed around the substrate, and the excess composition is removed using a squeegee. A method to remove this can be applied. In this case, the viscosity of the photosensitive composition is 10
A range of 0 to 300 cp is preferable, and the wall height must be determined in consideration of the weight loss due to evaporation of the solvent component of the photosensitive composition.

In the case of a solid, the photosensitive composition sheet is adhered to the substrate by heat-pressing. In the present invention, it is more advantageous to use a solid film type material as described above, considering the fact that the thickness can be easily and accurately controlled in terms of handling. Specifically, such solid materials include, for example, permanent photopolymer coating RISTON (solder mask) 7.
30S (manufactured by DuPont), 740S, 730FR,
There are photosensitive resins commercially available under trade names such as 740FR and SM/. In addition, many photosensitive compositions commonly used in the field of photolithography, such as photosensitive resins and photoresists, can be used. For example, diazoresin, P-diazoquinone, photopolymerizable photopolymers using a vinyl monomer and a polymerization initiator, dimerized photopolymers using polyvinyl cinnamate, etc. and a sensitizer, orthonaphthoquinone diazide and nopolak. mixtures of polyvinyl alcohol and diazo resins, polyether type photopolymers copolymerized with 4-glycidyl ethylene oxide and penzophenone or glycidyl chalcone, N,N-dimethyl methacrylamide and acrylamide benzophenone, etc. Copolymers, unsaturated polyester photosensitive resins (for example, Asahi Kasei's APR, Teijin Co., Ltd.'s Tevista, Kansai Paint Co., Ltd.'s Sonne, etc.), unsaturated urethane oligomer photosensitive resins, and difunctional acrylic monomers. Examples include photosensitive compositions in which a polymerization initiator and polymer are mixed, dichromate-based photoresists, non-chromium-based water-soluble photoresists, polyvinyl cinnamate-based photoresists, cyclized rubber-azide-based photoresists, etc. .

Next, a second embodiment of the present invention will be explained with reference to FIG. In this embodiment, although the positions of the barriers 20 are the same, the size is made different depending on the vertical position, and the lower the barrier, the larger the barrier, thereby increasing the ability to prevent pressure dispersion. . As a result, the same effects as in the embodiment described above can be obtained.

A third embodiment of the present invention will be explained with reference to FIGS. 7 and 8. In this embodiment, the distance between the barrier 17 that surrounds each heater section 19 on three sides and each heater section 19 is set to be different so that the width is narrower in the lower part than in the upper part. be. Therefore, in this case as well, the lower the heater part 19 is, the higher the pressure around it becomes, and the droplets 26
flight efficiency increases. Therefore, each heater section 19 and barrier 1
7, the ink 23 can be ejected substantially downward even if the input energy applied to each heater part 19 is the same even when the liquid level height of the ink 23 with respect to each heater part 19 is different. Since the performance is increased, the droplets 26 corresponding to each heater section 19 fly at the same flying speed and mass as a whole, resulting in good printing.

A fourth embodiment of the present invention will be explained with reference to FIG. This embodiment is basically applied to an ink jet recording head 1 having barriers 6 as shown in FIG. 11, and the length of each barrier 6 is varied depending on the vertical position. By making the lower ones longer, each barrier 6
The width of the ink supply path 7 formed therebetween is made different. The lower the width of the ink supply path 7, the narrower it is, making it difficult for the pressure generated in the heater section 19 to escape, increasing the flying efficiency of the droplets 26. Therefore, each barrier 6
By appropriately setting the width of the ink supply path 7 between the
Even if the input energy applied to each heater section 19 is the same when the liquid level height of the ink 23 relative to each heater section 19 is different, the downward flight ability is substantially increased.
Overall, the droplets 26 corresponding to each heater section 19 fly at the same flying speed and mass, resulting in good printing.

Further, a fifth embodiment of the present invention will be explained with reference to FIG. Basically, it is similar to the above embodiment, and barriers 29 of different shapes are used, and these barriers 29
The width of the ink supply path 7 formed by the ink supply path 7 is made different depending on the vertical position.

[0044]

Effects of the Invention As described above, the present invention provides an ink jet recording head in which the energy applying portions are arranged vertically or in an array shape with a certain inclination angle with respect to the vertical direction. In this invention, the pressure dispersion prevention ability of the barrier is made to vary depending on the vertical position so that it becomes larger as it goes downward, and in the invention according to claim 2, the distance between the barrier and each energy acting part is made to become smaller as it goes downward. In the invention as claimed in claim 3, the width of the ink supply path formed by the barrier is varied depending on the vertical position so that it becomes smaller as it goes downward. Even if the droplet is on the lower side of the head where the surface is higher, the flying efficiency of the droplet will substantially increase, and even with the same input energy, the flying droplet will have the same flying speed and mass as on the upper side where the ink liquid level is lower. It is possible to obtain printing quality according to the above, and it can be effectively applied to, for example, a serial printer.

[Brief explanation of the drawing]

FIG. 1 is a schematic front view showing an enlarged main part of a first embodiment of the present invention.

FIG. 2 is an exploded perspective view showing an outline of the head structure.

FIG. 3 is an overall front view of the head.

FIG. 4 is a process diagram sequentially showing the principle of ink flying.

FIG. 5 is a cross-sectional view showing a barrier forming process.

FIG. 6 is a schematic front view showing an enlarged main part of a second embodiment of the present invention.

FIG. 7 is a schematic front view showing an enlarged main part of a third embodiment of the present invention.

8 is a cross-sectional view taken along line AA in FIG. 7. FIG.

FIG. 9 is a schematic front view showing an enlarged main part of a fourth embodiment of the present invention.

FIG. 10 is a schematic front view showing an enlarged main part of a fifth embodiment of the present invention.

FIG. 11 is a schematic plan view showing the head structure of an example proposed by the present applicant.

FIG. 12 is a sectional view taken along line BB.

FIG. 13 is a process chart sequentially showing the state of the first ink flying in an experimental example.

FIG. 14 is a process diagram sequentially showing the state of ink flying for the ninth time in an experimental example.

[Explanation of symbols]

1 Ink jet recording head 2 Ink liquid level 5 Heater part 6 Barrier 7 Ink supply path 11 Ink jet recording head 17 Barrier 19 Energy action part 20 Barrier 22 Signal input means 23 Ink 24 Air bubbles 29 Barrier

Claims (3)

[Claims] Claim 1: A plurality of energy application parts disposed within the ink liquid surface to generate bubbles that grow instantaneously in the ink, and a signal input for providing drive signals to these energy application parts according to image information. and a barrier positioned near the energy application section to prevent pressure from dispersing in a direction substantially parallel to the ink liquid level. An ink flying record characterized in that the barriers are arranged in an array at a certain inclination angle with respect to the barrier, and the pressure dispersion prevention ability of the barriers is varied depending on the vertical position so that the pressure dispersion prevention ability of the barrier increases as it goes downward. Device. 2. A plurality of energy application parts disposed within the ink liquid surface to generate bubbles that grow instantaneously in the ink, and a signal input for providing drive signals to these energy application parts according to image information. and a barrier positioned near the energy application section to prevent pressure from dispersing in a direction substantially parallel to the ink liquid level. The barriers are arranged in an array with a certain inclination angle to the barrier, and the distance between the barrier and each energy acting part is varied depending on the vertical position so that the distance between the barrier and each energy acting part becomes smaller as it goes downward. Ink flying recording device. 3. A plurality of energy application parts disposed within the ink liquid surface to generate bubbles that grow instantaneously in the ink, and a signal input for supplying drive signals to these energy application parts according to image information. and a barrier positioned near the energy application section to prevent pressure from dispersing in a direction substantially parallel to the ink liquid level. The ink supply path is arranged in an array with a certain inclination angle to the barrier, and the width of the ink supply path formed by the barrier is varied depending on the vertical position so that the width becomes smaller toward the bottom. Ink flying recording device.