JP3675207B2 - Inkjet ejection method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an inkjet head as a liquid ejection head and an inkjet ejection method used in a printer, a video printer, or the like as an output terminal for recording in a copying machine, a facsimile machine, a word processor, or a host computer. In particular, the present invention relates to an on-demand ink jet head and an ink jet discharge method using ink in a liquid state.
[0002]
In the description of the present specification, “ink” means not only a normal visible color ink but also a colorless and transparent liquid used for improving image quality by agglomerating and solidifying such ink on a recording medium. The term “image quality improving agent” is also used.
[0003]
[Prior art]
In the conventional ink jet head, ink droplets adhere to the outlet side of the ink jet ejection hole, resulting in unstable ink ejection and a problem that the ejection direction deviates greatly.
[0004]
Therefore, the surface on the outlet side of the ink jet discharge hole (hereinafter referred to as the outlet forming surface) is made to be an ink repellent surface using an ink repellent material over the entire region, or only the vicinity of the vicinity of the outlet of the ink jet discharge hole. The surface was ink repellent. These techniques are reported in detail in JP-A-5-69555, JP-A-8-318628, and the like.
[0005]
However, little consideration has been given to the utility of the ink-repellent part on the inner surface of the ink jet discharge hole.
[0006]
In JP-A-9-136423, as shown in FIG. 4, the above-mentioned water-repellent surface is formed with a thickness of 1 to 10 μm on the outlet side of the inkjet discharge hole, and this is formed on the radially inner side of the inkjet discharge hole. It is described that the protruding direction of the ink droplets from the ink jet discharge holes is stabilized by projecting the ink droplets. According to this, the meniscus surface of the ink is leveled by the presence of the water-repellent protruding portion 2, and the ejection direction is stabilized. In addition, the limiting condition that the size of the water-repellent portion 2 at the outlet of the inkjet discharge hole is smaller than the size of the hydrophilic portion 5 is set.
[0007]
However, even in the technique described in Japanese Patent Laid-Open No. 9-136423, the ink repellency portion 2 has the property of repelling ink. The action which prevents the movement of is performed. As a result, if the ink-repellent portion 2 in FIG. 4 is formed too long (thick), a phenomenon that ink jet discharge cannot be performed occurs. Further, the fact that the ink-repellent part is protruding so as to narrow the cross-sectional area of the discharge hole on the inner side in the radial direction of the discharge hole further strengthens an operation that hinders the discharge of the ink jet.
[0008]
Therefore, the length of the ink-repellent part formed on the outlet side of the ink jet discharge hole of the ink jet printer currently on the market is 0.005 μm to less than 1 μm. Further, when the diameter of the ink jet discharge hole is 1, the projecting distance inward in the radial direction is 0% to less than 5%.
[0009]
[Problems to be solved by the invention]
By the way, it goes without saying that the ink jet ejection mechanism is basically constructed in accordance with the laws of motion, that is, the application of force to an object, acceleration, and ejection. Therefore, the inkjet discharge method is a thermal energy discharge method such as a bubble jet that heats an ink liquid and causes a phase change to a gas to perform inkjet discharge, or the pressure of the liquid can be controlled using an electromechanical transducer. Even if it is a so-called piezo-type ink jet discharge method that performs ink jet discharge with a momentary increase, it operates according to the law of motion. Since the thermal energy discharge method uses the phase change of the liquid, that is, basically uses the critical boiling phenomenon of water, its discharge capacity is limited, and the generated pressure has a critical pressure around 300 ° C. It is a limit. Moreover, in order to maintain the foaming phenomenon continuously, foaming also uses the film boiling phenomenon, and the foaming time is about 10 microseconds or less. Furthermore, since the thermal energy discharge method uses only a unidirectional phenomenon of volume increase due to foaming, it is difficult to perform an operation of drawing the ink into the ink jet discharge hole and accelerating it.
[0010]
Like a pistol or a rifle, you can't load a bullet in the back of the gun barrel, add a force due to the explosive expansion of the gunpowder to accelerate it, and stabilize the trajectory while firing. is there. The reason is that ink droplets corresponding to bullets are loaded at the tip of the ink jet discharge holes corresponding to gun barrels. At the same time, since the discharge capability is low, a long acceleration space cannot be formed at the outlet of the inkjet discharge hole. That is, even if a long ink jet discharge hole having an ink repellent surface is formed, it is impossible to discharge ink due to the anti-ink force of the ink repellent surface.
[0011]
Further, since the displacement can be controlled electromechanically in the above-described piezo type ink jet system, the ink droplet, that is, the ink meniscus is once drawn slightly inside the ink ejection hole, and then accelerated and ejected therefrom. It is possible. However, since the limit of piezo displacement is extremely small, such as a displacement ratio of 3/10000 to 1/1000, a large displacement area is generated for pressure generation, and ink droplets are ejected using the tsunami effect. The amount of the ink drawn into the ink discharge hole is up to the vicinity of the boundary between the ink-philic part and the ink-repellent part of the ink jet discharge hole. Furthermore, it is just a little inside the ink against the surface tension of the ink. That is, it is about 1 μm or about 2 to 3 μm from the outlet of the ink jet discharge hole.
[0012]
In addition, in order to secure the discharge amount due to the tsunami effect of the piezo-type ink jet method, there is a problem that the degree of integration of the discharge elements becomes low. The length of the ink repellency portion is 1 μm or less. The tsunami effect is based on the principle of tsunami generation. The displacement due to the earthquake is only about 50 cm to 1 m, but it is accumulated by phenomena such as shallow water depth and wraparound of the bay, resulting in a tsunami with a height of 20 m or 40 m. In other words, even if the displacement of the piezo displacement surface is about 0.1 μm, if the displacement surface has a large area, the displacement is increased if it is accumulated in a small cross-sectional area of the ink jet discharge hole.
[0013]
In general, the piezo ink jet method requires a displacement area of about 300 times the foaming area of the thermal energy discharge method. However, due to the relationship between the common ink liquid chamber and the ink flow path, the degree of integration as an inkjet discharge unit is about 1 or 10 times. However, the ratio of 1 or 10 is very important in the function as an actual ink jet printer apparatus.
[0014]
Regardless of whether it is a piezo-type ink jet system or a thermal energy discharge system, it is impossible to use long ink-repellent ink jet discharge holes due to insufficient discharge capability at present.
[0015]
In addition, when a long ink-repellent inkjet discharge hole is formed, a phenomenon that ink droplets become spherical and stay inside the inkjet discharge hole occurs. Once spherical ink droplets stay in the ink jet ejection holes, the ink meniscus stagnates, and ink replenishment to the ink jet ejection energy generating element, that is, so-called refilling is not performed, and ink jet ejection is completely stopped. Will be. The ink refill is caused by a capillary phenomenon, which occurs when the pressure on the ink supply side and the ink receiving side is balanced or antagonistic, and stops once only one of them becomes high. If a lid made of ink droplets is formed at the tip of a thin inkjet discharge hole, ink refilling stops because of this phenomenon.
[0016]
That is, the problems of the prior art are almost summarized in the following two points.
[0017]
1) Due to the lack of ink discharge capability of the ink discharge energy generating element, it was impossible to form an ink droplet acceleration space by forming an ink jet discharge hole having a long ink-repellent surface. That is, there is a problem that an ink jet discharge method in which ink droplets are accelerated using an ink repellent ink jet discharge hole and discharged in a stable manner cannot be realized.
[0018]
2) When a long ink-repellent inkjet discharge hole is formed, ink droplets stay, and it is often impossible to refill ink.
[0019]
An object of the present invention is to provide an ink jet discharge method which can solve such conventional problems, can stabilize the pop-out direction of ink jet discharge, and can perform refill without any problem.
[0020]
[Means for Solving the Problems]
First, the solution principle of the means for solving the problem will be described. Therefore, the formation of the acceleration space in the inkjet discharge hole, which is the first problem, will be described.
[0021]
Ink jet droplets in ink jet ejection are targeted for liquid ink inside the ink ejection holes formed on the tip side of the ink jet ejection energy generating element. Further, when the ink jet droplet is about 10 picoliters or less, even the ink liquid inside the ink ejection hole is almost the target of the ink liquid at the tip, that is, at the outlet.
[0022]
However, the ink jet ejection operation is performed at a portion away from the tip. For example, there is one that employs a thermal energy ejection method that utilizes a thermal foaming phenomenon by an inkjet ejection energy generating element at a site that is 50 μm to 70 μm away from the tip of the ink. In addition, there is a so-called edge shooter system that employs a thermal energy discharge system that utilizes a thermal foaming phenomenon at a site about 80 μm to 250 μm away from the tip. Some adopt a thermal energy discharge method utilizing the thermal foaming phenomenon at a site 20 to 30 μm away from the tip. Further, there is a printer that employs a piezo-type ink jet system that uses a piezo displacement of an ink liquid chamber at a position about l200 μm away from the tip.
[0023]
In this way, with a pistol or rifle, the ink liquid located at the tip of the inkjet discharge hole, which is a bullet, is instantaneously changed and the displacement is propagated to the ink liquid at the tip of the inkjet discharge hole for acceleration. It is a mechanism for discharging. Therefore, most of the ink jet discharge is performed at a portion where the acceleration is output from the outlet of the ink jet discharge hole. In other words, it is an extra-fire launch called ballistics, and the trajectory becomes unstable. Therefore, the shape of the ink jet discharge hole and its homogeneity are very important. As described above, since the stability of the ejection trajectory of the ink droplet is important, the piezo method adopts a striking method as disclosed in Japanese Patent Laid-Open No. 60-2372, and realizes a slight acceleration space. doing. Due to the surface tension of the ink liquid, the displacement of the ink droplet is stabilized at a right angle to the exit surface, so this stable region is used as an acceleration space. However, since the acceleration space is still insufficient, the piezo head of company E has a water repellent layer with a thickness of about 1 μm on the exit forming surface to form a 1 μm acceleration space.
[0024]
However, when the frequency of ejection becomes higher or the level of ejection capability is not achieved, if this water repellency, that is, the distance between the sparse or ink-repellent portions is increased, inkjet ejection cannot be performed satisfactorily. In fact, when the discharge frequency exceeds 1 OKHz, the distance of the ink repellency is limited to about 1 μm. However, an acceleration space of about 1 μm is insufficient because of the trajectory stability of the ink jet droplet trajectory. At least 5 μm or more is required. The reason is that if the diameter of the ink jet discharge hole is 20 μm, the ink liquid column having a height of 10 μm has an ink amount of about 3.1 picoliters, and at least half of the amount needs to stabilize the orbital direction. Because.
[0025]
If possible, the acceleration distance is preferably 10 μm or 20 μm. However, if this distance of ink repellency becomes long, it becomes a hindrance to ink jet ejection, and ink is not ejected.
[0026]
Therefore, as a result of diligent investigations, the outlet side portion is ink repellant for a predetermined distance when ink is loaded inside the ink jet discharge hole before being discharged, and the ink discharge operation state is the parent in the ink jet discharge operation state. We realized a method to stabilize the ejection trajectory of ink droplets well by means to change to ink properties. In this way, when the ink droplets to be bullets are loaded into the ink jet discharge holes, an ink repellent portion can be formed at the tip of the ink droplets, that is, an acceleration space can be formed. Since it becomes ink-philic at the time of ejection, it becomes possible to perform ink-jet ejection satisfactorily. In other words, it is a means for instantaneously switching between ink repellency and ink affinity by signal control.
[0027]
As the specific means, a means for forming the ink jet discharge hole portion with a material that reversibly changes to ink repellency and ink repellency by light irradiation is used.
[0028]
Furthermore, this material is made to exhibit a reversible reaction between ink repellency and super-ink affinity by photocatalytic reaction or photochromic reaction so that ink can be discharged and accelerated satisfactorily.
[0029]
In this way, the first problem is solved.
[0030]
Next, the second problem is that ink droplets stay inside the ink-repellent inkjet discharge hole, and the surface of the inkjet discharge hole is formed with a material that generates an interfacial tension much higher than the surface tension of the ink. I found out that I should do it. In other words, the ink repellent portion is a surface having an interfacial repulsive force of which the interfacial tension with the ink is almost zero or rather negative. Thus, it has been found that the ink repellency portion may be a surface having a high interfacial tension with ink. As described above, the portion corresponding to the acceleration space on the exit forming surface is a surface that reversibly changes to ink repellency and ink affinity, so if this ink affinity portion is made super ink affinity, It ’s good. As described above, since super-ink affinity can be obtained by a photocatalytic reaction or a photochromic reaction, it is possible to prevent ink droplets from staying.
[0031]
By taking such measures, the second problem is solved.
[0032]
Therefore, in the inkjet discharge method of the present invention that solves the above-described problem, at least a part of the hole surface arranged at or near the outlet of the inkjet discharge hole for discharging ink has a phobic property due to light sparseness. Inkjet ejection part formed of a material that changes to ink properties And an energy generating element that generates energy for discharging ink, Before using an inkjet head with Record An ink jet discharge method for discharging ink from an outlet of an ink jet discharge hole,
In a state where the material that changes from ink repellency to ink repellency in response to light irradiation exhibits ink repellency, an ink meniscus is positioned on the inner side from the outlet of the inkjet discharge hole, and an inkjet acceleration space is secured. Further, the ink meniscus is changed in the acceleration space by irradiating light and changing the material that changes from sparse ink to ink affinity according to the light irradiation to ink affinity. Accelerate while moving, said Depending on the energy generated by the energy generating element Ink is ejected.
[0033]
Here, the light may be emitted from a light source that can control transmission and stoppage.
[0035]
Furthermore, it is preferable that the surface on which the outlet of the inkjet discharge hole is formed is an ink-phobic surface.
[0036]
Further, the hole surface of the inkjet discharge hole is directed from the outlet toward the back, and a portion of the ink-phobic material, Depending on light irradiation Sparse ink From It is preferable to form in order of the part of the material which changes to ink affinity, and the part of the ink affinity material.
[0037]
Also, the above Depending on light irradiation Sparse ink From The material that changes to ink affinity is preferably reversibly changed to ink phobic or ink affinity by a photocatalytic reaction or a photochromic reaction.
[0038]
Further, the material exhibiting the photochromic reaction is a 2,3 epoxyindanone derivative, a mixture of the 2,3 epoxyindanone derivative and an organic substance or an inorganic substance, a spirobenzopyran derivative, the spirobenzopyran derivative and an organic substance or an inorganic substance, Preferably, it is one selected from the group consisting of:
[0039]
Further, the material exhibiting the photocatalytic reaction was selected from the group consisting of titanium oxide, zinc oxide, tungsten oxide, iron oxide, cadmium sulfide, each inorganic compound, and each inorganic compound and organic substance or a mixture of inorganic substances. One is preferable.
[0045]
The light Irradiation Depending on sparse ink From It is preferable that the material reversibly changing to the ink affinity is made to be an ink-phobic state and the ink is refilled to the ink jet discharge section.
[0046]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described in detail based on examples described in the accompanying drawings. Throughout the description and the drawings, the same numbers are used for the same functional parts.
[0047]
FIG. 1 is a schematic cross-sectional view of a preferred embodiment of the present invention. An ink-repellent layer 2 having a length (thickness) of 0.5 μm is disposed at the exit 1 portion of the ink jet discharge hole 3, and then a layer having a length of 12 μm that changes to ink repellency or ink affinity. 4 (hereinafter referred to as “transformation layer” or “transformation part”), a component part 6 of the ink jet discharge hole 3 made of the ink-philic layer 5 is disposed on the side.
[0048]
An inkjet discharge energy generating element 7 for inkjet discharge is disposed in the innermost part of the inkjet discharge hole 3. The ink 8 forms an interface with the external air layer 10 by the ink meniscus 9, and when the transformation layer 4 is sparse or ink repellent, the ink meniscus 9 is formed between the transformation layer 4 and the ink-philic layer 5. It is formed at the boundary position.
[0049]
When the transformation layer 4 is ink-philic or super-ink affinity, the ink meniscus 9 exists at the boundary between the ink-repellent layer 2 and the transformation layer 4 in the state shown in FIG.
[0050]
By controlling the position of the ink meniscus 9 in this way, it is possible to form a barrel as in the case of a rifle or pistol, and it is possible to form an acceleration space for the ink droplets 11. Therefore, in this case, the length of the acceleration space is 12 μm.
[0051]
However, 0.5 μm or 12 μm shown here is merely a numerical value for ease of understanding and is not limited in any way.
[0052]
Next, as shown in FIG. 3, in order to maintain ink repellency at the time of refilling as ink loading, as shown in FIG. 3, light 200 is blocked or not irradiated, and ink jet discharge is performed. At the moment when the energy generating element 7 operates, or at the time before and after the operation, the transformation layer 4 is transformed into an ink-philic or super-ink-philic state by irradiating the transformation layer 4 with light, thereby improving ink jet discharge. It is set to be made to perform. By doing so, the ink 8 moves in the transformation layer 4 almost simultaneously with the ink jet discharge operation, the discharge trajectory is defined, and the discharge is stabilized.
[0053]
Thereafter, when the ejection is completed, the irradiation of the light 200 is stopped, and the transformation layer 4 is transformed into ink repellency, whereby the position of the ink meniscus 9 at the time of refilling is the ink-philic layer 5 shown in FIG. And a boundary surface position between the transformation layer 4. By repeating this in a cycle, good ink jet discharge with an acceleration space can be realized.
[0054]
The ink-repellent layer 2 is composed of a fluorine-based water-repellent layer. Specifically, the ink-repellent layer 2 is a mixture of an organic resin or an inorganic substance with polytetrafluoroethylene (trade name: Teflon), carbon fluoride, fluorocarbon, or the like. It is composed of a mixture of zirconium fluoride with an organic resin or an inorganic substance.
[0055]
The transformation layer 4 is composed of a material exhibiting a photocatalytic reaction such as titanium oxide, zinc oxide, or tungsten oxide, or a mixture thereof with an organic or inorganic material. Alternatively, it is composed of a material such as an epoxyindanone derivative or a spirobenzopyran derivative exhibiting a photochromic reaction, or a mixture thereof with an organic or inorganic substance.
[0056]
【Example】
Examples of the present invention will be described below.
[0057]
The ink jet head 100 having the cross-sectional configuration shown in FIGS. 1 and 2 was formed as follows.
[0058]
An ink-repellent layer 2 having a depth of 0.5 μm is formed at the outlet 1 of the ink jet discharge hole 3, and then a transformation layer 4 having a depth of 12 μm and changing to an ink-repellent or ink-philic property is further provided thereunder. The ink-philic layer 5 is disposed on the surface.
[0059]
In the manufacturing method of this configuration, an uncured silicon resin or a precursor thereof mixed with titanium oxide (anatase type) having a particle size of 0.0 lμm is coated on the polyimide layer 5 by about 15 μm by a coating method. Applied.
[0060]
Thereafter, it was held at a temperature of 80 ° C. for 1 hour and cured and bonded by condensation polymerization. By polycondensation, the layer 4 was slightly thinned to form a layer 4 of about 12 to 13 μm. On top of this, a fluorine-based ink repellent material having a phenyl group was spin-coated to produce the ink repellent layer 2.
[0061]
Next, holes having a diameter of 30 μm were formed in the polyimide layer 5 (which becomes a part of the discharge holes) at a pitch of about 80 μm by an excimer ultraviolet laser. Separately from this operation, an ink flow path 102 was formed by the laser so as to communicate perpendicularly to the hole as shown in FIGS. The depth of the flow path can be set almost arbitrarily by adjusting the irradiation time of the laser.
[0062]
Since the transformation layer 4 does not have a large ultraviolet absorption range, even if the polyimide layer is removed by ablation, the transformation layer 4 is not deformed to the extent that a hole is opened, and remains in a substantially planar state.
[0063]
Next, the discharge hole 3 having a diameter of 20 μm was formed in the ink repellent layer 2 and the transformation layer 4 by a carbon dioxide gas laser so as to be positioned at the center of the hole having a diameter of 30 μm. Since the carbon dioxide laser instantaneously melts the ink-repellent layer 2 and the transformation layer 4 with heat and opens holes, by blowing a mixed gas of nitrogen helium at 8 atm as an assist gas in order to blow off the waste. went. As a result, an ink jet discharge hole 3 having a configuration as shown in FIGS. A YAG laser may be used instead of the carbon dioxide laser.
[0064]
An adhesive layer to be removed by an excimer laser is formed in advance on one side of the polyimide layer 5, and an inkjet discharge energy generating element substrate 10 l on which an inkjet discharge energy generating element 7 is formed on the upper surface through this layer. And joined. An electrothermal conversion element was used as the inkjet discharge energy generating element 7. The polyimide layer 5 (103) is formed with the above-described ink flow path 102 shown in FIGS. 1 and 2, and one end thereof communicates with the ink supply path 104. In this way, the inkjet head 100 was constructed.
[0065]
When ink 8 was supplied to the inkjet head 100 in this state in a dark room, the ink 8 formed an interface with the external air layer 10 by the ink meniscus 9. The meniscus 9 was formed as shown in FIG. 1 at the boundary between the transformation layer 4 and the polyimide layer 5 which is an ink-philic layer. It was measured with a Keyence Corporation laser position displacement meter. The operating wavelength of the laser position displacement meter used here is in the near infrared region of 950 nm.
[0066]
Next, when the inkjet head 100 is irradiated with ultraviolet rays of about 300 nm, the transformation layer 4 becomes ink-philic or super-ink affinity, and the ink meniscus 9 is formed between the ink-repellent layer 2 and the transformation layer 4. It was confirmed that the boundary exists in the state as shown in FIG.
[0067]
Thus, by controlling the position of the ink meniscus 9, it is possible to form a gun barrel as a rifle or a pistol, and to confirm that an acceleration space for the ink droplet 11 can be formed. It was.
[0068]
Therefore, in this case, the length of the acceleration space corresponds to the thickness of the transformation layer 4 and is about 12 μm. In addition, although it repeats, 0.5 micrometer shown here or l2 micrometer is a numerical value of an example, and is not limited to this at all.
[0069]
Next, as shown in FIG. 3, in order to maintain ink repellency, as shown in FIG. 3, in order to maintain the ink repellency, the operation is performed in a dark state where the light 200 is blocked or not irradiated. The transformation layer 4 was irradiated with light 200 2 microseconds before the discharge energy generating element 7 was turned on. When the transformation layer 4 is transformed into an ink-philic or super-ink-philic state, the pore surface formed by the transformation layer 4 is reduced in surface energy at a speed of about 1 μm / microsecond, as shown in FIG. Thus, it was confirmed that the position of the meniscus 9 of the ink 8 moves. FIG. 3 shows how the meniscus 9 moves with and without ejection.
[0070]
As a result, along with the movement of the meniscus 9 of the ink 8, inkjet discharge is performed by the inkjet discharge energy generating element 7, and the inkjet liquid is accelerated while being accelerated in the hole surface of the discharge hole 3 formed by the transformation layer 4. The droplet l1 is ejected. Due to the movement in the acceleration space, the moving direction vector of the droplet 11 is determined, and the level of “smoothness” due to the conventional inkjet discharge is reduced.
[0071]
Irradiation of the light 200 may be stopped once the ink jet droplet 11 exits from the ejection hole 3, and therefore the time required for ink jet ejection is approximately 10 microseconds or less because the irradiation time is about 10 microseconds or less. Set to.
[0072]
When the irradiation of the light 200 is stopped after completion of the ejection, the transformation layer 4 changes to ink repellency, and the position of the ink meniscus 9 in the refill is the boundary surface between the ink-philic layer 5 and the transformation layer 4 shown in FIG. Defined in position. By repeating these in a cyclic manner, good ink jet discharge with an acceleration space has been realized.
[0073]
The ink repellent layer 2 is composed of a fluorine-based water repellent layer, specifically, Asahi Kasei water repellent CTX-1500. In addition, it may be composed of a mixture of an organic resin or inorganic substance with polytetrafluoroethylene (trade name: Teflon), or a mixture of an organic resin or inorganic substance with carbon fluoride.
[0074]
【The invention's effect】
As described above, according to the present invention, since the position of the ink meniscus can be controlled by light irradiation, an ink acceleration space can be formed. With this effect, the movement direction vector of the ink droplet is made constant by the accelerated movement of the inkjet droplet in the acceleration space, and the “blurring” in the case of inkjet discharge is eliminated.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view showing an ink jet head according to a preferred embodiment of the present invention, showing the position of a meniscus when light is not irradiated.
FIG. 2 is a cross-sectional view of the embodiment of FIG. 1 when the meniscus position changes when light is irradiated.
FIG. 3 is a timing chart showing an example of control of the inkjet discharge method of the present invention.
FIG. 4 is a schematic sectional view of a conventional inkjet head.
[Explanation of symbols]
l Inkjet ejection hole outlet
2 Repellent (sparse) ink layer
3 Inkjet ejection holes
4 Transformation layer
5 Ink affinity layer
6 Inkjet ejection hole component
7 Inkjet discharge energy generating element
8 Ink
9 Meniscus
10 atmosphere layer
1l inkjet droplet
100 inkjet head
101 Inkjet discharge energy generating element substrate
102 Ink channel
103 Polyimide layer
104 Ink supply path
200 light

Claims (8)

An inkjet discharge section in which at least a part of a hole surface disposed at or near an outlet of an inkjet discharge hole for discharging ink is formed of a material that changes from sparse ink property to ink affinity according to light irradiation ; , an ink jet ejection method to eject ink from the outlet of the previous SL inkjet discharge holes using an inkjet head comprising an energy generating element for generating energy for discharging ink,
After the ink meniscus is positioned on the inner side from the outlet of the inkjet discharge hole in a state in which the material that changes from ink repellency to ink affinity in response to the light irradiation exhibits ink repellency, after securing an acceleration space of the inkjet, Further, the ink meniscus is changed in the acceleration space by irradiating light and changing the material that changes from sparse ink to ink affinity according to the light irradiation to ink affinity. An inkjet ejection method, wherein the ink is ejected by energy generated by the energy generation element while being accelerated while being moved.   2. The inkjet discharge method according to claim 1, wherein the light is emitted from a light source that can control transmission and stop.   The inkjet discharge method according to claim 2, wherein the surface on which the outlet of the inkjet discharge hole is formed is an ink-phobic surface.   The surface of the ink jet discharge hole is formed in the order of the ink-phobic material part, the ink-phobic material part, the material part changing from the sparse ink to the ink-philicity part, and the ink-philic material part in order. The inkjet discharge method according to any one of claims 1 to 3.   5. The material that changes from an ink phobic property to an ink repellency in response to light irradiation, reversibly changes to an ink phobic property or an ink philic property by a photocatalytic reaction or a photochromic reaction. The inkjet discharge method as described.   The material showing the photochromic reaction is a 2,3 epoxyindanone derivative, a mixture of the 2,3 epoxyindanone derivative and an organic or inorganic substance, a spirobenzopyran derivative, or a mixture of the spirobenzopyran derivative and an organic or inorganic substance. 6. The inkjet discharge method according to claim 5, wherein the inkjet discharge method is one selected from the group consisting of bodies.   The material exhibiting the photocatalytic reaction is one selected from the group consisting of an inorganic compound of titanium oxide, zinc oxide, tungsten oxide, iron oxide, and cadmium sulfide, and a mixture of the inorganic compound and an organic substance or an inorganic substance. The inkjet discharge method according to claim 6, wherein:   2. The inkjet discharge method according to claim 1, wherein a material that reversibly changes from sparse ink to ink affinity in response to the irradiation of light is set to an ink phobic state and ink is refilled to the inkjet discharge unit. 3. .

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