Patent Application
20210362507
The present invention relates to an ejection apparatus that ejects a liquid or liquid-like ejection material and to an imprinting apparatus including the ejection apparatus.
As for an ejection apparatus that ejects a liquid or liquid-like ejection material stored in a storing container from an ejection head, PTL 1 describes a configuration using a storing container partitioned into two storing portions by a flexible member. One of the storing portions in the storing container stores the ejection material, while the other storing portion stores a liquid, and the internal pressure of the other storing portion is controlled to indirectly adjust the internal pressure of the one storing portion. Inside such a storing container, the internal pressures of the one storing portion and the other storing portion are equalized to each other. For this reason, even if the flexible member is damaged, the internal pressures will remain unchanged. This makes it difficult to detect the occurrence of the damage.
To address this, PTL 2 describes a configuration in which the other storing portion stores a liquid that differs in physical property from the ejection material and does not get mixed with the ejection material, and which detects damage of the flexible member by detecting a change in physical property of the liquid that occurs when the ejection material enters the other storing portion.
However, according to the configuration of PTL 1, the ejection material and the liquid, stored in the respective storing portions, are limited to ejection materials and liquids having detectable different physical properties. Also, once the flexible member is damaged, the ejection material and the liquid start contacting each other through the damaged spot, but it will take time before the change in physical property of the liquid becomes detectable after the start of the contact. For this reason, the damage of the flexible member cannot be detected immediately after its occurrence. Further, even without being mixed with the liquid, a certain kind of ejection material may be deteriorated in quality by simply contacting the liquid. In that case, if the ejection material having contacted the liquid is ejected, products with deteriorated quality will keep being manufactured as long as this ejection material is ejected from the ejection head.
In addition, physical properties of the ejection material inside its storing portion may possibly change even if the storing portion is damaged at a spot other than the flexible member.
The present invention provides an ejection-material ejection apparatus and an imprinting apparatus capable of quickly detecting damage of a flexible membrane and avoiding contact between an ejection material and a liquid even if part of the flexible membrane is damaged.
An ejection-material ejection apparatus of the present invention comprises:
According to the present invention, the flexible membrane has a two-layer structure with the first film and the second film. Thus, it is possible to avoid contact between the ejection material and the operating liquid even if one of the first film and the second film is damaged. Moreover, with the inter-film space between the first film and the second film, it is possible to quickly detect damage of at least one of the first film and the second film by detecting a change in state of the inter-film space.
Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings.
Preferred embodiments of the present invention will now be described based on the accompanying drawings.
(Configuration of Ejection-Material Ejection Apparatus)
The ejection apparatus in this embodiment includes a main tank 34 communicating with the atmosphere and holding an operating liquid 35 therein, a sub tank 26 communicating with the atmosphere, being capable of communicating with the main tank 34, and holding an operating liquid 35 therein, and an ejection-material storing unit 100 communicating with the sub tank 26. The ejection-material storing unit 100 includes a storing container 13 storing an ejection material and an ejection head 14 mounted to the storing container 13. Note that the storing container 13 and the ejection head 14 may be configured as separate components or configured integrally with each other. The storing container 13 may be of a cartridge type. The ejection head 14 can eject the ejection material from ejection ports 15 opening at the outer surface (ejection surface) of the ejection head. The ejection ports 15 in this embodiment are arranged on the ejection surface of the ejection head 14 at a density of 500 to 1000 ports per inch.
As illustrated in
(Ejection Material)
The ejection material is a material that does not have a fixed shape but exhibits fluidity unlike solids and does not undergo significant volume change unlike gases when it is inside the storing container 13 and also when it is ejected from the ejection head 14, and is a liquid or liquid-like material. The ejection material may be a material such as a material in past form or a polymetric material. Ink is usable as the ejection material in this embodiment. Non-limiting examples of the ink include various inks such as ink for printing images, electrically conductive ink for fabricating electric circuits, and UV-curable ink. Examples of the electrically conductive ink include inks containing metal particles, in particular, metal nano-inks containing metal nano-particles of several to several tens of nanometers dispersed in a liquid, e.g. silver nano-ink. For fabrication processes of semiconductor devices and the like, there is a so-called imprinting technique, in which a mold with a pattern formed thereon is brought into contact with an imprint material on a substrate to thereby transfer the shape of the mold into the imprint material and form the pattern therein. A resist such as photocurable resin or thermosetting resin is used as the imprint material. Other examples of the ejection material include imprint materials as above as well.
(Operating Liquid)
The operating liquid is an incompressible material whose density (volume) change upon receipt of external temperature and pressure is negligibly small as compared to that of gases. Thus, the volume of the operating liquid hardly changes even when the temperature or pressure of the air around the ejection apparatus changes. A material selected from among liquids like water and materials in gel form is usable as the operating liquid, for example. Usually, the difference between the density of the ejection material and the density of the operating liquid is smaller than the difference between the density of the ejection material and the density of gas.
In the case of using the ejection apparatus according to the present invention as an ink ejection apparatus of a printing apparatus, for example, ink is used as the ejection material as a matter of course. On the other hand, ink, which is costly, does not need to be used as the operating liquid but water, which has a close relative density to ink, can be used instead. More specifically, water in which an additive with a preservative function is added to prevent decomposition and growth of bacteria in water can be used as the operating liquid.
(Configuration of Control System of Ejection Apparatus)
By following a control program stored in an ROM 204, a CPU 202 drives the conveyance unit 62 by means of a conveyance drive unit 210 and drives the ejection head 14 by means of an ejection drive unit 208. Also, by following the control program stored in the ROM 204, the CPU 202 drives a control valve 31 and a pump 32 by means of a liquid-amount adjustment drive unit 212 based on a detection result from a liquid level sensor 41 provided on the sub tank 26, as will be described later. Further, by following the control program stored in the ROM 204, the CPU 202 drives a control valve 21 and a pump 22 by means of a circulation drive unit 214, as will be described later. Information such as ejection data (print data) is input from a host apparatus 220 through an input interface 216, and that input information is written to an RAM 206.
(Configuration of Ejection Head)
In the ejection head 14, an actuator (not illustrated) is installed in each of pressure chambers 19 provided individually for the ejection ports 15. The actuator may only need to be an element capable of generating energy with which the ejection material can be ejected in a fine droplet, e.g. a droplet of 1 picolitre (pL). Specific examples of the actuator include a piezoelectric element, a heat element, and so on. A piezoelectric element is usable under high temperature conditions since the influence of temperature change (temperature rise) on ejection characteristics is smaller when a piezoelectric element is used than when a heat element is used. Thus, various kinds of ejection materials such as resins with high viscosity are usable. Also, generally, when a heat element is used, the manufacturing cost can be lower. The actuator in this embodiment is a piezoelectric element. By controlling drive of the piezoelectric element, the capacity of the pressure chamber 19 is changed to eject the ejection material in the pressure chamber 19 from the ejection port 15. The piezoelectric element may be installed using a micro electro mechanical system (MEMS) technique.
Each pressure chamber 19 communicates with a common liquid chamber 20, and this common liquid chamber 20 communicates with a first storing space 5 in the storing container 13. The ejection material to be ejected from the ejection ports 15 is supplied to the pressure chambers 19 from the first storing space 5 through the common liquid chamber 20. The ejection head 14 has no control valve between itself and the first storing space 5. For this reason, the internal pressure of the first storing space 5 is controlled to be a negative pressure slightly lower than the atmospheric pressure outside the ejection ports 15 of the ejection head 14 (outside air pressure). This negative-pressure control allows the ejection material in each ejection port 15 to form a meniscus 17 at its interface with the outside air, and thereby prevents leakage (dripping) of the ejection material from the ejection port at an unintended time. In this embodiment, the internal pressure of the first storing space 5 is controlled to be a negative pressure lower than the outside air pressure by 0.40±0.04 kPa.
(Configuration of Storing Container)
As illustrated in
The housing 11 has a first opening portion opening on the side that faces the housing 12, and a second opening portion opening on the side that faces the ejection head 14. The entire plane of the first opening portion is covered and sealed by the first film 1, and the first storing space 5 is formed between the inner surface of the housing 11 and the first film 1. The second opening portion communicates with the common liquid chamber 20 in the ejection head 14, so that the first storing space 5 communicates with the outside space through the ejection head 14. The first storing space 5 is filled with the ejection material, and the interface between the ejection material and the outside air is situated inside the ejection ports 15, as illustrated in
The housing 12 has an opening portion opening on the side that faces the housing 11. The entire plane of this opening portion is covered and sealed by the second film 2, and a second storing space 6 is formed between the inner surface of the housing 12 and the second film 2. The second storing space 6 is filled with the operating liquid 35. Also, the second storing space 6 communicates with the inside of the sub tank 26 through a tube 24 and can communicate with the inside of the sub tank 26 also through a tube 23 equipped with the control valve 21 and the pump 22. The sub tank 26 is a liquid storing unit that holds the operating liquid 35. Inside the second storing space 6, the operating liquid 35 functions as a liquid filler. The first film 1 and the second film 2 each function as a barrier between the first storing space 5 and the second storing space 6.
(Materials of Films)
The materials of the first film 1 and the second film 2 may only need to be materials resistant to the ejection material and the operating liquid in view of the liquid contact property and the like. For example, tetrafluoroethylene-per-fluoroalkyl vinyl ether copolymer (PFA), ethylene tetrafluoroethylene (ETFE), and a Teflon (registered trademark)-based fluororesin such as polytetrafluoroethylene (PTFE) are usable. Also, examples include polyethylene (PE), polyvinyl chloride (PVC), polyethylene terephthalate (PET), polyvinyl alcohol (PVAL), polyvinylidene chloride (PVDC), and a polyamide synthetic resin such as nylon. The first film 1 and the second film 2 may be of the same material (substance and thickness) or of different materials. For example, it is possible to use a material resistant to the ejection material, such as PTFE, for the first film 1 and use a nylon-based material resistance to the operating liquid for the second film 2.
(Relation Between Pressure in First Storing Space and Pressure in Second Storing Space)
Whenever a difference in internal pressure is produced between the first storing space 5 and the second storing space 6, the first film 1 and the second film 2, each of which has flexibility, move as a single body toward the side with the lower internal pressure and stop moving when the difference in internal pressure disappears. In this way, the internal pressures of the first storing space 5 and the second storing space 6 can be maintained equal to each other.
To give a more specific description, as the ejection material is ejected from the ejection head 14, the volume of the ejection material inside the first storing space 5 decreases by the amount of the ejected ejection material, so that the internal pressure of the first storing space 5 drops. At the same time, the internal pressure of the second storing space 6 becomes higher than the internal pressure of the first storing space 5. Since the flexible first film 1 and second film 2 are linked to each other by the linking portions 3 so as to be movable together, they move as a single body toward the first storing space 5. Simultaneously, the operating liquid 35 is sucked from the sub tank 26 into the second storing space 6 through the tube 24. As a result, the internal pressures of the first storing space 5 and the second storing space 6 become equal to each other into an equilibrium state again.
As illustrated in
This embodiment is an ejection-material ejection apparatus applicable to a printing apparatus capable of ejecting a liquid amount of about 1 pL or less, as mentioned above. In this embodiment, the ejection material is ink for printing images, and the diameter of the ejection ports 15 is about 10 micrometer (μm). Also, in this embodiment, each of the ejection material and the operating liquid has a density substantially equal to that of water. In this embodiment, the height difference Δ H is set within the above-mentioned range of 41 mm±4 mm to form the meniscus 17 of the ejection material inside each ejection port 15 under the above conditions. Also, for example, the diameter of the ejection ports 15 in low-resolution printing apparatuses is several tens of μm, and the diameter of the ejection ports in three-dimensional printers using resin or the like as the ejection material is several hundreds of μm. Thus, the diameter of the ejection ports 15 varies by the type of apparatus to which the ejection apparatus is applied, and physical properties of the ejection material (e.g. density, viscosity, etc.) also vary by the type of apparatus to which the ejection apparatus is applied. Hence, the height difference Δ H is set as appropriate for the apparatus to which the ejection apparatus is applied, by taking the influence of the gravity, capillary force, surface tension, and so on into account.
(Corrective Operation)
A corrective operation is executed when the height of the liquid level of the operating liquid inside the sub tank 26 deviates from the height of a reference liquid level (in this embodiment, a height lower than the ejection ports 15 by 41 mm) outside a predetermined range (in this embodiment, the range of the height of the reference liquid level±4 mm). This corrective operation is a ‘liquid level adjustment’ operation of putting the height of the liquid level of the operating liquid inside the sub tank 26 within the predetermined range by moving the operating liquid between the main tank 34 and the sub tank 26.
The liquid level sensor 41 is installed on the sub tank 26. The liquid level sensor 41 in this embodiment is a sensor capable of detecting the height of the liquid level of the operating liquid inside the sub tank 26 and its change (displacement). The main tank 34 and the sub tank 26 can communicate with each other through a tube 33 equipped with the control valve 31 and the pump 32. By driving the control valve 31 and the pump 32, the height of the liquid level of the operating liquid inside the sub tank 26 is controlled to be within a desired range (liquid level adjustment). Specifically, when the liquid level sensor 41 detects that the height of the liquid level of the operating liquid 35 inside the sub tank 26 has dropped below the predetermined range, the control valve 31 is opened and the pump 32 is driven to supply the operating liquid from the main tank 34 to the sub tank 26. Further, when the liquid level sensor 41 detects that the height of the liquid level of the operating liquid 35 inside the sub tank 26 is within the predetermined range, the drive of the pump 32 is stopped and the control valve 31 is closed to stop the supply of the operating liquid from the main tank 34 to the sub tank 26. Also, the control valve 31 and the pump 32 can be controlled to supply the operating liquid back from the sub tank 26 to the main tank 34. In this way, the height of the liquid level inside the sub tank 26 is maintained within the predetermined range.
(Sub Tank)
The sub tank 26 is preferably disposed such that the ceiling surface (the uppermost portion in the vertical direction) of its inside is disposed lower than the ejection ports 15 of the ejection head 14 in the vertical direction. With this arrangement, the position of the liquid level of the operating liquid 35 inside the sub tank 26 will not be higher than the position of the ejection ports 15 at the ejection surface even if the operating liquid is supplied from the main tank 34 until the sub tank 26 becomes full in the above liquid level adjustment. In other words, the ceiling surface of the sub tank 26 limits the height of the liquid level of the operating liquid 35 inside the sub tank 26, so that the relative positional relation (height relation) between the liquid level of the operating liquid 35 and the ejection ports in the vertical direction is maintained and the height difference Δ H will never reach 0 (zero). Hence, the internal pressures of the first storing space 5 and the second storing space 6 can always be maintained at negative pressure relative to the outside air pressure, thereby making it possible to prevent leakage and dripping of the ejection material from the ejection ports 15.
(Circulation System)
The second storing space 6 and the sub tank 26 communicate with each other through the tube 24, and can communicate with each other also through the tube 23, which is equipped with the control valve 21 and the pump 22. Bubbles may possibly enter the tube 24 when the storing container 13 is demounted once from the ejection apparatus and then mounted again. In that case, the bubbles in the tube 24 can be removed by opening the control valve 21 and actuating the pump 22 to circulate the operating liquid 35 through the tube 24, the second storing space 6, and the tube 23 and thereby send the operating liquid to the sub tank 26. The control valve 21 is closed while the pump 22 is not used, and is opened while the pump 22 is used.
(Pump)
Examples of the pump 22 and the pump 32 include syringe pumps, tube pumps, diaphragm pumps, gear pumps, and so on. However, the pump 22 and the pump 32 may only need to have the function of a liquid sender and are therefore not limited to pumps. Thus, it is possible to select liquid senders suitable for the ejection-material ejection apparatus.
(First Film 1 and Second Film 2)
As described earlier, the space inside the storing container 13 is separated into the first storing space 5 and the second storing space 6 by the flexible member with the two films 1 and 2, which function as barriers. In this embodiment, the first film 1 and the second film 2 move together and can therefore deform and move as a single body. This makes it possible to control the pressure inside the ejection head 14. If the first film 1 and the second film 2 were not link to each other and could be deformed and moved independently, the pressure inside the ejection head 14 could not be controlled as described above though adjustment of the height of the liquid level of the operating liquid inside the sub tank 26.
A specific case will be described in which an attempt is made to adjust the position of the liquid level (the height of the liquid level) of the operating liquid inside the sub tank 26 to a position lower than the position of the ejection surface, at which the ejection ports 15 open, in a configuration where the first film 1 and the second film 2 can be deformed and moved independently. In this case, the operating liquid inside the second storing space 6 attempts to move by gravity into the sub tank 26 below the second storing space 6 in the vertical direction. Since the second film 2 is movable independently of the first film 1, it moves away from the first film 1 in the X direction in
As described above, with the configuration in which the first film 1 and the second film 2 do not move together, the pressure inside the ejection head 14 cannot be controlled through adjustment of the position of the liquid level of the operating liquid 35.
In contrast, in the embodiment of the present invention, the first film 1 and the second film 2 are connected to each other at multiple positions by the linking portions 3, which are distributed on the surfaces of the first film 1 and the second film 2 facing each other, so that the first film 1 and the second film 2 move together in the same direction at the same time. This makes it possible to control the pressure inside the ejection head 14.
Specifically, the first storing space 5 communicates with the outside air through the ejection ports 15 of the ejection head and, at the interface between the ejection material in each of the ejection ports and the outside air, the ejection material is subjected to forces such as the atmospheric pressure, the gravity on the ejection material, and the flow resistance and surface tension by the inner wall of the ejection port. The balance between these forces is such that the ejection material tries to flow out from the ejection port and move the first film 1 in the—X direction, which is opposite from the X direction in
(Storing Container)
The spacer 16 is provided in its upper portion with an air suction port 83 communicating with the outside and is provided in its lower portion with a liquid discharge port 84 communicating with the outside. A liquid leakage sensor 42 to be described later is disposed under this liquid discharge port 84. As will be described later, if the film 1 or 2 is damaged and the liquid in the storing space 5 or 6 leaks out into the inter-film space 4, that liquid will be guided by the spacer 16 into the liquid discharge port 84, pass through the liquid discharge port 84, drip downward, and be detected by the liquid leakage sensor 42. Although an inner surface of the spacer 16 is simplified and illustrated as a flat surface in
The protruding portion of the flexible member, including the two films 1 and 2, may be tapered. Providing a curved-shape portion (curved portion) R at each corner and edge of the protruding portion can further facilitate deformation of the flexible member. The inner surfaces of the first storing space 5 and the second storing space 6 may be shaped to extend along such a shape of the flexible member.
The first film 1 and the second film 2 need to move smoothly as a single body as the ejection material is ejected. For this reason, the areal density (amount (quantity, area) per unit area) of the linking portions 3 between them is preferably higher at a center region 8 surrounded by a tapered-shape portion (tapered portion) T and the curved portions R than at the tapered portion T and the curved portions R. The center region 8 is a region that directly receives pressure that causes the films to move together, and is therefore preferably flat. However, the center region 8 may not be strictly flat but may be gently curved, for example. Also, among the tapered portion T, the curved portions R, and the center region 8, the areal density of linking portions 3 is preferably lowest at the curved portions R since the higher the areal density of linking portions 3, the higher the stiffness.
A soft material or a thin material may be used for at least one of the first film and the second film to lower the stiffness of the flexible member as a whole so that the first film and the second film can be moved smoothly as a single body. As for the shape of each film itself, the thickness may be varied in some parts as illustrated in
As illustrated in
The operating liquid thus pushed out of the second storing space 6 raises the liquid level of the operating liquid inside the sub tank 26. By detecting this rise in liquid level with the liquid level sensor 41 (see
A case where the height of the liquid level of the operating liquid 35 inside the sub tank 26 changes due to different reasons other than film damage will now be considered.
First, as mentioned earlier, when the operating liquid 35 in the sub tank 26 is replenished from the main tank 34 in order to maintain the value of the height difference Δ H, illustrated in
As described above, if part of the second film 2 is damaged, it is possible to detect the occurrence of the film damage by detecting the consequential rise in liquid level of the operating liquid 35 inside the sub tank 26 with the liquid level sensor 41.
Also, in
Next, a case where part of the first film 1 is damaged will be described. The state and behavior of the ejection apparatus in this case are similar to those in the case where part of the second film 2 is damaged. Specifically, if part of the first film 1 is damaged, air bubbles 74 will be sucked into the first storing space 5 through the damaged spot. The pressure in the air bubbles 74 is equal to the atmospheric pressure. Thus, the air bubbles 74 raise the internal pressure of the first storing space 5 and accordingly makes this internal pressure higher than the internal pressure of the second storing space 6. As a result, the first film 1 and the second film 2, each functioning as a barrier, move as a single body toward the second storing space 6 and thereby push out the operating liquid 35 inside the second storing space 6 into the sub tank 26. The operating liquid thus pushed out raises the liquid level of the operating liquid inside the sub tank 26, and the liquid level sensor 41 detects this rise (see
As described above, regardless of which is damaged, the first film 1 or the second film 2, it is possible to detect that one of the films has been damaged by using the liquid level sensor 41 and the flow speed sensor 77 together with the later-described liquid leakage sensor 42. Also, regardless of which is damaged, the first film 1 or the second film 2, the ejection material and the operating liquid will remain separated from each other and will never contact each other.
Also, if film damage occurs, the internal pressure of the first storing space 5 can rise until becoming equal to the outside air pressure. This leads to a possibility that the ejection material fails to maintain the state of forming the meniscus 17 and drip out of the ejection port 15 at an unintended time. However, the ejection apparatus in this embodiment can detect abnormality at the point when the internal pressure of the first storing space 5 turns to rise. Then, by issuing an abnormality alarm based on that detection, it is possible to implement dripping prevention before the ejection material drips. Examples of the dripping prevention include capping the ejection ports, controlling the negative pressure in the second storing space by using a pressure controller, and so on.
In this embodiment, the inter-film space 4 between the first film 1 and the second film 2 communicates with the outside air and is therefore at the equal pressure to the atmospheric pressure. However, the pressure difference between the inter-film space 4 and the storing spaces 5 and 6 can be maintained also by providing a valve for controlling the communication between the inter-film space 4 and the outside air, adjusting the air pressure inside the inter-film space 4 to the atmospheric pressure in advance with the outside air, and then closing the valve to make the inter-film space 4 a sealed space. If the first film 1 or the second film 2 is damaged in this state, the gas inside the inter-film space 4 will flow into the first storing space 5 or the second storing space 6. In this case, the amount of inflow of the gas is at most the capacity of the space between the first film 1 and the second film 2. Thus, it is possible to prevent dripping of the ejection material from the ejection ports by detecting film damage with a significantly small amount of inflow of the gas as compared to the case where the inter-film space 4 communicates with the outside air.
Film damage occurs due to various reasons. For example, in a printing apparatus using ink as the ejection material, its films serving as barriers may possibly get a hole due to manufacturing variations. Also, the films serving as barriers may possibly get a hole due to their repetitive movement and deformation inside the storing container 13. Also, many problems occur with a configuration in which the operating liquid gets mixed into the ejection material as soon as the films get a hole, as in the conventional example discussed in PTL 1. Specifically, if water serving as the operating liquid gets mixed and diffused in ink for printing images, the ink is diluted by the water and printed images will be dimmer. Also, since the operating liquid contains an additive, which is an impurity, a deposit in the operating liquid or particles in the operating liquid may possibly clog the ejection ports 15 measuring about 10 μm in diameter and lead to a condition where the ejection material cannot be ejected. Thus, in a situation where the films serving as barriers get a hole, it is extremely important to prevent contact between or mixing of the ejection material and the operating liquid.
In a case where the ejection apparatus in this embodiment is employed as a photosensitive-resist coating apparatus for a semiconductor exposure apparatus, the advantageous effect achieved by preventing contact between the ejection material and the operating liquid is greater. In photosensitive-resist coating apparatuses, the density of ejection patterns is so low that the diameter of the ejection ports 15 is about 10 μm, as with high-density printing apparatuses. For this reason, clogging by impurities is a serious problem. Further, the photosensitive resist is required to satisfy an essential requirement that the concentration of ions of metals such as Na and Mg dissolved in the resist is less than several ppb. Even if the photosensitive resist and the operating liquid do not get mixed with each other, only contact between them allows metal ions in the operating liquid to move into the photosensitive resist and causes metal ion contamination. In addition, if the photosensitive resist with the metal ion contamination is applied to a wafer, the metal ion contamination spreads to all production apparatuses at the next and subsequent stages that contact this wafer, which is a serious problem. Thus, it is extremely important to be able to detect the occurrence of film damage without the ejection material and the operating liquid contacting each other.
Also, based on the height of the liquid level measured by the liquid level sensor 41, the control apparatus (the CPU 202 in
Meanwhile, the operating liquid 35 is supplied from the main tank 34 to the sub tank 26 to maintain the value of the height difference Δ H within a certain range, as described earlier. For this supply operation, the amount of the liquid to be sent is already known, as described earlier, and also the liquid-level change speed is calculated by the control apparatus. If film damage occurs while the operating liquid 35 is being sent, the liquid-level change speed will be detected to be higher than the known value. This makes it possible to recognize an abnormal state resulting from the film damage.
Also, when the height difference Δ H is corrected, it is also possible to calculate the cumulative value of the amount of the operating liquid supplied from the main tank 34 to the sub tank 26 for replenishment. The cumulative value of the amount of the operating liquid supplied for replenishment is equal to the amount of decrease of the ejection material inside the first storing space 5. Thus, it is possible to simultaneously figure out the total amount of the ejection material ejected and the amount of the ejection material remaining inside the first storing space 5. This function makes it possible to figure out the relation between the duration of use of the storing container 13 and the amount of the remaining liquid and calculate a predicted remaining life.
As described above, if either film is damaged and a hole 73 is formed therein, air bubbles 74 will be sucked into the storing space 5 or 6, so that the internal pressure of that storing space becomes closer to the outside air pressure. Also, it is possible that the film is damaged to such a great extent that a hole 78 with a diameter of approximately 200 μm or larger is formed, as illustrated in
Also, for a liquid ejection apparatus using photosensitive resist as its ejection liquid and using water with a preservative mixed therein as its operating liquid, it is possible to determine whether leaking liquid is the ejection liquid or the operating liquid by using an optical liquid leakage sensor as the liquid leakage sensor 42. In this case, the optical liquid leakage sensor has sensitivity individually to the ejection liquid and the operating liquid. However, in the case of using a conduction-short circuit detection-type leakage sensor is used, the sensor may have sensitivity to the photosensitive resist but not to the water or have sensitivity to the water but not to the photosensitive resist, depending on the type. These cases can be handled by using multiple types of leakage sensors. Specifically, by using a leakage sensor including a detection unit that detects the photosensitive resist and a detection unit that detects the water, it is possible to detect film damage while distinguishing whether it is damage of the film 1 or of the film 2.
As described above, in this embodiment, the detection of film damage with the liquid level sensor 41 and the flow speed sensor 77 and the detection of film damage with the liquid leakage sensor 42 can be carried out in parallel. Thus, film damage can be detected and handled quickly and certainly regardless of the extent of the film damage. In particular, since the liquid leakage sensor 42 can directly detect leaking liquid, film breakage (damage) can be detected more certainly. Also, film breakage (damage) can be detected only with this liquid leakage sensor 42 as well.
In
Also, a capacitive detection method or an optical method can be employed as the method of detecting the liquid level of the leaking liquid inside the leaking liquid tank 37 with the liquid level sensor 38. In the case of using an optical liquid level sensor, at least part of the leaking liquid tank is made of a transparent material, and the liquid level is detected through this transparent part. In this case, it is also possible to determine which has been damaged, the film 1 or the film 2, by further disposing a sensor that determines the type of leaking liquid based on the color or refractive index of the leaking liquid, as in the conventional example discussed in PTL 2.
The exit of the liquid discharge port 84 may be shaped to open at the outer lower surface (flat surface) of the storing container 13, as illustrated in
The discharge pump 49, provided for the liquid discharge port 84, sucks the outside air from an air suction port 83 through an inter-film space 4. In this way, leaking liquid (operating liquid or ejection liquid) having leaked out into the inter-film space 4 is sucked and discharged through the discharge tube 48 and quickly reaches and is certainly detected by the liquid leakage sensor 43. The films 1 and 2 do not need to be connected to each other by fusing or the like if the discharge pump 49 and a choke or the like not illustrated can maintain the inside of the inter-film space 4 in a negative-pressure state and bring the films 1 and 2 into tight contact with each other at least partly such that they can move as a single body. The discharge pump 49 does not need to be operated constantly but may be intermittently driven at regular time intervals. The liquid leakage sensor 43 may be configured to detect the operating liquid and the ejection liquid without distinguishing one from the other or may be configured to be capable of detecting them while distinguishing one from the other.
Imprinting apparatuses are used to manufacture products as typified by semiconductor devices. The imprinting apparatus 50 presses a mold 58 having a molding pattern against uncured resin (resist) 90 applied to a shot region on a substrate 59 and, in this state, irradiates the resin 90 with light 60 (e.g. ultraviolet rays) to cure the resin 90. Thereafter, the imprinting apparatus 50 separates the mold 58 from the cured resin 90. As a result, the pattern on the mold 58 is transferred to the substrate 59. The imprinting apparatus 50 in this embodiment is an imprinting apparatus employing an optical imprinting method and includes a light irradiation unit 88, a mold hold unit 51, a substrate chuck 52, a substrate stage 53, an ejection-liquid ejection apparatus 54, an ejection head 55, a pressure control unit 56, and a control unit 57.
In imprinting, the light irradiation unit 88 irradiates the resin 90 with applies the light 60 through the mold 58. The wavelength of the light 60 is a wavelength suitable for the resin 90 to be cured. The pattern to be transferred, such as a circuit pattern, is formed on the surface of the mold 58 that faces the substrate 59. Quartz or the like that can transmit the light 60 can be used as the material of the mold 58. The mold hold unit 51 includes a mold chuck not illustrated that holds the mold 58, a mold drive mechanism not illustrated that holds this mold chuck movably, and a magnification correction mechanism not illustrated that corrects the shape of the mold 58. The substrate 59 is a silicon wafer, a silicon on insulator (SOI) substrate, a glass substrate, or the like.
On the substrate 59, there are multiple shots as pattern formation regions arranged in a particular shot layout. Each shot is formed on the substrate 59 immediately before imprinting by ejecting the resin 90 stored in the ejection apparatus 54 from the ejection ports of the ejection head 55. The pattern formed on the mold 58 is then impressed into the shot. As a result, a pattern of the resin 90 is formed on the substrate 59. The substrate chuck 52 holds the substrate 59, and the substrate stage 53 holds the substrate chuck 52 movably along with the substrate 59. The substrate stage 53 positions the mold 58 and the substrate 59 with respect to each other after the ejection head 55 applies the resin 90. The imprinting is performed in conjunction with this positioning.
In this series of imprinting actions, movement of the substrate 59 to a shot position, ejection and application of the resin 90, impressing, positioning, curing of the resin 90, releasing of the mold, and movement of the substrate 59 to the next shot position are performed sequentially, and this series of actions is repeated as needed.
The ejection apparatus 54 in this embodiment includes the ejection head 55, a storing container 95, the pressure control unit 56, the control unit 57, and a pressure measurement unit 97. The storing container 95 includes a flexible membrane 94 that separates the inside of the storing container 95 into a first storing space 91 and a second storing space 92. The first storing space 91, which communicates with the ejection head 55, is filled with the resin 90 (ejection material). The control unit 57 controls the ejection head 55 to eject the resin 90 from the ejection ports of the ejection head 55. In the ejection head 55, an actuator is installed in each of pressure chambers provided individually for the ejection ports. The actuator may only need to be an element capable of generating energy with which the resin 90 as the ejection material can be ejected in a fine droplet, e.g. a droplet of 1 pL. Specific examples include a piezoelectric element, a heat element, and so on. The ejection head 55 may not be integrated with the storing container 95 but may be replaceably mounted to the storing container 95. The second storing space 92, which does not communicate with the ejection head 55, is filled with an operating liquid 93. Cooling water or the like used in conventional exposure apparatuses is usable as the operating liquid 93. For example, a liquid obtained by adding preservative, humectant, etc. to water is usable as the operating liquid 93. The second storing space 92 communicates with the pressure control unit 56, which supplies the operating liquid 93, through a communicating member 96.
As illustrated in
The thickness of the flexible membrane 94 is preferably 10 μm or more and 200 μm or less and more preferably 50 μm or less. For the flexible membrane 94, a fluororesin (such as FPA) film or the like that is high in chemical resistance and low in amount of metal dissolution is preferably used, for example.
The pressure measurement unit 97 measures the pressure in the inter-film space 99 and sends the measurement data to the control unit 57 of the liquid ejection apparatus. The control unit 57 detects whether the flexible membrane 94 is damaged based on change in the pressure measurement data. If detecting damage of the flexible membrane 94, the control unit 57 at least stops the ejection of the resin 90 from the ejection head 55 in the imprinting apparatus. The imprinting apparatus includes a control unit that outputs a signal to stop the imprinting apparatus upon detection of damage of the flexible membrane 94.
The pressure control unit 56 includes a tank for the operating liquid 93, a pipe, a pressure sensor, a pump, a valve, and so on. The pressure control unit 56 controls the pressure of the operating liquid 93 inside the second storing space 92. The control unit 57 controls the supply of the operating liquid 93 from the pressure control unit 56 to the second storing space 92 to control the pressure of the resin 90 inside the first storing space 91 indirectly with the flexible membrane 94. As a result, as in the above embodiments, the internal pressures of the first storing space 91 and the second storing space 92 are balanced so as to maintain a negative pressure for forming an appropriate meniscus inside each ejection port of the ejection head 55. This enables good ejection of the resin 90.
As the ejection of the resin 90 from the ejection head 55 in the series of imprinting actions is repeated, the amount of the resin 90 inside the first storing space 91 decreases. Accordingly, the flexible membrane 94 moves so as to decrease the capacity of the first storing space 91 and increase the capacity of the second storing space 92. This movement of the flexible membrane 94 replenishes the operating liquid 93 in the second storing space 92 from the tank for the operating liquid 93 in the pressure control unit 56. The resin 90, used in the imprinting apparatus 50, is a resin in which foreign matters (small particles) and metal ions have been reduced to extremely small amounts, and needs to maintain this state until being ejected from the ejection head 55. The imprinting apparatus 50 in this embodiment holds the resin 90 isolated from the outside of the first storing space 91 during the entire period until the resin 90 inside the first storing space 91 is consumed substantially completely by repetition of ejection of the resin 90. Thus, the resin 90 is free from contact with devices such as a pressure sensor. This makes it possible to suppress increase of foreign matters and metal ions persistently from the state where the resin 90 is sealed in the first storing space 91.
Meanwhile, as illustrated in
As described above, the imprinting apparatus in this embodiment can instantly detect damage of the flexible film. This can enhance the throughput yield of the product (device) manufactured by the imprinting apparatus, and also shorten the time for recovery such as cleaning due to damage of the flexible membrane and accordingly improve the rate of operation.
(Product Manufacturing Method)
An imprinting technique as described above can form three-dimensional structures at once and is therefore applicable to manufacturing techniques for diffractive optical elements and bio chip-type inspection elements. Further, since an imprinting technique as described above can form patterns on the order of nanometers, it is applicable to a wide range of fields such as next-generation semiconductor lithography techniques.
Patterns formed using an imprinting apparatus are permanently used in at least part of various products or temporarily used to manufacture various products. The products refer to electric circuit elements, optical elements, MEMS, recording elements, sensors, molds, and so on. The electric circuit elements include volatile and non-volatile semiconductor memories such as DRAMs, SRAMs, flash memories, and MRAMs, semiconductor elements such as such as LSI circuits, CCDs, image sensors, and FPGAs, and so on. The molds include molds for imprinting and so on.
First, as illustrated in part (a) of
Then, as illustrated in part (d) of
In the above fifth embodiment, the discharge pump 49, provided for the liquid discharge port 84, sucks the outside air from the air suction port 83 through the inter-film space 4. In this case, the film 1 and the film 2 may possibly be brought into tight contact with each other such that the discharge pump 49 attempts to discharge leaking liquid (operating liquid or ejection liquid) having leaked out into the inter-film space 4 but it is difficult make the leaking liquid move and reach the liquid leakage sensor 43.
To address this, in the seventh embodiment of the present invention, the air suction tube 85, connected to the air suction port 83, is equipped with the pressurizing pump 86. By using this pressurizing pump 86 to temporarily suck and pressurize the atmospheric air to send it into the inter-film space 4, the film 1 and the film 2 are prevented from coming into tight contact with each other, thereby facilitating flow of leaking liquid (operating liquid or ejection liquid) having leaked out into the inter-film space 4. In this way, the leaking liquid having leaked out into the inter-film space 4 can be sucked and discharged through the discharge tube 48 and more quickly reach and be certainly detected by the liquid leakage sensor 43.
Also, when the outside air is sucked from the air suction port 83 through the inter-film space 4, the internal pressures of the storing spaces 5 and 6 are negative pressure. Thus, it is preferable to maintain the pressure inside the inter-film space 4 at a negative pressure slightly lower than the atmospheric pressure to cause the outside air to flow into the inter-film space 4 to such an extent that the films come into tight contact with each other partly. Also, the timing to suck the outside air is preferably not when the ejection-material ejection apparatus is ejecting droplets, but when the ejection-material ejection apparatus is not ejecting droplets. In this way, it is possible to prevent the change in the pressure inside the inter-film space 4 from influencing the ejection performance such as the amount and speed of ejection of a droplet.
Also, if, in the fifth embodiment, the film 1 and the film 2 are in tight contact with each other such that it is difficult for leaking liquid to move, as mentioned above, another method to facilitate the movement is to provide protrusions 72 as multiple linking portions between the film 1 and the film 2, as illustrated in
An eighth embodiment of the present invention will now be described with reference to
As in the first embodiment, the internal pressure of the first storing space 5, containing the ejection material, is controlled to a value lower than the outside air pressure by 0.40±0.04 kPa by setting the value of the height difference Δ H to 41 mm±4 mm. In this control, the liquid level of the operating liquid 35 inside the sub tank 26 may only need to be at a position within the range of −37 mm to −45 mm from the position of the ejection surface, at which the ejection ports 15 open, in the Z direction in
On the other hand, to detect rise of the liquid level inside the sub tank 26 upon film damage, a displacement sensor capable of detecting a change in liquid level is needed. For this reason, the liquid level sensor 41 in this embodiment is configured as a displacement sensor capable of detecting a change in position of the liquid level within the range of −25 mm to −55 mm from the ejection ports 15 in the Z direction. The liquid level sensor 41 thus configured has both the function of an upper limit sensor and a lower limit sensor for adjusting the liquid level and the function of a liquid-level displacement sensor for detecting film damage.
When calculating the height difference Δ H, the control apparatus (the CPU 202 in
Meanwhile, the operating liquid 35 is supplied from the main tank 34 to the sub tank 26 to maintain the value of the height difference Δ H within a certain range, as described earlier. For this supply operation, the amount of the liquid to be sent is already known, as described earlier, and also the liquid-level change speed is calculated by the control apparatus. If film damage occurs while the operating liquid 35 is being sent, the liquid-level change speed will be detected to be higher than the known value. This makes it possible to recognize an abnormal state.
With the above configuration, when the height difference Δ H is corrected, it is also possible to calculate the cumulative value of the amount of the operating liquid supplied from the main tank 34 to the sub tank 26 for replenishment. Specifically, the cumulative value of the amount of the operating liquid supplied for replenishment is equal to the amount of decrease of the ejection material inside the first storing space 5. Thus, it is possible to simultaneously figure out the total amount of the ejection material ejected and the amount of the ejection material remaining inside the first storing space 5. This function makes it possible to figure out the relation between the duration of use of the storing container 13 and the amount of the remaining liquid and calculate a predicted remaining life.
A ninth embodiment of the present invention will now be described with reference to a drawing. The ninth embodiment is a configuration that detects operating liquid pushed out into the sub tank 26 due film damage by using means different from the eighth embodiment. The basic configuration of this embodiment is similar to that of the eighth embodiment. Only a characteristic configuration will therefore be described below.
On the other hand, when the ejection material is ejected from the ejection ports 15, the operating liquid is sucked (supplied) from the sub tank 26 in the amount of this ejection toward the second storing space 6. Since the operating liquid thus sucked travels through the tube 24, its flow speed can be detected by the flow speed sensor 77, but its direction of flow is opposite from the direction of flow upon occurrence of film damage. Thus, the flow of the operating liquid due to ejection of the ejection material and the flow of the operating liquid due to film damage are opposite from each other in plus/minus sign of the value of the flow speed and can therefore be clearly distinguished from each other.
Also, when the operating liquid 35 in the sub tank 26 is replenished from the main tank 34 to maintain the value of the height difference Δ H within the predetermined range, the sending of the liquid is done through the tube 33, and the tube 24 is not involved in it. Thus, the flow speed sensor 77 detects no flow speed.
Thus, with the configuration of this embodiment, the occurrence of film damage can be detected based on the flow speed detection by the flow speed sensor 77. Note that a similar advantageous effect can be achieved also by using a flow rate sensor instead of the flow speed sensor 77. Specifically, the occurrence of film damage can be detected by detecting the flow rate of the operating liquid 35 traveling from the second storing space 6 toward the sub tank 26 with a flow rate sensor.
In this embodiment too, even if the first film 1 or the second film 2 is damaged, the ejection material and the operating liquid will not contact each other since they are separated from each other. This makes it possible to prevent deterioration of the ejection material by contact.
Also, if film damage occurs, the internal pressure of the first storing space 5 can rise until becoming equal to the outside air pressure. This leads to a possibility that the ejection material inside each ejection port 15 fails to maintain the state of forming the meniscus 17 and drips out of the ejection port 15 at an unintended time. However, the ejection apparatus in this embodiment can detect abnormality at the point when the internal pressure of the first storing space 5 turns to rise, and issue an abnormality alarm based on that detection. This makes it possible to implement dripping prevention before the ejection material drips.
A 10th embodiment of the present invention will now be described with reference to a drawing. The 10th embodiment is a configuration that directly detects film damage from a change in internal pressure. The basic configuration of this embodiment is similar to that of the eighth embodiment. Only a characteristic configuration will therefore be described below.
With the configuration of this embodiment, rise in internal pressure can be detected directly. This makes it possible to detect abnormality quickly after its occurrence and issue an abnormality alarm based on that detection. It is therefore possible to implement dripping prevention before the ejection material drips.
In this embodiment too, even if the first film 1 or the second film 2 is damaged, the ejection material and the operating liquid will not contact each other since they are separated from each other. This makes it possible to prevent deterioration of the ejection material by contact.
In this embodiment, one pressure sensor is provided for each storing space, therefore two pressure sensors in total. However, a similar advantageous effect can be achieved also by providing a pressure sensor for either one of the storing spaces.
An 11th embodiment of the present invention will now be described with reference to a drawing. The 11th embodiment is a configuration including multiple means for detecting the occurrence of film damage. The basic configuration of this embodiment is similar to that of the eighth embodiment. Only a characteristic configuration will therefore be described below.
In this configuration, upon occurrence of film damage, air bubbles are sucked into the corresponding storing space, so that the internal pressure of the second storing space 6, which has been adjusted to negative pressure, starts rising and the operating liquid 35 flows into the sub tank 26 from the second storing space 6. Since the ceiling surface of the inside of the sub tank 26 is lower in height than the ejection ports 15 of the ejection head 14, the sub tank 26 will be full before the internal pressure of the second storing space 6 reaches the pressure equal to the atmospheric pressure. Thereafter, the operating liquid 35 overflows from inside the sub tank 26 to the outside through the tube 25. The overflowing operating liquid 35 is detected by the full-level sensor 28.
Also, as film damage occurs and air bubbles are sucked into the corresponding storing space, the ejection material or the operating liquid moves (leaks) from the storing space into the inter-film space 4. This ejection material or operating liquid then drip by gravity. The dripping ejection material or operating liquid is detected by the leakage sensor 42.
With the above configuration, if film damage occurs, it is possible to detect when the sub tank 26 becomes full, before the internal pressure of the corresponding storing space becomes equal to the atmospheric pressure. For example, even if the liquid level sensor 41 is malfunctioning and not detecting any change in height of the liquid level and therefore failing to detect film damage, it is still possible to detect the film damage by detecting the leakage of the operating liquid 35 with the full-level sensor 28 or by detecting the leakage of the ejection material or the operating liquid with the leakage sensor 42.
As described above, in this embodiment, redundant detecting functions using multiple detectors prevents failure to detect film damage. Note that although this embodiment uses three detectors, namely, the liquid level sensor 41, the full-level sensor 28, and the leakage sensor 42, the present invention is not limited to this. Specifically, in the present invention, there may be one detector or detecting function to detect the occurrence of film damage, and two or more detectors or detecting functions may be used to enhance the effect of preventing failure to detect the occurrence of film damage.
In this embodiment too, even if the first film 1 or the second film 2 is damaged, the ejection material and the operating liquid will not contact each other since they are separated from each other. This makes it possible to prevent deterioration of the ejection material by contact.
If film damage occurs, the internal pressure of the first storing space 5 can rise until becoming equal to the outside air pressure. This leads to a possibility that the ejection material inside each ejection port 15 fails to maintain the state of forming the meniscus 17 and drips out of the ejection port 15 at an unintended time. However, in this embodiment, it is possible to detect abnormality before the internal pressure of the ejection head reaches the atmospheric pressure, and issue an abnormality alarm based on that detection. It is therefore possible to implement dripping prevention before the ejection material drips.
A 12th embodiment of the present invention will now be described with reference to a drawing. The 12th embodiment is a configuration in which the inter-film space is a sealed space. The basic configuration of this embodiment is similar to that of the eighth embodiment. Only a characteristic configuration will therefore be described below.
The body of the gas tank 37 is situated outside the storing container 13, and the internal space (pooled air) of the body of the gas tank 37 communicates with the inter-film space 4. A tank with such strength as not to be deformed by change in internal pressure under the use condition (pressure condition) in this embodiment is used as the gas tank 37.
As mentioned above, if the first film 1 or the second film 2 is damaged, the air in the inter-film space 4 will pass through the damaged spot of the film and be sucked into the first storing space or the second storing space in the form of air bubbles 74. Also, this rises the pressure inside the storing space and accordingly pushes the operating liquid 35 out of the second storing space 6 toward the sub tank 26. At the same time, air outside the inter-film space 4, specifically, the air in the internal space of the gas tank 37, is sucked into the inter-film space 4 to supply air of the volume of the air bubbles 74 sucked into the storing space. Consequently, a flow of air is formed.
The flow rate sensor 78 detects the flow of air moving from the internal space of the gas tank 37 toward the inter-film space 4 at a significant flow rate. Thus, the occurrence of the film damage can be detected.
Meanwhile, the same advantageous effect can also be achieved by similarly using a flow speed sensor in place of the flow rate sensor 78. Specifically, it is possible to detect the occurrence of film damage by using a flow speed sensor to detect a flow of air moving from the internal space of the gas tank 37 toward the inter-film space 4 at a significant flow speed. To enhance the accuracy of the detection with the flow speed sensor, it is desirable to narrow the flow speed sensor's suction port to increase the flow speed.
In this embodiment too, even if the first film 1 or the second film 2 is damaged, the ejection material and the operating liquid will not contact each other since they are separated from each other. This makes it possible to prevent deterioration of the ejection material by contact.
If film damage occurs, the internal pressure of the first storing space 5 can rise until becoming equal to the outside air pressure. This leads to a possibility that the ejection material inside each ejection port 15 fails to maintain the state of forming the meniscus 17 and drips out of the ejection port 15 at an unintended time. However, upon occurrence of film damage, the ejection apparatus in this embodiment can detect the abnormality quickly after its occurrence based on the movement of air from the outside to the inside of the inter-film space 4 resulting from the film damage, and issue an abnormality alarm based on that detection. It is therefore possible to implement dripping prevention before the ejection material drips.
The configuration in which the inter-film space 4 is a sealed space limits the volume of air that flows into the storing space from the inter-film space 4 upon occurrence of film damage and accordingly reduces the increase in the internal pressure of the storing space. Hence, film damage can be detected and dripping of the ejection material from the ejection ports can be prevented with a smaller amount of inflow of gas.
A 13th embodiment of the present invention will now be described with reference to a drawing. The 13th embodiment is a configuration provided with a pressure adjustment mechanism capable of adjusting the internal pressure of the sub tank 26 among multiple pressures. The basic configuration of this embodiment is similar to that of the eighth embodiment. Only a characteristic configuration will therefore be described below.
When an ejection operation is performed to eject the ejection material from the ejection ports, the opening/closing of the three-way valve 46 is controlled to make the sub tank 26 communicate with the atmosphere and not communicate with the pressure adjustment tube 45.
To set the internal pressure of the sub tank 26 to a lower pressure (negative pressure) than the atmospheric pressure, the pump 48 is operated with the regulator 47 set to a predetermined pressure and the opening/closing of the three-way valve 46 is controlled to make the sub tank 26 and the pressure adjustment tube 45 communicate with each other. In this way, the internal pressure of the sub tank 26 can be controlled to be the negative pressure.
The internal pressure of the sub tank 26 can be controlled among multiple pressures by controlling the regulator 47. For example, the internal pressure of the sub tank 26 may be controlled with the regulator 47 to be a pressure (second pressure) that is lower than the pressure suitable for an ejection operation (first pressure) and does not break the meniscus of the ejection material in each ejection port 15. The pressure suitable for an ejection operation (first pressure) is, in other words, a pressure suitable as the steady internal pressure in the ejection head at the time of performing an ejection operation. Also, the pressure that is lower than the first pressure and does not break the meniscus of the ejection material in each ejection port 15 is a pressure at which the ejection material forms a meniscus in the ejection port and the position where the meniscus is formed is within the ejection port.
The pressure that does not break the meniscus of the ejection material in each ejection port 15 varies depending on factors such as the diameter of the ejection port, the surface tension of the ejection material, and so on, but may be a value lower than the outside air pressure by 0.40 kPa, for example.
To prevent change in the amount of ejection of the ejection material and the flying speed of the ejection material, the above control on the internal pressure of the sub tank 26 is desirably performed during non-ejection operations in which no ejection operation is performed.
Changing the internal pressure of the sub tank 26 may possibly change the internal pressures of the first storing space 5 and the second storing space 6 as well such that the ejection material leaks or drips out of the ejection ports 15, which communicate with the first storing space 5. Considering this possibility, it is desirable to perform the control to switch the internal pressure of the sub tank 26 while the ejection material is not situated at the ejection position for ejection from the ejection head 14 (e.g. the meniscus forming position illustrated in
Also, to reduce troubles that can be caused by leakage and dripping of the ejection material, the control to switch the internal pressure of the sub tank 26 is desirably performed while the ejection head 14 is not moving, during replacement of the ejection-material storing container, and during maintenance of the ejection head 14.
In this embodiment, the flow speed of the operating liquid 35 flowing from the second storing space 6 toward the sub tank 26 due to film damage can be increased by making the inside of the sub tank 26 a closed space and setting the internal pressure of the sub tank 26 below the atmospheric pressure. This makes it possible to quickly detect the rise in liquid level inside the sub tank 26 and quickly detect the occurrence of film damage.
In this embodiment too, even if the first film 1 or the second film 2 is damaged, the ejection material and the operating liquid will not contact each other since they are separated from each other. This makes it possible to prevent deterioration of the ejection material by contact.
In this embodiment, the flow speed of the operating liquid 35 flowing from the second storing space 6 toward the sub tank 26 through the tube 24 due to film damage can be increased by making the inside of the sub tank 26 a closed space and setting the internal pressure of the sub tank 26 below the atmospheric pressure. This makes it easier to quickly and accurately detect the flow speed with the flow speed sensor 77 and therefore enables quick and easy detection of the occurrence of film damage.
In this embodiment too, even if the first film 1 or the second film 2 is damaged, the ejection material and the operating liquid will not contact each other since they are separated from each other. This makes it possible to prevent deterioration of the ejection material by contact.
In this embodiment, the inside of the sub tank 26 is made a closed space, and the internal pressure of the sub tank 26 is set to be lower than the atmospheric pressure (to negative pressure). With the internal pressure controlled to be lower (with the absolute value of the negative pressure controlled to be larger), it is possible to increase the flow of the fluid moving from the second storing space 6 toward the sub tank 26 upon occurrence of film damage. This accordingly increases the flow of air flowing into the second storing space 6 from the inter-film space 4 and also increases the flow of air flowing into the inter-film space 4 from the internal space of the gas tank 37 through the connected portion (suction port). This in turn makes the flow rate detection by the flow rate sensor 78 easier and improves the detection accuracy. Hence, film damage can be detected more certainly. A similar advantageous effect can also be achieved by detecting the flow speed with the flow speed sensor 77 in place of the flow rate sensor 78.
In this embodiment too, even if the first film 1 or the second film 2 is damaged, the ejection material and the operating liquid will not contact each other since they are separated from each other. This makes it possible to prevent deterioration of the ejection material by contact.
As illustrated in
The material of the meshed thin resin 101 may only need to be a material resistant to the ejection material and the operating liquid, like the materials of the films 1 and 2. For example, tetrafluoroethylene-per-fluoroalkyl vinyl ether copolymer (PFA), ethylene tetrafluoroethylene (ETFE), and a Teflon (registered trademark)-based fluororesin such as polytetrafluoroethylene (PTFE) are usable. Also, examples include polyethylene (PE), polyvinyl chloride (PVC), polyethylene terephthalate (PET), polyvinyl alcohol (PVAL), polyvinylidene chloride (PVDC), and a polyamide synthetic resin such as nylon.
In a storing container 13 in
Note that the waste-liquid container 70 in the above seventh embodiment is not connected to the lower end of the discharge tube 48 in
In the embodiments of the present invention, leakage of at least one of the ejection material and the operating liquid into the inter-film space and a change in internal pressure of the inter-film space are detected as changes in state of the inter-film space resulting from communication between at least one of the first storing space and the second storing space and the inter-film space. The changes in state of the inter-film space are not particularly limited only to leakage of at least one of the ejection material and the operating liquid and a change in internal pressure as mentioned above but may be, for example, a change of components of the gas inside the inter-film space, a change in temperature of the inter-film space, a change in humidity of the inter-film space, and so on. In sum, it is only necessary to be able to detect a change in state of the inter-film space that occurs when at least one of the first storing space and the second storing space and the inter-film space communicate with each other due to damage of at least one of the first film and the second film, which constitute the flexible membrane, or the like.
Also, changes in multiple states of the inter-film space may be detected. This detection of changes in states of the inter-film space may be done in combination with detection using the liquid level sensor 41 and the flow speed sensor 77 as illustrated in
Although preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments. Various modifications and changes can be made without departing from the gist of the present invention. Combinations of some or all of the components discussed in the embodiments are also encompassed within the scope of embodiments of the present invention.
Also, various detectors such as liquid level sensors, flow speed sensor, and flow rate sensor have been presented in the embodiments. These detectors are used as means for detecting the occurrence of a pressure change resulting from at least one of inflow of a gas from the inter-film space into the first storing space or the second storing space and leakage of a liquid from the first storing space or the second storing space into the inter-film space that are caused by film damage. These detectors can be used alone or in combination as desired. Using them in combination enhances the effect of preventing failure to detect film damage.
Also, the liquid level sensor in the eighth embodiment has been described as a displacement sensor having both the function of upper limit and lower limit sensors and the function of a displacement sensor. However, in the case of using the liquid level sensor along with another detector, this other detector may be used for film damage detection while the liquid level sensor may be used simply as upper limit and lower limit sensors that detect the upper limit and the lower limit only for the purpose of liquid level adjustment.
In the above embodiments, the flexible member has been described as a member including two films, namely, a first film and a second film in a layered configuration. However, in the present invention, the number of films functioning as barriers may only need to be two or more and is not limited to two. A configuration with three or more films can also achieve the same advantageous effect as the configuration with two films as long as the adjacent films are partly connected by linking portions 3, have non-fixed regions on their joining surfaces, and also hold the relation that allows them to move together.
In the examples described hereinabove, upon damage of the first film 1 or the second film 2, the pressure inside the first storing space 5 or the second storing space 6 changes, and this pressure change is detected. Note, however, that the present invention is not limited to these examples. The present invention can bring about a similar advantageous effect even if a spot in the first storing space 5 or the second storing space 6 other than the first film 1 or the second film 2 is damaged and a gas flows into the storing space from the damaged spot or a liquid leaks from the storing space. For example, even when part of the housing 11 or the housing 12 in
While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.
This application claims the benefit of Japanese Patent Applications No. 2017-230766, No. 2017-230287, filed Nov. 30, 2017, No. 2018-136707, filed Jul. 20, 2018, and No. 2018-198690 filed Oct. 22, 2018 which are hereby incorporated by reference wherein in their entirety.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2017-230287 | Nov 2017 | JP | national |
| 2017-230766 | Nov 2017 | JP | national |
| 2018-136707 | Jul 2018 | JP | national |
| 2018-198690 | Oct 2018 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2018/043683 | 11/28/2018 | WO | 00 |
