JP2011126221A - Diaphragm pump, and liquid jetting apparatus - Google Patents

Abstract

Liquid is pumped by a simple and compact configuration.
A shape memory alloy spring is attached to a diaphragm of a diaphragm pump.
When the shape memory alloy spring reaches a predetermined temperature or more, it tries to return to the memorized shape. For this reason, the shape memory alloy spring is heated, the diaphragm is deformed by the force of the spring to return to the memory shape, and the liquid is sucked into the liquid chamber. Next, when the heating is stopped, as the temperature of the spring decreases, the force to return to the memory shape becomes weaker. As a result, the volume of the liquid chamber is reduced by the force that the diaphragm deformed by the shape memory alloy spring returns to the original shape, and the liquid in the liquid chamber is pumped. By doing so, the liquid can be pumped simply by repeating the heating of the shape memory alloy spring and the stopping of the heating, so that the liquid can be pumped with a simple and compact configuration.
[Selection] Figure 5

Description

The present invention relates to a technology for supplying liquid by being mounted in a liquid ejecting apparatus that ejects liquid from an ejection nozzle.

As represented by so-called inkjet printers, liquid ejecting apparatuses that eject liquid from ejection nozzles are known. In this liquid ejecting apparatus, the liquid to be ejected is stored in a dedicated container such as an ink cartridge, and the liquid is ejected by supplying the liquid from the dedicated container to the ejecting nozzle. As a method of supplying the liquid from the dedicated container to the spray nozzle, the method of supplying the liquid by gravity from the dedicated container mounted at a position higher than the spray nozzle is most simply adopted.

In recent years, a method of supplying a liquid from a dedicated container to an injection nozzle using a negative pressure type diaphragm pump has been adopted (Patent Document 1, etc.). in this way,
The air chamber and the liquid chamber (for example, the ink chamber) are separated by a thin deformable partition called a diaphragm, and the liquid in the dedicated container is changed by applying a negative pressure to the air chamber so as to draw the diaphragm. After sucking into the liquid chamber, the negative pressure in the air chamber is released to the atmosphere. Then
The diaphragm that has been deformed by the negative pressure is about to return, and the liquid in the liquid chamber is pumped toward the ejection nozzle. In this method, since the force that the diaphragm tries to return is only applied to the liquid, the amount of liquid ejected from the ejection nozzle can be reduced without performing complicated control such as adjusting the supply amount according to the liquid ejection amount. It becomes possible to supply automatically.

JP 2006-272661 A

However, in the above method using the negative pressure type diaphragm pump, a negative pressure pump for generating a negative pressure for driving the diaphragm pump is required in addition to the diaphragm pump. There is a problem that becomes larger. In particular, in a liquid ejecting apparatus that ejects multiple types of liquid (ink) at the same time as an inkjet printer, a diaphragm pump provided for each type of liquid must be driven at the same time, so a large-capacity negative pressure pump is required. As a result, the space for mounting the negative pressure pump becomes larger, and the liquid ejecting apparatus becomes larger.

The present invention has been made to solve the above-described problems of the prior art,
An object of the present invention is to provide a technique capable of pumping a liquid with a simple and compact configuration while maintaining the advantages of a negative pressure diaphragm pump.

In order to solve at least a part of the problems described above, the diaphragm pump of the present invention employs the following configuration. That is,
A diaphragm pump that sucks liquid from the first passage and pumps it from the second passage,
A liquid chamber connected between the first passage and the second passage and having a volume changed by deformation of the diaphragm;
A first one-way valve provided in the first passage, which allows the liquid to flow into the liquid chamber from the first passage, but does not allow the liquid chamber to flow into the first passage. When,
A second one-way valve provided in the second passage, which allows the liquid to flow out from the liquid chamber to the second passage, but does not allow the liquid passage from the second passage to the liquid chamber. When,
A diaphragm deforming means for deforming the diaphragm;
The diaphragm deformation means includes:
A shape memory alloy spring that is deformed by an external force received from the diaphragm side at a predetermined temperature or lower, and that returns to an initial shape stored in advance when the temperature rises above the predetermined temperature;
And a heating means for heating the shape memory alloy spring to the predetermined temperature or higher.

In such a diaphragm pump of the present invention, the shape memory alloy spring having the property of returning to the memorized shape when heated to a predetermined temperature or more is attached to the diaphragm. This shape memory alloy spring has a normal temperature (that is, a temperature lower than a predetermined temperature).
Then, it is in a state of being deformed by an external force received from the diaphragm side, but when the temperature is raised to a predetermined temperature or more, it tries to return to a previously memorized shape (memory shape). As a result, the diaphragm is deformed to increase the volume of the liquid chamber, so that the liquid can be sucked into the liquid chamber from the first passage through the first one-way valve. Further, when the heating of the shape memory alloy spring is stopped, the temperature of the shape memory alloy spring gradually decreases and the force to return to the memory shape is weakened, so that the shape memory alloy spring is deformed by the force from the diaphragm side (
That is, the shape memory alloy spring returns to the state before heating. Along with this, the volume of the liquid chamber decreases, and as a result, the liquid in the liquid chamber is pumped from the second passage through the second one-way valve.

Thus, in the diaphragm pump of the present invention, the liquid can be sucked from the first passage and pumped from the second passage only by repeating the heating of the shape memory alloy spring and the stop of the heating. . For this reason, since a negative pressure pump for operating the diaphragm pump is not required, liquid can be pumped with a simple and compact configuration.

In the diaphragm pump of the present invention described above, the shape memory alloy may be heated to the predetermined temperature or more by energizing the shape memory alloy spring.

Since the shape memory alloy spring also has electric resistance, the shape memory alloy spring can be heated by so-called Joule heat only by energizing the shape memory alloy spring. As a result, since the shape memory alloy spring can be heated to the predetermined temperature or higher with a simple configuration, the configuration for pumping the liquid can be made a simpler and more compact configuration.

In the diaphragm pump of the present invention described above, when the shape memory alloy spring attempts to return to the initial shape, the diaphragm may be deformed in a direction in which the volume of the liquid chamber increases.

The shape memory alloy spring can be heated relatively quickly by the heating means, but the temperature is lowered by heat radiation to the surrounding air. It is difficult. That is, the shape memory alloy spring can be quickly deformed into a memory shape, but a certain amount of time is required to return the shape memory alloy spring deformed to the memory shape to the state before the deformation. . Therefore, when the shape memory alloy spring is heated to return to the initial shape, the diaphragm is deformed in a direction in which the volume of the liquid chamber increases, and the liquid is sucked into the liquid chamber. By so doing, after the liquid is quickly sucked into the liquid chamber, the liquid can be slowly pumped as the temperature of the shape memory alloy spring decreases. As a result, the liquid can be stably pumped while suppressing the time during which the liquid pumping is interrupted to suck the liquid into the liquid chamber.

The diaphragm pump of the present invention described above may include a restoring spring that is deformed together with the diaphragm by the shape memory alloy spring and generates a reaction force in a direction to restore the deformed diaphragm.

In this way, after the heating of the shape memory alloy spring is stopped, the diaphragm can be restored to its original shape by the reaction force of the restoring spring. For this reason, by appropriately selecting the restoring spring, the diaphragm can be quickly returned to the original shape using the reaction force of the restoring spring. As a result, the amount of liquid that can be pumped per unit time can be increased.

Moreover, the diaphragm pump of the present invention described above is a liquid ejecting apparatus that ejects the liquid in the container from the ejecting nozzle, and can be particularly suitably applied to the use of supplying the liquid to the ejecting nozzle. Therefore, this invention can also be grasped | ascertained with the aspect of the liquid injection apparatus which supplies the liquid in a container to an injection nozzle using the diaphragm pump of this invention mentioned above.

In the liquid ejecting apparatus of the present invention grasped in such a manner, the liquid in the container can be supplied to the ejecting nozzle with a simple and compact configuration. As a result, even when the types of liquids to be ejected increase, it is possible to prevent the liquid ejecting apparatus from becoming large or complicated.

It is explanatory drawing which illustrated the inkjet printer carrying the diaphragm pump of a present Example. FIG. 6 is an explanatory diagram illustrating a state in which an ink cartridge is mounted on a cartridge holder. It is sectional drawing which showed the structure of the diaphragm pump of a present Example. It is explanatory drawing which showed operation | movement of the shape memory alloy spring. It is explanatory drawing which showed the operation | movement in which the diaphragm pump of a present Example pumps ink to an ejection head. It is explanatory drawing which illustrated the conventional diaphragm pump driven by a negative pressure. It is explanatory drawing which showed a mode that the diaphragm pump of the 1st modification used in the state which compressed the shape memory alloy spring operate | moves. It is explanatory drawing which illustrated the diaphragm pump of the 2nd modification provided with the restoring spring other than the shape memory alloy spring.

Hereinafter, in order to clarify the contents of the present invention described above, examples will be described in the following order.
A. Device configuration:
A-1. Inkjet printer structure:
A-2. Structure of the diaphragm pump of this example:
B. Operation of the diaphragm pump of this embodiment:
C. Variations:
C-1. First modification:
C-2. Second modification:

A. Device configuration :
A-1. Inkjet printer structure:
FIG. 1 is an explanatory diagram illustrating an ink jet printer 10 equipped with the diaphragm pump of this embodiment. The illustrated ink jet printer 10 has a substantially box-like appearance, and a front cover 11 is provided in the approximate center of the front surface, and a plurality of operation buttons 1 are adjacent to the front cover 11.
5 is provided. The front cover 11 is pivotally supported on the lower end side, and when the upper end side is tilted forward, an elongated discharge port 12 through which the printing paper is discharged appears. Inkjet printer 1
A paper feed tray 13 is provided on the back side of 0. When printing paper is set in the paper feeding tray 13 and the operation button 15 is operated, the printing paper is sucked from the paper feeding tray 13 so that an image is printed on the front surface and then discharged from the paper discharge port 12. It has become.

An upper surface cover 14 is provided on the upper surface side of the inkjet printer 10.
The upper surface cover 14 is pivotally supported on the back side, and when the upper surface cover 14 is opened by lifting the near side, the internal state of the ink jet printer 10 is checked or the ink jet printer 10 is repaired. Is possible.

In addition, an inkjet head 10 that forms ink dots on a print medium 2 such as printing paper while reciprocating in the main scanning direction, a drive mechanism 30 that reciprocates the ejection head 20, and the like are mounted inside the inkjet printer 10. Has been. A plurality of ejection nozzles are provided on the bottom surface side (side facing the print medium 2) of the ejection head 20, and eject ink from the ejection nozzles toward the print medium. Further, the ink ejected from the ejection nozzle is the ink cartridge 40.
It is housed in a special container called. The ink cartridge 40 is mounted on a cartridge holder 42 provided at a position separate from the ejection head 20, and ink in the cartridge is supplied to the ejection head 20 via the ink tube 44.

In the illustrated inkjet printer 10, it is possible to print a color image using four types of inks of cyan, magenta, yellow, and black. An ejection nozzle is provided for each type of ink. And
The ink in the corresponding ink cartridge 40 is supplied to each ejection nozzle through an ink tube 44 provided for each type of ink.

A drive mechanism 30 that reciprocates the ejection head 20 includes a timing belt 32 having a plurality of teeth formed therein, a drive motor 34 for driving the timing belt 32, and the like. A part of the timing belt 32 is fixed to the ejection head 20. When the timing belt 32 is driven, the ejection head 20 is reciprocated in the main scanning direction while being guided by a guide rail (not shown) extending in the main scanning direction. It becomes possible to make it.

An area called a home position is provided at a position outside the printing area where the ejection head 20 is moved in the main scanning direction, and a maintenance mechanism is mounted at the home position. The maintenance mechanism is pressed against the bottom surface of the ejection head 20 to form a closed space so as to surround the ejection nozzle, and the elevation mechanism (not shown) for raising and lowering the cap member 50 to press against the bottom surface of the ejection head 20. Mechanism and cap member 5
A suction pump (not shown) for generating a negative pressure in a closed space formed by pressing 0 against the bottom surface of the ejection head 20 is configured.

Further, inside the inkjet printer 10, a paper feeding mechanism (not shown) for feeding the printing medium 2 and a control unit 90 for controlling the entire operation are mounted. Operations such as an operation of reciprocating the ejection head 20, an operation of feeding the print medium 2, and an operation of ejecting ink from the ejection nozzle are all performed under the control of the control unit 90.

FIG. 2 is an explanatory view showing a state in which the ink cartridge 40 is mounted on the cartridge holder 42. As shown in the drawing, an ink intake needle 46 for taking ink from the ink cartridge 40 is erected on the bottom of the cartridge holder 42 for each cartridge. In addition, an ink supply port (not shown) is provided at the bottom of the ink cartridge 40. When mounting the ink cartridge 40 to the cartridge holder 42,
With the ink supply port provided in the ink cartridge 40 pressed against the ink intake needle 46 provided in the cartridge holder 42, the ink cartridge 40 is mounted so as to be pushed down. Then, the ink intake needle 46 is inserted from the ink supply port, and the ink in the ink cartridge 40 can be supplied to the cartridge holder 42.

The cartridge holder 42 has a built-in diaphragm pump 100, and the ink flowing from the ink intake needle 46 is guided to the diaphragm pump 100 by an ink passage 42 p provided in the cartridge holder 42. The detailed structure of the diaphragm pump 100 will be described later, but roughly speaking, the main body 1 provided with the diaphragm.
00b, one valve (upstream one valve 100u) provided on the upstream side (ink intake needle 46 side) of the main body 100b, and one valve (downstream one valve 100) provided on the downstream side of the main body 100b.
d) are connected by an ink passage 42p. In addition, the ink passage 42p on the downstream side of the downstream one-side valve 100d passes through the inside of the cartridge holder 42 and opens to the back side. For this reason, the ink taken from the ink intake needle 46 is guided to the main body 100b via the upstream one-side valve 100u and pressurized by the main body 100b, and then the downstream one-side valve 100d and the ink passage 42p. Through this, the pressure is fed from the back side of the cartridge holder 42 toward the ejection head 20.

Further, as described above, the ink jet printer 10 of this embodiment is equipped with the ink cartridges 40 for four colors of cyan, magenta, yellow, and black, and the ink in the ink cartridge 40 is independent of each other. To the ejection head 20. For this reason,
A diaphragm pump 100 for taking ink in the ink cartridge 40 and pumping it to the ejection head 20 is also provided for each ink cartridge 40.

Here, the diaphragm pump is usually driven using a negative pressure, but a negative pressure is generated so that a sufficient negative pressure can be generated even when all the diaphragm pumps are driven simultaneously. Therefore, a sufficient capacity is required for the negative pressure pump. For this reason, although the diaphragm pump itself is a small pump, if a negative pressure pump for driving the diaphragm pump is included, a large mounting space is required, which is one of the factors that increase the size of the inkjet printer 10. It was. In view of these points, in the ink jet printer 10 of the present embodiment, the ink is pumped using the following diaphragm pump.

A-2. The structure of the diaphragm pump of this example:
FIG. 3 is a cross-sectional view showing the structure of the diaphragm pump 100 of the present embodiment. As described above, the diaphragm pump 100 of this embodiment includes the upstream one-side valve 100u and the main body 10.
0b and the downstream one-side valve 100d are connected by an ink passage 42p.

The main body 100b is formed in a recess provided on the bottom surface side of the cartridge holder 42, and the diaphragm 102 provided so as to partition the inside of the recess and the opening, or by being partitioned by the diaphragm 102, And the shape memory alloy spring 104 for driving the diaphragm 102 and the like. The shape memory alloy spring 104, which will be described in detail later, is a special spring that functions as a simple spring at room temperature and has a property of returning to a previously memorized shape (memory shape) when heated. In the present embodiment, the shape memory alloy spring 104 employs a so-called string-wound spring. However, as long as the shape memory alloy spring 104 functions as a so-called spring, other types of springs such as a leaf spring may be used. Further, the shape memory alloy spring 104 of this embodiment is attached between the plate member 103 passed to the opening of the recess and the diaphragm 102.

The diaphragm 102 is a thin film-like member formed using an elastic material that does not pass a gas such as air or a liquid such as ink, and is elastically deformed by receiving an external force from one side of the thin film. . In addition, as a material of the diaphragm 102, a metal, rubber | gum, resin, etc. can be used, Furthermore, these materials can also be used in combination. In the present embodiment, the diaphragm 102 is formed of an elastic material, and is deformed when an external force is applied. When the external force is removed, the diaphragm 102 returns to its original shape by its own restoring force. May be formed of an inelastic material. In this case, an elastic member such as a spring may be provided in addition to the diaphragm 102 so that when the external force applied to the diaphragm 102 is removed, the diaphragm 102 returns to the original shape by the restoring force of the spring.

Two ink passages 42p are opened in the ink chamber 106, and one ink passage 42 is provided.
p is connected to the ink intake needle 46 through the upstream one-side valve 100u. The other ink passage 42p opens to the back surface of the cartridge holder 42 through the downstream one-side valve 100d, and is connected to the ejection head 20 through the ink tube 44 (see FIG. 1). The upstream one-side valve 100u and the downstream one-side valve 100d are one-way valves that are opened only when ink flows from the upstream side to the downstream side. Accordingly, when the ink tries to flow backward from the ink chamber 106 toward the ink intake needle 46, the upstream one-way valve 10.
0u is closed, and when the ink tries to flow backward from the ink tube 44 side (that is, the ejection head 20 side) to the ink chamber 106, the downstream one-side valve 100d is closed, and the reverse flow of the ink is prevented. It has become so.

Furthermore, in the diaphragm pump 100 of the present embodiment, the energizing portion 1 is connected to the shape memory alloy spring 104.
08 is connected, and it is possible to heat the shape memory alloy spring 104 by supplying an electric current. In addition, the operation of the energization unit 108 causing current to flow or cut off the shape memory alloy spring 104 is controlled by a control unit 90 provided in the inkjet printer 10.

As described above, the shape memory alloy spring 104 has a property of returning to a previously memorized shape (memory shape) when the temperature rises, and the diaphragm pump 100 of this embodiment is heated by being energized. The formed shape memory alloy spring 104 operates by using a force to return to the memory shape. For this reason, a negative pressure pump for operating the diaphragm pump becomes unnecessary, and it is possible to avoid an increase in the size of the inkjet printer 10. In addition, since the diaphragm pump 100 can be operated simply by energizing the shape memory alloy spring 104, even if the types of ink increase, it is possible to easily supply each ink to the ejection head 20. It becomes. Below, operation | movement of the diaphragm pump 100 of a present Example is demonstrated in detail.

B. Operation of the diaphragm pump of this embodiment:
As described above, the diaphragm pump 100 according to this embodiment is driven by using the force by which the shape memory alloy spring 104 heated by energization returns to the memory shape. Therefore,
As a preparation for explaining the operation of the diaphragm pump 100 of this embodiment, the shape memory alloy spring 1
The operation of 04 will be described.

FIG. 4 is an explanatory view showing the operation of the shape memory alloy spring 104. FIG. 4A shows a state in which both ends of a coiled spring (shape memory alloy spring) formed of a shape memory alloy are fixed to a jig. Here, it is assumed that the shape memory alloy spring is set on the jig in a state of being extended from the free length. In addition, in this shape memory alloy spring, it is assumed that a shape having a spring length shorter than the free length before being set on the jig is stored in advance. Then, the temperature of the shape memory alloy spring is gradually raised while measuring the force with which the spring is returning with a load meter.

FIG. 4B shows the reaction force (spring reaction force) of the shape memory alloy spring thus measured. As described above, since the shape memory alloy spring is set on the jig in a stretched state, first, a spring reaction force corresponding to the stretch amount is measured. When the temperature of the shape memory alloy spring is raised from this state, the shape memory alloy spring tries to return to the shape (memory shape) stored in advance. Here, since the memorized spring shape is shorter than the free length when it is set on the jig, a large spring reaction force appears in the load meter as the shape memory alloy spring attempts to return to the memorized shape. FIG. 4B shows a state where the spring reaction force suddenly increases near a certain temperature when the shape memory alloy spring is heated. When the temperature rises further, the shape memory alloy spring completely remembers the memorized shape (that is, the state is restored to the memorized shape if no external force is applied), and after that, it deforms in the same way as a normal spring. As long as the amount does not change, the spring reaction force is also constant.

As described above, as a shape memory alloy having a characteristic of returning to a previously memorized shape at a certain temperature or more, typically, Ni-Ti mainly containing nickel and titanium is used.
Alloys are known. In addition, the shape memory alloy is a temperature at which the shape of the alloy begins to recover to the memory shape depending on the alloy component ratio, the molding conditions when molding into a spring shape, and further the heat treatment conditions after molding,
It is possible to control various characteristics of the shape memory alloy, such as a restoration rate with respect to temperature, and a load difference between before and after restoration.

In the above description, the shape memory alloy spring is used in an extended state. As described above, when the shape memory alloy spring is used in the extended state, it is general to store a spring shape shorter than the free length and use it in the extended state from the free length.
In this way, the tensile force of the spring can be increased when the shape memory alloy spring attempts to return to its original short spring shape as the temperature rises.

In contrast, the shape memory alloy spring can be used in a compressed state. In this case, it is common to store a spring shape longer than the free length in the shape memory alloy spring. And in the state where temperature is low, like the normal spring, corresponding to the compression amount from the free length,
The spring reaction force in the tension direction can be obtained, but when the shape memory alloy spring tries to return to the original long spring shape as the temperature rises, it can be used to increase the tension force in the spring direction. Is possible.

Based on the description of the shape memory alloy spring as described above, the operation of the diaphragm pump 100 of the present embodiment will be described.

FIG. 5 is an explanatory diagram illustrating an operation in which the diaphragm pump 100 according to the present embodiment pumps ink toward the ejection head 20. FIG. 5A shows a state before the diaphragm pump 100 sucks ink. As shown in the figure, before sucking ink,
The switch of the energization unit 108 is in a disconnected state. For this reason, no current flows through the shape memory alloy spring 104, and the shape memory alloy spring 104 has substantially the same temperature as the ambient temperature of the inkjet printer 10. Further, as described above with reference to FIG. 4, since the spring reaction force of the shape memory alloy spring 104 is small when not heated, the shape memory alloy spring 104.
Is stretched by losing the restoring force of the diaphragm 102.

From this state, a current is passed through the shape memory alloy spring 104 by setting the switch of the energization unit 108 to a conductive state. Then, Joule heat is generated by the electric resistance of the shape memory alloy spring 104, and the temperature of the shape memory alloy spring 104 rises. As shown in FIG. 4B, when a certain temperature is reached, a large spring reaction force is generated as the shape memory alloy spring 104 tries to return to the short spring shape stored in advance. This large spring reaction force is larger than the restoring force of the diaphragm 102. As a result, the diaphragm 102 is deformed and the volume of the ink chamber 106 is increased.

Here, although two ink passages 42p are opened in the ink chamber 106, an upstream one-side valve 100u is provided in one ink passage 42p, and a downstream one-side valve 100d is provided in the other ink passage 42p. Is provided. Among these, the upstream side one-way valve 100u is the ink chamber 1.
The downstream one-way valve 100d is attached in a direction that blocks ink that is about to flow into the ink chamber 106. When the diaphragm 102 is deformed to increase the volume of the ink chamber 106, the two ink passages 42 p are depressurized, and a negative of ink that tries to flow into the ink chamber 106 is generated. However, the flow of ink from the downstream side is blocked by the downstream one-side valve 100d, and the ink taken in from the ink intake needle 46 flows into the ink chamber 106 through the upstream one-side valve 100u. . In FIG. 5B, a state in which the diaphragm 102 is deformed by energizing the shape memory alloy spring 104 is indicated by a white arrow. As a result, the state in which the ink taken in from the ink intake needle 46 flows into the ink chamber 106 via the upstream one-side valve 100u is indicated by a thick broken arrow.

As described above, the temperature at which the shape memory alloy spring 104 starts to recover to the memory shape, the recovery speed with respect to the temperature, the load difference before and after the recovery can be controlled by the alloy components, molding conditions, and heat treatment conditions. it can. Accordingly, if these conditions are set appropriately in advance, a short time (for example, around 1 second) from the start of energization without applying a large current to the shape memory alloy spring 104.
It is possible to complete the ink suction.

Here, the shape memory alloy spring 104 itself is heated by flowing an electric current, but the shape memory alloy spring 104 may be heated by flowing an electric current to the heater instead of the shape memory alloy spring 104. Even in this case, if the heater is attached to the shape memory alloy spring 104 or the heater is wound around the shape memory alloy spring 104, the shape memory alloy spring 104 can be efficiently heated. Moreover, since it is not necessary to form a heater with a shape memory alloy, it becomes possible to heat the shape memory alloy spring 104 more efficiently by adopting a material having better heater performance.

When ink is sucked into the ink chamber 106 as described above, energization to the shape memory alloy spring 104 is stopped. Then, the temperature of the shape memory alloy spring 104 gradually decreases due to the heat taken away by the surrounding air. As described above with reference to FIG. 4 (b), the shape memory alloy spring 104 becomes smaller in reaction force when the temperature is lowered, and eventually is stretched against the restoring force of the diaphragm 102. As a result, the volume of the ink chamber 106 tends to decrease.

Here, as described above, the upstream one-way valve 100 provided in the upstream ink passage 42p.
u is closed when ink is about to flow out (reverse flow) from the ink chamber 106, but the downstream one-way valve 100d provided in the downstream ink passage 42p passes the ink about to flow out of the ink chamber 106. Let For this reason, the ink in the ink chamber 106 is applied to the diaphragm 1.
02 is pumped to the ejection head 20 via the downstream one-way valve 100d by the force to return 02. In FIG. 5 (c), when the energization to the shape memory alloy spring 104 is stopped, the shape memory alloy spring 104 is cooled and the diaphragm 102 is restored to the original shape as indicated by the white arrow. Yes. As a result, a thick broken arrow indicates that the ink in the ink chamber 106 is pumped from the back side of the cartridge holder 42 toward the ejection head 20 via the downstream one-side valve 100d. .

Also, unlike the case where the shape memory alloy spring 104 is heated, the shape memory alloy spring 104
Therefore, the diaphragm 102 returns only to the original shape only slowly. Therefore, with the diaphragm pump 100 of this embodiment, it is difficult to pump a large amount of ink at a time. However, in practice, the diaphragm pump 100 only needs to pressure-feed the amount of ink ejected from the ejection nozzle. If this amount of ink is to be pumped, the diaphragm 102 is set to an appropriate size. It is possible to respond sufficiently.

Furthermore, although the ejection head 20 is provided with a plurality of ejection nozzles, it is rare that ink is ejected from all the ejection nozzles at the same time. In most cases, some of the ejection nozzles eject ink. Therefore, the amount of ink that is actually ejected is usually lower than the amount of ink that can be pumped by the diaphragm pump 100. Therefore, the ink chamber 106
The ink from the ejection head 20 to the ejection head 20 is in a state of being pressurized by the force with which the diaphragm 102 tries to return. For this reason, when ink is ejected from the ejection nozzle, it is possible to immediately supply ink to the ejection nozzle. In addition, even when a long time has passed without ink being ejected, air is mixed into the ink from the downstream side (the ink passage 42p, the ink tube 44, the ejection head 20, etc.) from the ink chamber 106. It is possible to avoid it.

As described above, the ink is gradually pumped by the amount ejected from the ejection nozzle. Further, as the ink is pumped, the diaphragm 102 returns to its original shape. Then, as shown in FIG. 5A, when the diaphragm 102 completely returns to its original shape, the shape memory alloy spring 104 is again energized to heat the shape memory alloy spring 104. Then, as shown in FIG. 5B, the diaphragm 102 is deformed, and the ink taken in from the ink intake needle 46 flows into the ink chamber 106. Thereafter, after the current flowing through the shape memory alloy spring 104 is cut, the ink can be pumped again.

The diaphragm pump 100 of the present embodiment repeats the above operation,
It is possible to pressure-feed ink corresponding to the amount ejected from the ejection nozzles to the ejection head 20. As described above, the diaphragm pump 100 according to the present embodiment can be operated simply by passing an electric current through the shape memory alloy spring 104 or by cutting it. Even if 100 must be installed, the inkjet printer 10 does not increase in size.

FIG. 6 is an explanatory diagram illustrating a conventional diaphragm pump 200 driven by negative pressure as a reference. As shown in the figure, in the conventional diaphragm pump 200, an air chamber 107 is provided on the opposite side of the ink chamber 106 with the diaphragm 102 interposed therebetween, and in this air chamber 107, a negative pressure pump 202, an open valve 204, Is connected. And the release valve 20
When the negative pressure pump 202 is driven with 4 closed, the inside of the air chamber 107 becomes negative pressure and the diaphragm 102 is deformed. As a result, the volume of the ink chamber 106 increases, and ink is sucked into the ink chamber 106 from the ink intake needle 46 through the upstream one-side valve 100u. In this manner, the negative pressure pump 202 is stopped while the ink is sucked into the ink chamber 106, and the release valve 20
4 is released. Then, since the pressure in the air chamber 107 returns to the atmospheric pressure, the diaphragm 102 deformed by the negative pressure tries to return to the original shape. This force is applied to the ink in the ink chamber 106, and the ink is pumped to the ejection head 20 through the downstream one-side valve 100d. Further, the negative pressure pump 202 and the release valve 204 are controlled by a control unit 90 mounted on the inkjet printer 10.

As is clear from comparison with the conventional diaphragm pump 200 shown in FIG. 6, in the diaphragm pump 100 of this embodiment described above with reference to FIG. 3, the negative pressure pump 202 and the release valve 204 are simply a shape memory alloy spring 104. The structure has been replaced with. Needless to say, the negative pressure pump 202, and even the release valve 204 is a bulky part compared to the shape memory alloy spring 104, so the negative pressure pump 202 and the release valve 204 are connected to the shape memory alloy spring 10.
By replacing it with 4, the entire diaphragm pump 100 can be greatly reduced in size.

Further, in the diaphragm pump 100 of the present embodiment, a portion where the air chamber 107 is formed in the conventional diaphragm pump 200 may be simply opened. For this reason, the structure of the diaphragm pump 100 itself can also be simplified. In addition, in order to operate the conventional diaphragm pump 200, the negative pressure pump 202 and the release valve 204 must be controlled, whereas in the diaphragm pump 100 of this embodiment, the shape memory alloy spring 104 is energized. It is only necessary to turn ON / OFF. For this reason, the inkjet printer 10
It is also possible to simplify the control content executed by the control unit 90 mounted on the.

As described above, the inkjet printer 10 has a plurality of colors (here, four colors).
In some cases, a plurality of inks are used, and the plurality of inks must be simultaneously pumped to the ejection head 20. In the case of the conventional diaphragm pump 200 that operates by negative pressure, a large negative pressure pump having a sufficient capacity is required so that all the diaphragm pumps 200 can be operated simultaneously. As the ink types increase, a larger capacity negative pressure pump is required. In order to mount a negative pressure pump with a large capacity, a large mounting space is required, and this has been an obstacle to miniaturization of the inkjet printer 10 mounted with various types of ink.

On the other hand, in the diaphragm pump 100 of the present embodiment, a plurality of diaphragm pumps 1
Even when 00 is operated simultaneously, the shape memory alloy springs 104 of the diaphragm pump 100 need only be energized simultaneously for a short time. For this reason, it is possible to easily realize the ink jet printer 10 having a small size while mounting various types of ink.

C. Modified example:
There are several variations of the diaphragm pump 100 of the present embodiment described above. Hereinafter, these modified examples will be briefly described.

C-1. First modification:
In the embodiment described above, when the shape memory alloy spring 104 is energized, the shape memory alloy spring 10
The diaphragm pump 10 uses the force that 4 is stored to shorten to the short spring shape.
It has been described that 0 is operated. On the other hand, it is also possible to store a long spring shape in the shape memory alloy spring 104 and operate the diaphragm pump 100 by using a force that the shape memory alloy spring 104 tries to expand when energized. .

FIG. 7 is an explanatory view showing a state in which the diaphragm pump 100 of the first modified example operates. FIG. 7A shows a state where the shape memory alloy spring 104 is not energized. When the current is not energized, the shape memory alloy spring 104 is cooled to a temperature substantially equal to that of the surrounding ink, so that only a weak spring reaction force is generated (see FIG. 4B). For this reason, the shape memory alloy spring 104 is in a state of being compressed by the diaphragm 102. However, when the shape memory alloy spring 104 is energized, the shape memory alloy spring 104 is warmed and attempts to return to the memory shape while deforming the diaphragm 102. As a result, the volume of the ink chamber 106 increases, and the ink taken from the ink intake needle 46 flows through the upstream one-side valve 100u. In FIG. 7B, a state in which the diaphragm 102 is deformed by the shape memory alloy spring 104 is represented by a white arrow, and a state in which ink flows into the ink chamber 106 through the upstream one-side valve 100u. Are represented by thick dashed arrows.

When ink is sucked into the ink chamber 106 in this way, the energization of the shape memory alloy spring 104 is stopped. Then, as the shape memory alloy spring 104 is cooled, the spring reaction force decreases and is gradually compressed by the diaphragm 102. As a result, the ink in the ink chamber 106 is pumped to the ejection head 20 through the downstream one-side valve 100d. In FIG. 7A, a state in which the diaphragm 102 is deformed in a direction of pressing and contracting the shape memory alloy spring 104 is represented by a white arrow. Along with this, the state in which the ink in the ink chamber 106 is pumped to the ejection head 20 via the downstream one-way valve 100d is represented by a thick broken arrow.

As described above, also in the diaphragm pump 100 of the first modified example that is used in a state where the shape memory alloy spring 104 is compressed, the ink from the ink intake needle 46 is energized by energizing the shape memory alloy spring 104. After the ink is sucked into the ink chamber 106, the current in the shape memory alloy spring 104 is stopped, so that the ink in the ink chamber 106 can be pressure-fed to the ejection head 20.

C-2. Second modification:
In the diaphragm pump 100 according to the above-described embodiment and the first modification, when the energization to the shape memory alloy spring 104 is stopped, the diaphragm 102 has its own restoring force as the reaction force of the shape memory alloy spring 104 decreases. It was described as being restored to its original shape. However, a spring (restoration spring) for restoring the diaphragm 102 to its original shape may be provided.

FIG. 8 is an explanatory view illustrating the diaphragm pump 100 of the second modified example provided with a restoring spring 109 that restores the diaphragm 102. In the illustrated example, a restoring spring 109 is provided in the ink chamber 106. When the shape memory alloy spring 104 is energized, the shape memory alloy spring 104 contracts and deforms the diaphragm 102. At this time, the restoring spring 109 is also pulled. It becomes the extended state. Accordingly, when energization to the shape memory alloy spring 104 is stopped and the temperature of the shape memory alloy spring 104 decreases, the restoring spring 109 tries to return the diaphragm 102 to its original shape. For this reason, even when a large amount of ink is ejected by the ejection head 20, the diaphragm 102 is quickly deformed by the force received from the restoring spring 109, and the ejected ink can be pumped.

In the example shown in FIG. 8, the restoring spring 109 is provided on the opposite side of the shape memory alloy spring 104 across the diaphragm 102. However, it is also possible to provide the restoring spring 109 on the same side as the shape memory alloy spring 104. For example, a restoring spring 109 having a smaller winding diameter than the shape memory alloy spring 104 is provided on the inner side of the shape memory alloy spring 104, or conversely, the outer diameter of the shape memory alloy spring 104 is larger than that of the shape memory alloy spring 104. If a large restoring spring 109 is provided, it is possible to mount the restoring spring 109 without changing the size of the diaphragm pump 100.

Although various embodiments have been described above, the present invention is not limited to all the above embodiments, and can be implemented in various modes without departing from the scope of the invention.

2 ... Print medium, 10 ... Inkjet printer, 11 ... Front cover,
12 ... paper discharge port, 13 ... paper feed tray, 14 ... top cover,
15 ... operation buttons, 20 ... jetting head, 30 ... drive mechanism,
32 ... Timing belt 34 ... Drive motor 40 ... Ink cartridge
42 ... cartridge holder, 42p ... ink passage, 44 ... ink tube,
46 ... Ink intake needle, 50 ... Cap member, 90 ... Control unit,
100 ... Diaphragm pump, 100b ... Main body, 100d ... Downstream one-side valve,
100u ... Upstream one-side valve, 102 ... Diaphragm, 103 ... Plate member,
104 ... shape memory alloy spring, 106 ... ink chamber, 107 ... air chamber,
108 ... Current-carrying part, 109 ... Restoration spring, 200 ... Diaphragm pump,
202 ... Negative pressure pump, 204 ... Opening valve

Claims (5)

A diaphragm pump that sucks liquid from the first passage and pumps it from the second passage,
A liquid chamber connected between the first passage and the second passage and having a volume changed by deformation of the diaphragm;
A first one-way valve provided in the first passage, which allows the liquid to flow into the liquid chamber from the first passage, but does not allow the liquid chamber to flow into the first passage. When,
A second one-way valve provided in the second passage, which allows the liquid to flow out from the liquid chamber to the second passage, but does not allow the liquid passage from the second passage to the liquid chamber. When,
A diaphragm deforming means for deforming the diaphragm;
The diaphragm deformation means includes:
A shape memory alloy spring that is deformed by an external force received from the diaphragm side at a predetermined temperature or lower, and that returns to an initial shape stored in advance when the temperature rises above the predetermined temperature;
A diaphragm pump comprising: heating means for heating the shape memory alloy spring to the predetermined temperature or higher. The diaphragm pump according to claim 1,
The diaphragm pump is a diaphragm pump which is means for heating the shape memory alloy spring to the predetermined temperature or more by energizing the shape memory alloy spring. The diaphragm pump according to claim 1 or 2, wherein
The shape memory alloy spring is a diaphragm pump that is a spring that deforms the diaphragm in a direction in which the volume of the liquid chamber increases when the shape memory alloy spring returns to the initial shape. The diaphragm pump according to any one of claims 1 to 3,
A diaphragm pump comprising a restoring spring that is deformed together with the diaphragm by the shape memory alloy spring and generates a reaction force in a direction to restore the deformed diaphragm. A liquid ejecting apparatus that ejects liquid in a container from an ejection nozzle,
The liquid injection apparatus which supplies the liquid in the said container to the said injection nozzle using the diaphragm pump as described in any one of Claims 1 thru | or 4.

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