JP3104491B2 - Ink supply mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink supply mechanism for supplying ink to a recording head in an ink jet recording apparatus.

[0002]

2. Description of the Related Art Conventionally, as an ink supply mechanism used in an ink jet recording apparatus, an ink absorber such as felt or sponge or a fibrous material is loaded in an entire area of an ink tank connected to an ink jet head. There is known an ink absorber in which ink is impregnated and held in advance, and ink in the ink absorber is supplied to a recording head.

However, in the ink supply mechanism having such a configuration, since the ink is held by the capillary force of the ink absorber, only about 40% to 60% of the ink volume in the ink tank can be used. , Low usage efficiency. Therefore, if an attempt is made to extend the service life of the ink tank, the size of the ink tank is inevitably increased, and a technical problem has arisen in that the demand for downsizing is not met. Further, as the amount of ink held by the ink absorber decreases as the ink is consumed, the negative pressure acting on the ink impregnated in the ink absorber increases due to the decrease in the ink head pressure, and the ink applied to the recording head A problem arises that supply of water is obstructed. When this phenomenon becomes remarkable, the ink ejection operation is performed in a state where ink is not supplied to the recording head.
There is a technical problem that air bubbles flow backward from the print nozzle portion in the recording head and cause image quality defects.

As an ink supply mechanism for solving such a technical problem, for example, as described in Japanese Patent Application Laid-Open No. 62-231759, a closed ink tank is filled only with ink, In some printers, a pressure control valve is provided between a tank and a printhead to supply ink to the printhead at a constant pressure.

In an ink supply mechanism provided with such a pressure control valve, it is very difficult to actually create a control valve that opens and closes by the action of a slight negative pressure. There was a problem that it would. Also,
If the control valve is not used for a long period of time, there is a problem that the ink sticks to the control valve portion and the control valve does not open and close, and the reliability for long-term use is low.

[0006] For example, in Japanese Patent Application Laid-Open No. 1-148559, a closed ink tank is filled only with ink, and a capillary channel and an overflow reservoir are provided to maintain a constant negative pressure in the ink tank. Already provided.

[0007] According to the ink supply mechanism combining the capillary flow path and the overflow reservoir, in the initial stage of printing, ink in the ink tank is consumed, and when the negative pressure in the ink tank increases, air flows through the capillary. The ink is introduced into the ink tank, the negative pressure value in the ink tank is kept substantially constant, and the ink in the ink tank is stably supplied to the recording head. However, when the surrounding environment changes and, for example, air existing in the upper space in the ink tank expands,
The ink in the ink tank moves to the overflow reservoir through the capillary tube, and the ink in the ink tank temporarily retreats to the overflow reservoir. For this reason, a positive pressure is generated in the printhead only at the level difference between the free surface formed by the ink in the overflow pool and the printhead portion. In such a state, if the head surface is slightly dirty,
A trouble of causing ink leakage from the nozzle occurred, and the reliability was lacking. Further, since the overflow reservoir is connected to the sealed ink tank via a considerably long capillary, the device configuration becomes complicated, for example, the capillary is bent appropriately. Furthermore, even if the negative pressure value in the ink tank increases with the consumption of ink in the ink tank, the introduction of air bubbles from the capillary tube becomes uncertain if dust or dry ink is clogged in the capillary tube. . As a result, the negative pressure value in the ink tank tends to be unstable, and there has been a technical problem that it is difficult to supply ink to the head stably.

As another ink supply mechanism, for example, Japanese Patent Application Laid-Open No. 4-296566 discloses a method in which a bag-like body provided in an ink tank is filled only with ink and a hole is provided in a lower part of the ink tank. Describes that the inside of the ink tank is maintained at a certain range of negative pressure. But,
With this configuration, if the surrounding environment changes significantly and an accident occurs that exceeds the pressure adjustment function of the bag-shaped body, the pressure inside the ink tank relatively exceeds the atmospheric pressure or the atmospheric pressure, and the ink tank A situation in which a large amount of ink leaks through the lower hole occurs, and in severe cases, the ink may adhere to a contact portion with the printer or the like, resulting in a failure of the printer. When the ink tank is removed from the printer and left, the ink tank is left in various postures.
In such a case, when the ink is not in contact with the hole at the bottom of the ink tank, the ink attached to the bubble generator is solidified, and troubles such as the bubble generation operation not being performed by the hole occur. .

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and increases the ink storage efficiency while satisfying the demands for simplification and downsizing of the structure. It is an object of the present invention to provide an ink supply mechanism of an ink jet recording apparatus which can improve the supply property and can surely suppress the influence of a change in the surrounding environment regardless of the posture of the printer when the printer is mounted. Things.

[0010]

According to the present invention, there is provided an ink supply mechanism in an ink jet recording apparatus for supplying ink to a recording head for recording, wherein the ink is contained and a part of a peripheral inner wall is formed of an elastic film. Ink chamber, a meniscus forming member provided with a small hole in a part of a wall above the ink chamber, and a liquid guiding portion for supplying liquid to the meniscus forming member, and the liquid is supplied by the liquid guiding portion. The pressure in the ink chamber is adjusted by the meniscus formed in the micropores of the meniscus forming member by the liquid and the elasticity of the film. The liquid guide section is configured as an ink supply body that contacts the surface of the meniscus forming member on the ink chamber side, and extends into the ink, and supplies the ink in the ink chamber to the meniscus forming member. can do.

[0011]

According to the present invention, the liquid is always supplied to the meniscus forming member provided on a part of the wall above the ink chamber by the liquid guiding portion, and the liquid is supplied to the minute holes of the meniscus forming member. Is formed. When the ink is consumed or the pressure in the ink chamber relatively decreases due to a change in the surrounding environment, the elastic film provided on a part of the inner wall around the ink chamber is protruded toward the inside of the ink tank. Overhang in the state of. When the pressure in the ink chamber further decreases, the meniscus formed on the meniscus forming member is pushed by the air, and air enters the ink chamber, forming bubbles, increasing the volume in the ink chamber and increasing the pressure in the ink chamber. . After the generation of air bubbles,
A liquid film is formed again in the micropores of the meniscus forming portion, and the pressure balance by the meniscus is maintained.

When the surrounding environment changes and the pressure in the ink chamber relatively increases, the elastic film provided on a part of the inner wall around the ink chamber gradually changes from a state of being convex toward the inside of the ink chamber. , The negative pressure value inside the ink tank is kept in a certain range.

[0013] Further, ink is used as the liquid supplied by the liquid guiding section, ink in the ink chamber is sucked up by the liquid guiding section, and supplied to the meniscus forming section, so that a special liquid for forming a meniscus is not used. In both cases, the meniscus forming portion can be always kept wet.

[0014]

FIG. 1 is a sectional view showing a first embodiment of the ink supply mechanism of the present invention. In the figure, 1 is an ink tank, 2
Denotes an ink supply body, 3 denotes an ink meniscus forming body, 4 denotes an elastic film, 5 denotes a filter, 6 denotes a recording head, 7 denotes a manifold, and 8 denotes an air communication port. This embodiment shows an example in which the ink tank 1 and the recording head 6 are formed integrally.

The housing of the ink tank 1 is made of a material having good ink resistance so as to have rigidity and to hold ink for a long period of time. An elastic film 4 is provided on a side wall in the ink tank 1. An atmosphere communication port 8 is provided in a side wall of the ink tank 1, and is configured so that the atmosphere can enter between the elastic body film 4 and the side wall of the ink tank 1 by deformation of the elastic body film 4. . The ink is contained in the elastic film 4 of the ink tank 1.

At the top of the ink tank 1, an ink meniscus forming body 3 having a large number of minute holes is provided.
A meniscus of ink is formed in the minute holes of the ink meniscus forming body 3. The negative pressure in the ink tank 1 is adjusted by the surface tension of the ink at the meniscus. As the ink meniscus forming body 3, for example, a mesh body such as a wire net or a resin net, a porous body such as a felt or a sponge, a fibrous material having a one-dimensional or two-dimensional structure, a nonwoven fabric material, or the like is used. be able to. As a specific example of the mesh-like body, a metal mesh filter, a metal fiber, for example, a SUS fine wire is made into a felt shape, and further, a filter having a base material obtained by compression sintering, an electroforming metal filter, or the like is used. be able to. Also,
A filter made of a knitted resin fiber, a filter having a high-definition hole diameter by laser beam processing, electron beam processing, or the like, a pipe having a high-definition hole diameter, or the like can be used. For example, a mesh filter having a filtration accuracy of 70 μm can be used. The shape of the ink meniscus forming body 3 can be a disk shape, a rectangular shape, or a shape capable of securing a certain area, and there is considerable design freedom.

An ink supply 2 is provided on the lower surface of the ink meniscus forming body 3. The ink supply 2 extends into the ink in the ink tank 1, and is desirably provided until it contacts the bottom surface of the ink tank 1, and is configured to always contact the ink. The ink supply unit 2 supplies ink to the ink meniscus forming unit 3 by capillary force. Thus, the ink meniscus is always formed in the micropores of the ink meniscus forming body 3. As the ink supply 2, for example, polyester fiber 1
Dimensionally spun polyester felt can be used. In addition, various materials such as polyurethane, melamine foam, and other porous materials, two-dimensional and three-dimensional fiber structures, and non-woven fabric materials can be used as long as the material has an appropriate capillary force with ink and is resistant to ink. Can be used. Also, the shape may be various shapes such as a cylindrical shape, a quadrangular prism, and a triangular prism as long as the cross-sectional area can be secured to some extent. Also, the cross-sectional dimension of the ink supply 2 is smaller than the opening dimension of the ink meniscus forming body 3. Thereby, a gap can be provided around the ink supply body 2, and a portion of the ink meniscus formation body 3 where bubbles are generated is secured.

A recording head 6 is provided on the bottom of the ink tank 1.
A manifold 7 is provided for communicating with the manifold. Further, a filter 5 is provided at a connection portion between the ink tank 1 and the manifold 7, and collects foreign matters such as dust and bubbles in the ink. As the filter 5, for example, a filtration accuracy 2
Those having a thickness of 0 μm are used. The filtering accuracy is determined based on the idea that foreign matters larger than the ink flow path diameter in the recording head 6 are trapped. A large number of nozzles (not shown) are formed in the recording head 6 at a high density. For example, 128 nozzles can be formed at a density of 300 spi. Each of the nozzles is provided with a heating element (not shown) for generating air bubbles by energization and ejecting ink droplets. In FIG. 1, the ejection of ink droplets is performed downward. Around the recording head 6, there are also a heat sink to which the recording head 6 itself is attached, a printed wiring board for supplying an electric signal to the recording head 6, and the like.

FIG. 2 is an explanatory diagram of the operation of the ink supply mechanism according to the first embodiment of the present invention. The reference numerals in FIG.
Is the same as At the time of factory shipment, after the ink is filled in the ink tank 1 and priming is performed from the recording head 6, an airtight seal is attached to the nozzle portion of the recording head 6, the air communication port 8, and the ink meniscus forming body 3, Packaged. In this state, the ink negative pressure value in the recording head 6 is, for example, 20 mmH _2.
O. At this time, the elastic film 4 on the inner wall of the ink tank 1 is pushed by the atmospheric pressure from the air communication port 8 provided in the ink tank 1 and is in a state of being convex toward the inside of the ink tank 1. Further, ink is supplied to the ink meniscus forming body 3 by the ink supply body 2, and the inside of the ink tank 1 is shut off from the atmosphere by the meniscus of the ink formed in the minute holes of the ink meniscus forming body 3.

When the printer is mounted and printing starts with the recording head 6, the negative pressure in the ink tank 1 gradually increases. Accordingly, as shown in FIG. 2 (A), the elastic film 4 protrudes toward the inside of the ink tank in an increasingly convex state against the tension. When the negative pressure value in the ink tank 1 exceeds a certain value, the micro meniscus of the ink formed on the ink meniscus forming body 3 generates bubbles in the form of soap bubbles toward the inside of the ink tank, and eventually bursts. Then, air is introduced into the ink tank. This operation is repeated, and the ink tank 1
An increase in the internal negative pressure value is suppressed, and the negative pressure in the ink tank 1 is kept constant. After the rupture of the bubbles, a meniscus is formed again by the ink, and the inside of the ink tank 1 is not released to the atmosphere.

During printing, the negative pressure value of the recording head 6 becomes -12.
It has been found that, when it exceeds 5 mmH ₂ O, refilling of ink is hindered, the amount of ink droplets ejected from the recording head 6 decreases, and the print quality called blurring is reduced. In the first embodiment shown in FIG. 1, only the ink head pressure of the ink tank 1 having a high / low difference is determined.
There is no change in the pressure on. Further, since the pressure loss caused by the resistance component in the ink supply mechanism during printing is about 30 mmH ₂ O during solid printing, the recording head pressure Phead in the worst state where there is almost no remaining ink is provided.
Can be calculated as follows: Head = −20 mm H ₂ O (initial negative pressure) −50 mm
H ₂ O (ink tank height difference) -30mmH ₂ O (pressure _{loss) = -100mmH 2 O> -125mmH 2} O Thus, the recording head pressure Phea in worst case
d is greater than -125mmH ₂ O, does not occur blur, ink remaining amount, it is possible to also satisfactory printing in any state printing coverage.

As printing proceeds, the amount of ink inside the ink tank 1 decreases and is replaced by air, and the ink tank 1 becomes more susceptible to changes in the surrounding environment. That is, the air introduced into the ink tank 1 expands or contracts due to a change in ambient temperature. Further, the pressure of the air in the ink tank 1 relatively increases or decreases due to the change in the atmospheric pressure.

The surrounding environment changes while air is introduced into the ink tank 1, and for example, the ambient temperature decreases or the atmospheric pressure increases, and the pressure in the ink tank 1 relatively decreases. When the ink is consumed, the micro meniscus of the ink formed on the ink meniscus forming body 3 expands like a soap bubble toward the inside of the ink tank and repeats the destruction as in the case where the ink is consumed. This allows
Air is introduced into the ink tank 1 to reduce a decrease in the pressure inside the ink tank 1 and the negative pressure value inside the ink tank 1 is kept constant.

When the ambient environment changes and, for example, the ambient temperature rises or the atmospheric pressure decreases and the pressure in the ink tank 1 relatively increases, FIG.
As shown in (B), the elastic film 4 which protrudes in a convex state toward the inside of the ink tank 1 gradually decreases its convex state due to its tension, and the internal volume of the ink tank 1 becomes smaller. Since the pressure increases, the increase in the pressure inside the ink tank 1 is suppressed, and the negative pressure value inside the ink tank 1 is kept within a certain range.

If the surrounding environment changes greatly and an accident occurs in which the increase in pressure cannot be suppressed only by increasing the internal volume of the ink tank 1 due to the decrease in the convex state of the elastic film 4, The pressure inside the ink tank 1 may be higher than the atmospheric pressure. In such a case, since the ink meniscus forming body 3 is provided on the upper portion of the ink tank, the ink does not leak from the ink meniscus forming body 3, and the ink leak occurs from the recording head 6 in the capping state. Therefore, since the ink leak is absorbed by the waste ink absorber provided in the cap, the printer body is not contaminated with the leaked ink, which does not cause a failure.

FIG. 3 is an explanatory view of the operation principle of the ink meniscus forming body 3. In the figure, 3 is an ink meniscus forming body, 11 is ink, and 12 is a hole. As described above, the ink meniscus forming body 3 is provided with the minute holes 12. Although only one hole 12 is shown in FIG. 3, a plurality of holes 12 may exist. The ink 11 supplied to the ink meniscus forming body 3 by the ink supplying body 2 of FIG.
An ink film is formed in the hole 12. When the same pressure is applied to both surfaces of the ink meniscus forming body 3, as shown in FIG. 3 (A), the ink film formed in the hole 12 becomes a meniscus somewhat concaved in the hole. .

FIG. 3B shows a state in which the ink meniscus forming body 3 is mounted in the ink chamber and the balance between the negative pressure in the ink chamber and the atmospheric pressure is maintained. In FIG. 3B,
The upper side shows the atmospheric pressure, and the lower side shows the ink chamber. When the ink contained in the ink chamber is consumed and the pressure in the ink chamber becomes negative compared with the atmospheric pressure, the film of the ink 11 formed in the hole 12 is pushed from the atmosphere side to the ink chamber side, and the ink 11 Has a convex shape toward the ink chamber. At this time, due to the surface tension of the ink 11, a force for returning the meniscus to the original, that is, a force toward the atmosphere is generated, and the ink 11 is brought into an equilibrium state.

Now, the atmospheric pressure is Pair, the pressure in the ink chamber is Ptank, and γ is the ink 11 and the ink meniscus forming body 3.
Where ρ is the density of the ink, θ1 is the wetting angle on the air side, θ2 is the wetting angle on the ink chamber side, D is the diameter of the hole 12, and g is the gravitational acceleration.
P1 = 4γ · cos θ1 / D + 4γ · cos θ2 / D Here, when approximating θ1 = θ2 = θ, P1 = 8γ · cosθ / D Further, the pressure difference P2 at the interface is P2 = Pair−Ptank In an equilibrium state, Since P1 = P2, Ptank = Pair-8γ · cos θ / D.

As can be seen from this equation, the balance is made in a state where cos θ is increased according to the negative pressure in the ink chamber. That is, as the negative pressure in the ink chamber increases, the convex shape of the ink toward the ink chamber gradually increases.
(C), (D), and (E). When the negative pressure in the ink chamber further increases, as shown in FIG. 3 (F), an ink film is formed again at the hole 12 and the convex portion becomes foamy. Due to the bubbles, the volume in the ink chamber is increased by the air in the bubbles, and the negative pressure in the ink chamber is reduced. In this way, the negative pressure in the ink chamber is always
It is kept almost constant.

As the ink in the ink chamber is consumed, the generation of such bubbles is repeated. As shown in FIG. 3 (G), the sequentially generated bubbles become larger by being combined with the previously generated bubbles and the bubbles generated from nearby holes, become unstable, and eventually burst.

When the ink in the ink tank has been consumed to a certain extent, the ink tank may be detached from the printer and left alone. In such a case, it is not known what position the ink tank is placed in. Also in the first embodiment shown in FIG. 1 described above, by extending the ink supply body 2 to the bottom of the ink tank 1, when a certain degree of inclination or half or more of the ink remains, No matter what direction the ink supply body 2 is left, the ink supply body 2 comes into contact with the ink, so that the ink supply body 2 supplies the ink to the ink meniscus forming member 3 formed on the upper portion of the ink tank. There is no possibility that the meniscus dries and the ink is transformed. Therefore, a good ink meniscus is formed even when left unattended,
The negative pressure in the ink tank is always controlled to a good value. However, when the remaining amount of the ink is small, in the configuration shown in FIG. 1, a state where the ink does not touch the ink supply body 2 may occur. In this case, the ink meniscus is destroyed and the ink inside the ink tank 1 is damaged. Pressure will be released to the atmosphere.

To prevent such a problem, several modifications are conceivable. FIGS. 4 to 6 are cross-sectional views showing a modification of the first embodiment of the ink supply mechanism of the present invention. In the figure, the same parts as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted. Reference numerals 9 and 10 denote ink supply branch portions. The ink supply mechanism shown in FIG.
Are installed so as to enclose the inner surface of the ink tank 1. According to such a configuration, even if the ink tank 1 is removed from the printer and held in any posture,
The ink supply 2 is always in contact with the ink. Therefore, ink is always supplied to the ink meniscus forming body 3, and the ink meniscus formed on the ink meniscus forming body 3 is kept in a good state. Therefore, the ink meniscus is not broken and the pressure in the ink tank 1 is not released to the atmosphere. In addition, it is possible to cope with environmental fluctuations such as an increase in the outside air temperature, a decrease in the outside air pressure, a decrease in the outside air temperature, and an increase in the outside air pressure, and a substantially constant negative pressure can be maintained. When installing the ink supply body 2, it is necessary not to affect the operation of the elastic film 4.

In the ink supply mechanism shown in FIG. 5, the ink supply 2 is provided with an ink supply branch 9 extending to each corner of the ink tank 1. Thus, even if the ink tank 1 is detached from the printer and held in any posture, the ink supply 2 or a part of the ink supply branch 9 always contacts the ink. 4, the ink is always supplied to the ink meniscus forming body 3 and the ink meniscus formed on the ink meniscus forming body 3 is kept in a good state. The pressure in the tank 1 is not released to the atmosphere. Further, it is possible to cope with environmental fluctuations such as an increase in outside air temperature or a decrease in outside air pressure, or a decrease in outside air temperature or an increase in outside air pressure, and it is possible to maintain a substantially constant negative pressure.

The ink supply mechanism shown in FIG. 6 is provided with an ink supply branching portion 10 that floats in the ink in the ink tank 1 around the ink supply 2. Thus, even if the ink tank 1 is detached from the printer and held in any posture, the ink supply branching portion 10 moves with the movement of the ink and always comes into contact with the ink. Therefore, similarly to the modification of FIG. 4, the ink meniscus forming body 3
Is always supplied and the ink meniscus formed on the ink meniscus forming body 3 is kept in a good state, so that the ink meniscus is not broken and the pressure in the ink tank 1 is not released to the atmosphere. In addition, it is possible to respond to environmental fluctuations such as an increase in outside air temperature, or a decrease in outside air pressure or a decrease in outside air temperature, or an increase in outside air pressure,
An almost constant negative pressure can be maintained.

A first embodiment of the above-described ink supply mechanism is as follows.
Various modifications other than the above-described modification of the ink supply body are possible. FIG. 7 is a perspective view of an example of an ink supply mechanism having a cylindrical ink tank. The ink supply mechanism may be configured to have a cylindrical ink tank 1 as shown in FIG. 7 in addition to the configuration having a rectangular parallelepiped ink tank. As described above, the shape of the ink tank can be realized in various forms, and can be designed according to the printer to be mounted.

In the above-described embodiment, one ink meniscus forming member and one ink supplying member are provided. For example, a plurality of sets of the ink meniscus forming member and the ink supplying member may be arranged, or the meniscus forming portion may be provided. And increase
It is also possible to adopt a configuration in which a plurality of ink supplies are connected.

In the above embodiment, the liquid for forming a meniscus in the ink meniscus forming body 3 is
Although an example in which the ink in the ink tank 1 is used is shown, other liquids can be used. For example, when the ink supply mechanism is mounted on the printer, the liquid can be supplied to the ink meniscus forming body 3 by the liquid supply mechanism of the printer. As the liquid, a separately prepared liquid can be used, or the ink in the waste ink tank can be used. However, the configuration using the ink in the ink tank 1 as in the above-described embodiment can easily realize the above-described operation.

The above-described ink supply mechanism is detachably attached to the printer, but may be fixed to the printer. Further, in the above-described embodiment, the ink supply mechanism integrated with the recording head has been described. At this time, only the ink tank may be replaceable, or the recording head may be replaceable. The ink ejection direction is downward,
It can be sideways.

FIG. 8 is a sectional view showing a second embodiment of the ink supply mechanism of the present invention. In the figure, the same parts as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted. 21 is an ink absorber chamber, 22 is an ink absorber, 23 is an air communication port, 24
Is a main ink chamber. In this embodiment, the ink tank 1
Is provided with an ink absorber chamber 21 above. In the lower part of the ink tank 1, there is a main ink chamber 24 whose side wall is formed by the elastic film 4, as in the first embodiment.

An ink absorber 22 is provided in the ink absorber chamber 21. As the material of the ink absorber 22, a fibrous material having a two-dimensional structure, a porous material having a three-dimensional structure, a felt obtained by spinning the fibrous material three-dimensionally, a nonwoven fabric material, and the like can be used. Specifically, for example, a batting material in which polyester fibers are bundled in one direction can be used. Of course, other materials may be used.

The ink absorber chamber 21 is provided with an air communication port 23. The ink absorber 22 communicates with the atmosphere through the atmosphere communication port 23 and is released from the atmosphere. The ink in the ink absorber 22 is pressed by the atmospheric pressure and is drawn out from below the ink absorber 22 by the negative pressure toward the main ink chamber 24, so that the ink in the ink absorber 22 can be used efficiently. . At this time, the negative pressure in the main ink chamber 24 is kept constant by the capillary force of the ink absorber 22 and the tension of the elastic film 4 in the main ink chamber 24. It is also possible to provide a sheet that does not allow ink to pass through and allows air to pass through the air communication port 23 so that the ink does not fly out from the air communication port 23. Alternatively, the air communication port 23 may be configured by arranging a large number of fine holes from which ink does not flow. The periphery of the ink absorber 22 is inserted in close contact with the inner wall of the ink absorber chamber 6. The purpose of this is to prevent air introduced from the atmosphere communication port 23 from entering along the inner wall of the ink absorber chamber 21.

The ink meniscus forming body 3 is arranged so as to be in contact with the ink absorbing body 22 provided in the ink absorbing body chamber 21. The ink absorber 22 can be configured to be disposed at a position slightly higher than the bottom surface of the ink absorber chamber 21. Thereby, the ink absorber 2
Even if the air reaches the bottom surface of the ink absorber chamber 21 through the side surface of the second ink container 2, the air prevents the surface of the ink meniscus forming body 3 from being covered. Thus, the ink held in the ink absorber 22 is efficiently supplied to the main ink chamber 24 via the ink meniscus forming body 3.

The filter 5 includes the ink meniscus forming body 3
It is configured to have a higher filtration accuracy than the filtration accuracy of the micropores. This makes it possible to filter dust and the like in the ink in the main ink chamber 24. Although the filter prevents pressure propagation as a resistance to instantaneous pressure changes, the ink pressure becomes the same value over a long period of time.

The operation of the second embodiment of the ink supply mechanism of the present invention will be described. When not used, the main ink chamber 24 and the ink absorber 22 of the ink absorber chamber 21 are filled with an amount of ink that can be absorbed. In this state, the recording head 6 is maintained at a negative pressure due to the capillary force of the ink absorber 22 and the tension of the elastic film 4.

When recording is started and ink is consumed in the recording head 6, the ink contained in the ink absorber 22 is released via the ink meniscus forming member 3 by the negative pressure generated at that time. Move to 24. At this time, since both sides of the ink meniscus forming body 3 are ink, no bubble is generated.

When the ink consumption further proceeds and the ink contained in the ink absorber 22 runs out, the surface of the ink meniscus forming body 3 on the ink absorber chamber 21 side is released to the atmosphere. When the ink is further consumed, the first
As described in the embodiment, the ink meniscus forming body 3
Due to the meniscus of the ink formed in the main ink chamber 2
The negative pressure in 4 is kept almost constant. This operation continues until the ink supply 2 separates from the ink. Ink supply 2
Is extended to the bottom of the main ink chamber 24, the negative pressure control operation is continued until the ink is almost exhausted.

The operation when the surrounding environment changes will be described. First, when the main ink chamber 24 is fully filled with ink and the ink is present in the ink absorber chamber 21, the influence of the surrounding environment change is not so large. Ink absorber 22 and recording head 2 in ink absorber chamber 21
8, the same atmospheric pressure is applied, so that even if the surrounding environment changes, no differential pressure is generated.

Next, consider a case where there is no ink in the ink absorber chamber 21 and an air layer exists in the main ink chamber 24. At this time, when the temperature rises or the atmospheric pressure decreases, the air in the main ink chamber 24 relatively expands.
In this case, similar to the first embodiment, the main ink chamber 2
The elastic film 4 which protrudes in a convex state toward the inside of 4 gradually decreases its convex state due to its tension. As a result, the internal volume of the main ink chamber 24 increases, so that an increase in the pressure in the main ink chamber 24 is suppressed, and the negative pressure value inside the ink tank 1 is kept within a certain range. When the convex state of the elastic film 4 is reduced to some extent, the increase in the pressure in the main ink chamber 24 due to the tension gradually becomes impossible. At the same time, due to the interfacial tension of the meniscus with the ink absorber 22, the ink supply 2
Is sucked up through the ink, and the ink is absorbed by the ink absorber 22. Since the volume in the main ink chamber 24 is reduced by the amount of ink absorbed by the ink absorber 22, an increase in pressure due to expansion of air can be prevented. Due to the difference between the recording head nozzle diameter and the filtration diameter of the ink meniscus forming body 3, the ink always breaks the meniscus of the ink meniscus forming body 3 and is absorbed by the ink absorber 22. Thereafter, when the air in the main ink chamber 24 contracts or the ink is consumed, the pressure is controlled by the increase of the convex state of the elastic film 4 and the capillary force of the ink absorber 22, and The ink absorbed by the ink absorber 22 moves to the main ink chamber 24 and is consumed.

When the air temperature decreases or the atmospheric pressure increases and the air in the main ink chamber 24 relatively contracts, the main ink chamber 24 operates in the same manner as when the ink is consumed. The internal pressure will be adjusted.

As described above, the ink supply mechanism shown in FIG. 8 operates in response to environmental changes that cannot be handled by the ink supply mechanism shown in FIG.
The ink can always be supplied to the recording head at a substantially constant pressure without causing ink leakage from the recording head 6. Further, even when detached from the printer, the air communication port 2 is not affected by the capillary force of the ink absorber 22.
3, no negative pressure can be maintained at all times as in the first embodiment.

In the above-described second embodiment, various modifications are possible as in the first embodiment. For example, the ink supply body 2 can have a shape as shown in FIGS. 4 to 6, and the shape of the ink tank 1 can be various shapes such as a cylindrical shape in addition to a rectangular parallelepiped shape. . In addition, a plurality of ink meniscus forming bodies and ink supply bodies can be provided. In this case, air enters between the wall of the ink absorbing chamber and the ink absorbing body, and the space between the ink absorbing body and the ink meniscus forming body. A layer of air is formed on
The ink contained in the ink absorber is prevented from remaining, and the ink can be used efficiently. Further, the recording head and the ink tank can be configured as separate bodies, and the direction of ink ejection from the recording head can be horizontal, in addition to downward.

[0052]

As is apparent from the above description, according to the present invention, the negative pressure inside the ink tank can be kept substantially constant by the elastic film and the meniscus forming member, and the ink acting on the recording head can be maintained. There is an effect that it is possible to provide a highly reliable and highly efficient ink supply mechanism of an ink jet recording apparatus by keeping the pressure fluctuation within an appropriate value range, suppressing the influence of a change in the surrounding environment, and providing a highly reliable and efficient ink supply mechanism.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first embodiment of an ink supply mechanism of the present invention.

FIG. 2 is an explanatory diagram of an operation in a first embodiment of the ink supply mechanism of the present invention.

FIG. 3 is an explanatory diagram of an operation principle of the ink meniscus forming body 3.

FIG. 4 is a sectional view showing a modification of the first embodiment of the ink supply mechanism of the present invention.

FIG. 5 is a sectional view showing another modification of the first embodiment of the ink supply mechanism of the present invention.

FIG. 6 is a sectional view showing still another modified example of the first embodiment of the ink supply mechanism of the present invention.

FIG. 7 is a perspective view of an example of an ink supply mechanism having a cylindrical ink tank.

FIG. 8 is a sectional view showing a second embodiment of the ink supply mechanism of the present invention.

[Explanation of symbols]

Reference Signs List 1 ink tank, 2 ink supply body, 3 ink meniscus forming body, 4 elastic film, 5 filter, 6 recording head, 7 manifold, 8 atmosphere communication port, 9, 10
Ink supply branch, 11 ink, 12 holes, 21
Ink absorber chamber, 22 ink absorber, 23 atmosphere communication port, 24 main ink chamber.

Claims (2)

(57) [Claims] 1. An ink supply mechanism in an ink jet recording apparatus for supplying ink to a recording head to perform recording, wherein an ink chamber containing ink and a part of a peripheral inner wall is formed of a film having elasticity; A meniscus forming member provided on a part of the upper wall and having a fine hole, and a liquid guiding portion for supplying a liquid to the meniscus forming member, wherein the liquid supplied by the liquid guiding portion has the meniscus forming member An ink supply mechanism for adjusting a pressure in an ink chamber by a meniscus formed in a minute hole and elasticity of the film. 2. The ink supply unit, wherein the liquid guide portion contacts the surface of the meniscus forming member on the ink chamber side, extends into the ink, and supplies the ink in the ink chamber to the meniscus forming member. The ink supply mechanism according to claim 1, wherein the ink supply mechanism is configured.