JP2006142617A - Ink tank and recording head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ink tank which has high volume efficiency and can prevent an ink leakage from occurring through a simple manufacturing process or under a simple structure. <P>SOLUTION: A plug part 26 is of a cylindrical shape and measures somewhat larger than the measurement of a peripheral part which forms an opening 20 in the ink tank 11, so that the plug part 26 is fixed to the peripheral part by its elastic force. Thus the opening 20 can be closed and the interior of the ink tank 11 can be tightly closed to the outside. In addition, although the plug part 26 is connected with an annular elastic part 27 in the most part of the cylindrical shape, there is a part which is not connected with the annular elastic part 27 in some area other than the annular connection part. Consequently, when the ink tank 11 is fitted to a recording head, the plug part 26 is pressed by a joining aperture 39 of the recording head 30 as shown in Fig., and as a result, the part not connected with the annular elastic part 27 is significantly displaced, establishing communication between the interior of the joining aperture 39 and the interior of the ink tank 11. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an ink tank used in an ink jet printer or the like and a recording head that discharges ink supplied from the ink tank, and more specifically, from an ink tank to a recording head in a configuration in which the ink tank and the recording head are detachable from each other. The present invention relates to a configuration for supplying ink.

  The configuration for efficiently storing the ink in volume is to store the ink as it is (free state) without going through anything in a thin container such as an eye drop container. However, the conventional ink tank of this form has many disadvantages from the viewpoints of supplyability when ink is supplied from the ink tank to the recording head and prevention of ink leakage when the ink tank exists alone.

  For example, in general, the ink tank is often arranged above the recording head in order to maintain a good pressure relationship with the recording head when supplying ink, and is connected to the recording head below the ink tank. In addition, this configuration has an advantage that it is convenient when the user replaces the ink tank in the printer. However, in this configuration, a water head difference based on the height difference between the print head and the ink tank is added to the ink meniscus formed in the nozzle of the print head located at the lower portion. It is necessary to have a configuration for preventing leakage and favorably supplying ink accompanying ink ejection. A conventional ink tank that stores ink in a free state uses a relatively complicated configuration such as a valve to prevent ink leakage and maintain good ink supply.

  On the other hand, what was described in patent document 1 and patent document 2 is known as what prevents the ink leakage from a nozzle with a comparatively simple structure. In these, an ink absorber such as a sponge is arranged in an ink tank, and the ink is held by utilizing a capillary force acting between the ink impregnated in the ink tank. According to this configuration, for example, it is easy to store the ink tank alone by sealing the air communication hole and the opening, and it is possible to supply the ink to the recording head that has a stronger interface force while holding the ink. Thus, it is not necessary to provide a water head difference, and it is possible to provide an ink tank free from ink leakage. Further, the ink tank can be commercialized as a small and inexpensive ink tank as a whole.

  However, this configuration has a problem that only about 70% of the volume of the ink absorber can be filled with ink, and about 20% of the filled ink remains in the ink absorber and cannot be used. As an example of an ink tank that has solved this problem, one described in Patent Document 3 is known.

  FIG. 6 is a schematic cross-sectional view for explaining this improved type of ink tank. In the figure, 10 is an ink tank, 12 is an ink chamber, 13 is ink, 17 is a sealing member that closes the opening of the air communication hole 16 that is peeled off during use, and 18 is a press-fitting opening that injects ink during manufacturing. Indicates a stopcock that stops. Reference numeral 19 denotes a plug member of the ink supply port 20, which is removed when the ink tank 10 is attached to a recording head (not shown). A packing member 21 such as silicone rubber is disposed between the plug member 19 and the supply port 20 to seal the supply port 20. Reference numeral 22 denotes a transparent optical member for detecting the remaining amount of ink.

  This type of ink tank 10 is provided with an ink chamber 12 that holds ink 13 in a free state, and ink absorbers 15a, 15b, and 15c such as polyester felt, and a maze that communicates with the outside at the top. The ink absorber chamber 14 is provided with an air communication hole 16 in the form of a tube. By disposing an ink absorber in the ink absorber chamber 14, it is not necessary to provide a water head difference for ink supply, and it is possible to prevent ink leakage due to this, and an ink tank with improved volumetric efficiency. can do. That is, the ink absorber 15b functions as a back pressure generation unit, and the ink absorber 15c functions as a back pressure control unit when the surrounding environment changes. For example, when the air pressure decreases and the internal pressure of the ink tank relatively increases, the air in the upper layer portion of the ink chamber 12 expands. At this time, the ink absorber 15c absorbs the ink pushed out of the ink chamber 12 due to the expansion, whereby the change in the back pressure with respect to the recording head can be reduced and the back pressure within a certain range can be maintained. The ink absorber 15c has a density that is coarser than that of the ink absorber 15b, so that it is easy for air to pass through and it is difficult for ink to remain. On the other hand, the ink absorber 15a has a higher density than the ink absorber 15b, so that the capillary force is strong and the ink is easily collected.

JP-A 63-87242 JP 02-34349 A Japanese Patent No. 3278410

  As described above, since the ink tank of the type described in Patent Document 3 stores most of the ink in a free state, the volume efficiency is improved as compared with a type in which the ink tank is completely filled with an ink absorber. It has the advantages such as. However, the presence of the ink absorbers 15a and 15b in the ink circulation portion reaching the recording head and the resistance component of the ink circulation causes the following problems. Due to the presence of the resistance component, it takes time to inject ink in the ink tank manufacturing process. Alternatively, in order to increase the speed of the ink injection, for example, if a configuration is adopted in which suction is performed through the supply port 20 to increase the penetration of the ink into the ink absorber 15b, a suction process for ink injection or a configuration for the same Need extra.

  In addition, since this type of ink tank has functionally three openings or portions where the openings are blocked, the ink tank manufacturing process becomes much more complicated. In use, the user also needs to remove the sealing member 17 for the air communication port and the plug member 19 for the ink supply port. At this time, for example, the density of the ink absorber 15a is set to be high so that ink does not leak from the supply port 20 when the plug member 19 is removed. Then, as a countermeasure against the increase in resistance in ink supply, the supply port 20 is set to be larger. As a result, the ink tank becomes relatively large, which cannot contribute to downsizing of the apparatus, and is disadvantageous in terms of preventing ink leakage.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an ink tank having high volumetric efficiency and capable of preventing ink leakage with a simple manufacturing process or structure, and its An object of the present invention is to provide a recording head that is used with an ink tank.

  Therefore, in the present invention, an ink tank for storing ink, which is in contact with one opening that communicates the inside of the ink tank for storing ink with the outside of the ink tank, and a member that forms the opening. And an elastic plug portion that is connected to the annular elastic portion and engages with the opening to close the opening, and a portion of the elastic plug portion is located inside the ink tank. And an elastic plug portion capable of communicating between the inside of the ink tank and the hole at the center of the annular elastic portion.

  Also, an ink tank for storing ink, wherein one opening that communicates the inside of the ink tank that stores ink with the outside of the ink tank, and an annular elastic portion disposed in contact with a member that forms the opening And an elastic plug portion that is connected to the annular elastic portion and engages with the opening to close the opening, and a part of the elastic plug portion is displaced toward the inside of the ink tank, And an elastic plug portion capable of communicating between the center of the annular elastic portion and a recording head that discharges ink supplied from the ink tank. When joining with ink, a joint opening is provided in the center of the annular elastic section so as to push the annular elastic section away from the annular elastic section and displace the elastic plug section in the ink tank. Ink And yield, characterized in that comprises a.

  According to the above configuration, when the ink tank is attached to the recording head, when the insertion port of the recording head is engaged with the annular elastic portion and inserted so as to be pushed away against the elastic force, the tip of the bonding port is The elastic stopper part that blocks the opening of the ink tank hits the elastic stopper part, and the elastic stopper part that is partially weakly integrated with the annular elastic part is pushed into the ink tank. The ink corresponding to the volume of the pushed-in elastic plug portion is pushed out to the recording head side through the opening, and there is a space substantially sealed by the joint port and the annular elastic portion. On the other hand, since the ink absorber on the recording head side occupies most of the inside of the joint, the pushed ink is sucked by the capillary force while being pushed into the ink absorber. Ink is supplied from the ink tank to the recording head by configuring the recording head to exchange gas and liquid via the ink absorber.

  As described above, a thin-walled integrally sealed ink tank by blow molding that can store ink at a 100% volume ratio in a free state without using an absorber in the ink tank and can consume 100% of the ink. In addition, the ink tank may be provided at a single opening so that, for example, an air intake step during liquid injection is not required, and the plugging step after liquid injection is performed together with the O-ring attachment. The process can be shortened. Further, even if the ink container is pressed, it is possible to make it difficult to remove the tank by the elastic protrusion. Furthermore, even if the ink tank is separated with ink remaining in the tank, the elastic stopper portion is restored to the state in which the tank opening is closed, so that ink leakage can be minimized.

  FIG. 1 is a cross-sectional view schematically showing an ink tank 11 and a recording head 30 equipped with the ink tank 11 according to an embodiment of the present invention. FIG. 2 is a schematic cross-sectional view of the ink tank 11 alone not attached to the recording head as viewed from the side in the posture shown in FIG.

  In FIG. 1, a recording nozzle portion 31 is disposed at the lowermost portion of a recording head 30 mounted on a carriage (not shown) that can scan the recording medium. The recording nozzle unit 31 includes 256 nozzles arranged at a density of 300 dpi, each ejecting ink, and a nozzle ink chamber 32 that communicates with these nozzles in common and supplies ink according to the ink ejection from each nozzle. Is provided. Ink is supplied to the nozzle ink chamber 32 through a filter 34 and an ink passage 33 from a sub tank 35 that temporarily stores ink. Each nozzle of the recording nozzle unit 31 is provided with a heating element (not shown) for generating bubbles by energization in order to eject ink droplets. Further, the recording head 30 includes a cylindrical joint port 39 at the upper part thereof. A rectangular columnar ink absorber 40 is disposed inside the joint port 39, and this absorber extends downward so as to fill a part of the sub tank 35. Although not shown in the drawing, the recording head unit 30 is also provided with a printed wiring board for supplying a recording signal to the heating element.

  As shown in FIG. 2, when the ink tank 11 exists alone, the elastic plug member 25 closes the opening of the ink tank 11 serving as a supply port to seal the inside of the ink tank from the outside. Specifically, the elastic plug member 25 includes a plug portion 26 and an annular (donut-like) elastic portion 27. Among them, the plug portion 26 has a cylindrical shape, and the size thereof is determined to be larger than the size of the peripheral portion forming the opening 20 in the ink tank 11, so that the plug portion 26 is fixed to the peripheral portion by its elastic force. Thereby, the opening 20 of the ink tank can be closed and the inside of the ink tank can be sealed from the outside. The plug portion 26 is connected to the annular elastic portion 27 in most of the cylindrical shape, but is not connected to the annular elastic portion 27 at a part other than the annular connecting portion (shown in FIG. 4). There is a break 29). When the ink tank 11 is attached to the recording head, as shown in FIG. 1, the plug portion 26 is pressed by the joint port 39 of the recording head 30, thereby causing the elastic plug member 26 to be greatly displaced into the ink tank. The inside of the joint 39 communicates with the inside of the ink tank 11.

  Referring again to FIG. 1, when the ink tank 11 is mounted while being positioned according to a guide (not shown) formed in the housing of the recording head unit 30, the joint 39 of the recording head is connected to the annular elastic portion 27 of the ink tank 11. The annular elastic portion 27 around the center hole portion is pushed into the center hole portion so as to enter. Then, as described above, the distal end portion of the joint port 39 pushes away the plug portion 26 that closes the opening 20 and reaches the ink chamber.

  At this time, the ink that has been pushed into the ink chamber 12 of the ink tank is pushed out of the ink tank through the opening 20. At this time, the tank-side opening 20 portion has a sealed space formed by the head-side joint 39 and the ink absorber 40 and the annular elastic body 27 in the inside, so that the extruded ink is further outside. In addition, since the most part of the sealed space is occupied by the absorber 40 of the cylindrical joint 39 of the head, the ink pushed out from the tank is the tip of the ink absorber 40 of the head. The filter part 42 is touched, and while being absorbed, the air component contained in the ink absorber 40 of the head is exchanged and falls to reach the sub tank 35. The air in the sub tank 35 enters the ink tank 11 through the sealed space adjacent to the opening 20 and the opening 20, and when the sub tank 35 is filled with ink and the air disappears, the ink dropping also stops.

As described above, the ink tank 11 and the sub tank 35 of the recording head 30 form a sealed space that is shielded from the outside air by the annular elastic portion 27 in a joined state, and the air in the sub tank 35 is formed in the upper layer portion of the ink tank 11. In the state where the ink has moved and instead moved to the sub tank 35 side, the inside of the ink tank 11 and the inside of the sub tank 35 are the same as the atmospheric pressure, so that the ink filling the orifice of the recording nozzle portion 31 and the ink absorber 40 can be obtained. The surface tension prevents leakage of ink from the two openings. When the ink tank 11 is attached or detached, the recording nozzle portion 31 is in a capping state (not shown), and there is no problem even if a small amount of ink leaks due to the pressing pressure. In this state, a small amount of ink is sucked from the recording nozzle unit 31 by a suction pump (not shown) connected to the cap, so that new ink is guided to each orifice unit, and the ink chambers of the sub tank 35 and the ink tank 11 are light. Negative pressure is reached. The sub tank 35 is opened to the outside air through an air communication path 36 including an ink absorber 40 and an overflow ink storage part 37. The ink absorber 40 impregnated with ink maintains a certain pressure difference between the outside air and the inside air of the sub tank 35. The pressure difference is determined by the capillary force acting between the ink absorber 40 and the impregnated ink. The bore size of the ink absorber 40 is selected so that the ink does not leak from the orifice and can be ejected, for example, about ± 30 mmH ₂ O.

  When ink is consumed by ink ejection during the recording operation, the ink is supplied from the ink passage 33 to the recording nozzle unit 31 via the filter 34, and the pressure inside the sub tank 35 and the ink tank 11 decreases. Further, when the discharge is continued and the internal pressure of the sub tank 35 drops more than a certain level, and the pressure difference between the inside and outside exceeds a certain interfacial force acting between the ink absorber 40 and the impregnated ink, the outside air is little by little. It penetrates in the form of bubbles and relieves pressure drop. The outside air that has entered the sub tank 35 enters the ink tank 11 through the sealed space of the joint portion 39, and the corresponding amount of ink is supplied to the sub tank 35. While there is ink in the ink tank 11, the gas-liquid exchange is repeated for the amount of ink consumed, and the sub-tank 35 is kept filled with ink. When all the ink in the ink tank 11 is consumed, the ink level in the sub tank 35 starts to drop. An ink remaining amount detecting member 22 is disposed in the sub tank 35, and an alarm is generated when the ink level is lowered and the ink remaining amount detecting member 22 is exposed to the air. The alarm is issued when ink remains in the lower part of the sub tank 35, and the portion where the ink absorber 40 blocks the atmospheric communication path 36 and the filter 34 are not exposed to the air. Although the internal pressure decreases with ink consumption, the internal pressure increases conversely when the atmospheric pressure drops or the ambient temperature drops. At this time, the expanded air in the upper part of the ink tank 11 pressurizes the ink in the sub-tank 35 that communicates with the outside air in a sealed state, and when the interfacial force acting on the ink absorber 40 impregnated with ink exceeds the ink, Extruded. Since the interfacial force acting on the nozzle orifice is sufficiently stronger than the interfacial force acting on the ink absorber 40, ink is not pushed out from the nozzle. When ink consumption progresses and the ratio of air in the ink tank 11 increases, the volume that expands increases and the amount of ink that is pushed out increases. When a large amount of ink is pushed out, the ink reaches the overflow ink storage portion 37. By securing a space corresponding to the maximum amount of ink to be pushed out as the ink storage portion 37, expansion of the inside air due to environmental changes is absorbed without causing ink to leak outside. When the ink that has accumulated in the overflowing ink containing portion 37 begins to be consumed or the internal pressure that has risen begins to return to its original state, the ink returns to the ink containing portion 37 from the atmosphere communication path 36 close to the opening 38 and ink absorption. Return to the ink tank 11 via the body 40. The ink absorber 40 is preferably a capillary structure in which a large number of hydrophilic SUS (stainless) thin plates of about 0.1 mm are stacked.

  In the ink tank 11 described above, even if the recording head 30 is removed with a sufficient amount of ink remaining, the annular elastic member 27 is adjacent to the opening 20 of the ink tank, and its inner diameter is as thin as several millimeters in the open state. Is difficult to leak due to surface tension, but is vulnerable to vibration and pressure. For this reason, in the present embodiment, as described above, the plug portion 26 is connected to the annular elastic portion 27 for the most part and partially disconnected, so that when the recording head 30 is separated, the non-connected portion is deformed. The opening thus made returns to its original shape and closes the opening 20 by the restoring force of the elastic portion. Thereby, even if ink leakage should occur, a small amount is sufficient. Further, in the stopper portion 26, the entire circumferential top is formed into the shape of a small protruding portion 28, and the edge of the opening portion 20 is sandwiched in a state where the plug portion 26 is pressed and sealed as shown in FIG. Even if the container is pressed, the elastic protrusion can prevent the tank from coming out.

  In addition, this projection part has the same effect even if it exists in part rather than circumferential shape as shown in FIG. Moreover, the connection part of the plug part 26 and the donut-shaped elastic part 27 may make the cut | interruption part 29 the partial fine detail. Further, in FIGS. 1 and 2, since the receiving portion of the annular elastic portion 27 is in the portion of the opening 20, it must be made a separate part together with the opening side wall portion 41 for molding. FIG. 5 shows an elastic plug member 25 for the opening 20 of the ink tank 11 that can be molded as a single component. A thin annular elastic portion 44 that wraps the opening side wall portion 41 outside the annular elastic portion 27 is disposed, and is fitted into a recess disposed outside the opening side wall portion 41 so as to sandwich the side wall. The elastic plug member 25 having such a configuration can be assembled in one step, and does not come off even if the outer wall of the ink tank 11 is pressed with some force.

FIG. 2 is a schematic cross-sectional view illustrating a state where an ink tank and a recording head according to an embodiment of the present invention are joined. FIG. 2 is a schematic cross-sectional view showing a single ink tank shown in FIG. 1. It is a typical sectional view showing other embodiments of an elastic stopper part attached to an ink tank concerning an embodiment of the present invention. It is typical sectional drawing which shows other embodiment of the said elastic stopper part. It is a typical sectional view showing an ink tank simple substance concerning other embodiments of the present invention. FIG. 10 is a schematic cross-sectional view illustrating a conventional ink tank.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Ink tank 12 Ink chamber 13 Ink 20 Ink tank opening 22 Ink remaining amount detection member 25 Elastic plug member 26 Plug portion 27 Annular elastic portion 28 Projection portion 29 Cut 30 Recording head 31 Recording nozzle portion 32 Nozzle ink chamber 33 Ink passage 34 Filter 35 Subtank 36 Atmospheric communication path 37 Overflow ink storage part 38 Opening port of atmospheric communication path 39 Joint port 40 Ink absorber 41 Outer wall of ink supply port 42 Filter 43 Concave part of opening side wall 44 Second annular elastic part

Claims (6)

An ink tank for storing ink,
One opening for communicating the inside of the ink tank for storing ink with the outside of the ink tank;
An annular elastic portion disposed in contact with a member forming the opening;
An elastic plug portion that is connected to the annular elastic portion and engages with the opening to close the opening, and a part of the elastic plug portion is displaced toward the inside of the ink tank, and the inside of the ink tank and the An elastic plug portion capable of communicating with the hole in the center of the annular elastic portion;
An ink tank characterized by comprising   The elastic plug portion has a cylindrical shape, and a protrusion is provided at a circumferential top portion on the ink tank side in the cylindrical shape, and when engaging with the opening, the top portion and a part of a member forming the opening, The ink tank according to claim 1, wherein the ink tank is engaged.   The ink tank according to claim 2, wherein the protrusion is partially provided at the circumferential top.   The annular elastic portion is provided with a narrower second annular elastic portion on the outer side thereof, and the second annular elastic portion is engaged with a side wall arranged outside the opening so as to sandwich the side wall. The ink tank according to any one of claims 1 to 3, wherein:   The ink tank according to claim 1, wherein the ink tank stores ink. An ink tank for storing ink, wherein one opening for communicating the inside of the ink tank for storing ink with the outside of the ink tank; and an annular elastic portion disposed in contact with a member forming the opening; An elastic plug portion that is connected to the annular elastic portion and engages with the opening to close the opening, and a part of the elastic plug portion is displaced toward the inside of the ink tank, and the inside of the ink tank and the An ink tank provided with an elastic plug portion capable of communicating with a hole in the center of the annular elastic portion, and a recording head that discharges ink supplied from the ink tank,
When joining with the ink, a joint port that enters the hole in the center of the annular elastic portion so as to push the annular elastic portion away and displaces the elastic plug portion inward of the ink tank;
An ink absorber disposed inside the joint,
A recording head characterized by comprising:

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