HK1110276A - An ink tank cartridge for an ink-jet type recording apparatus - Google Patents

Description

Ink box for ink-jet recording equipment

Technical Field

The present invention relates generally to an ink supply printer that supplies ink from an ink supply tank, and more particularly, to an ink supply tank that can continuously supply ink to a print head while avoiding adverse effects due to temperature, air pressure variations, or fluctuations. The ink supply channel of the present invention can hold a relatively large amount of ink, with a relatively large percentage of the ink in the channel being delivered to the printhead. The present invention also includes an ink tank having transparent sidewalls so that a user can easily determine the amount of ink remaining in the tank; the invention also includes a damping device that is not intended to move ink in the ink feed slot.

The present invention also relates to an ink cartridge for an ink jet printer in which an ink jet recording head and an ink cartridge are mounted on a movable carriage, and in particular, when the ink in the old ink cartridge is used up, the ink cartridge is replaced with a new one.

A prior art ink jet printer in which an ink containing device and an ink jet recording head are mounted on a carriage is disclosed in european patent No 581,531. In the disclosed printer, in order to prevent a printing defect caused by the movement of the ink cartridge due to the movement of the carriage, the fluctuation of the ink level or the air bubbles generated therewith, the ink cartridge is partitioned into two areas of ink. A first region of the cartridge is adjacent to the recording head and contains ink infiltrated into a porous member, and a second region contains liquid ink without the porous member. This structure allows the ink to be transported to the recording head through the porous member, and therefore, problems caused by the movement of the ink in the ink cartridge can be avoided to some extent.

The porous member is held in fluid communication with the recording head by a projection member inserted into a hole formed in a side wall of the ink cartridge. However, such a structure cannot be applied to the case of a recording head in which it is necessary to stop bubbles from entering the pressure chamber, for example, an ink jet printer using a piezoelectric vibrator as an ink jet actuator.

Thus, an ink jet printer that solves the above problems has been produced.

Generally speaking, in accordance with the invention, an ink-fed printer is provided. Ink is supplied to the printhead by an ink supply system including an ink tank having an ink supply and a pair of side walls. An ink absorbing member is provided in the ink tank in the vicinity of the ink supply port, and occupies a space smaller than the total volume of the ink tank. The walls of the ink supply channel are transparent so that a user can more easily determine the amount of ink remaining in the ink supply channel.

An ink receiving and transporting member, one end of which is located in the ink supply port, projects into the ink supply channel, in which case the ink absorbing member rests on the ink receiving and transporting member and is locally compressed. The ink receiving and transporting member has an elongated ink passage in fluid communication with the print head, and ink is supplied from the ink absorbing member to the print head.

Specifically, the ink supply cartridge has an ink chamber that stores ink and a foam chamber that receives a porous member that absorbs ink. A partition wall separates the ink chamber from the foam chamber, and the partition wall has an opening to place the ink chamber in fluid communication with the foam chamber. The ink cartridge also has an ink supply port. A funnel-shaped seal member is installed in the ink supply port and supplies ink to a recording head by a pressure difference generated through the porous member. The sealing member is upwardly facing in the ink supply port, and is elastic.

When an ink supply needle of a recording head is inserted into an ink supply port, the tip of the needle elastically contacts a seal. Since the seal is funnel-shaped with the opening facing upward, it is easily deformed to abut against the ink supply needle. Moreover, because of its elasticity, it is more tightly attached to the needle. In this way, the relative mounting error between the ink supply needle and the ink supply port can be accommodated. So that the ink supply port can be reliably sealed.

Disclosure of Invention

It is therefore an object of the present invention to provide an improved ink cartridge for an ink jet printer.

An object of the present invention is to provide a high-quality and high-reliability ink-supply printer of a simple structure, which can supply a stable and appropriate amount of ink from an ink supply tank to a print head with less influence caused by environmental changes such as temperature and pressure fluctuation.

Another object of the present invention is to provide an ink cartridge for an ink jet printer, which requires a minimum force for mounting the ink cartridge, has a large difference in mounting error of an ink supply needle, can achieve complete sealing in cooperation with a recording head, and forms a dead space as small as possible.

It is still another object of the present invention to prevent air bubbles from entering the recording head while maintaining a negative pressure in the chamber in which the porous member is installed.

According to the present invention, there is provided an ink cartridge for an ink jet recording apparatus, comprising a gas release port on a surface of the ink cartridge, the gas release port being sealed by a gas-impermeable seal member so as to selectively seal the gas release port when the ink cartridge is not in use and not to seal the gas release port when the ink cartridge is put into use; characterized in that a plurality of air release holes sealed by the sealing member are provided, each air release hole communicating with a groove formed on a surface of the ink cartridge; the seal includes a main portion permanently sealing the groove and a tongue removably connected to the main portion by a neck.

In the above ink cartridge for an ink jet recording apparatus, different patterns and colors may be printed on the sealing member and the tongue piece, respectively, and the drama part serves as an interface between the tongue piece and the main part.

In the above ink cartridge for an ink jet recording apparatus, the air release opening is formed at least partially as a curved groove on the surface of the ink cartridge to prevent evaporation of the ink.

Other objects, features and advantages of the present invention will become more apparent in the light of the following description, with reference to the accompanying drawings, in which the illustrated examples represent preferred embodiments of the invention, but are not to be construed as limiting the invention.

Accordingly, the invention includes several steps and the relation of one or more of such steps to each of the others; also included are devices embodying the technical features of construction, combination of parts and assembly of parts with which those steps are carried out; but also what is exemplified in the following detailed disclosure, and the scope of the invention will be indicated in the claims.

Drawings

For a fuller understanding of the present invention, reference is made to the following description taken in conjunction with the accompanying drawings, in which:

fig. 1 is a schematic view showing an ink supply system of an ink jet type recording apparatus of an embodiment of the present invention;

FIG. 2 is a cross-sectional view of a multi-color ink jet printer cartridge constructed in accordance with a first embodiment of the invention;

FIG. 3 is a cross-sectional view of the first embodiment rotated 90 from the orientation of FIG. 2;

FIG. 4 is a perspective view showing the ink cartridge of FIGS. 2 and 3 with the cover removed;

FIG. 5 is a perspective view showing a monochrome ink cartridge constructed according to a second embodiment of the present invention;

FIG. 6(a) is a top view of a cover of the multicolor ink cartridge of FIG. 2;

FIG. 6(b) is a top view showing the lid with an additional seal thereon;

FIG. 7(a) is a sectional view showing a seal member of the present invention with an ink supply needle inserted therein;

FIG. 7(b) is a cross-sectional view of the seal before insertion of the ink supply needle;

FIG. 8 is a graph showing the relationship between ink consumption, pressure value and amount of ink remaining in an ink chamber;

FIG. 9 is a partial cross-sectional view of an ink cartridge showing an interface between an ink chamber and a foam chamber according to a third embodiment of the present invention;

FIG. 10 is a partial cross-sectional view of an ink cartridge of a fourth embodiment of the present invention, showing the interface between the ink chamber and the foam chamber;

FIG. 11 is a partial cross-sectional view of the interface between the ink chamber and the foam chamber of an ink cartridge constructed in accordance with a fifth embodiment of the invention;

FIG. 12 is a cross-sectional view taken along line 33-33 of FIG. 11;

FIG. 13 is a partial cross-sectional view showing the interface between an ink chamber and a foam chamber of an ink cartridge constructed in accordance with a sixth embodiment of the invention;

FIG. 14 is a cross-sectional view taken along line 35-35 of FIG. 13;

FIG. 15 is a sectional view showing an ink cartridge constructed according to a seventh embodiment of the present invention;

FIG. 16 is a sectional view showing an ink cartridge constructed according to an eighth embodiment of the present invention;

FIG. 17 is a cross-sectional view of an ink cartridge for an ink jet printer constructed in accordance with a ninth embodiment of the invention;

FIG. 18 is a cross-sectional view of an ink cartridge of a ninth embodiment of the present invention rotated 90 from the orientation of FIG. 17;

Detailed Description

The printer head of the present invention can be used in a four-color printer plotter or a color image printer having a four-color ink system and ink nozzles corresponding to the four ink colors. A four-color plotter uses ink, red, green and blue inks to move either the print head or the print sheet, or both, while ejecting the inks, corresponding to a desired color, against the sheet at a specified location, as in a conventional ink jet print head, to form dots. By repeating the above-described cycle, desired characters and images can be recorded. The present invention is applicable to various ink jet printers including a print head that ejects ink in an ink chamber as ink droplets in accordance with an input print signal using a thermal or piezoelectric displacement or transducer generated by a heating resistor or the like. The ink supply channel of the present invention enables ink to be continuously supplied to the ink chamber through the elongated passage.

In a color image printer using inks of four colors, i.e., ink color, red, green, and blue, a print head scans a print sheet in a direction perpendicular to a feeding direction of the print sheet, forms a row of dots in one scanning stroke, and the print sheet is fed forward by a pitch of the row of dots to record an image. In a seven-color printer, four-color inks, i.e., black, yellow, magenta, and cyan, are used to form red, green, and blue colors on a printing sheet by overprinting two colors of three desired colors other than the ink colors, so that a color image of seven colors can be recorded.

The present invention relates generally to printer heads and more particularly to ink feed channels, and a detailed description of the overall printer structure will be given by way of example only.

Fig. 1 is a schematic diagram showing an ink supply system of an ink jet recording apparatus of an embodiment of the present invention.

The printhead assembly 1 of an ink jet printer is connected to an ink tank 3 by a connector 2. Ink is supplied from the ink tank 3 to the printhead assembly 1 through the hollow needle and the ink supply passage 2b of the connector 2, and therefore the printhead assembly 1 ejects ink droplets in accordance with a print signal.

The apparatus shown in figure 1 also comprises a cap 4 mounted in the non-printing region and a drive mechanism (not shown) presses the cap 4 against the nozzle plate of the printhead assembly 1 to prevent nozzle orifice dry operation. The cap 4 communicates with a vacuum pump 5 via a tube 8, and the control means 6 operates the vacuum pump 5 to draw ink from the printhead assembly 1 through the cap 4. The apparatus shown in fig. 1 also comprises a waste ink tank 7 connected to the outlet of the vacuum pump 5 via a pipe 9.

The recording head may be of any one of the structures described in, for example, european patent publications nos. 581,531, 609,863, 584,823 and the like.

The shape of the ink cartridge is such that it can be installed with a small amount of force and can accommodate a certain degree of installation error. Referring first to fig. 2 and 3, an ink cartridge constructed in accordance with a first embodiment of the present invention is shown. The partitions 502 and 503 shown in fig. 3 partition the cartridge 501 into three chambers 504, 505, and 506. The middle partition wall 510 partitions each of the three chambers 504, 505, 506 into a foam chamber 511, 511 ' or 511 "for containing the corresponding porous member 520, 520 ' or 520" and an ink chamber 512, 512 ' or 512 "for containing liquid ink. The foam compartment 511, 511 'or 511 "is sized to receive a corresponding porous material 520, 520' or 520".

The volume of each porous member 520, 520 'and 520 "is determined to be greater than the volume of each foam cell 511, 511' or 511" so that the porous member held within the respective foam cell will be compressed in a preferred embodiment. The ratio of the volume of each foam chamber 511, 511 'or 511 "to each ink chamber 512, 512' or 512" is determined so that each foam chamber 511, 511 'or 511 "is sized to hold 20% to 30% more ink than the corresponding ink chamber 512, 512' or 512".

When three colors of inks are contained in one ink cartridge shown in fig. 2 to 4, it is difficult to see the difference in the amount of ink left in the chamber caused by uneven consumption of the inks of different colors. When one color of ink is used up, the user wants to dispose of the ink cartridge without unnecessarily worrying about leakage of the other colors of ink left in the ink cartridge. When the ink cartridge of the present invention is handled, the ink can be prevented from flowing out of the ink cartridge because the ink of each color is absorbed by each corresponding porous member, thereby protecting the surroundings from leaking the ink.

Ink supply ports 513, 513 'and 513 "(not shown) are formed in the respective foam chambers 511, 511' and 511" of the ink cartridges 501. Chamber 511 is one example of each of chambers 511, 511', and 511 ". Each of the ink supply ports 513, 513 'and 513 "is adapted to cooperate with a corresponding ink supply needle of the recording head, which is inserted at the lower end of each of the foam chambers 511, 511' and 511".

Referring now to fig. 2 and 3, a lid 516 seals the upper end of the cartridge 501. Two ink charging ports 514, 515 are formed in the cover 516 at positions corresponding to the foam chambers 511. Similarly, in FIG. 6(a), each chamber 511, 511 'and 511' includes a respective ink loading port 514 and 515, 514 'and 515', and 514 'and 515'. The projections 516a and 516b shown in fig. 2 are formed integrally with the inner surface of the cover 516 and are located in the foam chamber 511 so as to surround the ink charging ports 515 and 514, respectively. The projections 516a and 516b compress the porous member 520 toward the bottom wall of the foam chamber 511, and the ink supply port 513 is formed on the bottom wall. Protrusions 516a 'and 516 b' and 516a "and 516 b" are similarly formed on the inner wall of the cover 516, within the foam chambers 511 'and 511 ", as shown in fig. 3, having ink supply ports 513' and 513", respectively.

The lower tip of the projection 516a opposite to the ink supply port 513 is located lower than the lower tip of the projection 516b, so that the portion of the porous member in the vicinity of the ink supply port 513 is compressed most.

Ridges 522, 522 ' and 522 "(collectively 522) are formed on the bottom of each foam compartment 511, 511 ' and 511", respectively, that together with the lid 516 compress the porous members 520, 520 ' and 520 ". Notches 523, 523' and 523 "(collectively 523) are formed at the upper ends of the respective protuberances 522 to define a space having a fixed open area. Through-holes 524, 524', and 524 "(collectively 524) are formed in the respective bumps 522. One end of each through-hole 524 is in fluid communication with the space defined by the recess 523, and the other end is in communication with a corresponding seal (collectively 530) to be described below. Filters 525, 525' and 525 "(not shown) (collectively 525) are secured to the upper ends of the recesses 523, respectively.

Seals 530, only one of which is shown, are respectively provided at lower ends of the ink supply ports 513, 513', and 513 ″, which are made of an elastic material such as rubber, and are shaped like a funnel with an opening upward. The lower end of the tubular portion 531 is thicker than the other portions. The respective upper circular edges 533 of the conical portions 532 of the respective seals 530 are in contact with the stepped portions 513a of the respective ink supply ports 513, 513', and 513 ″. Each seal 530 has a flange 535 that sits in a groove 527 in the inner wall of the ink supply port 513. The interface between the circular tubular portion 531 and the conical portion 532 is a thin connecting portion 534.

With this structure, the sealing members 530 can be fixedly installed in the respective ink supply ports 513 by the circular tube portions 531. In addition, the respective upper step portions 513a may prevent the upper rounded edge 533 from moving upward. Therefore, even when the corresponding ink supply needle is inserted or withdrawn, the seal is sufficiently fixed in the ink supply port 513. Since the conical portion 532 can be used to seal between the seal of the corresponding ink supply port 513 and the ink supply needle by the thin connecting portion 534, the conical portion can be slightly moved without deformation. Therefore, the gas seal can be maintained between the respective seal member and the supply needle while accommodating relative mounting error between the respective supply needle and the supply port.

The intermediate partition wall 510 partitions the foam chambers 511, 511 ' and 511 "and the ink chambers 512, 512 ' and 512", respectively, and has communication holes 519, 519 ' and 519 ". The slots 519a, 519a 'and 519a ″ extending to a predetermined height communicate with the through holes 519, 519' and 519 ″ respectively for gas-liquid exchange. Porous members 520, 520 'and 520 "are respectively provided in the foam chambers 511, 511' and 511 'of each corresponding pair of the foam and ink chambers 511 and 512, 511' and 512 'and 511" and 512 "in such a manner as to press the porous members toward the corresponding communication holes 519, 519' or 519". Ribs 518, 518' and 518 ″ are formed in the respective ink chambers on the rear wall 501a of the cartridge 501. Between each corresponding pair of cells 511, 512, a separate communication hole is formed, which is formed on the partition wall 510 and extends only a length thereof.

In a second embodiment of the present invention, one ink cartridge is used for single color ink. The size of the ink cartridge 5100 for the monochromatic or black ink may be smaller than that for the color ink, but the volume of the ink chamber 5112 of the black ink cartridge is larger than that of the corresponding ink chamber for each color. According to the second embodiment of the present invention, a partition 5117 is formed in the ink cartridge 5100 for black ink shown in fig. 5, and the partition 5117 extends between a middle partition 5110 partitioning a foam chamber 5111 and an ink chamber 5112 and a side wall 5100a of the cartridge 5100, thereby partitioning the ink chamber into two small chambers 5112a and 5112 b. This structure can prevent the deformation of the ink container 5100 caused by negative pressure generated during an ink charging operation and deformation caused by external pressure during use, which will be described later, thereby preventing ink leakage. The small cells 5112a and 5112b are in fluid communication with the foam chamber via communication holes 5119 in the middle partition 5110, the communication holes 5119 extending only a length above the middle partition 5110. In addition, a communication hole is formed at the bottom of the partition 5117.

On the inside surface of the wall 5100a, which is easily visible when the cartridge is mounted to the carriage, there are a number of ribs 5118 extending along the inside surface. These ribs can facilitate ink flow down the wall 5100a, and by looking at the liquid level, a user can easily determine the amount of ink remaining in the cartridge.

Reference is now made to fig. 6(a) and 6(b), which illustrate a cap 516 constructed in accordance with a first additional embodiment of the present invention. Ink-containing holes 514, 514 'and 514' and 515, 515 'and 515' are formed in the cover 516 at positions corresponding to the porous members 520, 520 'and 520' in the cartridge 501. The through-holes 541, 541 ' and 541 "communicate with the ink-holding holes 514, 514 ' and 514" via the grooves 540, 540 ' and 540 ", respectively.

When a closing plate 542 for covering the ink containing holes 514, 514 'and 514' and 515, 515 'and 515' and the air release ports 541, 541 'and 541' is fixedly attached to the upper side of the cover 516 shown in fig. 6, the grooves 540, 540 'and 540' form an elongated tube together with the closing plate 542 after the foam chambers 511, 511 'and 511' are filled. The tongue 545 of the closure plate 542 extends from the lid 516 and the tongue 545 has a pre-portion 543 which is located at the midpoint of the path of the vents 541, 541' and 541 ". When the tongue-shaped piece 545 is released from the cover 516, the tongue-shaped piece 545 is easily separated from the closed pole 542. This may in turn expose the bleed opening 541, but not the other portion of the lower side edge of the closure plate 542.

In a preferred embodiment, a pattern, for example, composed of letters and graphics, is printed on the main portion 544 of the permanent closure grooves 540, 540' and 540 "of the closure 542. The design, color or other printing on the tongue 545 is different than that printed on the main portion 544 of the closure panel 542, and the tongue 545 is connected to the main portion 544 by a neck 543.

For example, in yet another embodiment, the base color of the main portion 544 of the closure panel 542 is blue, with black letters and other graphics printed thereon. The base color of the tongue 545 is, for example, yellow or red, as opposed to the base color of the main portion 544. The color of letters and figures printed on the substrate is mainly black or blue. Thus, since the main portion 544 and the tongue-shaped piece 545 are different in color and pattern from each other, they can be distinguished. Therefore, when the tongue-shaped piece 545 needs to be removed, the user's attention can be attracted.

Each of the ink supply ports 513, and 513 "is sealed by a film 546 shown in fig. 2, and the ink supply needles are hermetically inserted into the ink supply holes 514, 514 'and 514" and 515, 515' and 515 ", respectively. The first assembly ink holes 514, 514 'and 514 "are put in communication with a vacuum device, while the second assembly ink holes 515, 515' and 515" are closed.

The vacuum device reduces the pressure within each foam chamber 511, 511 'and 511 "and each ink chamber 512, 512' and 512". When the pressure is reduced to a predetermined value, the vacuum operation is stopped and the first assembly ink hole is closed. Thereafter, the second ink-containing hole is made to communicate with the measuring tube containing ink. The ink contained in the measurement pipe is sucked into the ink cartridge in a vacuum state, and then is absorbed by the corresponding porous members 520, 520 ', and 520 ", and thereafter flows into the ink chambers 512, 512 ', and 512" through the communication holes 519, 519 ', and 519 ", respectively.

After a prescribed amount of ink flows into the corresponding ink chambers, a closing plate 542 is fixedly attached to the surface of the cover 516 so as to seal the device holes 514, 514 'and 515, 515' and 515 ", the grooves 540, 540 'and 540", and the communication holes 541, 541' and 541 "in a depressurized state. Thereafter, the closing plate 542 maintains the foam chambers 511, 511 ', and 511 ' and the ink chambers 512, 512 ', and 512 ″ in a reduced pressure state.

Before using the ink cartridge, the tongue 545 of the closure plate 542 is removed to break the neck 543 of the tongue 545 away from the main portion 544. Thus, ink feed holes 514, 514 ' and 514 "are in fluid communication with vent ports 541, 541 ' and 541" via grooves 540, 540 ' and 540 ". Similarly, the foam chamber is in fluid communication with the atmosphere via slots 540, 540 'and 540 "and vents 541, 541' and 541". Thus, the ink cartridge is vented while preventing evaporation of the ink.

Referring now to fig. 7(a) and 7(b), the ink supply port 513 of the ink cartridge is positioned to be aligned with the head ink supply needle 550. Thereafter, the ink cartridge is pushed toward the recording head when it is inserted. The conical portion 551 of the ink supply needle 550 penetrates the membrane seal 546 to mate with the bore of the seal 530 shown in fig. 7 (a). Since the opening of the sealing member 530 is upward, the supply needle 550 passes through the sealing member 530 when the conical portion 551 of the supply needle 550 elastically deforms the sealing member 530.

When the ink cartridge is used, the ink supply needle 550 passes through the sealing member 530. The resiliency of the connecting portion 534 of the seal 530 urges the conical portion 532 into engagement with the supply needle 550. The ink supply port 513 of the ink supply needle 550 can achieve gas sealing even if the ink supply needle 550 of the recording head is slightly misaligned from the center of the seal 530.

After the ink cartridge is mounted, in order to introduce ink into the recording head or to utilize the ejection performance of the ink, a negative pressure is applied to the recording head and the penetrating supply needle 550 to cause the ink in the cartridge to flow into the recording head through the supply needle 550. This high negative pressure applied to the cartridge, due to the pressure differential, causes the conical portion 532 of the seal 530, which hermetically seals and isolates the cartridge from the atmosphere, to rise toward the interior of the cartridge as shown in fig. 7 (a). Accordingly, this pressure differential helps to resiliently press the conical portion 532 of the seal 530 against the ink supply needle 550, thereby helping to hermetically seal the ink cartridge.

Even if the ink supply needle 550 is not completely inserted into the seal 530, as long as the conical portion 551 of the ink supply needle 550 keeps in contact with the conical portion 532 shown in fig. 7(b), the elastic force in the conical portion 532 of the seal 530 keeps the conical portion 532 in contact with the ink supply needle 550.

Therefore, even if the needle is not completely inserted, airtightness of the seal 530 and the supply needle 550 can be ensured.

Since the top of the supply needle 550 is sealed when in contact with the seal 530, the dead space inside the ink cartridge can be made small as shown, and air bubbles generated by the piston effect when inserting the ink cartridge into the recording head can be prevented from entering the ink cartridge.

When a negative pressure is applied through the nozzle openings of the recording head, the ink absorbed by the porous member 520 flows into the recording head through the through-holes 524 and the through-holes 552 of the ink supply needles 550. When a predetermined amount of ink is consumed away from the porous member 520 and the amount of ink in the porous member 520 decreases, the pressure in the ink chamber 512 exceeds the suction force of the porous member 520 near the communication hole 519, and therefore, air bubbles enter the ink chamber 512 through the communication hole 519. Accordingly, the pressure in the ink chamber 512 increases, and thus the ink flows into the foam chamber 511.

The ink flowing into the foam chamber 511 is absorbed by the porous member 520, and the amount of the ink in the foam chamber 511 is increased. When the ink holding force of the porous material 520 near the communication hole 519 and the pressure in the ink chamber 512 are balanced, the flow of the ink from the ink chamber 512 to the foam chamber 511 is stopped.

The curve shown in fig. 8 represents this process. In the figure, the letter F indicates the pressure value in the porous member 520 of the foam chamber 511, and the letter G indicates the amount of ink in the ink chamber 512. When a predetermined amount of the ink W1 originally contained in the porous member 520 is consumed and the amount of the ink in the porous member 520 decreases to a predetermined value, the pressure in the ink chamber 512 exceeds the ink holding force of the porous member 520 in the vicinity of the communication hole 519 at the predetermined value, so that the ink gradually flows from the ink chamber 512 into the foam chamber 511. This process proceeds until the pressure in the ink chamber 512 and the ink holding force of the porous member 520 in the vicinity of the communication hole 519 return to equilibrium again. As a result, although the amount of ink in the ink chamber 512 is gradually decreasing, the amount of ink in the porous member 520 is kept substantially constant, thereby supplying the recording head ink at a constant rate with a constant pressure difference.

After the recording head consumes a predetermined amount of ink W2, no ink remains in the ink chamber 512, but the amount of ink contained in the porous member 520 is equal to the amount of ink intermittently supplied from the ink chamber to the foam chamber 511. Thus, although there is no ink in the ink chamber 512 to replenish the porous member 520, printing can be continued by the amount of ink absorbed in the porous member 520. After a predetermined amount of ink W3 is consumed during printing, the ink in the porous member 520 will be used up and the ink cartridge will no longer maintain printing.

The amount of ink supplied to the recording head is constant throughout the printing process in which all the ink contained in the ink chamber 512 has been absorbed into the ink-end by the porous member 520. The exhaustion of ink in the ink chamber 512 indicates that the ink in the ink cartridge is about to be exhausted. If a new ink cartridge is inserted to this extent, it is ensured that the ink supply to the recording head is not interrupted.

As described above, the internal space of the ink cartridge of the present invention must be maintained in a negative pressure state during printing. In addition to achieving the above-described gas seal between the ink supply port and the ink supply needle, the ink supply from the ink chamber 512 to the foam chamber 511 must be performed normally in order to ensure that the flow rate of the ink supplied to the recording head is constant. The structure for controlling the ink supply from the ink chamber 512 to the foam chamber 511 will be described below.

Reference is now made to fig. 9, which shows the interface between the foam chamber 511 and the ink chamber 512 of a third embodiment of the present invention. Like structures are denoted by like reference numerals. The main difference between this embodiment and the first embodiment is a stepped portion formed in the bore 519.

A stepped portion 560 is formed in the through-hole 519. The bottom portion 563 of the ink chamber 512 is higher than the bottom portion of the foam material chamber 511, and the step portion 560 is a partition center. A groove 561 communicating the foam chamber and the ink chamber is formed in the lower portion of the stepped portion 560.

The porous member 520 is in contact with the communication hole 519 and is pressed into the step portion 560, so that the portion of the porous member 520 near the communication hole 519 is compressed, and thereby, a desired pressure difference is obtained between the ink chamber 512 and the foam chamber 511 through the communication hole 519. When the amount of ink in the ink chamber 512 decreases to a low value, the groove 561 pools the ink in the ink chamber 512, and then is absorbed by the porous member 520 in the foam chamber 511. Therefore, all the ink in the ink chamber 512 can be supplied to the recording head without waste to perform printing.

Referring now to fig. 10, an ink cartridge constructed in accordance with a fourth embodiment of the present invention is shown. Similarly, like structures are denoted by like reference numerals. The main difference between this embodiment and the first embodiment is the height of the bottom of the respective chambers.

The bottom surface 564 of the ink chamber 512 is higher than the bottom surface of the foam chamber 511, thereby forming a step portion 562. The stepped portion 562 receives a lower portion of the porous member 520. Thus, the portion of the porous member near the passage hole 519 is compressed. A slope 563 may be formed as needed to incline from the ink chamber 512 to the foam chamber 511 to facilitate the transfer of ink. Since the slope 563 allows the ink in the ink chamber 512 to flow to the foam chamber relatively easily in relation to the inclination of the carriage, the head ink can be supplied stably from the ink chamber 512.

Referring now to fig. 11 and 12, there is shown an ink cartridge constructed in accordance with a fifth embodiment of the present invention. Like structures are indicated with like reference numerals. The main difference between this embodiment and the first embodiment is the shape of the through-hole. This embodiment is the same as the embodiment shown in fig. 4 and 5.

A slit 519a shown in fig. 4 and 5 is formed on the surface of the intermediate partition 510 that partitions the foam chamber 511 and the ink chamber 512. The slit 519a is formed on the surface of the partition plate 510 on the side of the foam chamber 511 and communicates with the upper portion of the communication hole 519 of the intermediate partition wall 510 in the corresponding chamber 511, 512. To allow air to enter the foam chambers 511 from the ink chamber 512 and to maintain these chambers in fluid communication, through holes 519b are formed in the lower ends of the slots 519 a. Therefore, the upper portion of the porous member 520 having a smaller capillary force is held in fluid communication with the communication hole 519 through the space formed by the shallow groove 519 a. Thus, air can smoothly displace ink to allow the ink in the ink chamber 512 to flow into the foam chamber 511 in balance, thereby preventing an excess or deficiency in ink supply.

Referring now to fig. 13 and 14, there is shown an ink cartridge constructed in accordance with a sixth embodiment of the present invention. Like structures are denoted by like reference numerals. The main difference is that there is a protrusion into the foam compartment 511.

As shown in fig. 14, a horseshoe-shaped projection 565 is formed on the bottom of the foam chamber 511. The projections 565 obtain a space near the communication hole 519 to allow the ink to easily flow from the ink chamber 512 into the foam chamber 511.

As described above, a central partition 510 separates the foam chamber 511 from the ink chamber 512. As shown in fig. 15 and 16, respectively, in the seventh or eighth embodiment of the monochrome ink cartridge, the ink chamber 571 may be formed so as to surround two or three sides of the foam chamber 570, and the communication hole 573 may be formed in at least one of the walls 572 partitioning the foam chamber 570 and the ink chamber 571. An outlet 574 is provided in the foam chamber 570. The ink cartridge of this structure can store a relatively large amount of ink compared to the volume of the entire ink cartridge. Thus, the user can easily see whether the ink cartridge needs to be replaced due to ink exhaustion, due to the positional relationship of the chambers.

Reference is now made to fig. 17 and 18, which illustrate an ink cartridge for an ink jet printer, constructed in accordance with a ninth embodiment of the invention. This embodiment is similar to the first embodiment, mainly differing in that an elastic O-ring 5300 is employed, and the O-ring 5300 is brought into contact with the circumferential surface of the ink supply needle of the recording head when the ink supply needle is inserted into the ink supply cartridge. However, this ink jet printer produces other problems that have been solved by the first embodiment. When the ink cartridge is loaded onto the carriage and the ink supply needle is inserted into the ink cartridge, a large frictional force is generated to cause additional stress on the recording head and the carriage. Further, the circumferential edge of the O-ring 5300 is supported by the cartridge body 5302. When inserting an ink supply needle into an ink cartridge, if misalignment occurs between the ink cartridge and the ink supply needle of a recording head, it is difficult to mount the ink cartridge. Further, when a three-color ink cartridge having tanks 5304, 5306, and 5308 for containing inks of three colors is integrally formed as shown in fig. 18, if the ink cartridge and any of the ink supply needle axes do not coincide, it is difficult to mount such an ink cartridge on a recording.

It will thus be seen that the objects set forth above, among those made apparent from the preceding description, are efficiently attained and, since certain changes may be made in carrying out the above construction and in the method described without departing from the spirit and scope of the invention, it is intended that all matter contained in the above description and shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

It is also to be understood that the following claims may be interpreted to include the generic and specific features of the invention described herein and the scope of the invention expressed herein.

Claims (3)

1. An ink cartridge for an ink jet recording apparatus, comprising a vent port on a surface of the ink cartridge, the vent port being sealed by a gas-impermeable seal (542) to selectively seal the vent port when the ink cartridge is not in use and to unseal the vent port when the ink cartridge is put into use;

it is characterized in that the preparation method is characterized in that,

a plurality of air release ports (541, 541 ') sealed by the sealing member (542) are provided, each air release port communicating with a groove (540, 540') formed on a surface of the ink cartridge;

the seal comprises a main portion permanently sealing the groove (540, 540', 540 ") and a tongue (545) detachably connected to the main portion (544) by a neck.

2. The ink cartridge for an ink jet recording apparatus according to claim 1, wherein different patterns and colors are printed on said sealing member (542) and said tongue-shaped piece (545), respectively, and said neck portion (543) serves as an interface between said tongue-shaped piece (545) and said main portion (544).

3. The ink cartridge for an ink jet recording apparatus according to claim 1 or 2, wherein said air release opening (541, 541 ', 541 ") is formed at least partially as a curved groove (540, 540', 540") on a surface of said ink cartridge to prevent ink from evaporating.