DE69430589T2 - Liquid container, inkjet cartridge with this liquid container and inkjet apparatus with this inkjet cartridge - Google Patents

Abstract

A liquid accommodating container is connected to an ink jet head and accommodates a liquid supplied to said ink jet head. The container comprises: a partition (215) for dividing said liquid accommodating container into having a first chamber (203) and a second chamber (204), wherein said first chamber (203) is accommodated with a negative pressure generating member (205) and has a supply portion (209) for supplying the liquid to said head and an atmosphere communicating section (206, 208) communicated with an atmospheric air, said second chamber (204) is communicated with said first chamber (203) through said atmosphere communicating section (206, 208) and substantially sealed except said atmosphere communicating section (206, 208), said second chamber (204) accommodating the liquid to be supplied to said first chamber (203), and an area between said supply portion (209) of said first chamber (203) and said atmosphere communicating section (206, 208) having a liquid supply promoting arrangement (217) for promoting the liquid to move.

Description

BACKGROUND OF THE INVENTION Field of the invention

The present invention relates to an ink tank unit for storing ink supplied to an ink jet head unit for discharging the ink, an ink jet cartridge according to the preamble of claim 2, and an ink jet apparatus that performs recording with the cartridge mounted thereon.

Related state of the art

Recording apparatuses which have the features of a printer, a copying machine, a facsimile machine and the like or which can be used as an output device for a complex electronic equipment such as a computer, a word processor or a workstation are constructed so that an image is recorded on a recording medium such as paper or a thin plastic film based on image information. Such recording apparatuses can be classified into an ink jet system, a dot matrix system, a thermal system and a laser beam system depending on the recording method.

A recording apparatus of the ink jet system (an ink jet recording apparatus) performs recording by ejecting ink from a recording device (recording head) onto the recording medium and has the advantages described below. Recording means can be made compact, an image with a high resolution can be recorded at a high speed, an ordinary paper can be used for recording without any special treatments, running costs are low, noise is small due to the shockless process, and a colored image is recorded with ease using colored inks. In particular, a line type recording apparatus using a line type recording means in which a number of ejection ports are arranged in a direction of the sheet width enables recording at a higher speed.

More specifically, a recording device (a recording head) of the ink jet system for ejecting the ink using thermal energy can be manufactured with ease with a structure of liquid channels (ejection openings) in high density by forming electrothermal transducers, electrodes, liquid channel walls and a cover plate as a film on a substrate by a semiconductor manufacturing process such as etching, vapor deposition or sputtering, thereby enabling a further compact structure.

An ink tank for use in the ink jet recording apparatus is required to excellently supply the ink corresponding to an amount of ink to be discharged from the recording head during recording and to prevent leakage of ink from the discharge ports when recording is not performed.

When using a replacement type ink tank, it is necessary that the ink tank is be easily mounted or dismounted without ink leakage occurring, while ensuring supply of ink to the recording head.

One of the ink containers usable for the ink jet recording apparatus has a structure disclosed in Japanese Patent Application Laid-Open No. JP-A-63-87242 (hereinafter referred to as the first conventional example), that is, an ink jet recording cartridge having a plurality of ink ejection ports with a foam member disposed inside the ink container.

In this ink tank, the ink can be stored in a porous medium such as a polyurethane foam which is a foaming member due to a negative pressure caused by a capillary force of the foam, and the ink can be held therein (ink leakage from the ink tank is prevented).

Furthermore, Japanese Patent Application Laid-Open JP-A-2-522 (hereinafter referred to as the second example) discloses an ink-jet recording cartridge provided with a porous member between a main ink tank and a sub-ink tank and between the sub-ink tank and the ink-jet head.

In this invention, by disposing the porous member only in the ink flow path and not containing it in the ink container, the storable amount of ink is increased as compared with the first conventional example. In addition, by providing the second ink container, the ink distribution or the air flow can be regulated when the temperature rises or during recording to stabilize the negative pressure of the recording head.

However, in the first conventional example, since the ink storage portion requires the foam over substantially the entire area thereof, the filling amount of ink is restricted, and a larger amount of ink is not used and is left in the foam, resulting in a problem that the ink utilization efficiency is poor. Another problem arises in that the remaining amount of ink is difficult to detect, and the substantially constant negative pressure is difficult to achieve during the period of ink consumption.

In addition, as is apparent from the first conventional example, in an ink cartridge in the form of a foam inserted into the ink storage portion, depending on the manner of inserting the foam, the corner portion of the foam may deteriorate when the foam is inserted, bringing about uneven pressure distribution of the entire foam, resulting in the possibility that the distribution of the ink in the ink storage portion becomes uneven.

In this case, even if the ink is sufficiently stored, a break may be caused in the ink flow path due to unevenness in the force for generating the negative pressure, resulting in a misfire or possible ink leakage upon impact because the ink is concentrated near the ambient air communication port. Accordingly, a high accuracy is required when inserting the foam into the ink cartridge, resulting in an extreme limitation in manufacturing.

On the other hand, in the second conventional example, since a negative pressure generating element is arranged in the ink flow path when recording is not carried out, the porous medium as a negative pressure generating element is sufficiently impregnated with the ink, causing insufficient generation of a negative pressure with the capillary force of the porous medium, resulting in a problem that ink leakage is likely to occur through the orifices of the ink jet recording head by a slight impact.

In addition, in the technical fields of recording using ink, there is a contact recording method for use in plotters. In this contact recording method, the ink supply is usually made into a recording wire or wick which has an appropriate ink absorption ability and an appropriate ink holding ability like a felt pen.

An example of the ink supply form in the contact recording method described above is set forth in Japanese Utility Model Application Laid-Open No. JP-U 57-16385. This document discloses a recording pen based on the use of a recording wire (a porous ink absorption wire) for recording in contact with the recording medium.

The invention of this document adopts a structure comprising a central chamber with a recording wire, a first wool fiber in contact with the recording wire, and a second wool fiber with a small amount of ink absorbed on the side of the upper ambient air connection opening and less permeable to ink than the first wool fiber, and an ink storage chamber of a closed type from which the ink can be supplied via a connecting hole to each side of the central chamber.

With this structure, the air inside the closed-type ink storage chamber expands due to the increase in the ambient temperature, so that the ink inside the closed-type ink storage chamber flows into the first wool fiber. The ink exceeding the absorbable saturation amount of the first wool fiber soaks the second wool fiber, thereby preventing the ink from flowing out of the recording wire and dripping down.

Furthermore, a groove having a fixed width is provided for causing the air which has expanded to escape into the ambient air communication opening when either of the two closed-type ink storage chambers is filled with only air, the groove extending from the uppermost end to the lowermost end of a side surface different from that of a partition wall between the middle chamber and the closed-type ink storage chamber as disclosed above.

However, in the above-described contact recording pen, no consideration is given to stable generation of negative pressure for preventing ink leakage from the recording unit in the ink jet method involving non-contact recording.

In addition, the consumption of ink from the ink storage chambers on both sides is not necessarily the same, but it should be noted that the ink in one of the ink storage chambers may have been previously may be used up. Some attention is paid to ink leakage from the recording wire due to changes in environmental conditions in this case, but in the field of ink jet recording, some problems such as interruption in the ink flow path or intrusion of air bubbles into the recording section may occur.

In order to solve the above-described problems of the prior art, we, the inventors of the present application, have previously filed an application concerning an ink container suitable for the technical field of ink-jet printing and an ink-jet cartridge, each having the features of the ability to excellently supply the ink in an amount corresponding to the amount ejected from the recording head during printing and the advantage that no ink leakage from the ejection openings occurs when printing is not carried out (see Japanese Patent Application Laid-Open No. JP-A 4-198474 and Japanese Patent Application Laid-Open No. JP-A 4-198681).

It has been found that the basic structure effective for the ink jet characteristics may be a structure comprising a first accommodation chamber which is a negative pressure generating element accommodating portion, the accommodating portion having both an ambient air communication portion for communicating with the atmosphere and accommodating a negative pressure generating element, and a second accommodation chamber which communicates with the first accommodation chamber but is in a substantially closed state and is an ink storage portion for directly storing the ink supplied to the first accommodation chamber (which structure is hereinafter referred to as a structure which is assumed).

Since this structure has a tank structure in which the negative pressure can be made substantially constant for most of the time from the start of use of the head cartridge to the termination thereof, it is possible to provide a replacement type head cartridge and an ink jet head and a printer capable of high speed recording.

Furthermore, in recent years, the ink jet recording technology has been applied not only to a printer but also to the technical field of communication such as a facsimile machine, the field of copying machines to which large paper (paper having a large size) can be applied, and the field of printing on textile products. Due to this trend, a larger capacity of the ink tank for the machine is desirable.

Furthermore, reference is made to DE-A-40 25 319, in which an ink container is disclosed in which a foamed material is housed as a negative pressure generating element. The foamed material is spaced from an inner wall of the ink container with an ambient air connection section. Accordingly, only the side surfaces of the foamed material and not the surface facing the ambient air connection section are in contact with the inner walls of the ink container.

Furthermore, JP-A-04-156 339 discloses an ink cartridge having an ink holding portion divided into a first chamber and a second chamber. The first chamber forms an ink container and the second chamber forms a holding member for holding a porous sponge. The holding member is substantially sealed except for a hole through which the ink in the ink container penetrates the holding member to be infiltrated into the sponge.

SUMMARY OF THE INVENTION

The object of the present invention is to provide an ink container unit with a stabilized ink storage state and an inkjet cartridge and an inkjet apparatus having the same.

The present invention further serves to increase the amount of ink storage in the ink tank unit and improve the application efficiency of the ink.

In addition, the present invention is to uniformly generate the back pressure with respect to an ink jet head unit in an ink jet cartridge having the ink tank unit and to make it substantially constant, and further to facilitate the formation of an ink flow passage from the ink tank unit to the ink jet head unit to obtain a high level of ink supply performance.

Furthermore, the present invention is to improve reliability in preventing leakage of ink through an outlet portion or ambient air communication portion in the ink jet cartridge, particularly against various changes in posture during actual distribution and changes in ambient temperature and humidity.

It is also an aim to provide an inkjet cartridge of the one-piece type which is cost-effective in terms of manufacturing costs.

In order to achieve the above-mentioned object, the invention proposes a structure of an ink container unit according to claim 1 and an ink jet cartridge according to claim 9 and an ink jet apparatus according to claim 12, with further developments being set out in the dependent claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Figs. 1A and 1B show views of a non-claimed example of an inkjet cartridge, wherein Fig. 1A shows a schematic perspective view and Fig. 1B shows a perspective view.

Fig. 2A shows a cross-sectional view of a unit of Fig. 1B as viewed in the direction B of Fig. 1B and Fig. 2B shows a perspective cross-sectional view of the unit of Fig. 2A as viewed from the side of the discharge opening.

Fig. 3 is a view of an ink tank unit according to an embodiment 1 of the present invention.

4A and 4B are views of an ink-jet cartridge according to Embodiment 2 of the present invention, wherein Fig. 4A is a cross-sectional view of the interior along the ink ejection direction and Fig. 4B is a cross-sectional view of the interior along the main scanning direction of the ink-jet cartridge.

Figs. 5A and 5B show views of an inkjet cartridge according to an embodiment 3 of the present invention, wherein Fig. 5A shows a cross-sectional view of the interior along the ink ejection direction and Fig. 5B shows a cross-sectional view of the interior along the main scanning direction of the ink jet cartridge.

Fig. 6 is a view showing the state of holding the ink in the ink cartridge of Figs. 5A and 5B.

7A and 7B are views of an ink-jet cartridge according to Embodiment 4 of the present invention, wherein Fig. 7A is a cross-sectional view of the interior along the ink ejection direction and Fig. 7B is a cross-sectional view of the interior along the main scanning direction of the ink-jet cartridge.

Figs. 8A and 8B show views of an ink tank unit according to a non-claimed example of the present invention, wherein Fig. 8A shows a cross-sectional view of the ink tank unit and

Fig. 8B shows a cross-sectional view of the container of Fig. 8A along the line X-X as a schematic view, wherein, for better illustration of the features of this embodiment, the negative pressure generating element 205 shown in Fig. 8A has been omitted.

Fig. 9A shows a detailed view of a section D of Fig. 8A and Fig. 9B shows a modification of the section D of Fig. 8A.

10A and 10B are views of an ink jet cartridge according to Embodiment 5 of the present invention, wherein Fig. 10A is a cross-sectional view of the interior along the ink ejection direction and Fig. 10B is a Cross-sectional view of the interior along the main scanning direction of the inkjet cartridge.

Fig. 11 shows a schematic perspective view of a portion of Figs. 10A and 10B on an enlarged scale.

12A and 12B are views of an ink-jet cartridge according to Embodiment 6 of the present invention, wherein Fig. 12A is a cross-sectional view of the interior along the ink ejection direction and Fig. 12B is a cross-sectional view of the interior along the main scanning direction of the ink-jet cartridge.

Fig. 13 is a typical perspective view of another inkjet cartridge structure, with a portion shown in cross section.

Fig. 14 shows a schematic cross-sectional view of the inkjet cartridge shown in Fig. 13, viewed from the rear side.

Fig. 15 is an enlarged perspective view of the structure around the periphery of the ambient air communication portion in the ink tank unit of the ink jet cartridge shown in Figs. 13 and 14, with a portion shown in cross section.

Fig. 16 shows a plan view of the structure of an open side of a shown in Fig. 15.

Fig. 17A to 17C show plan views of the opening profile of another ambient air connection section according to the present invention and Fig. 17D shows a cross-sectional view of the internal structure of the ambient air connection section of Fig. 17C.

Fig. 18 is a cross-sectional view showing the internal structure of a first accommodating chamber of the ink tank unit of the ink jet cartridge shown in Figs. 13 to 16.

Fig. 19 showed a cross-sectional view of the ink tank portion shown in Fig. 18 as viewed from the bottom side.

Figs. 20A and 20B are cross-sectional views for explaining the ink movement within the ink tank section shown in Fig. 19, respectively.

Figs. 21A to 21C are cross-sectional views for explaining the mechanism of ink movement within the ink tank unit without a bottom projection 1201.

Fig. 22 is an exploded perspective view of the structure of the ink jet cartridge shown in Figs. 13 to 16, and particularly of the ink tank unit.

Figs. 23A to 23D are cross-sectional views for sequentially explaining the ink pouring process into the ink tank unit of the ink jet cartridge shown in Figs. 13 to 16.

Fig. 24 is an exploded perspective view of the structure of the ink jet cartridge shown in Figs. 13 to 6, and particularly the ink jet head unit as the head portion.

Fig. 25 is a typical perspective view for explaining the vicinity of the ink ejection port of the Fig. 24 shown in an enlarged scale.

Fig. 26 is a side cross-sectional view for explaining the upper end of the ink-jet head unit shown in Fig. 24 on an enlarged scale.

Fig. 27 is a perspective view for explaining the protection of the upper end of the discharge opening portion of the ink jet head unit in the ink jet cartridge shown in Figs. 13 to 16.

Fig. 28 is an exploded perspective view showing the structure of a package applicable to the ink jet cartridge shown in Figs. 13 to 16.

Fig. 29 shows a perspective view of a final package of the inkjet cartridge in which the package shown in Fig. 28 is accommodated.

Fig. 30 is a perspective view of an example of an ink jet apparatus to which an ink jet cartridge of the present invention can be mounted.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will be described in detail below using the drawings. Note that the "negative pressure" referred to in the present invention is a back pressure applied to an ink jet head unit (hereinafter also referred to as a recording head unit) in a direction of ink supply, by which the water column at an ink ejection portion provided on the ink jet head unit is designed to be lower than the ambient pressure.

Figures 1A and 1B show an example, not within the scope of the claims, of an inkjet cartridge that can be mounted on a carriage of an inkjet recording apparatus.

Fig. 1A is an external perspective view of the ink jet cartridge of the present invention, and Fig. 1B is a projection perspective view of an ink tank unit with the recording head unit removed from the ink jet cartridge shown in Fig. 1A, and viewed through one side (corresponding to the bottom side of the ink tank unit, which is an ink reservoir in this embodiment).

Here, reference numeral 200 denotes an ink tank unit (an ink cartridge) which is an ink reservoir for storing the ink, and reference numeral 100 denotes a head unit for performing recording by discharging the ink through the discharging ports 101.

Note that in the present invention, an ink tank unit and a head cartridge that are connected to each other are referred to as an inkjet cartridge.

The ink jet cartridge in this embodiment has a common ink tank unit 200 and a head unit 100 connected to each other as shown in Fig. 1A, and is detachably mounted on a carriage (not shown) of the ink jet recording apparatus with a discharge opening portion 101 facing downward. It is to be noted that in the Ink jet cartridge of this embodiment, the head unit 100 shown in Fig. 1B can be removed from the ink tank unit 200.

Denoted by reference numeral 102 is a wire terminal for both receiving the signal for driving the ink ejection section 101 of the head unit 100 and outputting an ink remaining amount detection signal, and this wire terminal is connected to a wire terminal (not shown) on the side of the ink jet recording apparatus. This wire terminal 102 is provided along the side of the head unit 100 and the ink tank unit 200, that is, along the vertical direction in assembling the carriage, which will be described later.

Reference numeral 103 denotes a pin engagement portion provided on the head unit 100 for engaging a pin provided on the side of the carriage when mounting the ink jet cartridge to the ink jet recording apparatus. This pin engagement portion 103 enables the ink jet head unit 100 to be positioned.

When mounting the ink jet cartridge to the carriage, a lug 201 provided on the ink tank unit 200 is gripped with the ejection portion 100 facing downward to mount the ink jet cartridge at a predetermined position on the carriage. Accordingly, even if the user accidentally touches the ink ejection portion, splashing or adhesion of the ink to the apparatus or mis-ejection will not occur when removing or replacing the ink jet cartridge.

The reference numeral 104 designates an absorption element on the head side, which is responsible for restoring the recovery member for the ink ejection opening portion 101 provided on the ink head unit 100, the details of which will be described below.

The ink tank unit 200 has a negative pressure generating member accommodating portion 203 which is a negative pressure generating chamber and an ink storing portion 204, the negative pressure generating chamber having a porous ink absorbing member 205 which is a negative pressure generating member inserted therein. Between the negative pressure generating member accommodating portion 203 and the ink storing portion 204, an ink communicating portion 206 is provided.

The ink storage section 204 has a pair of electrode pins built therein for use in detecting the remaining amount of ink. The ink storage section 204 is constructed such that the ink storage section and the negative pressure generating element accommodating section are arranged adjacently along a direction vertical to the main scanning direction as a whole by providing a partition section 215 (a partition wall) having an L-shape as viewed from the direction A in Fig. 1B.

Since the ink storage portion 204 is separated by the partition portion with the longitudinal direction of the ink storage portion 204 perpendicular to the main scanning direction along which the ink jet cartridge as a whole moves when ejecting the ink, the size of the ink tank unit is reduced while increasing the ink capacity, and the vibration of the ink inside during Execution of main scanning for recording is suppressed.

It is to be noted that in this embodiment, the ink storage portion has one and a half times or more the volume of the negative pressure generating element accommodating portion, and the larger ink absorbing capacity is achieved by an increase in the ratio of ink storage to the volume of the ink storage portion of the ink container, as compared with the conventional structure of the ink storage portion for storing the ink using only one ink absorbing member.

Referring now to Figs. 2A and 2B, the state in which the ink is stored within the ink jet cartridge will be described. Fig. 2A is a cross-sectional view of a unit of Fig. 1B as viewed from the direction B of Fig. 1B. Fig. 2B is a perspective cross-sectional view of the unit of Fig. 2A as viewed from the side of the discharge opening.

In Fig. 2A, the ink ejection from the head unit is carried out in a downward direction in the drawing, with an ink supply port 209 disposed on the bottom side when the ink jet cartridge is mounted on the ink jet recording apparatus. An ambient air communication port 208 and the ink supply port 209 are disposed on the upper and lower surfaces opposite to each other inside the negative pressure generating member accommodating portion, respectively, with the ink absorbing member 205, which is a negative pressure generating member, disposed therebetween.

The ink supply from the ink storage portion 204 to the negative pressure generating element accommodating portion 203 is carried out in response to pressure changes in ink consumption of the head unit (not shown).

Since the ink is normally located inside the negative pressure generating element accommodating portion, the ink storage portion 204 is in the closed state so that the internal pressure will decrease with the ink supply.

The pressure within the ink storage section 204 decreases with the ink consumption, but since the negative pressure generating element accommodating section is opened to the atmosphere, the gas-liquid interface area within the accommodating section will fall, finally allowing air to enter the ink storage section 204 via the ink communication port 206, bringing about the gas-liquid exchange.

Here, if the clearance of the ink communication portion 206 is too small, the meniscus force is so large that the ink supply from the ink storage portion to the negative pressure generating chamber is not enabled, and this clearance is preferably about 3 mm in consideration of the pore diameter (of substantially 0.1 mm) of a porous member as the ink absorbing member accommodated within the negative pressure generating chamber. In this embodiment, the clearance was 2 mm.

As shown in Figs. 2A and 2B, since the ink supply port 209 is arranged on the bottom side when carrying out the ink ejection, the positional relationship between the ink connection portion 206 and the ink supply port 209 at the time of ink ejection such that the ink supply port 209 has a lower height than the ink communication portion 306 with respect to the direction of gravity.

Accordingly, before the ink level within the negative pressure generating chamber, which falls with the consumption of the ink within the negative pressure generating portion, reaches a position provided at the ink supply port 209, the ink within the ink storage portion 204 is supplied to the negative pressure generating element accommodating portion 203 via the ink connecting portion 206, so that the ink within the ink storage portion can be completely consumed without causing an interruption of the ink flow, thus achieving the improved use efficiency of the ink.

Considering the aspect of interruption of the ink flow, the ink communication portion may be provided anywhere as long as the above-described positional relationship with respect to the ink supply port is satisfied. However, considering the fluctuation of the ink within the ink storage portion, it is preferable that the ink is supplied from the ink storage portion to the negative pressure generating element accommodating portion in a direction perpendicular to the main scanning direction.

In this embodiment, as shown in Figs. 2A and 2B, due to the provision of the ink communication portion on a wall of the partition portion parallel to the main scanning direction, a more preferable form of stable ink supply can be achieved without an influence resulting from the fluctuation of the ink within the ink storage portion.

Fig. 3 shows an example of an ink tank unit according to an embodiment 1. This embodiment offers a structure for further stabilizing the ink storage state within the negative pressure generating element accommodating portion 203 shown in the example of Figs. 1A, 1B, 2A and 2B.

In this embodiment, as shown in Fig. 3, the negative pressure generating member receiving portion 203 is rounded at the four corners 210 inside the negative pressure generating member receiving portion 203. This curved profile enables the absorption member to press evenly at the four corners, so that no chipping or deformation occurs at the edge corners of the ink absorption member 205 due to friction, thereby preventing ink concentration at a locally deformed portion.

Accordingly, the possibility of an ink flow channel being formed in a concentrated ink portion can be further reduced, resulting in a more stable ink distribution so that the ink is stored only in the vicinity of the ink supply port 209 with higher certainty.

Furthermore, the ink absorbing member near the ambient air communication port is not wetted by the ink and has lower wettability (is less likely to be wetted) than if it were wetted by the ink.

This makes it difficult for the ink to migrate within the ink absorption element to the ambient air connection opening, which creates a very stable structure against ink wetting Consequently, the absorption element 205 near the ambient air connection opening can be used as a buffer.

While in this embodiment, a curvature is provided at the four corners, it should be noted that a multi-angle may be designed to eliminate the angle at the four corners to prevent chipping. However, the profile of a rounded shape is more preferable from the viewpoint of insertion accuracy or smooth insertion.

4A and 4B show internal structures of another ink tank unit for use in the ink jet cartridge in the present invention mounted on the ink jet recording apparatus according to an embodiment 2. In this drawing, those parts having the same function as in the previous first embodiment are designated by similar reference numerals.

Fig. 4A shows a cross-sectional view of the interior along the ink ejection direction and Fig. 4B shows a cross-sectional view of the interior along the main scanning direction of the ink jet cartridge. Here, Fig. 4A corresponds to the cross-sectional view De-D of Fig. 4B.

As is apparent from Fig. 4B, an ink storage portion extends on both sides of the negative pressure generating element accommodating portion along a direction crossing the main scanning direction when the ink cartridge is mounted in this cartridge through a partition portion 215, the ink storage portion having a shape similar to a U-shape. In this embodiment, as in the previous first embodiment, the direction of supply of the ink via the ink communication portion 206 from the ink storage portion to the negative pressure generating element accommodating chamber to a longitudinal direction of the ink storage portion, so that the ink storage amount is increased.

As described above, by such a U-shaped structure in which the longitudinal direction of the ink storage portion is perpendicular to the main scanning direction, the fluctuation of the ink due to the movement of the cartridge in the main scanning direction can be suppressed as in the previous first embodiment. In this embodiment, the ink communication portion 206 is provided in the middle portion of the partition portion 215 having the U-shape, that is, on the wall along the main scanning direction of the partition portion 215, thereby further preventing the effects of the ink fluctuation.

5A and 5B show internal structures of another ink tank unit for use in the ink jet cartridge of the present invention as an embodiment 3. In this drawing, those parts having the same functions as those in the previous embodiments are denoted by the same reference numerals.

Fig. 5A shows a cross-sectional view of the interior along the ink ejection direction and Fig. 5B shows a cross-sectional view of the interior along the main scanning direction of the inkjet cartridge.

In this embodiment, as shown in Fig. 5A, an absorption member 205 within the negative pressure generating member accommodating portion 203 is divided into two portions 205-1 and 205-2, and a gap 213 serving as a dome generating portion is so It is provided that a crest can be formed between these sections 205-1 and 205-2.

When the ink reaches this gap portion, a bump is generated there, so that the movement of the ink from the ink absorbing member 305-2 to an ink absorbing member 205-1 is made difficult.

Accordingly, by adopting the structure of this embodiment, the wetting of ink at the ambient air communication port 218 can be prevented with higher reliability.

Fig. 6 shows a case where the ink has been filled into the ink jet cartridge of this embodiment. In this case, even if the expanded ink wets the entire portion 205-2 when reducing the pressure or maintaining a high temperature, the ink is held by the dome forming portion 213 and the ink is made difficult to flow to the portion 205-1, so that the possibility of ink leakage from the ambient air communication port 208 is small.

7A and 7B show internal structures of another ink tank unit for use with an ink jet cartridge of the present invention mounted on the ink jet recording apparatus as an embodiment 4. In this drawing, those parts having the same functions as in the previous embodiment are denoted by the same reference numerals.

Fig. 7A shows a cross-sectional view of the interior along the ink ejection direction and Fig. 7B shows a cross-sectional view of the interior along the main scanning direction of the inkjet cartridge.

In this embodiment, as shown in Fig. 7A, two separate sections 205-3 and 205-4 are provided within the negative pressure generating member accommodating section 203 in a similar manner to the embodiment 3. The difference from the previous embodiment 3 is that a buffer chamber 211 communicating with the ambient air communication port 208 is provided within the negative pressure generating member accommodating section adjacent to the ink absorbing member 205-4 as a negative pressure generating means.

This buffer chamber is secured within the negative pressure generating element accommodating portion by a rib 214 to store the ink overflowing from the ink absorbing member due to the above-described environmental conditions, preventing the ink from reaching the ambient air communication opening portion.

Furthermore, in this embodiment, by arranging the ink absorption member 205-3 between two absorption member abutment ribs 214, the ink flowing into the buffer chamber is prevented from directly reaching the ambient air communication opening 208.

In this embodiment, the reliability of preventing ink leakage is improved due to this buffer chamber.

A structure for preventing ink leakage through the ambient air communication opening portion by changing the shape of accommodating the negative pressure generating element within the negative pressure generating element accommodating portion, which is different than the structure described above is shown below.

8A and 8B show views of an ink tank unit according to an example not falling within the scope of the claims, wherein Fig. 8A shows a cross-sectional view of the ink tank unit and Fig. 8B shows a schematic cross-sectional view of the tank taken along the line X-X, wherein the negative pressure generating element 205 has been omitted for the purpose of better illustrating the features of this embodiment.

Fig. 9A shows a detailed view of a portion P of Fig. 8A. In this embodiment, an ambient air communication passage whose end portion protrudes into the negative pressure generating element receiving portion 203 is used and further a partition wall 219 is provided around the periphery of the ambient air communication passage as shown in Figs. 8A to 9A.

Here, if it is assumed that the height of the protruding ambient air communication opening portion 218 = c, the height of the partition wall 219 which is an annular projection provided on its periphery is made at 2c or larger, a gap 211 as a buffer chamber is formed between the negative pressure generating member (ink absorbing member) 205 and a projection 218 of the ambient air communication opening, thereby preventing the leakage of ink through the ambient air communication opening portion.

Furthermore, the annular outer partition wall 219 is spaced from a projecting tubular end portion 218 of the ambient air communication opening so as not to be in contact therewith, and even if leakage of ink from the negative pressure generating element 205 occurs, no ink enters the ambient air communication opening portion 218 along the partition wall 219.

However, in this case, it is desirable that the distance provided between both projections is set to be sufficiently large not to cause a capillary phenomenon, thereby reducing the possibility that the ink adhering to the partition wall reaches an opening portion at the end of the ambient air communication opening portion.

It should be obvious that the ambient air communication opening portion within the negative pressure generating element accommodating portion has a triple structure with an outwardly increasing height of the partition wall as shown in Fig. 9B.

If it is assumed that the length of the innermost projection or a projection portion 218 of the ambient air communication opening portion = c, the length of the outermost annular projection 220 is made 2c or longer (for example, 3c). This further increases the reliability of preventing ink leakage through the ambient air communication opening.

In addition to the examples described above, modifications such as a quadruple or multiple structure may be made to improve the reliability in preventing ink leakage.

In this example, the ambient air communication opening portion is located within the negative pressure element accommodating portion of the ink tank unit above the structure, thereby forming a space as the buffer chamber between the ink absorbing member and the surface provided with the ambient air communication opening. is formed, and further preventing the ink from the partition wall forming the buffer chamber from reaching the opening portion at the end of the ambient air communication opening portion to increase the reliability in preventing the leakage of ink through the ambient air communication opening portion.

Furthermore, even if the ink enters the inside of the annular projection, the ink is caught before reaching the innermost projection of the ambient air communication port, in whatever position the ink jet cartridge is set therein, since the annular projections are spaced apart, thereby increasing the reliability of preventing ink leakage.

In the examples described above, an ink container unit has been proposed which comprises a negative pressure generating member accommodating portion (an ink absorbing member accommodating portion) having an ink supply port communicating with the recording head, the accommodating portion accommodating a negative pressure generating member (an ink absorbing member), and an ink storage portion adjacent to the absorbing member accommodating portion and communicating therewith via an ink communicating portion on its bottom side to simultaneously realize improved utilization efficiency of the ink and accurate generation of a negative pressure force.

In the above-described structure, the ink supply from the ink storage portion to the negative pressure generating element accommodating portion is designed to be such a process that the ink within the ink storage portion 204 is supplied to the Negative pressure generating element accommodating portion 203 when the ink level in the vicinity of the partition portion 215 decreases at least to the ink connecting portion 206 of the partition portion 215 due to consumption of the ink within the negative pressure generating portion.

The ink level in the negative pressure generating member accommodating portion necessarily decreases because the ink communication portion communicating with the ink storage portion is located at the bottom of the partition portion 215. However, in practice, it is difficult to make the pressing force of the absorbing member received within the negative pressure generating member accommodating portion uniform, and the decreasing ink level is not necessarily uniform.

On the other hand, since the negative pressure generating member has a function of holding the ink, the ink level within the negative pressure generating member accommodating portion will again rise when the ink is supplied from the ink storage portion. Accordingly, there is a possibility that the amount held above the ink supply port 209 within the negative pressure generating member accommodating portion is not always constant.

The negative pressure generated by the ink absorbing member is possibly influenced by the weight of the ink itself within the negative pressure generating member accommodating portion. In particular, when the ink supply opening portion 209 for connection to the recording head is provided at the bottom portion of the negative pressure generating member accommodating portion as in the As in the previous example, the variation in the amount of ink will cause a variation in the negative pressure.

In this case, by increasing the clearance of the ink connecting portion between both the accommodating portions, the ink level cannot be adjusted. Since the increased clearance prevents the formation of the ink dome in the ink connecting portion, the ink is excessively supplied to the absorbing member accommodating portion, causing an excessive reduction in the negative pressure within the absorbing member, resulting in a risk that ink leakage may occur.

In the embodiment described below, a structure for improving the stability of this negative pressure is proposed.

10A and 10B are views that best illustrate the features of an ink jet cartridge according to an embodiment 5. In this drawing, those elements that have the same functions as in the previous embodiment are denoted by the same reference numerals.

Fig. 10A shows a cross-sectional view of the interior of an ink tank unit connected to an ink-jet head unit, along the ink ejection direction. Fig. 10B shows a cross-sectional view of the interior of the ink-jet cartridge along the main scanning direction.

Here, reference numeral 105 denotes an ink connector for introducing the ink within the ink jet head unit, and reference numeral 106 denotes a filter which is attached to the End portion of the ink connecting member 105 is provided for preventing the inflow of fine dirt particles into the inkjet head.

In Figs. 10A to 11, a represents the height of the ink absorbing member receiving portion and h represents the height of the top of a groove portion with respect to the filter surface arranged at the end portion of the ink connecting member.

This embodiment differs from the above-described first embodiment in that the wide groove portion 216 (the concavity) is provided at the upper portion of the ink communication portion so that the lower portion or an end of the negative pressure generating element accommodating portion at a partition wall 215 in the partition portion can communicate with the ink communication portion 206. By providing this groove portion 216, the inlet passage of the air into the ink storage portion can be secured with ease during the gas-liquid exchange resulting from the consumption of the ink.

Here, the gas-liquid exchange is effected via the end portion opposite to the portion leading to the ink communication portion of the groove portion. In this embodiment, the groove portion at the end of the gas-liquid exchange side has a smaller depth as it leads farther from the ink communication portion. This facilitates the introduction of the air into the groove portion.

In this embodiment, the negative pressure state within the negative pressure generating element receiving portion can be controlled by the Negative pressure generating force (capillary force) of the ink absorbing member 205 which is the negative pressure generating member, and the amount of holding the ink within the ink absorbing member 205 seated above the ink supply opening portion 209 are determined as shown in Figs. 8A and 8B.

In this case, the negative pressure generating force within the negative pressure generating element accommodating portion is set to a back pressure of DmmAq or greater in a reverse direction to the ink supply direction in the ink supply port, assuming that the distance between the ink supply port side and the ejection port side of the recording head is Dmm, to prevent the ink from leaking through the ejection ports of the recording head.

On the other hand, the upper limit of the negative pressure generating force must be determined in view of the ink consumption in the ink supply or the reduced printing density due to insufficient ink supply. In this embodiment, D = 200 mm and the negative pressure generating force within the negative pressure generating element accommodating portion is set in the range of 20 mm Aq to 40 mm Aq.

As a means for controlling the negative pressure within the negative pressure generating element accommodating section, a method for adjusting the height h of the gas-liquid exchange groove section 216 is adopted in this embodiment, which is described above. By changing the height of this groove section, the position of the gas-liquid interface within the negative pressure generating element accommodating section can be adjusted. to achieve the stability of the negative pressure.

The positional relationship between the groove portion and the filter surface in this embodiment is such that the distances from the negative pressure generating chamber bottom portion to the filter surface of the ink supply port and to the partition wall end portion at the upper portion of the ink communication portion are identical, as shown in Figs. 10A and 10B.

The distance h up to the top of the groove portion with respect to the filter surface is set to 5 mm, and the gas-liquid interface (ink level) from the ink storage portion to the remaining ink in the absorption member accommodation portion is maintained at a position of about 5 mm or less with respect to the filter surface within the absorption member accommodation portion. By setting the position of the gas-liquid interface to less than about 5 mm, the negative pressure is generated within the above-described state range. Note that the height a of the negative pressure generating member accommodation portion is 48 mm in this embodiment.

Accordingly, by adopting the structure with a groove portion provided as proposed in this embodiment, the ink supply from the ink storage portion in the ink communication portion to the negative pressure generating element accommodating portion can be kept stable and the ink level (the gas-liquid interface) within the negative pressure generating element accommodating portion can be kept substantially constant. Thereby, the The amount of ink accommodated within the negative pressure generating element accommodating portion is substantially constant, and the variation in ink supply or negative pressure which may affect the recording quality can be suppressed.

In this embodiment, as described above, since the filter surface of the ink connector end portion protrudes from the bottom surface of the negative pressure generating chamber, the ink absorbing member is compressed in the vicinity of the ink supply port to concentrate the ink to improve the ink supply performance to the ink jet head unit.

It should be noted that the height of the groove section above the filter surface is set at a minimum, with 1 mm above the filter surface being preferred, and 2 mm above being even more preferable.

The reason for this is that the uneven distribution of the compression of the ink absorbing member may be caused by the state of insertion of the ink absorbing member, resulting in a possibility that the ink level locally fluctuates within the negative pressure generating member accommodating portion, thereby causing ink interruption.

Accordingly, by providing a groove portion as proposed in this embodiment at the upper portion of the ink communication portion, the ink level within the absorbing member accommodating portion is maintained at an appropriate position when supplying the ink from the ink storage portion to the absorbing member accommodating portion until the ink is used up, so that the static negative pressure within the absorption element can be generated more stably.

In the above-described example with reference to Figs. 1A, 1B, 2A and 2B, there is a possibility that the ink level fluctuates with the consumption of the ink, as already pointed out. The bottom surface of the ink storage section and that of the absorption member accommodating section are coplanar, whereby the changes in the ink level not only generate the above-described changes in the negative pressure, but also possibly interrupt the ink flow channel within the absorption member when the ink is supplied from the ink storage section to the absorption member accommodating section as in the above-mentioned example in which the ink supply port is provided on the bottom surface of the negative pressure generating member accommodating section.

In this case, since such a problem cannot be solved by increasing the gap of the ink communication portion between both the receiving portions as described above, the structure described below is adopted in Embodiment 6 for realizing further stabilization of the ink supply.

The structure of this embodiment is shown in Figs. 12A and 12B. In the drawings, those elements having the same functions as in the previous embodiment have the same reference numerals.

Fig. 12A shows a cross-sectional view of the interior along the ink ejection direction and Fig. 12B shows a Cross-sectional view of the interior of an inkjet cartridge along the main scanning direction.

As shown in Fig. 12B, a recessed portion 217 (a concavity) is provided in the bottom portion of the negative pressure generating element accommodating portion so that the bottom portion of the negative pressure generating element accommodating portion is lower than the bottom portion of the negative pressure generating element accommodating portion when the ink jet cartridge is mounted. This recessed portion 217 is provided to have a depth b in the range from the vicinity of the ink communicating portion 206 to the vicinity of the ink supply port 209 as shown in Fig. 12BA.

By providing this recessed portion, the ink flow channel within the negative pressure generating element accommodating portion can be secured in the height direction without preventing the formation of a dome in the gas-liquid exchange in the ink communicating portion.

It should be noted that the depth b of the recessed portion determines the formation width of the ink flow channel, and a larger value of b leads to a higher effect and higher reliability of preventing ink interruption.

The structure of this embodiment, in addition to the structure with a groove portion provided on the partition wall as described above in the example shown in Figs. 1A, 1B, 2A and 2B, enables the stable Creating negative pressure or securing the ink flow channel, resulting in more stable ink delivery.

Other embodiments enabling improvement in ink supply performance and reliability of ink leakage prevention are described below with reference to the drawings.

13 and 14 show an embodiment of the present invention of an ink jet cartridge having a head unit and an ink tank unit connected to each other, wherein Fig. 13 shows a typical perspective view of the structure of the ink jet cartridge of this embodiment partially in cross section, and Fig. 14 shows a schematic cross-sectional view of the head shown in Fig. 13 as viewed from its rear side.

As shown in Fig. 13, an ink container unit 1000 in this embodiment has a communication port portion 1101 as an ink supply port for supplying the ink to an ink jet head unit 2000 as a head portion on the bottom side of the ink container unit 1000. The ink container unit essentially comprises: a first accommodation chamber 1100 which is a negative pressure generating element accommodating portion having an ambient air communication portion 1150 for accommodating a negative pressure generating element 1102, a second accommodation chamber 1200 arranged behind it and communicating with the bottom surface of the first accommodation chamber 1100 through a very small communication portion 1300 as an ink communication portion and for storing the ink to be supplied to the first accommodation chamber 1100, and a side second Accommodation chamber 1250 for connection at partition walls 1251a and 1251b with a connection portion larger than the very small connection portion 1300 to the second accommodation chamber 1200 arranged behind. In this embodiment, an L-shaped ink storage portion is formed by the second accommodation chamber 1200 arranged behind and the lateral second accommodation chamber 1250 as in the previously described embodiment.

Here, the negative pressure generating element 1102 is accommodated in the first accommodation chamber 1100 in a range of two-thirds from the bottom surface of the first accommodation chamber.

The negative pressure generating element restricting ribs 1103a, 1103b and 1103c are arranged at three locations on a cover of the first accommodation chamber 1100 so that the volume in which the negative pressure generating element 1102 is not accommodated can be forcibly kept free, thereby suppressing excessive insertion of the negative pressure generating element 1102.

By the three limiting ribs described above, the area of the first accommodation chamber formed therebetween consists of an air layer 1104, and the ambient air communication section 1150 is arranged in this air layer. Here, it is important that an opening section 1152 on the first accommodation chamber side of the ambient air communication section is located at a position which is spaced at a fixed distance from the negative pressure generating element 1102 at all times. As a result of investigations, the inventors of the present invention have found that in view of the fluctuation in the insertion of the negative pressure generating element 1102, the pressure stress of the restricting ribs 1103 or the softening deformation of the restricting ribs 1103 due to a rise in temperature, preferably the above-described clearance is in a range of 3 mm to 5 mm. Here, the reason for setting the upper limit is that securing a sufficient distance from the cover of the first accommodation chamber to the opening portion 1152 of the first accommodation chamber is important in obtaining a safety factor against ink leakage at an inverted position (as will be explained in detail later). Note that the direction of arrow E in Fig. 13 indicates the scanning direction of the head according to this embodiment, and the direction of arrow F points in the ink ejection direction from the head.

Fig. 15 is an enlarged perspective cross-sectional view of the ambient air communication portion and its vicinity in this embodiment. Fig. 15 is a view of an opening portion 1151 of the ambient air communication port shown in Fig. 14 as viewed from above. The ambient air communication portion 1150 basically comprises a barrel portion 1150a extending from the inside of the first accommodation chamber 1100 to its wall portion and having its dead center near the outside of the wall portion as shown in Fig. 15, and an opening portion (ambient air communication port opening portion 1151) divided into a plurality (three in this embodiment) branches from the dead center portion of the barrel portion 1150a. This opening portion is provided on the outside of a casing for the ink tank unit 1000. It should be noted that the opposite end of the opening portion 1151 of the ambient air communication port of the cylinder portion 1150a corresponds to the opening portion 1152 the first accommodation chamber. This ambient air communication portion 1150 is a hole for introducing the outside air into the ink tank unit 1000 to obtain a pressure equal to the outside pressure during printing, but it is preferable that it is slender and long in view of the evaporation of the ink. However, such a shape has been contrary to its function from the viewpoint of process control of the mold and the mold cycle in injection molding the container with resin in the manufacturing process of the ink tank unit 1000. As a result, the evaporation of the ink may be allowed to a certain extent, or the part around the ambient air communication portion may be formed of a variety of members to achieve this goal. The former result involves a problem particularly in the color recording head in that the colored ink may vary between the starting time of use and the ending time, while the latter result involves an increased number of processes due to the complex manufacturing process with an increased number of parts, resulting in a costly recording head.

In view of the above-described problem, the inventors of the present invention have proposed a structure for holding a slender pin of the mold which is not swung when injection molding a slender and long ambient air communication port, as well as for effecting integrality (integral molding) of complex-shaped parts and preventing foreign matter from directly entering the interior of the ink container through the opening portion of the ambient air communication portion arranged on the surface of the product.

In Fig. 15, the opening portion 1151 of the ambient air communication opening is constructed so that the pin on the sliding side is received with three claws provided on the fixed side of the cavity of the mold, whereby the slender pin can be positioned and formed with high accuracy. In this embodiment, the ambient air communication hole having an inner diameter of 1 mm and a length of 10 mm can be manufactured in about 20 seconds in a usual molding cycle. In this embodiment, the opening portion 1151 of the ambient air communication hole is divided into three portions, but it is not limited to these three, the opening portion may also be divided into two or four portions with two or four claws (see Figs. 17A and 17B). Regarding the positional relationship between the gate position and the ambient air communication position, a through hole may be shaped like a crank by providing a claw at a location on the side where the sliding pin is held so as not to tilt due to the pressure of the flowing resin (see Fig. 17C). Needless to say, the ink jet cartridge can be used in the foregoing embodiment, but it is not limited to the container unit in this embodiment and is also effective in an integral container or a replacement type container in which the negative pressure generating element is substantially entirely housed within the ink storage portion.

The surface of the opening portion 1151 of the ambient air communication port is open to a groove 1153 which is depressed 1 mm below a label adhesive side 1105 forming a part of the outer surface of the ink tank unit 1000 which is 0.2 mm or more below the surface of the container, this groove 1153 being covered with a plastic film (for example, a label) (not shown) having an adhesive layer. and the opening is connected to the ambient air through the groove extending beyond the film.

The groove 1153 is formed with a length longer than the film width on both sides of the film. When the film is adhered at the normal position, two opening portions to the ambient air are provided on the two sides of the film. Even if the film deviates to either side, one opening portion to the ambient air can be secured at all times. An object of covering the opening portion 1151 of the ambient air communication portion with the film is mostly the external appearance, but another object is to secure the overall extent of the ambient air communication opening and to suppress evaporation. The plastic film may be a laminate of synthetic paper UPO and a polypropylene film or a film having a printing layer interposed between the above-mentioned two layers and on which an adhesive layer has been applied.

Referring now to Fig. 18, the generation of the negative pressure in the ink tank unit of this embodiment will be described.

The state of the negative pressure in the first accommodation chamber 1100 is determined by the negative pressure generating force of the negative pressure generating element 1102 and the holding amount of the ink within the negative pressure generating element 1102 provided above the connection side of the ink ejection portion, as described above. In addition, the negative pressure within the first accommodation chamber 1100 must be -D mm Aq or more, assuming that the distance between the connection side of the ink ejection portion and the head ejection opening side is D mm, the leakage of ink through the head ejection ports has been taken into account.

In addition, the upper limit of the negative pressure must be determined by taking into account the ink consumption in the ink supply, the reduced print density in the insufficient supply, and a disturbance in the image. In this embodiment, D is 20 mm, and the negative pressure of the negative pressure generating element 1102 is set within the range of -20 mm water column to -40 mm water column.

As a means for controlling the negative pressure of the first accommodation chamber 1100, there is a manner of adjusting the height h of an auxiliary structure 1110 for gas-liquid exchange with a structure in which, on the wall surface of the first accommodation chamber 1100 of the partition wall 1100a for separating between the first accommodation chamber 1100 and the second accommodation chamber 1200, the upper portion of the very small connecting portion 1300 is formed thin, or with a structure including a groove provided on the wall surface of the partition wall 1100a as described above. Using this structure, the air moves from the first accommodation chamber 1100 to the second accommodation chamber 1100 arranged behind it in the closed state, while at the same time the ink is supplied from the second accommodation chamber to the negative pressure generating pressure element 1200 within the first accommodation chamber 1100, so that the ink liquid level can be maintained below the upper part of the auxiliary structure 1110 for gas-liquid exchange. Accordingly, by changing the upper portion of the auxiliary structure 1110 for gas-liquid exchange, the gas-liquid interface within the first accommodation chamber 1100 at any height.

In this embodiment, assuming that the height h from the connecting surface of the ink ejection portion to the upper portion of the auxiliary structure for gas-liquid exchange is 5 mm, the ink liquid level in the gas-liquid exchange during recording and during non-recording time (including a standby state) is always kept in the range of 2 mm to 5 mm above the connecting surface of the ink ejection portion, whereby the stable state can be achieved until all the ink within the rear second accommodation chamber 1200 and the side second accommodation chamber 1250 is used up.

In this embodiment, an auxiliary structure 1120 for ink supply having a portion slightly lower than the bottom surface of the chamber is provided on the bottom surface of the first accommodation chamber 1100. The structure of the auxiliary structure 1120 for ink supply will be described in detail below. This structure is arranged for the purpose of eliminating the interruption of ink supply from the very small connecting portion 1300 to the connecting surface of the ink ejection portion, but it is an extremely effective means when the appropriate negative pressure cannot be obtained solely by adjusting the height of the auxiliary structure 1110 for gas-liquid exchange. For example, this structure is effective when the connecting port portion 1101 with the ink jet head unit 2000 is located on the bottom side of the ink container portion 1100 or when the distance from the very small connecting portion 1300 to the connection opening portion 1101 is large, or both, as is the case in the example shown in Figs. 2A and 2B.

In this embodiment, the depth of the ink supply auxiliary structure 1120 is 1.5 mm lower than the bottom surface of the rear second accommodation chamber 1200 and the side second accommodation chamber 1250 or the bottom surface of the very small connecting portion 1300, thereby solving all of the above-mentioned problems.

The auxiliary structure 1120 for ink supply in this embodiment has a uniformly lower bottom surface, but it may have some slits with uniform depth. In addition, in the ink tank unit having a structure in which the communication opening portion 1101 faces the partition wall 1100a having the very small communication portion 1300, it was confirmed that the same effects can be achieved by arranging a projection-like rib.

Referring now to Figs. 19 to 21C, the occurrence of ink through the ambient air communication port of the ink tank unit will be described.

The ink jet cartridge having the structure of this embodiment can prevent evaporation during distribution and is arranged in such a packaged state that the head is not damaged and the function is not impaired.

In addition, the discharge port side which most affects the head characteristics is covered with a protective sealing tape, but the opening portion of the ambient air communication portion leading to the inside of the inkjet cartridge is not sealed. In the case of a replacement type ink cartridge, only the connection opening portion to the head portion and the ambient air connection opening are provided, and these two opening portions can be sealed with a sealing tape.

However, in the case of a head of the integral type, when all the opening portions are closed to prevent the occurrence of ink, the internal pressure caused by the changes in the environmental conditions may cause leakage of ink into the opening portion and through the connecting portion between the ejection portion and the reservoir portion.

In addition, the ink ejection port cannot be completely sealed by a sealing tape due to its structure. For this reason, in the one-piece type inkjet cartridge, the ambient air connection port is opened inside the sales package.

Therefore, in the ink container unit having the first accommodating chamber and the second accommodating chamber, when the head cartridge is ejected in the device position, the ambient air communication port is arranged to face upward, whereby no ink leakage occurs, but in another position, particularly in the reverse position, the ink in the second accommodating chamber may flow into the air layer 1104, sometimes causing leakage through the ambient air communication port and splashing into the package.

In this embodiment, as a means for preventing leakage of ink within the ink tank unit through the ambient air communication portion at all during of distribution possible positions as described above, and under ambient temperature conditions or ambient humidity conditions or even under complicated conditions, four vertical edge line portions 1115a, 1115b, 1115c and 1115d contacted by the negative pressure generating member 1102 of the first accommodation chamber 1100 are curved with a radius of curvature R of 2 mm so that the negative pressure generating member 1102 can press the absorbing member evenly at the four corners so as not to cause peeling or deformation, in which case a gap is generated and inflow or concentration of the ink is caused at the corner portion.

On the other hand, five vertical edge line portions 1215a, 1215b, 1215c, 1215d and 1215e of the rear second accommodation chamber 1200 and the side second accommodation chamber 1250 except for the minute connecting portion 1300 are curved with a radius of curvature of 2 mm, and a projection 1201 having a height of 2 mm and a width of 14 mm is arranged in the vicinity of the minute connecting portion 1300 on the bottom surface of the rear second accommodation chamber 1200. The necessity for providing a curvature to each edge line portion of the second accommodation chambers and the projection on the bottom surface as described above is based on the results of the experiments conducted by the inventors of the present invention as described below.

Figs. 21A to 21C show cross-sectional views of an ink jet cartridge without a vertical edge line portion 1215a to 1215e and the bottom projection 1201 in the two second accommodation chambers 1200 and 1250. When the ink jet cartridge is in the inverted state with the discharge port facing upward and under high temperature (60°C to 80°C) distribution conditions, the ink filled within the second accommodation chamber will expand due to the heat and enter the negative pressure generating member 1102 through the minute communication portion 1300. At this time, the internal pressure is relieved through the ambient air communication port. Thereafter, the gas-liquid exchange occurs through the ambient air communication port and the minute communication portion 1300, so that the air is introduced into the second accommodation chamber 1215 (see Fig. 21A).

Furthermore, the gas-liquid exchange between the ink within the second accommodation chamber and the air within the first accommodation chamber 1200 occurs even when the ink liquid level falls below the level of the very small connecting portion 1300 of the partition wall 1100a. This is because the edge portions of the five vertical edge lines perpendicular to the bottom surface (upper surface in this drawing) within the second accommodation chamber 1250 pull the ink upward due to the capillary force, and the expanded air within the second accommodation chamber 1250 assists this (see Fig. 21B).

Furthermore, the air layer inside the second accommodation chamber 1250 contains the evaporated water components of the ink, causing a phenomenon in which the water vapor in the supersaturated state wets the bottom surface of the second accommodation chamber (upper side in this drawing). Particularly, when a temperature change occurs, this state will occur more remarkably. As a result, gradually accumulates condensate drops which become larger water drops, part of which will drop into the ink and the other part of which will be sucked through the very small communication portion into the negative pressure generating element 1102. Due to this circumstance and due to the drawing up of the ink into the edge line portions as mentioned above due to the capillary force, the ink moving in the first accommodation chamber is received in the air layer 1104 and starts to leak out through the ambient air communication opening when the ink liquid level exceeds the height of the ambient air communication portion (see Fig. 21C).

In contrast, Figs. 20A and 20B show cross-sectional views of an ink jet cartridge according to this embodiment, in which five vertical edge line portions perpendicular to the bottom surface of the second accommodating chamber are curved and a projection 1201 is arranged in the vicinity of the minute connecting portion 1300. The discharge opening faces upward.

In Figs. 20A and 20B, when a high temperature condition is present in the initial state, the volume of the ink will expand to enter the negative pressure generating element 1102. Due to this and due to the gas-liquid exchange, the ink is moved from the second accommodation chamber 1200 to the first accommodation chamber 1100 in the amount corresponding to the height of the very small connecting portion 1300 (see Fig. 20A).

However, since the vertical edge line portions of the second accommodation chamber 1200 are curved, there is no capillary force applied to the ink, which also does not Movement of the ink while it is still in its initial state.

In addition, the water drops wetting the bottom surface (on the upper surface in this drawing) of the second accommodation chamber 1200 are blocked by the protrusion 1201 provided near the very small communication portion 1300 and are not absorbed by the negative pressure generating member 1102 and are dropped into the ink within the second accommodation chamber 1200. Accordingly, the ink is not moved beyond a certain amount, thereby preventing the ink from leaking through the ambient air communication port (see Fig. 20B).

Here, it is necessary that the height H of the connecting portion in the ambient air communication port (see Fig. 18) is sufficiently high so that when the ink flows into the air layer 1104, the ink cannot flow into the opening portion of the first accommodating chamber of the ambient air communication port. In this embodiment, H = 10 mm was obtained by multiplying the ink liquid level corresponding to the maximum flowable amount of ink from the second accommodating chamber 1200 in the inverted state by a safety factor of 2.

Referring to Fig. 22 and Figs. 23A to 23D, a manufacturing process of the ink tank unit of this embodiment will be described below.

In Fig. 22, reference numeral 1600 denotes a housing of the ink container unit, reference numeral 1102 denotes a negative pressure generating element, and reference numeral 1400 denotes a container lid. 1202a and 1202b denote electrode posts for detecting the remaining amount of ink, and 1203 and 1204 denote contact members extending from each electrode post to the electrode disposed in the ink ejection portion. 1206 denotes an ink pouring port, and 1205 denotes an ink pouring port plug. The ink tank unit casing 1600 is formed by integral molding of resin. Inside the first accommodating chamber 1100 of the ink tank unit casing 1600, there is housed a negative pressure generating member 1102 which is inserted after being compressed from both sides in the direction of the arrow of Figs. 21A to 21C. The negative pressure generating member 1102 is compressed by one-third to one-quarter when accommodated.

Thereafter, the container lid 1400 is connected to the casing 1600 of the ink container unit, but this connection is effected by welding in view of the airtightness of the connection and productivity. In particular, ultrasonic welding is a preferable measure from the viewpoint of both reliability and productivity. Thereafter, the electrode pins 1202a and 1200b are urged into the vicinity of the bottom side of the side second accommodation chamber 1250 of the container casing 1600 via the contact members 1203 and 1204 and welded thereto.

The ink is poured into the thus assembled ink container unit 1000 through the ink pouring port opened in the container lid 1400. The pouring process is shown in Figs. 23A to 23D. When pouring in the ink, the ink is poured under pressure in a fixed amount in the inverted state, at in which the very small connecting portion is located at the uppermost portion, an inner diameter of the ink supply port is 1.5 mm, and the pouring speed is about 4 cm³/sec, as shown in Fig. 23A, whereby excellent pouring conditions without bubble generation can be achieved. The pouring of the ink is stopped at the time when the second accommodating chamber is filled with the ink to cause the ink to flow from the very small connecting portion into the negative pressure generating member, and the supply port portion is pulled out at the upper end and plugged at substantially the same time (first pouring) (see Figs. 23B and 23C). Thereafter, at a position where the opening of the ink ejection portion is located at the uppermost position, the ink is poured therein under pressure in a fixed amount, thereby completing the pouring (second pouring).

This second pouring is carried out through a nozzle having a diameter of 1.5 mm and a pouring rate of about 4 cc/s by inserting it by an amount by which the delivery port contacts the negative pressure generating port 1102 as in the first pouring, so that the ink is evenly distributed.

Finally, a label is glued to the outside surface of the container, completing the ink tank unit.

The inkjet unit and its assembly procedure are described below.

Fig. 24 is an exploded perspective view showing the structure of an ink jet unit 2000 of this embodiment. Here, reference numeral 2100 denotes a substrate (a heater board) having elements which are arranged to generate heat energy which is an ink ejection energy, and 2400 is a cover plate (grooved cover plate) which has both grooves for forming liquid flow channels corresponding to the elements and a member having the ink ejection openings formed corresponding to the liquid flow channels. 2200 is a circuit substrate for supplying electric power to the heater board 2100, and 2300 is a base plate which serves as the reference in packaging the ink ejection section, 2500 is a compression spring for applying a uniform pressure (a linear pressure) in the vicinity of the ejection openings of the ejection section by urging the cover plate 2400 and the heater board 2100 into close contact with each other.

Reference numeral 2600 denotes a holder having a flow channel inside for supplying the ink from the ink tank unit to the ink jet head unit, and a filter 2700 for preventing the ingress of foreign matter is welded to the connecting surface with the ink tank of the ink connecting portion 2600 of the holder.

In Fig. 24, an adhesive having a predetermined thickness is applied to a predetermined area 2405 near the front end face 2300a on the surface of a support device 2300, and on the surface to which the adhesive has been applied, a heating board 2100 is secured by the adhesive such that its front end face 2100a and a front end face 2300a of the support device 2300 are aligned. The cover plate 2400 is arranged on this heating board 2100 by temporarily bonding such that an opening plate 2400a is provided in front of the two front end faces 2100a and 2300a of the heater board 2100 and the support means 2300 as shown in Fig. 24. Here, in Fig. 25, reference numeral 2105 denotes an ejection heater which is an electrothermal transducer provided at a predetermined position on the heater board 2100. In addition, reference numerals 2411 and 2412 denote ink flow channel grooves formed on the cover plate 2400, and reference numerals 2421 and 2422 denote ejection orifices bored by excimer laser on the orifice plate 2400a of the cover plate 2400.

In this way, with the cover plate 2400 temporarily connected to the heater board 2100, the heater board 2100 and the cover plate 2400 are located on the support member 2300 as shown in Fig. 26, and further, a holder 2600 that covers and protects the wire substrate 2200 is arranged thereon.

An assembling method of the ink jet head unit of the present invention will be described below.

After the heater board 2100 is bonded to the support 2300 by means of an adhesive (a silicone type adhesive SE 4400 manufactured by Toray) having a thickness of 10 to 30 µm, the connection to the wire substrate 2200 is carried out by wire bonding with an aluminum wire. The ink ejection ports of the cover plate 2400 and the ejection heaters 2105 of the heater board are aligned with each other and then temporarily secured by applying an ultraviolet ray-curable adhesive (TB 3006 B manufactured by Three Bond) to both end portions of the cover plate 2400. Thereafter, for the connection between the cover plate 2400 and the heater board 2100, a spring 2500 is used for concentrated pressing on the ejection ports and the The spring 2500 has spring legs 2500a and 2500b on both sides and is secured by engagement with the heater board 2100. Thereafter, the cover plate 2400 is placed on the heater boards 2100 and 2200 and the support 2300. The holder 2600 has a pair of foot portions 2600e which are arranged on both sides of the cover plate 2400 and which are inserted through a pair of holes 2300b in the support 2300 so that the front ends of the foot portions 2400e protrude beyond the rear of the support 2300.

Finally, a silicone sealant (TSE 399 BC Toshiba Silicon) is poured from the upper portion of the holder into the space between the holder 2600 and the cover plate 2400 or the base plate 2300, into the space between the cover plate 2400 and the heater board 2100, and into the space between the orifice plate 2400a and the end portion 2100a of the heater board or the end portion 2300a of the base plate so that the wire connection portion is protected.

Next, the mounting of the ink jet head unit to the ink tank unit 1000 will be described. In Figs. 22 and 24, reference numerals 1610 and 2600f denote a projection and a tab having a spring property, which are attached to the ink tank unit case 1600 and the holder 2600, respectively, whereby the ink jet head unit can be prevented from falling by engagement of the two.

On the other hand, the connection opening portion 1101 of the ink jet head unit in the ink tank unit 1000 is connected to the ink tank connection portion 2600h of the ink head unit via an O-ring 1500 to prevent ink leakage.

The inkjet cartridge is completed in the manner described above.

Next, the packaging of the ink jet cartridge will be described. Fig. 27 shows the assembly of a protective tape 3100 and a protective cover 3200 for protecting the ejection ports from drying and solidifying or being damaged during distribution in the packaged state. The protective cover 3200 has a sponge 3220 in a portion contacting the ejection port side via the protective tape 3100, and the protective tape 3100 is urged into contact with the ejection port side by a pressing force of 500 to 2000 g from this sponge.

The protective cover 3200 has a projection 3210 which engages with the holder 2600, while the holder 2600 has a recess in which the projection is clamped on each side so that falling off is prevented by engagement of the two.

Fig. 28 shows the structure of a package 4000 for protecting the ink jet cartridge against environmental changes during distribution and for protection against falling. In Fig. 28, reference numeral 4100 designates a container body, reference numeral 4200 designates a container lid, and reference numeral 4300 designates a buffer body for protecting against vibration of the ink jet cartridge within the container.

The container body 4100 is formed of a mold made of polypropylene from the viewpoint of shock resistance, gas barrier ability for preventing evaporation of the ink from the inkjet cartridge, and cost. The container lid 4200 is made of a Multilayer film having excellent gas barrier property, for example, a multilayer film in which a polyethylene terephthalate layer of 12 µm, an aluminum vapor layer of 0.05 µm, a nylon layer of 15 µm, a polyethylene layer of 25 µm, an easily peelable layer of 25 µm are coated sequentially from the outermost layer or from the outside, or a multilayer film in which nylon of 15 µm, an aluminum foil of 9 µm and an easily peelable layer of 75 µm are coated sequentially from the outermost layer.

The packaging process is as follows.

After inserting the inkjet cartridge into the case body 4100, the buffer body 4300 is arranged therein, a welding rib 4120 arranged in a flange portion 4110 of the case body 4100 and the easy-peelable sheet of the case cover 4200 are welded to each other by heating to obtain a package.

Furthermore, this package 4000 is housed within an artistically printed cover 5100, and thus a package of the ink jet recording head is completed (see Fig. 29). In the above-explained example, a head cartridge having an ink tank unit and a head unit provided integrally was described, but the head unit and the ink tank unit may be provided separately as independent parts.

(Another embodiment)

Fig. 30 shows an embodiment of the ink jet recording apparatus in which a inkjet cartridge according to the present invention is mounted thereon.

In this drawing, reference numeral C denotes an ink jet cartridge of the present invention described above, and reference numeral 2 denotes a carriage for mounting for moving four ink jet cartridges corresponding to four color inks, i.e., yellow ink, magenta ink, cyan ink and black ink.

Here, the carriage 2 is slidably engaged with a guide shaft 11, with a part of the carriage 2 being connected to a belt 42 driven by a motor. Thus, the carriage 2 is movable along the guide shaft 11, allowing the ink jet cartridge C to be moved in the recording area and in the area adjacent thereto.

Reference numerals 15 and 16 denote feed rollers for driving the motor. By such a structure, a recording medium 10 is fed to a position facing the ejection port side of the recording head and fed to a paper discharge section via rollers 17 and 18 as recording continues.

In this embodiment, the recording medium 10 is conveyed along a conveying direction (sub-scanning direction) by the conveying rollers, and after the recording medium 10 is set at a predetermined recording position, the operation of recording (scanning) an image by the ink jet cartridge C mounted on the carriage 2 moving along the recording medium 10, feeding (pitch conveying) the sheet by a predetermined amount after recording one line and then recording (scanning) the image on the next line is repeated until the entire image is recorded on the recording medium.

Denoted by reference numeral 401 is a blade as a wiping member, one end of which is held by a blade holding member so that it becomes a secured end and the blade takes the form of a cantilever. The blade 401 is arranged at a position adjacent to the recording area having the recording head, and in this embodiment, it is held in the protruding form in the path of movement of the recording head.

Denoted by reference numeral 300 is a cap which is disposed at a home position adjacent to the sheet 401 and is movable forward and backward in the directions perpendicular to the moving direction of the recording head so as to make direct contact with the ejection port side, thereby effecting capping. Further, designated by reference numeral 403 is an absorbing member which is provided adjacent to the sheet 401 and is held in the path of movement of the recording head like the sheet 401 in the projecting form.

A discharge port recovery portion 500 is formed of the sheet 401, the cap 300, and the absorbing member 403, and the ink and dirt adhering to the ink discharge port side can be removed by the sheet 401 and the absorbing member 403.

By the above-described structure, when the ink jet cartridge C returns to the home position after completion of recording, the cover 300 of the ejection port recovery portion 500 of the recording head is retracted from the moving path of the ink jet cartridge C, but the blade 401 protrudes into the moving path. As a result, the ejection port side of the ink jet cartridge C is wiped by the protruding blade 401.

In addition, when the cap 300 is in direct contact with the ejection port side of the ink jet cartridge to effect capping, the cap 300 is moved so as to protrude into the path of movement of the cartridge. When the cartridge C is moved from the home position to the recording start position, the cap 300 and the blade 401 are at the same position as in the wiping described above. As a result, in the movement before starting recording, the ejection port side of the cartridge C is wiped.

Restoration of the ejection port portion of the recording head with the sheet is carried out at a predetermined distance not only during movement of the carriage before and after recording but also during recording.

It is to be noted that the ink adhering to this sheet 401 by the recovery can be absorbed by the ink absorbing member 104 (see Fig. 1A) on the side of the head, as previously described.

When the ink jet cartridge of the present invention is used for the above-described recording apparatus, the height H of the ink jet cartridge will not increase with the increased ink-receivable amount in the position where it is mounted on the carriage, since the ink-receivable amount of the ink tank unit is increased by increasing the Ink filling ratio has been increased in the present invention.

Therefore, it is possible to reduce the overall thickness since no porous member is arranged in the ink storage portion and to reduce the size of the cartridge when a plurality of ink jet cartridges are arranged side by side such as in a color recording apparatus as shown in Fig. 30.

In this embodiment, a recording head or a recording device of the ink jet recording system for carrying out the recording by forming flying liquid drops using the heat energy is applied among the various ink jet recording systems, but it may be applied to another suitable flying liquid drop structure.

The representative structure and principle of the ink jet system using thermal energy are disclosed, for example, in U.S. Patents 4,723,129 and 4,740,796, and preferably the present invention is put into practice using these basic principles. This recording system is applicable to both the so-called on-demand type and the continuous type.

In short, in this recording system, by applying at least one drive signal which causes a rapid temperature rise exceeding core boiling and causing a film boiling phenomenon in the ink, the drive signal corresponding to the recording information is applied to the electrothermal transducers arranged corresponding to the liquid channels holding a liquid (ink), Thermal energy is generated to cause film boiling on the heating surface of the recording head.

Thus, the on-demand type recording system is particularly effective because the bubbles within the liquid (ink) can be generated in a ratio of 1:1 to the drive signals applied to the electrothermal transducers. By ejecting the liquid (ink) through an ejection opening due to the growth and collapse of the bubble, at least one drop is generated. By shaping the drive signals into pulse shapes, the growth and collapse of the bubbles can be caused promptly and appropriately to achieve preferential ejection of the liquid (ink) which is excellent in response characteristic in particular.

For the drive signals having such a pulse shape, those drive signals disclosed in U.S. Patents 4,463,359 and 4,345,262 are suitable. Furthermore, excellent recording can be carried out by applying the conditions described in U.S. Patent 4,313,124, which relates to the temperature increase rate of the above-mentioned heating surface.

As for the structure of the recording head, in addition to the combination of the ejection port, the liquid passage and the electrothermal transducer (a straight liquid passage or a rectangular liquid passage) as disclosed in the above-mentioned respective specifications, the structure disclosed in U.S. Patents 4,558,333 and 4,459,600 in which such a structure is disclosed having a heating action portion disposed in the bent portion is also included in the present invention.

In addition, the present invention can also effectively employ the structure disclosed in Japanese Patent Application Laid-Open No. 59-123670, i.e., a structure using a slit common to a plurality of electrothermal transducers as a discharge port for the electrothermal transducer, or the structure of Japanese Patent Application Laid-Open No. 59-138461 having an opening for absorbing a pressure wave of heat energy corresponding to the discharge portion.

Furthermore, as for the recording mode of the recording apparatus, the present invention is particularly effective not only in the recording mode of only one main color such as black color and the like, but also in an apparatus equipped with at least a plurality of different colors or an apparatus for all colors by color mixing, wherein the recording head may be either integrally constructed or combined in a plurality.

In the ink jet head cartridge of the present invention, since the ambient air communication port of the negative pressure generating element accommodating portion of the ink tank and the ink supply port are arranged on the opposite surfaces with the ambient air communication port being arranged above the ink supply port, the state in which there is no ink in the vicinity of the ambient air communication port is easily maintained even when ink is accumulated in the vicinity of the ink supply port, and ink leakage is less likely to occur.

In addition, due to the effect of the negative pressure generating element as a buffer, in the state where the ink wetting occurs only in the vicinity of the ink supply port but not in the remaining portion, ink leakage is unlikely to occur since no ink is accommodated in the space portion.

Furthermore, in the cartridge of the present invention, by forming the ink storage portion into an L-shape or a U-shape, the volume of the ink storage portion can be made larger than that of the negative pressure generating element accommodating portion, whereby the reduction in running cost can be realized without an increase in the size of the ink tank.

Furthermore, in the cartridge of the present invention, by rounding the angled edge portion within the negative pressure generating element receiving portion with R1 to R3 to form four curved corners, the peeling or deformation at the angled portion of the negative pressure generating element when inserting the negative pressure generating element can be suppressed, resulting in no gap between the ink storage portion and the negative pressure generating element, thereby concentrating the ink in the vicinity of the ink supply port without the ink flowing in the vicinity of the ambient air communication port being arranged upward, whereby leakage of ink can be prevented beforehand.

By providing a groove portion having a height of the upper portion of less than 5 mm from the filter surface at the end portion of the ink connecting member of the ink jet head unit at The partition wall inside the inkjet ink cartridge enables the ink supply to the recording head to be carried out stably and extremely reliably.

In addition, by providing a recessed portion at the bottom portion of the negative pressure generating element accommodating portion (the ink absorbing element accommodating portion) of the ink cartridge for the ink jet, the ink flow path can be secured wider, resulting in no interruption in the ink supply.

Furthermore, according to the present invention, by dividing one opening of the ambient air communication port into two or more openings, the necessity of providing the plurality of parts or the unevenness in molding as occurred conventionally can be improved and the structure of the ambient air communication port can be achieved with high productivity and reliability, which can be applied to the ink storage container using the negative pressure generating member of either the division type or the integral type.

By a recording head having an ink container portion having first and second accommodating chambers and an ink ejecting portion, there is an effect that both a more stable gas-liquid interface in supplying the ink within the ink chamber in the ink container portion to the negative pressure generating element and a more stable supply of ink can be achieved.

In addition, by designing the vertical edge lines of the first accommodation chamber and the second By forming the first accommodation chamber in a curved shape and providing a projection on the bottom surface of the second accommodation chamber in the vicinity of the very small communication portion, there is an effect that the leakage of ink through the ambient air communication port due to the change in posture during distribution or due to changes in ambient temperature or ambient humidity can be prevented.

As described above, by the present invention, an ink jet head cartridge having a large ink storage capacity with high reliability in preventing ink leakage and ink leakage can be provided, and an ink jet recording apparatus capable of excellent printing for a long period of time can be provided.

Claims (13)

1. An ink tank unit (200; 1000) mountable to an ink jet recording apparatus so as to assume a relative position in use device with respect to the ink jet recording apparatus and storing ink to be supplied to an ink jet head (100; 2000) for ejecting the ink, the ink tank unit comprising: a partition (215; 1100a) for dividing the ink container unit (200; 1000) into a first chamber (203; 1100) and a second chamber (204; 1200, 1250), wherein the first chamber (203; 1100) houses a negative pressure generating element (205; 1102) and has an ink supply port (209; 1101) for supplying the ink to the inkjet head (100; 2000) and an ambient air connection section (208; 1150) which communicates with the ambient air, and wherein the second chamber (204; 1200, 1250) communicates with the first chamber (203; 1100) via an ink connection section (206; 1300) and houses the ink to be supplied to the first chamber (203; 1100), characterized in that the second chamber (204; 1200, 1250) is substantially sealed except for the ink connection portion (206; 1300); and the first chamber (203; 1100) has edge line sections (210; 1115a, 1115b, 1115c, 1115d) which are rounded so that the negative pressure generating element (205; 1102) is pressed substantially uniformly at its edges, and which extend in the insertion direction of the negative pressure generating element. 2. The ink container unit according to claim 1, wherein the rounded edge line portions (310; 1115a, 1115b, 1115c, 1115d) are vertical with respect to the ink jet recording apparatus in the predetermined use relative position. 3. The ink tank unit according to claim 1 or 2, wherein, at the predetermined relative use position with respect to the ink jet apparatus, the ink connecting portion (206; 1300) is provided at a position where the ink supply direction from the second chamber (204; 1200, 1250) to the first chamber (203; 1100) is perpendicular to a main scanning direction in which the ink tank unit (200; 1000) is moved during the printing operation of the ink jet apparatus. 4. The ink container unit according to claim 1, 2 or 3, wherein the first chamber (203; 1100) has a recessed portion (217; 1120) between the ink supply port (209; 1101) and the ink communication portion (206; 1300). 5. The ink tank unit according to claim 1, 2 or 3, wherein the partition (215; 1100h) has a groove portion (216) leading to the ink communication portion (206; 1300) on the side of the first chamber (203; 1100). 6. The ink tank unit according to claim 1, 2 or 3, wherein the ambient air communication portion (208; 1150) has an ambient air communication opening (208, 218; 1152) at a position opposite to the ink supply opening (209; 1101). 7. The ink tank unit according to claim 1, 2 or 3, wherein the first chamber (203) has at least two or more negative pressure generating elements (205-1, 205-2; 205-3, 205-4). 8. Ink container unit according to claim 1 or 2, wherein the ambient air communication portion (208; 1150) is spaced from the negative pressure generating element (205; 1102). 9. Inkjet cartridge with an inkjet head unit (100; 2000) connected to an ink container unit (200; 1000) according to one of the preceding claims. 10. An inkjet cartridge according to claim 9, wherein the inkjet head unit (100; 2000) has electrothermal transducers that effect ejection in such a manner that a state change in the ink is caused by generating heat with electric energy supplied for ejecting the ink. 11. An ink jet cartridge according to claim 9 or 10, insofar as these claims are dependent on claim 5, wherein the ink jet head unit (100; 2000) has an ink connector (105) inserted into the ink supply port (209; 1101), the distance from an end portion of the ink connector (105) to an upper end of the groove portion (216) being less than or equal to 5 mm. 12. Inkjet device with: an inkjet cartridge (C) according to one of claims 9 to 11; a carriage (2) on which the inkjet cartridge (C) is removably mounted; and Conveying means for conveying a recording medium (10) which receives the ink ejected from the ink jet head unit (100; 2000). 13. The ink jet apparatus according to claim 12, wherein, at the predetermined relative use position of the ink tank unit (200; 1000), the ink connecting portion (206; 1300) is provided at a position where the ink supply direction from the second chamber (204; 1200, 1250) to the first chamber (203; 1100) is perpendicular to a main scanning direction in which the ink tank unit (200; 1000) is moved during the printing operation of the ink jet apparatus.