HK1065285B - A replaceable cartridge - Google Patents

Description

Replaceable ink cartridge

This application is a divisional application filed on the filing date of 24/7/1993 under the filing number 01125545.5 entitled "liquid container for liquid ejecting head".

Technical Field

The present invention relates to replaceable ink cartridges for ink jet printers.

Background

An ink tank used with an ink jet recording apparatus is to supply an amount of ink appropriately in accordance with an amount of ink ejected by a recording head during recording, while preventing the ink from leaking through an ejection port of the recording head when recording is not performed.

When the ink tank is of a replaceable type, it is required that the ink tank and the recording apparatus can be easily attached and detached without leaking the ink, and that the ink is surely supplied to the recording head.

A common example of an ink tank usable with an ink jet recording apparatus is disclosed in japanese laid-open patent application No.87242/1988 (first prior art), in which an ink jet recording ink cartridge is provided with an ink tank having a foam material and a plurality of ink ejection holes. Such as a foamed polyurethane material, and therefore can create a negative pressure by virtue of capillary forces in the foam material, preventing ink from leaking from the ink tank.

Japanese laid-open patent No.522/1990 (second prior art) discloses an ink jet recording ink cartridge in which a first ink tank and a second ink tank are connected together with a porous material, and the second ink tank is connected to an ink jet recording head with a porous material. In this prior art, the porous material is not contained in the ink tank, but is provided only in the ink passage, which improves the ink utilization. Since the second ink storage portion is provided, the air expands due to the temperature rise (pressure drop) in the first ink tank, and the ink flowing out therefrom is stored, so that the degree of vacuum of the recording head during recording is maintained substantially constant.

However, in the first prior art, the foam is required to occupy substantially the entire space in the ink tank, and thus, the ink capacity is limited. In addition, the amount of unused ink left is relatively large, i.e., the ink utilization rate is low. This is a problem with the prior art. In addition, it is difficult to measure the amount of ink remaining and to maintain a substantially constant vacuum as the ink is consumed. These are additional problems.

In the second prior art, when no recording is made, since a material for generating a vacuum is disposed on the ink passage. Therefore, a sufficient amount of ink is present in the porous material, but the negative pressure generated by the capillary force of the porous material is not sufficient, and as a result, only a slight impact or the like needs to occur, and the ink leaks through the small hole in the ink jet recording head. This is a problem. If the ink cartridge is replaceable, its ink jet recording head is integrated with an ink tank mounted on the ink jet recording head, which makes it impossible to use the second prior art. This is yet another problem.

Japanese patent nos. 67269/1981 and 988571984 disclose an ink tank using a spring-pressurized oil bag, which has an advantage in that the internal negative pressure generated in the ink supply portion is stabilized by the spring force. However, this device has problems in that the limited spring profile, the required internal negative pressure, and the method of fixing the ink tank to the ink bag are complicated and therefore expensive. In addition, for thin ink tanks, the ink retention is small.

Japanese patent No 214666/1990 discloses a divided chamber type ink tank, the internal space of which is divided into a plurality of ink chambers, each chamber being communicated with each other by a small hole for providing negative pressure. In the divided chamber type ink tank, the internal negative pressure of the ink supply portion is generated by the capillary force of the small orifice communicating with the ink chamber. In this device, the ink tank is simpler in structure than the elastic bag device, and therefore, is advantageous in terms of manufacturing cost. Besides, the shape of the ink tank is not limited by the structure. However, the divided chamber type has a problem that when the position of the ink tank is changed, the small hole does not receive the ink according to the amount of the ink left, and as a result, the internal negative pressure is unstable and may even leak the ink, and thus the use of the ink tank is limited.

Disclosure of Invention

Accordingly, it is a primary object of the present invention to provide a tank which is easy to handle, an ink jet recording head using such an ink tank, and an ink jet recording apparatus using such an ink tank.

It is another object of the present invention to provide an ink tank which can make the ink retention rate high, an ink jet recording head using such an ink tank, and an ink jet recording apparatus using such an ink tank.

It is still another object of the present invention to provide an ink tank in which ink does not leak out of the ink tank even if the working environmental conditions are changed, an ink jet recording head using such an ink tank, and an ink jet recording apparatus using such an ink tank.

It is still another object of the present invention to provide an ink tank which supplies ink in a stable degree of vacuum without being affected by changes in environmental conditions so that the supplied ink can enter a recording head without affecting the ejection performance of the ink, an ink jet recording head using such an ink tank, and an ink jet recording apparatus using such an ink tank.

It is still another object of the present invention to provide an ink tank, an ink, a recording head and an ink jet recording apparatus which make efficient use of the ink by using a vacuum generating device.

It is still another object of the present invention to provide an ink tank, an ink jet recording head which receives mechanical impact such as vibration, or a drastic change in temperature, or which reliably prevents ink from leaking even when the ink tank is in use or when the ink jet recording apparatus is transported.

The present invention provides a replaceable ink cartridge for an ink jet printer having a mounting for receiving the replaceable ink cartridge and supporting the ink cartridge during ink jet printing, the replaceable ink cartridge comprising: a can formed from front, back, top, bottom and side walls; the canister is internally divided into a first chamber and a second chamber; said first chamber and said second chamber having a common dividing wall extending vertically downwardly toward said bottom wall to provide an opening formed by said dividing wall between said first chamber and said second chamber proximate said bottom wall; the first cavity is substantially sealed from ambient air except through the opening; said second chamber having a vent for allowing ambient air to enter said second chamber; the first chamber contains a liquid ink reservoir; said second chamber having an ink supply outlet; the second cavity contains a spongy material for holding ink; at least one slot in the second chamber side of the dividing wall extending from the opening and terminating at a point partially above the dividing wall to form an air flow path from the second chamber to the first chamber; said sponge-like material being located within said second chamber to allow air flow from said vent to said gutter to allow air to be introduced into said first chamber when the level of ink held within said sponge-like material is close to said point where said gutter portion terminates partially above said dividing wall, liquid ink flowing through said opening into said ink supply outlet; and the canister is removably mountable in an inkjet printer mount with the bottom wall down.

Drawings

The above and other objects, features and advantages of the present invention will be more apparent upon consideration of the following description of preferred embodiments of the present invention, taken in conjunction with the accompanying drawings.

Fig. 1 is a connection between a recording head and an ink tank according to an embodiment of the present invention.

FIG. 2 shows a recording head and an ink tank according to another embodiment of the present invention.

Fig. 3 is an ink tank according to an embodiment of the present invention.

Fig. 4 is a perspective view of the recording apparatus.

FIG. 5 is an ink tank according to yet another embodiment of the present invention.

FIG. 6 is an ink tank according to another embodiment of the present invention.

FIG. 7 is an ink tank according to yet another embodiment of the present invention.

FIG. 8 is an ink tank according to yet another embodiment of the present invention.

FIG. 9 is an ink tank according to yet another embodiment of the present invention.

Fig. 10 shows an ink supply method.

FIG. 11 is a graph showing the change in internal pressure in the ink supply portion in the ink tank according to the embodiment of the present invention.

Fig. 12 shows an ink supply method in a comparative example.

Fig. 13 is a graph showing a change in pressure in the ink supply portion in the comparative example.

Fig. 14 is an original state when the ink tank is full of ink.

FIG. 15 shows a state where a gas-liquid interface starts to be formed.

Fig. 16 shows a state in which the ink is almost exhausted.

Fig. 17 shows a state when the ink is used up.

Fig. 18 is a perspective view of a recording head apparatus having 4 units incorporated therein, and a corresponding ink tank used for the apparatus.

FIG. 19 is an ink tank according to yet another embodiment of the present invention.

Fig. 20 shows an ink supply method.

FIG. 21 is a longitudinal sectional view of an ink cartridge main body for ink-jet recording according to still another embodiment of the present invention.

Fig. 22 is a cross-sectional view of the ink cartridge main body in the ink jet recording apparatus of fig. 21.

FIG. 23 is a cross-sectional view of the ink cartridge body, particularly illustrating the surface of the rib of FIG. 21.

FIG. 24 is a sectional view of the ink cartridge body, showing the surface of a rib according to another embodiment of the present invention.

FIG. 25 is an enlarged cross-sectional view of a rib in accordance with another embodiment of the present invention.

FIG. 26 is a longitudinal sectional view of a cartridge body of a replaceable ink jet recording apparatus according to still another embodiment of the present invention.

FIG. 27 is a cross-sectional view of an ink cartridge main body of an exchangeable ink-jet recording apparatus according to still another embodiment of the present invention.

FIG. 28 is a cross-sectional view of a main body of an ink cartridge according to still another embodiment of the present invention, showing the surface of a rib.

FIG. 29 is a longitudinal sectional view of an ink cartridge main body for an ink jet recording apparatus according to a comparative example.

Fig. 30 is a sectional view of the ink cartridge main body for the ink jet recording apparatus in this comparative example.

FIG. 31 is a cross-sectional view of an ink cartridge body showing the surface of a rib in a comparative example.

Fig. 32 is an enlarged sectional view showing a cross section of the rib plate in this comparative example.

Fig. 33 is a horizontal printing position.

FIG. 34 is a buffer effect of ink penetration by the compressed ink absorbing material in the ink chamber.

FIG. 35 is an example of a compression ratio profile in an ink absorbing material compressed according to yet another embodiment of the present invention.

Fig. 36 is another example of a compression ratio distribution of the ink absorbent material compressed in the embodiment of fig. 35.

FIG. 37 is still another example of a compression ratio distribution of the ink absorbing material compressed in the embodiment of FIG. 35.

Fig. 38 is an example of a compression ratio distribution of the ink absorbing material compressed in the comparative example.

Fig. 39 is still another example of the compression ratio distribution of the ink absorbing material compressed in the comparative example.

FIG. 40 is an example of an additional ink chamber according to yet another embodiment of the present invention.

FIG. 41 is an example of an additional ink chamber in the embodiment of FIG. 40.

FIG. 42 is an example of a separate compressed ink absorbing material in accordance with yet another embodiment of the present invention.

FIG. 43 is an example of the placement of an ink absorbing material in an ink chamber in accordance with yet another embodiment of the present invention.

Fig. 44 is a problem in assembling the device of the embodiment of fig. 43.

FIG. 45 shows ink consumption in comparative examples.

FIG. 46 shows ink leakage when the pressure is reduced in the comparative example of FIG. 45.

Fig. 47 is a modified example of the further embodiment of the present invention.

Fig. 48 is a modified example of the embodiment of fig. 47.

FIG. 49 is a cross-sectional view of an embodiment of the present invention showing a replaceable ink tank and a recording head mounted on an ink cartridge.

FIG. 50 is the consumption of ink in the apparatus of the embodiment of FIG. 49.

Fig. 51 is a principle of exchange between air and ink.

Fig. 52 shows the internal pressure of the ink supply portion according to the further embodiment of the present invention.

FIG. 53 is an ink cushioning effect in the device of the embodiment of FIG. 52.

Fig. 54 is an example of a block diagram of a control system for the apparatus.

FIG. 55 shows a state where the remaining amount of ink is detected according to still another embodiment of the present invention.

FIG. 56 is an internal pressure of an ink supply portion of the ink tank of the embodiment of FIG. 55.

Fig. 57 shows an example of the ink replenishment method.

FIG. 58 shows ink consumption according to yet another embodiment of the present invention.

FIG. 59 is a further ink consumption of the embodiment of FIG. 58.

FIG. 60 is a graph showing the detection of the remaining amount of ink in the apparatus of the embodiment of FIG. 58.

Fig. 61 shows a state where the ink is injected again after the ink in the ink chamber is used up.

FIG. 62 is a diagram illustrating the detection of the remaining amount of ink according to still another embodiment of the present invention.

FIG. 63 is a modified residual ink volume detection of the embodiment of FIG. 62.

FIG. 64 is a method of replenishing ink in accordance with yet another embodiment of the present invention.

FIG. 65 shows the ink flow rate when the pressure is decreased.

Fig. 66 shows the relationship between the remaining ink amount and the inter-electrode resistance.

Detailed Description

Fig. 1 is a sectional view of a recording head, an ink tank and a carriage in an ink jet recording apparatus according to an embodiment of the present invention. In this embodiment, the recording head 20 is of an ink jet type, which generates heat energy by an electrothermal transducer according to an electric signal to cause thin layer boiling in the ink. In fig. 1, the recording head 20 is mainly attached to or laminated with the recording head base plate 111 by positioning reference projections 111-1 and 111-2 provided on the recording head base plate 111 in a stacked configuration. The positioning is effected by the head positioning portion 104 and a projection 111-2 on the carriage HC in the direction perpendicular to the drawing sheet of fig. 1. In the vertical direction of the cross section of fig. 1, a part of the projection 111-2 projects to cover the positioning portion 104 of the recording head, but a cut-away (not shown) portion of the projection 11-2 and the recording head positioning portion 104 are used for correct positioning. The heating plate 113 is made by a film forming process, and includes a sheet heat exchanger (a jet heater) disposed on a Si substrate and an electric power line for supplying power thereto, and the electric power line may be made of metal such as aluminum. The circuit is made to conform to a flexible board (PCB of the recording head) of the recording head accommodating the circuit, and the end of the flexible board has a pad for receiving an electric signal transmitted from a host computer. These elements are connected by wires. Integral top plate 112, made of polysulfone or the like, has a wall plate of a valve block for separating a plurality of ink channels corresponding to the jet heaters. A common fluid chamber is provided for receiving ink from the replaceable ink cartridge through a single passage, and ink is supplied to the ink supply ports through a plurality of ink passages, and a plurality of orifices are provided for use as ejection ports. The top plate 112 is pressed against the heating plate 113 by a spring, not shown, and the heating plate is pressed and spaced by a sealing member, so that an ink ejection outlet portion is formed.

To communicate with the replaceable ink cartridge 1, a passage 115, which is sealingly combined in the top plate 112, passes through a number of holes of the recording head PCB113 and the recording head base plate 111 to the opposite side of the recording head base plate 111. In addition, the recording head PCB113 is connected and fixed on the recording head substrate 111 at the penetrating portion. A filter 25 is provided at one end of the passage 115 connected to the ink cartridge 1 to prevent foreign substances or air bubbles from entering the ink ejecting section.

The replaceable ink cartridge is connected to the recording head 20 by a restraint rail and pressing means 103, and the ink absorbing material in the ink supply portion is brought into contact with the filter 25 at one end of the passage 115, so that mechanical connection can be accomplished. After this connection, the ink is supplied in such a manner that the ink is forcibly fed from the replaceable ink cartridge 1 to the recording head 20 by the recording head suction recovery pump 5015 in the recording apparatus main body.

In this embodiment, the recording head 20 and the replaceable ink cartridge 1 are connected to each other by the pressurizing means, and at the same time, the recording head 20 and the holder HC are mechanically and electrically connected in the same direction, so that the positioning between the pad on the recording head PCB105 and the driving electrode 102 of the recording head is reliably achieved.

In this embodiment, the seal is a relatively thick ring of elastic material so that the portion of the connection with the outer wall of the replaceable ink container has sufficient width to seal the ink supply portion.

As described above, in the present embodiment, the replaceable ink cartridge 1 and the recording head are completely combined, so that the carriage and the recording head can be reliably positioned with respect to each other with a simple structure by pressing the replaceable ink cartridge, and at the same time, the recording head and the replaceable ink cartridge are connected with a simple structure outside the main body, so that they can be mounted on the carriage. Therefore, the replacement operation is simple and convenient. In this embodiment, the electrical connection between the carriage (host device of the recording apparatus) and the recording head is achieved simultaneously. Therefore, the operability of the replacement recording head and the replaceable ink cartridge is excellent. One possible alternative is to use a separate junction box to complete the electrical connection, but this increases the width of the arrangement to ensure positioning of the recording head and connection to the replaceable cartridge. Fig. 4 shows a horizontal type recording apparatus. The arrangement and operation of the recording head in the ink jet recording apparatus of the present embodiment will be described with reference to fig. 4. In fig. 4, the recording paper P is fed upward by a flat roller 5000, and is pressed against the flat roller 5000 by a paper pressing plate 5002 throughout the entire range of the carriage movement direction. A carriage moving pin of the carriage HC is engaged in the spiral groove 5004. The carriage is supported by a lead screw 5005 (drive member) and a lever 5003 parallel to the lead screw, and is reciprocatingly movable along the surface of the recording paper P on the flat roller 5000. The lead screw 5005 is driven to rotate by a driving roller which can rotate in the normal and reverse directions via the moving gears 5011 and 5009, and reference numerals 5007 and 5008 denote photosensitive couplings for detecting whether or not the carriage lever 5006 is right in front to switch the rotational direction of the motor 5013 (end position sensors). The signal for recording an image is transmitted to the recording head in a time relationship with the movement of the carriage with the recording head, and the dots are ejected to appropriate positions, thereby completing the recording operation. Reference numeral 5016 denotes a member for bearing on the cap member 5002 for capping the front surface of the recording head. Reference numeral 5015 denotes a suction device for sucking inside the cover. So that it relies on suction through the orifice 5023 in the cap to effect refreshing or rejuvenation of the recording head. The cleaning bracket 5017 is supported by a support 5019 for reciprocating the bracket, and both of these components are supported on a support plate 5018 of the main body. The suction device, bracket or similar may also be of other known types. The lever 5012 for determining the timing of the suction and recovery actions moves together with the cam 5020 in contact with the carriage. The driving force transmitted from the driving motor is controlled by a known transmission such as a clutch. When the carriage enters the end position or a region close to the end position, the restoring device performs a predetermined operation process for a predetermined time period at the corresponding position by the lead screw 5005.

As shown in fig. 33, the inkjet recording apparatus of this embodiment is operated in the vertical printing position. In the vertical position, the recording scanning process is performed with the recording material P facing the bottom surface of the recording head 2010. At this time, the feeding, the positioning, and the discharging of the sheet can be performed on substantially the same plane, and therefore, it is possible to perform the positioning on a thick and rigid recording material such as a postcard and an OHP sheet. The housing of the ink jet recording apparatus of this embodiment, which is determined to be replaceable, is provided with 4 rubber pads on the bottom surface of fig. 4, and two ribs and a retractable auxiliary leg 5018 on the right side surface. Therefore, the printing searching device can be stably placed at the corresponding searching position. In the vertical seek position, the replaceable ink cartridge 2001 is above the ink ejection portion of the recording head 2010 facing the recording material P, and therefore, it is necessary to support the hydrostatic head generated by the ink while maintaining a small positive pressure, and preferably a small internal negative pressure, in the ink ejection portion, so that the meniscus of the ink in the ink ejection portion can be kept stable.

The recording apparatus shown in fig. 4 and 33 may be used in various embodiments of the present invention to be described below.

For the ink cartridge of the present invention, a detailed description will be made, and first, the structure and operation of the ink cartridge will be described.

(Structure)

As shown in fig. 2, the ink cartridge has an opening 2 in its body for communicating with the ink jet head, a material chamber (or tank) 4 for receiving a vacuum-producing material 3, and an ink-holding chamber or tank 6 for holding ink, the ink tank 6 being adjacent to the vacuum-producing material tank, separated by ribs 5, and communicating with the vacuum-producing material tank 4 at the bottom 11 of the ink cartridge.

Working process (1)

Fig. 2 is a schematic sectional view of an ink cartridge in which a connector 7 for supplying ink to an ink jet recording head is inserted into the ink cartridge and projects into a material for generating a vacuum, so that the ink jet recording apparatus is in an operating state. A filter may be provided at an end of the connector to remove foreign materials from the ink cartridge.

When the ink jet recording apparatus is operated, ink is ejected through one or more orifices of the ink jet recording head, and thus, an ink suction force is generated in the ink tank. Ink 9 is sucked into the material tank 4 which is drawn from the ink tank 6 into the connecting member 7 through the gap 8 between the end of the rib and the ink cartridge bottom plate 11 and vacuumed by the material 3 which generates a vacuum, and then the ink is supplied to the ink jet recording head. Thereafter, the internal pressure of the ink tank 6, which is sealed except for the void 8, drops, and as a result, there is a pressure difference between the ink tank 6 and the material tank 4 where vacuum is generated. As the recording operation continues, the pressure difference increases. Since the vacuum-producing material tank 4 is vented to the atmosphere through a vent hole, air enters the ink tank 6 through the vacuum-producing material and the space 8 between the rib end 5 and the ink cartridge bottom plate 11. At this time, the pressure difference between the ink tank 6 and the material tank 4 where the vacuum is generated disappears. The above process is repeated throughout the ink jet recording process, so that a substantially constant vacuum is maintained in the ink cartridge. The ink in the ink tank can be used substantially entirely except for the ink adhered to the inner wall surface of the ink tank, and therefore, the utilization of the ink is improved.

Working process (2)

The main operation of the ink tank is described in further detail according to the model shown in fig. 10.

In fig. 10, the ink tank 106 corresponds to the ink tank 6 in fig. 2, and contains ink therein. Reference numerals 102, 103-1 and 103-2 refer to capillaries corresponding to the vacuum-generating material 3. A vacuum is created in the ink tank by the surface tension of the capillary tube. The element 107 corresponds to the connecting member 7, which is connected to an ink jet recording head, not shown, for supplying ink from an ink tank. The ink is ejected through the orifice and flows in the direction indicated by arrow Q.

The state shown in this figure is a state in which a small amount of ink is already discharged from the material that generates vacuum, and therefore, a small amount of oil is also discharged from the ink tank in a state in which the ink tank and the material that generates vacuum are filled with ink. Pressure equilibrium is established between the hydrostatic head at the orifice of the recording head, the pressure drop in the ink tank 106, and the surface tension in the capillaries 102, 103-1, and 103-2. When ink is output from this state, the ink level in the capillaries 103-1 and 103-2 hardly changes, and ink is output from the ink tank 106 through the space 108 corresponding to the space 8. Thus, the degree of vacuum in the ink tank 106 can be increased. The meniscus of capillary 102 is then changed, creating one or more bubbles. The bubble enters the ink reservoir 106 due to the meniscus break. The amount of ink consumed is replenished from ink tank 106 in this manner without significant changes in the liquid level in capillaries 103-1 and 103-2, i.e., without significant changes in the distribution of ink in the vacuum-producing material, i.e., maintaining an equilibrium internal pressure.

When a total amount of ink Q is supplied, this change in volume is represented by a change in meniscus height in the capillary 102, and this change in meniscus surface energy increases the negative pressure of the ink supply portion. However, the destruction of the meniscus allows air to enter the ink reservoir, with the result that air replaces the ink and the meniscus returns to its original position. Thus, the internal pressure of the ink supply portion is maintained at a predetermined internal pressure by the capillary force of the capillary 102.

Fig. 11 shows the internal pressure in the ink supply portion of the ink tank according to this embodiment of the invention, as a function of the total amount of ink supply (consumption amount). As described above, in the starting state (fig. 14), ink supply is started from the material tank where vacuum is generated. More specifically, the ink contained in the vacuum-producing material tank is supplied until a meniscus is formed at the void 8 at the bottom of the ink tank. Thus, as with prior art ink tanks filled with ink-receptive materials, the internal pressure in the ink supply is created by the balance between the surface tension of the ink on the top surface (air-liquid interface) of the compressed chew material in the vacuum-generating material tank and the hydrostatic head of the ink itself. As described above, since the ink in the material tank in which the vacuum is generated decreases with the consumption (supply) of the ink to a state where a gas-liquid interface is formed at the bottom of the ink tank (point X in fig. 15 and 11), the supply of the ink from the ink tank is started. The internal pressure of the ink supply portion is maintained by the capillary force of the compressed ink absorbing material adjacent the bottom of the ink chamber. The internal pressure remains substantially constant as long as ink is supplied from the ink tank. When the ink is further consumed, causing the ink level in the ink tank to drop below the bottom of the ink chamber wall, the ink in the ink tank is substantially consumed (point Y in fig. 16 and 11). Since the ink tank is open to the outside atmosphere, air can immediately enter the ink tank. Thus, a small amount of ink remaining in the ink tank is absorbed by the compressed ink-absorbing material contained in the vacuum-generating material tank, so that the amount of ink contained in the vacuum-generating material tank is increased. This causes the internal pressure of the ink supply portion to change in a positive direction by a slight rise in the top surface (gas-liquid interface) of the ink. When the ink is further consumed, the ink in the canister that creates the vacuum is consumed. However, if the ink supply portion is lowered at the air-liquid interface, the recording head starts sucking air, and the ink supply device reaches the limit (fig. 17). When this state is reached, the ink tank needs to be replaced. After research and study, the inventors found that stable internal pressure of ink can be maintained from the beginning by performing suction recovery operation at the connection with the recording head by using a suction device of the main unit of the recording apparatus to remove air bubbles generated in the ink channel during the communication operation and to cause a small amount of ink to flow out of the ink tank. Further, even if the ink is supplied from the material tank in which the vacuum is generated to the outside in the initial stage and the stage immediately before the ink cartridge is replaced, the recording performance is not adversely affected as long as the ink is stably supplied as shown in fig. 11, and the recording operation can be smoothly performed. In order to establish the ink supply manner according to the above mechanism, the following points are noted:

a stable meniscus between the ink and the atmosphere needs to be formed closest to the gap 8. Otherwise, in order to move the meniscus into the ink tank, the ink must be consumed to such an extent that a high degree of vacuum is generated in the ink supply portion. In that way, the recording apparatus is difficult to operate at a high frequency, and therefore, is disadvantageous from the viewpoint of improving the recording operation speed.

Fig. 11 shows the change in internal pressure in the ink supply portion of the ink tank with the amount of ink supplied (consumption amount). The figure shows a so-called static pressure P111 in the non-ink-supplying state and a so-called dynamic pressure P112 in the ink-supplying state.

The pressure difference between the dynamic pressure P112 and the static pressure P111 is the pressure loss δ P at the time of ink supply. The negative pressure generated when the meniscus is moving is significant.

Therefore, the meniscus must be broken at this location without delay. For this purpose, an air introduction passage is provided to forcibly introduce air to the vicinity of the gap 8. Several embodiments of this aspect will be described below.

Example 1

Fig. 3 shows a first embodiment. The material 3 for creating a vacuum in the ink tank is an ink absorbing material, such as a material like polyurethane foam. When the absorbent material is placed in the vacuum-generating material tank 4, a space a32 is left in a portion of the vacuum-generating material tank, so that it functions as a passage for introducing air. This gap extends to the vicinity of the gap 8 between the bottom of the ink container 11 and the end 8 of the rib 5. Thus, it is vented to atmosphere through the vent. When the ink supply from the ink supply portion is started, the ink in the absorbent material 3 is consumed first, and the internal pressure of the ink supply portion reaches a predetermined value. The ink surface a31 shown in fig. 3 is then stably formed in the absorbent material 3, while a meniscus between the ink and the atmosphere is formed adjacent the gap 8. The height of the gap 8 is preferably not more than 1.5mm and is as long as possible in its length direction. After this condition is established, the meniscus at the gap 8 is not disrupted by continued ink consumption without delay. Thus, the ink can be stably supplied without increasing the pressure loss δ p. Therefore, stable ink ejection can be obtained at high speed printing.

When the recording operation is not performed, the surface tension of the material itself that generates the vacuum (or the surface tension at the interface between the ink and the material that generates the vacuum) is kept constant, and therefore, the ink can be prevented from leaking from the ink jet recording head.

To utilize the ink tanks of the present invention in a color ink jet recording apparatus, separate ink cartridges may be loaded with different colors of ink (e.g., yellow, black, magenta, and blue-green). The individual ink cartridges may be combined into an ink cartridge group. Another way of providing an ink cartridge group is to provide a replaceable ink cartridge for the most common black ink, and a replaceable ink cartridge in combination with several color ink tanks. Other combinations may be used depending on the requirements of the ink set being used.

The present invention is described in more detail below.

In the case of using the ink tank of the present invention, in order to control the degree of vacuum in the ink jet recording head, it is preferable to select the following parameters: material, shape and dimensions of the material 3 creating the vacuum; the profile and dimensions of the rib end 8; the shape and size of the space 8 between the rib end 8 and the ink tank bottom 11; the volume ratio between the material tank 4 and the ink tank 6 that creates the vacuum; the shape and dimensions of the connecting piece 7, and its depth of insertion into the ink tank; the shape, size and number of filters; and also the surface tension of the ink.

The member material for generating a vacuum may be any known material as long as it can withstand the weight of the liquid (ink) stored therein and small vibrations. Such as a sponge-like material made of fibers and a porous material having continuous micro-pores. Cellular plastics, preferably made of polyurethane foam, are preferred because of their ease of vacuum regulation and ability to retain stored ink. In particular, with such a foam, the density of its cells can be adjusted during the manufacturing process. When the foam is subjected to a thermal compression treatment to adjust its cell density, it is decomposed by heat, with the result that the properties of the ink are changed, and adverse effects on the recording quality may be caused, and therefore, cleaning is also required. In order to meet the requirements of various ink cartridges for various ink jet recording apparatuses, foam materials having a corresponding cell density are required. Rather than using thermal compression to manipulate the foam, it is preferred to cut a predetermined number of cells (number of pores per inch) into the desired size and then place the cut foam in a vacuum-producing tank to provide the desired cell density and capillary force.

A change in environmental conditions in the inkjet recording apparatus.

In an ink cartridge having a closed ink tank, ink may leak out. This is because, when the environmental conditions of the ink tank installed in the ink jet recording apparatus change (temperature rise or pressure rise), air in the ink tank expands (ink also expands), pressing the ink contained in the ink tank outward, and as a result, the ink leaks out. In the ink cartridge of this embodiment, the volume of air expansion in the closed ink tank (including the volume of ink expansion, although this amount is small) is considered in light of the expected worst environmental conditions, and a corresponding amount of ink is dispensed from the ink tank into the vacuum-producing material tank. The position of the vent is not limited, except that it is higher than the opening for connection to the canister of vacuum-producing material. In order to allow the ink to flow to the vacuum-producing material at a location remote from the connection opening even when the environmental conditions change, the vent opening is preferably located at a location remote from the connection opening. The number, shape, size, etc. of the vents can be determined by one of ordinary skill in the art based on the evaporation of the ink.

Transportation of the ink cartridge itself.

The connection opening and/or the vent are preferably sealed with a seal or sealing material during transportation of the cartridge itself to prevent evaporation of the ink or expansion of the ink and air within the cartridge. The seal is preferably a single-layer separator used in the packaging industry, a multi-layer seal made of a single-layer separator and a plastic film or a composite separator material, among which is a single-layer separator, a plastic film and an aluminum foil or a reinforcing material such as paper and cloth. It is preferable to further apply an adhesive layer of the same or similar material as that of the cartridge main body and thermally adhere it to improve the air-tight sealing property.

In order to prevent air from entering and ink from evaporating, it is effective to package the ink cartridge. The air is then drawn from the inside and sealed. As for the packing material, it is preferable to select from the above-mentioned separator materials in view of air permeability and liquid permeability.

By properly selecting the ink cartridge as described above, the leakage of ink can be prevented with high reliability during the transportation of the ink cartridge.

A method for manufacturing the same.

The material of the cartridge main body may be any known material. However, it is desirable that such a material does not affect the ink ejection of the recording head, or has been subjected to a treatment for avoiding such an effect. Meanwhile, it is also desirable to take into account productivity of the ink cartridge. For example, the ink cartridge is manufactured by dividing the cartridge body into a bottom portion 11 and an upper portion, and integrally molding the same with a resin material, respectively, and bonding the bottom portion 11 and the upper portion together after applying a vacuum-generating material thereto. If such a resin material is transparent, or translucent, the ink in the ink tank can be observed from the outside, and therefore, the time for replacing the ink cartridge can be easily judged. To facilitate bonding of the above-described sealant and the like, it is desirable to provide a projection as shown in the drawings. The outer surface of the ink cartridge may be granular from the appearance point of view.

The ink may be injected by a pressurization or depressurization method. It is preferable that the ink tanks are provided with ink injection ports so that other openings are not contaminated during the ink injection operation. After the ink is injected, the ink injection port is preferably covered with a plastic or metal plug.

The structure and shape of the ink cartridge may be changed within the scope of the invention.

And others.

The ink tank (ink cartridge) in the above embodiment may be replaceable or integrated with the recording head.

When the ink tank is replaceable, it is preferable that the host machine detects the replacement of the ink tank and the recovery process (e.g., the suction process) is performed by an operator.

As shown in fig. 4, this ink tank can be used in an ink jet printer in which 4 recording heads are connected to form a recording head 20 connectable to 4 color ink tanks Bkla, Clb, Mlc, Yld.

Comparative example 1

A comparative example in which the internal pressure of the ink supply portion of the ink tank is varied depending on the ink supply surface will be described.

There is no passage for introducing air in the ink tank, and inside the material tank for generating vacuum there is an absorbing material with micro pores and with a substantially uniform size distribution.

As shown in fig. 14, in the initial stage, the ink tank 6 is substantially filled with ink, and a certain amount of ink is also contained in the material tank in which the vacuum is generated. When the ink supply is started from this state, the ink is discharged from the material tank 4 where the vacuum is generated, and therefore, an internal pressure is generated in the ink supply portion by the balance between the static pressure head of the ink and the capillary force of the top surface (gas-liquid interface) of the ink of the absorbing material 3 in the material tank 4 where the vacuum is generated. As the ink continues to be output, the top surface of the ink drops. Therefore, the negative pressure increases significantly with the height of the ink, and reaches the state shown by the symbol "a" in fig. 13. The negative pressure of the ink supply portion is increased until the ink supply surface forms a gas-liquid interface (meniscus) at the gap at the bottom of the ink chamber.

The ink surface in the adsorbing material is greatly lowered until a state where a meniscus is formed at the gap, and, as the case may be, the ink surface may be lowered beyond a connecting portion with the recording head.

In this way, air enters the recording head, causing unstable ink ejection or non-ink ejection.

Even if this is not achieved, the internal pressure in the ink supply portion may increase beyond a predetermined negative pressure determined by the pore size of the absorbent material at the void, as shown at b in fig. 13. The reason is as follows: the absorbent material is more or less compressed by the surrounding inner walls of the material tank creating the vacuum, but there is no wall in the space and the absorbent material is not compressed, as a result of which the compression is somewhat smaller here than in the other parts. Therefore, this is shown in fig. 12.

This is shown in the figure, where a portion of the ink in the canister 4 creating the vacuum has been consumed. As the ink continues to be consumed in this case, then the meniscus R4 corresponding to the largest pore size among R2, R3, and R4 in the absorbent material 3 moves a distance greater than the menisci in R3 and R4. As the meniscus approaches the gap, the surface tension suddenly decreases, and as a result, the meniscus enters the ink tank, the meniscus breaks, and air enters the ink tank. At this time, only a small amount of ink is transferred from R₃And R₄These two parts are supplied out of R instead of from R₂This portion is output. The pressure loss δ P is considerable when the meniscus moves.

However, when the meniscus which once fractured is restored, it is restored by inertia at a position close to the original position, and therefore, the state of high pressure loss continues for a while.

Until the meniscus has a pore size R₁All stabilizing, the same course of action is repeated. Once the meniscus has stabilized at the gap, the bubble enters the ink reservoir until the gap is filled by the pore size R at the gap₁The determined negative pressure is established and a steady state is reached.

The above process is shown in figure 13.b, in which stage ink can be delivered from either the ink tank or the absorbent material. If the air introduction passage is not particularly provided, the internal pressure of the ink supply portion becomes unstable, and the pressure loss δ p of the ink supply increases, so that the ink ejection performance is not good, with the result that it is difficult to perform high-speed printing.

Example 2

FIG. 5 shows another embodiment of the apparatus.

In this embodiment, two ribs 61 are provided on the partition rib 5 of the material tank 4 where the vacuum is generated. An air introduction passage a51 is formed between these two ribs and the absorbent material 3. The bottom ends a of the ribs 61 are positioned higher than the bottom ends B of the ribs 5 so that the space 8 is covered by the absorbent material 3 simply by placing a rectangular parallelepiped absorbent material 3 into the vacuum-producing can 4. Therefore, the air introduction passage a51 can be easily and stably extended to a position very close to the gap 8. Arrow a52 indicates the direction of air flow.

With this ink tank, the printing process can be efficiently performed, and it has been confirmed that the ink surface and meniscus shown in fig. 5 can be formed quickly due to the ink supply surface caused by the recording work, and that rapid replacement between air and ink can also be achieved by the break of the meniscus. Therefore, the ink can be supplied with only a small pressure loss, and thus a high-speed printing process can be stably realized.

Example 3

Fig. 6 shows a device of a third embodiment in which the number of ribs 71 is increased, thereby increasing the number of air introduction passages. The ribs 71 are arranged to separate the canisters of material from which a vacuum is to be created. According to this embodiment, the plurality of air introduction passages can provide a stable air flow from the air vent 13 to the vicinity of the gap 8, so that, as in the first and second embodiments, ink supply can be realized with little pressure loss, and a high-speed printing process can be stably realized.

In the present embodiment, even if the passage port 13 is disposed at a place distant from the gap 8, the air can be smoothly introduced.

Example 4

Fig. 7 shows an apparatus according to the 4 th embodiment of the present invention.

In the present embodiment, similarly to the embodiments 2 and 3, the ribs 81 are provided on the partition rib to form the air introduction passages a 71. The ribs 81 are asymmetrical with respect to the rib 5, so that the passage of ink from the ink tank 6 into the material tank 4 for generating vacuum through the gap 8, corresponding to the passage of the ink flow a72, along the air introduction passage a71 into the air flow a73 of the ink tank 6 through the gap 8, is formed independently of each other with respect to the center line a, so that the pressure loss due to the exchange can be reduced.

More specifically, this structure can effectively reduce the pressure loss δ p required for the exchange between ink and air by about half.

Thus, the ink can be stably ejected from the recording head.

Example 5

Fig. 8 is another embodiment of the device, which is provided with ribs 91. In embodiments 2 to 4, the top end of the rib 91 extends to the upper part of the inner surface of the wall of the material tank 4 accommodating the vacuum generation, and in the present embodiment, the rib 91 does not extend to such an extent. Thus, the top of the absorbent article is not compressed by the ribs 91, and surface tension can be readily generated in this compressed portion, further stabilizing vacuum control.

More specifically, the ink is supplied from the absorbing material 3 before the ink surface a81 in the absorbing material 3 (the vacuum-generating material 3) moves to the stable ink surface a82 where the ink starts to be supplied from the ink tank in the initial state. This is because if the air 82 for gas-liquid exchange by the air introduction channel advances too fast, the consumption of the ink in the absorbent member 3 becomes slow, and as a result, the ink is supplied from the ink tank. Thus limiting the amount of ink that can flow from the ink tank 6 into the vacuum producing material tank 4 when environmental conditions change, such as pressure changes. The cushioning effect of the absorbent material 3 against ink leakage is then deteriorated. In the present embodiment, since the air introduction passage a83 is provided in the above-described manner, air is introduced only after the ink in the absorbent material 3 is consumed to some extent, in such a manner as to control the ink surface of the absorbent material 3, thereby improving the resistance against ink leakage.

Example 6

Fig. 9 shows another embodiment.

In this embodiment, the air introduction passages are formed by slots 100 in the spacer ribs or walls.

According to the present embodiment, the compressibility of the absorbent contained in the tank for generating vacuum is reduced, and therefore, it is easy to control the degree of vacuum, and thus ink can be stably supplied.

Example 7

Fig. 20 shows yet another embodiment.

The construction is similar to the embodiment of figure 6, however, the air introduction passages extend to the bottom end of the rib, unlike in figure 6.

Similar to examples 5 and 6, the ink in the absorbent material 3 is consumed before the ink surface of the absorbent material 3 in the ink tank at the initial stage of ink consumption moves to the stable ink surface position on the end C of the air introduction path a 201. Thus, the ink in the ink tank 6 is consumed, and the air-liquid exchange is performed through the air introduction passage. This configuration is comparable to the version shown in fig. 21, since the air introduction channels extend to the bottom end of the ribs. A detailed description will be given in describing the version in fig. 21.

The absorbent material 3 can be considered to be the hairrein shown in figure 20. The air introduction passage a201 leads from the C portion to the bottom end of the rib, and it can be considered that the air introduction passage a201 is in turn communicated with the capillary at the upper portion of the C portion.

As described above, in the initial stage of ink supply, the ink surface in the absorbent material 3 is at a certain height. However, this surface gradually falls as the ink is consumed. The internal pressure (negative pressure) in the ink supply portion gradually increases.

When the ink is consumed to the height C of the top end of the air introduction path a201, a meniscus is formed at the position D of the capillary. As the ink is further replenished and consumed, the meniscus of the ink, i.e., the ink surface, drops again. If the ink surface tension of the air introduction path is suddenly lowered by lowering to the position of E, the ink in the air introduction path can be consumed directly. Thereafter, ink is consumed from the ink tank to maintain this position. That is, gas-liquid exchange is highlighted. In this way, the ink surface is stabilized at a position slightly lower than the height C during consumption of the ink, and thus, the internal pressure of the ink supply portion is stabilized. When ink supply is stopped, the meniscus in the capillary tube is restored from the position E to the position D, thereby being kept stable.

As previously described, the ink surface in the wicking material moves back and forth between positions D and E until the ink tank is completely depleted of ink. In the drawing, a202 denotes an ink supply period, and a203 denotes a non-ink supply period.

Thereafter, the ink is supplied from the material that adsorbs the ink. Thus, the internal pressure (vacuum) of the ink supply portion increases, and ink becomes non-supplied.

The internal pressure of the ink supply portion causes a pressure difference between the capillary force of the absorbent material 3 (the height to which the absorbent material can suck the ink) and the ink surface height in the absorbent material 3, and therefore, the height is set at a predetermined height with respect to the ink supply portion 6. From this point of view, it is desirable that the pore size of the absorbent material 3 is relatively small.

The reason why the height C is set to a predetermined height with respect to the ink supply portion 6 is that if the ink surface is lower than the ink supply portion 6, air enters, causing abnormality in ink ejection.

However, the height is not desired to be higher than the predetermined height because the internal pressure in the ink tank is changed due to a change in the environmental conditions, and thus, when the amount of ink flowing from the ink tank into the absorbent member is excessive, the cushioning effect is lowered. In view of the above, the volume of the absorbing material above the height C should be selected to be approximately half the volume of the ink tank.

The above-mentioned mechanism will be explained in detail below.

The absorbent material is generally considered to have a uniform density. The internal pressure (vacuum or negative pressure) in the ink supply part is determined by the height difference H₁-H₂In which H is₁Is the height to which the capillary force of the absorbing material can draw ink from the ink supply, and H₂Is the height to which ink has been drawn up from the level of the ink supply portion.

For example, the suction force of the absorbent material is 60mm (H)₁) And the height of the air introduction passage A from the ink containing portion is 15mm (H)₂) Therefore, the internal pressure of the ink supply part is 45mm, and the height of the water column is 60mm-15mm H₁-H₂。

In the initial phase, as the ink is consumed from the absorbent material, the level of the liquid surface decreases accordingly, while the internal pressure decreases greatly in a straight line.

When the ink tank of the above structure is employed, the ink can be stably supplied by means of vacuum.

The structure of such an ink tank is itself simple, and it can be easily manufactured with a mold or the like, and thus a large number of ink tanks can be stably manufactured.

When the ink is consumed to such an extent that the height of the ink surface in the absorbent material is in the air introduction path a201, that is, the C position, in other words, the ink surface is in the E position, the meniscus in the air introduction path a201 is not maintained, and the ink is absorbed into the absorbent material, and the air introduction path is formed. Then, gas-liquid exchange takes place immediately. On the other hand, the liquid level in the absorbing material rises because ink is absorbed from the ink tank, thereby forming a liquid level D, and the gas-liquid exchange stops. In this state, the air introduction passage a201 is filled with ink, and the absorbent material above the air introduction passage in the mold simply functions as a valve.

If the ink is consumed again in this state, the liquid level in the absorbent material rises only a little bit, which corresponds to opening the valve, so that an immediate gas-liquid exchange takes place, so that the ink is consumed from the ink tank 6. When the ink consumption is completed, the liquid level in the adsorbing material rises due to the capillary force of the adsorbing material. When rising to the D position, the gas-liquid exchange stops, and the liquid level stabilizes at that position.

Therefore, the liquid level of the ink can be controlled by the height of the air introduction passage a201 in such a manner that (the height of the portion is stably controlled and the capillary force of the absorbing material, that is, the suction height of the ink is adjusted in advance), and in this way, the internal pressure of the ink supply portion can be easily controlled.

In order not to cause excessive flow of ink from the ink tank 6 into the absorbent material 4 when the internal pressure of the ink changes due to changes in environmental conditions, the capillary force of the absorbent material, i.e., the suction height of the ink, is increased, whereby overflow of ink from the ink tank can be prevented and positive pressure at the ink supply portion can also be prevented.

Example 8

FIG. 21 is a longitudinal sectional view of an ink cartridge for an ink jet recording apparatus according to example 8 of the present invention. Fig. 22 is a cross-sectional view thereof, and fig. 23 is a sectional view showing one surface of the rib.

An air introduction groove 1031 and a vacuum-generating material regulation chamber 1032 are formed in the rib 1005 serving as a partition wall between the ink tank 1006 and the vacuum-generating material tank 1004. The air introduction groove 1031 is formed in the material groove 1004 that generates the vacuum, and extends from the center portion of the rib 1005 to one end of the rib 1005, that is, to the empty space 1008 formed in cooperation with the bottom 1011 of the ink cartridge. A vacuum-producing material adjustment chamber 1032, which is recessed, is formed in the vicinity of the vacuum-producing material 1003 and the air introduction path 1031 on the rib 1005.

Since the vacuum-generating material 1003 is in contact with the inner surface of the vacuum-generating material tank 1004, that is, the vacuum-generating material 1003 is unevenly pressed into the material tank 1004, a part of the original contact pressure (compression) with respect to the vacuum-generating material 1003 is relieved. As shown in fig. 21 and 22. Therefore, when the recording head starts consuming the ink, the ink present in the material 1003 generating vacuum is consumed first, and is consumed to the adjustment chamber 1032. If the ink is further consumed, the air can easily break the meniscus of the portion of the material 1003 where the contact pressure of the vacuum is reduced by the presence of the regulating chamber 1032, and quickly enter the air introduction path 1031, thereby making it easier to control the vacuum.

In this embodiment, it is necessary to use a porous material having elasticity as the vacuum generating material 1003.

The capillary force of the vacuum-generating material 1003 itself (surface tension at the interface of the ink and the vacuum-generating material) can be used to prevent the ink from leaking out of the ink jet recording head when the recording operation is not being performed.

FIGS. 29 to 31 show, as a comparative example, an example of an ink cartridge having no regulating chamber for generating a vacuum material.

Even if the comparative example is an ink cartridge, a normal operation process can be achieved without any problem in a general state by the mechanism described below. Since the air introduction passage is provided, stable operation can be achieved.

However, in order to further stabilize the working process, or to be able to use a porous resin material having continuous micropores as a material for generating negative pressure, further control of the stability of the working thereof is required.

As shown in an enlarged sectional view of fig. 32, the material 1003 generating vacuum (or negative pressure) is in contact with the ribs 1005, and a part thereof enters the air introduction grooves 1031. If so, the contact pressure (compressive force) against the material 1003 at the contact portion a is not reduced. This makes it difficult for air to break through the meniscus of the ink and enter the air introduction path 1031. If so, even if the ink continues to be consumed, no air-liquid exchange occurs, and the air introduction path does not function. There is a disadvantage that the ink cannot be supplied from the material adsorbing the ink.

This embodiment is preferable in this respect as compared with comparative example 2 described above.

Example 9

FIG. 24 is a longitudinal cross-sectional view of two ribs 1005 having different cross-sectional portions. Fig. 25 is an enlarged cross-sectional view of one rib.

As shown, the shape of the vacuum generator adjustment chamber 1032 and the air inlet slot 1031 are different from those of embodiment 8:

in particular the stepping position of the ribs 105 in contact with the vacuum creature 1003 is performed around, thereby further suggesting the effect of pressure contact and compression variation.

Adjacent to the rib 1005, adjacent to the container 1004, there is a curved surface R through which air is drawn into the ink by the substance 1003 and into the ink tank 1006. Ink entering the ink tank with air is fed into the substance chamber 1006. In the context of air-liquid exchange, air is introduced into the ink in the substance 1003.

In order to make the air-liquid exchange smoother, it is preferable that the pressure contact between the substance 1003 and the substance containing chamber is located at the lower part of the air-liquid exchange range, not at the upper part.

This is because the flow of air from the gas phase ink phase is smoother, which is achieved by the air passing through the bladder tube of the vacuum pressure object 1003, the contact force of which is released.

For example, the desired effect can be obtained by generating a form of vacuum adjusting chamber by a portion of the middle of the rib 1005 at the end of the air introduction part.

The shape of the vacuum generating substance adjusting chamber 1032 may be varied to achieve the same function, and the shape and size may be varied to achieve the above requirements.

As described above, according to the present embodiment, the air and the ink in the ink tank are smoothly and stably exchanged with the ink feeding process, and as a result, the internal pressure of the ink supply portion can be stably controlled, which enables the recording head to perform high-speed, stable ink ejection.

Further, the ink tank does not generate a dripping phenomenon even if the pressure inside thereof is changed due to a change in external conditions.

Example 10

The ink tank 2001 in this embodiment is a combined form in which the inside is divided into two chambers a and b, which communicate at the bottom, and is characterized in that an ink absorbing material 2002 having an adjusted bladder force is placed in a without a gap, thereby providing an air passage 2003.

In the situation shown in fig. 15, the ink that can be supplied has been fed from the chamber 4 and is consumed to half in the case where the ink in the chamber 6 has been filled from both chambers 4 and 6. In fig. 15, the ink in the compressed ink absorbing material 3 is maintained at a height at the same level as the ink ejecting portion stationary head on the recording head, the vacuum in the chamber 6 and the bag force of the compressed ink absorbing material. When the ink is replenished from the ink supply portion, the amount of ink in the chamber 4 is not reduced, and the ink in the chamber b is consumed, i.e. -the amount of ink supplied from the ink chamber 6 into the ink chamber 4 is made to correspond to the amount supplied from the ink chamber 4, and such corresponding replenishment is achieved by maintaining the internal pressure balance. In correspondence with the above, air is introduced through the ink chamber 4 and the air passage.

Now, as shown in fig. 15, air and ink are exchanged at the bottom of the ink chamber and as air enters the chamber 6, the meniscus formed by the ink absorbing material in the chamber 4 is blocked by the part close to the chamber 6 and the pressure in the chamber 6 is balanced by the above-mentioned meniscus holding force generated by the compressed ink absorbing material. The replenishment of ink and the generation of internal pressure in this combination will be described in greater detail with reference to fig. 2. When the ink in the chamber 4 is consumed to a predetermined extent, the portion of the compression ring of ink absorbing material adjacent the chamber wall will communicate with the air passage, thereby creating a meniscus when acting against atmospheric pressure. The internal ink pressure at the ink supply portion is maintained by the compressed ink absorbent material adjacent the ink chamber walls, which pressure is adjusted to balance the predetermined bladder forces caused by the appropriate compression. The closed space at the top of the chamber 6 is balanced by the forces of the bladder compressing the ink absorbing material adjacent the chamber walls before the ink flows out, and the meniscus formed by the ink static head and the compressed ink absorbing material remaining in the ink chamber b is maintained by the reduced pressure. When ink is supplied to the recording head through the ink supply portion in this case, the ink flows out of the ink chamber 6, the pressure in the chamber 6 is further reduced by the ink consumption, and at this time, the meniscus formed by the ink absorbing material at the bottom of the ink chamber wall is partially broken, and air can enter the ink chamber from the broken portion, with the result that the excessively reduced pressure in the chamber 6 is balanced by the meniscus holding force of the compressed ink absorbing material and the stationary head of the ink itself in the chamber b. In this manner, the internal pressure of the ink supply portion is maintained at a predetermined level by the bladder force of the compressed ink absorbing material near the bottom of the ink chamber wall.

Fig. 34 shows the function of the compressed oil absorbing material as a buffer. The state shown in the figure is that in the case shown in fig. 15, air in the ink chamber 2006 expands due to a temperature rise or a reduction in atmospheric pressure, or the like, and ink in the ink chamber 2006 flows out into the ink chamber 2004. The ink flowing into the chamber 2004 is retained in the compressed absorbent material 2003 in this embodiment, and the correlation between the ink absorption amount of the compressed ink absorbent material and the ink chamber is determined based on the fact that ink dripping is not generated when the environment or temperature changes. The maximum ink absorption in ink chamber 2004 is set with reference to the amount of ink that flows out of chamber 2006 in the worst possible situation, and the amount of ink that remains in chamber 2004 as ink flows in 2006 into 2004. Ink chamber 2004 should have little space to hold ink that can be absorbed by the compressed absorbent material. Fig. 65 shows coordinates in which a solid line indicates the relationship between the initial accommodation space of the chamber 2006 before the pressure is reduced and the amount of ink flowing out when the pressure is reduced to 0.7 atm. In this figure, the broken line indicates the case when the maximum pressure drop is 0.5 atm. With respect to estimating the worst case amount of ink flowing out of chamber 2006, the maximum amount of ink flowing out of chamber 2006 is at a maximum pressure of 0.7 atmospheres, when 30% of the ink holding the scents remains in chamber 2006. If the ink below the bottom end of the chamber wall is also absorbed by the compressed absorbent in the chamber 2004, it is believed that all of the ink remaining in 2006 (30% capacity) is dropped out. When the worst case is 0.5 atmospheres, 50% of the volume of chamber 2006 flows out. The expansion of air in chamber 2006 due to the pressure drop is greater if the amount of ink is left smaller. Thereby more ink can be pushed out. However, the maximum amount of ink that flows out of chamber 2006 is lower than the ink volume in chamber 2006, and therefore, at the assumed 0.7 atmosphere, when the amount of ink left in the chamber is no more than 30%, the amount is lower than the air expansion volume. The result is a reduced amount of ink flowing into chamber 2004. Thus 30% of the volume of chamber 2006 is the maximum ink drop leakage (50% at 0.5 atmosphere). The above applies to the case of temperature change, but even if the temperature is increased by 50 ℃, the amount of ink flowing out is smaller than that in the case of the above-described pressure decrease.

If, conversely, the atmospheric pressure rises, the difference between the low pressure air caused by the stationary head above the chamber 2006 and the increased ambient pressure is large, there is a tendency to return the pressure difference to the predetermined difference by venting air or ink into the chamber 2006. In this case, similar to the practice of supplying ink from the chamber 2006, the meniscus formation of the compressed ink absorber 2003 near the bottom end of the chamber wall 2005 is broken, so that air is mainly introduced into the ink chamber 2006 to form a pressure equilibrium state, whereby the internal pressure of the ink supply portion is hardly changed without exerting any other influence on the recording apparatus, and in the foregoing example, when the ambient pressure is returned to the original state, the amount of ink corresponding to the air introduced into the chamber 2006 flows from the chamber 2006 into the chamber 2004. Thus, similar to the previous embodiment, the amount of ink in chamber 2004 temporarily increases as the air-liquid interface rises. Therefore, similarly to the initial state, the internal pressure of the ink is also temporarily slightly higher than that in the steady state, but the influence of this on the ink ejection characteristics of the recording head is small enough to be disregarded. The above-described problem arises in such a case, for example, a recording apparatus used in a low-pressure environment such as a place with a higher altitude is moved to a low-altitude area. Even in this case, the only change in the invention is that air enters the chamber 2006. When the recording apparatus moves to an area with a higher altitude again, what happens is only a slight increase in the internal pressure of the ink supply portion. There is no practical problem because the use of the device is not feasible in the case of excessively higher than atmospheric pressure.

The ink is reliably retained in the ink chamber 2004 by the compressed ink absorber 2003 until the change is made at the start of use, because the ink chamber 2006 is closed, there is no leakage from the openings (air passage and ink supply portion), and thus it is easy to use

The desired operating conditions for the ink chamber structure and the compressed ink absorber of the present hybrid variety of ink tanks will be described as follows:

the relationship between the ink absorption amount of the compressed ink absorber 2003 and the ink chamber structure is considered based on the fact that ink leakage does not occur when the surrounding environment changes. The maximum ink absorption of chamber 2004 is determined based on the amount of ink that flows out of chamber 2006 under worst case conditions and the amount of ink that remains in chamber 2004 when chamber 2006 supplies ink into chamber 2004. The ink chamber 2004 should have a space that accommodates at least the maximum amount of oil that the compressed absorbent can absorb. Regarding the estimation of the amount of oil that can flow out of the ink chamber 2006 under worst-case conditions, when the pressure drops to 0.7 atmospheres, the amount of ink that flows out of the ink 2006 is at a maximum, leaving 30% of the space in the chamber 2006. If ink below the bottom of the chamber wall is also absorbed by the compressed absorber in chamber 2004, it is believed that ink left in ink chamber 2006 (30% space) has leaked out. When the worst condition reaches 0.5 atmospheres, 50% of the volume of chamber 2006 is out of the ink. The less the amount of ink that is spent, the more the air in chamber 2006 expands due to the reduced pressure. Whereby a large amount of ink is discharged. But the maximum amount of ink that flows out is less than the amount of ink contained in ink chamber 2006. Thus, assuming 0.7 atmospheres, when the remaining ink is not more than 30%, the amount of ink remaining is smaller than the space occupied by the expanded air, and the amount of ink in newly flowed chamber 2004 is reduced. Thus, 30% of the space in chamber 2006 is the maximum leakage of ink (50% at 0.5 atmospheres).

The size of the channels between the ink chambers formed at the bottom of the ink chamber wall 2005 is no smaller than the size that ink in chamber 2006 cannot form at the channels. The chamber 2006 is closed above. As in the first case described. The dimensions are selected in consideration of the properties of the ink, such as viscosity, to smoothly perform air-liquid exchange while passing through the passage port at the maximum flow rate (ink supply rate at which the recording apparatus is stably operating for printing or absorbing) supplied from the ink supply portion. However, this consideration is to be paid attention to the fact that when the upper surface of the ink remaining in the chamber 2006 is lower than the bottom of the ink chamber wall 2005, the internal pressure of the ink supply portion temporarily changes in the positive direction as has been described above, and the size is selected so as to avoid the influence of this factor on the ink ejection quality of the recording head.

As described for the operation of the ink tank, in this ink tank of the mixed type, the internal pressure at the ink supply portion is held by the compressed ink absorber near the wall of the ink chamber, and therefore, the bag force of the compressed ink absorber 2003 near the bottom end portion of the ink chamber 2005 can be appropriately adjusted in order to maintain the desired internal pressure at the time of supplying ink from the chamber 2006. In particular, the compression ratio or starting pore size is selected such that the bladder force of the compressed ink absorber 2003 near the bottom end of the ink chamber wall 2005 is capable of generating the internal pressure required for the recording process. For example, the pressure of the compressed ink absorber 2003 near the bottom end of the chamber wall 2005 when the internal ink pressure of the ink supply portion is-h (mmaq) may be sufficient to generate a bladder force that draws h mm. If simplified, theConstruction of compressed ink-absorbing substances, fine pore diameter P thereof₁Can satisfy P₁The relationship 2 γ cos θ/ρ gh. ρ represents the specific gravity or density of the ink, γ is its surface tension, θ represents the angle at which the absorbing substance is in contact with the ink, and g represents gravity.

When the air-liquid interface of the ink in the chamber 2004 is lower than the upper end of the ink supply portion during the ink is supplied from the chamber 2006, air enters the recording head. Therefore, the interface should be maintained higher than the upper end of the ink supply portion. Thus, the compressed ink absorber 2003 located above the ink supply portion obtains a cell force capable of absorbing (h + i) the height of the ink, where i represents the distance i mm from the air-liquid interface above the top of the ink supply portion. Similar to the above, if the structure of the compressed ink-absorbent article is simplified, the fine pore diameter P thereof₂Should satisfy P₂＝2γcosθ/ρg(h+i)。

The height i (mm) in the above equation is preferably higher than the tip of the ink supply portion. The ink absorption (bladder force) decreases gradually (if the absorbent material is the same, the pore diameter P is smaller₃Gradually increasing) (fig. 35), or the overall force of the compressed ink absorber is reduced to only near the ink chamber wall 2005 (fig. 36), so that the air-liquid interface also gradually decreases towards the ink chamber wall, which is located inside the absorber 2003 in the chamber 2004. The change in balloon force is consistent with the balloon force at the bottom of the chamber wall 2005 (if the same material is used, P is satisfied)₁)。

If the ink tank is not subjected to impact tilting, temperature spikes, or other particular external forces, the bladder tube force of the portion of the absorbent 2003 underlying the air-liquid interface may be any amount. However, in order to provide the ink remaining in the chamber 2004, even if such external force is conducted or the ink in the chamber 2006 is completely exhausted, the bladder tube force gradually increases toward the ink providing portion (pore diameter P of the fine pore)₄) This increase is compared to the bladder force (fine pore size P) at the bottom of the ink chamber wall 2005₁) To achieve a larger (fine pore diameter P) in the ink-providing portion₅) (FIG. 37). Namely, it isThe adjustment of the balloon tube force should be adapted to: the force of the bag tube at the end of the chamber wall should be less than the force of the bag tube immediately above the ink supply portion, preferably in the relationship of (the force of the bag tube at the bottom end of the chamber wall) < (the force of the bag tube at the lower part of the middle part of the ink chamber) < (the force of the bag tube at the upper part of the middle part of the ink chamber) < (the force of the bag tube at.

If the structure of the compressed ink absorber 2003 is simplified such that the ratio of the i of the pores satisfies P₁＝P₂Preferably P₁＞(P₃P₄)＜(P₂P₅)。

P₃And P₄Relation of (A) and P₂And P₅May be consistent in terms of compression ratio, such as: p₃＜P₄，P₂＜P₅Or P is₃＝P₄Or P₂＝P₅。

Referring to FIGS. 35, 36 and 37, examples of selected compression ratios are shown. In this case, the above-described relationships can be satisfied by selecting the same ink absorber 2003 and adjusting the compression ratio. In the figure, a351, a361, a371, represent the air-liquid interface, while arrows a352, a362 and a372 represent the compression ratio of the ascending compressed ink-absorbent.

FIG. 38 shows a comparative example 3 in which the bladder force of the compressed ink absorbent 2003 is no greater at the ink supply than near the chamber wall. This figure shows a situation where ink has been provided from chamber 2004, partially shown. In this comparative example, the air-liquid interface A381 is formed near the bottom portion of the ink chamber wall 2005, and the conduction portion between the chambers 2004 and 2006 is on the air phase side. In this case, the ink can no longer be supplied from the chamber 2006, and the air introduced through the air passage portion 2013 is directly fed to the recording head through the ink supply portion, at which time the ink tank cannot be continuously operated.

FIG. 39 shows a comparative example 4 in which the bag tube force compressing the ink absorber 2003 near the bottom end portion (FIG. 39(B)) or the wall side (FIG. 39 (A)) is opposite to the force of the ink supply portion as compared to the embodiment of the present invention similar to comparative example 3, before the air-liquid interface A391 is formed near the bottom end of the wall 2005, the air-liquid interface falls below the top end of the ink supply portion, so that ink cannot be supplied from the chamber 2006, whereby air entering through the air passage 2013 is directly supplied to the recording head, and the ink tank also cannot operate.

The foregoing description was about a monochrome recording apparatus having one recording head. The embodiments described are also applicable to a recording apparatus with 4 recording heads (e.g., BK, C, M, and Y) for one color ink ejection, which can eject inks of different colors; and also to a recording apparatus for ejecting 4 color inks with one recording head. In this case, a facility is required to be added to limit the attachment position and direction of the replaceable ink tank.

In the foregoing embodiments, the ink tanks are replaceable, but these examples are applicable to a recording head disk that integrates a recording head and an ink tank.

Example 11

Fig. 40 and 41 show a device according to embodiment 11. The addition of two ink chambers 2008 and 2009 is placed in communication with chamber 2006. In the example of this variant, the order of consumption of the inks is: ink chambers 2006, 2008, and 2009. In this variation, the ink chamber is divided into 4 chambers to better prevent the leakage phenomena caused by environmental, pressure drop and temperature variations described in the previous examples. If the air in chambers 2006 and 2008 expands in the condition of FIG. 41, the expanding portion of the air in chamber 2006 is released through chamber 2004 and air channel 2013, while the expanding portion in chamber 2008 enters chamber 2006 and to chamber 2004 by the flow of ink. The cavity 2004 then has a cushioning function. The ink holding capacity of the ink absorber in the chamber 2004 may thus be determined based on the amount of leakage from one chamber. The volume of the compressed ink absorbent 2003 can be reduced to be smaller than that in example 10, so that the ink holding amount can be increased.

Example 12

Fig. 42 shows an embodiment 12 in which the compressed ink absorbent in ink chamber 2004 is divided into 3 sections, each section having a particular function. In fig. 42, the compression ratio of the compressed ink absorbent near the ink supply portion (which occupies most of the space in 2004) is relatively high to increase the bladder force. The compression ratio of the absorbent near the end of the chamber is low but sufficient to provide sufficient bladder force required to produce the internal pressure required to provide the ink (a423 indicates a relatively low compression ratio). Furthermore, a substance a424 is placed along the chamber wall even with a smaller compression ratio to promote the formation of an air-liquid interface a421 at the bottom end of the chamber. In this embodiment, the compressed ink absorbent 2003 is divided into 3 sections, compressed in advance, and then set. Doing so makes the ink tank manufacturing process somewhat more complicated, but the compression ratio (and thus the bladder force) can be adjusted to the appropriate degree at the corresponding position. In addition, the low bladder force absorber described above is disposed on the lateral wall of the chamber, thereby allowing the internal pressure of the ink supply portion to rise more quickly to a predetermined level.

Example 13

Fig. 43 shows a 13 th embodiment. Similar to example 12, the compressed ink absorber 2003 is divided into 3 pieces, part a432 has a high compression ratio, part a434 has a low compression ratio, and a portion a433 with a small compression ratio (intermediate bladder force) is located at the bottom of the chamber 2006. In this embodiment, even if the ink level in the chamber 2006 becomes lower than the bottom end of the chamber wall 2006, entry of ink into the chamber 2004 can be suppressed. Thereby reducing the change in the internal pressure of the ink supply portion. Thereby, the degree of communication between the cavities can also be increased, thereby slightly reducing the restriction in the ink tank. In this figure, a431 represents the air-liquid interface. However, in this embodiment, as shown in FIG. 44, if the ink-absorbent article is installed, further compressing partially (P441) its portion on the bottom end of the chamber wall, the compression ratio near the chamber 2006 will be locally higher, causing a local increase in the capsular tube force. There is then a possibility that air is blocked between locations near the chamber 2004 with a normal compression ratio, whereby a smaller bladder force causes a meniscus to form, preventing ink from being provided from the chamber 2006. These should therefore be avoided.

As described above, according to embodiments 10, 11, 12, and 13, the hybrid type ink tank is improved to provide an air passage to a supply portion of the recording head. And further provides an ink supply chamber containing a compressed ink absorbent for adjusting the force of the bladder tube, and one or more ink chambers communicating therewith. The bag tube force of the ink absorber is larger than the bag tube force of the absorber at the cavity communicating part at least at the upper part of the ink supplying part of the recording head, thereby stable ejection can be maintained and leakage can be prevented. Thus, the ink can be handled easily, and the ink retention is high.

Example 4

During the pressure drop test of the aforementioned ink tank, a problem was found that the ink caused a leakage phenomenon when the ink had a composition of comparative ink 3 to be described later. Therefore, the leakage prevention means varies depending on the individual ink tanks. Various investigations and tests by the inventors have suggested that the damping effect of the ink is affected by the co-whining between the ink and the tank.

Fig. 14, 45 and 46 show a comparison of ink tanks that develop leaks. In fig. 45, (I) shows a range in which the ink absorbent has not been contacted with the ink, (II) shows a range in which the ink has been absorbed once, and (III) shows a range in which the ink is contained. Fig. 14 shows the initial state of the ink tank, and fig. 45 shows a state where the available ink in chamber 3004 has been consumed, when only 1/5 ink is in chamber 3006. Fig. 46 shows that the ambient pressure increase or temperature change that occurs in the state of fig. 45 causes the air in the cavity 3006 to expand. Thereby allowing time for the ink in the cavity 3006 to be discharged into the cavity 3004. A portion of the ink is absorbed by the portion of the absorber that has absorbed the primary ink, but additional ink is not absorbed by the portion, but leaks out of the air passage 303 along the ink tank walls or gaps between the walls and the ink absorber.

The reasons for the above phenomena can be considered as follows: the ink absorber that has never absorbed ink exhibits a weak absorption capacity. The ink-absorbing substances that absorb the ink have different surface states that facilitate the absorption of the ink. These have been confirmed in the following manner. An unused compressed absorbent (polyurethane foam) and a compressed absorbent absorbing ink once were immersed in the ink, and the ink absorption height was measured. (As a result, it was found that the former hardly absorbs ink (several millimeters), and the latter absorbs several centimeters, thus confirming their remarkable difference in absorption characteristics. on the ink disk of the present embodiment, ink can be injected into the cavity 3006 to the volume limit of its initial state. furthermore, ink can also be injected into the cavity 3004 to the amount limit of its retention.

After the tank is separated, the oil in the cavity 3004 is consumed, and thereafter the oil in the cavity 3006 is consumed. When the oil in the chamber 3006 having the buffering function is consumed, the ink absorbent in the chamber 3004 is wetted, whereby it can easily absorb the ink, and the buffering function is also performed, thereby effectively preventing the outflow of the ink from the air passage. Such an oil tank was mounted on an ink jet recording apparatus, and the pressure drop thereof was measured. As a result, it was found that any oil tank did not leak oil, and the recorded printing results were of high quality.

To make an ink tank having the above-described function, it is considered that the ink absorber is subjected to an ink wetting treatment with light or other medium having a property to be wetted and then filled into the oil tank. However, this may require a drying step or the like, and if a medium other than the ink is used, it is considered possible whether such a medium dissolved in the ink may cause damage to the heater. It is also contemplated to use an ink that better cooperates with the absorbent. However, such inks generally have good bleed properties, and therefore, low-print inks bleed randomly along fibers on the paper, reducing print quality.

Fig. 47 and 48 show a variant embodiment of the invention. In the figures, (I), (II) and (III), the contents are shown similarly to those of (I), (II) and (III) of FIG. 45. In this example, there are two ink chambers 3007 and 3008, which communicate with chamber 3006, and in this example the sequence of ink consumption is: cavities 3006, 3007 and 3008. In this modified example, the ink chamber is divided into 4 chambers to prevent the oil leakage phenomenon at the time of the pressure drop and the temperature change, which have been described in the previous embodiments. When the air in the cavities 3006 and 3007 expands as shown in fig. 48, the amount of expansion of the air in the cavity 3006 is released through the passage of air through the cavity 3004. The amount of expansion in the cavity 3007 is released by ink flowing from the cavities 3006 and 3004. In this manner, the cavity 3004 becomes a buffer cavity. The ability of the compressed ink absorber in the cavity 3004 to hold ink can be determined by the amount of oil that leaks out of the cavity. In this case, all of the compressed ink absorbents in 3004 are subjected to ink absorption once, so that the above-described advantageous effects can be obtained. Because the buffer chamber (chamber 3004) can be reduced in size, the amount of ink that settles when the ink is transferred after it is filled during the manufacturing process can be reduced.

Example 15

Example 15 is described with reference to fig. 49. The basic structure of the recording head is the same as that shown in FIG. 1. The inside of the replaceable ink cartridge 3001 is divided into 4 chambers a, h, c, d, and an ink absorber 3002 communicating with each other at the bottom and having an adjusted bladder force is filled in a communicating portion between the chamber a and the other chambers as ink supply portions without a gap. The chamber d having the air passage 3003 is filled with a buffer absorbent to prevent ink leakage. This constitutes such a mixing type ink tray.

In the state of fig. 49, about half of the ink in the cavity 3007 has been consumed. (in the initial state, the chambers 3004, 3006 and 3007 are filled with a sufficient amount of ink). When the ink is further consumed, as shown in fig. 50, as the ink in the cavity 3007 is depleted, the ink provided by the cavity 3006 will be consumed, the ink will continue to be consumed after the state shown in fig. 50, and when the ink in the cavity 3006 is depleted, the ink absorber in the cavity 3004 will begin to provide ink, and when the ink in the cavity 3004 is also depleted, the ink tank will be replaced.

FIG. 51 shows the ink supply and ink pressure reduction principle of this example 15. The ink 3201 in the ink chamber on the left side of fig. 51 has been exhausted, and the pressure in the chamber coincides with the atmospheric pressure due to communication between the air passage and the chamber. Ink is supplied to the recording head through the communication portion between the chambers, while the ink 3201 is supplied from the chamber communicating with the chamber having the atmospheric pressure, which supplies the ink absorber 3201 having a high sac force by compression through the chamber. The pressure drop of the ink chamber corresponds to the oil consumption. Thereafter, the air breaks the compressed ink absorber meniscus between the chambers into the chamber where the pressure drop is created by the ink flowing out. The internal pressure of the ink supply portion is maintained at a predetermined level by the bladder force of the compressed absorbent between the chambers.

FIG. 52 shows the change in the internal pressure of the ink supply portion of the replaceable ink tank of example 15, which is caused by the consumption of ink. The internal pressure is generated due to the tube force of the buffer absorbent or the ink absorbent, but the internal pressure is generated by the entire tube force of the compressed ink absorbent (compressed portion) on the passage between the chambers 3008 and 3007 according to the supply of the oil, so that when the ink is supplied from the chamber 3007, the stable ink pressure can be maintained as described above. When the ink is further consumed, the cavity 3006 starts to be supplied with ink. At the start of ink supply, the internal pressure of the ink supply portion slightly varies. This phenomenon is believed to be related to the measurement of internal pressure provided with the ink and to the occurrence of transient pressure drop conditions in the chambers 3007 and 3006. But it has been confirmed that such a change does not cause a significant problem for the function, such as the operation of the recording head.

When the ink in the chamber 3006 is stably consumed, the internal pressure is also stable. When the ink in the cavity 306 is depleted, the cavity 3004 begins to supply ink. During the ink stable supply shown in fig. 52, the recording operation was not adversely affected.

Fig. 53 shows the function of the buffer absorbing substance 3203. Due to the change in atmospheric pressure and the rise in temperature, the air in the chamber 3007 expands, and the ink flowing out of the chamber 3007 increases. In this embodiment, too much ink flowing into the cavity 3008 is retained by the buffer absorbent. The ability of the buffer absorber 3300 to retain ink at 0.7 atmospheres is fixed to 30% of the maximum ink leakage from the cavity 3007. When the atmospheric pressure returns to the level before the pressure drop, the ink leaking into the cavity 3008 and remaining in the buffer catch 3203 returns to the cavity 3007. This phenomenon also occurs when the temperature of the ink tank changes. But at temperature changes, even if the temperature rises to 50 deg., the leakage caused by temperature changes is smaller than the leakage caused by pressure drops.

In this case, the buffer absorbent is designed for maximum leakage. However, during the pressure drop test, a problem was found in that ink was leaked from some ink tanks, and therefore, the nature of the leakage prevention measure was performed depending on the individual tank. It has been found that this occurs due to a co-whine between the ink and the buffer absorbent of the chamber 3008.

In example 15, the buffer absorbent 3203 was subjected to ink absorption immediately before use. It has been confirmed that when the temperature rise or the pressure drop causes the air in the cavity 3007 to expand to cause the ink to be discharged into the cavity 3008, the buffer absorbent in the cavity 3008 absorbs the inflowing ink, and thus no leakage occurs.

As described above, since the chamber 3008 is an ink buffer chamber, it is preferable that no ink be injected at the start of use. Thus, in this embodiment, the chambers 3004, 3006, and 3007 are filled with a limited amount of ink, and the chamber 3008 is also filled with a limited amount of ink, after which the ink in 3008 is removed to ensure its cushioning capacity.

The ink tank constituted in this manner was loaded on an ink jet recording apparatus, and then subjected to a pressure drop test. The results confirmed that there was no leakage, the print quality was good and stable.

As described above with respect to examples 14 and 15, a can tray is mounted thereon, the tray including an ink supply chamber containing an ink absorbent having an adjusted bladder force and one or more ink chambers for containing ink and communicating with the ink supply chamber. The absorbent in the chamber is wetted with the ink, so that the ink leakage phenomenon does not occur even if the use environment of the recording apparatus changes, regardless of whether the apparatus is in a use or a stop state. Therefore, the use efficiency of the ink and the printing quality are high.

Example 16

In the ink pan of the above embodiment, when the supply chamber containing the ink aspirant becomes empty: in some cases, refilling is somewhat difficult.

FIG. 61 shows a condition to refill the ink into the tank, which provides that the ink in the chamber has been depleted. Even if the ink in the supply chamber (4004) runs out after the ink in the chamber 4006 has run out, a small amount of ink remains in the ink absorber. The ink forms a meniscus on each part of the absorbent. When ink is to be provided to the cavity 4006 that does not contain the ink absorber 4202, the meniscus in the absorber in the cavity 404 prevents dense injection of ink. While large bubbles remain as shown by a 611. When such an ink tank is attached to a recording head, the ink inflow is not sufficient due to the presence of the air bubbles, and is easily stopped.

In this case, the operator may not notice the emptying of the cavity 4006 because the ink is contained in the absorbent in the cavity 4004, and thus the recording operation may be performed with the oil in 4006 exhausted. Only when the recording work cannot be performed because the oil in the ink absorber in the cavity 4004 is exhausted, the operator knows that the ink in the cavities 4004 and 4006 is exhausted. At this time, even if the cavity 4006 is refilled, the entered ink does not come into contact with the ink contained in the absorbent in the cavity 4004, and therefore, the oil cannot be injected, and as a result, no air bubbles remain in the absorbent 4202 in the cavity 4004.

To solve this problem, an oil tank includes an ink supply chamber having an ink supply portion for supplying ink to a recording head, an air passage and an ink absorber disposed at the center, at least one chamber communicating with the ink supply chamber and containing ink, and means for detecting a decrease in the amount of remaining ink during a period in which a predetermined amount of ink is left in the ink chamber.

The following description is about the above-described device for detecting the amount of oil.

Fig. 54 shows an example of a control system according to the present invention, which includes a microcomputer controller having an a/D converter, a voltage converter 4300 and an alarm 4400. Reference numeral 4010 denotes a recording head. The warning device may be of the LED or similar type or of the sound type such as a buzzer or similar, or a combination of the above. A main scanning mechanism 4500 for scanningly moving the carrier HC includes a motor for feeding the recorded information. The reference symbol √ denotes a detection signal for the remaining oil amount of the oil tank. In this embodiment a constant current flows between the two electrodes in the cavity 4006, while the amount of ink remaining in the cavity 4006 is determined by the resistance between the two electrodes. In this case, the relationship between the remaining oil amount and the resistance is as shown in fig. 66.

As shown in fig. 55: when the oil level in the cavity 4006 is lower than the previous one of the two electrodes 410, the resistance between the two electrodes increases sharply and a corresponding voltage is generated. The voltage is AD converted either directly or through a voltage converter 4300 to the controller's a/D converter. When the measured value exceeds a predetermined level R + h, the operator is notified of the activation of the alarm 4400. And injecting ink. At this point, the host may be shut down or may be immediately shut down.

The consumption of ink ceases, so that a small amount of ink remains in chamber 4006, and therefore, ink can be re-injected into the absorbent in chamber 4004, so that the ink tank can be reused.

Fig. 56 shows a case where the internal pressure of the ink supply portion of the replaceable oil tank according to this embodiment changes according to the ink consumption amount. In the initial stage, its internal pressure (negative pressure) is generated by the bladder force of the compressed ink absorber in the cavity 4004, but the internal pressure generated by the bladder force gradually increases as the ink of the cavity 4004 is consumed, which change is generated in accordance with the change in the compression ratio of the compressed absorber 4202.

When the ink is further consumed, the consumption of the ink in the chamber 4004 is stably progressed, and the ink in the chamber 4006 starts to be consumed, air enters the chamber 4006 (in the manner described above), and thus a stable internal pressure is maintained. When the ink consumption in 4006 has reached a predetermined amount, the eighth volume sensor starts operating to perform a function of urging the priming and the printing operation to stop. This allows the ink in the chamber 4004 to be filled before it is consumed to a level not exceeding a predetermined level, and the filling operation is performed at a time of facilitating the filling.

Fig. 57 shows an example of a method of injecting ink. A tap hole on an ink supply portion 4005 of the chamber 4006 is opened, and ink is injected into the chamber 4006 through a tube 4052 and the like. After injection, plug 4051 is plugged. The method of re-implantation is not limited to this, and other methods may be used, and the position of the portion 4005 is not limited to the above. The ink tray can then be reused.

In the foregoing, the remaining amount of ink is detected by the resistance between the electrodes in the tank, but is not limited thereto, and may be detected by mechanical or photoconductive means.

In this embodiment, the oil tank is of a replaceable type, but the ink-jet recording head disk may have the recording head and the ink tank integrally thereon.

Example 17

Referring to the figures: 58, 59, and 60, example 17 will be described. The two lumens 4007 and 4008 are in fluid communication with the lumen 4006. In this example, the ink consumption order is: cavities 4006, 4007 and 4008. The ink chamber in this example was divided into 4 sections to prevent ink leakage due to the ambient pressure drop and temperature rise described in example 16. For example: when the air in the chambers 4006 and 4007 expands in the state shown in fig. 58, the amount of expansion in the chamber 4006 is released through the air passage and the chamber 4004. As shown in fig. 59, the amount of swelling in the cavity 4007 is released as the ink flows into the cavities 4006 and 4004. The ink chamber 4004 is then given the function of a buffer chamber. Therefore, the ink retention capacity of the compressed ink absorber 4002 in the cavity 4004 can be determined in consideration of ink leakage from one cavity.

In this example, ink is sequentially consumed from chambers 4006 and 4007. The ink consumption wheel then goes to the last chamber 4008, consuming the ink in chamber 4004 until terminated. To measure the amount of ink remaining in the chamber 4008, a telegram 4100 (shown in fig. 60) is charged in the chamber 4008. The cavity 4006 has an injection hole. In this example, the remaining ink was measured only in the cavity 4008. Thus, the chambers 4006 and 4007 can be filled with ink. If the electrodes are disposed at a considerable height as in example 16, the amount of ink remaining in the chamber without the absorbent can be reduced to effectively utilize the space when the electrodes detect the threshold.

In this embodiment, similar to embodiment 16, the absorbent-containing chamber 4004 can be refilled when there is insufficient oil in it.

Example 18

Fig. 62 shows example 18 in which the tank wall is made of a transparent or translucent material so that the amount of ink remaining is optically visible. In this example a reflective lens, such as a lens, is placed on the wall of the cavity 4006, one comprising: the light sensitive elements of one light directing element 4043 and one light receiving element 4044 are arranged outside the tank. The light emitting element 4043 and the receiving element 4044 can be positioned on a shelf or main body location with a recovery system.

In fig. 62, 4043 emits light at a predetermined angle, and the light-receiving member 4044 receives light through the mirror plate. For example, the light emitting member 4043 is an LED element, and the receiving member 4044 is a phototransistor or the like. In fig. 62, (a) is a full ink state in which light from 4043 is blocked by oil in the cavity 4006, and thus 4044 receives no light, and the output of the probe is small. If the oil is consumed to the state (b) in fig. 62, the output of the detecting member is high due to no blocking of light by the ink, and when the light energy received by 4044 (the output of the detecting member) exceeds a predetermined limit amount, a warning signal of the oil replenishment is generated.

Figure 63 shows an alternative embodiment in which the light emitting and receiving members are located on opposite sides of the tank. Fig. 63(a) is a plan view, and fig. 63(b) is a front sectional view. In this example, the material from which the cavity 4006 is made is also transparent or translucent. Therefore, a reflecting lens is not needed, and the detection effect is good because the light is directly received.

In the foregoing, description has been made with respect to a single oil tank, but the present invention is also applicable to a color ink jet recording apparatus having a plurality of recording heads for jetting black, cyan, magenta and yellow. The present invention is also applicable to ejecting different colors using one recording head.

Different limits may be used for different colors, and filter paper may be used to select a predetermined wavelength for different ink colors, so that the remaining ink may be detected by the optical conductivity of the ink.

The tank is replaceable, however, it is in a form having an integral recording head and tank, spray head disk.

Example 19

FIG. 64 shows example 19, in which the ink chamber of example 16 is divided into two parts, one of which (4007) is replaceable. Fig. 64 (a) shows a state where the remaining ink amount detecting member is activated, and a new chamber 4007 filled with ink can be replaced instead of the consumed ink chamber 4007. Fig. 64(b) shows such a replacement state. Fig. 64(c) shows that the replacement is completed. At this point, the valve plug 4052 at the bottom of the oil chamber is pushed open by the 4053 at the top of the chamber 4006, allowing ink to fill the chamber 4006. This has eliminated the need for tubing or injectors and has not dirtied the operator's fingers. Thus, the cavity 4004 and the cavity 4006 can be communicated with each other only by replacing one component, and therefore, the communication is economical.

In example 19, the ink remaining amount detecting member is not limited to the form of the inter-electrode resistance, and it may be of the kind described in example 18 or other kinds. A further method of detecting whether there is continuous flow of ink between the cavity 4004 and the cavity 4006 may be considered. One configuration of this method is to arrange two electrodes 4100 on both sides of the two-chamber channel, respectively.

In this embodiment, the recording head and the ink are separable. The recording head may be integrated with an ink tank having the chambers 4004 and 4006.

As described above for examples 16 to 19, the oil tank having a portion for supplying ink to the recording head and an air passage includes an ink supply chamber containing an ink absorbent, at least one chamber for containing ink communicating therewith, and a detecting member in the chamber for containing ink; the ink amount is measured and the result of the detection is notified to the operator, so that the recording operation can be stopped and the oil filling operation can be performed.

The inventors investigated the inks suitable for use in the foregoing examples of the present invention, and the most suitable inks exhibited stability against ink vibration in the air-liquid exchange portion thereof, and stability against changes in environmental conditions.

Suitable inks for use in the foregoing example tanks will now be described.

The basic components of the ink at least comprise water, pigment and organic solvent dissolved in the water. Organic solvents are low-volatility and low-viscosity substances with high water solubility. The following are examples of such solvents. Amides such as dimethylformamide and dimethylacetamide, ketones such as acetone; ethers such as dioxane and tetrahydrofuran: polydifermentations such as polyethylene glycol and polypropylene glycol; alkylene ethylene glycols such as ethylene glycol, propylene glycol, butylene glycol, triethylene glycol, thiodiglycol, hexylene glycol and diethylene glycol: lower alkyl ethers of polyhydric alcohols such as ethylene glycol methyl ether, diethylene glycol monomethyl ether and triethylene glycol monomethyl ether; monohydric alcohols such as ethanol and isopropanol; further, glycerin, 1, 2, 6-hexanethiol, N-methyl-2-pyrrolidone, 1, 3-dimethyl-2-imidazolidinone, triethanolamine, sulfolane, dimethylsulfoxide, and the like are also given. The water-soluble organic solvent component is not particularly limited. But it is 1-80% by weight. The colorant used in the present invention may be a pigment or a dye, and the dye may be an acid dye dissolved in water, a toner, a basic dye, a reactive dye or the like. The dye component is not limited, but is preferably 1 to 20% by weight based on the ink.

Surfactants are used to adjust the liquid level tension. Examples of surfactants are: anionic activators such as fatty acid salts, high-ethanol sulfuric acid ester salts, alkylbenzene sulfonates, and high-ethanol phosphorus ester salts; cationic active agents such as aliphatic amine salts and quaternary amine salts; anionic surfactants such as high-ethanol ethylene oxide adducts, alkylphenol ethylene oxide adducts, aliphatic ethylene oxide adducts, high-ethanol fatty acid ester ethylene oxide adducts, high-alkylamine ethylene oxide adducts, fatty acid amide ethylene oxide adducts, polypropylene glycol ethylene oxide adducts, high-ethanol fatty acid esters of polyhydric alcohol and alkanolamine fatty acid amides, and amphoteric surfactants of amino acids and betaine. The surfactant is not particularly limited, but preferably used anionic surfactants are high-ethanol ethylene oxide adducts, alkylphenol ethylene oxide adducts, ethylene oxide-propylene oxide copolymers, acetylene ethylene glycol ethylene oxide adducts. In addition, the mole number of the added ethylene oxide particularly in the ethylene oxide adduct should be in the range of 4 to 20. The amount of the surface active additive to be added is not particularly limited, but preferably 0.01 to 10% by weight of the total surface tension can be controlled by the above-mentioned water-soluble organic solvent.

In addition to the above-mentioned components, the starting liquid may contain a viscosity modifier, a pH adjuster, a mildewproofing agent or an antioxidant, as required.

The viscosity of the ink is 1-20cP and the surface tension should be 25-50 dyne/cm. If the ink surface tension is within this range, the liquid surface of the recording head will not break when the machine is not in use, and the ink will not flow out of the recording head orifice.

The amount of ink contained in the ink tray may be appropriately determined as the volume inside thereof so that the ink can be filled up to the limit in order to maintain the degree of vacuum at the moment when the tray is detached. However, the amount of ink in the vacuum product may be less than its holdout capability, so the ink holdout of the vacuum product is the amount that may be held.

Inks according to the examples of the invention and comparative examples are described below.

Mixing water and water-soluble organic solvent, adding dye, stirring for 4 hr, adding surfactant, and sieving to remove foreign matters. The ink thus prepared was poured into the ink pan in fig. 11, and then the operation of the apparatus shown in fig. 12 was performed.

The following is a comparison of ink properties and recorded print results.

Examples 1, 2, 3 and 4

Diethylene glycol 15% 10% 10% 10%

2 percent of cyclic ethanol

5 percent of glycerin

Thiodiglycol 5% to 5%

Surfron S-145 0.1％

(fluorinated surfactant)

ACETYLENOL EH 2％

(acetylene ethylene glycol-ethylene oxide)

Adduct)

Dye 2.5% 2.5% 0.2% 2.5%

Water balance

Surface tension 31(dyne/cm) 254040

In use, the inks of examples 1 to 4 were smoothly consumed, and the print quality was very satisfactory

Comparative example 1 comparative example 2

Diethylene glycol 15%

5 percent of glycerin

Thiodiglycol 5%

Surfron S-145 0.1％

(fluorinated surfactant)

ACETYLENOL EH

(acetylene ethylene glycol-Oxidation

Ethylene addition product)

Dye 2.5%

Balance of water

Surface tension 17.6(dy ne/cm) 57.4

When the ink of example 1 was used, the color was clear and a small amount of the ink was dripped from the recording head. Example 2 the ink was used, the colors diffused among each other, and a small amount of the ink dropped out of the recording head.

The yellow dye is acid yellow 23, cyan is acid blue 9, magenta is acid red 289, and the black dye is pure black 168.

The surface tension is measured by the Williams method at 25 ℃.

The following are typical surface potential sites of water-soluble organic solvents at 20 ℃ to 25 ℃:

ethanol (22dyne/cm (1dyne/cm ═ 1.02 × 10)^-3g/cm), isopropanol (22dyne/cm), cycloethanol (34dyne/cm), glycerol (63dyne/cm), diethylene glycol (49dyne/cm), diethylene glycol monomethyl ether (35dyne/cm), triethylene glycol (35dyne/cm), 2-pyrrolidone (47dyne/cm), N-methylpyrrolidone (41 dyne/cm).

The desired surface tension is obtained by mixing with water.

A method of controlling the surface tension of the ink using the surfactant will be described below.

For example, 1% sorbitan monolaurate is added to provide a surface tension of 28dyne/cm and mixed with water; at 35dyne/cm, 1% polyoxyethylene-sorbitan monolaurate is added: at 28dyne/cm, not less than 1% of ACETYLEN0L EH (acetylene ethylene glycol-ethylene oxide adduct) is required. If a lower tension is desired, 0.1% of surflons-145 (perfluoroalkyl-ethylene oxide adduct) (available from Sahi Glass Kabushiki Kaisha, Japan) may be added to obtain a tension of 17 dyne/cm. The surface tension can also be slightly varied with additional additives and can therefore be suitably adjusted by the person skilled in the art.

As described above, the ink buffer is designed in consideration of the maximum leakage ink amount. It has been found that the buffering effect is strongly dependent on the ink composition.

The following is a comparative example.

Comparative example 3

Dye 4 moiety

Glycerol, fraction 7.5

Thiodiglycol 7.5 part

Urea 7.5 part

73.5 portions of pure water

When ink is discharged from the cavity 3006 to the cavity 3004 (air in the cavity 3006 expands due to the pressure decrease or temperature increase shown in fig. 46), a problem arises in that ink is not absorbed by the absorbent but leaks out through a gap between the tank wall and the absorbent or through an air passage.

Inks containing surfactants are used. The advantage of this ink is that the fixing properties on copy, bond or other plain paper are very good, i.e. the printed colours are moderate and no mixing (bleeding or the like) occurs, even when different colours are printed out next to each other. Therefore, the entire coloring becomes possible. The following are examples of such compositions.

Component example 5

Dye 4 parts

7.5 parts of glycerin

7.5 parts of thiodiglycol

Acetylene ethylene glycol ethylene oxide 5 parts

Adduct (m + n ═ 10)

7.5 portions of urea

68.5 portions of pure water

When the above-described ink is used, when the ink is discharged into the chamber 2004 due to the expansion of the air in the chamber 2006, the ink is absorbed by the ink absorber in the chamber 2004, and the ink does not leak from the ink tray. The above-described air expansion is caused by a temperature rise or a pressure drop as shown in fig. 34.

As described above, the air-liquid phase boundary is maintained at a level where the static head and the chamber 2006 of the ejection portion of the recording head and the vacuum portion of the compression absorbing bag tube force are maintained when ink is supplied from the chamber 2006 to the chamber 2004. Assuming an average height of the gas-liquid phase boundary in chamber 2004, which is H, when the ink in chamber 2006 flows out due to changes in electrical pressure and temperature, the gas-liquid phase boundary in chamber 2004 may be expected to be maintained at a higher H value-in one example of this embodiment, the total height of the ink in chamber 2004 is 3cm, chambers 2004 and 2006 each have a capacity of 6cc, and in the initial phase, chamber 2006 is filled (6cc), while chamber 2004 (with compressed ink absorber 2003 therein, which is a polyurethane foam) contains 4cc of ink, the porosity of the absorber being not less than 95%. If it is assumed that the ink is completely contained in the pores of the absorbent, the chamber 2004 can hold 6cc of ink. Ink consumption begins first with chamber 2004 and, after a certain time, begins to consume ink in chamber 2006, while the air-liquid phase boundary in chamber 2004 is maintained at a level. At this level, the static head of the ejection portion of the recording head, the degree of vacuum of the chamber 2006, and the bag force compressing the ink absorber are in a balanced state. On average, the level (gas-liquid phase boundary) at this time was about 1.5 cm. If it is assumed that all of the absorbent pores contain ink, the volume of ink in chamber 2004 is approximately 3 cc. At this point the maximum pressure is reduced to 0.7 atmospheres so that approximately 1.8cc of ink occupying chamber 200630% can flow from chamber 2006. Thus, chamber 2004 absorbs and holds approximately 3cc +1.8cc (approximately 2.4cm ink level) of ink. When the maximum pressure is reduced to 0.5 atmospheres, about 50% of the 3cc ink in chamber 2006 can flow out of chamber 2006, and thus a volume of about 3cc +3cc (about 3cm high liquid level) of ink can be absorbed and held in chamber 2004. Thus, ink chamber 2004 has sufficient space to contain the volume of absorbent, both the volume of ink in its chamber and the volume of ink flowing from chamber 2006. It can be seen that the volume of chamber 2004 is determined to take into account the amount of flow from chamber 2006 into it.

The ink height H absorbed by the porous absorbent is generally compressed by the bladder force according to the following equation.

H-2 γ cos θ/ρ gr, where γ is the ink surface tension, θ is the contact angle of the ink and its absorber, ρ is the density of the ink, g is the strategy, and r is the average pore size of the absorber.

It should be understood that to increase the ink retention by increasing the height of H, one would consider increasing the surface tension of the ink, or decreasing the contact angle of the ink with its absorber (cos θ increases).

As for the increase in surface tension, comparative example 3 has a relatively high surface tension (50 dyne/cm)²). However, as described above, the ink is not properly absorbed by the absorbent. For a decrease in the angle θ, it means increasing the wettability of the ink to the absorbent. To accomplish this, a surfactant is used.

In the case of the ink of example 5, the surface tension thereof was small (30 dyne/cm)²) This is because the wettability between the ink and the absorbent is improved by adding the surfactant. To improve penetration, it is more effective to improve ink wetting than to increase surface tension.

To compare ink permeability, the compressed ink absorber (polyurethane foam) was immersed in the inks of examples 3 and 5, and then the absorption height was measured. The ink of example 3 was absorbed only a few millimeters high, while the ink of example 5 was absorbed up to 2 centimeters or more. It can be understood from this that the permeability of the ink is improved by the addition of the surfactant (example 5), and the ink can be sufficiently absorbed by the absorbent. Even if the ink in the ink chamber flows out excessively due to a pressure drop or a temperature rise, it is sufficiently absorbed.

The selected penetrants include anionic surfactants such as OT type aerosol, sodium dodecylbenzenesulfonate, sodium dodecylsulfate, high ethanol-ethylene oxide adduct (formula 1), amphoteric ethylene oxide adduct (formula 2), ethylene oxide-propylene oxide copolymer (formula 3) and acetylene ethylene glycol ethylene oxide adduct (formula 4).

Anionic surfactants have a strong tendency to foam, but have poor properties in terms of dye diffusion, color integrity and enamel-sulphur bloom, comparable to nonionic surfactants. The nonionic surfactants shown in the following formulation were used additionally.

4 chemical formulas

Where R is alkyl

Where R is alkyl

Where R is hydrogen or alkyl

In the formulae (formulations) 1 and 2, n may have a value of 6 to 14 and R may have 5 to 26 carbon atoms. In chemical formulas 3 and 4, m + n may be 6 to 14, and m and n are monomers, respectively.

Among the ethylene oxide nonionic surfactants, acetylene ethylene glycol ethylene oxide adducts can be used in consideration of the absorbability of the absorbent, the print quality on the recorded matter and the ejection work as a whole. The hydrophilicity and permeability can be controlled by improving the value of m + n of the added ethylene oxide. If the value is less than 6, the permeability is good and the water solubility is not good. If the value is too large, the hydrophilic evolution becomes too strong and the permeability becomes poor. If the value is larger than 14, the permeability is sufficient but the ejection quality becomes poor. Therefore, the value is preferably in the range of 6 to 14.

The nonionic surfactant may be present in an amount of 0.1 to 20% by weight, and if it is less than 0.1, the printing quality and the penetrability are not sufficiently good. If it exceeds 20%, the effect is not improved, but the cost is increased and the reliability is reduced.

One or more of the above surfactants may be used in combination.

The ink may contain a dye, a low volatile organic solvent such as a polyol to prevent clogging, or an organic solvent such as ethanol to improve the stability of foam generation and the fixation of the impression on the print.

The ink of the present embodiment constituted of a water-soluble organic solvent may include polyethylene glycol such as polyethylene glycol and polypropylene glycol; alkylene glycols having 2 to 6 carbon atoms, such as ethylene glycol, propylene glycol, butylene glycol, triethylene glycol, 1, 2, 6-ethanethiol, hexylene glycol, and diethylene glycol; lower alkyl ethers of polyhydric alcohols such as ethylene glycol methyl ether, diethylene glycol monomethyl (or ethyl) ether and triethylene glycol monomethyl (or ethyl) ether; alcohols such as methyl ethanol, ethyl ethanol, n-propyl ethanol, isopropyl ethanol, n-butyl ethanol, F-butyl ethanol, T-butyl ethanol, isobutyl ethanol, benzyl ethanol and cyclohexanol; amides such as dimethylformamide and dimethylacetamide; ketones and ketoalcohols such as acetone and diacetone alcohol; ethers such as tetrahydrofuran and dioxane; and nitrogen-containing rings such as N-methyl-2-pyrrolidone, 1, 3-dimethyl-2-imidazolidinone.

The addition of water-soluble organic solvents does not affect print quality and jetting reliability. Preferably, a polyhydric alcohol or an alkyl ether thereof is used. The content of the water is 1-3 wt%, and the pure water is 50-90 wt%.

Dyes suitable for use in the present invention include direct colorants, acid dyes, disperse dyes, vat dyes, or the like. The amount of dye depends on the ink composition and the characteristics required therefor, and the ejection amount of the recording head or the like. Typically, the amount of dye is from 0.5 to 15% by weight, and may be from 1 to 7% by weight.

By adding thiodiglycol or urea (or a derivative thereof), the ejection quality and clogging (solidification) prevention performance of the ink are significantly improved. This is considered to be an improvement in the coagulation phenomenon of the dye in the ink. The thiodiglycol or urea (or its derivative) may be added to the ink in an amount of 1-3 wt%, if necessary.

The main components of the ink of the present invention have been described above. Other additives may also be used in combination to achieve the objectives of the present invention. The additives may include viscosity modifiers such as polyvinyl alcohol, cellulose, and water-soluble resins; pH control agents such as diethanolamine, triethanolamine, and buffer solutions, bactericides, and the like. For the kind of ink having a form of electric charge used in jet recording, oil droplets thereof are charged at the time of use, so that some resistance adjusting agents such as lithium chloride, ammonium chloride and sodium chloride may be added.

The following description will discuss comparative examples

Comparative example 43 parts

5 parts of dye

Diethylene glycol 5 parts

Thiodiglycol 3 parts

84 parts of pure water

In this case, when the ink is excessively discharged from the oil chamber into the ink absorber chamber under a change in pressure decrease or temperature increase, there arises a problem that the ink leaks out through a gap between the tank wall and the absorber or through an air passage.

Then, the surfactant is added in the ink. Such inks have the advantage that the print is fixed very quickly, whether on copy paper, adhesive paper or other paper. It also has the advantage that even if different colours come into contact in the recorded print they do not produce an inappropriate colour overlap, whereby a uniform colouring can be carried out. The following are examples of such inks.

Comparative example 6

Dye 3 parts

5 parts of glycerin

Thiodiglycol 5 parts

3 portions of ethylene oxide-propylene oxide polymer

5 portions of urea

79 parts of pure water

When the present ink is used, it is absorbed by the ink absorber in the chamber, and even if a pressure drop or a temperature rise causes a large amount of ink to flow into the chamber having the absorber, the absorption is sufficient.

As described above, the ink pan of the present invention comprises an ink supply chamber having an ink absorber for adjusting the force of a bladder tube, and one or more ink chambers, and is characterized in that the ink contains a nonionic surfactant so that the ink does not leak when a recording operation is performed or stopped when external conditions are changed, thereby improving the ink use efficiency.

The above examples 1 to 13 all have respective advantages, and if used in combination, the advantages are greater. In addition, the combination of the processes of examples 14 and 15 and the combination of the structures of examples 16 to 19, in addition to the above-mentioned ink, the present invention is more effective.

The present invention is applicable to any ink ejection device, such as those that use electromechanical transducers, such as piezoelectric elements. But is particularly suitable for such recording apparatuses, i.e., apparatuses that eject or discharge ink by causing a change in the state of ink with thermal energy using an electrothermal transducer, a laser beam, or the like. This is because recording with high density and high resolution performance has been possible.

The typical construction and operation can be the same as disclosed in us 4723129 and 4740796, which applies to a so-called commanded recording system and a continuous recording system. However, it is particularly suitable for use in an on-demand system because its operating principle is: at least one drive signal is transmitted to an electrothermal transducer, the transducer being disposed in the ink receiving plate or channel, the drive signal causing a rapid temperature rise in excess of a nucleation boiling point deviation, thereby providing thermal energy through the electrothermal transducer to cause film boiling at a heated location on the recording head, whereby each signal forms a bubble in the ink.

At least one drop of ink passes through the ejection port by generation, development, and contraction of the bubble. Since the development and shrinkage of the bubble can be instantaneously performed, the ejection reaction of the ink is fast. The drive signal is in the form of pulses, which may be in the form disclosed in us 4463359 and 4345262. Further, the temperature increase rate of the heating surface may be referred to the technical contents disclosed in U.S. patent 4313124.

The structure of the recording head may also be of the form as disclosed in us patents 4558333 and 4459600. The heating part is arranged on a bending part, and the bending part is also provided with the combination structure of the jet orifice, the liquid channel and the electric heating conductor. Further, the present invention is also applicable to Japanese patent application No. 123670/1984 in which a common slit is used as the ejection port of the plurality of electrothermal transducers. The present invention is also applicable to the structure disclosed in japanese patent application 138461/1984, in which one opening that absorbs thermal energy pressure waves corresponds to the ejection section. This is because the present invention can perform a recording operation efficiently and surely without being limited by the kind of recording head.

The present invention can be effectively applied to a recording head of the so-called full-line type having a length corresponding to the maximum recording width, which may include a single recording head and a plurality of recording heads in combination covering the maximum recording width.

Further, the present invention is also applicable to a variety of series of recording heads which are fixed to a main body; a recording head of the kind in which a circuit integrated block is replaceable, the recording head being electrically connected to a host device and being capable of ejecting ink when the recording head is mounted on the host device; or a disc-like recording head having only unit ink tanks.

Recovery means and auxiliary means for operation are still employed because they can further stabilize the effects of the present invention. Specific means include sealing of the recording head, cleaning, pressurizing or absorbing, a preheater which may be an electrical heat conductor, an added heater or a combination of the above. Further, the means for performing the preliminary ejection can stabilize the recording operation.

As for the variation of the mountable recording head, it may be one corresponding to one unit-independent color, or may be each corresponding to a plurality of inks having different colors or densities. The present invention is effectively applicable to a recording head device of at least one of a single color type of mainly black, a multi-color type of inks having different colors, or a full color type using a mixed color, which may be a recording head formed integrally, or a recording head unit in which a plurality of recording heads are combined.

In the foregoing examples, the inks were all liquids. But may also be a solid ink that cures at below room temperature and liquefies at room temperature. Since the ink is controlled to be between 30 ℃ and 70 ℃ in a usual recording apparatus to ensure viscosity and ejection, an ink in an all liquid state in this range can be used. Other types of inks may also be used with the present invention. One is that this heat, which raises its temperature, is absorbed when its temperature tends to rise due to heat conduction, and is transferred to change the solid ink into liquid ink. The additional ink is cured when not in use, preventing evaporation. In all of the above cases, the thermal energy generated by the recording signal is used to liquefy the ink so that ejection can be performed. Another ink may be one which is cured while it reaches the recording material. The present invention is also applicable to an ink substance which is liquefied by heat and which is retained in the holes or pores of the porous sheet body in a liquid or solid form, as disclosed in japanese patent application laid-open nos. 56847/1979 and 71260/1985. The sheet body retaining the solid or liquid ink faces the electric heat conductor. The most effective heating means for the ink described above is the film boiling system.

The ink jet recording apparatus can be used as a terminal apparatus for an information processing apparatus, such as a computer or the like; a copying device incorporating a screen reader or the like; or a facsimile machine having the information selecting and receiving function.

While the invention has been fully described, it is not to be restricted by the foregoing disclosure, and it is intended that this application cover modifications within the scope of the appended claims and their equivalents.

Claims (17)

1. A replaceable ink container for an ink jet printer having a mount for receiving the replaceable ink container and supporting the ink container during ink jet printing, the replaceable ink container comprising:

a can formed from front, back, top, bottom and side walls;

the canister is internally divided into a first chamber and a second chamber;

said first chamber and said second chamber having a common dividing wall extending vertically downwardly toward said bottom wall to provide an opening formed by said dividing wall between said first chamber and said second chamber proximate said bottom wall;

the first cavity is substantially sealed from ambient air except through the opening;

said second chamber having a vent for allowing ambient air to enter said second chamber;

the first chamber contains a liquid ink reservoir;

said second chamber having an ink supply outlet;

the second cavity contains a spongy material for holding ink;

at least one slot in the second chamber side of the dividing wall extending from the opening and terminating at a point partially above the dividing wall to form an air flow path from the second chamber to the first chamber;

said sponge-like material being located within said second chamber to allow air flow from said vent to said gutter to allow air to be introduced into said first chamber when the level of ink held within said sponge-like material is close to said point where said gutter portion terminates partially above said dividing wall, liquid ink flowing through said opening into said ink supply outlet; and the canister is removably mountable in an inkjet printer mount with the bottom wall down.

2. The replaceable ink cartridge of claim 1 wherein the slot is formed by a projection extending along the surface of the divider wall.

3. A replaceable ink cartridge according to claim 1 wherein the slot is formed by a channel in the surface of the dividing wall.

4. A replaceable ink cartridge according to claim 1, wherein the groove is formed in a recessed portion of the partition wall.

5. The replaceable ink cartridge of claim 1 wherein the slot introduces ambient air to reduce the negative pressure in the first chamber.

6. A replaceable ink cartridge according to claim 1 or 5 wherein the sponge material is an ink absorbing material.

7. The replaceable ink cartridge of claim 6 wherein the sponge material is a foam material.

8. The replaceable ink container of claim 7 wherein the foam is compressed within the second chamber to create a negative pressure that varies from the opening to the ink supply outlet.

9. The replaceable ink cartridge of claim 8 wherein the canister is contained in an air-tight sealed package for shipping.

10. The replaceable ink cartridge of claim 6 wherein the sponge material has a predetermined pore size to control the transfer of the liquid ink from the ink reservoir to the ink supply outlet.

11. The replaceable ink cartridge of claim 1 wherein the liquid ink includes water, a coloring material, and a water soluble organic solvent, and has a surface tension of 20dyne/cm to 55 dyne/cm.

12. The replaceable cartridge of claim 11 wherein the liquid ink includes at least one ionic surfactant.

13. The replaceable ink container of claim 1 wherein the canister is a material that is transparent to the interior thereof.

14. A replaceable ink cartridge according to claim 1 wherein the negative pressure producing material is a sponge that is not thermally compressed but is compressed into the first chamber.

15. The replaceable ink cartridge of claim 1 wherein the negative pressure producing material is a heat compressed sponge.

16. The replaceable ink cartridge of claim 1 wherein a path connecting the vent and the point extends across the negative pressure producing material.

17. A replaceable ink cartridge according to claim 1 wherein a plurality of such air introduction passages are provided.