JP2010089477A - Liquid supply system and inkjet printer using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid supply system which can rapidly level a density difference of a precipitable substance, in a system for intermittently supplying a liquid including the precipitable substance such as a pigment through a capillary, for example, as an embodiment, to provide a liquid supply system which shortens a time for a pigment precipitated after a pause period of an inkjet printer, to be uniformly mixed and then to reach an ordinary pigment density. <P>SOLUTION: The liquid supply system supplies a liquid including a precipitable substance 3a through a capillary 3, and is provided with a region having: a larger width than the inner diameter of the capillary at least in part of capillary; and a difference in height in a direction to supply a liquid. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a liquid supply system capable of leveling a concentration difference of the sedimentary substance in a short time in a liquid supply system that supplies a liquid (ink) containing a sedimentary substance such as a pigment through a thin tube, and the same The present invention relates to an ink jet printer using the printer.

FIG. 4 shows an ink jet printing apparatus equipped with a conventional ink supply mechanism, and the following configuration is known as a print mechanism of the ink jet printer (arrangement relationship between an ink tank, a print head, and an ink supply tube). (See Patent Document 1)
In FIG. 4, an ink jet printing apparatus 1 is provided inside a printing mechanism and provided on a carriage 11 on which a printing head (not shown) is mounted, and is provided outside a printing mechanism, which is a pressure adjusting unit 12 made of a diaphragm. An ink tank 15 for storing ink to be supplied to a print head mounted on the carriage 11 via the pressure adjustment unit 13, the pressure adjustment unit 13, the ink supply tube 14, and the pressure adjustment unit 12, and the print head and pressure adjustment unit 12 are mounted. A carriage drive belt 17 for driving the carriage 11 along the carriage guide 16, a carriage drive motor 18 for driving the carriage drive belt 17, and a print sheet conveyance guide portion 19 for conveying the print sheet to the print position. It is configured.

  The carriage drive motor 18 is driven by a control signal from a host device (not shown) and the carriage drive belt 17 is driven, so that the carriage 11 on which the print head and the pressure adjusting unit 12 are mounted follows the carriage guide 16. Printing is performed on the printing paper conveyed from the printing paper conveyance guide unit 19 by reciprocating to a predetermined printing position.

At that time, the ink supply tube 14 connected to the pressure adjustment unit 12 mounted on the carriage 11 is flexibly bent along with the moving carriage 11. There is a difference in the size of the pressure adjusting units 12 and 13, the pressure adjusting unit 12 provided on the carriage 11 is light and small, and the pressure adjusting unit 13 is large and maximizes the effect of suppressing pressure fluctuation. It has a structure that can be taken.
JP2001-80088

In recent years, in outdoor printing, it has become the mainstream to use pigment inks that are more durable than dye inks. For example, in the conventional printing apparatus (ink jet printer) shown in FIG. 4, a supply tube (capillary tube) is used to supply ink from an ink tank containing ink containing a color material such as pigment to the print head. Although both are connected via, the supply tube was normally arrange | positioned in the state extended flatly so that the space | interval of both might be tied as short as possible.
Inkjet printers may not be used continuously but may be used intermittently after several days or more of rest periods, but if there is a gap, they are used for inkjet printers. There is a problem that pigment ink (for example, white ink) settles, causing nonuniform printing density, ejection failure, and nozzle clogging. In particular, in the case of an inorganic pigment such as titanium oxide used as a pigment for white ink, there is a problem that the ink tends to settle during a period when the ink is not flowing (rest period).

Next, a problem when a pigment (in this example, titanium oxide) settles in a thin tube (ink supply tube) will be described with reference to FIG.
FIG. 1 schematically shows a state where an ink tank (cassette) 1 and an ink head 2 are connected by a thin tube (ink supply tube) 3 arranged horizontally.

As shown in FIG. 1, when the ink jet printer is in a rest state for a long period, the pigment contained in the ink is settled as shown in FIG.
In the upper part of the pigment 3a, the ink 3b in a thin state of the pigment is in a supernatant state.

Here, when the ink jet printer is put into an operating state from a long period of inactivity, and the ink is discharged (discharged) from the ink head 2, the ink 3b in a state where the pigment concentration in the upper portion of the thin tube 3 is low for a while. Is mainly discharged (discharged).
Thereafter, as the ink 3b having a low pigment concentration is discharged and the agitated ink is supplied from the ink tank, the portion in contact with the settled pigment is gradually agitated. It takes a lot of time to mix and reach the desired pigment concentration.
If this is seen from the print result of the medium, since the print with a light density that is not the intended pigment density continues for a predetermined time, it is not preferable as the print state, and this period (the ink state that achieves the desired pigment density) During this period, the ink must be shot and discharged.

  As a countermeasure against the sedimentation of the pigment ink used in the ink jet printer, there is a countermeasure for mixing the settled pigment by vibrating the ink tank containing the ink or stirring the inside of the tank. Until now, no effective measures have been taken against the sedimentation of the pigment in the narrow tube (ink supply tube) between the tank and the head.

An object (object) of the present invention is that a concentration difference of the sedimentary substance in a liquid supply system that intermittently supplies a liquid containing a sedimentary substance such as a pigment via a thin tube can be leveled in a short time. The present invention relates to a liquid supply system.
For example, a specific example is to realize a liquid supply system capable of shortening the time until the settled pigment is uniformly mixed and reaches a normal pigment concentration after the rest period of the inkjet printer.

In order to solve the above problems, a liquid supply system of the present invention is a liquid supply system that supplies a liquid containing a sedimentary substance via a thin tube,
A region (D) having a height difference in the direction of supplying the liquid having a width (H) larger than the inner diameter (r) of the capillary is provided in at least a part of the capillary.
In the present invention, the “region portion having a height difference” means that the sedimented material 3a or 7a settles in the region portion as described later in FIG. 2 and FIG. It means the shape of a narrow tube closed by.

Further, the region portion is formed in a spiral or circular arrangement.
Further, the region portion has an arrangement configuration including a curved portion.
The bending portion is wavy.
The wave shape includes a sine wave (monotone wave) formed by a single frequency component and a composite wave formed by a plurality of frequency components.
The curved portion or the wavy slope is characterized in that the descending direction is steeper than the ascending direction of the liquid.
In addition, the inclination along the flow direction of the liquid is the upward direction (downward direction) means the inclination of the capillary tube when the liquid goes up or down when passing through the curved part or the wavy part. It gradually rises at the wavy part and falls abruptly.
In addition, the thin tubes have an arrangement configuration in which a horizontal portion does not exist.
Moreover, the said area | region part is comprised by two or more, It is characterized by the above-mentioned.

  An inkjet printer comprising the liquid supply system, wherein the narrow tube is an ink supply tube that connects an ink tank and a head in an inkjet printer that uses pigment ink as the sedimentary substance. .

In addition, when the ink jet printer is installed, the ink tank and the head are arranged substantially horizontally, and the ink supply pipe connects the both substantially horizontally.
In addition, when the ink jet printer is installed, the ink tank and the head are arranged with a height difference in the vertical direction, and the ink supply pipe connects the two vertically or obliquely.
The ink supply pipe is made of a flexible material, and is fixed so as to be able to vibrate with the movement of the head.
The liquid pigment may contain titanium oxide.

In addition, the liquid (ink) containing a sedimentation substance in the present invention indicates a liquid (ink) having a large specific gravity difference between the solvent and the pigment as compared with a general pigment ink. Specifically, the specific gravity of carbon black or organic pigment, which is a general pigment, is about 1 to 1.3 with respect to the dispersion solvent (water has a specific gravity of 1 and organic solvent of 1 or less). 3.7 to 4.2, and indicates a liquid (ink) having a specific gravity difference of 1 or more between the solvent and the pigment.
In the present invention, not only titanium oxide but also white pigments such as oxides such as zinc, lead, barium, titanium and antimony, sulfates and carbonates, and metallic pigments such as aluminum and aluminum alloys (specially as an example) Kai 2008-174712) can also be used.
In addition, although the ink of the present application has been described using water-based ink as an example, it can also be applied to ultraviolet curable ink. Further, the medium may be water, a solvent, or a polymerizable monomer as long as it contains a sedimenting substance.

  When the liquid (ink) of the present invention contains the white pigment of the present invention, the content (solid content) of the particles of the present invention is preferably 5 to 20% by mass with respect to the total mass of the ink composition. More preferably, it is 8-15 mass%. When the content (solid content) of the white particles exceeds 20% by mass, reliability such as clogging of the ink jet recording head may be impaired. On the other hand, when it is less than 5% by mass, the whiteness tends to be insufficient. In order to improve dispersibility, the particle size of the colorant is preferably 2.0 μm or less, more preferably 0.2 μm or less.

The ink composition of the present invention contains a resin for fixing the pigment of the present invention. Examples of such resins include acrylic resins (for example, Almatex (manufactured by Mitsui Chemicals)) and urethane resins (for example, WBR-022U (manufactured by Taisei Fine Chemical Co., Ltd.)).
The content of these fixing resins is preferably 0.5 to 10% by mass and more preferably 0.5 to 3.0% by mass with respect to the total mass of the ink composition.

  The ink composition of the present invention preferably contains at least one selected from alkanediols and glycol ethers. Alkanediols and glycol ethers can enhance the wettability of a recording surface such as a recording medium and improve the ink permeability.

  Examples of the alkanediol include 1,2-butanediol, 1,2-pentanediol, 1,2-hexanediol, 1,2-heptanediol, 1,2-octanediol, 2-Alkanediol is preferred. Of these, 1,2-hexanediol, 1,2-heptanediol, and 1,2-octanediol having 6 to 8 carbon atoms are more preferred because of their particularly high permeability to recording media.

  The glycol ethers include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, triethylene glycol. Mention may be made of lower alkyl ethers of polyhydric alcohols such as monomethyl ether, triethylene glycol monobutyl ether and tripropylene glycol monomethyl ether. Among these, when triethylene glycol monobutyl ether is used, good recording quality can be obtained.

  The content of at least one selected from these alkanediols and glycol ethers is preferably 1 to 20% by mass, more preferably 1 to 10% by mass, based on the total mass of the ink composition.

  The ink composition of the present invention preferably contains an acetylene glycol surfactant or a polysiloxane surfactant. Acetylene glycol surfactants or polysiloxane surfactants can increase the wettability of a recording surface such as a recording medium to increase the ink permeability.

  Examples of the acetylene glycol surfactant include 2,4,7,9-tetramethyl-5-decyne-4,7-diol, 3,6-dimethyl-4-octyne-3,6-diol, 3, 5-dimethyl-1-hexyn-3-ol, 2,4-dimethyl-5-hexyn-3-ol and the like can be mentioned. Moreover, a commercial item can also be utilized for acetylene glycol type-surfactant, for example, Orphine E1010, STG, Y (above, Nissin Chemical Co., Ltd.), Surfinol 104, 82, 465, 485, TG (above , Air Products and Chemicals Inc.).

  Commercially available products can be used as the polysiloxane surfactant, and examples thereof include BYK-347, BYK-348 (manufactured by BYK Japan).

  Furthermore, the ink composition of the present invention can also contain other surfactants such as an anionic surfactant, a nonionic surfactant, and an amphoteric surfactant.

  The content of the surfactant is preferably 0.01 to 5% by mass and more preferably 0.1 to 0.5% by mass with respect to the total mass of the ink composition.

  The ink composition of the present invention preferably contains a polyhydric alcohol. When the ink composition of the present invention is applied to an ink jet recording apparatus, the polyhydric alcohol can suppress ink drying and prevent ink clogging in the ink jet recording head portion.

  Examples of the polyhydric alcohol include ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, polypropylene glycol, propylene glycol, butylene glycol, 1,2,6-hexanetriol, thioglycol, hexylene glycol, glycerin, and trimethylolethane. And trimethylolpropane.

  The content of the polyhydric alcohol is preferably 0.1 to 3.0% by mass, more preferably 0.5 to 20% by mass with respect to the total mass of the ink composition.

  The ink composition of the present invention contains water as a solvent. It is preferable to use pure water or ultrapure water such as ion exchange water, ultrafiltered water, reverse osmosis water, or distilled water. In particular, water obtained by sterilizing these waters by ultraviolet irradiation or addition of hydrogen peroxide is preferable because generation of mold and bacteria can be suppressed over a long period of time.

  In addition, the ink composition of the present invention may contain a fixing agent such as a water-soluble rosin, an antifungal agent / preservative such as sodium benzoate, an antioxidant / ultraviolet absorber such as allophanates, a chelating agent, if necessary. Additives such as oxygen absorbers can be included. These additives can be used alone or in combination of two or more.

ADVANTAGE OF THE INVENTION According to this invention, the liquid supply system which can equalize the density | concentration difference of the said sedimentation substance in the liquid supply system which intermittently supplies the liquid containing a sedimentation substance via a thin tube can be implement | achieved. .
In addition, by applying to the ink pigment of an ink jet printer as a sedimentary substance, it is possible to shorten the time until the pigment that has settled after a long rest period is uniformly mixed and reaches a normal pigment concentration, which is useless. Ink consumption can be reduced.

A first embodiment of the present invention will be described below.
Using FIG. 2, the pigment concentration leveling that can shorten the time until all of the precipitated pigment melts into the ink and reaches the normal pigment concentration after the rest period of the inkjet printer, which is the subject of the present invention, is realized. The principle will be described.

FIG. 2 has the same configuration as the state in which the ink tank (cassette) 1 and the head 2 in FIG. 1 are connected by a thin tube 3 disposed horizontally, and is different from FIG. The thin tubes are arranged horizontally, whereas the thin tubes are curved three times in a vertical direction (relative to the ground) (not necessarily three times).
The capillary shown in FIG. 2 has a diameter of 2 mm, and the diameter of the spiral (circular) is preferably 5 cm or less, preferably larger than the diameter of the capillary.

In FIG. 2, the sediment 3a in FIG. 2 settles so as to close the flow path of the capillary tube at the lower part of the spiral part of the capillary tube because the capillary tube 3 is arranged to rotate spirally with respect to the ground. .
Further, the ink in a thin state of the pigment is present on the upper part of the spiral tubule.
Therefore, in the thin tube, between the ink tank 1 and the head 2, the ink portion having a low pigment concentration and the settled pigment portion are alternately arranged.

  In this state, when the ink jet printer is put into an operating state from a long rest state and the ink is discharged from the ink head 2, the precipitated pigment portion is first pushed out and stirred by the ink portion having a low pigment concentration. Therefore, it is possible to reduce the amount of ink consumed until all the pigment that has settled after the rest period of the inkjet printer melts into the ink and reaches the normal pigment concentration.

It will be described in detail with reference to the graph of FIG. 3 that the amount of ink consumed until all the settled pigment is melted in the ink and reaches the normal pigment concentration can be reduced.
FIG. 3 is a graph for explaining the effect of the first embodiment of the present invention.

In FIG. 3, the vertical axis represents the whiteness of the ink ejected from the head, where the whiteness in a normal use state is 0, and the whiteness reduction rate is shown.
The horizontal axis indicates the ink consumption until the whiteness of normal ink is achieved.
A white triangle is a conventional thin tube (tube) (flat channel) arranged in a flat shape, and the length of the thin tube is 240 cm.
The black circle is the case of the circular flow channel of the present invention, and the length of the tube is also 240 cm.

In FIG. 3, a titanium oxide pigment that is heavily precipitated is used for the ink. After 10 days of rest, the ink is printed on a transparent medium, and the L * value (whiteness) of the printed material is measured.
The measurement conditions in FIG. 3 are as follows.
Printer used EPSON PX-G930
Media used: KOKUYO OHP film Ink composition for inkjet printers:
Titanium dioxide (average particle size 200nm) 10% by mass
Dispersant (styrene-acrylic acid copolymer) 2% by mass
1,2-hexanediol 5% by mass
Glycerin 10% by mass
Triethanolamine 0.9% by mass
BYK-348 (Big Chemie Japan Co., Ltd.) 0.5% by mass
Ultra pure water remaining
100% by mass

Evaluation method Solid ink is printed on a transparent medium with Duty 100% using a printer. After drying for 2 hours or more, the color is measured with a colorimeter (Spectrolino (GretagMacbeth)). The color measurement method was carried out by placing a black sheet of black solid printed on EPSON photographic paper <Krispia> using EPSON PM-A700 under the printed matter. The L * value obtained by the color measurement is defined as the whiteness value, and the L * value is used as a reference value. Thereafter, the printer was left unused, the ink pigment was allowed to settle, and printing and colorimetry were similarly performed after 10 days. Then, the reduction rate of the L * value was obtained and evaluated for each ink consumption of the printed matter.
The results are shown in Table 1.

As shown in Table 1, in the conventional flat flow path, the maximum decrease rate of whiteness is reduced to 30.4%, and about 7 ml of ink is wasted before the normal whiteness is restored. .
On the other hand, in the circular flow channel of the present application, when the length of the narrow tube is the same 240 cm, as shown in the figure, the maximum decrease rate of whiteness is 8.3%, which is from the normal whiteness. It can be understood that there is little divergence and less wasted ink consumption.
This is because, as shown in FIG. 2, the pigment that settles in the capillary tube settles in a form that divides the lower part of the plurality of spiral portions and closes the capillary tube, and with the ejection of ink from the head after pausing, Since the agitation is performed so as to extrude the precipitated pigment, it can be estimated that the whiteness close to that of normal ink is obtained from the time of resumption.

  In addition, the thin tube is formed of a flexible material, and is fixed to the printer main body so as to be capable of weak vibration along with the movement of the head. By adopting a configuration in which the stirring action of the ink with respect to the precipitated pigment occurs, it is possible to achieve the pigment concentration of a normal ink in a shorter time.

  Next, a second embodiment of the present invention and its operation will be described below.

FIG. 5C shows a second embodiment of the present invention, which has the same configuration as the state where the ink tank (cassette) 1 and the head 2 shown in FIG. 1 is different from FIG. 1 in that, in FIG. 5 (c), the thin tubes are arranged horizontally, whereas the thin tubes are curved in a wave shape in the vertical direction.
The capillary shown in FIG. 5 (c) has a diameter of 2 mm, and the difference between the wavy top and bottom is 3 cm or less.

  Next, the operation of leveling the concentration difference of the sedimentary substance in a short time in the liquid supply system that intermittently supplies the liquid containing the sedimentary substance in the second embodiment of the present invention via the thin tube is illustrated. 6 will be described.

In FIG. 6 (a), as in FIG. 2, the sediment 7a settles so as to close the flow path of the narrow tube at the lower part of the corrugated portion of the narrow tube because the narrow tube 7 is arranged in a wave shape with respect to the ground. .
Further, the ink in a thin state of the pigment is present on the upper portion of the wavy tubule.
Accordingly, in FIG. 6 (a) as well as in FIG. 2, a state in which the ink portion having a low pigment concentration and the settled pigment portion are alternately arranged between the ink tank 1 and the head 2 not shown in the flow path of the thin tube. It has become.

In this state, when the ink jet printer is changed from a long rest state to an operation state and the ink is discharged from the ink head 2, first, the ink portion having a low pigment concentration is used as shown in FIGS. 6B and 6C. As shown, the settled pigment portion is pushed up.
When the ink is further discharged from this state, as shown in FIG. 6 (d), the pigment part diffuses and diffuses as it descends from the apex of the wave-like part of the thin tube 7. It is possible to level out the difference in concentration of the sedimentary substance in a short time.

  In this way, since the pushed-up pigment part uses the diffusion when descending from the top of the tubules arranged in a wave shape, the wave shape is increased in the inclination along the liquid flow direction. It is desirable that the descending direction is steeper than the direction. (While the wavy rising portion is steep, the steep portion of the pigment lowering is useful for diffusion, but the rising portion works as a push-up resistance, so a steep one is not suitable.)

The wavy flow path in the second embodiment can reduce the amount of ink consumed until all of the settled pigment is melted in the ink to reach the normal pigment concentration, compared with the circular flow path in the first embodiment. Will be described in detail with reference to the graph of FIG.
FIG. 7 is a graph for explaining the effect of the second embodiment of the present invention.

In FIG. 7, as in FIG. 3, the vertical axis represents the whiteness of the ink ejected from the head, and the whiteness in a normal use state is set to 0, indicating the rate of decrease in whiteness.
The horizontal axis indicates the ink consumption until the whiteness of normal ink is achieved.
The open triangle is the same circular channel as in FIG. 3, and the length of the tube is 480 cm.
A black circle is the case of the wavy channel in the second embodiment, and the length of the tube is 210 cm because it is wavy.

In FIG. 7, as in FIG. 3, a titanium oxide pigment with a strong sedimentation is used for the ink, and after 10 days rest, printing is performed on a transparent medium, and the L * value (whiteness) of the printed matter is measured.
The measurement conditions in FIG. 7 are the same as in FIG.
Printer used EPSON PX-G930
Media used: KOKUYO OHP film Ink composition for inkjet printers:
Titanium dioxide (average particle size 200nm) 10% by mass
Dispersant (styrene-acrylic acid copolymer) 2% by mass
1,2-hexanediol 5% by mass
Glycerin 10% by mass
Triethanolamine 0.9% by mass
BYK-348 (Big Chemie Japan Co., Ltd.) 0.5% by mass
Ultra pure water remaining
100% by mass

Evaluation method Solid ink is printed on a transparent medium with Duty 100% using a printer. After drying for 2 hours or more, the color is measured with a colorimeter (Spectrolino (GretagMacbeth)). The color measurement method was carried out by placing a black sheet of black solid printed on EPSON photographic paper <Krispia> using EPSON PM-A700 under the printed matter. The L * value obtained by the color measurement is defined as the whiteness value, and the L * value is used as a reference value. Thereafter, the printer was left unused, the ink pigment was allowed to settle, and printing and colorimetry were similarly performed after 10 days. Then, the reduction rate of the L * value was obtained and evaluated for each ink consumption of the printed matter.
The results are shown in Table 2.

As shown in Table 2, in the circular flow path, the maximum decrease rate of the whiteness is decreased to 8.3%, and about 22 ml of ink is wasted before the normal whiteness is restored.
On the other hand, in the wavy flow path, when the length of the narrow tube is 210 cm, as shown in the figure, the maximum decrease rate of the whiteness is 5.0%, and the deviation from the normal whiteness is small. It can be understood that the wasteful ink consumption is as small as 13 ml.

As an embodiment of the present invention, in addition to the downward spiral capillary shown in FIG. 2 for explaining the principle, for example, the following one shown in FIG. 5 may be used.
A large number of continuous, substantially circular tubules as shown in FIG. 5 (a) in which the vertical height difference in the length direction of the tubule is greater than the inner diameter of the tubule.
A large number of continuous sine-shaped or corrugated tubules as shown in FIG. 5 (c), in which the vertical height difference in the length direction of the tubule is greater than the inner diameter of the tubule.
A capillary that is curved into a large number of continuous triangles or rectangles as shown in FIG. 5 (b) or (d), in which the height difference in the vertical direction in the length direction of the capillary is greater than the inner diameter of the capillary.
-Any combination of the above spiral or substantially circular shapes, sine shapes, corrugations, triangles or rectangles.
・ In FIGS. 5 (a) to 5 (d), the ink tank (cassette) and the head are arranged horizontally, but when the ink jet printer is installed, the ink tank and the head have a height difference in the vertical direction. The ink supply pipes may be arranged vertically or obliquely between the two as shown in FIG. 5 (e) or (f).
As described above, the configuration is not limited to the above-described configuration as long as the flow rate of flowing in the narrow tube can be supplied while providing a stirring effect by installing the resistance portion so as to change in the same narrow tube.

  In the above description, an example of an ink jet printer using pigment ink is described. However, the present invention does not necessarily need to be a pigment of ink as a sedimentary substance, and a liquid containing a sedimentary substance is placed in a tube. Needless to say, the present invention can be applied to other uses as long as the liquid supply system supplies intermittently through the liquid supply system.

It is a figure which shows typically the state which the pigment settled in the prior art example which connected between the ink tank and the head 2 with the thin pipe | tube (ink supply pipe | tube) arrange | positioned horizontally. FIG. 4 is a diagram for explaining the principle of realizing the pigment concentration leveling that can shorten the time until the precipitated pigment reaches the normal pigment concentration after the rest period of the inkjet printer in the present invention. It is a graph explaining that it is possible to reduce the amount of ink consumed until all of the precipitated pigment is melted into the ink and reaches a normal pigment concentration. It is a figure which shows the arrangement | positioning relationship between an ink tank, a head, and an ink supply tube in the inkjet printing apparatus carrying the conventional ink supply mechanism. It is a figure which shows another embodiment of the ink supply pipe | tube of this invention. It is a figure explaining the effect | action which equalizes the density | concentration difference of the sedimentation substance in the 2nd Embodiment of this invention in a short time. In a 2nd embodiment, it is a graph explaining that the amount of consumption of ink can be decreased until all the settled pigment melts into ink and reaches a normal pigment concentration.

Explanation of symbols

1: Ink tank 2: Head 3, 7: Ink supply tube (narrow tube)
3a, 7a: Precipitating substances (pigments)
3b: Supernatant ink (light ink)
r: narrow tube (ink supply tube) inner diameter H: height of the region D: region

Claims (11)

A liquid supply system for supplying a liquid containing a sedimentary substance through a thin tube,
A liquid supply system, wherein a region having a height difference in a direction in which the liquid is supplied is provided in at least a part of the thin tube, the width being larger than the inner diameter of the thin tube.   The liquid supply system according to claim 1, wherein the region is formed in a spiral or circular arrangement.   The liquid supply system according to claim 1, wherein the region portion has an arrangement configuration including a curved portion.   The liquid supply system according to claim 3, wherein the curved portion is wavy.   5. The liquid supply system according to claim 3, wherein the curved portion or the wavy slope has a steeper downward direction than the upward direction of the liquid.   The liquid supply system according to claim 1, wherein the region portion is configured in a plurality or continuously.   7. An ink jet printer comprising the liquid supply system according to claim 1, wherein the thin tube connects an ink tank and a head in an ink jet printer that uses pigment ink as the sedimentary substance. An ink jet printer characterized by being an ink supply tube.   The ink jet printer, wherein the ink tank and the head are disposed substantially horizontally when the ink jet printer is installed, and the ink supply pipe connects the both substantially horizontally.   An ink jet printer wherein the ink tank and the head are arranged with a height difference in the vertical direction when the ink jet printer is installed, and the ink supply pipe connects the two vertically or obliquely.   9. The ink supply pipe according to claim 8, wherein the ink supply pipe is formed of a flexible material, and is fixed so as to be able to vibrate with the movement of the head, so that a stirring action is generated with respect to the settled pigment. The inkjet printer described in 1.   The inkjet printer according to claim 8, wherein the liquid pigment contains titanium oxide.

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