JP2008073856A - Liquid container, liquid droplet delivering apparatus, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid container capable of surely preventing moisture from evaporating from a recording liquid and smoothly following that the amount of remaining of the recording liquid is decreased, by a simple constitution. <P>SOLUTION: The liquid container 3 used for a liquid feeding system which keeps the recording liquid in the liquid container penetrative into a nozzle and suppliable with no forcible force such as a pump and generates a negative pressure in the recording liquid in the nozzle depending on a positional relation of the nozzle face and the liquid level in the liquid container. The liquid container has therein the recording liquid 1 and a non-volatile liquid 2 which has a lighter specific gravity than the recording liquid, has no possibility of mixing with the recording liquid, and has a fluidity at least equal to that of the recording liquid (for example, a silicone oil), is capable of communicating with the space above the non-volatile liquid 2 with the outside of the liquid container 3, and leaks no content liquid outside. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a liquid container, a droplet discharge device, and an image forming apparatus. Technical fields to which the present invention relates include inkjet printers, copiers, multifunction machines, and fax machines having an inkjet recording system. In addition, as an application field of the present invention, a liquid crystal color filter manufacturing apparatus using an ink jet recording technique is exemplified.

Patent Document 1 describes an invention relating to an ink cartridge for an ink jet printer that can perform ink ejection control appropriate for both a minute pressure change and a large pressure change.
In the invention described in Patent Document 2, at least a part of the backflow prevention fluid layer is immersed in each ink tank portion, and a floating body provided with an identification display such as an ink color display for the corresponding ink tank portion is disposed. ing.

  Patent Document 3 discloses an invention related to a discharge liquid storage container that stores a liquid content discharged through a pen tip, a coating destination, a printer head, etc. in a free state, such as a writing instrument, an applicator, a cosmetic container, and an ink tank cartridge of an ink jet printer. Is described. In this configuration, the lid body having a capillary surface capable of absorbing the inner solution is placed in contact with the interface of the content liquid in which the capillary surface is accommodated in a free state in a state having movement resistance with respect to the inner wall surface of the container. In addition, the discharge resistance container is provided with means for reducing the movement resistance from the resistance for the outside air to enter the content liquid side of the lid body.

  Patent Document 4 discloses a writing instrument or application that can store the liquid to be discharged through an outlet such as a pen tip, an application destination, or a printer head in a so-called free state in which the liquid storage material such as a fiber converging body does not store. Inventions relating to discharge liquid storage containers such as tools, cosmetic containers and ink tank cartridges of ink jet printers are described. And in the structure, it consists of a container body having a discharge port and a lid body having a vent hole, and contains the content liquid to be discharged outside from the discharge port in the container in a free state, and the interface of this content liquid The follower fluid that is substantially incompatible with the content liquid and whose specific gravity is less than or equal to the value of the content liquid is arranged in layers so as to follow the movement of the interface accompanying the volume reduction due to the discharge of the content liquid. In the storage container, the lid body is a liquid storage container having a temporary follower fluid storage chamber having a volume equal to or larger than a volume in which the follower fluid is stored and arranged.

  The invention described in Patent Document 5 is a writing instrument that can store a liquid content discharged through a discharge port such as a pen tip, a coating destination, or a printer head in a so-called free state in which a liquid storage material such as a fiber converging body is not stored. And an applicator, a cosmetic container, and an ink tank cartridge of an ink jet printer. An object of the present invention is to provide a liquid storage container or the like for supplying a liquid such as ink without waste to a pen or a recording head as a recording unit without waste.

  The invention described in Patent Document 6 relates to a liquid storage container for stably supplying a liquid such as ink without waste to a liquid using apparatus such as a pen as a recording unit or a recording head or a recording apparatus. Therefore, the object is to provide a liquid storage container that can obtain higher reliability with respect to stabilization of negative pressure and that does not cause liquid leakage.

  The invention described in Patent Document 7, for example, supplies a liquid such as ink to a recording head or a pen as a liquid use unit without waste and stably from an ink tank or the like as a liquid storage unit. The present invention relates to a liquid communication structure for discharging gas present in a use section to a liquid storage section, a liquid supply system using the structure, and an ink jet recording apparatus using the system.

  The invention described in Patent Document 8 can ensure the reliability of manufacturing the ink storage container used in the ink jet recording apparatus, make it possible to use the ink well, and the ink supply changes in the environment. It is difficult to be affected by the above.

The invention described in Patent Document 9 includes an ink tank that stores ink, and a recording head that discharges ink supplied from the ink tank from a plurality of nozzles, and uses the ink as a sheet material such as paper or an OHP film. The present invention relates to an ink jet image forming apparatus, such as a printer, that forms an image on a sheet material. In an ink jet image forming apparatus, ink is applied to a recording head even when the nozzle forming area width of the recording head is wide. The object is to prevent a supply shortage from occurring and to prevent image quality from deteriorating.
The specific configuration of the ink jet printer includes an ink tank for storing ink, a recording head for discharging ink supplied from the ink tank from a plurality of nozzles, and the like, and the recording head is disposed at a position higher than the ink tank. Thus, the ink in the recording head is set to a negative pressure due to the water head difference between the ink tank and the recording head.

JP 2001-277777 A Japanese Patent Laid-Open No. 2003-341084 JP 2004-148753 A JP 2004-175055 A JP 2004-306394 A JP 2004-188720 A JP 2004-122500 A JP 2003-191488 A JP-A-2005-212170

  As described above, Patent Documents 1 to 4 disclose a backflow preventer that moves with a highly viscous fluid or interface so that the ink in the container does not directly contact the atmosphere. However, these backflow preventers and the like generate viscosity resistance and frictional resistance with the wall surface, and are not suitable for making a water head difference based on the liquid level.

  In addition, as in the inventions described in Patent Documents 5 to 8 and the like, a method of forming a negative pressure by forming a film body in a container and pressing it with a spring is also known. However, this complicates the structure and necessitates cleanliness management and welding of the film body (film, etc.), which increases the number of steps.

  Furthermore, as described in Patent Document 9, although there is an invention that focuses on negative pressure due to a water head difference, this Patent Document 9 does not refer to ink moisturization in the case, and makes the ink stable for a long time. In order to use it, it is necessary to consider moisturizing.

Therefore, the first object of the present invention is to reliably prevent the evaporation of moisture from the recording liquid, and to the case where the remaining amount of the recording liquid is reduced or continuous supply during printing. However, it is to provide a liquid container that can follow without resistance with a simple configuration at low cost.
A second object of the present invention is to provide a droplet discharge device provided with the liquid container.
A third object of the present invention is to provide an image forming apparatus provided with the above-described droplet discharge device.

According to the first aspect of the present invention, the recording liquid in the liquid container communicates to the inside of the nozzle and can be continuously supplied without a forced force such as a pump, and the positional relationship between the nozzle surface and the liquid surface in the liquid container. A liquid container for use in a liquid supply system that generates a negative pressure in the recording liquid in the nozzle,
A recording liquid and a non-volatile liquid that has a lighter specific gravity than the recording liquid and does not mix with the recording liquid and has a fluidity equal to or higher than that of the recording liquid, and a space above the non-volatile liquid and the space A liquid container characterized in that it can communicate with the outside of the liquid container, and the content liquid does not leak to the outside.

The liquid container according to the invention of claim 1 is also effective when the non-volatile liquid reacts with the recording liquid to form a film at the interface with the recording liquid. In this liquid container, by forming a film at the interface between the recording liquid and the non-volatile liquid, it is possible to more reliably prevent evaporation of evaporative components in the recording liquid, for example, evaporation of moisture (from the recording liquid). is there.
In addition, since the non-volatile liquid is a fluid that has low viscosity and is easy to flow, the flexible film follows and the film follows even when the remaining amount of the recording liquid is reduced or continuous supply during printing. If not, a new interface where the recording liquid and the non-volatile liquid come into contact with each other is generated, and a new film is formed.

The invention of claim 1 is also effective when the non-volatile liquid generates a film at the interface with the atmosphere when it reacts with the atmosphere in the upper space. In this liquid container, it is possible to more reliably prevent moisture evaporation from the recording liquid by forming a film at the interface between the atmosphere and the nonvolatile liquid.
In addition, since the non-volatile liquid is a fluid that has low viscosity and is easy to flow, the flexible film follows and the film follows even when the remaining amount of the recording liquid is reduced or continuous supply during printing. If not, the non-volatile liquid is newly exposed to the atmosphere, and a new film is formed.

Further, the invention of claim 1 is particularly effective when these films have conductivity. In this case, the remaining amount detecting means capable of detecting the remaining amount of the recording liquid using the conductivity. A liquid container provided near the bottom of the container can be configured. And as said remaining amount detection means, an electrode (for example, electrode pin) is employable, for example.
That is, in this liquid container, at least one of the non-volatile liquid and the film generated thereby is made conductive, and a mechanism for detecting the remaining amount of the recording liquid using this conductivity is provided. It is possible to reliably detect that the amount of the liquid becomes less than a predetermined amount or that the liquid container is empty. Further, when an electrode is used as the remaining amount detecting means, the remaining amount detecting mechanism can be configured at low cost.

According to a second aspect of the present invention, the liquid container according to the first aspect is provided, and a liquid droplet ejecting unit having a nozzle surface for ejecting the recording liquid supplied from the liquid container as a liquid droplet is provided. A droplet discharge device.
This droplet discharge apparatus is usually configured by providing a recording head (droplet discharge head) having a large number of nozzles (droplet discharge holes) and the liquid container for supplying a recording liquid thereto. In this droplet discharge device, the liquid container is, for example, a main tank (ink cartridge) connected via an ink supply tube, and the droplet ejecting means is, for example, a recording head in which a large number of nozzles are formed. .

  A third aspect of the invention includes the droplet discharge device according to the second aspect, and an image is formed on a recording material (paper or the like) by ink droplets discharged from the droplet discharge device. The image forming apparatus.

  In the liquid container according to the first aspect, it is possible to surely prevent moisture evaporation from the recording liquid by covering the surface where the recording liquid comes into contact with the air with the nonvolatile liquid. Further, since the non-volatile liquid is a fluid having a low viscosity and is easy to flow, it can follow without resistance even when the remaining amount of the recording liquid is reduced or continuous supply at the time of printing.

  Since the liquid droplet ejection device according to the second aspect is equipped with the liquid container according to the first aspect, the above-described effects of the liquid container can be obtained.

  An image forming apparatus according to a third aspect includes the droplet discharge device according to the second aspect, and forms an image on a recording material with ink droplets discharged from the droplet discharge device. The effect of the liquid container is obtained, and a high-quality image can be stably formed.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[First embodiment]
FIG. 1 shows an embodiment of the invention of claim 1. The recording liquid 1 and the non-volatile liquid 2 are stored on the upper surface of the liquid container 3 to prevent the moisture of the recording liquid from evaporating. The atmosphere communication port 5 is covered with a gas permeable member 6 so that only gas can be communicated. A supply port 10 is provided at the bottom of the container, and a spherical member 12 is pressed against a seal member 11 by a spring 13 to be sealed.

  The liquid container 3 is preferably made of a material having low air permeability such as PP (polypropylene) or PE (polyethylene), and is more preferably provided with an aluminum coating or the like. As the non-volatile liquid 2, for example, silicone oil (eg, TSF451 series manufactured by GE Toshiba Silicone) is desirable, but besides that, oil oil (specific gravity 0.93 to 0.94), soybean oil (specific gravity 0.91 to 0.91) 0.92) and polybutene (specific gravity of about 0.8 to 0.9) can also be used. Further, the viscosity of the non-volatile liquid 2 is very desirable if it is about the same as that of the recording liquid, but it may be about 1000 mPa · s or less. The gas permeable member 6 has a vent hole with water repellency, and is made of, for example, a membrane member obtained by stretching PTFE (polytetrafluoroethylene).

[Second Embodiment]
In FIG. 2, a recording liquid 1 is stored in a liquid container 3 and a non-volatile liquid 2 is stored on the upper surface thereof, and a film body 7 a is generated at the interface between the non-volatile liquid 2 and the recording liquid 1. The non-volatile liquid 2 prevents moisture evaporation from the recording liquid. The atmosphere communication port 5 is covered with a gas permeable member 6 so that only gas can be communicated. Depending on the orientation of the container during handling, the film may be broken due to the weight of the recording liquid, or the film may move along the liquid surface of the recording liquid, but between the recording liquid and the atmosphere in the container. It works to prevent the non-volatile liquid from entering and constantly evaporating water from the recording liquid.

  FIG. 3 shows an example of a state when the recording liquid 1 is reduced in the liquid container 3 of FIG. The film body 7a generated at the interface between the recording liquid 1 and the non-volatile liquid 2 follows the decrease of the recording liquid 1, but cannot follow the recording liquid at a certain point, and a tear 8a is generated in the film body. The non-volatile liquid quickly flows into the tear 8a and comes into contact with the recording liquid 1, whereby a new film is generated, and the film body 7a and the non-volatile liquid 2 prevent moisture evaporation from the recording liquid. The atmosphere communication port 5 is covered with a gas permeable member 6 so that only gas can be communicated.

[Third embodiment]
In FIG. 4, the recording liquid 1 is stored in the liquid container 3 and the non-volatile liquid 2 is stored on the upper surface thereof, and a film body 7 b is generated at the interface between the non-volatile liquid 2 and the atmosphere 4. The liquid 2 prevents water evaporation from the recording liquid 1. The atmosphere communication port 5 is covered with a gas permeable member 6 so that only gas can be communicated. However, since the non-volatile liquid used in this embodiment reacts with the atmosphere to form a film, it is necessary to avoid exposure to the atmosphere during handling or to reduce the area that is exposed to the atmosphere as much as possible. is there.

  FIG. 5 shows an example of a state when ink is reduced in the liquid container 3 of FIG. The film body 7b generated at the interface between the atmosphere 4 and the non-volatile liquid 2 follows the decrease in the recording liquid 1, but cannot follow the recording liquid at a certain point, and a tear 8b is generated in the film body 7b. When the non-volatile liquid 2 quickly flows into the tear 8b and touches the atmosphere, a new film 7b is generated, and the film body 7b and the non-volatile liquid 2 prevent moisture evaporation from the recording liquid 1. The atmosphere communication port 5 is covered with a gas permeable member 6 so that only gas can be communicated.

  In FIGS. 3 and 5, the end portions of the film bodies 7a and 7b are in close contact with the liquid container 3 and the positions thereof are fixed. However, the present invention is not limited to this, and the close contact force of the end portions of the film bodies is weak. It may be such that the film body lowers as it falls.

[Fourth Embodiment]
In the embodiment shown in FIG. 6, when the non-volatile liquid and / or the generated film has conductivity, the recording liquid 1 installed near the bottom of the liquid container 3 when the recording liquid 1 almost disappears. When the non-volatile liquid 2 comes into contact with the remaining amount detecting means (here, the electrode 9), the electrode 9 is energized to reliably detect that there is almost no recording liquid in the liquid container 3 (for example, ink container). Can do.

Next, an example of an image forming apparatus according to the present invention provided with the droplet discharge head or the droplet discharge apparatus according to the present invention will be described with reference to FIGS. FIG. 7 is an explanatory side view for explaining the entire configuration of the apparatus, and FIG. 8 is an explanatory plan view of a main part of the apparatus.
In this image forming apparatus, a carriage 103 is slidably held in a main scanning direction by a guide rod 101 and a guide rail 102 which are horizontally mounted on left and right side plates (not shown), and a timing belt 105 is slid by a main scanning motor 104. Then, moving scanning is performed in the direction indicated by the arrow (main scanning direction) in FIG.

The carriage 103 includes, for example, a recording head 107 including four droplet ejection heads that eject ink droplets of each color of yellow (Y), cyan (C), magenta (M), and black (Bk). A plurality of ink ejection openings are arranged in a direction crossing the main scanning direction, and are mounted with the ink droplet ejection direction facing downward. In addition, as a droplet discharge head constituting the recording head 107, a droplet discharge head using a piezoelectric actuator such as a piezoelectric element is used.
The carriage 103 is also equipped with a sub-tank 108 for each color for supplying each color ink to the recording head 107. Ink is supplied to the sub tank 108 from a main tank (ink cartridge) through an ink supply tube (not shown).

  In this embodiment, the sub-tank 108 (ink tank) and the recording head 107 constitute a droplet discharge device according to the present invention. The recording head 107 is arranged at a position higher than the sub-tank 108, and the sub-tank 108 and the recording head 107. The ink in the recording head 107 is maintained at a negative pressure due to a water head difference from the ink inside. The recording head 107 may be configured by the droplet discharge head according to the present invention, and the sub tank 108 may be separately provided. Alternatively, the ink cartridge may be mounted without using the sub tank.

  On the other hand, as a paper feeding unit for feeding paper 112 stacked on a paper stacking unit (pressure plate) 111 such as a paper feeding cassette 110, a half-moon roller (separately feeding paper 112 one by one from the paper stacking unit 111) A separation pad 114 made of a material having a large friction coefficient is provided opposite to the sheet feeding roller 113 and the sheet feeding roller 113, and the separation pad 114 is urged toward the sheet feeding roller 113 side.

  As a transport unit for transporting the paper 112 fed from the paper feed unit below the recording head 107, a transport belt 121 for electrostatically attracting and transporting the paper 112, and a paper feed unit A counter roller 122 for transporting the paper 112 fed through the guide 115 while sandwiching it between the transport belt 121 and the paper 112 fed substantially vertically upward is changed by about 90 ° and copied on the transport belt 121. A conveying guide 123 for adjusting the pressure and a tip pressure roller 125 urged toward the conveying belt 121 by a pressing member 124. In addition, a charging roller 126 that is a charging unit for charging the surface of the conveyance belt 121 is provided.

  Here, the conveyance belt 121 is an endless belt, is stretched between the conveyance roller 127 and the tension roller 128, and the conveyance roller 127 is rotated from the sub-scanning motor 131 via the timing belt 132 and the timing roller 133. By doing so, it is configured to circulate in the belt conveyance direction (sub-scanning direction) of FIG. A guide member 129 is disposed on the back side of the conveyance belt 121 in correspondence with the image forming area formed by the recording head 107.

As shown in FIG. 8, a slit disk 134 is attached to the shaft of the transport roller 127, and a sensor 135 that detects the slit of the slit disk 134 is provided. An encoder 136 is configured.
The charging roller 126 is arranged so as to contact the surface layer of the conveyor belt 121 and rotate following the rotation of the conveyor belt 121, and applies 2.5N to both ends of the shaft as a pressing force.

  Further, as shown in FIG. 8, an encoder scale 142 having slits is provided on the front side of the carriage 103, and an encoder sensor comprising a transmissive photosensor that detects the slits of the encoder scale 142 on the front side of the carriage 103. The encoder 144 for detecting the position of the carriage 103 in the main scanning direction (position with respect to the home position) is configured.

Further, as a paper discharge unit for discharging the paper 112 recorded by the recording head 107, a separation unit for separating the paper 112 from the conveying belt 121, a paper discharge roller 152 and a paper discharge roller 153, and paper discharge A paper discharge tray 154 for stocking the paper 112 to be printed.
A double-sided paper feeding unit 161 is detachably mounted on the back. The double-sided paper feeding unit 161 takes in the paper 112 returned by the reverse rotation of the transport belt 121, reverses it, and feeds it again between the counter roller 122 and the transport belt 121.

In the image forming apparatus configured as described above, the sheets 112 are separated and fed one by one from the sheet feeding unit, and the sheet 112 fed substantially vertically upward is guided by the guide 115, and includes the conveyance belt 121 and the counter roller 122. The leading end is guided by the conveying guide 123 and pressed against the conveying belt 121 by the leading end pressure roller 125, and the conveying direction is changed by approximately 90 °.
At this time, a positive voltage output and a negative output are alternately repeated from the high voltage power supply to the charging roller 126 by a control circuit (not shown), that is, an alternating voltage is applied, and a charging voltage pattern in which the conveying belt 121 alternates, that is, In the sub-scanning direction, which is the circumferential direction, plus and minus are alternately charged in a band shape with a predetermined width. When the paper 112 is fed onto the conveyance belt 121 charged alternately with plus and minus, the paper 112 is attracted to the conveyance belt 121 by electrostatic force, and the paper 112 is conveyed in the sub-scanning direction by the circular movement of the conveyance belt 121. Is done.

Therefore, by driving the recording head 107 according to the image signal while moving the carriage 103, ink droplets are ejected onto the stopped paper 112 to record one line, and after the paper 112 is conveyed by a predetermined amount, Record the next line. Upon receiving a recording end signal or a signal that the trailing edge of the paper 112 has reached the recording area, the recording operation is finished, and the paper 112 is discharged onto the paper discharge tray 154.
In the case of double-sided printing, when recording on the front surface (surface to be printed first) is completed, the recording belt 112 is fed into the double-sided paper feeding unit 161 by rotating the conveyor belt 121 in the reverse direction. The paper 112 is reversed (with the back surface being the printing surface), and is fed again between the counter roller 122 and the conveyor belt 121. The timing is controlled, and the sheet is conveyed onto the conveyor bell 121 as described above. Then, after recording on the back surface, the paper is discharged onto a paper discharge tray 154.

  Note that the image forming apparatus according to the present invention can also be applied to a printer, a facsimile machine, a copying machine, a multi-function machine thereof, and the like. Further, the present invention can also be applied to a droplet discharge head or a droplet discharge device that discharges a liquid other than ink, such as a DNA sample, a resist, or a pattern material, or an image forming apparatus that includes these.

Next, the recording liquid and nonvolatile liquid incorporated in the liquid container of the present invention will be described.
The recording liquid used in the present invention can be either a pigment or a dye as a color material, and can also be used by mixing them.

<Pigment>
Although there is no limitation in particular in the pigment used for the recording liquid of this invention, For example, the pigments listed below are suitable. Moreover, you may use these pigments in mixture of multiple types.
Examples of organic pigments include azo, phthalocyanine, anthraquinone, quinacridone, dioxazine, indigo, thioindigo, perylene, isoindolenone, aniline black, azomethine, rhodamine B lake pigment, and carbon black. It is done.
Examples of inorganic pigments include iron oxide, titanium oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, bitumen, cadmium red, chrome yellow, and metal powder.
The particle diameter of these pigments is preferably 0.01 to 0.30 [mu] m. If the particle diameter is 0.01 [mu] m or less, the light resistance and feathering are deteriorated because the particle diameter approaches that of the dye. On the other hand, if it is 0.30 μm or more, clogging of the discharge port or clogging with a filter in the printer occurs, and the discharge stability cannot be obtained.

  The carbon black used in the black pigment ink is carbon black produced by the furnace method and the channel method, the primary particle size is 15 to 40 mμm (millimicron), and the specific surface area by the BET method is 50 to 300 square meters / g. A DBP oil absorption of 40 to 150 ml / 100 g, a volatile content of 0.5 to 10%, and a pH value of 2 to 9 are preferable. As such a thing, for example, no. 2300, no. 900, MCF-88, no. 33, no. 40, no. 45, no. 52, MA7, MA8, MA100, no. 2200B (Mitsubishi Chemical), Raven700, 5750, 5250, 5000, 3500, 1500 (Columbia), Regal 400R, 330R, 660R, MoguL, Monarch 700, 800, 880, 900, 1000, 1100, 1300, Monarch 1400 (above, manufactured by Cabot), Color Black FW1, FW2, FW2V, FW18, FW200, S150, S160, S170, Printex 35, U, the same V, the same 140U, the same 140V, the special black 6, the same 5, the same 4A, the same 4 (manufactured by Degussa) and the like can be used, but are not limited thereto.

Specific examples of color pigments are listed below.
Examples of organic pigments include azo, phthalocyanine, anthraquinone, quinacridone, dioxazine, indigo, thioindigo, perylene, isoindolenone, aniline black, azomethine, rhodamine B lake pigment, and carbon black. Examples of inorganic pigments include iron oxide, titanium oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, bitumen, cadmium red, chrome yellow, and metal powder.

Specific examples according to color are as follows.
Examples of pigments that can be used for yellow ink include C.I. I. Pigment Yellow 1, 2, 2, 3, 12, 14, 16, 17, 17, 73, 74, 75, 83, 93, 95, 97, 98, 114, 128, 129, 151, 154, etc., but are not limited thereto.
Examples of pigments that can be used in magenta ink include C.I. I. Pigment Red 5, 7, 12, 48 (Ca), 48 (Mn), 57 (Ca), 57: 1, 112, 123, 168, 184, 202, etc. However, it is not limited to these.
Examples of pigments that can be used for cyan ink include C.I. I. Pigment blue 1, 2, 3, 15: 3, 15:34, 16, 22, 22, 60, C.I. I. Examples thereof include, but are not limited to, Bat Blue 4 and 60.
In addition, the pigment contained in each ink used in the present invention may be newly produced for the present invention.

  The above-mentioned pigments can be used as inkjet recording liquids by dispersing them in an aqueous medium using a polymer dispersant or a surfactant. As a dispersant for dispersing such organic pigment powder, a normal water-soluble resin or a water-soluble surfactant can be used.

Specific examples of water-soluble resins include styrene, styrene derivatives, vinyl naphthalene derivatives, aliphatic alcohol esters of α, β-ethylenically unsaturated carboxylic acids, acrylic acid, acrylic acid derivatives, maleic acid, maleic acid derivatives, itacon. Examples thereof include block copolymers consisting of at least two monomers selected from acids, itaconic acid derivatives, fumaric acid, fumaric acid derivatives, etc., random copolymers, or salts thereof. These water-soluble resins are alkali-soluble resins that are soluble in an aqueous solution in which a base is dissolved. Among them, a resin having a weight average molecular weight of 3000 to 20000 is used as a dispersion when used in an inkjet recording liquid. It is particularly preferred because of the advantages that it can be reduced in viscosity and can be easily dispersed.
The simultaneous use of the polymer dispersant and the self-dispersing pigment is a preferable combination because an appropriate dot diameter can be obtained. The reason is not clear, but it is thought as follows.
By containing the polymer dispersant, the penetration into the recording paper is suppressed. On the other hand, since the aggregation of the self-dispersing pigment is suppressed by containing the polymer dispersant, the self-dispersing pigment can smoothly spread in the lateral direction. Therefore, it is considered that the dots spread widely and thinly and ideal dots can be formed.

Moreover, the following are mentioned as a specific example of the water-soluble surfactant which can be used as a dispersing agent by this invention.
For example, anionic surfactants include higher fatty acid salts, alkyl sulfates, alkyl ether sulfates, alkyl ester sulfates, alkyl aryl ether sulfates, alkyl sulfonates, sulfosuccinates, alkyl allyls and alkyl naphthalene sulfonic acids. Examples thereof include salts, alkyl phosphates, polyoxyethylene alkyl ether phosphate esters, and alkyl allyl ether phosphates. Examples of the cationic surfactant include alkylamine salts, dialkylamine salts, tetraalkylammonium salts, benzalkonium salts, alkylpyridinium salts, imidazolinium salts, and the like. Furthermore, examples of the amphoteric surfactant include dimethylalkyl lauryl betaine, alkyl glycine, alkyl di (aminoethyl) glycine, imidazolinium betaine and the like. Nonionic surfactants include polyoxyethylene alkyl ether, polyoxyethylene alkyl allyl ether, polyoxyethylene polyoxypropylene glycol, glycerin ester, sorbitan ester, sucrose ester, glycerin ester polyoxyethylene ether, sorbitan Examples thereof include polyoxyethylene ethers of esters, polyoxyethylene ethers of sorbitol esters, fatty acid alkanolamides, polyoxyethylene fatty acid amides, amine oxides, and polyoxyethylene alkylamines.

In addition, the pigment can be provided with dispersibility by coating with a resin having a hydrophilic group and encapsulating the pigment.
As a method of coating a water-insoluble pigment with an organic polymer and microencapsulating, all conventionally known methods can be used. Conventionally known methods include chemical production methods, physical production methods, physicochemical methods, mechanical production methods, and the like. Specifically, the following (1) to (10) are mentioned.

That is,
(1) Interfacial polymerization method (a method in which two kinds of monomers or two kinds of reactants are separately dissolved in a dispersed phase and a continuous phase, and both substances are reacted at the interface between them to form a wall film),
(2) In-situ polymerization method (method of supplying a liquid or gas monomer and catalyst, or two reactive substances from either one of the continuous phase core particles to cause a reaction to form a wall film),
(3) In-liquid cured coating method (method of forming a wall film by insolubilizing droplets of a polymer solution containing core material particles in a liquid with a curing agent),
(4) Coacervation (phase separation) method (a method in which a polymer dispersion in which core material particles are dispersed is separated into a coacervate (concentrated phase) having a high polymer concentration and a dilute phase to form a wall membrane) ,
(5) In-liquid drying method (preparing a liquid in which a core substance is dispersed in a solution of a wall membrane material, placing the dispersion in a liquid in which the continuous phase of this dispersion is not miscible to form a composite emulsion, A method of forming a wall film by gradually removing the dissolved medium),
(6) Melt-dispersed cooling method (using a wall film material that melts into a liquid state and solidifies at room temperature when heated, this material is heated and liquefied, core material particles are dispersed therein, and it is cooled into fine particles. A method of forming a wall film),
(7) Air suspension coating method (powder core material particles are suspended in the air by a fluidized bed, and the wall membrane material coating solution is sprayed and mixed while suspended in the air stream to form a wall membrane. Method),
(8) Spray drying method (a method in which an encapsulated stock solution is sprayed and brought into contact with hot air to evaporate and dry volatile matter to form a wall film),
(9) Acid precipitation method (by neutralizing at least a part of the anionic group of the organic polymer compound containing an anionic group with a basic compound to provide solubility in water in an aqueous medium together with a coloring material) After kneading, neutralize or acidify with an acidic compound, deposit organic compounds and fix them on the colorant, then neutralize and disperse)
(10) Phase inversion emulsification method (a mixture containing an anionic organic polymer having dispersibility in water and a colorant is used as an organic solvent phase, and water is added to the organic solvent phase or water In which the organic solvent phase is charged).

  Examples of the organic polymer (resin) used as the material constituting the wall membrane material of the microcapsule include polyamide, polyurethane, polyester, polyurea, epoxy resin, polycarbonate, urea resin, melamine resin, phenol resin, and many others. Sugar, gelatin, gum arabic, dextran, casein, protein, natural rubber, carboxypolymethylene, polyvinyl alcohol, polyvinylpyrrolidone, polyvinyl acetate, polyvinyl chloride, polyvinylidene chloride, cellulose, ethyl cellulose, methyl cellulose, nitrocellulose, hydroxyethyl cellulose, Cellulose acetate, polyethylene, polystyrene, (meth) acrylic acid polymer or copolymer, (meth) acrylic acid ester polymer or copolymer, (meth) acrylic -(Meth) acrylic acid ester copolymer, styrene- (meth) acrylic acid copolymer, styrene-maleic acid copolymer, sodium alginate, fatty acid, paraffin, beeswax, water wax, hardened beef tallow, carnauba wax, albumin, etc. Can be mentioned.

  Among these, organic polymers having an anionic group such as a carboxylic acid group or a sulfonic acid group can be used. Nonionic organic polymers include, for example, polyvinyl alcohol, polyethylene glycol monomethacrylate, polypropylene glycol monomethacrylate, methoxypolyethylene glycol monomethacrylate or their (co) polymers, and 2-oxazoline cationic ring-opening polymers. Is mentioned. In particular, a complete saponified product of polyvinyl alcohol is particularly preferable because it has low water solubility and is easily dissolved in hot water but difficult to dissolve in cold water.

  Further, the amount of the organic polymer constituting the wall membrane material of the microcapsule is 1% by weight or more and 20% by weight or less based on the water-insoluble colorant such as an organic pigment or carbon black. By setting the amount of the organic polymer within the above range, the content of the organic polymer in the capsule is relatively low so that the pigment develops due to the organic polymer covering the pigment surface. Can be suppressed. If the amount of the organic polymer is less than 1% by weight, it is difficult to exert the effect of encapsulation. Conversely, if the amount exceeds 20% by weight, the color developability of the pigment is significantly reduced. In consideration of other characteristics, the amount of the organic polymer is preferably in the range of 5 to 10% by weight based on the water-insoluble colorant.

That is, since a part of the color material is exposed without being substantially covered, it is possible to suppress a decrease in color developability, and conversely, a part of the color material is not substantially exposed without being exposed. Since it is coated, it is possible to simultaneously exhibit the effect that the pigment is coated. The number average molecular weight of the organic polymers used in the present invention is preferably 2000 or more from the viewpoint of capsule production. Here, “substantially exposed” means not the partial exposure associated with defects such as pinholes and cracks, but a state where it is intentionally exposed.
Furthermore, if an organic pigment or self-dispersing carbon black, which is a self-dispersing pigment, is used as a colorant, the dispersibility of the pigment is improved even if the content of the organic polymer in the capsule is relatively low. In addition, since sufficient storage stability of the ink can be secured, it is more preferable for the present invention.

  It is preferable to select an organic polymer suitable for the microencapsulation method. For example, in the case of interfacial polymerization, polyester, polyamide, polyurethane, polyvinyl pyrrolidone, epoxy resin and the like are suitable. In the case of using the in-situ polymerization method, a polymer or copolymer of (meth) acrylic acid ester, (meth) acrylic acid- (meth) acrylic acid ester copolymer, styrene- (meth) acrylic acid copolymer, Polyvinyl chloride, polyvinylidene chloride, polyamide and the like are suitable. In the case of the liquid curing method, sodium alginate, polyvinyl alcohol, gelatin, albumin, epoxy resin and the like are suitable. In the case of the coacervation method, gelatin, celluloses, casein and the like are suitable. In addition, in order to obtain a fine and uniform microencapsulated pigment, it is possible to use all conventionally known encapsulation methods other than those described above.

  When the phase inversion method or the acid precipitation method is selected as the microencapsulation method, anionic organic polymers are used as the organic polymers constituting the wall membrane material of the microcapsules. The phase inversion method is a composite or composite of an anionic organic polymer having self-dispersibility or solubility in water and a colorant such as a self-dispersion organic pigment or self-dispersion carbon black, or a self-dispersion method. A mixture of a colorant such as a dispersible organic pigment or self-dispersing carbon black, a curing agent, and an anionic organic polymer is used as an organic solvent phase, and water is added to the organic solvent phase, or the organic solvent is submerged in water. In this method, a solvent phase is introduced and microencapsulation is performed while self-dispersion (phase inversion emulsification) is performed. In the above phase inversion method, there is no problem even if the organic solvent phase is mixed with a recording liquid vehicle or additives. In particular, it is more preferable to mix a liquid medium of a recording liquid because a dispersion liquid for recording liquid can be directly produced.

  On the other hand, in the acid precipitation method, a part or all of the anionic group of the anionic group-containing organic polymer is neutralized with a basic compound, and a colorant such as a self-dispersing organic pigment or self-dispersing carbon black, A water-containing cake obtained by a production method comprising a step of kneading in an aqueous medium and a step of neutralizing and acidifying an acidic compound to precipitate an anionic group-containing organic polymer and fixing it to a pigment, This is a method of microencapsulation by neutralizing a part or all of an anionic group using a compound. By doing in this way, the aqueous dispersion containing the anionic microencapsulated pigment which is fine and contains many pigments can be manufactured.

  Examples of the solvent used for microencapsulation as described above include alkyl alcohols such as methanol, ethanol, propanol and butanol; aromatic hydrocarbons such as benzol, toluol and xylol; methyl acetate Esters such as ethyl acetate and butyl acetate; Chlorinated hydrocarbons such as chloroform and ethylene dichloride; Ketones such as acetone and methyl isobutyl ketone; Ethers such as tetrahydrofuran and dioxane; Cellosolves such as methyl cellosolve and butyl cellosolve Etc. The microcapsules prepared by the above method are once separated from these solvents by centrifugation or filtration, and then stirred and redispersed with water and the necessary solvent, and used for the intended present invention. A recording liquid that can be used is obtained. The average particle diameter of the encapsulated pigment obtained by the above method is preferably 50 nm to 180 nm.

  By coating the resin in this way, the pigment adheres firmly to the printed material, whereby the scratching property of the printed material can be improved.

<Dye>
As the dye used in the recording liquid of the present invention, dyes classified in the color index into acid dyes, direct dyes, basic dyes, reactive dyes, and food dyes and having excellent water resistance and light resistance are used. These dyes may be used as a mixture of a plurality of types, or may be used as a mixture with other color materials such as pigments as necessary. These colorants are added within a range that does not impair the effects of the present invention.

(A) Acid dyes and food dyes C.I. I. Acid Yellow 17, 23, 42, 44, 79, 142
C. I. Acid Red 1,8,13,14,18,26,27,35,37,42,52,82,87,89,92,97,106,111,114,115,134,186,249,254 289
C. I. Acid Blue 9, 29, 45, 92, 249
C. I. Acid Black 1, 2, 7, 24, 26, 94
C. I. Food Yellow 3, 4
C. I. Food Red 7, 9, 14
C. I. Food Black 1, 2

(B) As a direct dye C.I. I. Direct yellow 1,12,24,26,33,44,50,86,120,132,142,144
C. I. Direct Red 1,4,9,13,17,20,28,31,39,80,81,83,89,225,227
C. I. Direct orange 26, 29, 62, 102
C. I. Direct blue 1,2,6,15,22,25,71,76,79,86,87,90,98,163,165,199,202
C. I. Direct black 19, 22, 32, 38, 51, 56, 71, 74, 75, 77, 154, 168, 171

(C) As a basic dye C.I. I. Basic yellow 1, 2, 11, 13, 14, 15, 19, 21, 23, 24, 25, 28, 29, 32, 36, 40, 41, 45, 49, 51, 53, 63, 64, 65 67, 70, 73, 77, 87, 91
C. I. Basic Red 2,12,13,14,15,18,22,23,24,27,29,35,36,38,39,46,49,51,52,54,59,68,69,70 73, 78, 82, 102, 104, 109, 112
C. I. Basic blue 1,3,5,7,9,21,22,26,35,41,45,47,54,62,65,66,67,69,75,77,78,89,92,93 , 105, 117, 120, 122, 124, 129, 137, 141, 147, 155
C. I. Basic Black 2,8

(D) As a reactive dye, C.I. I. Reactive Black 3, 4, 7, 11, 12, 17
C. I. Reactive Yellow 1,5,11,13,14,20,21,22,25,40,47,51,55,65,67
C. I. Reactive Red 1,14,17,25,26,32,37,44,46,55,60,66,74,79,96,97
C. I. Reactive Blue 1, 2, 7, 14, 15, 23, 32, 35, 38, 41, 63, 80, 95, etc. can be used.

<Additives and physical properties common to dyes and pigments>
In order to make the recording liquid of the present invention have desired physical properties or to prevent clogging of the nozzles of the recording head due to drying, it is preferable to use a water-soluble organic solvent in addition to the coloring material. The water-soluble organic solvent includes a wetting agent and a penetrating agent. The wetting agent is added for the purpose of preventing clogging of the nozzles of the recording head due to drying.
Specific examples of the wetting agent include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, propylene glycol, 1,3-butanediol, 1,3-propanediol, and 2-methyl-1,3-propane. Diol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, glycerin, 1,2,6-hexanetriol, 2-ethyl-1,3-hexanediol, 1,2 Polyhydric alcohols such as 1,4-butanetriol, 1,2,3-butanetriol, and petriol, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene Polyhydric alcohol alkyl ethers such as glycol monobutyl ether, triethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether and propylene glycol monoethyl ether, polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether Forehead: Nitrogen-containing heterocyclic compounds such as N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone, 2-pyrrolidone, 1,3-dimethylimidazolidinone, ε-caprolactam; formamide, N-methylformamide, Amides such as formamide and N, N-dimethylformamide; monoethanolamine, diethanolamine, triethanolamine, monoethylamine, diethylamine, triethyl And amines such as ruamine, sulfur-containing compounds such as dimethyl sulfoxide, sulfolane and thiodiethanol, propylene carbonate, ethylene carbonate, and γ-butyrolactone. These solvents are used alone or in combination with water.

Further, the penetrant is added for the purpose of improving the wettability between the recording liquid and the recording material (paper or the like) and adjusting the penetration rate of the recording liquid into the recording material. As the penetrant, those represented by the following chemical formulas (I) to (IV) are preferable. That is,
A polyoxyethylene alkylphenyl ether surfactant of the formula (I),
An acetylene glycol surfactant of the formula (II),
A polyoxyethylene alkyl ether surfactant of the formula (III) and
The polyoxyethylene polyoxypropylene alkyl ether surfactant of the chemical formula (IV) is
Since the surface tension of the liquid can be reduced, the wettability can be improved and the penetration rate can be increased.

  Other than the compounds of the above chemical formulas (I) to (IV), for example, diethylene glycol monophenyl ether, ethylene glycol monophenyl ether, ethylene glycol monoallyl ether, diethylene glycol monophenyl ether, diethylene glycol monobutyl ether, propylene glycol monobutyl ether, tetraethylene glycol chlorophenyl Use alkyl and aryl ethers of polyhydric alcohols such as ethers, nonionic surfactants such as polyoxyethylene polyoxypropylene block copolymers, fluorine-based surfactants, lower alcohols such as ethanol and 2-propanol However, diethylene glycol monobutyl ether is particularly preferable.

The surface tension of the recording liquid of the present invention is preferably 20 to 60 dyne / cm, and is further preferably 30 to 50 dyne / cm from the viewpoint of achieving both wettability with the recording material and droplet formation. preferable.
The viscosity of the recording liquid of the present invention is preferably 1.0 to 20.0 cP, and more preferably 3.0 to 10.0 cP from the viewpoint of ejection stability.
Further, the pH of the recording liquid of the present invention is preferably 3 to 11, and more preferably 6 to 10 from the viewpoint of preventing corrosion of the metal member in contact with the liquid.

  The recording liquid of the present invention can contain an antiseptic / antifungal agent. By containing an antiseptic / antifungal agent, the growth of bacteria can be suppressed, and the storage stability and image quality stability can be improved. As antiseptic / antifungal agents, benzotriazole, sodium dehydroacetate, sodium sorbate, sodium 2-pyridinethiol-1-oxide, isothiazoline compounds, sodium benzoate, sodium pentachlorophenol, and the like can be used.

  The recording liquid of the present invention can contain a rust inhibitor. By containing a rust preventive agent, a coating can be formed on the metal surface in contact with the liquid, such as a head, and corrosion can be prevented. As the rust inhibitor, for example, acidic sulfite, sodium thiosulfate, ammonium thiodiglycolate, diisopropylammonium nitrite, pentaerythritol tetranitrate, dicyclohexylammonium nitrite and the like can be used.

The recording liquid of the present invention can contain an antioxidant. By containing an antioxidant, even when radical species that cause corrosion are generated, the antioxidant can be prevented by eliminating the radical species.
Typical examples of the antioxidant include phenolic compounds and amine compounds. Examples of the phenolic compounds include hydroquinone and gallate compounds, 2,6-di-tert-butyl-p-cresol, and stearyl. -Β- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 2,2'-methylenebis (4-methyl-6-tert-butylphenol), 2,2'-methylenebis (4-ethyl- 6-tert-butylphenol), 4,4′-thiobis (3-methyl-6-tert-butylphenol), 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-4-hydroxybenzyl) benzene, tri Hindered phenols such as (3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate, tetrakis [methylene-3 (3 ′, 5′-di-tert-butyl-4-hydroxyphenyl) propionate] methane Examples of amine compounds include N, N′-diphenyl-p-phenylenediamine, phenyl-β-naphthylamine, phenyl-α-naphthylamine, N, N′-β-naphthyl-p-phenylenediamine. N, N′-diphenylethylenediamine, phenothiazine, N, N′-di-sec-butyl-p-phenylenediamine, 4,4′-tetramethyl-diaminodiphenylmethane, and the like. As the latter, sulfur compounds and phosphorus compounds are representative, but as sulfur compounds, dilauryl thiodipropionate, distearyl thiodipropionate, lauryl stearyl thiodipropionate, Examples include myristyl thiodipropionate, distearyl β, β′-thiodibutyrate, 2-mercaptobenzimidazole, dilauryl sulfide and the like, and phosphorus compounds include triphenyl phosphite, trioctadecyl phosphite, tridecyl. Examples include phosphite, trilauryl trithiophosphite, diphenylisodecyl phosphite, trinonylphenyl phosphite, distearyl pentaerythritol phosphite.

  The recording liquid of the present invention can contain a pH adjuster. Examples of the pH adjuster include hydroxides of alkali metal elements such as lithium hydroxide, sodium hydroxide, potassium hydroxide, ammonium hydroxide, quaternary ammonium hydroxide, quaternary phosphonium hydroxide, lithium carbonate, Examples include alkali metal carbonates such as sodium carbonate and potassium carbonate, amines such as diethanolamine and triethanolamine, boric acid, hydrochloric acid, nitric acid, sulfuric acid, and acetic acid.

It is a schematic sectional drawing of the liquid container which concerns on the 1st Embodiment of this invention. It is a schematic sectional drawing of the liquid container which concerns on the 2nd Embodiment of this invention. FIG. 3 is a sectional view for explaining the operation of the liquid container in FIG. 2. It is a schematic sectional drawing of the liquid container which concerns on the 3rd Embodiment of this invention. FIG. 5 is a sectional view for explaining the operation of the liquid container in FIG. 4. It is a schematic sectional drawing of the liquid container which concerns on the 4th Embodiment of this invention. 1 is an overall configuration explanatory diagram of an image forming apparatus according to the present invention. FIG. FIG. 2 is an explanatory plan view of a main part of the image forming apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Recording liquid 2 Nonvolatile liquid 3 Liquid container 5 Atmospheric communication port part 6 Gas permeable member 7a Film body 7b Film body 8a Rupture 8b Cleavage 9 Electrode 10 Supply port 11 Seal member 12 Spherical member 13 Spring 101 Guide rod 102 Guide rail 103 Carriage 104 Main scanning motor 105 Timing belt 107 Recording head 108 Sub tank 110 Paper feed cassette 112 Paper

Claims (3)

The recording liquid in the liquid container communicates to the inside of the nozzle and can be continuously supplied without forced force such as a pump, and the recording liquid in the nozzle is changed according to the positional relationship between the nozzle surface and the liquid surface in the liquid container. A liquid container used in a liquid supply system that generates negative pressure,
A recording liquid and a non-volatile liquid that has a lighter specific gravity than the recording liquid and does not mix with the recording liquid and has a fluidity equal to or higher than that of the recording liquid, and a space above the non-volatile liquid and the space A liquid container characterized in that it can communicate with the outside of the liquid container and the content liquid does not leak to the outside.   A liquid droplet ejecting apparatus comprising: the liquid container according to claim 1; and a liquid droplet ejecting unit having a nozzle surface that ejects the recording liquid supplied from the liquid container as a liquid droplet. An image forming apparatus comprising the droplet discharge device according to claim 2, wherein an image is formed on a recording material by ink droplets discharged from the droplet discharge device.

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