JP2005239974A - Recording liquid, liquid cartridge, and cartridge, device and method for discharging liquid - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a recording liquid for use in record on an object, liquid cartridge of filling the liquid, liquid-discharging cartridge for discharging the liquid onto the object, device and method for discharging the liquid, preventing an ink from non-discharge. <P>SOLUTION: The ink 2 contains a hydrophobic colloid which normally has zeta potential of at most +10 mV, and when the pH of the ink 2 becomes 4-6, the zeta potential is charged to positive. Thereby elusion of silicon, silicon compounds, etc. into the ink 2 from a circuit board 42 composed of a silicon wafer etc., and deposition of the colloid onto a heating resistor 46 of negatively being charged, are suppressed, preventing causing of kogetion on the heating resistor 46 and non-discharge of the ink by clogging resulting from precipitation thereof in an ink passage 32 and in a nozzle 43a. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a recording liquid for recording on an object, a liquid cartridge filled with liquid, a liquid ejection cartridge for ejecting liquid onto an object, a liquid ejection apparatus, and a liquid ejection method.

  The liquid is supplied to a liquid chamber provided with energy generating means such as a piezoelectric element and a heating resistance element through a fine flow path, and is pressurized by the energy generated by the energy generating means and provided in the liquid chamber. In various fields, droplets are discharged from the discharge port.

  As an example to which such a technique is applied, there is an ink jet printer apparatus that records an image or a character by ejecting ink from a head chip onto a recording paper as an object.

  A printer device using this ink jet system has advantages such as low running cost, small device size, and easy colorization of printed images. In a printer apparatus using an ink jet system, for example, ink of a plurality of colors such as yellow, magenta, cyan, and black is supplied to an ink liquid chamber of a head chip or the like.

  In this printer apparatus, the ink supplied to the ink liquid chamber or the like is pressed against the ink in the ink by a pressure generating element such as a heating resistor disposed in the ink liquid chamber, and the minute amount provided on the head chip. The ink is ejected from an ink ejection port, so-called nozzle.

  Specifically, the ink in the ink chamber is heated by a heating resistor disposed in the ink liquid chamber, bubbles are generated in the ink on the heating resistor, and the ink is ejected from the nozzles by the pressing force of the bubbles, The ejected ink is landed on a recording paper or the like as an object to print an image or a character.

  In this ink jet printer device, since the ejection characteristics when ejecting ink from the nozzles of the head chip greatly affect the image quality, the processing accuracy can be improved, for example, a silicon wafer made of silicon or silicon oxide Attention has been focused on head chips that incorporate heating resistors.

  Specifically, there is a head chip or the like in which a heating resistor is formed on a silicon wafer and an end surface of the silicon wafer is used as a flow path for introducing ink into a liquid chamber.

  In such a head chip, the surface of the silicon wafer on which the heating resistor is formed is subjected to an oxidation treatment or the like. For example, silicon or silicon oxide does not elute into the ink even when exposed to ink. In the manufacturing process, it is difficult to subject the end face of the silicon wafer to oxidation treatment, and silicon or silicon oxide may be eluted into the ink when exposed to ink.

  In particular, in the case of an ink having a pH higher than 7 and showing alkalinity, the elution of silicon from the silicon wafer becomes remarkable. The ink printed on the paper is generally made weakly alkaline so that the portion of the head chip using the metal material or the like is not oxidized.

  In this case, the dimensional accuracy of the head chip is lowered due to melting of the silicon wafer, ink ejection characteristics are deteriorated, and printing may cause problems such as degradation of image quality and non-ejection of ink.

  Further, when the silicon wafer is melted, the bonding strength of the bonding portion between the silicon wafer and other components bonded to the silicon wafer is lowered, and there is a possibility that other components are peeled off from the silicon wafer and the head chip is damaged.

  When the silicon wafer forms a liquid chamber or a flow path, the dimensional accuracy of the liquid chamber or the flow path may decrease due to dissolution of the silicon wafer, and the discharge characteristics may decrease.

  Ink from which silicon or silicon oxide has been eluted may cause the dispersion stability of the dye to decrease and the dye to precipitate in the liquid, thereby clogging the nozzle.

  The silicon or silicon oxide eluted in the ink becomes supersaturated in the ink due to volatilization of the ink solvent, and precipitates in the ink, clogs the nozzles, and may cause non-ejection of the ink. is there.

  In addition, silicon or silicon oxide eluted in the ink increases the solubility of the silicon or silicon oxide in the ink when the ink is heated by, for example, a heating resistor, and the silicon or silicon oxide is contained in the ink. May be dissolved excessively and deposited on the heating resistor by rapid cooling after discharge. That is, so-called kogation may occur. As described above, in a head chip in which kogation has occurred on the heating resistor, it becomes difficult to heat the ink properly, and there is a risk of causing non-ejection of ink.

  In order to solve the above problems, for example, the silicon wafer constituting the head chip is not exposed to ink, or the silicon wafer is subjected to surface treatment so that silicon and silicon oxide are not eluted from the silicon wafer. It has been proposed to apply. Specifically, for example, Patent Document 1 proposes to provide a layer made of SiN, TiN, TiO or the like on the surface of a silicon wafer, for example.

  However, although such a proposal can prevent silicon and silicon oxide from eluting from the silicon wafer into the ink, for example, the manufacturing cost of the head chip is increased and the manufacturing cost is increased, or the manufacturing yield is decreased. Problem arises, and the printer device becomes very expensive. In addition, when the above-described layer is provided on the surface of the silicon wafer, it is difficult to form a layer having no pinhole and a substantially uniform thickness, which causes a problem that the manufacturing yield is deteriorated.

  The above-described defects are not only caused when, for example, a silicon wafer is used for the head chip, but also when the head chip where the silicon-containing material such as a glass substrate is exposed is exposed to ink, in other words, the silicon-containing material is exposed. This occurs when the ink is alkaline in the flow path.

JP-A-9-85949

  The present invention relates to a recording liquid that can prevent silicon-containing materials and hydrophobic colloids from depositing in the liquid and thereby causing kogation to occur on the pressure generating element and clogging of the discharge port, and the recording liquid is filled. The present invention provides a liquid cartridge, a liquid discharge cartridge to which the liquid cartridge is mounted, a liquid discharge apparatus and a liquid discharge method capable of printing with high image quality using the liquid discharge cartridge.

  The present inventors include a hydrophobic colloid that has been prevented from being contained as much as an impurity in a conventional ink or the like in a liquid in which the silicon-containing material flows through the exposed flow path. Specifically, the liquid is in a normal state. That is, a hydrophobic colloid in which the zeta potential is charged to +10 mV or less when the liquid is prepared to exhibit weak alkalinity or alkalinity, and the zeta potential is positively charged when the pH of the liquid is in the range of 4 to 6 By containing, it is possible to prevent the hydrophobic colloid from depositing on the pressure generating element when the pressure generating element is negatively charged, and to prevent silicon and silicon compounds from eluting from the silicon-containing material into the liquid. The present invention that can solve the above-described problems has been completed.

  That is, the recording liquid according to the present invention is discharged to the discharge port through the liquid flow path where the silicon-containing material is exposed, and pressed by the pressure generated by the pressure generating element provided corresponding to the discharge port. When the recording liquid is weakly alkaline or alkaline, the zeta potential is charged to +10 mV or less, and the pH of the recording liquid is 4 or more. , And a hydrophobic colloid in which the zeta potential is positively charged when it is in the range of 6 or less.

  In the liquid cartridge according to the present invention, the liquid guided to the discharge port through the liquid flow path exposing the silicon-containing material is pressed by the pressure generated by the pressure generating element provided corresponding to the discharge port. It is detachably attached to a liquid ejection apparatus having ejection means for ejecting more, serves as a liquid supply source for the ejection means, has a liquid filling portion filled with liquid, and the liquid disperses or dissolves the dye and the dye. Contains a solvent and a hydrophobic colloid in which the zeta potential is charged to +10 mV or less when the liquid is weakly alkaline or alkaline, and the zeta potential is positively charged when the pH of the liquid is in the range of 4 to 6 It is characterized by that.

  A liquid discharge cartridge according to the present invention is detachably attached to a liquid discharge device that discharges liquid and adheres to an object, and a liquid filling portion filled with liquid and a liquid from which the silicon-containing material is exposed from the liquid filling portion Discharge means for discharging from the discharge port by pressing the liquid guided to the discharge port through the flow path with the pressure generated by the pressure generating element provided corresponding to the discharge port, and the liquid is a dye And a solvent for dispersing or dissolving the dye, and when the liquid is weakly alkaline or alkaline, the zeta potential is charged to +10 mV or less, and when the pH of the liquid is in the range of 4 to 6, the zeta potential is positive. It is characterized by containing a charged hydrophobic colloid.

  The liquid discharge apparatus according to the present invention discharges a liquid and adheres it to an object, and a liquid that is guided to the discharge port through a liquid channel in which the silicon-containing material is exposed is provided corresponding to the discharge port. A discharge unit that discharges from a discharge port by pressing with a pressure generated by the generating element, and a liquid cartridge that is filled with liquid and serves as a supply source of liquid to the discharge unit. The liquid disperses the dye and the dye. Alternatively, the solvent to be dissolved is charged so that the zeta potential is charged to +10 mV or less when the liquid is weakly alkaline or alkaline, and the zeta potential is charged positively when the pH of the liquid is in the range of 4 to 6 It is characterized by containing a sex colloid.

  In the liquid discharge method according to the present invention, when the liquid is discharged toward the object in order to adhere the liquid to the object, the dye, the solvent for dispersing or dispersing the dye, and the liquid are weakly alkaline or alkaline. A liquid containing a hydrophobic colloid charged with a zeta potential of +10 mV or less when the pH of the liquid is in the range of 4 or more and 6 or less when the pH of the liquid is at least positively charged. It is characterized in that it is guided to the discharge port through the liquid flow path where the material is exposed, and discharged from the discharge port by pressing with the pressure generated by the pressure generating element provided corresponding to the discharge port.

  According to the present invention, the liquid that is guided to the discharge port through the flow path in which the silicon-containing material is exposed and is pressed by the pressure generating element and discharged from the discharge port is in a normal state, that is, the liquid is weakly alkaline or alkaline. When the zeta potential is charged to +10 mV or less, the pressure generating element is negatively charged by including a hydrophobic colloid in which the zeta potential is positively charged when the pH of the liquid is in the range of 4 or more and 6 or less. Occasionally, hydrophobic colloids adhere to the pressure generating element and precipitate, and silicon and silicon compounds are prevented from eluting from the silicon-containing material into the liquid.

  According to the present invention, when the liquid is weakly alkaline or alkaline, the zeta potential is +10 mV when the liquid is guided to the discharge port through the flow path in which the silicon-containing material is exposed and pressed by the pressure generating element and discharged from the discharge port. Silicon and silicon compounds are eluted from the silicon-containing material into the liquid by containing a hydrophobic colloid that is charged below and the pH of the liquid is in the range of 4 or more and 6 or less, and the zeta potential is positively charged. Therefore, it is possible to prevent silicon and silicon compounds eluted in the liquid from being deposited in the liquid and clogging the flow path and the like.

  Further, according to the present invention, the hydrophobic colloid that is contained to prevent the elution of silicon or silicon compounds from the silicon-containing material into the liquid is deposited on the negatively charged pressure generating element, resulting in kogation. Since this can be prevented, it is possible to prevent the deterioration of the discharge characteristics caused by the occurrence of kogation on the pressure generating element.

  In addition, when the liquid is a recording liquid, kogation on the pressure generating element and elution of silicon and silicon compounds in the liquid can be suppressed, and hydrophobic colloid, silicon, silicon can be used in the liquid, flow path, pressure generating element, etc. Since the precipitation of the compound or the like is prevented, clogging of the flow path and the discharge port can be prevented, and the quality of the image due to the non-discharge of the recording liquid and the deterioration of the discharge characteristics can be prevented.

  Hereinafter, a recording liquid, a liquid cartridge, a liquid discharge cartridge, a liquid discharge apparatus, and a liquid discharge method to which the present invention is applied will be described with reference to an ink jet printer apparatus (hereinafter referred to as a printer apparatus) 1 shown in FIG. . The printer apparatus 1 prints images and characters by ejecting ink or the like onto a recording paper P traveling in a predetermined direction.

  In addition, the printer device 1 is a so-called line in which ink discharge ports (nozzles) are arranged in a substantially line shape in the width direction of the recording paper P, that is, in the direction of the arrow W in FIG. Type printer device.

  As shown in FIGS. 2 and 3, the printer apparatus 1 is an ink jet print head cartridge (hereinafter referred to as a head cartridge) that ejects ink 2 that is a recording liquid for recording images, characters, and the like on a recording paper P. 3) and a printer body 4 to which the head cartridge 3 is mounted.

  The printer apparatus 1 includes an ink cartridge 11y, 11m, which is a liquid cartridge filled with the ink 2, and the head cartridge 3 is detachable from the printer main body 4 and is a supply source of the ink 2 to the head cartridge 3. 11c and 11k are attachable to and detachable from the head cartridge 3.

  In this printer apparatus 1, an ink cartridge 11 y filled with yellow ink 2, an ink cartridge 11 m filled with magenta ink 2, an ink cartridge 11 c filled with cyan ink 2, and a black ink 2 The ink cartridge 11k filled with the ink can be used, the head cartridge 3 can be attached to and detached from the printer body 4, and the ink cartridges 11y, 11m, 11c, and 11k that can be attached to and detached from the head cartridge 3. Can be replaced as a consumable.

  First, the ink 2 that is printed by landing on the recording paper P will be described. The ink 2 is stored in the ink cartridge 11 provided in the head cartridge 3, supplied from the ink cartridge 11 to the ink discharge head 24 described later, and the recording paper P from the nozzles 43 a of the head chips 41 described later provided in the ink discharge head 24. Discharged.

  The ink 2 that becomes a recording liquid when printing is a colorant such as a water-soluble dye that becomes a pigment, various pigments, a solvent that disperses or dissolves the colorant, and an interface for improving the dispersibility of the colorant and the like. When the zeta potential is charged to +10 mV or less when the activator and the normal state, that is, the ink 2 is prepared so as to exhibit weak alkalinity or alkalinity, and when the pH of the ink 2 is in the range of 4 or more and 6 or less, the zeta potential is It is a mixed liquid in which a positively charged hydrophobic colloid is mixed.

  The ink 2 is made weakly alkaline or alkaline in a normal state so that a portion using a metal material or the like of the head chip 41 described later is not oxidized. That is, the hydrophobic colloid contained in the ink 2 is usually charged to +10 mV or less.

  As the colorant, various dyes that are usually used for recording using an ink jet method, such as the following direct dyes, acid dyes, basic dyes, reactive dyes, disperse dyes, vat dyes, and soluble vat dyes are used. be able to.

  Specifically, examples of yellow dyes include C.I. I. Acid Yellow 1, 3, 11, 17, 19, 23, 25, 29, 36, 38, 40, 42, 44, 49, 59, 61, 70, 72, 75, 76, 78, 79, 98, 99, 110, 111, 127, 131, 135, 142, 162, 164, 165, C. I. Direct Yellow 1, 8, 11, 11, 24, 26, 27, 33, 39, 44, 50, 58, 85, 86, 87, 88, 89, 98, 110, 132, 142, 144, C.I. I. Reactive Yellow 1, 2, 3, 4, 6, 7, 11, 12, 13, 14, 15, 15, 16, 17, 18, 22, 23, 24, 25, 26, 27, 37, 42, C.I. I. Food Yellow 3, 4 and the like can be mentioned, and any one or a combination of these may be used.

  Examples of magenta dyes include C.I. I. Acid Red 1, 6, 8, 9, 13, 14, 18, 26, 27, 32, 35, 37, 42, 51, 52, 57, 75, 77, 80, 82, 85, 87, 88, 89, 92, 94, 97, 106, 111, 114, 115, 117, 118, 119, 129, 130, 131, 133, 134, 138, 143, 145, 154, 155, 158, 168, 180, 183, 184, 186 194, 198, 209, 209, 211, 215, 219, 249, 252, 254, 262, 265, 274, 282, 289, 303, 317, 320, 321 and 322, C.I. I. Direct Red 1, 2, 2, 4, 9, 13, 17, 20, 23, 24, 28, 31, 31, 33, 37, 39, 44, the same 46, 62, 63, 75, 79, 80, 81, 83, 84, 89, 95, 99, 113, 197, 201, 218, 220, 224, 225, 226, 227, 228, 229, 230, 321, C.I. I. Reactive Red 1, 2, 3, 4, 4, 6, 7, 8, 11, 11, 12, 13, 16, 17, 17, 19, 20, 21, 21, 23, 24, 28, 29, 31, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41 42, 43, 45, 46, 49, 50, 58, 59, 63, 64, Food Red 7, 9, 14, etc. Any one kind or a plurality of kinds are mixed and used.

  Examples of cyan dyes include C.I. I. Acid Blue 1, 7, 9, 15, 22, 23, 25, 27, 29, 40, 41, 43, 45, 54, 59, 60, 62, 72, 74, 78, 80, 82, 83, 90, 92, 93, 100, 102, 103, 104, 112, 113, 117, 120, 126, 127, 129, 130, 131, 138, 140, 142, 143, 151, 154, 158, 161, 166, 167, 168 170, 171, 182, 183, 183, 184, 187, 192, 199, 203, 204, 205, 229, 234, 236, 249, C.I. I. Direct Blue 1, 2, 6, 15, 25, 41, 71, 76, 77, 78, 80, 86, 87, 90, 98, the same 106, 108, 120, 123, 158, 160, 163, 165, 168, 192, 193, 194, 195, 196, 199, 200, 201, 202, 203, 207, 225, 226, 236, 237, 246, 248, 249, C.I. I. Reactive Blue 1, 2, 2, 3, 4, 7, 7, 9, 13, 13, 15, 15, 17, 18, 19, 20, 20, 21 25, 26, 27, 28, 29, 31, 32, 33, 34, 37, 38, 39, 40, 41, 43, 44, 46 , C.I. I. Food Blue 1, 2 and the like can be mentioned, and any one or a combination of these can be used.

  Examples of black dyes include C.I. I. Acid Black 1, 2, 2, 7, 26, 29, 31, 31, 48, 50, 51, 52, 58, 60, 62, 63, 64, 67, 72, 76, 77, 94, 107, 108, 109, 110, 112, 115, 118, 119, 121, 122, 131, 132, 139, 140, 155, 156, 157, 158, 159, 191; I. Direct Black 17, 19, 22, 32, 38, 51, 56, 62, 71, 74, 75, 77, 94, 105, 106, 107, 108, 112, 113, 117, 118, 132, 133, 146, 154, 168, C.I. I. Reactive Black 1, 3, 3, 4, 5, 8, 9, 10, 10, 12, 13, 14, 18, C.I. I. Food black 2 etc. can be mentioned and any 1 type or multiple types of these are used.

  In the ink 2, the amount of the colorant described above is 0.5% to 15% by weight, and preferably 0.7% to 10% by weight. The concentration of the colorant is determined by such as. In addition, in the ink 2, the lower the colorant concentration, the more the viscosity is adjusted and the reliability when stored for a long time is superior.

  A pigment or the like can also be used as a colorant. However, when a pigment is used as the colorant, there is a possibility that the zeta potential of the hydrophobic colloid described later may be affected. Therefore, a pigment that does not affect the zeta potential of the hydrophobic colloid is used.

  As the solvent for dispersing or dissolving the above-described dye or the like, for example, water satisfying characteristics such as low viscosity, easy handling, low cost, and odorlessness is used. In addition, as the solvent of the ink 2, for example, ion-exchanged water or the like can be used in order to prevent unnecessary ions from being mixed into the ink 2.

  The ink 2 contains a water-soluble organic solvent such as an aliphatic monohydric alcohol, an aliphatic polyhydric alcohol, an aliphatic polyhydric alcohol derivative, or the like as a solvent in addition to a solvent such as water or ion exchange water.

  Specifically, examples of the aliphatic monohydric alcohol include lower alcohols such as methyl alcohol, ethyl alcohol, n-propyl alcohol, i-propyl alcohol, n-butyl alcohol, s-butyl alcohol, and t-butyl alcohol. Any one or a combination of these may be used.

  When the aliphatic monohydric alcohol listed above is used as a solvent, the ink 2 can have an appropriate surface tension, and has excellent penetrability with respect to the recording paper P and the like, dot formation, and drying of printed images. Is obtained. In this case, by using ethyl alcohol, i-propyl alcohol, n-butyl alcohol, or the like among the aliphatic monohydric alcohols as the solvent of the ink 2, the ink 2 having excellent characteristics described above can be obtained.

  Examples of the aliphatic polyhydric alcohol include alkylene glycols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, butylene glycol and glycerol, polyalkylene glycols such as polyethylene glycol and polypropylene glycol, and thiodiglycol. Any one or a combination of these may be used.

  Examples of the aliphatic polyhydric alcohol derivatives include lower alkyl ethers of the above-described aliphatic polyhydric alcohols such as ethylene glycol dimethyl ether, and lower carboxylic acid esters of the above-mentioned aliphatic polyhydric alcohols such as ethylene glycol diacetate. Can be mentioned. When the aliphatic polyhydric alcohols and derivatives thereof listed above are used as the solvent of the ink 2, the ink 2 can be made difficult to dry and the freezing point of the ink 2 can be lowered. In addition, the nozzle 43a can be prevented from being clogged with the dried ink 2.

  Therefore, as a solvent for dispersing the dye or the like, in addition to water, etc., one or more of aliphatic monohydric alcohol, aliphatic polyhydric alcohol, aliphatic polyhydric alcohol derivatives, etc. each having specific properties By mixing and using, the ink 2 suitable for the purpose and application can be obtained.

  The ink 2 includes aliphatic monohydric alcohols, aliphatic polyhydric alcohols and derivatives thereof, amides such as dimethylformamide and dimethylacetamide, ketones such as acetone and diacetone alcohol, and keto alcohols. , Tetrahydrofuran, dioxane, γ-butyllactone, glycerin, 1.2.6-hexanetriol and other trihydric alcohols, diethanolamine, triethanolamine, sulfolane, 2-pyrrolidone, N-methyl-2-pyrrolidone, 1.3 -You may mix and add 1 type or multiple types among nitrogen-containing heterocyclic compounds, such as a dimethyl-2- imidazolidinone. As a result, the ink 2 can improve the above-described characteristics.

  The ink 2 contains a surfactant as a dispersion aid for adjusting the surface tension and dispersing the colorant substantially uniformly. As the surfactant contained in the ink 2, for example, a nonionic surfactant is preferable, but an anionic surfactant or the like can also be used.

  Nonionic surfactants include, for example, polyoxyethylene alkyl ethers, polyoxyethylene alkyl esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene alkyl phenyl ethers, polyoxyethylene alkyl amines, polyoxyethylene alkyl amides, and acetylenes. Examples thereof include glycol-based surfactants, and any one or a combination of these is used.

  In addition to the colorant, solvent, and surfactant described above, the ink 2 is charged in a normal state, that is, when the ink 2 is weakly alkaline or alkaline, the zeta battery is charged to +10 mV or less, and the pH of the ink 2 Also included is a hydrophobic colloid in which the zeta potential is positively charged when is in the range of 4 or more and 6 or less.

  Here, the zeta potential is a portion that effectively acts on the electrokinetic phenomenon, for example, of the potential difference at the interface between the solid and the liquid. Specifically, an electric double layer is formed at the solid-liquid interface, and the potential distribution in the ink 2 is that when the relative movement occurs between the liquid and the solid, the fixing layer moves together with the solid. The potential difference between the pinned layer and the liquid dominates the electrokinetic phenomenon at this time, and this potential difference is called a zeta potential.

  In addition, the hydrophobic colloid here is a sol or the like using water as a dispersion medium. Specifically, the hydrophobic colloid has a low affinity with water and disperses inorganic compounds such as metals, metal sulfides and metal hydroxides. It is a sol as particles.

  Specifically, in the ink 2 in the normal state, the zeta battery is charged to +10 mV or less, and when the pH of the ink 2 is in the range of 4 to 6, the zeta potential is positively charged. Examples thereof include metal oxides such as aluminum and cerium oxide, metal sulfides such as barium sulfate, metal hydroxides such as iron hydroxide, and the like, and any one or a combination of these is used.

  Thus, in the ink 2 containing a predetermined hydrophobic colloid, the pH of the ink 2 is 4 or more even when it comes into contact with the circuit board 42 of the head chip 41 described later formed of a silicon-containing material such as a silicon wafer. Since the hydrophobic colloid, whose zeta potential is positively charged when it falls within the range of 6 or less, adheres to the surface of a silicon-containing material such as a negatively charged silicon wafer, silicon and silicon compounds are more likely to adhere to the silicon-containing material. Elution can be suppressed.

  Specifically, for example, even if the ink 2 normally shows weak alkalinity, the ink 2 shows acidity around a silicon wafer or the like from which silicon or a silicon compound is eluted. Therefore, the pH of the ink 2 is 4 or more, 6 The range is as follows. In this case, the hydrophobic colloid in the ink 2 is positively charged around the silicon wafer, and the positively charged hydrophobic colloid adheres to the negatively charged silicon wafer. As described above, the elution of silicon and silicon compounds is suppressed.

Here, in FIG. 4, the above-described aluminum oxide (Al ₂ O ₃ ) and cerium oxide (CeO) as hydrophobic colloids in which the zeta potential is positively charged when the pH of the ink 2 is in the range of 4 or more and 6 or less. ), Barium sulfate (BaSO ₄ ), and silica (SiO ₂ ) as an example of a hydrophobic colloid that is difficult to suppress the elution of silicon and silicon compounds from silicon-containing materials. The characteristic view which shows the relationship between the zeta potential when making it disperse | distribute in a dispersion medium and pH of a dispersion medium is shown.

  From the results shown in FIG. 4, it can be seen that aluminum oxide, cerium oxide, and barium sulfate are positively charged with a zeta potential when the pH of the dispersion medium is 6 or less. It can also be seen that silica is not positively charged with a zeta potential when the pH of the dispersion medium is 4 or more and 6 or less.

  Therefore, in silica, for example, elution of silicon or the like starts from a silicon wafer exposed to the weakly alkaline ink 2, and the silicon wafer that is negatively charged even if the ink 2 becomes acidic around the silicon wafer. The silicon and silicon compound continue to elute from the silicon wafer and it becomes difficult to suppress the elution of silicon and silicon compound from the silicon wafer.

  On the other hand, in aluminum oxide, cerium oxide, and barium sulfate, for example, when elution of silicon or the like starts from a silicon wafer exposed to the weakly alkaline ink 2, the ink 2 becomes acidic around the silicon wafer. In addition, since the zeta potential is appropriately positively charged around the silicon wafer, it appropriately adheres to the negatively charged silicon wafer and appropriately suppresses the elution of silicon and silicon compounds from the silicon wafer.

  In addition, the hydrophobic colloid is charged to a zeta potential of +10 mV or less when the ink 2 is in a normal state, that is, when the ink 2 is weakly alkaline or alkaline. Specifically, in the ink 2, the pH is adjusted using a pH adjusting agent or the like, which will be described later, so that the hydrophobic colloid is charged at a zeta potential of +10 mV or less.

  That is, in ink 2, as can be seen from FIG. 4, when aluminum oxide is used as the hydrophobic colloid, the pH is greater than 8.5, and when cerium oxide is used as the hydrophobic colloid, the pH is greater than 7. When barium sulfate is used as the hydrophobic colloid, the hydrophobic colloid can be charged at a zeta potential of +10 mV or less by adjusting the pH with a pH adjusting agent or the like so that the pH is higher than 6.

  As a result, in the ink 2, for example, even if a heating resistor 46 (described later) that generates pressure for discharging from the nozzle 43a is negatively charged, the hydrophobic colloid adheres to the negatively charged heating resistor 46 and precipitates. It is possible to prevent the occurrence of kogation mainly composed of a hydrophobic colloid on the heating resistor 46. Therefore, in the ink 2, it is possible to suppress the deterioration of the ejection characteristics caused by the occurrence of kogation in the heating resistor 46 described later.

  The above-described hydrophobic colloid contained in the ink 2 is contained in the ink 2 in the range of 3 ppm to 10000 ppm, more preferably in the range of 10 ppm to 1000 ppm. When the content of the hydrophobic colloid relative to the ink 2 is less than 3 ppm, the content of the hydrophobic colloid is too low, and the silicon-containing material such as a silicon wafer is exposed to the ink 2 exhibiting weak alkalinity. It becomes difficult to suppress the elution of silicon and silicon compounds from the material.

  In the ink 2, in addition to the above-described colorant, solvent, surfactant, and predetermined hydrophobic colloid, for example, a viscosity adjuster, a surface tension adjuster, a pH adjuster, an antiseptic, an antifungal agent, and the like are added. You can also.

  Examples of viscosity modifiers and surface tension modifiers include proteins such as gelatin and casein, natural rubbers such as gum arabic, cellulose derivatives such as methylcellulose and carboxymethylcellulose, natural polymers such as lignin sulfonate and shellac, and polyallylates. , Styrene-acrylic acid copolymer salt, polyvinyl alcohol, polyvinyl pyrrolidone and the like, and any one or a combination of these may be used.

  Examples of the pH adjusting agent include alkali metal hydroxides or amines such as lithium hydroxide, sodium hydroxide, potassium hydroxide, triethanolamine, diethanolamine, and aminomethylpropanol. In the ink 2, the pH is prepared using the above-described pH adjusting agent so that the hydrophobic colloid is charged at a zeta potential of +10 mV or less.

  Examples of antiseptics and fungicides include sodium benzoate, sodium pentachlorophenol, sodium 2-pyridinethiol-1-oxide, sodium sorbate, sodium dehydroacetate, and 1,2-dibenzothiazoline-3- ON (product names Proxel CRL, Proxel BND, Proxel GXL, Proxel XL-2, Proxel TN) and the like are used, and any one or a combination of these is used.

  The ink 2 having the above configuration is prepared as follows. When preparing a dissolving ink 2 using a dye or the like as a colorant, the ink 2 is prepared by mixing a colorant composed of the above-described dye, a solvent, a surfactant, and a predetermined hydrophobic colloid. It is obtained by stirring and dispersing with a screw or the like while heating at -80 ° C. Then, the obtained ink 2 is adjusted for pH by appropriately adding a pH adjusting agent or the like so that the hydrophobic colloid is charged at a zeta potential of +10 mV or less as necessary.

  In addition, in the case of the dispersion type ink 2 using a pigment or the like as a colorant, conventionally used pigment fine dispersion methods such as ball mill, sand mill, attritor, roll mill, agitator, Henshur mixer, colloid mill, ultrasonic wave Using a dispersing device such as a homogenizer, a pearl mill, a wet jet mill, etc., the pigment is, for example, sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium carbonate, sodium hydrogen carbonate, aqueous ammonia, trietamine amine, diethanolamine, triethylamine, It can be prepared by dispersing together with the above-mentioned predetermined hydrophobic colloid in water made alkaline with aminomethylpropanol or the like. Also in this case, if necessary, the pH is adjusted with a pH adjusting agent or the like so that the hydrophobic colloid has a pH charged at a zeta potential of +10 mV or less.

  The ink 2 thus prepared is subjected to at least one pressure filtration treatment or vacuum filtration treatment using a filter, for example, in order to remove dust, coarse particles, and mixed materials, or a centrifuge. Etc., the centrifugal separation treatment is performed at least once or a combination thereof.

  When the ink 2 is prepared in this way, in order to cope with high-speed printing, specifically, a heating resistor 46 described later is provided with a pulse current having a frequency of 1 kHz or more, preferably 3 kHz or more, more preferably 5 kHz or more. In order to enable driving, the surface tension of ink 2 at 25 ° C. is adjusted to 30 to 60 mN / m, more preferably 30 to 40 mN / m. Further, the ink 2 is adjusted so as to be a low viscosity type having a viscosity of preferably 15 mPa · s or less, more preferably 5 mPa · s or less.

  As shown in FIGS. 2 and 3, the ink 2 described above is filled with the ink cartridge 11y in the yellow, the ink cartridge 11m in the magenta, and the ink in the cyan. A cartridge that fills the cartridge 11c and exhibits black is filled into the ink cartridge 11k.

  Next, referring to the drawings, the head cartridge 3 that can be attached to and detached from the printer main body 4 constituting the printer apparatus 1 and the ink cartridges 11y, 11m, 11c, and 11k that can be attached to and detached from the head cartridge 3 will be described. I will explain.

  As shown in FIG. 1, the head cartridge 3 that prints on the recording paper P is mounted on the recording paper P that is mounted from the upper surface side of the printer body 4, that is, from the direction of arrow A in FIG. On the other hand, printing is performed by ejecting ink 2.

  The head cartridge 3 discharges the ink 2 described above into fine particles by the pressure generated by the pressure generating means using, for example, an electrothermal conversion type or an electromechanical conversion type. The ink 2 in a droplet state is ejected toward the surface. Here, the case where the ink 2 is ejected in a droplet state using an electric heat exchange type as the pressure generating means will be described as an example.

  As shown in FIGS. 2 and 3, the head cartridge 3 includes a cartridge main body 21, and ink cartridges 11 y, 11 m, 11 c, and 11 k that are containers filled with the ink 2 are attached to the cartridge main body 21. The Hereinafter, the ink cartridges 11y, 11m, 11c, and 11k are also simply referred to as the ink cartridge 11.

  The ink cartridge 11 that can be attached to and detached from the head cartridge 3 includes an ink filling unit 12 filled with the ink 2, an ink supply unit 13 that supplies the ink 2 from the ink filling unit 12 to the cartridge body 21 of the head cartridge 3, and an external device. An external communication hole 14 for taking air into the ink filling part 12, an air introduction path 15 for introducing the air taken in from the external communication hole 14 into the ink filling part 12, and the external communication hole 14 and the air introduction path 15. And a storage section 16 for temporarily storing the ink 2 therebetween. The ink cartridge 11 is formed by, for example, injection molding a resin material such as polypropylene having strength and ink resistance, and has a substantially rectangular shape whose longitudinal direction is substantially the same as the width direction of the recording paper P. Thus, the ink capacity stored inside is maximized.

  The ink filling part 12 is a space part in which the ink 2 is filled with a highly airtight material. The ink filling unit 12 is formed in a substantially rectangular shape, and its longitudinal dimension is substantially the same as the width direction of the recording paper P used, that is, the width direction W of the recording paper P shown in FIG. Is formed.

  The ink supply unit 13 is provided in a substantially central portion below the ink filling unit 12. The ink supply unit 13 is a substantially protruding nozzle that communicates with the ink filling unit 12, and the tip of the nozzle is fitted into a connection unit 23 of the head cartridge 3 described later, whereby the ink cartridge 11 and the head cartridge are connected. 3 cartridge body 21 is connected. The ink 2 is supplied from the ink cartridge 11 filled with ink to the cartridge body 21 via the ink supply unit 13.

  As shown in FIG. 3, the external communication hole 14 is a vent for taking in air from the outside of the ink cartridge 11 to the ink filling unit 12, and even when mounted on the mounting unit 22 of the head cartridge 3, the external communication hole 14 is exposed to the outside. In order to be able to take in, it is provided on the upper surface of the ink cartridge 11, which is the position facing the outside when mounted on the mounting portion 22, here, in the vicinity of the substantially upper central portion here.

  The external communication hole 14 corresponds to a decrease in the ink 2 in the ink filling unit 12 when the ink cartridge 11 is mounted on the cartridge main body 21 and the ink 2 flows down from the ink filling unit 12 to the cartridge main body 21 side. Minute air is taken into the ink cartridge 11 from the outside.

  The air introduction path 15 communicates the ink filling part 12 and the external communication hole 14, and introduces air taken in from the external communication hole 14 into the ink filling part 12.

  Thus, when the ink cartridge 11 is mounted on the cartridge main body 21, the ink 2 is supplied to the cartridge main body 21 of the head cartridge 3, the ink 2 in the ink filling unit 12 is reduced, and the inside is in a decompressed state. In addition, since air is introduced into the ink filling unit 12 through the air introduction path 15 in the ink filling unit 12, the internal pressure is maintained in an equilibrium state, and the ink 2 can be appropriately supplied to the cartridge body 21. it can.

  The storage section 16 is provided between the external communication hole 14 and the air introduction path 15, and when the ink 2 leaks from the air introduction path 15 communicating with the ink filling section 12, it does not suddenly flow out to the outside. Thus, the ink 2 is temporarily stored.

  The storage portion 16 is formed in a substantially rhombus with the longer diagonal line in the longitudinal direction of the ink filling portion 12, and is located at the top of the lowermost portion of the ink filling portion 12, that is, on the lower side of the shorter diagonal line. An air introduction path 15 is provided so that the ink 2 that has entered from the ink filling unit 12 can be returned to the ink filling unit 12 again. Further, the reservoir 16 is provided with an external communication hole 14 at the lowest top on the shorter diagonal line so that the ink 2 that has entered from the ink filling unit 12 is less likely to leak to the outside through the external communication hole 14.

  In addition to the above-described configuration, the ink cartridge 11 configured as described above includes, for example, a remaining amount detection unit for detecting the remaining amount of the ink 2 in the ink filling unit 12, and the ink cartridges 11y, 11m, 11c, and 11k. And an identification unit for identifying.

  Next, the head cartridge 3 to which the ink cartridges 11y, 11m, 11c, and 11k containing the yellow, magenta, cyan, and black inks 2 configured as described above are mounted will be described.

  As shown in FIGS. 2 and 3, the head cartridge 3 includes the ink cartridge 11 and the cartridge main body 21 described above. The cartridge main body 21 has mounting portions 22y, 22m, 22c, to which the ink cartridge 11 is mounted. 22k (hereinafter, also simply referred to as a mounting portion 22), a connection portion 23 connected to the ink supply portion 13 and supplied with the ink 2, and the ink 2 being ejected in the state of an ink droplet i. An ink discharge head 24 and a head cap 25 that protects the ink discharge head 24 are provided.

  The mounting portion 22 to which the ink cartridge 11 is mounted is formed in a substantially concave shape with the upper surface as an insertion / removal opening of the ink cartridge 11 so that the ink cartridge 11 is mounted. Here, four ink cartridges 11 are formed on the recording paper P. They are stored side by side in a direction substantially perpendicular to the width direction, that is, in the running direction of the recording paper P. Since the ink cartridge 11 is accommodated in the mounting portion 22, the mounting portion 22 is provided long in the direction of the printing width in the same manner as the ink cartridge 11. The ink cartridge 11 is housed in the cartridge body 21.

  As shown in FIG. 2, the mounting portion 22 is a portion where the ink cartridge 11 is mounted. The portion where the yellow ink cartridge 11y is mounted is the mounting portion 22y, and the magenta ink cartridge 11m is mounted. The portion is the mounting portion 22m, the portion where the cyan ink cartridge 11c is mounted is the mounting portion 22c, the portion where the black ink cartridge 11k is mounted is the mounting portion 22k, and each mounting portion 22y, 22m, 22c, Each of 22k is partitioned by a partition wall 22a.

  The ink cartridges 11y, 11m, 11c, and 11k are mounted on the mounting portions 22y, 22m, 22c, and 22k at the center in the longitudinal direction of the mounting portions 22y, 22m, 22c, and 22k. , 11c, and 11k are provided with connection portions 23 to which the ink supply portions 13 are connected.

  The connection portion 23 is an ink supply path that supplies the ink 2 to the ink discharge head 24 that discharges the ink 2 provided on the bottom surface of the cartridge main body 21 from the ink supply portion 13 of the ink cartridge 11 attached to the attachment portion 22. Become.

  Specifically, as shown in FIG. 5, the connection portion 23 includes an ink reservoir portion 23 a that stores the ink 2 supplied from the ink cartridge 11 and a seal member 23 b that seals the ink supply portion 13 connected to the connection portion 23. And a filter 23c for removing impurities in the ink 2 and a valve mechanism 23d for opening and closing the supply path to the ink discharge head 24 side.

  The ink reservoir 23 a is a space that is connected to the ink supply unit 13 and stores the ink 2 supplied from the ink cartridge 11.

  The seal member 23b is a member provided at the upper end of the ink reservoir 23a. When the ink supply part 13 of the ink cartridge 11 is connected to the ink reservoir 23a of the connection part 23, the ink 2 does not leak to the outside. The space between the ink reservoir 23a and the ink supply unit 13 is sealed.

  The filter 23c removes dust such as dust and dirt mixed in the ink 2 when the ink cartridge 11 is attached and detached, and is provided downstream of the ink reservoir 23a.

  The valve mechanism 23d opens when the ink 2 is discharged from the ink discharge head 24 and the pressure of the ink 2 in the ink discharge head 24 is reduced, and the ink 2 is supplied from the ink cartridge 11 to the ink discharge head 24 side. The pressure of the ink 2 in the ink discharge head 24 is kept substantially constant. Then, when the ink 2 is supplied from the ink cartridge 11 side to the ink ejection head 24 side and the pressure of the ink 2 in the ink ejection head 24 becomes substantially constant, the ink 2 is closed, and further from the ink cartridge 11 to the ink ejection head 24 side. So that the ink 2 is not supplied.

  Further, in the connection portion 23 having such a configuration, when the ink 2 in the ink cartridge 11 is supplied to the ink discharge head 24, the ink 2 in the ink filling portion 12 decreases. From outside enters the ink cartridge 11. The air that has entered the ink cartridge 11 is sent above the ink cartridge 11. As a result, the ink droplet i returns to a state before being ejected from a nozzle 43a, which will be described later, and is in an equilibrium state. At this time, an equilibrium state is reached with almost no ink 2 in the air introduction path 15.

  The ink discharge head 24 is disposed along the bottom surface of the cartridge main body 21, and a nozzle 43 a, which will be described later, is an ink discharge port that discharges the ink 2 supplied from the connection portion 23 in the state of the ink droplet i. For each color, the recording paper P is arranged in a substantially straight line in the width direction of the recording paper P, that is, in the direction of the arrow W in FIG.

  As shown in FIG. 2, the head cap 25 is a cover provided to protect the ink discharge head 24, and is retracted from the ink discharge head 24 during a printing operation. The head cap 25 is provided with a pair of engaging protrusions 25a provided in the opening / closing direction at both ends in the direction of arrow W in FIG. 2 and excess ink 2 attached to the ejection surface 24a of the ink ejection head 24 provided in the longitudinal direction. And a cleaning roller 25b for sucking.

  The head cap 25 is engaged with a pair of engagement grooves 25b in which the engagement protrusion 25a is provided on the discharge surface 24a of the ink discharge head 24 in a direction substantially orthogonal to the arrow W direction in FIG. The ink cartridge 11 is opened and closed in a direction substantially perpendicular to the short direction of the ink cartridge 11, that is, the arrow W direction in FIG. 2, along the pair of engaging grooves 25b.

  In the head cap 25, during the opening / closing operation, the cleaning roller 25 b rotates while contacting the ejection surface 24 a of the ink ejection head 24, so that excess ink 2 is sucked and the ejection surface 24 a of the ink ejection head 24 is cleaned. To do. For the cleaning roller 25b, for example, a highly hygroscopic member, specifically, a sponge, a nonwoven fabric, a woven fabric, or the like is used. The head cap 25 closes the ejection surface 24a so that the ink 2 in the ink ejection head 24 is not dried when the printing operation is not performed.

  As shown in FIG. 5, the ink discharge head 24 is positioned above the discharge surface 24 a, the ink supply port 31 to which the ink 2 is supplied from the ink supply unit 13, and the supply from the ink supply port 31. And an ink flow path 32 for guiding the ink 2 to the nozzles 43a.

  The ink supply port 31 is provided at the center of the upper surface of the ink flow path 32 and communicates with the valve mechanism 23d described above.

  The ink flow path 32 is provided so as to be substantially linear over a length corresponding to the width of the recording paper so that the ink 2 is supplied to each color nozzle 43a described later.

  In the ink discharge head 24, head chips 41 each having a predetermined number of nozzles 43a, which will be described later, are arranged in a staggered manner for each color. That is, as shown in FIG. 6, the head chips 41 are arranged so as to be alternately arranged in the width direction of the recording paper P across the ink flow path 32 for each color.

  As shown in FIG. 7, the head chip 41 divides the circuit board 42 as a base, the nozzle sheet 43 formed with a plurality of nozzles 43a, and the circuit board 42 and the nozzle sheet 43 for each nozzle 43a. It has a film 44, an ink liquid chamber 45 that pressurizes the ink 2 supplied through the ink flow path 32, and a heating resistor 46 that heats the ink 2 supplied to the ink liquid chamber 45.

  The circuit board 42 is formed with a control circuit made up of a logic IC (Integrated Circuit), a driver transistor, etc. on a board made of a silicon-containing material or the like such as a silicon wafer or a glass substrate, and an upper surface portion of the ink liquid chamber 45. In addition, the edge side surface 42 a forms part of the ink flow path 32. That is, the circuit board 42 is a semiconductor circuit board or the like.

  The nozzle sheet 43 is formed with a nozzle 43a having a reduced diameter toward the ejection surface 24a, and is disposed to face the circuit board 42 and the film 44 so as to form a lower surface portion of the ink liquid chamber 45. ing.

  The film 44 is made of, for example, an exposure curable dry film resist, and is formed so as to surround each nozzle 43a except for the portion communicating with the ink flow path 32 described above. Further, the film 44 is interposed between the circuit board 42 and the nozzle sheet 43, thereby forming a side surface portion of the ink liquid chamber 45.

  The ink liquid chamber 45 is surrounded by the circuit board 42, the nozzle sheet 43, and the film 44 described above, thereby forming a pressurizing space that pressurizes the ink 2 supplied from the ink flow path 32 for each nozzle 43a.

  The heating resistor 46 is disposed on the circuit board 42 facing the ink liquid chamber 45 and is electrically connected to the control circuit of the circuit board 42. Specifically, the heating resistor 46 is formed by patterning a resistor film having a thickness of about 80 nm to 200 nm made of tantalum or the like electrically connected to the control circuit on the circuit board 42 into a predetermined shape. Further, it is made of a silicon nitride film or the like, and is made of an insulating protective film having a thickness of about several tens to several hundreds of nanometers for protecting and insulating the resistor film, and β-tantalum or the like, and has a thickness of 10 minutes for protecting the heating resistor 46 from cavitation or the like. And a cavitation-resistant film having a thickness of about several nm to several nm are sequentially stacked.

  Note that cavitation refers to foaming and extinction in which the heating resistor 46 heats the ink 2 and bubbles are generated in the ink 2, and the ink droplets i are ejected from the nozzles 43 a by pressing the generated bubbles and the bubbles disappear. This refers to a mechanical impact that the heating resistor 46 receives each time the bubble is repeated. Β-tantalum serving as a cavitation-resistant layer has a tetragonal structure and is an excellent material that can appropriately mitigate mechanical shock due to cavitation that the heating resistor 46 receives.

  In the heating resistor 46 having such a configuration, the resistor film to which the pulse current is supplied is heated by the control of the control circuit or the like, and the ink 2 in the ink liquid chamber 45 is heated.

  The heating resistor 46 may be negatively charged under the influence of a pulse current flowing through a control circuit or the like formed on the circuit board 42. For this reason, in the ink 2, as described above, the hydrophobic colloid is charged at a zeta potential of +10 mV or lower in a normal state, and the negatively charged heating resistor 46 is prevented from adhering to the hydrophobic colloid. . Thereby, in the heat generating resistor 46, it is suppressed that a hydrophobic colloid adheres to the surface and it becomes a kogation, and the ink 2 can be heated appropriately.

  For measuring the surface potential of the resistance heating element 46, a measuring device capable of measuring the potential of the surface of the anti-cavitation layer that is the surface thereof is used. Specifically, examples of the measuring instrument for measuring the surface potential of the resistance heating element 46 include a probe microscope, preferably a scanning probe microscope (AutoprobeCP) manufactured by PSI using the Kelvin method. KFM measurements were performed by adding the EFM / SCM option to the scanning probe microscope.

  Here, the KFM measurement is a measurement sample so as to cancel the electrostatic force (attraction) between induced charges induced on both poles of a capacitor composed of a grounded conductive probe (cantilever) and the sample surface. An offset voltage is applied to and the sample potential is obtained from the value.

  The KFM measurement has the same basic configuration as the EFM (Electro-static Force Microscope) measurement in which the electrostatic force is measured by applying DC and AC voltages to the conductive probe of the non-contact mode AFM, but the DC voltage is the same. It is characterized in that a feedback circuit is added.

  In the head chip 41 configured as described above, the control circuit of the circuit board 42 controls the pulse current supplied to the heating resistor 46, and for example 1 to 3 microseconds for the selected heating resistor 46. A pulse current is supplied only for a certain degree.

  Thereby, the heating resistor 46 is rapidly heated. As a result, bubbles are generated in the ink 2 in the ink liquid chamber 45 in contact with the heating resistor 46. Then, in the in-pressurization chamber 47, the ink 2 is pressurized while the bubbles expand, and the ejected ink 2 droplets are ejected from the nozzle 43a. Further, after the ink 2 droplets are ejected, the ink 2 is supplied to the ink liquid chamber 45 through the ink flow path 32, thereby returning to the state before ejection again.

  Specifically, when the ink 2 is rapidly heated by the heating resistor 46, the temperature of the ink 2 rapidly exceeds the boiling point. Then, when the ink temperature is heated to about 300 ° C. and reaches the spontaneous nucleation temperature, an infinite number of ink bubbles b are instantaneously generated on the heating resistor 46. Then, in the ink liquid chamber 45, as shown in FIG. 8, excess energy in the ink 2 is released at once, and the internal pressure of the ink bubble b rises.

  The ink bubbles b grow rapidly. Then, as shown in FIG. 9, the ink 2 in the ink liquid chamber 45 jumps out of the nozzle 43a with the momentum of the growth of the ink bubble b, and the ink bubble b is depressurized and contracts with the expansion. The ink 2 that has ejected from the nozzle 43a has its tail extended outside the nozzle 43a due to its inertia and the contraction of the ink bubbles b, that is, the ink 2 is ejected from the nozzle 43a in the state of an ink droplet i.

  The ink bubbles b in the ink liquid chamber 45 collapse on the heating resistor 46. In the nozzle 43 a, a capillary force that tries to return to the original meniscus (the liquid level of the nozzle 43 a) works, and the same amount of ink 2 is discharged from the ink flow path 32 through the ink liquid chamber 45. Supplied. Thus, in the head chip 41, the ink droplet i is discharged from the nozzle 43a.

  In the head chip 41 described above, the film 44 is formed over the entire main surface of the circuit board 42, and the film 44 is formed into a shape corresponding to the ink liquid chamber 45 by using a photolithography technique. It is formed by laminating a nozzle sheet 43 thereon. Further, the above-described head chip 41 employs an electrothermal conversion method in which the ink 2 is ejected while being heated by the heating resistor 46, but is not limited to such a method, for example, an electromechanical conversion such as a piezoelectric element. An electromechanical conversion method in which droplets of ink 2 are ejected electromechanically by an element may be employed.

  An ink discharge head 24 is provided below the ink supply unit 13 corresponding to each color described above. The bottom surface of the cartridge main body 21 is provided with discharge surfaces 24a of the ink discharge heads 24 of the respective colors side by side in the short direction of the cartridge main body 21, and these form a continuous discharge surface 24a. .

  That is, the head cartridge 3 has a so-called multi-line head in which the ink discharge heads 24 corresponding to the respective colors are integrated to form a continuous discharge surface 24a. The ink discharge head 24 is provided with about 100 to 5000 nozzles 43a for each color, and the entire discharge surface 24a is provided with about 400 to 20000 nozzles 43a. In addition, in the ink discharge head 24, it is possible to perform high-speed discharge in which the ink 2 is discharged from the nozzles 43a about every 1/7000 second.

  In the ink ejection head 24 configured as described above, in the head chip 41, the main surface of the circuit board 42 on which the heating resistor 46 and the like are provided can be easily subjected to a surface treatment such as an oxidation treatment. Even if the main surface of the circuit board 42 is exposed to the alkaline ink 2 by such surface treatment, silicon or the like does not elute from the circuit board 42, but the circuit board constituting a part of the ink flow path 32. Since the silicon-containing material such as a silicon wafer cut out by dicing or the like is exposed to the ink 2 on the edge side surface 42a or the like of the edge 42, the edge of the circuit board 42 exposed to the ink 2 showing alkalinity is exposed. There is a possibility that silicon, a silicon compound, or the like may elute into the ink 2 from the side surface 42a.

  However, in this head chip 41, as shown in FIG. 10, since the ink 2 contains a hydrophobic colloid in which the zeta potential is positively charged when the pH is in the range of 4 or more and 6 or less, For example, when elution of silicon or the like starts from the edge side surface 42a of the circuit board 42 exposed to the weakly alkaline ink 2 and the ink 2 becomes acidic around the circuit board 42, the periphery of the circuit board 42 The zeta potential of the hydrophobic colloid contained in the ink 2 is positively charged.

  As a result, in the head chip 41, the hydrophobic colloid having a positively charged zeta potential adheres to the negatively charged portion of the circuit board 42 where the silicon-containing material is exposed, that is, the edge side surface 42a of the circuit board 42. The elution of silicon and silicon compounds from the circuit board 42 is suppressed. In FIG. 10, a positively charged hydrophobic colloid is indicated by C.

  Therefore, in the head chip 41, even if the ink 2 showing alkalinity is left in the ink flow path 32, the ink liquid chamber 45, etc. for a long period of time, silicon or the like is eluted from the circuit board 42 without being eluted. So-called kogation in which silicon or a silicon compound is deposited on the heating resistor 46 can be prevented. Further, clogging caused by precipitation of silicon or silicon compound eluted from the circuit board in the nozzle 43a or the ink flow path 32 can be prevented.

  That is, in the head cartridge 3 described above, for example, when ink 2 showing alkalinity is ejected from the ink ejection head 24, kogation made of a silicon compound or the like occurs on the heating resistor 46, or in the ink 2. Since it is possible to prevent silicon and silicon compounds from being deposited and clogging the nozzles 43a, it is possible to prevent deterioration in ejection characteristics and non-ejection of ink.

  Further, in the head cartridge 3, since the hydrophobic colloid contained in order to prevent elution of silicon or the like is suppressed from being kogated on the heating resistor 46 as described above, the discharge characteristics are deteriorated. Can be prevented.

  Next, the printer main body 4 constituting the printer apparatus 1 to which the head cartridge 3 described above is mounted will be described with reference to the drawings.

  As shown in FIGS. 1 and 11, the printer main body 4 includes a head cartridge mounting portion 51 to which the head cartridge 3 is mounted, and a head cartridge holding mechanism 52 for holding and fixing the head cartridge 3 to the head cartridge mounting portion 51. A head cap opening / closing mechanism 53 for opening / closing the head cap, a paper supply / discharge mechanism 54 for supplying / discharging the recording paper P, a paper feed port 55 for supplying the recording paper P to the paper supply / discharge mechanism 54, and a paper supply / discharge And a paper discharge port 56 from which the recording paper P is output from the mechanism 54.

  The head cartridge mounting portion 51 is a recess in which the head cartridge 3 is mounted, and performs printing according to data on the traveling recording paper P, so that the ejection surface 24a of the ink ejection head 24 and the paper surface of the traveling recording paper P are mutually connected. The head cartridge 3 is mounted so as to be substantially parallel.

  The head cartridge 3 may need to be replaced due to ink clogging or the like in the ink ejection head 24. The head cartridge 3 is a consumable item that is not as frequent as the ink cartridge 11, but the head cartridge 3 is not used. The head cartridge holding mechanism 52 is detachably held.

  The head cartridge holding mechanism 52 is a mechanism for detachably holding the head cartridge 3 on the head cartridge mounting portion 51, and a knob 52 a provided on the head cartridge 3 is provided in the locking hole 52 b of the printer main body 4. The head cartridge 3 can be positioned, held and fixed by being pressed against a reference surface 4a provided in the printer main body 4 by being engaged with a biasing member such as a spring (not shown).

  The head cap opening / closing mechanism 53 has a drive unit that opens and closes the head cap 25 of the head cartridge 3. When performing printing, the head cap 25 is opened and the discharge surface 24 a of the ink discharge head 24 is placed on the recording paper P. The head cap 25 is closed when printing is finished to protect the ink discharge head 24.

  The paper supply / discharge mechanism 54 has a drive unit for transporting the recording paper P, transports the recording paper P supplied from the paper feed port 55 to the ink ejection head 24 of the head cartridge 3, and is ejected from the nozzle 43a. The ink droplet i has landed, and the printed recording paper P is conveyed to the paper discharge port 56 and discharged outside the apparatus.

  The paper supply port 55 is an opening for supplying the recording paper P to the paper supply / discharge mechanism 54, and a plurality of recording papers P can be stacked and stocked on the tray 55a or the like. The paper discharge port 56 is an opening through which ink droplets i land and discharge the printed recording paper P.

  Next, the printing operation of the printer apparatus 1 configured as described above will be described. This operation is executed by arithmetic processing of a CPU (Central Processing Unit) (not shown) based on a processing program stored in a storage means such as a ROM (Read Only Memory) (not shown) provided in the apparatus. It is.

  First, the user operates an operation button or the like provided on the printer body 4 to instruct the printer device 1 to execute a printing operation.

  When performing the printing operation, the drive mechanisms 53 and 54 are driven to move the recording paper P to a printable position. Specifically, as shown in FIG. 12, a drive motor or the like constituting the head cap opening / closing mechanism 53 is driven to move the head cap 25 to the front side of the printer apparatus 1, that is, the tray 55a side with respect to the head cartridge 3. The nozzle 43a of the ink discharge head 24 is exposed.

  Further, the paper supply / discharge mechanism 54 drives a drive motor (not shown) to convey the recording paper P. Specifically, in the paper feeding / discharging mechanism 54, as shown in FIG. 12, the recording paper P is pulled out from the tray 55a by the paper feeding roller 61 and pulled out by a pair of separation rollers 62a and 62b rotating in the same direction. After one sheet of P is conveyed to the reverse roller 63 and the conveying direction is reversed, the recording paper P is conveyed to the conveying belt 64, and the platen plate 65 holds the recording paper P conveyed to the conveying belt 64 at a predetermined position. Let In this way, the paper supply / discharge mechanism 54 transports the recording paper P to the position where the ink 2 is landed.

  Next, the recording paper P conveyed to the printing position is discharged at a predetermined interval from each nozzle 43a of the ink discharge head 24 by supplying a pulse current to the heating resistor 46 of the head chip 41 at a predetermined interval. The ink droplet i thus formed is landed, and an image, characters, and the like composed of ink dots are recorded.

  At this time, in the ink discharge head 24, the zeta potential is charged to +10 mV or less when the pH of the ink 2 is weakly alkaline or alkaline in the ink 2 accommodated in the ink flow path 32, the ink liquid chamber 45, or the like. Since the hydrophobic colloid is contained, for example, even if the heating resistor 46 of the head chip 41 is negatively charged, the hydrophobic colloid may adhere to the negatively charged heating resistor 46 and become kogation. Therefore, it is possible to prevent deterioration of the discharge characteristics.

  In addition, in the ink ejection head 24, since the ink 2 contains a hydrophobic colloid in which the zeta potential is positively charged when the pH of the ink 2 becomes 4 to 6, the ink 2 is made of, for example, a silicon wafer. Even when the circuit board 42 constituting the ink flow path 32 and the ink liquid chamber 45 is exposed to the ink 2, specifically, the edge side surface 42 a of the circuit board 42 is exposed to silicon or a silicon compound in the ink 2 from the circuit board 42. And the like can be prevented from eluting.

  That is, in the ink ejection head 24, the hydrophobic colloid around the circuit board 41 adheres to the circuit board 41 that is negatively charged due to the zeta potential being positively charged due to the acidity of the ink 2. On the other hand, the hydrophobic colloid other than the periphery of the circuit board 41 suppresses elution of silicon or the like, and the ink 2 exhibits weak alkalinity, so that the zeta potential is charged to +10 mV or less and is negatively charged. Suppresses adhesion.

  Therefore, in this ink discharge head 24, the elution of silicon and silicon compounds from the circuit board 42 into the ink 2 is suppressed, and the adhesion of the hydrophobic colloid to the heating resistor 46 is suppressed. Silicon and silicon compounds eluted in the ink 2 and hydrophobic colloids contained in the ink are deposited on the heating resistor 46 to cause kogation, or deposited in the ink flow path 32 and the nozzle 43a. Therefore, it is possible to prevent non-ejection and deterioration of ejection characteristics caused by clogging.

  In this way, ink droplets i are appropriately ejected and landed on the recording paper P running by the paper supply / discharge mechanism 54, and characters and images corresponding to the print data are printed with excellent image quality. become. Then, the recording paper P that has been printed is transported to the paper discharge port 56 by the paper supply / discharge mechanism 54 and discharged.

  In the printer apparatus 1 described above, when the ink 2 is in a normal state, that is, when the pH of the ink 2 is weakly alkaline or alkaline, the zeta potential of the hydrophobic colloid is charged to +10 mV or less. For example, even if the heating resistor 46 of the head chip 41 is negatively charged, the hydrophobic colloid is prevented from adhering to the negatively charged heating resistor 46 and causing kogation mainly composed of the hydrophobic colloid. Thus, it is possible to prevent deterioration of the discharge characteristics.

  Further, in this printer apparatus 1, since the ink 2 contains a hydrophobic colloid in which the zeta potential is positively charged when the pH of the ink 2 becomes 4 to 6, a silicon-containing material such as a silicon wafer is used. Even if the circuit board 42 made of is exposed to the ink 2, it is possible to suppress the elution of silicon, silicon compounds, and the like from the circuit board 42 into the ink 2.

  As a result, in this printer apparatus 1, silicon, silicon compounds, and the like that are eluted from the circuit board 42 into the ink 2 are suppressed. It is possible to prevent non-ejection and deterioration of ejection characteristics caused by depositing on the body 46 to cause kogation, or depositing in the ink flow path 32 and the nozzle 43a and causing clogging.

  Therefore, in this printer apparatus 1, the occurrence of kogation made of a hydrophobic colloid, a silicon compound, or the like on the heating resistor 46 or clogging of the nozzle 43a is prevented, and the ink droplet i is appropriately discharged from the nozzle 43a. Therefore, it is possible to print with excellent image quality.

  Further, in this printer apparatus 1, for example, even when the circuit board 42 is continuously exposed to the ink 2, it is possible to suppress the deposition of hydrophobic colloid on the heating resistor 43 and the elution of silicon or the like from the circuit board 42. Therefore, the ink discharge head 24 and the like are not damaged or become unusable in a short time due to the dissolution of the circuit board 42 or the clogging of the nozzle 43a, and the life of the apparatus can be extended.

  The head cartridge 3 can be attached to and detached from the printer main body 4 and the printer apparatus 1 can be attached to and detached from the ink cartridge 11 as an example. 3 can also be applied to a printer device in which 3 is integrated.

  The above is an example in which the present invention is applied to a printer device, but the present invention is not limited to the above example, and an apparatus including a portion through which a liquid flows through a flow path in which a silicon-containing material is exposed, The present invention can be widely applied to other liquid ejecting apparatuses that eject liquid. For example, a facsimile, a copying machine, a discharge device for a DNA chip in liquid (Japanese Patent Laid-Open No. 2002-253200), a liquid discharge device that discharges a liquid containing conductive particles for forming a wiring pattern of a printer wiring board, and the like It is also applicable to.

  In the above description, the ink discharge head 24 that heats and discharges the ink 2 by one heating resistor 46 has been described as an example. However, the present invention is not limited to such a structure, and includes a plurality of pressure generating elements. The present invention can also be applied to a liquid ejection apparatus including ejection means that can control the ejection direction by supplying different energy to each pressure generating element or energy at different timings.

  In the above description, the electrothermal conversion method in which the ink 2 is heated from one nozzle 43a while being heated by one heating resistor 46 is adopted. However, the present invention is not limited to this method. An electromechanical conversion method in which ink is electromechanically ejected from a nozzle by a mechanical conversion element or the like (JP 55-65559 A, JP 62-160243 A, JP 2-270561 A). It may be.

  In the above, the line type printer apparatus 1 has been described as an example. However, the present invention is not limited to this. For example, a serial type liquid in which the ink head moves in a direction substantially orthogonal to the running direction of the recording paper P is described. The present invention can also be applied to a discharge device.

  Hereinafter, samples in which ink is actually prepared as a recording liquid to which the present invention is applied will be described.

<Sample 1>
In sample 1, yellow ink was prepared. When preparing a yellow ink, C.I. I. 3 parts by weight of direct yellow 132, 76.7 parts by weight of water as a solvent, 10 parts by weight of 2-pyrrolidone as another solvent, 10 parts by weight of glycerin, and acetylene glycol manufactured by Air Products as a surfactant (product) Name: Surfinol 465) 0.3 parts by weight and a suitable amount of triethanolamine as a pH adjuster were mixed to prepare an ink precursor exhibiting pH 7.

  Then, an appropriate amount of CeO was added so that 3 ppm of cerium oxide (hereinafter referred to as CeO) was contained as a hydrophobic colloid with respect to the total amount of the ink. Thus, a yellow ink having a pH of 7 and having a zeta potential of CeO as a hydrophobic colloid of about +10 mV was prepared.

<Sample 2>
Sample 2 was the same as Sample 1, except that an appropriate amount of CeO was added to the total amount of ink to contain 15 ppm, and the amount of triethanolamine added was adjusted to show pH 8. A yellow ink having a pH of 8 and a hydrophobic colloid of CeO having a zeta potential of about −5 mV was prepared.

<Sample 3>
In sample 3, except that an appropriate amount of CeO was added to the total amount of ink so as to contain 1000 ppm, pH was 8 as in sample 2, and the zeta potential of CeO serving as a hydrophobic colloid was about −5 mV. A yellow ink was prepared.

<Sample 4>
In sample 4, cyan ink was prepared. When preparing a cyan-based ink, C.I. I. 3 parts by weight of Direct Blue 199, 76.7 parts by weight of water as a solvent, 10 parts by weight of 2-pyrrolidone as another solvent, 10 parts by weight of glycerin, and acetylene glycol manufactured by Air Products as a surfactant (product) Name: Surfinol 465) 0.3 parts by weight and a suitable amount of triethanolamine as a pH adjuster were mixed to prepare an ink precursor exhibiting pH 9.

Then, an appropriate amount of Al ₂ O ₃ was added so that 3 ppm of aluminum oxide (hereinafter referred to as Al ₂ O ₃ ) was contained as a hydrophobic colloid with respect to the total amount of ink. In this way, a cyan ink having a pH of 9 and having a zeta potential of Al ₂ O ₃ as a hydrophobic colloid of about +3 mV was prepared.

<Sample 5>
In Sample 5, except that the _Al 2 _{O 3} so as to 15ppm contained in appropriate amounts added to total amount ink, pH in the same manner as in Sample 4 represents 9, _Al 2 _{O 3} as a hydrophobic colloid A cyan ink having a zeta potential of about +3 mV was prepared.

<Sample 6>
In sample 6, barium sulfate (hereinafter referred to as BaSO ₄ ) was used as a hydrophobic colloid with respect to the total amount of ink, and an appropriate amount of this BaSO ₄ was added to contain 3 ppm, and addition of triethanolamine Except for adjusting the amount to show pH 6.5, a yellow ink showing pH 6.5 in the same manner as Sample 1 and having a zeta potential of BaSO ₄ as a hydrophobic colloid of about 0 mV was obtained. Prepared.

<Sample 7>
In the sample 7, BaSO ₄ was used as a hydrophobic colloid with respect to the total amount of the ink, and an appropriate amount of this BaSO ₄ was added so as to contain 15 ppm, and the addition amount of triethanolamine was adjusted to show pH 7. Except for the above, a cyan ink having a pH of 7 and having a zeta potential of BaSO ₄ as a hydrophobic colloid of about −10 mV was prepared in the same manner as Sample 4.

<Sample 8>
For sample 8, a yellow ink showing pH 7 was prepared in the same manner as sample 1 except that no hydrophobic colloid was contained.

<Sample 9>
For Sample 9, a yellow ink showing pH 9 was prepared in the same manner as Sample 8, except that the amount of triethanolamine added was adjusted to show pH 9.

<Sample 10>
In Sample 10, a cyan ink having a pH of 7 was prepared in the same manner as Sample 4, except that no hydrophobic colloid was contained and that the amount of triethanolamine added was adjusted to show a pH of 7.

<Sample 11>
For sample 11, a cyan ink having a pH of 9 was prepared in the same manner as sample 4 except that no hydrophobic colloid was contained.

<Sample 12>
In sample 12, silica (hereinafter referred to as SiO ₂ ) was used as a hydrophobic colloid with respect to the total amount of ink, and an appropriate amount of this SiO ₂ was added to contain 10 ppm, and the amount of triethanolamine added The yellow ink was prepared in the same manner as Sample 1 except that the pH was adjusted to show pH 7 and the zeta potential of SiO _{2 serving} as a hydrophobic colloid was adjusted to about −20 mV.

<Sample 13>
In sample 13, except that the amount of triethanolamine added was adjusted to show pH 9, it showed pH 9 in the same manner as sample 12, and the zeta potential of SiO _{2 serving} as a hydrophobic colloid was set to about −30 mV. A yellow ink was prepared.

<Sample 14>
Sample 14 had a pH of 6 in the same manner as Sample 5 except that the amount of triethanolamine added was adjusted to show pH 6, and the zeta potential of Al ₂ O _{3 serving} as a hydrophobic colloid was +40 mV. Cyan-based ink was prepared to a degree.

<Sample 15>
Sample 15 has a pH of 6.5 in the same manner as Sample 2 except that the amount of triethanolamine added is adjusted to show pH 6.5, and the zeta potential of CeO as a hydrophobic colloid is about +20 mV. A yellow ink was prepared.

  Next, the ink cartridge filled with each sample is formed on a circuit board made of a silicon wafer with a nozzle diameter of 20 μm and a heating resistor made of a Ta-based resistor film having a length and width of 20 μm and a thickness of 0.2 μm, respectively. A head cartridge having a body (heater resistance of 100 Ω) and having a plurality of head chips with 24 nozzles is mounted, and an ink jet printing apparatus capable of mounting the head cartridge is used to drive the ink ejection head to drive the head chip. Ink was ejected from the nozzles, and a continuous ejection test was conducted to evaluate the presence or absence of deposition of silicon-containing materials in the flow path or the like and the presence or absence of non-ejection nozzles after storage for 6 months.

  At this time, the surface potential of the heating resistor was measured. For this measurement, a scanning probe microscope (AutoprobeCP) manufactured by PSI was used, and KFM measurement was performed by adding the EFM / SCM option. As a result of the measurement, the surface potential of the heating resistor was -120 mV.

The circuit board in the head chip constitutes the ink flow path, and the edge side surface that is not subjected to any surface treatment is exposed to the ink in an area of 10 cm ² with respect to 1 ml of the ink. The ink ejection head was driven by applying 0.8 W of power at a pulse current of 1.5 μsec and a frequency of 10 kHz. Specifically, it was driven at a discharge interval at which ink droplets were discharged from a single nozzle about 10,000 times per second.

  Table 1 shows the results of evaluation of continuous discharge test, presence / absence of silicon-containing material, and presence / absence of non-discharge nozzle in each sample.

  In the continuous discharge test in Table 1, the ink was stored with the head cartridge at 60 ° C. for 1 week, and then the ink droplets were discharged at the discharge interval described above. The case where the ink is ejected is indicated by a circle, and the case where even one ink is not ejected in less than 500 million times is indicated by an X, and the number of times the ink is not ejected is also shown in Table 1. The presence or absence of silicon-containing substances is determined by checking whether the silicon-containing substances are deposited in the filter, ink flow path, ink liquid chamber, etc. of the connection part after the ink is stored for 6 months at 60 ° C. with the head cartridge. Whether or not kogation has occurred is visually observed. When no silicon-containing material is precipitated and no kogation has occurred, a circle indicates, and when silicon-containing material is precipitated or kogation has occurred, × This is indicated by a mark. The presence or absence of non-ejecting nozzles was as follows: After the ink was stored for 6 months at 60 ° C. with the head cartridge, ink droplets were ejected at the above-described ejection interval, and ink droplets could be ejected without any problems from all nozzles. The case is indicated by a circle, and the case where there is even one nozzle that has failed to eject ink is indicated by a cross.

  From the evaluation results shown in Table 1, Samples 1 to 7 containing a hydrophobic colloid in which the zeta potential is positively charged in the range of 3 ppm to 1000 ppm when the pH of the ink is 4 to 6 are hydrophobic. It can be seen that the continuous discharge test, the presence / absence of a silicon-containing material, and the evaluation of the presence / absence of a non-discharge nozzle are all superior to those of Samples 8 to 11 that do not contain a colloid.

  Since Sample 8 to Sample 11 do not contain hydrophobic colloids, silicon-containing materials are deposited in the ink after a long period of use or storage for a long time. Clogging may occur, resulting in non-ejection of ink or deterioration of ejection characteristics.

In contrast to these samples, in samples 1 to 7, CeO, Al ₂ O ₃ , and BaSO ₄ contained as hydrophobic colloids are positively charged when the pH of the ink is 4 to 6. From the edge of the circuit board exposed to neutral or weakly alkaline ink, elution of silicon and the like begins, and when the ink shows acidity around the circuit board, the hydrophobic colloid positively increases the zeta potential. It is charged and adhered to the edge side surface of the circuit board, and the elution of silicon and silicon compounds from the circuit board is suppressed.

  As a result, in Samples 1 to 7, even when used for a long time or stored for a long time, the silicon or silicon compound eluted does not elute from the circuit board, and the exothermic resistor is a silicon-containing material. Kogation deposited on the top can be prevented. In addition, clogging caused by precipitation of silicon or the like eluted from the circuit board as a silicon-containing material in the nozzle or the ink flow path can be prevented.

  Therefore, Sample 1 to Sample 7 can prevent ink non-ejection and deterioration of ejection characteristics.

Further, from the evaluation results shown in Table 1, Samples 1 to 7 containing CeO, Al ₂ O ₃ , and BaSO ₄ as hydrophobic colloids are compared with Samples 12 and 13 containing SiO ₂ as a hydrophobic colloid. It can be seen that the continuous discharge test, the presence / absence of a silicon-containing material, and the evaluation of the presence / absence of a non-discharge nozzle are all excellent.

Sample 12 and sample 13, as can be seen from the characteristic results shown in FIG. 4 described above, SiO ₂ is exposed from the zeta potential is not positively charged at pH4~6 ink, for example neutral or alkalescent ink Even if elution of silicon or the like starts from the edge side surface of the circuit board and the ink becomes acidic around the circuit board, SiO ₂ does not adhere to the edge side surface of the circuit board that is negatively charged. Silicon and the like continue to elute from the edge side surface of the circuit board, causing kogation on the heating resistor and clogging of the nozzles, resulting in ink non-ejection and deterioration of ejection characteristics.

On the other hand, in Sample 1 to Sample 7, as can be seen from the characteristic results shown in FIG. 4 described above, CeO, Al ₂ O ₃ and BaSO ₄ contained as a hydrophobic colloid are neutral or weakly alkaline inks, for example. When the elution of silicon or the like starts from the edge side surface of the circuit board exposed to the ink, and the ink becomes acidic around the circuit board, the zeta potential is appropriately positively charged. It adheres appropriately to the edge side surface of the circuit board to be performed, and appropriately suppresses elution of silicon, silicon compounds, etc. from the circuit board. Therefore, Sample 1 to Sample 7 can prevent ink non-ejection and deterioration of ejection characteristics.

From the above, when preparing the ink, as a hydrophobic colloid, CeO, Al ₂ O ₃ , and BaSO ₄ that have a positive zeta potential when the pH of the ink is 4 to 6 are ₃ ppm to 1000 ppm. Containing in the range suppresses elution of silicon and silicon compounds from the circuit board, so continuous discharge of 500 million times or more is possible, and it is used for a long time or stored for a long time. It can also be seen that it is very important in preparing an excellent ink in which the silicon-containing material does not cause clogging in the nozzles and the ink flow paths.

  Furthermore, from the evaluation results shown in Table 1, in Samples 1 to 7, in which the pH of the ink was adjusted and the zeta potential of the hydrophobic colloid was charged to +10 mV or less, the samples in which the zeta potential of the hydrophobic colloid was charged to +40 mV 14 and the sample 15 charged with a zeta potential of +30 mV show that the continuous discharge test is superior.

Since Sample 14 and Sample 15 contain CeO and Al ₂ O ₃ as hydrophobic colloids, as in Samples 1 to 7, elution of silicon and silicon-containing materials become kogation on the heating resistor. Can be prevented.

However, in these samples, while continuously ejecting, Al ₂ O ₃ that makes the zeta potential contained in the ink +40 mV or CeO that makes +30 mV positive, specifically, except for the periphery of the circuit board, Since the charged hydrophobic colloid adheres to the negatively charged heating resistor with a surface potential of -120 mV, kogation with the hydrophobic colloid as the main component occurs on the heating resistor when continuously ejected about 200 million times. Cause non-ejection of ink.

  On the other hand, in samples 1 to 7, the zeta potential of the hydrophobic colloid contained in the ink is charged at +10 mV or less, and the hydrophobic colloid charged to +10 mV or less other than around the circuit board is negatively charged. As a result, it is possible to prevent the occurrence of kogation mainly composed of a hydrophobic colloid on the heating resistor. Drops can be continuously discharged.

  From the above, when preparing the ink, adjusting the pH of the ink to charge the zeta potential of the hydrophobic colloid to +10 mV or less means that the hydrophobic colloid adheres to the negatively charged heating resistor and the coagulation is performed. It can be seen that it is very important in preparing an excellent ink that can suppress gating and can continuously eject 500 million times or more.

1 is a perspective view showing an ink jet printer apparatus to which the present invention is applied. It is a perspective view which shows the inkjet print head cartridge with which the inkjet printer apparatus is equipped. It is sectional drawing which shows the same inkjet print head cartridge. It is a characteristic view which shows the relationship between pH of a hydrophobic colloid, and a zeta potential. FIG. 3 is a schematic diagram illustrating a relationship between an ink cartridge and a cartridge body in the inkjet printhead cartridge. It is a top view which shows the discharge surface of the same inkjet print head cartridge. It is sectional drawing which shows typically the head chip of the same inkjet print head cartridge. FIG. 5 is a cross-sectional view illustrating a state in which the head chip discharges ink droplets and ink bubbles are formed in the ink liquid chamber. FIG. 6 is a cross-sectional view illustrating a state in which the head chip ejects ink droplets, and illustrates a state in which ink droplets are ejected from nozzles by ink bubbles. It is sectional drawing which shows typically the state in which the hydrophobic colloid adhered to the edge side surface of the circuit board in the head chip. FIG. 2 is a side view schematically showing a part of the ink jet printer apparatus. FIG. 2 is a side view schematically showing a part of the ink jet printer apparatus.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Inkjet printer apparatus, 2 ink, 3 inkjet print head cartridge, 4 printer main body, 11 ink cartridge, 21 cartridge main body, 24 ink discharge head, 24a discharge surface, 32 ink flow path, 41 head chip, 42 circuit board, 42a edge End side, 43 nozzle sheet, 43a nozzle, 44 film, 45 ink chamber, 46 heating resistor

Claims (21)

The silicon-containing material is guided to the discharge port through the liquid flow path where the silicon-containing material is exposed, and is discharged from the discharge port to the object by being pressed with the pressure generated by the pressure generating element provided corresponding to the discharge port. In the adhering recording liquid,
The dye, the solvent for dispersing or dissolving the dye, and the zeta potential is charged to +10 mV or less when the recording liquid exhibits weak alkalinity or alkalinity, and the pH of the recording liquid is in the range of 4 to 6. A recording liquid characterized by containing a hydrophobic colloid sometimes having a positive zeta potential.   The recording liquid according to claim 1, wherein the hydrophobic colloid contains one or more of aluminum oxide, cerium oxide, barium sulfate, and iron hydroxide.   2. The recording liquid according to claim 1, wherein the recording liquid contains 3 ppm or more of the hydrophobic colloid. Discharging means for discharging the liquid guided to the discharge port through the liquid flow path exposing the silicon-containing material by the pressure generated by the pressure generating element provided corresponding to the discharge port and discharging from the discharge port. In a liquid cartridge that is detachably mounted on a liquid ejection device having a liquid supply source for the ejection means,
A liquid filling part filled with the liquid;
The liquid is a dye, a solvent that disperses or dissolves the dye, and when the liquid exhibits weak alkalinity or alkalinity, the zeta potential is charged to +10 mV or less, and the pH of the liquid is in the range of 4 or more and 6 or less. A liquid cartridge comprising: a hydrophobic colloid having a positive zeta potential when the zeta potential is positively charged.   5. The liquid cartridge according to claim 4, wherein the liquid contains one or more of aluminum oxide, cerium oxide, barium sulfate, and iron hydroxide as the hydrophobic colloid.   5. The liquid cartridge according to claim 4, wherein the liquid contains 3 ppm or more of the hydrophobic colloid. In a liquid ejection cartridge that is detachably attached to a liquid ejection device that ejects liquid and adheres to an object,
A liquid filling portion filled with the liquid;
The liquid discharged from the liquid filling portion through the liquid flow path where the silicon-containing material is exposed to the discharge port is pressed by the pressure generated by the pressure generating element provided corresponding to the discharge port. Discharge means for discharging from the outlet,
The liquid is a dye, a solvent that disperses or dissolves the dye, and when the liquid exhibits weak alkalinity or alkalinity, the zeta potential is charged to +10 mV or less, and the pH of the liquid is in the range of 4 or more and 6 or less. And a hydrophobic colloid that positively charges the zeta potential when the liquid discharge cartridge is used.   8. The liquid discharge cartridge according to claim 7, wherein the liquid contains one or more of aluminum oxide, cerium oxide, barium sulfate, and iron hydroxide as the hydrophobic colloid.   8. The liquid ejection cartridge according to claim 7, wherein the liquid contains 3 ppm or more of the hydrophobic colloid.   8. The liquid ejection cartridge according to claim 7, wherein the silicon-containing material is a silicon wafer.   The liquid discharge cartridge according to claim 7, wherein the pressure generating element is negatively charged.   The liquid discharge cartridge according to claim 7, wherein a plurality of the discharge ports are provided in a substantially straight line. In a liquid ejection device that ejects liquid and adheres to an object,
Discharge discharged from the discharge port by pressing the liquid guided to the discharge port through the liquid flow path exposing the silicon-containing material with the pressure generated by the pressure generating element provided corresponding to the discharge port. Means,
A liquid cartridge filled with the liquid and serving as a supply source of the liquid to the discharge means;
The liquid is charged with a dye, a solvent for dispersing or dissolving the dye, and charged with a zeta potential of +10 mV or less when the liquid exhibits weak alkalinity or alkalinity, and the pH of the liquid is 4 or more and 6 or less. A liquid ejecting apparatus comprising a hydrophobic colloid in which the zeta potential is positively charged when set to a range.   14. The liquid ejection apparatus according to claim 13, wherein the liquid contains one or more of aluminum oxide, cerium oxide, barium sulfate, and iron hydroxide as the hydrophobic colloid.   14. The liquid ejection apparatus according to claim 13, wherein the liquid contains 3 ppm or more of the hydrophobic colloid.   The liquid ejection apparatus according to claim 13, wherein the silicon-containing material is a silicon wafer.   The liquid ejection apparatus according to claim 13, wherein the heating resistor is negatively charged.   The liquid discharge apparatus according to claim 13, wherein a plurality of the discharge ports are provided in a substantially straight line. A liquid ejection method for ejecting the liquid toward the object in order to attach the liquid to the object,
In the liquid, a dye, a solvent for dispersing or dispersing the dye, and when the liquid exhibits weak alkalinity or alkalinity, the zeta potential is charged to +10 mV or less, and the pH of the liquid is in the range of 4 or more and 6 or less. When the zeta potential is at least positively charged with a hydrophobic colloid,
The liquid is discharged from the discharge port by being guided to the discharge port through the liquid flow path where the silicon-containing material is exposed, and pressed by the pressure generated by the pressure generating element provided corresponding to the discharge port. A liquid discharge method.   20. The liquid discharging method according to claim 19, wherein the liquid contains at least one of aluminum oxide, cerium oxide, barium sulfate, and iron hydroxide as the hydrophobic colloid.   The liquid discharging method according to claim 19, wherein the liquid contains 3 ppm or more of the hydrophobic colloid.

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