Inkjet ink formulations and uses thereof

Abstract

The present disclosure relates to a water-based inkjet ink formulation, which comprises a solvent containing water, at least one colorant and at least one alkali metal organosiliconate having formula (I): #imgabs0# wherein: R is a C1-C5 alkyl group; M1, M2 and M3 are each independently selected from hydrogen or a cation of an alkali metal, wherein at least one of M1, M2 and M3 is a cation of an alkali metal. The water-based inkjet ink formulation is used in a method for preventing or minimizing print head degradation. The present disclosure also relates to a printing method using the water-based inkjet ink formulation and a printing system including the formulation.

Description

Technical Field

[0001] The present disclosure relates to inkjet ink formulations and their use in preventing or minimizing printhead degradation. Background Art

[0002] Printing systems utilize printhead plates to eject ink onto substrates. Due to continuous use, sometimes under severe operating conditions such as high frequency ink ejection, high pressure and temperature, the printhead plates may be damaged.

[0003] Sometimes, the contents of the inkjet ink, alone or in conjunction with operating conditions, may cause degradation of the printhead, for example, damaging the structure and / or chemistry of the printhead.

[0004] Additives such as silicic acid, inorganic silicates or silica gel are used in inkjet ink compositions to inhibit degradation of print head plates [1]-[5].

[0005] References

[0006] [1]US 8,419,164.

[0007] [2]US 8,662,638.

[0008] [3]US 8,425,005.

[0009] [4]US 8,657,428.

[0010] [5]US 8,430,493.

[0011] The following patent applications / publications by the applicant provide potentially relevant background material and are all incorporated herein by reference in their entirety:

[0012] [6]WO 2013 / 132439(PCT / IB2013 / 51755).

[0013] [7]WO 2015 / 036865(PCT / IB2014 / 02395).

[0014] [8]WO 2017 / 208152(PCT / IB2017 / 053177).

[0015] [9]WO 2013 / 132418(PCT / IB2013 / 051716).

[0016]

[10] WO 2019 / 012456(PCT / IB2018 / 055126).

[0017]

[11] WO 2020 / 003088(PCT / IB2019 / 055288).

[0018]

[12] WO 2013 / 132420(PCT / IB2013 / 051718).

[0019]

[13] WO 2015 / 036906(PCT / IB2014 / 064277).

[0020]

[14] WO 2020 / 136517(PCT / IB2019 / 061081).

[0021] Acknowledgment of the above references herein should not be inferred as meaning that these references have any relevance to the patentability of the presently disclosed subject matter. Summary of the invention

[0022] The inventors of the present invention have developed a water-based inkjet ink formulation comprising at least one water-soluble alkali metal organosiliconate. The inventors have unexpectedly found that the presence of the alkali metal organosiliconate compound in the water-based inkjet ink formulation of the present invention provides long-term protection for print heads used in the printing process without causing a decrease in print quality and without affecting the jetting characteristics. In addition, the inventors have found that replacing the alkali metal organosiliconate with an inorganic silicate (which is known to inhibit degradation of the printhead plate) in the ink formulation at a concentration similar to that used for the alkali metal organosiliconate is not sufficient to inhibit degradation of the printhead plate, especially when used with a white pigment such as titanium dioxide (TiO2).

[0023] The inhibition of print head plate degradation by the inkjet ink compositions of the present invention is demonstrated with both white pigments and colored pigments, thereby enabling printing with a wide variety of colors and on a variety of printing substrates such as plastics (e.g., widely used with white pigments), fibrous substrates (e.g., coated and / or uncoated), and various intermediate transfer members (the latter used with indirect printing methods, e.g., as described in detail herein below).

[0024] Thus, according to one aspect thereof, the present invention provides a water-based inkjet ink formulation comprising:

[0025] (a) a solvent containing water;

[0026] (b) at least one colorant;

[0027] (c) at least one alkali metal organosilanol salt having the formula (I)

[0028]

[0029] in:

[0030] R is a C1-C5 alkyl group;

[0031] M1, M2 and M3 are each independently selected from hydrogen or a cation of an alkali metal, wherein at least one of M1, M2 and M3 is a cation of an alkali metal; and

[0032] Optionally

[0033] (d) at least one binder (eg, an organic polymer resin).

[0034] In another aspect thereof, the present invention provides a water-based inkjet ink formulation comprising:

[0035] (a) a solvent containing water;

[0036] (b) at least one colorant; and

[0037] (c) at least one alkali metal organosilanol salt having the formula (I)

[0038]

[0039] in:

[0040] R is a C1-C5 alkyl group;

[0041] M1, M2 and M3 are each independently selected from hydrogen or a cation of an alkali metal, wherein at least one of M1, M2 and M3 is a cation of an alkali metal.

[0042] In some embodiments, for example, when the water-based inkjet ink formulation is used in an indirect printing process or system, the water-based inkjet ink formulation may further include at least one binder (eg, an organic polymer resin).

[0043] In a further aspect thereof, the present invention provides a method for preventing or minimizing degradation of a printhead (e.g., a printhead used in an inkjet printing process and forming part of a printing system), the method comprising utilizing (e.g., in a printing process) a water-based inkjet ink formulation, wherein the formulation comprises at least one alkali metal organosiliconate having formula (I)

[0044]

[0045] in:

[0046] R is a C1-C5 alkyl group;

[0047] M1, M2 and M3 are each independently selected from hydrogen or a cation of an alkali metal, wherein at least one of said M1, M2 and M3 is a cation of an alkali metal, thereby preventing or minimizing print head degradation, and wherein said water-based inkjet ink formulation further comprises a solvent comprising water, at least one colorant and optionally at least one binder (e.g., an organic polymer resin).

[0048] In yet another aspect thereof, the present invention provides a method for preventing or minimizing degradation of a print head (e.g., a print head used in an inkjet printing process and forming part of a printing system), the method comprising utilizing (e.g., in a printing process) a water-based inkjet ink formulation, wherein the formulation comprises at least one alkali metal organosiliconate having formula (I)

[0049]

[0050] in:

[0051] R is a C1-C5 alkyl group;

[0052] M1, M2 and M3 are each independently selected from hydrogen or a cation of an alkali metal, wherein at least one of said M1, M2 and M3 is a cation of an alkali metal, thereby preventing or minimizing print head degradation, and wherein said water-based inkjet ink formulation further comprises a solvent comprising water and at least one colorant.

[0053] In some embodiments, for example, when the water-based inkjet ink formulation is used in an indirect printing process or system, the water-based inkjet ink formulation utilized in the method for preventing or minimizing printhead degradation may further include at least one binder (e.g., an organic polymer resin).

[0054] In yet another aspect thereof, the present invention provides a method for preventing or minimizing degradation of a printhead (e.g., a printhead used in an inkjet printing process and forming part of a printing system), the method utilizing a water-based inkjet ink formulation comprising a solvent comprising water, at least one colorant and optionally at least one binder, the method comprising adding to the water-based inkjet ink formulation a sufficient amount of at least one alkali metal organosiliconate having formula (I)

[0055]

[0056] in:

[0057] R is a C1-C5 alkyl group;

[0058] M1, M2 and M3 are each independently selected from hydrogen or a cation of an alkali metal, wherein at least one of said M1, M2 and M3 is a cation of an alkali metal, thereby preventing or minimizing print head degradation.

[0059] In another aspect thereof, the present invention provides a method for preventing or minimizing degradation of a printhead (e.g., a printhead used in an inkjet printing process and forming part of a printing system), wherein the method comprises utilizing (e.g., during the printing process) a water-based inkjet ink formulation as disclosed herein.

[0060] In a further aspect thereof, the present invention provides a water-based inkjet ink formulation as disclosed herein for use in a method of preventing or minimizing printhead degradation.

[0061] In yet another aspect thereof, the present invention provides a water-based inkjet ink formulation as disclosed herein for preventing or minimizing printhead degradation.

[0062] However, in a further aspect thereof, the present invention provides a water-based inkjet ink formulation comprising at least one alkali metal organosiliconate of formula (I) as disclosed herein for preventing or minimizing printhead degradation.

[0063] In yet another aspect thereof, the present invention provides a water-based inkjet ink formulation comprising at least one alkali metal organosiliconate of formula (I) for use in a method for preventing or minimizing printhead degradation as disclosed herein.

[0064] In yet another aspect thereof, the present invention provides a water-based inkjet ink formulation as disclosed herein for use in a printing process (eg, as described herein).

[0065] In yet another aspect thereof, the present invention provides a water-based inkjet ink formulation as disclosed herein, which formulation forms part of a printing system (eg, as described herein).

[0066] In a further aspect thereof, the present invention provides a printing method utilizing the water-based inkjet ink formulation as disclosed herein.

[0067] In yet another aspect thereof, the present invention provides a printing system comprising the water-based inkjet ink formulation as disclosed herein.

[0068] In another aspect thereof, the present invention provides a printing system comprising an image forming station, the image forming station comprising one or more printing bars, each of the one or more printing bars being configured to hold an ink formulation and comprising one or more print heads, each of the one or more print heads being configured to eject the ink formulation onto a printing substrate to form an ink image on the substrate, wherein at least one of the one or more printing bars is configured to hold the water-based inkjet ink formulation according to the present invention.

[0069] However, in another aspect thereof, the present invention provides a printing system comprising:

[0070] an intermediate transfer member including a release layer surface;

[0071] an image forming station comprising one or more printing bars, each of the one or more printing bars being configured to hold an ink formulation and comprising one or more print heads, each of the one or more print heads being configured to eject the ink formulation onto the release layer surface to form an ink image thereon, wherein at least one of the one or more printing bars is configured to hold the water-based inkjet ink formulation according to the present invention; and

[0072] A transfer station is provided for transferring the ink image from the intermediate transfer member to a printing substrate.

[0073] However, in further aspects thereof, the present invention provides a printing system and a printing method substantially as described herein. BRIEF DESCRIPTION OF THE DRAWINGS

[0074] In order to better understand the subject matter disclosed herein and to illustrate how the same may be carried out in practice, embodiments will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which:

[0075] Figure 1 is a schematic side view of a printing system (eg, a digital printing system) according to some embodiments of the present invention.

[0076] Figure 2 Shown is a top view of a scanning electron microscope (SEM) image of a coupon simulating a nozzle plate according to some embodiments of the present invention.

[0077] Figure 3 A schematic illustration of a side view of a coupon simulating a silicon nozzle plate according to some embodiments of the present invention is shown.

[0078] FIG. 4A to FIG. 4G Shown is a top view SEM image of a coupon treated with an inkjet ink formulation containing a white dye, simulating a nozzle plate.

[0079] FIG. 5A to FIG. 5C Shown is a top view SEM image of a coupon treated with an inkjet ink formulation containing a magenta dye, simulating a nozzle plate. DETAILED DESCRIPTION

[0080] The present invention is based on the novel concept of using alkali metal organosiliconates in aqueous inkjet ink formulations to inhibit degradation of print heads forming part of a printing system.

[0081] The alkali metal organosiliconate helps to increase the life of the print head used with the ink formulation in the printing process, which may be radial or indirect.

[0082] The improvement in the life of the printhead is directly related to the ability of the inkjet ink composition of the present invention to inhibit degradation of the printhead. A non-limiting example is the ability to inhibit degradation of the repellent properties of a printhead (e.g., a siliceous printhead) whose surface is coated with a liquid repellent film comprising a fluoroalkylsilane moiety.

[0083] Without wishing to be bound by theory, the inventors of the present invention believe that the alkali metal organosiliconate may provide the ink formulation with the ability to protect the surface of the printhead from chemical damage.

[0084] Thus, in one of its aspects, the present invention provides a water-based inkjet ink formulation comprising:

[0085] (a) a solvent containing water;

[0086] (b) at least one colorant; and

[0087] (c) at least one alkali metal organosilanol salt having the formula (I)

[0088]

[0089] in:

[0090] R is a C1-C5 alkyl group;

[0091] M1, M2 and M3 are each independently selected from hydrogen or a cation of an alkali metal, wherein at least one of M1, M2 and M3 is a cation of an alkali metal.

[0092] Various embodiments will be described in detail herein in conjunction with the above aspects.It should be noted that one or more embodiments described in detail in conjunction with the water-based inkjet ink formulation of the present invention may also be applicable mutatis mutandis to other aspects of the present invention, such as methods, processes, uses and systems.

[0093] In some embodiments, the water-based inkjet ink formulations of the present invention may further include at least one binder (eg, an organic polymer resin).

[0094] In some embodiments, the inkjet ink formulation comprises:

[0095] (a) a solvent containing water;

[0096] (b) at least one colorant;

[0097] (c) at least one alkali metal organosilanol salt having the formula (I)

[0098]

[0099] in:

[0100] R is a C1-C5 alkyl group;

[0101] M1, M2 and M3 are each independently selected from hydrogen or a cation of an alkali metal, wherein at least one of M1, M2 and M3 is a cation of an alkali metal; and

[0102] Optionally

[0103] (d) at least one binder (eg, an organic polymer resin).

[0104] The inkjet ink formulation according to the present invention is configured for preventing or minimizing degradation of a printhead, for example a printhead used in an inkjet printing process and forming part of a printing system.

[0105] As disclosed herein, the present invention also provides a method of preventing or minimizing print head degradation.

[0106] The alkali metal organosiliconates of the present invention can be obtained according to procedures known in the art.

[0107] In some embodiments, the alkali metal organosiliconates of the present invention are available from Wacker Silicones, Dow Chemical, and Gelest.

[0108] As used herein, the group "C1-C5 alkyl" is an alkyl group containing 1 to 5 carbon atoms (including 1 and 5 atoms), which can be linear or branched and / or substituted at any position. In some embodiments, the number of carbon atoms in the alkyl chain can be selected from 1 to 2, 1 to 3, 1 to 4, or 1 to 5. Thus, a group designated as C1-C5 alkyl will include 1, 2, 3, 4, or 5 carbon atoms.

[0109] Examples of alkyl groups include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, and n-pentyl.

[0110] As used herein, the term "substituted" in conjunction with "C1-C5 alkyl" is a hydrocarbon group containing one or more heteroatoms, such as oxygen (e.g., OH), nitrogen (e.g., NH2), sulfur, phosphorus, halogen (e.g., F, Cl, Br or I). For example, when the alkyl group has 3 to 5 carbon atoms or 4 to 5 carbon atoms, the presence of heteroatoms can help dissolve the alkali metal organosilanol salt in the aqueous inkjet formulation.

[0111] In some embodiments according to the present invention, R is a linear or branched C1-C5 alkyl group.

[0112] In some embodiments according to the present invention, R is a substituted or unsubstituted C1-C5 alkyl group.

[0113] In some embodiments according to the present invention, R is a substituted C1-C5 alkyl.

[0114] In some embodiments according to the present invention, R is a substituted C1-C5 alkyl group, and wherein the substituent is a polar group selected to increase the solubility of the alkali metal organosilanolate in water.

[0115] In some embodiments according to the present invention, the polar substituent is a hydroxyl group.

[0116] In some embodiments according to the present invention, R is a C1-C3 alkyl group.

[0117] In some embodiments according to the present invention, R is selected from methyl, ethyl, propyl or isopropyl.

[0118] In some embodiments according to the present invention, R is methyl.

[0119] In some embodiments according to the present invention, R is ethyl.

[0120] In some embodiments according to the present invention, R is propyl.

[0121] In some embodiments according to the present invention, R is isopropyl.

[0122] As used herein, the term "alkali metal" refers to any one of the following chemical elements: lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), and francium (Fr).

[0123] In the alkali metal organosiliconates of the present invention, at least one of the O groups is negatively charged (ie, it is an anion) and is reacted with an alkali metal cation (e.g., Li + 、Na + , K + , Rb + , Cs + or Fr + ) to achieve charge balance.

[0124] In some embodiments according to the present invention, the two O groups in the alkali metal organosiliconate are negatively charged and are reacted by the alkali metal cation (e.g., Li + 、Na + , K + , Rb +, Cs + or Fr + ) to achieve charge balance, and the alkali metal cations may be the same or different.

[0125] In some embodiments according to the present invention, the three O groups in the alkali metal organosiliconate are negatively charged and are reacted by the alkali metal cation (e.g., Li + 、Na + , K + , Rb + , Cs + or Fr + ) to achieve charge balance, and the alkali metal cations may be the same or different.

[0126] In some embodiments according to the present invention, the three O groups in the alkali metal organosiliconate are negatively charged and are reacted by the alkali metal cation (e.g., Li + 、Na + , K + , Rb + , Cs + or Fr + ) to achieve charge balance, the alkali metal cations are the same alkali metal cations.

[0127] In some embodiments according to the present invention, the charge balance of one or more O groups of the alkali metal organosiliconate according to the present invention can be achieved by Li + To achieve.

[0128] In some embodiments according to the present invention, the charge balance of one or more O groups of the alkali metal organosiliconate according to the present invention can be achieved by Na + To achieve.

[0129] In some embodiments according to the present invention, the charge balance of one or more O groups of the alkali metal organosiliconate according to the present invention can be achieved by K + To achieve.

[0130] In some embodiments according to the present invention, the charge balance of one or more O groups of the alkali metal organosiliconate according to the present invention can be achieved by Rb + To achieve.

[0131] In some embodiments according to the present invention, the charge balance of one or more O groups of the alkali metal organosiliconate according to the present invention can be achieved by Cs + To achieve.

[0132] In some embodiments according to the present invention, in the alkali metal organosiliconate of the present invention, when M1, M2 and M3 are independent of each other and different from hydrogen, the bond between the oxygen atom and M1, M2 and M3 is an ionic bond.

[0133] In some embodiments according to the present invention, two of M1, M2 and M3 in the alkali metal organosiliconate are hydrogen and the third is a cation of an alkali metal.

[0134] In some embodiments according to the present invention, the cation of the alkali metal is selected from Li + 、Na + , K + , Rb + , Cs + or any combination thereof.

[0135] In some embodiments according to the present invention, the cation of the alkali metal is selected from Li + 、Na + , K + or any combination thereof.

[0136] In some embodiments according to the present invention, the alkali metal cation is Na + .

[0137] In some embodiments according to the present invention, the alkali metal cation is K + .

[0138] In some embodiments according to the present invention, the alkali metal cation is Li + .

[0139] In some embodiments according to the present invention, at least one alkali metal organosiliconate is selected from the group consisting of:

[0140]

[0141]

[0142] In some embodiments according to the present invention, R is methyl and the at least one alkali metal organosilanolate is selected from the group consisting of:

[0143]

[0144] In some embodiments according to the present invention, at least one alkali metal organosiliconate is selected from the group consisting of:

[0145]

[0146] In some embodiments according to the present invention, R is methyl and the at least one alkali metal organosilanolate is selected from the group consisting of:

[0147]

[0148] In some embodiments according to the present invention, at least one alkali metal organosiliconate is selected from the group consisting of:

[0149]

[0150] In some embodiments according to the present invention, R is methyl and the at least one alkali metal organosilanolate is selected from the group consisting of:

[0151]

[0152] In some embodiments according to the present invention, the alkali metal organosiliconate is selected from the group consisting of:

[0153]

[0154] and any combination thereof.

[0155] In some embodiments according to the present invention, R is methyl and the alkali metal organosilanolate is selected from the group consisting of:

[0156] and any combination thereof.

[0157] In some embodiments according to the present invention, the alkali metal organosiliconate is selected from the group consisting of:

[0158]

[0159] and any combination thereof.

[0160] In some embodiments according to the present invention, R is methyl and the alkali metal organosilanolate is selected from the group consisting of:

[0161] and any combination thereof.

[0162] In some embodiments according to the present invention, the alkali metal organosiliconate is selected from the group consisting of:

[0163] and combinations thereof.

[0164] In some embodiments according to the present invention, R is methyl and the alkali metal organosilanolate is selected from the group consisting of:

[0165] and combinations thereof.

[0166] In some embodiments according to the present invention, the alkali metal organosiliconate is selected from the group consisting of:

[0167] and combinations thereof.

[0168] In some embodiments according to the present invention, the alkali metal organosiliconate is selected from the group consisting of:

[0169] and combinations thereof.

[0170] In some embodiments according to the present invention, R is methyl and the alkali metal organosilanolate is selected from the group consisting of:

[0171] and combinations thereof.

[0172] In some embodiments according to the present invention, R is methyl and the alkali metal organosilanol

[0173] The salt is selected from the group consisting of:

[0174] and combinations thereof.

[0175] In some embodiments according to the present invention, at least one alkali metal organosiliconate is

[0176] In some embodiments according to the present invention, at least one alkali metal organosiliconate is

[0177] In some embodiments according to the present invention, the at least one alkali metal organosiliconate is sodium methylsiliconate, which may sometimes be referred to as methyl-silanetriosodium salt or sodium methylsilanetriolate.

[0178] In some embodiments according to the present invention, the at least one alkali metal organosiliconate is sodium methylsiliconate having CAS number 16589-43-8.

[0179] In some embodiments according to the present invention, the at least one alkali metal organosiliconate is sodium methylsiliconate having the chemical formula CH5NaO3Si.

[0180] In some embodiments according to the present invention, the at least one alkali metal organosiliconate is sodium methylsiliconate having the chemical formula CH3Na3O3Si.

[0181] In some embodiments according to the present invention, at least one alkali metal organosiliconate is

[0182] In some embodiments according to the present invention, at least one alkali metal organosiliconate is

[0183] In some embodiments according to the present invention, the at least one alkali metal organosiliconate is potassium methylsiliconate, which may sometimes be referred to as potassium methylsilanetriol or potassium methylsilanetriol.

[0184] In some embodiments according to the present invention, the at least one alkali metal organosiliconate is potassium methylsiliconate having CAS number 31795-24-1.

[0185] In some embodiments according to the present invention, the at least one alkali metal organosiliconate is potassium methylsiliconate having the chemical formula CH5KO3Si.

[0186] In some embodiments according to the present invention, the at least one alkali metal organosiliconate is potassium methylsiliconate having the chemical formula CH3K3O3Si.

[0187] In some embodiments, water-based inkjet ink formulations according to the present invention are free of one or more inorganic silicates.

[0188] In some embodiments, the water-based inkjet ink formulations according to the present invention may further include one or more inorganic silicates.

[0189] In some embodiments, the water-based inkjet ink formulations according to the present invention may further comprise one or more inorganic silicates as dispersants.

[0190] In some embodiments, the water-based inkjet ink formulation according to the present invention may also include one or more inorganic silicates that can prevent or minimize printhead degradation, for example where the ink formulation includes a colored ink. To this end, the effects of the one or more inorganic silicates and at least one alkali metal organosiliconate of the present invention may provide an additive effect. Sometimes, the effect may be synergistic.

[0191] In some embodiments, the water-based inkjet ink formulations according to the present invention are free of silica gel.

[0192] In some embodiments, the water-based inkjet ink formulations according to the present invention may further include one or more silica gels.

[0193] In some embodiments, one or more silica gels can prevent or minimize printhead degradation, for example where the ink formulation comprises a colored ink. To this end, the effects of the one or more silica gels and at least one alkali metal organosiliconate of the present invention can provide an additive effect. Sometimes, the effect can be synergistic.

[0194] As used herein in context, the term "about" refers to ± 10% of the indicated value.

[0195] In some embodiments, at least one alkali metal organosiliconate is present in a concentration of at least about 0.01 w / w%, sometimes at least about 0.05 w / w%, and even sometimes at least about 0.1 w / w% in a water-based inkjet ink formulation according to the present invention.

[0196] In some embodiments, at least one alkali metal organosiliconate is present in the water-based inkjet ink formulation according to the present invention at a concentration of at least about 0.1 w / w %.

[0197] In some embodiments, at least one alkali metal organosiliconate is present in the water-based inkjet ink formulation according to the present invention at a concentration of about 0.1 w / w %.

[0198] In some embodiments, at least one alkali metal organosiliconate is present in a water-based inkjet ink formulation according to the present invention at a concentration between about 0.01 w / w% and about 1.0 w / w%, inclusive. Any value within the above concentration range is within the scope of the present invention, for example, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.10, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19, 0.20, 0.21, 0.22, 0.23, 0.24, 0.25, 0.26, 0.27, 0.28, 0.29, 0.30, 0.31, 0.32, 0.33, 0.34, 0.35, 0.36, 0.37, 0.38, 0.39, 0.40, 0.41, 0.42, 0.43, 0.44, 0.45, 0.46, 0.47, 0.48, 0.49, 0.50, 0.51, 0.52, 0.53, 0.54, 0.55, 0.56, 0.57, 0.58, 0.59, 0.60, 0.61, 0.62, 0.63, 0.64, 0.65 2. 0.23, 0.24, 0.25, 0.26, 0.27, 0.28, 0.29, 0.30, 0.31, 0.32, 0.33, 0.34, 0.35, 0.36, 0.37, 0.38, 0.39, 0.40, 0.41, 0.42, 0.43, 0.44, 0.45, 0.46, 0.47, 0.48, 0.49, 0.50, 0.51, 0.52, 0.53, 0.54, 0.55, 0.56, 0.57, 0.58, 0.59, 0.60, 0.61, 0.62, 0.63, 0.64, 0.65, 0.66, 0.67, 0.68, 0.69, 0.70, 0.71, 0.72, 0.73, 0.74, 0. 75, 0.76, 0.77, 0.78, 0.79, 0.80, 0.81, 0.82, 0.83, 0.84, 0.85, 0.86, 0.87, 0.8 8. 0.89, 0.90, 0.91, 0.92, 0.93, 0.94, 0.95, 0.96, 0.97, 0.98, 0.99, 1.00w / w%.

[0199] In some embodiments, at least one alkali metal organosiliconate is present in the water-based inkjet ink formulation according to the present invention at a concentration between about 0.05 w / w % and about 0.5 w / w %, inclusive. Any value within the above concentration range is within the scope of the present invention, for example, 0.05, 0.06, 0.07, 0.08, 0.09, 0.10, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19, 0.20, 0.21, 0.22, 0.23, 0.24, 0.25, 0.26, 0.27, 0.28, 0.29, 0.30, 0.31, 0.32, 0.33, 0.34, 0.35, 0.36, 0.37, 0.38, 0.39, 0.40, 0.41, 0.42, 0.43, 0.44, 0.45, 0.46, 0.47, 0.48, 0.49, 0.50 w / w%.

[0200] In some embodiments, at least one alkali metal organosiliconate is present in the water-based inkjet ink formulation according to the present invention at a concentration between about 0.1 w / w % and about 0.5 w / w %, inclusive. Any value within the above concentration range is within the scope of the present invention, for example, 0.10.0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19, 0.20, 0.21, 0.22, 0.23, 0.24, 0.25, 0.26, 0.27, 0.28, 0.29, 0.30, 0.31, 0.32, 0.33, 0.34, 0.35, 0.36, 0.37, 0.38, 0.39, 0.40, 0.41, 0.42, 0.43, 0.44, 0.45, 0.46, 0.47, 0.48, 0.49, 0.50. Sometimes, at least one alkali metal organosiliconate is present in a water-based inkjet ink formulation according to the present invention at a concentration of about 0.15, 0.20, 0.25, 0.30, 0.35, 0.40 or 0.45 w / w %.

[0201] Unless otherwise stated, "concentration" refers to w / w - that is, the weight of a component of a water-based inkjet ink formulation per the total weight of the formulation.

[0202] The alkali metal organosiliconate according to the present invention may be added to or may form part of an inkjet ink formulation known in the art. Non-limiting examples of ink formulations that can be used in the present invention are the ink formulations disclosed in the applicant's patent publications WO 2013 / 132439 (PCT / IB2013 / 51755) [6], WO 2015 / 036865 (PCT / IB2014 / 02395) [7], WO 2017 / 208152 (PCT / IB2017 / 053177) [8], the contents of each of which are incorporated herein by reference.

[0203] The water-based inkjet ink formulations of the present invention are aqueous inks. In some embodiments, water comprises at least about 30 w / w %, sometimes about 50 w / w % or more of the formulation.

[0204] In some embodiments according to the present invention, water constitutes about 30 w / w% to about 65 w / w%, including 30 w / w% and 65 w / w%. Any value within the above concentration range is within the scope of the present invention, for example, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64 and 65 w / w%.

[0205] In some embodiments, the water-based inkjet ink formulations of the present invention may further include at least one co-solvent.

[0206] In some embodiments, the water-based inkjet ink formulations of the present invention may also optionally include one or more water-soluble co-solvents.

[0207] In some embodiments according to the present invention, the water-based ink formulation may further comprise at least one binder.

[0208] In some embodiments, at least one binder is dispersible or at least partially soluble in water and optionally a co-solvent.

[0209] In some embodiments, at least one binder is dispersed or at least partially dissolved in water and optionally a co-solvent.

[0210] In some embodiments, at least one binder is an organic polymer resin binder.

[0211] In some embodiments, at least one binder is an organic polymer resin binder dispersed or at least partially dissolved in water and optionally a co-solvent.

[0212] In some embodiments according to the present invention, at least one binder in the ink formulation is an anionic binder, such as an acrylic binder and / or a sulfonic acid binder. Similar anionic binders are within the scope of the present invention.

[0213] In some embodiments according to the present invention, at least one binder in the ink formulation is a negatively charged organic polymer resin.

[0214] In some embodiments according to the present invention, the average molecular weight of the negatively charged organic polymer resin is at least 8,000.

[0215] In some embodiments according to the present invention, at least one binder in the ink formulation is an acrylic polymer and / or an acrylic-styrene copolymer (eg, having an average molecular weight of about 60,000 g / mol).

[0216] In some embodiments according to the present invention, at least one binder is present in the water-based inkjet ink formulation according to the present invention at a concentration between about 5.0 w / w% and about 15.0 w / w%, inclusive. Any value within the above concentration range is within the scope of the present invention, for example, 5.0, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5, 10.0, 10.5, 11.0, 11.5, 12.0, 12.5, 13.0, 13.5, 14.0, 14.5, 15.0 w / w%.

[0217] In some embodiments according to the present invention, at least one binder is present in the water-based inkjet ink formulation according to the present invention at a concentration between about 6.0 w / w% and about 12.0 w / w%, inclusive. Any value within the above concentration range is within the scope of the present invention, for example, 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5, 10.0, 10.5, 11.0, 11.5, 12.0 w / w%.

[0218] In some embodiments according to the present invention, the water-based ink formulation may also contain at least one binder and be used in an indirect printing process. For this purpose, at least one binder is present in the water-based inkjet ink formulation according to the present invention at a concentration between about 5.0 w / w% and about 15.0 w / w% (sometimes between about 6.0 w / w% and about 12.0 w / w%) (including 5.0 w / w% and 15.0 w / w%). Any value within the above concentration range is within the scope of the present invention, for example, 5.0, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5, 10.0, 10.5, 11.0, 11.5, 12.0, 12.5, 13.0, 13.5, 14.0, 14.5, 15.0 w / w%.

[0219] Non-limiting examples of binders include polystyrene-acrylate copolymers, polyacrylate polymers, polyurethanes (eg, aliphatic polyurethanes such as anionic aliphatic polyurethanes), polyurethane-acrylate copolymers, and polyesters (eg, polyethylene terephthalate).

[0220] Exemplary styrene-acrylic acid (or polystyrene-acrylate) copolymers include 77E, 586, 90. 8085 and ECO 2177.

[0221] Exemplary polyurethanes include R-563, an anionic aliphatic polyurethane from DSM-PUD.

[0222] Exemplary acrylic or polyacrylic adhesives include 538, i.e. acrylic polymer emulsion.

[0223] Exemplary polyesters include Plascoat Z-105, Plascoat Z-730, and Plascoat Z-750 (all from GOO Chemicals).

[0224] Binders may be provided in various forms such as dispersions or emulsions, with water typically being the primary carrier liquid.

[0225] In some embodiments, the adhesive is a styrene-acrylic emulsion.

[0226] In some embodiments, ink formulations according to the present invention may further comprise at least one plasticizer.

[0227] The non-limiting examples of plasticizer families include urea derivatives and sorbitan derivatives. Such sorbitan derivatives can include derivatives such as sorbitan esters (such as SPAN 20, SPAN 40, SPAN 60 and SPAN 80) and polyethoxylated sorbitan esters (e.g., polyethoxylated sorbitan monoesters, such as TWEEN 20, TWEEN 40, TWEEN 60 and TWEEN 80).

[0228] In some embodiments according to the present invention, at least one plasticizer is present in a water-based inkjet ink formulation according to the present invention at a concentration between about 2.0 w / w% and about 6.0 w / w%, inclusive. Any value within the above concentration range is within the scope of the present invention, for example, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4.0, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, 5.0, 5.1, 5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 2.8, 5.9 and 6.0 w / w%.

[0229] In some embodiments, the plasticizer is TWEEN 20.

[0230] In some embodiments, ink formulations according to the present invention may further comprise at least one dispersant.

[0231] Non-limiting examples of suitable dispersants are polyanionic and polymeric dispersants.

[0232] In some embodiments, the dispersant is Ultra PX-4575.

[0233] In some embodiments according to the present invention, at least one dispersant is present in the water-based inkjet ink formulation according to the present invention at a concentration between about 1.0 w / w% and about 2.5 w / w%, including 1.0 w / w% and 2.5 w / w%. Any value within the above concentration range is within the scope of the present invention, for example, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4 and 2.5 w / w%.

[0234] In some embodiments, the ink formulations according to the present invention may further comprise at least one additive.

[0235] Non-limiting examples of such additives are surfactants (e.g., for reducing the surface tension of the formulation and / or improving its wetting properties), such as siloxanes and siloxane copolymers, e.g., polyether siloxane copolymers. Such surfactants are commercially available, e.g., as Wet 240, Wet 280, Twin 4100, 348, 349 and 3455 Commercially available.

[0236] Another non-limiting exemplary additive is a surface energy modifier (e.g., for reducing the surface energy of the formulation), such as a silicone-based surfactant, such as a polysiloxane-polyoxyalkylene copolymer. Such surface energy modifiers are commercially available, for example, as 307, 333 and 378 commercially available.

[0237] In some embodiments, the additive is Wet 240.

[0238] In some embodiments, the additive is 333.

[0239] In some embodiments according to the present invention, at least one additive (e.g., a surfactant) is present in a water-based inkjet ink formulation according to the present invention at a concentration between about 1.5 w / w% and about 3.0 w / w%, including 1.5 w / w% and 3.0 w / w%. Any value within the above concentration range is within the scope of the present invention, for example, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9 and 3.0 w / w%.

[0240] In some embodiments, the surfactant is a nonionic surfactant.

[0241] In some embodiments, the surfactant is an anionic surfactant.

[0242] In some embodiments, the ink formulation according to the present invention may also include at least one co-solvent. In some embodiments, the co-solvent is miscible with water. In some embodiments, the co-solvent is miscible with water at at least one specific temperature in the range of 20°C to 60°C, whereby the solvent is a single-phase solvent. In some embodiments, the co-solvent is selected to provide a single-phase solvent with a reduced vapor pressure relative to water at at least one specific temperature in the range of 20°C to 60°C. In some embodiments, the co-solvent is selected from the group consisting of ethylene glycol, diethylene glycol, propylene glycol, glycerol, PEG400, N-methylpyrrolidone and mixtures thereof. In some embodiments, the co-solvent is selected from the group consisting of dipropylene glycol, tripropylene glycol methyl ether, DMSO and mixtures thereof. In some embodiments, the co-solvent constitutes at least 5%, at least 10%, at least 15%, at least 20%, at least 25%, at least 30%, at least 35%, or at least 40% w / w of the formulation. In some embodiments, the cosolvent constitutes up to 40%, up to 35%, up to 30%, up to 25%, up to 20%, up to 15%, up to 10%, or up to 5% w / w of the formulation. In some embodiments, the ratio of cosolvent to water is in the range of 0.1:1 to 1:1 on a weight-to-weight basis.

[0243] In some embodiments according to the present invention, the co-solvent is present in the water-based inkjet ink formulation according to the present invention at a concentration between about 12.0 w / w% and about 25.0 w / w%, inclusive. Any value within the above concentration range is within the scope of the present invention, for example, 12.0, 12.5, 13.0, 13.5, 14.0, 14.5, 15.0, 15.5, 16.0, 16.5, 17.0, 17.5, 18.0, 18.5, 19.0, 19.5, 20.0, 20.5, 21.0, 21.5, 22.0, 22.5, 23.0, 23.5, 24.0, 24.5 and 25.0 w / w%.

[0244] In some embodiments, the co-solvent is propylene glycol.

[0245] As used herein, the terms "dying agent" and "coloring agent" or any linguistic variations thereof are interchangeable.

[0246] In some embodiments, the colorant includes a pigment or a mixture of pigments.

[0247] In some embodiments according to the present invention, the pigment is present in the water-based inkjet ink formulation according to the present invention at a concentration between about 8.0 w / w% and about 18.0 w / w%, inclusive. Any value within the above concentration range is within the scope of the present invention, for example, 8.0, 8.5, 9.0, 9.5, 10.0, 10.5, 11.0, 11.5, 12.0, 12.5, 13.0, 13.5, 14.0, 14.5, 15.0, 15.5, 16.0, 16.5, 17.0, 17.5 and 18.0 w / w%.

[0248] In some embodiments, the coloring agent comprises at least about 1.0% w / w of the formulation.

[0249] In some embodiments according to the present invention, at least one dye is present in a water-based inkjet ink formulation according to the present invention at a concentration between about 1.0 w / w% and about 5.0 w / w%, including 1.0 w / w% and 5.0 w / w%. Any value within the above concentration range is within the scope of the present invention, for example, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4.0, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, 5.0 w / w%.

[0250] In some embodiments, the colorant contains less than 5% pigment.

[0251] In some embodiments according to the present invention, the coloring agent includes at least one white pigment.

[0252] In some embodiments, the white pigment is TiO2.

[0253] In some embodiments, at least one coloring agent is dispersed or at least partially dissolved in water and optionally at least one co-solvent.

[0254] In some embodiments, the various components of the ink formulations according to the present invention are as disclosed and exemplified herein.

[0255] As noted above, the inventors of the present invention have discovered that the presence of the alkali metal organosiliconate of the present invention in the disclosed ink formulations provides the beneficial effect of inhibiting one or more degradation effects of printheads used in ink jetting systems.

[0256] Thus, in another aspect thereof, the present invention provides a water-based inkjet ink formulation of the present invention for preventing or minimizing printhead degradation.

[0257] In a further aspect thereof, the present invention provides a method for preventing or minimizing degradation of a print head, the print head being used in an inkjet printing process (and forming part of a printing system), the method comprising utilizing the water-based inkjet ink formulation of the present invention in the printing process, thereby preventing or minimizing degradation of the print head.

[0258] In yet another aspect thereof, the present invention provides a method for preventing or minimizing degradation of a printhead used in an inkjet printing process and forming part of a printing system utilizing a water-based inkjet ink formulation comprising a solvent comprising water, at least one colorant and optionally at least one binder, the method comprising adding to the water-based inkjet ink formulation a sufficient amount of at least one alkali metal organosiliconate having formula (I)

[0259]

[0260] in:

[0261] R is a C1-C5 alkyl group;

[0262] M1, M2 and M3 are each independently selected from hydrogen or a cation of an alkali metal, wherein at least one of said M1, M2 and M3 is a cation of an alkali metal, thereby preventing or minimizing print head degradation.

[0263] In some embodiments of the methods of the present invention, at least one alkali metal organosiliconate is added to the ink formulation to provide a concentration of at least about 0.01 w / w % in the formulation.

[0264] In some embodiments of the methods of the present invention, at least one alkali metal organosilanol salt is added to the ink formulation to provide a concentration of at least about 0.05 w / w % in the formulation.

[0265] In some embodiments of the methods of the present invention, at least one alkali metal organosiliconate is added to the ink formulation to provide a concentration in the formulation of between about 0.01 w / w % to about 1.0 w / w %, sometimes between about 0.1 w / w % to about 0.5 w / w %.

[0266] In its further aspect, the present invention provides a method for preventing or minimizing printhead degradation, the method comprising utilizing a water-based inkjet ink formulation, wherein the formulation comprises at least one alkali metal organosiliconate having formula (I)

[0267]

[0268] in:

[0269] R is a C1-C5 alkyl group;

[0270] M1, M2 and M3 are each independently selected from hydrogen or a cation of an alkali metal, wherein at least one of said M1, M2 and M3 is a cation of an alkali metal, thereby preventing or minimizing print head degradation, and wherein the water-based inkjet ink formulation further comprises a solvent comprising water, at least one colorant and optionally at least one binder.

[0271] In some embodiments, the print head is used in an inkjet printing process.

[0272] In some embodiments, the print head forms part of a printing system.

[0273] The various embodiments described herein in detail in connection with the inkjet ink formulations of the present invention are also applicable mutatis mutandis to the methods of the present invention.

[0274] In some embodiments of the present invention, for example, in the methods disclosed herein, at least one alkali metal organosiliconate is present in the water-based inkjet ink formulation of the present invention in an amount sufficient to prevent or minimize print head degradation. In some embodiments, the sufficient amount is at least about 0.01 w / w%, and sometimes at least about 0.05 w / w%. In some embodiments, the sufficient amount is between about 0.01 w / w% and about 1.0 w / w%. Any value within the above concentration range is within the scope of the present invention, for example, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.10, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19, 0.20, 0.21, 0.2 2. 0.23, 0.24, 0.25, 0.26, 0.27, 0.28, 0.29, 0.30, 0.31, 0.32, 0.33, 0.34, 0.35, 0.36, 0.37, 0.38, 0.39, 0.40, 0.41, 0.42, 0.43, 0.44, 0.45, 0.46, 0.47, 0.48, 0.49, 0.50, 0.51, 0.52, 0.53, 0.54, 0.55, 0.56, 0.57, 0.58, 0.59, 0.60, 0.61, 0.62, 0.63, 0.64, 0.65, 0.66, 0.67, 0.68, 0.69, 0.70, 0.71, 0.72, 0.73, 0.74, 0. %. In some embodiments, a sufficient amount is between about 0.05 w / w% and about 1.0 w / w%, and sometimes even between about 0.1 w / w% and about 0.5 w / w%.

[0275] In some embodiments, preventing or minimizing printhead degradation is contemplated as preventing or minimizing degradation of at least a portion of the printhead (eg, the nozzle plate).

[0276] In some embodiments, preventing or minimizing printhead degradation is contemplated as preventing or minimizing degradation of at least a portion of a printhead nozzle plate.

[0277] In some embodiments according to the invention, preventing or minimizing printhead degradation is contemplated as inhibiting degradation of the printhead (or at least a portion of the printhead), sometimes inhibiting degradation of the liquid repellent properties of the printhead.

[0278] In some embodiments according to the present invention, preventing or minimizing printhead degradation is contemplated to provide improved compatibility of inkjet ink formulations with printheads used in inkjet printing processes.

[0279] In some embodiments according to the present invention, preventing or minimizing printhead degradation is envisioned as inhibiting degradation of the printhead (or at least a portion of the printhead), sometimes inhibiting degradation of the printhead liquid repellency properties (or at least a portion of the printhead liquid repellency properties) and providing improved compatibility of the inkjet ink formulation with the printhead used in the inkjet printing process.

[0280] In some embodiments of the present invention, print head degradation may be, for example, erosion caused by inkjet inks.

[0281] In some embodiments of the present invention, printhead degradation may be due to the alkaline nature of the inkjet ink. Without wishing to be bound by theory, sometimes, for example, when the printhead is a silicon-based printhead with a surface coated with a liquid-repellent membrane comprising a fluoroalkylsilane moiety, the alkaline inkjet ink may hydrolyze the Si-O-Si bond between the fluoroalkylsilane moiety of the liquid-repellent membrane and the printhead nozzle plate, resulting in (ink) wetting of the nozzle plate and thus degrading the jetting performance of the printhead. Prolonged contact between the ink and the nozzle plate (which is no longer protected due to hydrolysis) may even cause corrosion of the nozzle plate silicon oxide.

[0282] In some embodiments of the present invention, print head degradation may be chemical damage, for example due to inkjet inks and / or due to printing conditions such as pressure and / or temperature. In some embodiments, chemical damage may be due to a side reaction, for example, the side reaction forms at least one chemical substance that may damage the print head.

[0283] The prevention or minimization of printhead degradation effects is achieved due to the presence of an alkali metal organosiliconate in the ink formulation. In some embodiments, the effect may be attributed to the alkali metal organosiliconate alone, or sometimes may be the result of a combination of an alkali metal organosiliconate with one or more other ingredients of the ink formulation. The combined effect may provide an additive or synergistic effect.

[0284] Preventing or minimizing printhead degradation according to the present invention can provide extended life for printheads (e.g., printhead nozzle plates) used in a printing process. To this end, preventing or minimizing printhead degradation is contemplated to increase the life of printheads used in a printing process.

[0285] In some embodiments according to the present invention, the improvement in the life of the print head (e.g., print head nozzle plate) used in the printing process can be reflected by extending the life of the print head by at least 10 times, and sometimes by 100 times. For example, the life of the print head can be extended from 1 month to 2 months or from 1 month to 5 months.

[0286] Sometimes, ink formulations that do not contain the alkali metal organosiliconate of the present invention may damage the printhead within a few days, in contrast to the inks of the present invention that contain the alkali metal organosiliconate, which sometimes provide protection to the printhead for a longer period of time, such as a period of at least one month, at least two months, at least three months, at least four months, at least five months, at least six months, at least seven months, at least eight months, or at least nine months, without showing any degradation of the printhead (e.g., printhead nozzle). The protection effect can extend to a period of one year, sometimes several years. The time period detailed herein is considered to be the time period during which the printhead (e.g., printhead nozzle) is in close contact with the ink formulation.

[0287] In some embodiments, protection may extend over a period of 6 months.

[0288] Effects associated with preventing or minimizing print head degradation may be reflected in maintaining print quality over a long period of time, eg, print quality may not be impaired.

[0289] It should be noted that the term "preventing or minimizing print head degradation" or any linguistic variation thereof may be contemplated as, but not limited to, one or more of the preventing or minimizing print head degradation detailed herein above and below.

[0290] It should be noted that the term "print head degradation" or any linguistic variant thereof may be contemplated as, but not limited to, one or more of the print head degradations detailed herein above and below.

[0291] As mentioned above, the inkjet ink formulations of the present invention may be used in direct or indirect printing processes utilizing direct and indirect printing systems, respectively.

[0292] In some embodiments, the printing process is a direct printing process, ie, the ink formulation is jetted directly onto the final printed substrate.

[0293] In some embodiments, the printing process is an indirect printing process, wherein the release surface of an intermediate transfer member (ITM) is pre-treated (e.g., coated) with a treatment formulation (e.g., an aqueous treatment formulation) before an ink image is deposited onto the release surface. The treatment formulation is applied to the surface of the ITM to form a thin wet treatment layer thereon, which is subjected to a drying process on the ITM release surface, thereby leaving a thin, substantially dry treatment film on the ITM release surface. Then, droplets of an aqueous ink formulation are deposited onto the thin, substantially dry treatment film by ink jetting to form an ink image thereon. The formed ink image is then subjected to a drying process to leave an ink residue on the substantially dry treatment film. The substantially dry ink image is then transferred from the ITM surface together with the thin, substantially dry treatment film to a final printing substrate (e.g., a foil-based, paper-based, or plastic-based substrate).

[0294] Examples of such printing processes and systems are disclosed in the applicant's patent publications WO 2017 / 208152 (PCT / IB2017 / 053177) [8] and WO 2013 / 132418 (PCT / IB2013 / 051716) [9], the contents of which are incorporated herein by reference.

[0295] Simply put, Figure 1 An illustration of an exemplary indirect printing system is provided. Specifically, Figure 1 is a schematic side view of a digital printing system 10 according to some embodiments of the present invention. In some embodiments, system 10 includes a roll of flexible blanket 12 that can be cycled through an image forming station 14, a drying station 16, an imprinting station 18, and a blanket handling station 20.

[0296] As used herein, the term "blanket" refers to a flexible transfer member that can be mounted within a printing apparatus to form a belt-like structure on two or more rollers, wherein at least one roller is capable of rotating and moving the blanket (e.g., by moving its belt) so that the blanket travels around the rollers.

[0297] As used herein, the terms "blanket" and "intermediate transfer member" (ITM) are used interchangeably and refer to a flexible member including at least a release layer serving as an intermediate member, the flexible member being configured to receive an ink image and transfer the ink image to a target substrate.

[0298] In an operating mode, the image forming station 14 is configured to form a mirror image of the digital image, also referred to herein as an "ink image" (not shown), on an upper run of the surface of the blanket 12. The ink image is subsequently transferred to a target substrate (e.g., paper, folding carton, or any suitable flexible packaging in sheet or continuous web form) located below a lower run of the blanket 12.

[0299] As used herein, the terms "ink image" and "image" are interchangeable. Sometimes, the terms refer to the image formed on the blanket 12 and transferred to the target substrate. Sometimes, they refer to the printed image on the substrate itself (e.g., paper, folding carton, or any suitable flexible packaging in the form of a sheet or continuous web). Therefore, these terms should be interpreted in the context of the text in which they are used.

[0300] As used herein, the term "run" refers to the length or section of blanket 12 between any two given rollers over which blanket 12 is guided.

[0301] In some embodiments, during installation, the blanket 12 may be adhered edge to edge (e.g., seamed) to form a continuous blanket loop (not shown). Examples of methods and systems for seam installation are described in detail in the applicant's patent publication WO 2019 / 012456 (PCT / IB2018 / 055126)

[10] , the disclosure of which is incorporated herein by reference.

[0302] In some embodiments, image forming station 14 generally includes a plurality of print bars 22, each of which is mounted (e.g., using slides) on a frame (not shown) located at a fixed height above the surface of the upper run of blanket 12. In some embodiments, each print bar 22 includes a print head strip as wide as the print area on blanket 12 and includes individually controllable print nozzles.

[0303] In some embodiments, image forming station 14 may include any suitable number of bars 22, each of which may contain a printing fluid, such as a different colored aqueous ink formulation. Inks typically have visible colors such as, but not limited to, cyan, magenta, red, green, blue, yellow, black, and white. Figure 1 In the example of FIG. 1 , the image forming station 14 includes seven print bars 22 , but may include, for example, four print bars 22 of any selected colors, such as cyan, magenta, yellow, and black.

[0304] In some embodiments, one or more of the printed strips may include the water-based inkjet ink formulation of the present invention, i.e., the water-based inkjet ink formulation comprises the alkali metal organosiliconate of the present invention. Sometimes, all printed strips utilized in the printing method / system may include the water-based inkjet ink formulation of the present invention, i.e., the water-based inkjet ink formulation comprises the alkali metal organosiliconate of the present invention. Sometimes, only the printed strips including the white color may include the water-based inkjet ink formulation of the present invention, i.e., the water-based inkjet ink formulation comprises the alkali metal organosiliconate of the present invention.

[0305] In some embodiments, the printheads are configured to eject ink droplets of different colors onto the surface of the blanket 12 to form an ink image (not shown) on the surface of the blanket 12 .

[0306] In some embodiments, the various print strips 22 are spaced apart from one another along the axis of motion of the blanket 12, represented by arrow 24. In this configuration, precise spacing between the strips 22 and synchronization between the ink droplets directing each strip 22 and the moving blanket 12 are critical to achieving proper placement of the image pattern.

[0307] In some embodiments, the system 10 includes a heater, such as a hot air or air blower 26 , located between the print bars 22 and configured to partially dry ink droplets deposited on the surface of the blanket 12 .

[0308] This flow of hot air between the print swathes may help, for example, to reduce condensation at the surface of the print head and / or to handle satellites (e.g., residues or small droplets distributed around the main ink droplets), and / or to prevent clogging of the inkjet nozzles of the print head, and / or to prevent undesirable fusion of ink droplets of different colors on the blanket 12. In some embodiments, the system 10 includes a drying station 16 configured to blow hot air (or another gas) onto the surface of the blanket 12. In some embodiments, the drying station includes a blower or any other suitable drying device.

[0309] In the drying station 16, the ink image formed on the blanket 12 is exposed to radiation and / or hot air to more thoroughly dry the ink, thereby evaporating most or all of the liquid vehicle and leaving only a layer of resin and colorant that is heated to the point of presenting a tacky ink film.

[0310] In some embodiments, the system 10 includes a blanket transport / guide assembly 26' configured to move a rolling ITM, such as a blanket 12. In some embodiments, the blanket transport / guide assembly 26' includes one or more rollers 28, wherein at least one of the rollers 28 includes an encoder (not shown) configured to record the position of the blanket 12 in order to control the position of the segments of the blanket 12 relative to the corresponding print strip 22. In some embodiments, the encoders of the rollers 28 typically include rotary encoders configured to generate rotation-based position signals indicative of the angular displacement of the corresponding rollers.

[0311] Additionally or alternatively, the blanket 12 may include an integrated encoder (not shown) for controlling the operation of the various modules of the system 10. Integrated encoders are described in detail, for example, in the applicant's patent publication WO 2020 / 003088 (PCT / IB2019 / 055288)

[11] , the disclosure of which is incorporated herein by reference.

[0312] In some embodiments, the system 10 includes an impression station 18 in which the blanket 12 passes between an impression cylinder 30 and a pressure cylinder 32 configured to carry a compressible blanket.

[0313] In some embodiments, the system 10 includes a console (not shown) configured to control the various modules and components of the system 10 .

[0314] In some embodiments, the blanket treatment station 20 (which may also function as a cooling and / or cleaning station) is configured to treat the blanket, for example by cooling the blanket and / or applying a treatment fluid to the outer surface of the blanket 12, and / or cleaning the outer surface of the blanket 12. The treatment may be performed by passing the blanket 12 over one or more rollers or blades configured to apply cooling and / or cleaning and / or treatment fluid to the outer surface of the blanket.

[0315] exist Figure 1 In the example of FIG. 2 , the station 20 is mounted between two specific rollers 28 , however the station 20 may be mounted proximate to the blanket 12 at any other suitable location between the embossing station 18 and the image forming station 14 .

[0316] In some embodiments, the impression cylinder 30 of the impression station 18 is configured to impress an ink image onto a target substrate, such as a single sheet 34, which is conveyed by a substrate transport module 36 (shown schematically) from an input stack 38 to an output stack 40 via the impression cylinder 30. In some embodiments, the target substrate may include any suitable substrate, such as, but not limited to, a flexible substrate, a partially flexible substrate (e.g., having a flexible section and a rigid section), or a rigid substrate.

[0317] In some embodiments, system 10 includes an additional stamping station (not shown) to permit double-sided printing (ie, printing on both sides of sheet 34).

[0318] In alternative embodiments, different configurations of the substrate conveyor belt 36 may be used to print on a continuous web substrate, as disclosed, for example, in PCT International Publication No. WO 2020 / 136517 (PCT / IB2019 / 061081)

[14] . Detailed descriptions and various configurations of sheet-fed simplex and duplex printing systems and systems for printing on continuous web substrates are provided, for example, in PCT International Publication No. WO 2013 / 132420 (PCT / IB2013 / 051718)

[12] and PCT International Publication No. WO 2015 / 036906 (PCT / IB2014 / 064277)

[13] , the disclosures of each of which are incorporated herein by reference.

[0319] A particular configuration of system 10 is shown by way of example. However, embodiments of the present invention are in no way limited to this particular type of example system, and the principles described herein are equally applicable to any other type of printing system.

[0320] Thus, in another aspect thereof, the present invention provides an indirect printing system and an indirect printing method, for example as described in [8] and / or [9], which utilize the inkjet ink formulation of the present invention.

[0321] In another aspect thereof, the present invention provides a printing system comprising an image forming station, the image forming station comprising one or more printing bars, each of the one or more printing bars being configured to hold an ink formulation and comprising one or more print heads, each of the one or more print heads being configured to eject the ink formulation onto a printing substrate to form an ink image on the substrate, wherein at least one of the one or more printing bars is configured to hold the water-based inkjet ink formulation according to the present invention.

[0322] In some embodiments, the printing substrate is substantially as disclosed herein.

[0323] In some embodiments, one or more print heads are substantially as disclosed herein.

[0324] However, in another aspect thereof, the present invention provides a printing system comprising:

[0325] an intermediate transfer member including a release layer surface;

[0326] an image forming station comprising one or more printing bars, each of the one or more printing bars being configured to hold an ink formulation and comprising one or more print heads, each of the one or more print heads being configured to eject the ink formulation onto the release layer surface to form an ink image thereon, wherein at least one of the one or more printing bars is configured to hold the water-based inkjet ink formulation according to the present invention; and

[0327] A transfer station is used to transfer the ink image from the intermediate transfer member to the printing substrate.

[0328] In some embodiments, the system of the present invention may further include a drying station configured to substantially dry (sometimes partially dry) the ink image formed on the intermediate transfer member, and wherein the transfer station is configured to transfer the substantially dry (sometimes partially dry) ink image from the intermediate transfer member to the printing substrate.

[0329] As used herein in the context, the term "substantially dry" or any linguistic variants thereof may be contemplated as partially dry, sometimes dry to the extent that solvents and / or co-solvents and / or water and / or any volatile components are present in trace amounts (e.g., amounts that do not interfere with the performance of one or more of the system, printing process, and do not interfere with print quality), or even sometimes completely dry.

[0330] In some embodiments, the intermediate transfer member is substantially as disclosed herein.

[0331] In some embodiments, one or more print heads are substantially as disclosed herein.

[0332] In some embodiments, the transfer station is substantially as disclosed herein.

[0333] In some embodiments, the drying station is substantially as disclosed herein.

[0334] In some embodiments, the printing substrate is substantially as disclosed herein. In another aspect thereof, the present invention provides a water-based inkjet ink formulation as disclosed herein for preventing or minimizing degradation of a printhead, the printhead being used in a printing process, which may be direct or indirect. The printing system utilized may be a direct or indirect system.

[0335] In some embodiments, the printhead of the present invention forms part of a direct printing system.

[0336] In some embodiments, the printhead of the present invention is an inkjet printhead.

[0337] In some embodiments, the printheads of the present invention form part of an indirect or direct printing system.

[0338] In some embodiments, a printhead of the present invention includes a printhead nozzle plate.

[0339] In some embodiments, at least a portion of a printhead of the present invention is formed from a metal oxide (eg, silicon oxide).

[0340] In some embodiments, the metal oxide is at least one selected from silicon oxide, titanium oxide, and chromium oxide.

[0341] In some embodiments, the metal nitride is at least one selected from the group consisting of titanium nitride and silicon nitride.

[0342] In some embodiments, at least a portion of the nozzle plate is coated with a film comprising SiO2 or tantalum oxide.

[0343] In some embodiments, at least a portion of a printhead of the present invention is formed from silicon (eg, silicon oxide).

[0344] In some embodiments, the entire print head nozzle is formed from silicon (eg, silicon oxide).

[0345] In some embodiments, the silicon is single crystal silicon.

[0346] In some embodiments, the silicon is polycrystalline silicon.

[0347] In some embodiments, the printheads of the present invention are formed (at least in part or in whole) from silicon coated with a liquid repellent membrane comprising fluoroalkylsilane moieties.

[0348] In some embodiments of the present invention, the liquid repellent membrane is a monolayer membrane.

[0349] In some embodiments, the print head of the present invention is coated with thermally grown silicon oxide SiO x (e.g., SiO2) is formed.

[0350] In some embodiments, the print heads of the present invention are formed (at least in part or in whole) from silicon coated with thermally grown silicon oxide SiO x (eg, SiO2) (which may be in the form of a film) that is additionally coated with a liquid repellent film comprising fluoroalkylsilane moieties.

[0351] In some embodiments, the print head of the present invention includes a nozzle plate selected from the group consisting of: (i) a silicon plate having a thermally oxidized SiO2 layer, and (ii) a self-assembled monolayer membrane plate, wherein a fluorinated alkylsilane compound is formed on an oxidized SiO2 layer provided on the silicon plate.

[0352] In some embodiments, the liquid repellent membrane containing the fluoroalkylsilane moiety is prepared by using a silane having the formula C n F 2n+1 -C m H 2m -Si-X3, wherein n represents an integer of 1 or more; m represents an integer of 0 or more; X represents an alkoxy group, an amino group or a halogen atom; and a part of X may be substituted with an alkyl group.

[0353] In some embodiments of the present invention, a compound having the formula C n F 2n+1 -C m H 2m -Si-X3 compound is C8F 17 C2H4SiCl3.

[0354] In some embodiments of the present invention, the liquid repellent film containing fluoroalkylsilane moieties is provided in the form of a monolayer protecting the Si and SiOx layers.

[0355] In some embodiments of the present invention, the liquid-repellent film is provided on the surface of the nozzle of the inkjet print head, particularly, on the surface thereof on the side facing the ink ejection direction of the nozzle.

[0356] In some embodiments of the present invention, an inkjet ink formulation is ejected from a recording head having a coating layer containing a fluorine-based polymer onto a surface of a nozzle plate.

[0357] The printhead (eg, printhead plate) of the present invention is available, for example, from Dimatix, FUJIFILM Corporation, Tokyo, Japan. Such printheads are disclosed in [1]-[5], the contents of which are incorporated herein by reference.

[0358] It should be noted that the term "print head" may be contemplated as, but is not limited to, one or more of the print heads detailed herein above and below.

[0359] Detailed description of embodiments

[0360] The following examples are not intended in any way to limit the scope of the invention as claimed.

[0361] Example 1: Testing the compatibility of ink formulations with printheads (nozzle plates)

[0362] The effect of a damaged nozzle plate on jetting stability and print quality was tested.

[0363] To predict nozzle plate durability, an immersion test was applied.

[0364] Silicon coupons simulating nozzle plates purchased from Dimatix were immersed in the test ink formulations in a manner where half of the coupon was in the test liquid and the other half was uncovered and stored for a period of up to 9 months at 50° C. According to the manufacturer, the tests were conducted at 50° C. to enhance the process and stimulate the life of the printhead.

[0365] Contact angles (CA) were measured regularly and scanning electron microscopy (SEM) was used to study the effect of ink formulation on the coupons.

[0366] Table 1 details the contents of the test ink formulations containing the white pigment titanium dioxide TiO2 (rutile).

[0367] The ink formulation is prepared by mixing the various ingredients in the specified amounts.

[0368] Table 1: White ink - general formulation

[0369]

[0370] The following alkali metal organosiliconate materials were used:

[0371] ·SILRES BS16–Wacker Silicones

[0372] XIAMETER OFS-0777 Siliconate – Dow Chemical

[0373] Potassium methylsiliconate, 40% aqueous solution – Gelest

[0374] Sodium methylsiliconate, 30% aqueous solution – Gelest

[0375] The following sodium silicate materials were used:

[0376] Sodium silicate solution - Sigma Aldrich.

[0377] Sodium metasilicate pentahydrate-Sigma Aldrich.

[0378] Two types of TiO2 pigments were used. All TiO2 grades were rutile grades.

[0379] Table 2 details the TiO2 pigments in the chloride process.

[0380] Table 3 details TiO2 pigments from the sulfuric acid process.

[0381] Table 2: TiO2 in the chloride process

[0382] name Surface treatment Kronos 2160 Al,Si Kronos 2300 Al Kronos 2310 Al,Si,Zr Tioxide R-XL Al,Si

[0383] Table 3: TiO2 in sulfuric acid process

[0384] name Surface treatment RDI-S Al, organic RDDI Al, Si, organic

[0385] In the absence of organosilicate, all tested ink formulations with TiO2 white pigment damaged the nozzle plate. In the case where alkali metal organosiliconate was present in the ink formulation at a concentration of 0.1%, no damage to the nozzle plate was observed.

[0386] Figure 2 A top view of an SEM image of a specimen (100) with a contact angle of 110°-117° is shown.

[0387] Figure 3 is a schematic illustration of a side view of a coupon (200) having a Si layer (202) on top of which there is thermally grown silicon oxide SiO x Layer (204) and a liquid repellent membrane (206) comprising fluoroalkylsilane moieties. The liquid repellent membrane is a monolayer chemically bonded to the SiO2 surface. Figure 3 The contact angle of a 0.5 μl drop of DIW (deionized water) is also shown (208, contact angle = 110° - 117°).

[0388] FIG. 4A to FIG. 4G Shown is a top view SEM image of a coupon treated with an inkjet ink formulation containing a white dye, simulating a nozzle plate.

[0389] Figure 4A and Figure 4B Coupons treated with an inkjet ink formulation without alkali metal organosiliconate or sodium silicate (white reference) at 50°C for 7 days are represented. Figure 4A Supplied at x50 magnification, while Figure 4B Supplied at x 200 magnification.

[0390] Figure 4C Coupons treated with an inkjet ink formulation with 0.1% alkali metal organosiliconate added at 50°C for 2 months are represented.

[0391] Figure 4D Coupons treated with an inkjet ink formulation with 0.1% alkali metal organosiliconate added at 50°C for 9 months are represented.

[0392] Figure 4ECoupons are represented that were treated with an inkjet ink formulation to which 0.05% alkali metal organosiliconate was added for 1 month at 50°C (similar results were obtained at 0.01% alkali metal organosiliconate - data not shown).

[0393] Figure 4F and Figure 4G Coupons are represented that were treated with an inkjet ink formulation with 0.5% sodium silicate added at 50°C for 15 days (similar results were obtained with 0.1% and 0.3% sodium silicate at 50°C for 10 days with a 101° contact angle - data not shown). Figure 4F Supplied at x50 magnification, while Figure 4G Supplied at x200 magnification.

[0394] FIG. 5A to FIG. 5C Shown is a top view SEM image of a coupon treated with an inkjet ink formulation containing a magenta dye, simulating a nozzle plate.

[0395] Figure 5A Coupons treated with an inkjet ink formulation without alkali metal organosiliconate or sodium silicate (magenta reference) at 50°C for 3 days are represented.

[0396] Figure 5B Coupons treated with an inkjet ink formulation with 0.5% alkali metal organosiliconate added at 50°C for 8 months are represented.

[0397] Figure 5C Represents coupons treated with an inkjet ink formulation with 0.5% sodium silicate added at 50°C for 8 months.

[0398] Table 4 below summarizes the test results.

[0399] Table 4: Summary of results

[0400]

[0401] Illustrative Embodiments

[0402] The following embodiments are illustrative and not intended to limit the claimed subject matter.

[0403] Embodiment 1 A water-based inkjet ink formulation, the water-based inkjet ink formulation comprising:

[0404] (a) a solvent containing water;

[0405] (b) at least one colorant; and

[0406] (c) at least one alkali metal organosilanol salt having the formula (I)

[0407]

[0408] in:

[0409] R is a C1-C5 alkyl group;

[0410] M1, M2 and M3 are each independently selected from hydrogen or a cation of an alkali metal, wherein at least one of M1, M2 and M3 is a cation of an alkali metal.

[0411] Embodiment 2 The inkjet ink formulation according to embodiment 1, further comprising at least one binder.

[0412] Embodiment 3 The inkjet ink formulation of embodiment 1 or embodiment 2, wherein R is a linear or branched C1-C5 alkyl group.

[0413] Embodiment 4 The inkjet ink formulation of any one of Embodiments 1 to 3, wherein R is a substituted or unsubstituted C1-C5 alkyl group.

[0414] Embodiment 5 The inkjet ink formulation of any one of Embodiments 1 to 4, wherein R is a substituted C1-C5 alkyl.

[0415] Embodiment 6 The inkjet ink formulation of embodiment 5, wherein R is a substituted C1-C5 alkyl group and wherein the substituent is a polar group selected to increase the solubility of the alkali metal organosilanol salt in water.

[0416] Embodiment 7 The inkjet ink formulation of embodiment 6, wherein the polar substituent is a hydroxyl group.

[0417] Embodiment 8 The inkjet ink formulation of any one of Embodiments 1 to 7, wherein R is a C1-C3 alkyl group.

[0418] Embodiment 9 The inkjet ink formulation of embodiment 8, wherein R is selected from methyl, ethyl, propyl or isopropyl.

[0419] Embodiment 10: An inkjet ink formulation as described in Embodiment 9, wherein R is methyl.

[0420] Embodiment 11 The inkjet ink formulation of any one of Embodiments 1 to 10, wherein two of the M1, M2 and M3 are hydrogen and the third is a cation of an alkali metal.

[0421] Embodiment 12: An inkjet ink formulation as described in any one of Embodiments 1 to 11, wherein the cation of the alkali metal is selected from Li + 、Na + , K + , Rb + , Cs +or any combination thereof.

[0422] Embodiment 13: An inkjet ink formulation as described in any one of Embodiments 1 to 12, wherein the cation of the alkali metal is selected from Li + 、Na + , K + or any combination thereof.

[0423] Embodiment 14: An inkjet ink formulation as described in any one of Embodiments 1 to 13, wherein the cation of the alkali metal is Na + .

[0424] Embodiment 15: An inkjet ink formulation as described in any one of Embodiments 1 to 13, wherein the cation of the alkali metal is K + .

[0425] Embodiment 16 An inkjet ink formulation as described in any one of Embodiments 1 to 13, wherein the cation of the alkali metal is Li + .

[0426] Embodiment 17 An inkjet ink formulation as described in any one of Embodiments 1 to 16, wherein R is methyl and wherein the at least one alkali metal organosilanol salt is selected from the group consisting of:

[0427]

[0428] Embodiment 18 The inkjet ink formulation of embodiment 17, wherein the at least one alkali metal organosiliconate is

[0429] Embodiment 19 The inkjet ink formulation of Embodiment 17, wherein the at least one alkali metal organosiliconate is

[0430] Embodiment 20: The inkjet ink formulation of embodiment 17, wherein the at least one alkali metal organosiliconate is

[0431] Embodiment 21 The inkjet ink formulation of Embodiment 17, wherein the at least one alkali metal organosiliconate is

[0432] Embodiment 22 The inkjet ink formulation of any one of Embodiments 1 to 21, wherein the formulation is free of one or more inorganic silicates.

[0433] Embodiment 23 The inkjet ink formulation of any one of Embodiments 1 to 22, wherein the formulation is free of silica gel.

[0434] Embodiment 24 The inkjet ink formulation of any one of Embodiments 1 to 23, wherein the at least one alkali metal organosiliconate is present in the formulation at a concentration of at least about 0.01 w / w %.

[0435] Embodiment 25 The inkjet ink formulation of any one of Embodiments 1 to 24, wherein the at least one alkali metal organosiliconate is present in the formulation at a concentration of about 0.1 w / w % or at least about 0.1 w / w %.

[0436] Embodiment 26 An inkjet ink formulation as described in any one of Embodiments 1 to 24, wherein the at least one alkali metal organosiliconate is present in the formulation at a concentration between about 0.01 w / w % and about 1.0 w / w %.

[0437] Embodiment 27 An inkjet ink formulation as described in any one of Embodiments 1 to 26, wherein the at least one alkali metal organosiliconate is present in the formulation at a concentration between about 0.1 w / w % and about 0.5 w / w %.

[0438] Embodiment 28 The inkjet ink formulation of any one of Embodiments 1 to 27, wherein the colorant comprises at least one white pigment.

[0439] Embodiment 29 The inkjet ink formulation of Embodiment 28, wherein the at least one white pigment is TiO2.

[0440] Embodiment 30 The inkjet ink formulation of any one of Embodiments 1 to 29, wherein the colorant constitutes at least 1.0% w / w of the formulation.

[0441] Embodiment 31 The inkjet ink formulation of any one of Embodiments 2 to 30, wherein the at least one binder is an anionic binder.

[0442] Embodiment 32 The inkjet ink formulation of embodiment 31, wherein the anionic binder is an acrylic binder and / or a sulfonic acid binder.

[0443] Embodiment 33 The inkjet ink formulation of any one of Embodiments 2 to 32, wherein the at least one binder is an organic polymer resin.

[0444] Embodiment 34 The inkjet ink formulation of embodiment 33, wherein the organic polymer resin is a negatively charged organic polymer resin.

[0445] Embodiment 35 An inkjet ink formulation as described in any one of Embodiments 2 to 34, wherein the at least one binder is present in the formulation at a concentration between about 5.0 w / w % and about 15.0 w / w %.

[0446] Embodiment 36 A method for preventing or minimizing printhead degradation, the method comprising utilizing a water-based inkjet ink formulation, wherein the formulation comprises at least one alkali metal organosiliconate having formula (I)

[0447]

[0448] in:

[0449] R is a C1-C5 alkyl group;

[0450] M1, M2 and M3 are each independently selected from hydrogen or a cation of an alkali metal, wherein at least one of said M1, M2 and M3 is a cation of an alkali metal, thereby preventing or minimizing print head degradation, and wherein said water-based inkjet ink formulation further comprises a solvent comprising water and at least one colorant.

[0451] Embodiment 37 A method according to Embodiment 36, wherein the water-based inkjet ink formulation further comprises at least one binder.

[0452] Embodiment 38 A method as described in Embodiment 36 or 37, wherein R is a linear or branched C1-C5 alkyl group.

[0453] Embodiment 39 The method of any one of Embodiments 36 to 38, wherein R is a substituted or unsubstituted C1-C5 alkyl.

[0454] Embodiment 40 A method as described in any one of Embodiments 36 to 39, wherein R is a substituted C1-C5 alkyl.

[0455] Embodiment 41 A method as described in Embodiment 40, wherein R is a substituted C1-C5 alkyl group, and wherein the substituent is a polar group selected to increase the solubility of the alkali metal organosilanol salt in water.

[0456] Embodiment 42 A method as described in Embodiment 41, wherein the polar substituent is a hydroxyl group.

[0457] Embodiment 43 A method as described in any one of Embodiments 36 to 42, wherein R is a C1-C3 alkyl group.

[0458] Embodiment 44 is a method as described in Embodiment 43, wherein R is selected from methyl, ethyl, propyl or isopropyl.

[0459] Embodiment 45 is a method as described in Embodiment 44, wherein R is methyl.

[0460] Embodiment 46 A method as described in any one of Embodiments 36 to 45, wherein two of the M1, M2 and M3 are hydrogen and the third is a cation of an alkali metal.

[0461] Embodiment 47 A method as described in any one of Embodiments 36 to 46, wherein the cation of the alkali metal is selected from Li + 、Na + , K + , Rb + , Cs + or any combination thereof.

[0462] Embodiment 48 The method of any one of Embodiments 36 to 47, wherein the cation of the alkali metal is selected from Li + 、Na + , K + or any combination thereof.

[0463] Embodiment 49: The method of any one of Embodiments 36 to 48, wherein the cation of the alkali metal is Na + .

[0464] Embodiment 50: A method as described in any one of Embodiments 36 to 48, wherein the cation of the alkali metal is K + .

[0465] Embodiment 51 A method as described in any one of Embodiments 36 to 48, wherein the cation of the alkali metal is Li + .

[0466] Embodiment 52: The method of any one of Embodiments 36 to 51, wherein R is methyl and wherein the at least one alkali metal organosiliconate is selected from the group consisting of:

[0467]

[0468] Embodiment 53 A method according to Embodiment 52, wherein the at least one alkali metal organosiliconate is

[0469] Embodiment 54 A method according to Embodiment 52, wherein the at least one alkali metal organosilanol salt is

[0470] Embodiment 55 A method according to Embodiment 52, wherein the at least one alkali metal organosilanol salt is

[0471] Embodiment 56 A method according to Embodiment 52, wherein the at least one alkali metal organosilanol salt is

[0472] Embodiment 57 The method of any one of Embodiments 36 to 56, wherein the formulation is free of one or more inorganic silicates.

[0473] Embodiment 58 The method of any one of Embodiments 36 to 57, wherein the formulation is free of silicone.

[0474] Embodiment 59 The method of any one of Embodiments 36 to 58, wherein the at least one alkali metal organosilanol salt is present in the formulation at a concentration of at least about 0.01 w / w %.

[0475] Embodiment 60 A method as described in any one of Embodiments 36 to 59, wherein the at least one alkali metal organosiliconate is present in the formulation at a concentration of about 0.1 w / w % or at least about 0.1 w / w %.

[0476] Embodiment 61 A method as described in any one of Embodiments 36 to 58, wherein the at least one alkali metal organosilanol salt is present in the formulation at a concentration between about 0.01 w / w % and about 1.0 w / w %.

[0477] Embodiment 62 A method as described in any one of Embodiments 36 to 58, wherein the at least one alkali metal organosilanol salt is present in the formulation at a concentration between about 0.1 w / w % and about 0.5 w / w %.

[0478] Embodiment 63 A method as described in any of Embodiments 36 to 62, wherein the colorant includes at least one white pigment.

[0479] Embodiment 64 A method as described in Embodiment 63, wherein the at least one pigment is TiO2.

[0480] Embodiment 65 A method as described in any one of embodiments 36 to 64, wherein the colorant constitutes at least 1.0% w / w of the formulation.

[0481] Embodiment 66 A method as described in any of Embodiments 37 to 65, wherein the at least one binder is an anionic binder.

[0482] Embodiment 67 A method as described in Embodiment 66, wherein the anionic binder is an acrylic binder and / or a sulfonic acid binder.

[0483] Embodiment 68 The method of any one of Embodiments 37 to 67, wherein the at least one binder is an organic polymer resin.

[0484] Embodiment 69 The method of Embodiment 68, wherein the organic polymer resin is a negatively charged organic polymer resin.

[0485] Embodiment 70 A method as described in any one of Embodiments 37 to 69, wherein the at least one binder is present in the formulation at a concentration between about 5.0 w / w % and about 15.0 w / w %.

[0486] Embodiment 71 A method as described in any of Embodiments 36 to 70, wherein the preventing or minimizing degradation of the print head is preventing or minimizing degradation of at least a portion of the print head.

[0487] Embodiment 72 The method of any one of Embodiments 36 to 71, wherein the preventing or minimizing print head degradation is preventing or minimizing degradation of at least a portion of a print head nozzle plate.

[0488] Embodiment 73 A method as described in any of Embodiments 36 to 72, wherein the preventing or minimizing degradation of the print head is inhibiting degradation of the print head.

[0489] Embodiment 74 is a method as described in Embodiment 73, wherein suppressing degradation of the print head is suppressing degradation of liquid repellency properties of the print head.

[0490] Embodiment 75 The method of any one of Embodiments 36 to 74, wherein the preventing or minimizing printhead degradation provides improved compatibility of the inkjet ink formulation with the printhead.

[0491] Embodiment 76 A method as described in any of Embodiments 36 to 75, wherein the print head degradation is erosion.

[0492] Embodiment 77 A method as in Embodiment 76, wherein the erosion is caused by the inkjet ink formulation.

[0493] Embodiment 78 The method of any one of Embodiments 36 to 77, wherein the print head degradation may be chemical damage.

[0494] Embodiment 79 A method as described in any of Embodiments 36 to 78, wherein preventing or minimizing print head degradation increases the life of the print head.

[0495] Embodiment 80 A method as described in Embodiment 79, wherein the life of the printing head is extended by at least 10 times.

[0496] Embodiment 81 A method as described in Embodiment 79, wherein the life of the printing head is extended at least 100 times.

[0497] Embodiment 82 A method as described in any of Embodiments 36 to 81, wherein the print head is used in an inkjet printing process, which is a direct or indirect printing process.

[0498] Embodiment 83 is a method as described in any one of embodiments 36 to 82, wherein in the method, the printing quality is maintained for a long time.

[0499] Embodiment 84 A method as described in any of Embodiments 36 to 83, wherein the print head forms part of a printing system.

[0500] Embodiment 85 A method as described in Embodiment 84, wherein the system is a direct or indirect printing system.

[0501] Embodiment 86 The method of any one of Embodiments 36 to 85, wherein at least a portion of the print head is formed from a metal oxide.

[0502] Embodiment 87 A method as described in Embodiment 86, wherein the metal oxide is silicon oxide.

[0503] Embodiment 88 A method as described in Embodiment 87, wherein the silicon oxide is thermally grown silicon oxide.

[0504] Embodiment 89 A method as described in Embodiment 88, wherein the thermally grown silicon oxide is coated with a liquid-repellent film comprising a fluoroalkylsilane moiety.

[0505] Embodiment 90 A method according to Embodiment 89, wherein the liquid repellent membrane comprising a fluoroalkylsilane moiety is formed by using a n F 2n+1 -C m H 2m -Si-X3, wherein n represents an integer of 1 or more; m represents an integer of 0 or more; X represents an alkoxy group, an amino group or a halogen atom; and a part of X may be substituted with an alkyl group.

[0506] Embodiment 91 A method according to embodiment 90, wherein the compound is C8F 17 C2H4SiCl3.

[0507] Embodiment 92 A method as described in Embodiment 90 or 91, wherein the liquid-repellent film is provided on the surface of the ink print head nozzle.

[0508] Embodiment 93 A method as described in Embodiment 92, wherein the liquid-repellent film is provided on the surface of the inkjet print head nozzle on the side facing the ink ejection direction of the nozzle.

[0509] Embodiment 94 A water-based inkjet ink formulation for preventing or minimizing print head degradation according to any one of Embodiments 1 to 35.

[0510] Embodiment 95 A water-based inkjet ink formulation for use in a printing process according to any one of embodiments 1 to 35.

[0511] Embodiment 96 A water-based inkjet ink formulation according to any one of embodiments 1 to 35, which forms part of a printing system.

[0512] Embodiment 97 A printing method, the printing method using the water-based inkjet ink formulation according to any one of embodiments 1 to 35.

[0513] Embodiment 98 A printing system comprising the water-based inkjet ink formulation according to any one of Embodiments 1 to 35.

[0514] Embodiment 99 A printing system, the printing system comprising an image forming station, the image forming station comprising one or more printing bars, each of the one or more printing bars being configured to hold an ink formulation and comprising one or more print heads, each of the one or more print heads being configured to eject the ink formulation onto a printing substrate to form an ink image on the substrate, wherein at least one of the one or more printing bars is configured to hold a water-based inkjet ink formulation according to any one of Embodiments 1 to 35.

[0515] Embodiment 100 A printing system, comprising:

[0516] an intermediate transfer member including a release layer surface;

[0517] an image forming station comprising one or more printing bars, each of the one or more printing bars being configured to hold an ink formulation and comprising one or more print heads, each of the one or more print heads being configured to eject the ink formulation onto the release layer surface to form an ink image thereon, wherein at least one of the one or more printing bars is configured to hold the water-based inkjet ink formulation according to any one of embodiments 1 to 35; and

[0518] A transfer station is provided for transferring the ink image from the intermediate transfer member to a printing substrate.

[0519] Embodiment 101 A system as described in Embodiment 100, wherein the system also includes a drying station configured to substantially dry the ink image formed on the intermediate transfer member, and wherein the transfer station is configured to transfer the substantially dried ink image from the intermediate transfer member to a printing substrate.

[0520] Embodiment 102 is a system as described in any of Embodiments 99 to 101, wherein the system is substantially as disclosed herein.

[0521] Embodiment 103 A system as described in any of Embodiments 99 to 101, wherein at least a portion of the one or more print heads is formed from a metal oxide.

[0522] Embodiment 104 A system as described in Embodiment 103, wherein the metal oxide is silicon oxide.

[0523] Embodiment 105 A system as described in Embodiment 104, wherein the silicon oxide is thermally grown silicon oxide.

[0524] Embodiment 106 A system as described in Embodiment 105, wherein the thermally grown silicon oxide is coated with a liquid-repellent film comprising a fluoroalkylsilane moiety.

[0525] Embodiment 107 A system as described in Embodiment 106, wherein the liquid-repellent membrane comprising a fluoroalkylsilane moiety is formed by using a n F 2n+1 -C m H 2m -Si-X3, wherein n represents an integer of 1 or more; m represents an integer of 0 or more; X represents an alkoxy group, an amino group or a halogen atom; and a part of X may be substituted with an alkyl group.

[0526] Embodiment 108 A system as described in Embodiment 107, wherein the compound is C8F 17 C2H4SiCl3.

[0527] Embodiment 109 The system of any of Embodiments 99 to 108, wherein the liquid-repellent membrane is provided on the surface of the one or more print head nozzles.

[0528] Embodiment 110 A system as described in Embodiment 109, wherein the liquid-repellent film is provided on the surface of the one or more print head nozzles on a side facing the ink ejection direction of the nozzles.

[0529] Embodiment 111 A system as described in any of Embodiments 100 to 110, wherein the intermediate transfer member is substantially as disclosed herein.

[0530] Embodiment 112 A system as described in any of Embodiments 100 to 111, wherein the transfer station is substantially as disclosed herein.

[0531] Embodiment 113 A system as described in any of Embodiments 101 to 112, wherein the drying station is substantially as disclosed herein.

[0532] Embodiment 114 A system as described in any of Embodiments 99 to 113, wherein the printing substrate is substantially as disclosed herein.

Claims

1. A water-based inkjet ink formulation, comprising: (a) a solvent containing water; (b) at least one colorant; and (c) at least one alkali metal organosilanol salt having the formula (I) in: R is a C1-C5 alkyl group which may be substituted; M1, M2 and M3 are each independently selected from hydrogen or a cation of an alkali metal, wherein at least one of M1, M2 and M3 is a cation of an alkali metal, and wherein the at least one alkali metal organosiliconate is present in the formulation at a concentration of at least 0.1 w / w %.

2. The inkjet ink formulation according to claim 1, further comprising at least one binder.

3. The inkjet ink formulation according to claim 1 or 2, wherein R is selected from methyl, ethyl, propyl or isopropyl.

4. The inkjet ink formulation according to claim 1 or 2, wherein two of the M1, M2 and M3 are hydrogen and the third is a cation of an alkali metal.

5. The inkjet ink formulation according to claim 1 or 2, wherein R is methyl and wherein the at least one alkali metal organosilanolate is selected from the group consisting of:

6. The inkjet ink formulation according to claim 1 or 2, wherein the formulation is free of one or more inorganic silicates and / or free of silica gel.

7. The inkjet ink formulation according to claim 1 or 2, wherein the colorant comprises at least one white pigment.

8. The inkjet ink formulation according to claim 1 or 2, wherein the at least one alkali metal organosiliconate is present in the formulation at a concentration between 0.1 w / w % and 1.0 w / w %.

9. The inkjet ink formulation according to claim 1 or 2, wherein the at least one alkali metal organosiliconate is present in the formulation at a concentration between 0.1 w / w % and 0.5 w / w %.

10. A method for preventing or minimizing printhead degradation, the method comprising utilizing a water-based inkjet ink formulation, wherein the formulation comprises at least one alkali metal organosiliconate having formula (I) in: R is a C1-C5 alkyl group which may be substituted; M1, M2 and M3 are each independently selected from hydrogen or a cation of an alkali metal, wherein at least one of M1, M2 and M3 is a cation of an alkali metal; wherein the at least one alkali metal organosiliconate is present in the formulation at a concentration of at least 0.1 w / w % thereby preventing or minimizing printhead degradation; and The water-based inkjet ink formulation further comprises a solvent including water and at least one colorant.

11. The method of claim 10, wherein the water-based inkjet ink formulation further comprises at least one binder.

12. The method according to claim 10 or 11, wherein R is selected from methyl, ethyl, propyl or isopropyl.

13. The method according to claim 10 or 11, wherein two of the M1, M2 and M3 are hydrogen and the third is a cation of an alkali metal.

14. The method according to claim 10 or 11, wherein R is methyl and wherein the at least one alkali metal organosilanolate is selected from the group consisting of:

15. The method of claim 10 or 11, wherein the formulation is free of one or more inorganic silicates and / or free of silica gel.

16. The method of claim 10 or 11, wherein the colorant comprises at least one white pigment.

17. The method according to claim 10 or 11, wherein the preventing or minimizing print head degradation is suppressing degradation of the print head, wherein the suppressing degradation of the print head is suppressing degradation of a liquid repellent property of the print head.

18. A method according to claim 10 or 11, wherein the print head forms part of a printing system, the printing system being a direct or indirect printing system.

19. The method of claim 10 or 11, wherein at least a portion of the print head is formed from a metal oxide.

20. The method according to claim 19, wherein the metal oxide is thermally grown silicon oxide coated with a liquid repellent film containing a fluoroalkylsilane moiety, and wherein the liquid repellent film is provided on a surface of an inkjet print head nozzle on a side toward an ink ejection direction of the nozzle.

21. The method of claim 10 or 11, wherein the at least one alkali metal organosiliconate is present in the formulation at a concentration between 0.1 w / w % and 1.0 w / w %.

22. The method of claim 10 or 11, wherein the at least one alkali metal organosiliconate is present in the formulation at a concentration between 0.1 w / w % and 0.5 w / w %.

23. A printing method utilizing the water-based inkjet ink formulation according to any one of claims 1 to 9.

24. A printing system comprising the water-based inkjet ink formulation according to any one of claims 1 to 9.

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