Water-based ink, inkjet recording method, ink cartridge, recording unit, and inkjet recording apparatus
9 claims: 7 independent, 2 dependent
- 1熱エネルギーの作用により記録ヘッドからインクを吐出するインクジェット記録方法に用いる、顔料、前記顔料を分散するための樹脂、及び水溶性有機溶剤を含有してなる水性インクであって、 前記顔料は、C.I.ピグメントバイオレット23であり、 前記顔料を分散するための樹脂は、その重量平均分子量が2,000以上5,000以下であり 、 前 記水溶性有機溶剤のインク中における含有量が、インク全質量を基準として、5.0質量%以上17.5質量%以下であ り、 かつ、前記水溶性有機溶剤が、重量平均分子量が1,000以上のポリエチレングリコールを含む ことを特徴とする水性インク。
- 2前記樹脂が、ブロックポリマーである請求項1に記載の水性インク。
- 3前記水溶性有機溶剤は、グリセリン、エチレングリコール、ジエチレングリコール 、及 び、2-ピロリドンからなる群より選ばれる少なくとも1種を含む請求項1又は2に記載の水性インク。
- 4さらに、インクの吸光特性が、波長530nm以上540nm以下の範囲と、波長550nm以上570nm以下の範囲にそれぞれ極大吸収波長を持ち、 前記波長530nm以上540nm以下の範囲にある極大吸収波長における吸光度(A)と、前記波長550nm以上570nm以下の範囲にある極大吸収波長における吸光度(B)との関係が、下記式(1)の条件を満たすものである請求項1乃至 3 のいずれか1項に記載の水性インク。
- 5前記インクの吸光特性が、さらに、波長530nm以上540nm以下の範囲と、波長620nm以上630nm以下の範囲にそれぞれ極大吸収波長を持ち、 前記波長530nm以上540nm以下の範囲にある極大吸収波長における吸光度(A)と、前記波長620nm以上630nm以下の範囲にある極大吸収波長における吸光度(C)との関係が下記式(2)の条件を満たす請求項 4 に記載の水性インク。
- 6熱エネルギーの作用によりインクを吐出して記録媒体に記録を行うインクジェット記録方法において、前記インクが、請求項1乃至 5 のいずれか1項に記載の水性インクであることを特徴とするインクジェット記録方法。
- 7インクを収容するインク収容部を備えたインクカートリッジにおいて、前記インクが、請求項1乃至 5 のいずれか1項に記載の水性インクであることを特徴とするインクカートリッジ。
- 8インクを収容するインク収容部と、熱エネルギーの作用によりインクを吐出するための記録ヘッドとを備えた記録ユニットにおいて、前記インクが、請求項1乃至 5 のいずれか1項に記載の水性インクであることを特徴とする記録ユニット。
- 9インクを収容するインク収容部と、熱エネルギーの作用によりインクを吐出するための記録ヘッドとを備えたインクジェット記録装置において、前記インクが、請求項1乃至 5 のいずれか1項に記載の水性インクであることを特徴とするインクジェット記録装置。
Independent claims9
122 paragraphs, as filed
The present invention relates to a water-based ink containing a pigment dispersed in a resin, and further relates to an inkjet recording method using the ink, an ink cartridge, a recording unit, and an inkjet recording device.
It is well known that a water-based ink (pigment ink) containing a pigment is used as a coloring material in order to improve the light resistance, gas resistance, water resistance, etc. of the image obtained by the inkjet recording method. .. Recently, since the type of pigment affects the light resistance and gas resistance of the obtained image, it has been related to selecting a pigment capable of giving excellent light resistance and gas resistance and using it in a pigment ink. There is a proposal (see Patent Document 1).
However, compared to ink containing a dye as a coloring material (dye ink), pigment ink has a problem that it is more likely to cause clogging at the tip of a nozzle or in an ink flow path due to evaporation of water from a discharge port. .. In response to this problem, there are many proposals for devising the type of water-soluble organic solvent used for ink and defining the characteristics of pigments or resins (dispersants) that disperse pigments (see Patent Documents 2 and 3). ).
<patcit num="1"><text>Japanese Unexamined Patent Publication No. 2004-217765</text></patcit><patcit num="2"><text>Japanese Unexamined Patent Publication No. 9-194780</text></patcit><patcit num="3"><text>Japanese Unexamined Patent Publication No. 2003-147243</text></patcit>
<p num="0005"> The present inventors have conducted the following studies for the purpose of providing a pigment ink having excellent reliability (storage stability and ejection stability) and further excellent image quality (fixability and marker resistance). went. That is, as a coloring material, a plurality of inks each containing various resin-dispersed pigments (pigments dispersed by a resin) having different surface treatments of the pigments were prepared. Then, the reliability was evaluated by ejecting these inks using an inkjet recording device. In this study, a thermal type inkjet recording device that ejects ink by the action of thermal energy was used. As a result, it was found that some of the evaluated inks did not have ejection characteristics (frequency response, stable ejection volume, ejection speed, etc.). In particular, as will be described later, it has been found that this tendency is observed in an ink containing a resin-dispersed pigment in which a pigment having a hydrophilicity δm in the range of 21.5 or more and 23.5 or less is dispersed with a resin.</p><p num="0006"> Furthermore, the present inventors have caused the above-mentioned difference in discharge characteristics not to be the conventionally known clogging that occurs at the discharge port (orifice), but to a new phenomenon described below. It was confirmed. That is, when ink is continuously ejected from the recording head, deposits adhere to the inside of the ink flow path and the vicinity of the ejection port, and the ink flow path is blocked, which makes it impossible to obtain sufficient ejection stability. It turned out that there is.</p><p num="0007"> Therefore, an object of the present invention is to provide an ink containing a pigment dispersed in a resin, which can obtain good ejection stability when used in an inkjet recording method for ejecting ink by the action of thermal energy. To do. Another object of the present invention is to allow the ink cartridge containing the ink to be normally ejected from the recording head by performing a predetermined recovery operation even after the ink cartridge containing the ink is attached to the recording head and left for a long period of time. The purpose is to provide ink with excellent reliability. Furthermore, another object of the present invention is to provide an inkjet recording method, an ink cartridge, a recording unit, and an inkjet recording device using the ink.</p>
<p num="0008"> The above object is achieved by the following invention. That is, the ink of the present invention is a water-based ink containing a pigment, a resin for dispersing the pigment, and a water-soluble organic solvent used in an inkjet recording method for ejecting ink from a recording head by the action of heat energy. The pigment is CI Pigment Violet 23, and the resin for dispersing the pigment has a weight average molecular weight of 2,000 or more and 5,000 or less.<u style="single">,Before</u>The content of the water-soluble organic solvent in the ink is 5.0% by mass or more and 17.5% by mass or less based on the total mass of the ink.<u style="single">Moreover, the water-soluble organic solvent contains polyethylene glycol having a weight average molecular weight of 1,000 or more.</u>It is characterized by that.</p><p num="0010"> Also, another form of ink of the present invention<u style="single">,further</u>The absorption characteristics of the ink have maximum absorption wavelengths in the wavelength range of 530 nm or more and 540 nm or less and the wavelength range of 550 nm or more and 570 nm or less, respectively, and the absorbance (A) at the maximum absorption wavelength in the wavelength range of 530 nm or more and 540 nm or less. The relationship with the absorbance (B) at the maximum absorption wavelength in the wavelength range of 550 nm or more and 570 nm or less satisfies the condition of the following formula (1).<img id="000002" he="13" wi="151" file="JP5241110B2_D0001.tif" img-format="tif" img-content="drawing" /></p><p num="0011"> Further, the inkjet recording method according to another embodiment of the present invention is characterized in that any of the above inks is used in the inkjet recording method in which ink is ejected by the action of heat energy to record on a recording medium.</p><p num="0012"> Further, the ink cartridge according to another embodiment of the present invention is an ink cartridge provided with an ink accommodating portion for accommodating ink, and the ink contained is one of the above inks.</p><p num="0013"> Further, the recording unit according to another embodiment of the present invention is a recording unit including an ink accommodating portion for accommodating ink and a recording head for ejecting ink by the action of thermal energy. It is characterized by being any of the above-mentioned inks.</p><p num="0014"> Further, the inkjet recording device according to another embodiment of the present invention is housed in an inkjet recording device including an ink accommodating portion for accommodating ink and a recording head for ejecting ink by the action of thermal energy. The ink is one of the above-mentioned inks.</p>
<p num="0015"> According to the present invention, although it is a water-based pigment ink containing a pigment dispersed in a resin (hereinafter, also referred to as ink), it has good ejection stability when used for inkjet recording of a method of ejecting ink by the action of thermal energy. It is possible to provide an ink having a property. In addition, even after the ink cartridge containing such ink is attached to the recording head and left for a long period of time, the ink can be normally ejected from the recording head by performing a predetermined recovery operation, which is also excellent in reliability. Ink can be provided. Furthermore, it is possible to provide an inkjet recording method, an ink cartridge, a recording unit, and an inkjet recording apparatus using the ink capable of stably forming an image.</p>
Hereinafter, the present invention will be described in detail with reference to preferred embodiments. In the process of studying to solve the above-mentioned problems, the present inventors first determine the hydrophilicity of the pigment δm and the deposits generated in the ink flow path and the vicinity of the ejection port of the thermal type inkjet recording device. We found that there was a large correlation with. That is, when ink containing a resin-dispersed pigment in which a pigment having a hydrophilicity δm in the range of 21.5 or more and 23.5 or less is dispersed with a resin is continuously ejected, it is deposited in the ink flow path and in the vicinity of the ejection port. It was found that the thing was particularly noticeable. Therefore, the present inventors can obtain good ejection characteristics even when a resin-dispersed pigment in which a pigment having the above-mentioned surface characteristics (hydrophilicity δm) is dispersed with a resin is used. Further studies were conducted with the aim of providing highly potent inks.
[History of invention] (Existence of issues) First, the background to the present invention will be described in detail. The present inventors can stably give an image that can satisfy higher light resistance, gas resistance, water resistance, scratch resistance, etc. as compared with conventional inkjet inks. A study was conducted for the purpose of providing a water-based ink containing a dispersed pigment. As a result, when ink containing a resin-dispersed pigment in which a pigment having a hydrophilicity δm in the range of 21.5 or more and 23.5 or less is dispersed with a resin is continuously ejected using a thermal type inkjet recording device, the following It was found that the unfavorable phenomenon of That is, in this case, it was confirmed that deposits adhered in the ink flow path and in the vicinity of the ejection port, and that the deposits lowered the ejection stability. Therefore, as a result of pursuing the cause of such a phenomenon, the present inventors have noticed the following phenomenon when the resin-dispersed pigment as described above and the thermal type inkjet recording method are combined. I came to the conclusion that it would happen.
(Mechanism of sediment generation) FIG. 1 is a schematic view showing the mechanism of deposit generation in the vicinity of the discharge port when a thermal type inkjet recording device is used. In FIG. 1, (a) is a state in which film-like bubbles 6 are formed on the heater 1. In addition, (b) to (h) are (b) about 1 μs, (c) about 2.5 μs, (d) about 3 μs, and (e) about 4 μs, respectively, from the state of (a). After that, (f) after about 4.5 μsec, (g) after about 6 μsec, and (h) after about 9 μsec are shown. The horizontally hatched portions in FIGS. 1 (a) to 1 (h) indicate the orifice plate or the flow path wall.
First, as shown in FIG. 1A, bubbles 6 are generated inside the ink flow path 2 on the heater 1 as the heater 1 is energized based on a recording signal or the like. At this time, the temperature of the ink near the heater 1 rises to about 200 ° C. Then, in the ink whose temperature has risen, dispersion destruction of the pigment dispersion occurs, and phenomena such as desorption of the dispersant (resin) from the pigment and fragmentation of the pigment occur. As a result, the pigment whose dispersion state is unstable is present in the ink in a mixed state. At this time, dispersion fracture occurs when the adsorptive force of the resin to the pigment is particularly weak, or when the amount of resin required for the pigment to maintain a stable dispersed state is not adsorbed on the pigment. Most of the pigments in which the pigment is insufficiently dispersed are in the following states. That is, phenomena such as desorption of the resin from the pigment, fragmentation of the pigment, and further change to a state in which the resin is dissolved in the ink occur rapidly and excessively, so that the dispersed state becomes unstable. There will be many pigments.
Then, as shown in FIGS. 1 (b) and 1 (c), the volume of the bubble 6 rapidly expands in about 2.5 μsec. Along with this, the ink whose temperature has risen is cooled. As the temperature of the ink decreases, the pigment whose dispersed state has become unstable cannot maintain the dispersed state, agglutination of the pigment occurs, and pigments precipitated in the ink appear. A part of the pigment agglomerates 4 precipitated in this way is ejected from the ejection port 3 in a state of being contained in the ink droplets 5, but remains inside the ink flow path 2 and flows. Some adhere to the road wall. By repeating the ink ejection shown in FIGS. 1 (a) to 1 (h) in this way, it is considered that the agglomerates 4 deposited in the ink are deposited on the flow path wall.
The present inventors are prone to dispersion destruction of pigments in inks containing resin-dispersed pigments in which pigments having a hydrophilicity δm of 21.5 or more and 23.5 or less are dispersed with a resin, and the generated deposits reduce ejection stability. The cause of this problem is presumed as follows. First, it is considered that the biggest reason why such ink specifically increases the adhesion of deposits in the ink flow path and in the vicinity of the ejection port as compared with other pigment inks is that the resin has a weak adsorption force to the pigment. ing. That is, since the pigment having a hydrophilicity δm of 21.5 or more has a relatively high hydrophilicity, the resin functioning as a dispersant is easily desorbed from the pigment surface. Therefore, when the ink is ejected from the recording head by the action of thermal energy as described above when the ink is ejected, the dispersion destruction due to heat proceeds easily and rapidly. As a result, it is estimated that deposits are generated in the ink flow path and in the vicinity of the ejection port.
In contrast to the above, the present inventors use an ink containing a resin-dispersed pigment in which a pigment having a hydrophilicity of more than 23.5 is dispersed with a resin, and the ink is deposited in the ink flow path and in the vicinity of the ejection port. It was confirmed that the adhesion of substances was suppressed. As described above, when an ink containing a resin-dispersed pigment having a hydrophilicity of more than 23.5 is used, the reason why the adhesion of deposits is reduced is not clear, but the present inventors speculate as follows. ing. That is, even when a pigment having a hydrophilicity of more than 23.5 is dispersed in the resin, the resin remains difficult to be adsorbed on the pigment surface. However, since the hydrophilicity δm of the pigment greatly increases the hydrophilicity of the pigment itself at the boundary of 23.5, even if the dispersion destruction of the pigment dispersion progresses due to the heat at the time of discharge, the generated dispersion destruction product is also highly water-soluble. It is possible to keep the. As a result, when an ink containing a resin-dispersed pigment having a hydrophilicity of more than 23.5 is used, the generated dispersed debris is discharged out of the ink flow path together with the ink without precipitating, and is inside the ink flow path. It is considered that almost no deposits adhere to the vicinity of the discharge port.
[Solution] From the above, the present inventors can suppress dispersion destruction due to heat at the time of ejection as much as possible even when a resin-dispersed pigment in which a pigment having a hydrophilicity δm of 21.5 or more and 23.5 or less is dispersed with a resin is used. The study was conducted for the purpose of providing ink. As a result, it was found that there are two kinds of methods for solving the above-mentioned problems, and the present invention was reached. The two types of methods that can solve the above-mentioned problems of the present invention will be described below.
(First method) The first method for solving the problem of the present invention is the content of a water-soluble organic solvent in an ink containing a resin-dispersed pigment in which a pigment having a hydrophilicity δm of 21.5 or more and 23.5 or less is dispersed with a resin ( Mass%) is a method of optimizing. Specifically, the content of the water-soluble organic solvent in the ink is adjusted to be 5.0% by mass or more and 17.5% by mass or less based on the total mass of the ink. According to the first method, deposits in the ink flow path and in the vicinity of the ejection port can be effectively reduced regardless of the type of the water-soluble organic solvent. The ink of the first embodiment of the present invention constructed by the first method is hereinafter referred to as "first ink".
As a result of the studies by the present inventors, the following was found regarding the influence of the content of the water-soluble organic solvent in the ink. First, as the content of the water-soluble organic solvent in the ink increases, the affinity between the aqueous medium in the ink and the hydrophobic portion of the resin that functions as a dispersant increases. That is, it was found that as the content of the water-soluble organic solvent increased, the adsorptive power of the resin to the pigment tended to become relatively small. In addition, a highly hydrophilic pigment having a hydrophilicity δm of 21.5 or more has a weak adsorption force between the surface of the pigment and the hydrophobic part of the resin. Therefore, the pigment is compared with other pigments. , It was found that it is particularly susceptible to the influence of water-soluble organic solvents in ink.
Therefore, as a result of further studies by the present inventors, the following was found. That is, even if a highly hydrophilic resin-dispersed pigment having a hydrophilicity δm of 21.5 or more and 23.5 or less is used, if the content of the water-soluble organic solvent in the ink is within a specific range, the pigment dispersion It was found that the dispersion destruction of the ink can be suppressed. Specifically, when the content of the water-soluble organic solvent in the ink is 17.5% by mass or less based on the total mass of the ink, the pigment is compared with the affinity between the aqueous medium and the hydrophobic portion of the resin. The affinity between the hydrophobic part of the surface and the hydrophobic part of the resin is higher. Therefore, it is presumed that by optimizing the content of the water-soluble organic solvent in the ink, it is possible to suppress the dispersion destruction of the pigment dispersion due to the heat at the time of ejection.
Further, as a result of further studies by the present inventors, it has been found that the content of the water-soluble organic solvent needs to be 5.0% by mass or more based on the total mass of the ink. When the content of the water-soluble organic solvent is less than 5.0% by mass, the generation of deposits is suppressed, but the moisturizing property is poor, and pigment precipitation due to water evaporation near the discharge port and clogging of the discharge port are performed. This is because a discharge failure may occur due to the above. The content of the water-soluble organic solvent in the ink is 2.5 times or more and 17.0 times or less (mass ratio) based on the content of the pigment in the ink (content of the water-soluble organic solvent / content of the pigment). It is preferable to have.
(Second method) The second method for solving the problem of the present invention is to absorb the ink by adjusting the dispersion state when CI Pigment Violet 23, which is a pigment having a hydrophilicity δm of 21.5 or more and 23.5 or less, is used. It optimizes the characteristics. According to the second method, deposits in the ink flow path and in the vicinity of the ejection port can be effectively reduced regardless of the type of the water-soluble organic solvent used for the ink. The ink of the second form of the present invention constructed by the second method is hereinafter referred to as "second ink".
The present inventors have selected CI Pigment Violet 23 as an example of a pigment having a hydrophilicity δm of 21.5 or more and 23.5 or less, and using such a pigment, they are excellent in storage stability, ejection stability, color development and the like. The study was conducted for the purpose of obtaining new ink. Specifically, several types of pigment dispersions with different dispersion conditions of CI Pigment Violet 23 were prepared and examined. As a result, it was found that the absorption characteristics of the pigment dispersion are greatly related to the discharge characteristics and the color development property.
The relationship between the absorption characteristics, the dispersion conditions, and the discharge characteristics of CI Pigment Violet 23 will be described below. As shown in FIG. 8, the liquid containing the pigment dispersion of CI Pigment Violet 23 has a maximum absorption wavelength in each of the three wavelength regions of wavelengths 530 nm to 540 nm, 550 nm to 570 nm, and 620 nm to 630 nm.
As a result of the study by the present inventors, it was found that when the dispersion conditions when preparing the pigment dispersion were changed, the ratios of the absorbances at these three maximum absorption wavelengths changed to some extent regularly. Specifically, a pigment dispersion having different dispersion conditions was prepared and examined by changing the type of the disperser, the dispersion time and the peripheral speed, the bead diameter and the type of beads, and the like. Then, by measuring the absorption characteristics of each of these pigment dispersions, the following facts were found.
That is, it was found that when the dispersion conditions were strict, the ratios of absorbances at the above three maximum absorption wavelengths tended to change as follows. First, the ratio [(B) / (A)] of the absorbance (B) at the maximum absorption wavelength in the wavelength range of 550 nm or more and 570 nm to the absorbance (A) at the maximum absorption wavelength in the wavelength range of 530 nm or more and 540 nm or less is , Tend to grow. In addition, the ratio of absorbance (C) at the maximum absorption wavelength in the wavelength range of 620 nm or more and 630 nm to the absorbance (A) at the maximum absorption wavelength in the wavelength range of 530 nm or more and 540 nm [(C) / (A)] , Tend to grow.
Next, the present inventors prepare a plurality of inks by adding a water-soluble organic solvent and water generally used for inkjet inks to a plurality of pigment dispersions of CI pigment violet 23 having different dispersion conditions. did. Then, these inks are mounted on a thermal type inkjet recording device, and the inks are continuously ejected, and the details regarding the relationship with the deposits adhering to the ink flow path and the vicinity of the ejection port described above are described in detail. We conducted a thorough examination. As a result, when the ratio of the absorbance (A) to the absorbance (B) does not satisfy the condition of the following formula (1), a large amount of deposits adhere in the ink flow path and in the vicinity of the ejection port, thereby achieving ejection stability. Was found to occur.<img id="000003" he="13" wi="151" file="JP5241110B2_D0001.tif" img-format="tif" img-content="drawing" /> The reason why the deposits adhere to the ink flow path and the vicinity of the ejection port when the inks whose values of [(B) / (A)] do not satisfy the above range are continuously ejected is not clear. The present inventors speculate as follows.
[When the value of [(B) / (A)] is smaller than 0.93] The liquid (water-based ink) containing the pigment dispersion of CI Pigment Violet 23 having a value of (B) / (A) smaller than 0.93 is in a state where the pigment is insufficiently dispersed. That is, in the liquid containing such a pigment dispersion, there are many coarse particles having cracks on the surface. The larger the proportion of the pigment present in the state of coarse particles, the smaller the specific surface area of the pigment, and therefore the smaller the amount of the resin (dispersant) adsorbed on the pigment surface. Further, in the liquid containing the pigment dispersion, the resin repeatedly absorbs and desorbs from the pigment, that is, the resin is adsorbed on the pigment, or the resin is separated from the pigment and dissolved in the liquid. It is thought to be repeating. As described above, CI Pigment Violet 23 having a hydrophilicity δm of 21.5 or more and 23.5 or less has a high degree of hydrophilicity of the pigment, so that the resin can be easily attached and detached, but the resin is unlikely to be adsorbed. Therefore, it is considered that the pigment in the liquid containing the pigment dispersion of CI Pigment Violet 23 exists in a state where the resin is not sufficiently adsorbed on the pigment surface. In addition, the present inventors, when the value of [(B) / (A)] is 0.93 as a boundary and becomes smaller than this value, the deposits in the ink flow path and in the vicinity of the ejection port are greatly increased. Is confirmed. The reason for this is that the value of [(B) / (A)] is 0.93, and if it is smaller than this, the resin will not be sufficiently adsorbed on the pigment surface, so the heat at the time of discharge will be generated. It is presumed that this is because the dispersion fracture caused by the temperature rise due to the above progressed rapidly.
[When the value of [(B) / (A)] is larger than 0.97] The liquid (water-based ink) containing the pigment dispersion of CI Pigment Violet 23 having a value of [(B) / (A)] greater than 0.97 is in a state of overdispersion of the pigment. That is, in the liquid containing such a pigment dispersion, there are many pigments in a very finely pulverized state. The larger the proportion of pigments with smaller particle sizes, the larger the specific surface area of the pigments. Therefore, it is difficult to maintain a stable dispersed state unless the content of the resin (dispersant) that disperses the pigments is increased. May be. However, in the case of an inkjet ink, the content of the resin in the ink is limited in consideration of reliability. Further, as the particle size of the pigment becomes smaller, the surface energy of the pigment becomes higher, so that the pigments are more likely to aggregate with each other. Further, as described above, CI Pigment Violet 23 having a hydrophilicity δm of 21.5 or more and 23.5 or less is considered to be less likely to cause resin adsorption because the pigment has high hydrophilicity. For the above reasons, the proportion of the resin that should function as a dispersant adsorbed on the surface of the particles of CI pigment violet 23 in the overdispersed state becomes small. Therefore, it may be difficult to maintain a stable dispersed state even with a slight change in the environment. As a result, when the ink containing the pigment dispersion is ejected using a thermal type inkjet recording device, deposits are generated in the ink flow path and in the vicinity of the ejection port by the mechanism described above. Conceivable.
As a result of further studies by the present inventors, when the value of [(B) / (A)] is 0.97 and becomes larger than this, the deposits in the ink flow path and near the ejection port are particularly high. It turned out to increase. This is because there are many pigment dispersions in which it is difficult to maintain a stable dispersed state even with slight environmental changes when the values of (B) / (A) are greater than 0.97. It is presumed that the dispersion destruction due to the temperature rise due to the heat at the time of discharge progresses rapidly. Further, a pigment having a high surface energy is likely to generate deposits due to various portions in the flow path from the ink cartridge containing the ink to the recording head for ejecting the ink. Then, it is considered that the adhesion of the re-aggregate of the pigment centering on the deposit is remarkably promoted.
As far as the present inventors have examined, the above-mentioned value of [(B) / (A)] in the liquid containing the pigment dispersion of CI Pigment Violet 23 commercially available for inkjet is larger than 0.97. I understood it. The reason for this is not clear, but the present inventors speculate as follows. The larger the value of [(B) / (A)] in the liquid containing the pigment dispersion of CI Pigment Violet 23, the better the color development. On the other hand, the deposits generated in the ink flow path and the vicinity of the ejection port as described above and the deterioration of the ejection characteristics due to such deposits occur specifically only when the ink is ejected using the thermal type inkjet recording device. It can be said that it is an issue to be done. In other words, CI Pigment Violet 23, which is commercially available for inkjet, does not take into consideration the ejection characteristics, and the value of [(B) / (A)] is 0.97 only for the purpose of further improving the color development property. It is thought that it is getting bigger. As described above, even when such a commercially available CI pigment violet 23 is used, the present invention defines it by appropriately determining the dispersion conditions of the pigment [(B) / (A)]. An ink containing a pigment dispersion having the above range can be obtained.
As described above, the absorbance (A) at the maximum absorption wavelength in the wavelength range of 530 to 540 nm and the absorbance (B) at the maximum absorption wavelength in the wavelength range of 550 to 570 nm play a major role in the generation of sediments. The ratio of [(B) / (A)]. Further, as described above, the liquid containing the pigment dispersion of CI Pigment Violet 23 has a maximum absorption wavelength in the wavelength range of 620 nm or more and 630 nm or less in addition to the above two ranges (absorbance (C). )). The ratio of absorbance at these three maximum absorption wavelengths changes to some extent regularly by changing the dispersion conditions when preparing the pigment dispersion. Therefore, the present inventors have stated that the absorbance (C) at the maximum absorption wavelength in the wavelength range of 620 nm or more and 630 nm or less also has a considerable influence on the color development property and the generation of deposits in the ink flow path and in the vicinity of the ejection port. I thought about it and examined it further. As a result, the liquid containing the pigment dispersion satisfying the condition of the above formula (1) and further satisfying the condition of the following formula (2) is compared with the pigment dispersion satisfying only the condition of the formula (1). It was found that the generation of deposits in the ink flow path and in the vicinity of the ejection port can be suppressed more effectively.<img id="000004" he="13" wi="151" file="JP5241110B2_D0001.tif" img-format="tif" img-content="drawing" />
Further, according to the study by the present inventors, the maximum absorption wavelengths that give the above-mentioned absorbances (A), (B) and (C) are present in the following wavelength ranges, respectively, in the ink flow path. It was also found that the generation of deposits near the discharge port can be suppressed particularly effectively. That is, the absorbance (A) exists within the wavelength range of 533.0 nm or more and 535.0 nm or less, the absorbance (B) exists within the wavelength range of 562.0 nm or more and 562.5 nm or less, and the absorbance (C) exists within the wavelength range of 624.5 nm or more and 625.0 nm or less. Is preferable. By appropriately determining the dispersion conditions of the pigment in the same manner as described above, the wavelengths in which the maximum absorption wavelengths that give the absorbances (A), (B), and (C) exist are present in the above ranges, respectively. An ink containing a pigment dispersion can be obtained.
(Hydrophilicity of pigment δm) Here, a method for calculating the hydrophilicity δm of the pigment will be described. The hydrophilicity δm of the pigment in the present invention is a value calculated according to the acetone titration method described below described in Coloring Material [62 [8], 524-528 (1989)]. First, 0.1 g of pigment is added to a beaker containing a stirrer and 50 ml of ion-exchanged water, and the mixture is gently stirred to the extent that no vortex is formed. Here, acetone is added dropwise using a burette under stirring. Then, let A be the amount of acetone dropped until the floating pigment gets wet and settles. Using the value of A, the hydrophilicity δm of the pigment is calculated from the following formula (3). The values of 23.43 and 9.75 in the following formula (3) are SP values (solubility parameters) of water and acetone described in the above document.
<img id="000005" he="13" wi="151" file="JP5241110B2_D0001.tif" img-format="tif" img-content="drawing" />
When measuring the hydrophilicity of a pigment in an ink, that is, a pigment dispersed by a resin (hereinafter referred to as a pigment dispersion), it can be calculated by the same method as described above. However, in the case of a pigment dispersion, it is necessary to measure in a state where the resin adsorbed on the pigment surface is desorbed.
Here, there are various means for desorbing the resin from the pigment, and specifically, the following method can be considered. Examples thereof include a method of salting out or coagulating an ink having a pigment dispersion. First, the organic group contained in the resin is analyzed by a conventional method. Then, for example, when the organic group contained in the resin contains an anionic group, an acid such as hydrochloric acid or sulfuric acid is added to the ink, and when the organic group contains a cationic group, an alkali such as sodium hydroxide is added. .. In this way, the pigment and resin in the ink can be precipitated by salting out. Alternatively, by adding an excessive amount of alcohol to the ink, the pigment and the resin in the ink can be precipitated by coagulation. Further, as a method of precipitating the pigment in the ink, the pigment can be effectively taken out by a combination of salting out or coagulation, centrifugation or the like.
The precipitate containing the pigment thus obtained is separated by filtration or the like, the solid content is thoroughly washed with pure water, and the solid containing the pigment is placed in an oven at a temperature of 60 ° C for about overnight. dry. Then, the obtained dry matter containing the pigment is washed with a good solvent of the resin adsorbed on the pigment (a water-soluble organic solvent in which the resin can be easily dissolved). The good solvent needs to be selected depending on the type of resin, and for example, tetrahydrofuran or chloroform can be used. Then, after repeating the washing operation of the dry solid containing the pigment with a good solvent about 3 times, a vacuum dryer is used to remove the remaining water and the water-soluble organic solvent, and the degree of vacuum is several hundred Pa or less. , Dry for about 3 hours under the condition of temperature 60 ° C. By such a method, only the pigment can be taken out from the ink.
<Water-based ink> The first ink of the present invention is characterized by first containing a pigment having a hydrophilicity δm in the range of 21.5 or more and 23.5 or less. Further, in the first method described above, it is necessary that the content (mass%) of the water-soluble organic solvent in the ink is 5.0% by mass or more and 17.5% by mass or less based on the total mass of the ink. Further, in the above-mentioned second method, CI pigment violet 23 is used as the pigment, and the second ink is made to have a specific absorption wavelength by a method such as adjusting the dispersion state of the pigment. It is necessary. As described above, CI Pigment Violet 23 has a pigment having a hydrophilicity of δm of 21.5 or more and 23.5 or less. The first and second inks of the present invention may have the same constitution as the conventional pigment ink except for the above. Each component constituting the ink of the present invention will be described below.
(Pigment) Specific commercially available pigments having a hydrophilicity δm in the range of 21.5 or more and 23.5 or less used in the present invention include the following. For example, Novoperm Yellow H2G (product name: Clariant), B8700 (product name: Ciba Specialty Chemicals), Hostaperm Violet RL SP (product name: Clariant), Monac 880 (product name: Cabot), etc. .. In terms of CI number, Novoperm Yellow H2G is CI Pigment Yellow 120. Further, Hostaperm Violet RL SP is CI Pigment Violet 23 which can be particularly preferably used for the first and second inks of the present invention. In the first ink of the present invention, as long as the hydrophilicity δm of the pigment is in the range of 21.5 or more and 23.5 or less, not only the pigments listed above but also any of the pigments listed below can be used. Good. Further, in the first and second inks of the present invention, in addition to the above-mentioned specific pigments, the pigments listed below can be used in combination.
[Carbon black] As the carbon black, any carbon black such as furnace black, lamp black, acetylene black, and channel black can be used. Specifically, commercially available products such as those listed below can be used.
Ray-Ban: 7000, 5750, 5250, 5000ULTRA, 3500, 2000, 1500, 1250, 1200, 1190ULTRA-II, 1170, 1255 (above, made in Colombia). Black Pearls L, Legal: 400R, 330R, 660R, Mougle L; Monac: 700, 800, 880, 900, 1000, 1100, 1300, 1400, 2000; Vulcan XC-72R (above, made by Cabot). Color Black: FW1, FW2, FW2V, FW18, FW200, S150, S160, S170; Printex: 35, U, V, 140U, 140V; Special Black: 6, 5, 4A, 4 (above, made by Degussa). No.25, No.33, No.40, No.47, No.52, No.900, No.2300, MCF-88, MA600, MA7, MA8, MA100 (all manufactured by Mitsubishi Chemical Corporation), etc.
It is also possible to use carbon black newly prepared for the present invention. Further, the pigment is not limited to carbon black, and magnetic fine particles such as magnetite and ferrite, titanium black, and the like may be used as the pigment.
[Organic pigment] In addition to carbon black, various organic pigments can be used. Specific examples of the organic pigment include the following. Water-insoluble azo pigments such as toluidine red, toluidine maroon, hanza yellow, benzidine yellow, and pyrazolone red. Water-soluble azo pigments such as Ritol Red, Helio Bordeaux, Pigment Scarlet, Permanent Red 2B. Derivatives from vat dyes such as alizarin, indigo maroon, and thioindigo maroon. Phthalocyanine pigments such as phthalocyanine blue and phthalocyanine green. Quinacridone pigments such as quinacridone red and quinacridone magenta. Perylene pigments such as perylene red and perylene scarlet. Isoindolinone pigments such as isoindolinone yellow and isoindolinone orange. Benz imidazolone-based pigments such as benz imidazolone yellow, benz imidazolone orange, and benz imidazolone red. Pyran Slon pigments such as Pyran Slon Red and Pyran Slon Orange. Indigo pigment. Condensed azo pigment. Thioingigo pigment. Diketopyrrolopyrrole pigment. Flavanthron yellow, acylamide yellow, quinophthalone yellow, nickel azo yellow, copper azomethin yellow, perinone orange, anthrone orange, dianthraquinonyl red, dioxazine violet, etc. Of course, the present invention is not limited to these.
In addition, the organic pigments that can be used in the present invention are represented by CI numbers, for example, the following. CI Pigment Yellow: 12, 13, 14, 17, 20, 24, 74, 83, 86, 93, 97, 109, 110, 117, 120, 125, 128, 137, 138, 147, 148, 150, 151, 153, 154, 166, 168, 180, 185 and so on. CI Pigment Orange: 16, 36, 43, 51, 55, 59, 61, 71 and more. CI Pigment Red: 9, 48, 49, 52, 53, 57, 97, 122, 123, 149, 168, 175, 176, 177 and more. Also, 180, 184, 192, 215, 216, 217, 220, 223, 224, 226, 227, 228, 238, 240, 254, 255, 272, etc. CI Pigment Violet: 19, 23, 29, 30, 37, 40, 50 and more. CI Pigment Blue: 15, 15: 1, 15: 3, 15: 4, 15: 6, 22, 60, 64 and more. CI Pigment Green: 7, 36 and so on. CI Pigment Brown: 23, 25, 26 and more.
In the present invention, the content (mass%) of the pigment in the ink is 0.1% by mass or more and 15.0% by mass or less, and further 1.0% by mass or more and 10.0% by mass or less, particularly 1.0% by mass, based on the total mass of the ink. It is preferably 3.0% by mass or less. If the content of the pigment is less than 0.1% by mass, a sufficient optical density may not be obtained, and if it exceeds 15.0% by mass, the sticking resistance may be lowered.
(Pigment dispersion method) As the pigment constituting the first and second inks of the present invention, a resin dispersion type pigment (resin dispersion type pigment) dispersed by using a polymer dispersant is used. As the dispersant used for the resin dispersion type pigment, it is preferable to use a dispersant capable of stably dispersing the pigment in an aqueous medium by the action of a hydrophilic group, particularly an anionic group. As the specific dispersant, for example, the following can be used. Styrene-acrylic acid copolymer, styrene-acrylic acid-acrylic acid alkyl ester copolymer, styrene-maleic acid copolymer, styrene-maleic acid-acrylic acid alkyl ester copolymer. Styrene-methacrylic acid copolymer, styrene-methacrylic acid-acrylic acid alkyl ester copolymer, styrene-maleic acid half ester copolymer. Vinyl naphthalene-acrylic acid copolymer, vinyl naphthalene-maleic acid copolymer, styrene-maleic anhydride-maleic acid half ester copolymer, benzyl methacrylate-methacrylic acid copolymer, etc. Or salts of these copolymers and the like.
Moreover, the form of the resin used as a dispersant is preferably a block polymer. The reason for this is as follows. In the block polymer, hydrophilic units and hydrophobic units are regularly arranged in the molecular structure. On the other hand, in the random polymer, hydrophobic units and hydrophilic units are irregularly arranged in the molecular structure. Therefore, in the block polymer, a hydrophobic unit that is easily adsorbed on the pigment is locally present in the structure of the resin as compared with the random polymer. Due to such a difference in the form of the resin, the block polymer is less likely to be desorbed from the pigment as compared with the random polymer, and the generation of deposits in the ink flow path and in the vicinity of the ejection port can be reduced more effectively. it can. Examples of the block polymer that can be used in the present invention include the following. An AB block type in which a hydrophobic monomer unit (called A block) and an ionic hydrophilic monomer unit (called B block) are localized can be mentioned. Alternatively, an ABC block type to which a nonionic hydrophilic monomer unit (called C block) is further added can be mentioned. Of course, the present invention is not limited to this.
The weight average molecular weight of the above-mentioned dispersant is preferably 1,000 or more and 30,000 or less. In the present invention, it is particularly preferable that the weight average molecular weight of the dispersant is 1,500 or more and 6,000 or less, and further preferably 2,000 or more and 5,000 or less. Here, it is extremely rare to use a resin having a weight average molecular weight of 2,000 or more and 5,000 or less as a dispersant in a normal pigment ink for an inkjet. However, in the present invention, it is particularly preferable to use a resin having such a small weight average molecular weight for the reasons described below. As described above, a pigment having a hydrophilicity δm in the range of 21.5 or more and 23.5 or less has a property that the resin adsorbed on the pigment is easily detached. At this time, even if the resin is desorbed from the pigment, since the resin having a small weight average molecular weight is used, the resin existing in the ink can be relatively easily re-adsorbed to the portion where the resin is desorbed from the pigment. it can. That is, since the weight average molecular weight of the dispersant is small, it is not easily affected by the steric hindrance of the resin that has already been adsorbed, and the above-mentioned resin is likely to be re-adsorbed. As a result, a stable dispersed state can be maintained, so that the generation of deposits in the ink flow path and in the vicinity of the ejection port can be further suppressed. However, if the weight average molecular weight of the dispersant is too small, the dispersed state of the pigment becomes unstable, and it may not be possible to suppress the generation of deposits in the ink flow path and in the vicinity of the ejection port. Therefore, in the present invention, it is most preferable to use a resin having a weight average molecular weight in the range of 2,000 or more and 5,000 or less as a dispersant.
Further, the content of the resin in the ink is preferably 30.0% or more and 90.0% or less based on the content of the pigment in the ink (resin content / pigment content). If the resin content in the ink is less than 30.0% based on the pigment content (ie, resin / pigment), it may be difficult to maintain the dispersion stability of the pigment over a long period of time. Further, even if the content of the resin in the ink is larger than 90.0% based on the content of the pigment, the effect on the dispersion stability and the generation of deposits may not be further improved. Rather, the viscosity of the ink increases, and when the ink is ejected from the recording head, the resin adheres to the face surface (the surface having the ejection port for ejecting the ink), which causes ejection defects. , Reliability may decrease.
The resin content (mass%) in the ink is preferably 0.5% by mass or more and 3.0% by mass or less, more preferably 0.9% by mass or more and 1.8% by mass or less, based on the total mass of the ink. When the content of the resin in the ink is 0.9% by mass or more and 1.8% by mass or less as described above, the ejection stability does not decrease and excellent dispersion stability can be obtained over a long period of time. Because.
(Aqueous medium) It is preferable to use water or an aqueous medium containing water and a water-soluble organic solvent as the ink. In the first ink of the present invention, the content (mass%) of the water-soluble organic solvent in the ink needs to be 5.0% by mass or more and 17.5% by mass or less based on the total mass of the ink. Further, in the second ink of the present invention, the content (mass%) of the water-soluble organic solvent in the ink is 3.0% by mass or more and 50.0% by mass or less, and further 4.0% by mass or more and 20.0% by mass or less, particularly 5.0. It is preferably mass% or more and 17.5 mass% or less.
As the water-soluble organic solvent, for example, the following can be used. Alkanol having 1 to 4 carbon atoms such as ethanol, isopropanol, n-butanol, isobutanol, second butanol, and third butanol. Carboxylic acid amides such as N, N-dimethylformamide or N, N-dimethylacetamide. Ketones or keto alcohols such as acetone, methyl ethyl ketone, 2-methyl-2-hydroxypentane-4-one. Cyclic ethers such as tetrahydrofuran and dioxane. Glycerin. Glycos such as ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2- or 1,3-propylene glycol, 1,2- or 1,4-butylene glycol, polyethylene glycol and thiodiglycol. Many such as 1,3-butanediol, 1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 2-methyl-1,3-propanediol, 1,2,6-hexanetriol, etc. Value alcohols. Alkyl ethers of polyhydric alcohols such as ethylene glycol monomethyl (or ethyl) ether, diethylene glycol monomethyl (or ethyl) ether, and triethylene glycol monoethyl (or butyl) ether. Heterocycles such as 2-pyrrolidone, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, and N-methylmorpholine. Sulfur-containing compounds such as dimethyl sulfoxide. These water-soluble organic solvents can be used alone or in combination of two or more.
In the present invention, among the above-mentioned water-soluble organic solvents, it is preferable to use glycerin, ethylene glycol, diethylene glycol, polyethylene glycol, and 2-pyrrolidone. When a resin having a weight average molecular weight of 1,500 or more and 6,000 or less, and further 2,000 or more and 5,000 or less is used as the pigment dispersant, it is particularly preferable to use polyethylene glycol having an average molecular weight of 1,000 or more as the water-soluble organic solvent. .. This is because an ink containing a resin having a weight average molecular weight as described above and polyethylene glycol having an average molecular weight of 1,000 or more has particularly good ejection stability when continuously ejected for a long period of time. The upper limit of the average molecular weight of polyethylene glycol is preferably 1,500 or less.
Further, it is preferable to use deionized water as the water. The water content (mass%) in the ink is preferably 50.0% by mass or more and 95.0% by mass or less, more preferably 78.5% by mass or more and 91.0% by mass or less, based on the total mass of the ink. Further, in the case of the first ink of the present invention, it is particularly preferable that the water content (mass%) in the ink is 78.5% by mass or more and 91.0% by mass or less. When the content of water is 78.5% by mass or more, the content of water in the ink becomes relatively large, while the content of components other than water such as water-soluble organic solvent and surfactant is relative. Becomes smaller. As a result, the above-mentioned components such as the water-soluble organic solvent and the surfactant suppress the action of weakening the adsorptive force between the pigment and the resin, and the generation of deposits can be suppressed more effectively.
(Other additives) The ink of the present invention may further contain various additives, if necessary, in addition to the components described above. For example, solid moisturizers such as urea and urea derivatives, trimethylolethane, and trimethylolpropane can be used. Further, a surfactant, an antifoaming agent, an antiseptic, an antifungal agent and the like can be used to obtain an ink having desired physical properties. However, in the case of an ink containing a surfactant having a high orientation rate to the pigment, the surfactant tends to be selectively oriented at a position where the resin is desorbed from the pigment. As a result, a stable dispersed state cannot be maintained, and the discharge stability may decrease. Therefore, in the present invention, in order to obtain discharge stability, when a surfactant is used, the critical micelle concentration of the aqueous solution containing only the surfactant is 28 dyn / cm (mN / m) or more. It is preferable to select and use. At this time, the content (mass%) of the surfactant in the ink is preferably 0.7% by mass or more and 1.0% by mass or less based on the total mass of the ink.
<Inkjet recording method> The first and second inks of the present invention are preferably used in an inkjet recording method in which ink is ejected by an inkjet recording method to record on a recording medium. Examples of the inkjet recording method include a method of ejecting ink by applying mechanical energy to the ink and a method of ejecting ink by applying thermal energy to the ink. The first and second inks of the present invention can obtain remarkable effects, especially when used in an inkjet recording method utilizing thermal energy.
<Ink cartridge> The ink cartridge of the present invention is characterized by comprising an ink accommodating portion accommodating the first or second ink of the present invention.
<Recording unit> The recording unit of the present invention is characterized by including an ink accommodating portion for accommodating the first or second ink of the present invention and a recording head for ejecting these inks. In particular, when the recording head is a recording unit that ejects ink by applying thermal energy to the ink, a remarkable effect can be obtained.
<Inkjet recording device> The inkjet recording apparatus of the present invention is characterized by including an ink accommodating portion for accommodating the first or second ink of the present invention and a recording head for ejecting ink. In particular, when the recording head is an inkjet recording device of a type that ejects ink by applying thermal energy to the ink, a remarkable effect can be obtained.
The schematic configuration of the mechanical part of the inkjet recording device will be described below. From the role of each mechanism, the inkjet recording device is composed of a paper feed unit, a transport unit, a carriage unit, a paper discharge unit, a cleaning unit, and an exterior unit that protects these and gives them a design. The outline of these will be described below.
FIG. 2 is a perspective view of an inkjet recording device. 3 and 4 are views for explaining the internal mechanism of the inkjet recording device, FIG. 3 is a perspective view from the upper right part, and FIG. 4 is a side sectional view of the inkjet recording device. is there.
When feeding paper, first, in the paper feed section including the paper feed tray M2060, a predetermined number of recording media are sent to the nip section composed of the paper feed roller M2080 and the separation roller M2041 (FIGS. 3 and 4). reference). The recording medium is separated at the nip portion, and only the highest-level recording medium is conveyed. The recording medium sent to the transport unit is guided by the pinch roller holder M3000 and the paper guide flapper M3030, and is fed to the roller pair of the transport roller M3060 and the pinch roller M3070. The roller pair consisting of the transfer roller M3060 and the pinch roller M3070 is rotated by the drive of the LF motor E0002, and the recording medium is conveyed on the platen M3040 by this rotation (see FIGS. 3 and 4 above).
When forming an image, the carriage section arranges the recording head H1001 (see FIG. 5) at the target image forming position, and ink is ejected to the recording medium according to a signal from the electric board E0014 (see FIG. 3). To. The detailed configuration of the recording head H1001 will be described later. The main scan, in which the carriage M4000 (see FIG. 3) scans in the column direction while recording by the recording head H1001, and the sub-scan, in which the transfer roller M3060 (see FIGS. 3 and 4) conveys the recording medium in the row direction, alternate. By repeating the above steps, an image is formed on the recording medium.
Finally, the recording medium is sandwiched between the nips of the first paper ejection roller M3110 and the spur M3120 at the paper ejection section (see FIG. 4), is conveyed, and is ejected to the paper ejection tray M3160 (see FIG. 2).
The cleaning unit cleans the recording head H1001. When the pump M5000 (see FIG. 3) is operated with the cap M5010 (see FIG. 3) in close contact with the discharge port of the recording head H1001, the cleaning unit sucks ink or the like from the recording head H1001. In addition, if the ink remaining on the cap M5010 is sucked with the cap M5010 open, the ink does not stick or other harmful effects occur.
(Recording head configuration) The configuration of the head cartridge H1000 will be described (see FIG. 5). The head cartridge H1000 includes a recording head H1001, a means for mounting the ink cartridge H1900, and a means for supplying ink from the ink cartridge H1900 to the recording head. The head cartridge H1000 is detachably mounted on the carriage M4000 (see FIG. 3).
FIG. 5 is a diagram showing how the ink cartridge H1900 is attached to the head cartridge H1000. Inkjet recorders form images with, for example, yellow, magenta, cyan, black, red, green, and blue inks. Therefore, the ink cartridge H1900 is also prepared independently for 7 colors. In the above, the ink of the present invention is used as at least one kind of ink. Then, as shown in FIG. 5, each ink cartridge is removable from the head cartridge H1000. The ink cartridge H1900 can be attached / detached with the head cartridge H1000 mounted on the carriage M4000 (see FIG. 3).
FIG. 6 is an exploded perspective view of the head cartridge H1000. The head cartridge H1000 is composed of a recording element substrate, a plate, an electrical wiring substrate H1300, a tank holder H1500, a flow path forming member H1600, a filter H1700, a seal rubber H1800, and the like. The recording element substrate is composed of a first recording element substrate H1100 and a second recording element substrate H1101, and the plate is composed of a first plate H1200 and a second plate H1400.
The first recording element substrate H1100 and the second recording element substrate H1101 are Si substrates, and a plurality of recording elements (nozzles) for ejecting ink on one side thereof are formed by photolithography technology. The electrical wiring such as Al that supplies electric power to each recording element is formed by a film forming technique, and a plurality of ink flow paths corresponding to the individual recording elements are also formed by a photolithography technique. Further, an ink supply port for supplying ink to a plurality of ink flow paths is formed so as to open on the back surface.
FIG. 7 is an enlarged front view illustrating the configurations of the first recording element substrate H1100 and the second recording element substrate H1101. H2000 to H2600 are rows of recording elements (hereinafter, also referred to as nozzle rows) that supply different inks. The first recording element substrate H1100 is formed with nozzle rows for three colors: a yellow ink nozzle row H2000, a magenta ink nozzle row H2100, and a cyan ink nozzle row H2200. On the second recording element substrate H1101, nozzle rows for four colors of red ink nozzle row H2300, black ink nozzle row H2400, green ink nozzle row H2500, and blue ink nozzle row H2600 are formed. There is.
Each nozzle row is composed of 768 nozzles arranged at intervals of 1,200 dpi (dot / inch; reference value) in the transport direction of the recording medium, and ejects about 2 picolitres of ink. The opening area at each discharge port is approximately 100 μm.<sup>2</sup>Is set to.
Hereinafter, description will be made with reference to FIGS. 5 and 6. The first recording element substrate H1100 and the second recording element substrate H1101 described above are adhesively fixed to the first plate H1200. An ink supply port H1201 for supplying ink to the first recording element substrate H1100 and the second recording element substrate H1101 is formed here. Further, a second plate H1400 having an opening is adhesively fixed to the first plate H1200. The second plate H1400 holds the electric wiring board H1300 so that the electric wiring board H1300, the first recording element board H1100, and the second recording element board H1101 are electrically connected.
The electric wiring board H1300 applies an electric signal for ejecting ink from each nozzle formed on the first recording element board H1100 and the second recording element board H1101. The electric wiring board H1300 is located at the end of the electric wiring and the electric wiring corresponding to the first recording element board H1100 and the second recording element board H1101, and is located at the end of the electric wiring and is external for receiving an electric signal from the inkjet recording device. It has a signal input terminal H1301. The external signal input terminal H1301 is positioned and fixed on the back side of the tank holder H1500.
A flow path forming member H1600 is fixed to the tank holder H1500 holding the ink cartridge H1900 by, for example, ultrasonic welding to form an ink flow path H1501 leading from the ink cartridge H1900 to the first plate H1200. A filter H1700 is provided at the end of the ink flow path H1501 that engages with the ink cartridge H1900 on the ink cartridge side so as to prevent dust from entering from the outside. Further, a seal rubber H1800 is attached to the engaging portion with the ink cartridge H1900 to prevent the ink from evaporating from the engaging portion.
Further, as described above, the head cartridge H1000 is configured by connecting the tank holder portion and the recording head portion H1001 by adhesion or the like. The tank holder portion is composed of a tank holder H1500, a flow path forming member H1600, a filter H1700, and a seal rubber H1800. The recording head unit H1001 is composed of a first recording element substrate H1100, a second recording element substrate H1101, a first plate H1200, an electrical wiring board H1300, and a second plate H1400.
Here, as one form of a recording head, a thermal inkjet recording head that records using an electrothermal converter (recording element) that generates thermal energy for causing film boiling in the ink in response to an electric signal. Said. As for this typical structure and principle, for example, it is preferable to use the basic principle disclosed in US Pat. Nos. 4,723,129 and 4,740,796. This method can be applied to both so-called on-demand type and continuous type.
It is particularly effective to apply the thermal inkjet method to the on-demand type. In the case of the on-demand type, at least one drive that corresponds to the recorded information and gives a rapid temperature rise exceeding the nucleate boiling to the electric heat converter arranged corresponding to the liquid flow path that holds the ink. Apply a signal. As a result, thermal energy can be generated in the electrothermal converter, the ink can be boiled, and as a result, bubbles in the ink corresponding to this drive signal can be formed on a one-to-one basis. At least one drop is formed by ejecting ink through the ejection port by the growth and contraction of the bubbles. When the drive signal has a pulse shape, the growth and contraction of bubbles are immediately and appropriately performed, so that ink ejection having particularly excellent responsiveness can be achieved, which is more preferable.
Further, the ink of the present invention can be preferably used not only in the above-mentioned thermal inkjet method but also in an inkjet recording device using mechanical energy as described below. An inkjet recording device of this form includes a nozzle-forming substrate having a plurality of nozzles, a pressure generating element made of a piezoelectric material and a conductive material arranged to face the nozzles, and ink that fills the periphery of the pressure generating element. Become. Then, the pressure generating element is displaced by the applied voltage, and the ink is ejected from the nozzle.
As described above, the inkjet recording device is not limited to the one in which the recording head and the ink cartridge are separated, and the one in which they are inseparably integrated may be used. Further, the ink cartridge is separably or inseparably integrated with the recording head and mounted on the carriage, or is provided at a fixed portion of the inkjet recording device and records via an ink supply member such as a tube. It may supply ink to the head. Further, when the ink cartridge is provided with a configuration for applying a preferable negative pressure to the recording head, the following configuration can be used. That is, a form in which an absorber is arranged in an ink accommodating portion of an ink cartridge, or a form in which a flexible ink accommodating bag and a spring portion acting with an urging force in a direction for expanding the internal volume thereof are provided. Can be. Further, the inkjet recording apparatus may take the form of a line printer in which recording elements are arranged over a range corresponding to the entire width of the recording medium, in addition to adopting the serial type recording method as described above.
Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. The present invention is not limited thereto as long as the gist thereof is not exceeded. In the following description, "part" and "%" are based on mass unless otherwise specified.
<Preparation of pigment dispersion> Each pigment dispersion was prepared by the following procedure and composition. Table 1 shows the acid value and weight average molecular weight of the resin used to prepare each pigment dispersion, the type of resin (block polymer or random polymer), and the dispersion conditions (dispersion time and peripheral speed) when preparing the pigment dispersion. , And the content [%] of the pigment and the resin in each pigment dispersion.
The pigments used to prepare the pigment dispersions 1 to 18 are all CI Pigment Violet 23 (product name: Hostaperm Violet RL SP; manufactured by Clariant). The hydrophilicity δm of this pigment was measured as follows. First, 0.1 g of the above pigment was added to a beaker containing a stirrer and 50 ml of ion-exchanged water, and the mixture was gently stirred to the extent that no vortex was formed. Acetone was added dropwise thereto using a burette under stirring. The amount of acetone dropped A required for the floating pigment to get wet and settle was 6.3 [mL]. Then, when the hydrophilicity δm of the pigment was calculated from the following formula (3), it was 21.9. 23.43 and 9.75 in the following formula (3) are SP values (solubility parameters) of water and acetone.<img id="000006" he="13" wi="151" file="JP5241110B2_D0001.tif" img-format="tif" img-content="drawing" />
(Preparation of pigment dispersion 1) Pigment solution 1 was prepared by mixing 10 parts of the pigment, 9 parts of the dispersant, and 81 parts of ion-exchanged water. The dispersant is a resin A obtained by neutralizing an AB type block polymer having an acid value of 250 and a weight average molecular weight of 6,000, which is synthesized by a conventional method using benzyl methacrylate and methacrylic acid as raw materials, with an aqueous solution of potassium hydroxide. Was used. This pigment solution 1 was charged into a circulating bead mill, and 85 parts of 0.3 mm zirconia beads were filled and dispersed. At this time, the pigment dispersion 1 was prepared with the dispersion time and peripheral speed as the values shown in Table 1, respectively. Then, the coarse particles were removed by centrifugation. Furthermore, by pressurizing and filtering with a microfilter (manufactured by Fujifilm) with a pore size of 3.0 μm, the pigment dispersion 1 having a pigment content (solid content) of 10% by mass and a resin A content of 9% by mass can be obtained. Prepared.
(Preparation of pigment dispersion 2) Similar to Pigment Dispersion 1, the pigment content (solid content) was 10% by mass and the resin A content was 9% by mass, except that the dispersion time and peripheral speed were set to the values shown in Table 1, respectively. Pigment dispersion 2 was prepared.
(Preparation of Pigment Dispersion 3) Similar to Pigment Dispersion 1, the pigment content (solid content) was 10% by mass and the resin A content was 9% by mass, except that the dispersion time and peripheral speed were set to the values shown in Table 1, respectively. Pigment dispersion 3 was prepared.
(Preparation of pigment dispersion 4) Similar to Pigment Dispersion 1, the pigment content (solid content) was 10% by mass and the resin A content was 9% by mass, except that the dispersion time and peripheral speed were set to the values shown in Table 1, respectively. Pigment dispersion 4 was prepared.
(Preparation of Pigment Dispersion 5) Pigment solution 2 was prepared by mixing 10 parts of the pigment, 9 parts of the dispersant, and 81 parts of ion-exchanged water. The dispersant is a resin B obtained by neutralizing an AB type block polymer having an acid value of 250 and a weight average molecular weight of 1,500, which is synthesized by a conventional method using benzyl methacrylate and methacrylic acid as raw materials, with an aqueous solution of potassium hydroxide. Was used. Similar to Pigment Dispersion 1, the pigment content (solid content) is 10 mass, except that Pigment Solution 2 is used instead of Pigment Solution 1 and the dispersion time and peripheral speed are set to the values shown in Table 1, respectively. A pigment dispersion 5 having a% resin B content of 9% by mass was prepared.
(Preparation of pigment dispersion 6) Pigment solution 3 was prepared by mixing 10 parts of the pigment, 9 parts of the dispersant, and 81 parts of ion-exchanged water. The dispersant is a resin C obtained by neutralizing an AB type block polymer having an acid value of 250 and a weight average molecular weight of 2,000, which is synthesized by a conventional method using benzyl methacrylate and methacrylic acid as raw materials, with an aqueous solution of potassium hydroxide. Was used. Similar to Pigment Dispersion 1, the pigment content (solid content) is 10 mass, except that Pigment Solution 3 is used instead of Pigment Solution 1 and the dispersion time and peripheral speed are set to the values shown in Table 1, respectively. A pigment dispersion 6 having a% resin C content of 9% by mass was prepared.
(Preparation of pigment dispersion 7) Pigment solution 4 was prepared by mixing 10 parts of the pigment, 9 parts of the dispersant, and 81 parts of ion-exchanged water. The dispersant is a resin D obtained by neutralizing an AB type block polymer having an acid value of 250 and a weight average molecular weight of 5,000, which is synthesized by a conventional method using benzyl methacrylate and methacrylic acid as raw materials, with an aqueous solution of potassium hydroxide. Was used. Similar to Pigment Dispersion 1, the pigment content (solid content) is 10 mass, except that Pigment Solution 4 is used instead of Pigment Solution 1 and the dispersion time and peripheral speed are set to the values shown in Table 1, respectively. A pigment dispersion 7 having a% resin D content of 9% by mass was prepared.
(Preparation of Pigment Dispersion 8) Similar to Pigment Dispersion 1, the pigment content (solid content) was 10% by mass and the resin A content was 9% by mass, except that the dispersion time and peripheral speed were set to the values shown in Table 1, respectively. Pigment dispersion 8 was prepared.
(Preparation of pigment dispersion 9) Similar to Pigment Dispersion 1, the pigment content (solid content) was 10% by mass and the resin A content was 9% by mass, except that the dispersion time and peripheral speed were set to the values shown in Table 1, respectively. Pigment dispersion 9 was prepared.
(Preparation of pigment dispersion 10) Similar to Pigment Dispersion 1, the pigment content (solid content) was 10% by mass and the resin A content was 9% by mass, except that the dispersion time and peripheral speed were set to the values shown in Table 1, respectively. Pigment dispersion 10 was prepared.
(Preparation of pigment dispersion 11) Similar to Pigment Dispersion 1, the pigment content (solid content) was 10% by mass and the resin A content was 9% by mass, except that the dispersion time and peripheral speed were set to the values shown in Table 1, respectively. Pigment dispersion 11 was prepared.
(Preparation of pigment dispersion 12) The pigment content (solid content) is the same as that of the pigment dispersion 1 except that the pigment solution 4 is used instead of the pigment solution 1 and the dispersion time and peripheral speed are set to the values shown in Table 1, respectively. A pigment dispersion 12 having 10% by mass and a resin D content of 9% by mass was prepared.
(Preparation of pigment dispersion 13) The pigment solution 5 was prepared by mixing 10 parts of the pigment, 9 parts of the dispersant, and 81 parts of ion-exchanged water. The dispersant is a resin E obtained by neutralizing an AB type block polymer having an acid value of 250 and a weight average molecular weight of 2,000, which is synthesized by a conventional method using benzyl methacrylate and methacrylic acid as raw materials, with an aqueous solution of potassium hydroxide. Was used. Similar to Pigment Dispersion 1, the pigment content (solid content) is 10 mass, except that Pigment Solution 5 is used instead of Pigment Solution 1 and the dispersion time and peripheral speed are set to the values shown in Table 1, respectively. A pigment dispersion 13 having a% resin E content of 9% by mass was prepared.
(Preparation of pigment dispersion 14) Pigment solution 6 was prepared by mixing 10 parts of the pigment, 9 parts of the dispersant, and 81 parts of ion-exchanged water. The dispersant is a resin F obtained by neutralizing an AB type block polymer having an acid value of 250 and a weight average molecular weight of 1,500, which is synthesized by a conventional method using benzyl methacrylate and methacrylic acid as raw materials, with an aqueous solution of potassium hydroxide. Was used. Similar to Pigment Dispersion 1, the pigment content (solid content) is 10 mass, except that Pigment Solution 6 is used instead of Pigment Solution 1 and the dispersion time and peripheral speed are set to the values shown in Table 1, respectively. A pigment dispersion 14 having a% resin F content of 9% by mass was prepared.
(Preparation of pigment dispersion 15) Pigment solution 7 was prepared by mixing 10 parts of the pigment, 2 parts of the dispersant, and 88 parts of ion-exchanged water. The resin A was used as the dispersant. Similar to Pigment Dispersion 1, the pigment content (solid content) is 10 mass, except that Pigment Solution 7 is used instead of Pigment Solution 1 and the dispersion time and peripheral speed are set to the values shown in Table 1, respectively. A pigment dispersion 15 having a% resin A content of 2% by mass was prepared.
(Preparation of pigment dispersion 16) Pigment solution 8 was prepared by mixing 10 parts of the pigment, 2 parts of the dispersant, and 88 parts of ion-exchanged water. The resin D was used as the dispersant. Similar to Pigment Dispersion 1, the pigment content (solid content) is 10 mass, except that Pigment Solution 8 is used instead of Pigment Solution 1 and the dispersion time and peripheral speed are set to the values shown in Table 1, respectively. A pigment dispersion 16 having a% resin D content of 2% by mass was prepared.
(Preparation of pigment dispersion 17) The pigment solution 9 was prepared by mixing 10 parts of the pigment, 9 parts of the dispersant, and 81 parts of ion-exchanged water. As the dispersant, resin G obtained by neutralizing a random polymer having an acid value of 250 and a weight average molecular weight of 6,000, which was synthesized by a conventional method using benzyl methacrylate and methacrylic acid as raw materials, with an aqueous solution of potassium hydroxide was used. There was. Similar to Pigment Dispersion 1, the pigment content (solid content) is 10 mass, except that Pigment Solution 9 is used instead of Pigment Solution 1 and the dispersion time and peripheral speed are set to the values shown in Table 1, respectively. A pigment dispersion 17 having a% resin G content of 9% by mass was prepared.
(Preparation of pigment dispersion 18) The pigment solution 10 was prepared by mixing 10 parts of the pigment, 9 parts of the dispersant, and 81 parts of ion-exchanged water. As the dispersant, resin H obtained by neutralizing a random polymer having an acid value of 250 and a weight average molecular weight of 5,000, which was synthesized by a conventional method using benzyl methacrylate and methacrylic acid as raw materials, with an aqueous solution of potassium hydroxide was used. There was. Similar to Pigment Dispersion 1, the pigment content (solid content) is 10 mass, except that Pigment Solution 10 is used instead of Pigment Solution 1 and the dispersion time and peripheral speed are set to the values shown in Table 1, respectively. A pigment dispersion 18 having a% resin H content of 9% by mass was prepared.
<img id="000007" he="176" wi="151" file="JP5241110B2_D0001.tif" img-format="tif" img-content="drawing" />
<First method> (Preparation of the first ink according to the first method) Each component shown in the upper part of Tables 2 and 3 below was mixed, sufficiently stirred, and then pressure-filtered with a microfilter (manufactured by Fujifilm) having a pore size of 1.0 μm to prepare inks 1 to 18. In addition, in Tables 2 and 3, in order to clarify the composition of each ink, the content of each of the pigment, the resin, the water, and the water-soluble organic solvent in the ink, and the content of the resin / The value of the pigment content and the value of the water-soluble organic solvent content / pigment content are also shown. Here, the content of the water-soluble organic solvent does not include the content of the surfactant.
<img id="000008" he="216" wi="151" file="JP5241110B2_D0001.tif" img-format="tif" img-content="drawing" />
<img id="000009" he="216" wi="151" file="JP5241110B2_D0001.tif" img-format="tif" img-content="drawing" />
(Evaluation of ink applied to the first method) (1) Continuous discharge stability Each of the inks obtained above was filled in an ink cartridge and mounted on an inkjet recording device PIXUS 990i (manufactured by Canon) that ejects ink by the action of heat energy. After that, 400 solid images of 19 cm x 26 cm were recorded on an A4 size PPC paper office planner (manufactured by Canon). At this time, after recording the 200th and 400th sheets, the nozzle check pattern of the PIXUS 990i was recorded. The obtained nozzle check pattern was visually observed to evaluate the continuous discharge stability. The evaluation criteria for continuous discharge stability are as follows. The evaluation results are shown in Table 4.
A: The nozzle check pattern is not disturbed and can be recorded normally. B: There is some disturbance in the nozzle check pattern, but there is no non-ejection. C: Nozzle check pattern clearly shows non-ejection and turbulence, and cannot be recorded normally.
(2) Sediments Each of the inks obtained above was filled in an ink cartridge and mounted on an inkjet recording device PIXUS 990i (manufactured by Canon) that ejects ink by the action of heat energy. After that, 400 solid images of 19 cm x 26 cm were recorded on an A4 size PPC paper office planner (manufactured by Canon). At this time, after recording the 200th and 400th sheets, the recording head was removed from the inkjet recording device, and the inside of the nozzle was observed with an optical microscope to check for the presence of deposits. Furthermore, 50 arbitrary nozzles are selected before recording and after recording the 200th and 400th sheets, and 40,000 ink droplets are ejected from each nozzle, and the mass per ink droplet before and after this ejection is as follows. I asked for it. First, the mass change of the ink cartridge before and after the ejection of 40,000 shots was measured, and the mass per ink droplet was measured from the total number of ejected ink droplets. Then, the rate of change in mass per drop of ink was determined before recording and on the 200th and 400th sheets, respectively, and evaluated using this. The evaluation criteria for sediments are as follows. The evaluation results are shown in Table 4.
A: There is almost no deposit. B: It was confirmed that a small amount of deposits were present on the nozzle wall, but the rate of change in mass per drop of ink was before recording and at the time of recording the 200th sheet, or before recording and at the time of recording the 400th sheet. By comparison, it was less than 5.0%. C: It was confirmed that the deposits were present in the nozzle as a whole, and the rate of change in mass per drop of ink was recorded before and at the 200th sheet, or before recording and at the 400th sheet. Compared with the time, it was 5.0% or more.
(3) Sticking recovery Each of the inks obtained above was filled in an ink cartridge and mounted on an inkjet recording device PIXUS 990i (manufactured by Canon) that ejects ink by the action of heat energy. After that, 400 solid images of 19 cm x 26 cm were recorded on an A4 size PPC paper office planner (manufactured by Canon). After that, the ink cartridge was left in an environment of room temperature of 35 ° C. and humidity of 10% for 2 weeks with the ink cartridge attached to the inkjet recording device. Then, after performing the recovery operation as appropriate, the nozzle check pattern of the PIXUS 990i was recorded. The sticking recovery property was evaluated by visually observing the obtained nozzle check pattern and confirming the recording state with the ink ejected from each nozzle. The evaluation criteria for sticking recovery are as follows. The evaluation results are shown in Table 4.
A: By performing manual suction within 2 times, all nozzles can be recovered without any problem. B: All nozzles were ejected by performing manual suction three times or more, but the nozzle check pattern was slightly disturbed in some nozzles. C: There are some nozzles that do not eject even if manual suction is performed 5 times or more.
<img id="000010" he="176" wi="151" file="JP5241110B2_D0001.tif" img-format="tif" img-content="drawing" />
As can be seen from Table 4, the evaluation results of the sediments of Example 3 and Reference Example 4 were the same. However, when the amount of sediment generated after recording 400 solid images of 19 cm × 26 cm was compared, the amount of sediment generated in Reference Example 4 was small. On the other hand, Example 3 was superior in sticking recovery to Reference Example 4. In addition, the amount of sediment generated after recording 400 sheets in Reference Examples 10 and 11 was slightly larger than that in other Examples. Moreover, the evaluation result of the continuous discharge stability of Reference Examples 9 and 10 was the same as the evaluation result of the continuous discharge stability in the examples other than Examples 3 and 6 and Reference Example 15. However, since the condition of the face surface after the test was relatively wet, the degree of twisting of the nozzle check pattern was slightly inferior. Further, the inks of Reference Examples 11 and 12 (inks 11 and 12) were placed in a Teflon (registered trademark) container, sealed tightly, and stored in an oven maintained at a temperature of 60 ° C. for 1 month. The particle size before and after storage was measured using a particle size measuring device ELS8000 (manufactured by Otsuka Electronics Co., Ltd.), and the rate of change in the particle size of each ink was measured. As a result, the rate of change in the particle size of Reference Example 12 was smaller than that of the rate of change in the particle size of Reference Example 11. As can be seen from Table 4, the evaluation results of sediment and adhesion recovery are shown in Examples 3 and 6,<u style="single">Reference example</u>In the case of 16, it was particularly excellent, and even in the 400th sheet, there was almost no deposit, and the adhesion recovery was also excellent.
<Second method> (Preparation of the second ink according to the second method) Each component shown in the upper part of Tables 5 and 6 below was mixed, sufficiently stirred, and then pressure-filtered with a microfilter (manufactured by Fujifilm) having a pore size of 1.0 μm to prepare inks 19 to 38. In addition, in Tables 5 and 6, in order to clarify the composition of each ink, the content of each of the pigment, the resin, the water, and the water-soluble organic solvent in the ink, and the content of the resin / The values of the pigment content are also shown. Here, the content of the water-soluble organic solvent does not include the content of the surfactant.
<img id="000011" he="208" wi="151" file="JP5241110B2_D0001.tif" img-format="tif" img-content="drawing" />
<img id="000012" he="208" wi="151" file="JP5241110B2_D0001.tif" img-format="tif" img-content="drawing" />
(Measurement of absorbance) Dilute each ink obtained above with ion-exchanged water 1,500 times (mass times), and use a spectrophotometer (trade name: U-3300, manufactured by Hitachi, Ltd.) to dilute the diluted ink to 400 nm or more. The absorbance was measured in the range of 700 nm or less. The measurement results are shown in Table 7. As can be seen from Table 7, the inks 19 to 34 are the inks of the examples that satisfy the requirements specified by the second method of the present invention. Inks 35 to 38 are comparative inks.
<img id="000013" he="216" wi="151" file="JP5241110B2_D0001.tif" img-format="tif" img-content="drawing" />
(Evaluation of the second ink according to the second method) For each of the inks obtained above, continuous ejection stability, deposits, and sticking recovery were evaluated in the same manner as described above. The evaluation results are shown in Table 8.
<img id="000014" he="184" wi="151" file="JP5241110B2_D0001.tif" img-format="tif" img-content="drawing" />
As you can see from Table 8,<u style="single">reference</u>Example 22<u style="single">, 23, Examples</u>24 and<u style="single">Reference example</u>2<u style="single">8~31</u>It was very good with almost no deposits. In particular, in Example 24 (ink 26), the rate of change in mass per drop of ink was 1% or less before and after recording 400 solid images of 19 cm × 26 cm. is this,<u style="single">reference</u>Approximately 2.7% in Example 22 (Ink 24),<u style="single">reference</u>It can be said that it was better than about 2.2% in Examples 23 and 29 (inks 25 and 31). Also,<u style="single">reference</u>The evaluation results of the sediments after recording 400 sheets in Examples 17 to 21 and after recording 200 sheets in Comparative Examples 3 and 5 were B. However, compared with the amount of sediment generated after recording 200 sheets in Comparative Examples 3 and 5,<u style="single">reference</u>The amount of sediment generated after recording 400 sheets in Examples 17 to 21 was clearly small. In addition, it should be noted.<u style="single">reference</u>The evaluation result of the continuous discharge stability of Example 29 was A, and there was almost no decrease in the discharge stability due to the sediment. However, as compared to other embodiments where the continuous discharge stability is A,<u style="single">reference</u>Since the condition of the face surface after the test of Example 29 was relatively wet, the degree of twist of the nozzle check pattern was slightly inferior. further,<u style="single">reference</u>The inks of Examples 27 and 28 (inks 29 and 30) were placed in Teflon (registered trademark) containers, sealed, and stored in an oven maintained at a temperature of 60 ° C for 1 month. The particle size before and after storage was measured using a particle size measuring device ELS8000 (manufactured by Otsuka Electronics Co., Ltd.), and the rate of change in the particle size of each ink was measured. as a result,<u style="single">reference</u>Compared to the rate of change in particle size in Example 27,<u style="single">reference</u>The rate of change in particle size in Example 28 was smaller. Furthermore,<u style="single">reference</u>The inks of Examples 30 and 31 (inks 32 and 33) were placed in Teflon (registered trademark) containers, sealed, and stored in an oven maintained at a temperature of 60 ° C. for 1 month. The particle size before and after storage was measured using a particle size measuring device ELS8000 (manufactured by Otsuka Electronics Co., Ltd.), and the rate of change in the particle size of each ink was measured. as a result,<u style="single">reference</u>Compared with the rate of change in particle size in Example 30,<u style="single">reference</u>The rate of change in particle size in Example 31 was smaller.
<figref num="1">It is a schematic diagram which shows the mechanism of sediment generation.</figref><figref num="2">It is a perspective view of the inkjet recording apparatus.</figref><figref num="3">It is a perspective view of the mechanism part of the inkjet recording apparatus.</figref><figref num="4">It is sectional drawing of the inkjet recording apparatus.</figref><figref num="5">It is a perspective view which shows the state which the ink cartridge is attached to the head cartridge.</figref><figref num="6">It is an exploded perspective view of a head cartridge.</figref><figref num="7">It is a front view which shows the recording element substrate in a head cartridge.</figref><figref num="8">It is a graph which shows an example of the absorption spectrum of CI pigment violet 23.</figref>
Code description
1: Heater 2: Ink flow path 3: Discharge port 4: Aggregates 5: Ink drops 6: Bubbles M2041: Separation roller M2060: Paper tray M2080: Paper feed roller M3000: Pinch roller holder M3030: Paper guide flapper M3040: Platen M3060: Conveying roller M3070: Pinch roller M3110: Paper ejection roller M3120: Spur M3160: Output tray M4000: Carriage M5000: Pump M5010: Cap E0002: LF motor E0014: Electrical board H1000: Head cartridge H1001: Recording head H1100: First recording element substrate H1101: Second recording element substrate H1200: First plate H1201: Ink supply port H1300: Electrical wiring board H1301: External signal input terminal H1400: Second plate H1500: Tank holder H1501: Ink flow path H1600: Flow path forming member H1700: Filter H1800: Seal rubber H1900: Ink cartridge H2000: Yellow nozzle row H2100: Magenta nozzle row H2200: Cyan nozzle row H2300: Red nozzle row H2400: Black nozzle row H2500: Green nozzle row H2600: Blue nozzle row
23 sheets
Sheet 1 Sheet 2 Sheet 3 Sheet 4 Sheet 5 Sheet 6 Sheet 7 Sheet 8 Sheet 9 Sheet 10 Sheet 11 Sheet 12 Sheet 13 Sheet 14 Sheet 15 Sheet 16 Sheet 17 Sheet 18 Sheet 19 Sheet 20 Sheet 21 Sheet 22 Sheet 23
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| Document | Relation | Office |
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| JP2006027194A | Cites | Japan |
| JP2006008898A | Cites | Japan |
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| JP2007146152A | Cites | Japan |
| JP05112732A | Cites | Japan |
| JP09165528A | Cites | Japan |
| JP2003160751A | Cites | Japan |
| JP2005097557A | Cites | Japan |
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| 2007034015 | Japan | A | |
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| EP1820828A3 | European Patent Office (EPO) | A3 | |
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Numbers
- Publication
- 5241110
- Publication, DOCDB
- 5241110
- Publication, EPODOC
- JP5241110B
- Application
- 34015
- Application, DOCDB
- 2007034015
- Application, EPODOC
- JP20070034015
Titles2
- Japanese
- 水性インク、インクジェット記録方法、インクカートリッジ、記録ユニット、及びインクジェット記録装置
- English
- Water-based ink, inkjet recording method, ink cartridge, recording unit, and inkjet recording device
Classification
- IPC, 6
- B41J2 01
- B41M5 00
- C09D11 00
- C09D11 322
- C09D11 326
- C09D11 38
