Inkjet recording method and inkjet recording apparatus

Abstract

To provide an inkjet recording method that can suppress deflection of discharging of ink from occurring even when using a recording head having a protective tape attached to a discharge port surface that is a water-repellent surface, and prevent the deflection of discharging of ink even when using the recording head for a long time.SOLUTION: An inkjet recording method records an image using an inkjet recording device equipped with means for wiping a discharge port surface 30 subjected to water-repellent processing. A protective tape that is peeled off when used is attached to the discharge port surface 30 of a recording head 12. The method has a first cleaning sequence including a first wiping step and a second wiping step in which the discharge port surface 30 is wiped using one wiper 20 in a blade shape, where in the first wiping step, the discharge port surface 30 is wiped with a middle part 25 of the wiper 20 and in the second wiping step, the discharge port surface 30 is wiped with an edge part of the wiper 20.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to an inkjet recording method and an inkjet recording apparatus.

Background Art

[0002] According to the inkjet recording method, an image can be recorded on various recording media. In recent years, for the purpose of simplifying and miniaturizing the device configuration and shortening the preparation time until recording at the initial use, an inkjet recording apparatus equipped with an ink cartridge having a configuration in which a recording head is incorporated in an ink storage unit containing aqueous ink has become widespread. Since this ink cartridge is transported and stored in a state where the ejection port is filled with aqueous ink up to the opening tip, the ink is likely to evaporate. In order to suppress such evaporation of the ink, usually, a protective tape having an adhesive layer formed of an adhesive is attached to the ejection port surface, and the ink cartridge in which the recording head is incorporated with the ejection port closed is stored.

[0003] Also, in the business field, the inkjet recording method is also used when recording a full-color text including charts and the like on a recording medium such as plain paper. For such applications, the need for an ink containing a resin is increasing more and more so that the image quality is not easily deteriorated due to ink bleeding and an image excellent in water resistance and abrasion resistance can be recorded.

[0004] Inkjet recording is a method of recording images by ejecting liquid ink from tiny nozzles on a recording head and directly applying it to a recording medium. Therefore, during image recording, tiny ink droplets other than the ink involved in recording may float in the atmosphere. These tiny ink droplets, such as mist, that are not involved in recording may adhere to the area around the nozzles on the surface where the nozzles are formed on the recording head (the nozzle surface). When tiny ink droplets adhere to the nozzle surface, the straightness of the ink is hindered, causing the ejection direction to become distorted, a phenomenon known as "ejection distortion," which reduces the accuracy of ink ejection and tends to degrade the quality of the recorded image. Furthermore, the amount of ink droplets adhering to the nozzle surface tends to increase with longer recording times, so the image quality deteriorates further with increasing recording time.

[0005] To suppress the occurrence of ejection distortion, an inkjet recording apparatus has been proposed that includes a cleaning device that, for example, wipes the ejection port with the belly of a first wiper that is greatly bent, and then wipes the ejection port with the edge of a second wiper (Patent Document 1). [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2006-205715 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] The present inventors investigated an inkjet recording apparatus equipped with a cleaning device proposed in Patent Document 1. Specifically, they prepared an ink cartridge incorporating a recording head in which the ejection port surface was treated to be water-repellent and a protective tape, which is peeled off at the start of recording, was attached to the ejection port surface (water-repellent surface). The ink cartridge contained an aqueous ink containing pigment and resin. After peeling off the protective tape from this recording head and setting it in the inkjet recording apparatus, an image was recorded. As a result, it was found that ejection distortion was likely to occur immediately after peeling off the protective tape (immediately after opening). On the other hand, when an aqueous ink containing a self-dispersing pigment but no resin was used, ejection distortion was not observed immediately after opening. Furthermore, when an inkjet recording apparatus was prepared in which a recording head was equipped with a recording head in which the ejection port surface (water-repellent surface) was not attached to the protective tape and the ejection port surface was sealed with a cap, and an image was recorded using an aqueous ink containing pigment and resin, ejection distortion was not observed immediately after removing the cap.

[0008] Therefore, an object of the present invention is to solve the problems that arise when using a recording device equipped with a recording head on which a protective tape is attached to the discharge port surface which is a water-repellent surface, and a wiping means for the discharge port surface, and when using an aqueous ink containing pigment and resin. In other words, even in such cases, the present invention aims to provide an inkjet recording method that suppresses the occurrence of ink discharge distortion immediately after peeling off the protective tape (immediately after opening) and that is less prone to discharge distortion even after long-term use. Another object of the present invention is to provide an inkjet recording device to be used in this inkjet recording method. [Means for solving the problem]

[0009] In other words, the present invention provides an inkjet recording method comprising: an inkjet recording apparatus having a water-repellent treatment applied to a recording medium by using an inkjet recording apparatus having a water-repellent treatment applied to the [Effects of the Invention]

[0010] According to the present invention, it is possible to solve the problems that arise when using an inkjet recording device equipped with a recording head having a protective tape attached to the discharge port surface which is a water-repellent surface, and a wiping means for the discharge port surface, and when using an aqueous ink containing pigment and resin. In other words, even in such cases, it is possible to suppress the occurrence of ink discharge distortion immediately after peeling off the protective tape (immediately after opening) and to provide an inkjet recording method in which discharge distortion is less likely to occur even after long-term use. Furthermore, according to the present invention, it is possible to provide an inkjet recording device for use in this inkjet recording method. [Brief explanation of the drawing]

[0011] [Figure 1] This is a schematic perspective view showing the internal structure of one embodiment of the inkjet recording apparatus of the present invention. [Figure 2] This is a schematic perspective view showing an example of a maintenance unit. [Figure 3] This is a schematic perspective view showing an example of a recording unit. [Figure 4] This diagram schematically illustrates the movement of the wiper during the cleaning operation. [Modes for carrying out the invention]

[0012] The present invention will be described in more detail below with reference to preferred embodiments. In the present invention, when a compound is a salt, the salt exists in the ink dissociated into ions, but for convenience, it will be expressed as "contains a salt." Also, water-based ink for inkjet printers may be simply referred to as "ink." Unless otherwise specified, the physical properties are values ​​at room temperature (25°C).

[0013] The inventors prepared an ink cartridge in which a recording head is incorporated into an ink reservoir, and the ink discharge port surface is formed thereon, and the discharge port surface is treated with a water-repellent coating. Using the prepared ink cartridge, they analyzed the discharge distortion that occurs when ink containing pigment and resin is discharged from the recording head immediately after the protective tape has been removed and the cartridge opened. In ink cartridges in which the ink reservoir and recording head are integrally formed, a protective tape with an adhesive layer is usually attached to the discharge port surface of the recording head to suppress ink evaporation, and the cartridge is stored with the discharge port sealed. When using the cartridge for the first time (start of initial use), the ink cartridge packaged in a sealed container is opened, the protective tape is removed, and then it is installed in the recording device to start recording images. However, it was found that when the protective tape is removed, some of the adhesive that forms the adhesive layer may remain attached to the discharge port surface, and this remaining adhesive causes ink discharge distortion.

[0014] However, it was found that when using dye-based inks or pigment-based inks that do not contain resin, ejection distortion does not occur even if adhesive is present on the ejection port surface of the recording head. When the ejection port surface of recording heads that exhibited ink ejection distortion was observed after the protective tape was removed, residual adhesive was confirmed. In addition, the contact angles of the ejection port surface with various inks before the protective tape was applied, and the contact angles of the ejection port surface with various inks after the protective tape was applied and removed were measured. As a result, it was found that the contact angle with resin-containing inks differed significantly before and after the protective tape was applied. In other words, it is thought that the ejection port surface with adhesive present becomes more easily wetted by resin-containing inks, causing ejection distortion.

[0015] When using a recording unit that has an ink reservoir set in a head cartridge equipped with a recording head, it is not necessary to suppress the evaporation of ink from the ejection port, which is required in ink cartridges where the recording head is incorporated into the ink reservoir. Therefore, when using a recording unit that has an ink reservoir set in a head cartridge equipped with a recording head, ink ejection irregularities caused by residual adhesive do not occur.

[0016] The inventors further investigated the wiping conditions for the ejection port surface. As a result, they found that by using the configuration shown below, the occurrence of ejection distortion immediately after peeling off the protective tape is suppressed, and that ejection distortion is less likely to occur even after long-term use, leading to the present invention. Specifically, the inkjet recording method of the present invention uses an inkjet recording device comprising an ink containing a pigment and a resin, an ink storage unit for storing the ink, a recording head incorporated into the ink storage unit, and a wiping means for wiping. The recording head is attached to the ink storage unit and has an ejection port surface in which an ejection port for ejecting ink is formed, and this ejection port surface is treated to be water-repellent. The wiping means is a means for wiping the ejection port surface of the recording head. A protective tape having an adhesive layer formed of an adhesive is attached to the ejection port surface of the recording head in order to suppress the evaporation of ink from the ejection port, and this protective tape is peeled off when the inkjet recording device and recording head are used for the first time. Furthermore, the inkjet recording method of the present invention has a first cleaning sequence that includes a first wiping step and a second wiping step, which are performed sequentially, in which the discharge port surface is wiped using a blade-shaped wiper. The first wiping step is a step of bending the wiper and wiping the discharge port surface with the belly of the wiper, and the second wiping step is a step of wiping the discharge port surface with the edge of the wiper.

[0017] In the first wiping step, the wiper is bent relatively largely, and the abdomen of the wiper is brought into sliding contact with the ejection port surface. Thereby, the ink droplets on the ejection port surface can be spread and made to blend with the adhered adhesive. In the subsequent second wiping step, the wiper is not bent so largely or hardly bent at all, and wiping is performed with the edge portion (portion other than the abdomen) of the wiper contacting the ejection port surface. Thereby, the mixture of the ink droplets and the adhesive that were made to blend in the first wiping step can be scraped off. A large amount of pigment also adheres to the ejection port surface. The pigment, which is a hard granular substance, acts as a so-called "abrasive" to scrape off the firmly adhered adhesive that cannot be completely scraped off only by the edge portion of the wiper by being dragged by the wiper. Thus, after spreading the ink droplets and making them blend with the adhesive in the first wiping step of wiping with the abdomen of the wiper, the adhesive can be efficiently scraped off in the second wiping step of wiping with the edge of the wiper. As a result, it is considered that the occurrence of ink bleeding immediately after opening is suppressed and the occurrence of ink bleeding is less likely to occur even after long-term use.

[0018] If only the first wiping step is performed without performing the second wiping step, the adhesive cannot be scraped off and removed, so the occurrence of ink bleeding cannot be suppressed. Also, if only the second wiping step is performed without performing the first wiping step, the ink droplets and the adhesive have not blended, so the adhesive cannot be efficiently removed and the occurrence of ink bleeding cannot be suppressed. <于 <于

[0019] <于 <Inkjet Recording Method and Inkjet Recording Apparatus> The present invention relates to an inkjet recording method that uses an inkjet recording apparatus comprising ink, an ink storage section for storing the ink, a recording head, and a wiping means for wiping the ejection port surface of the recording head. The ink contains a pigment and a resin. The recording head is a recording head incorporated into the ink storage section, having an ejection port surface formed with an ejection port for ejecting ink supplied from the ink storage section, and the ejection port surface is treated to be water-repellent. The present invention relates to an inkjet recording method that includes the step of applying the ink ejected from the ejection port of the recording head to a recording medium to record an image. A protective tape having an adhesive layer formed of an adhesive, which is peeled off during use, is attached to the ejection port surface of the recording head. Furthermore, the present invention relates to an inkjet recording method that includes a first cleaning sequence including a first wiping step and a second wiping step performed sequentially, in which the ejection port surface is wiped using a blade-shaped wiper. The first wiping step is the step of bending the wiper and wiping the ejection port surface with the belly of the wiper. The second wiping step is the step of wiping the ejection port surface with the edge of the wiper.

[0020] Furthermore, the inkjet recording apparatus of the present invention includes ink, an ink storage unit for storing the ink, a recording head, and wiping means for wiping the discharge port surface. The ink contains a pigment and a resin. The recording head is a recording head incorporated in the ink storage unit and having a discharge port surface formed with discharge ports for discharging the ink supplied from the ink storage unit, and the discharge port surface is subjected to a water-repellent treatment. The inkjet recording method carried out using this recording apparatus has a step of applying the ink discharged from the discharge ports of the recording head to a recording medium to record an image. A protective tape formed of an adhesive and having an adhesive layer that is peeled off during use is attached to the discharge port surface of the recording head. Further, the inkjet recording method has a first cleaning sequence including a first wiping step and a second wiping step that are continuously carried out using one blade-shaped wiper to wipe the discharge port surface. The first wiping step is a step of bending the wiper and wiping the discharge port surface with the belly of the wiper. And the second wiping step is a step of wiping the discharge port surface with the edge portion of the wiper.

[0021] (Inkjet recording apparatus) Figure 1 is a schematic perspective view showing the internal structure of one embodiment of the ink recording device of the present invention. As shown in Figure 1, the inkjet recording device 1010 of this embodiment comprises a carriage 1020, a transport unit 1060, and a maintenance unit 1030. The carriage 1020 is equipped with a recording head that ejects ink and an ink cartridge (not shown). The transport unit 1060 is a unit that transports recording media fed from the paper feeding unit 1070. The maintenance unit 1030 is a unit that maintains the recording head mounted on the carriage. The inkjet recording device 1010 further comprises a tube 1090 that supplies ink to the recording head and a main tank 1080 that contains the ink. The transport unit 1060 is located on one end of the carriage equipped with the recording head in the main scanning direction 21, and the maintenance unit 1030 is located on the other end of the main scanning direction 21. The drive from the drive source (not shown) of the transport unit 1060 is transmitted to the maintenance unit 1030 by a drive train.

[0022] Recording media are fed one sheet at a time from the paper feed unit 1070 and transported by the transport unit 1060 in the recording media ejection direction 11. The carriage 1020, equipped with a recording head, performs a reciprocating motion in a direction approximately perpendicular to the recording media ejection direction 11 (main scanning direction 21), ejecting ink from the recording head to record onto the recording media. When recording, the carriage 1020 starts recording from the maintenance unit 1030 side, moves to the transport unit 1060 side, and then turns back to the maintenance unit 1030 side. At the position of the maintenance unit 1030, the recording head performs a preliminary ejection into the cap 1031 inside the maintenance unit. This reciprocating motion constitutes one scan of the carriage 1020, and by repeating this motion multiple times on the recording media, an image is recorded over the entire recording media.

[0023] Figure 2 is a schematic perspective view showing an example of a maintenance unit. The inkjet recording device is equipped with a recording head for black and a recording head for three colors. The cap 1031 and wiper 1032 are configured for each recording head. When the cam slider 1033 is operated, the cam surface of the cam slider 1033 comes into contact with the follower surface of each component, causing each component to operate independently.

[0024] Preferably, an inkjet recording device further includes a second ink storage section, such as a main tank, which has a larger capacity than the first ink storage section, such as a sub-tank, and a tube through which ink flows between the second ink storage section and the first ink storage section. Considering usage patterns such as remote work at home, it is important to reduce the frequency of ink cartridge replacement as well as miniaturize the device. For this reason, by further providing a second ink storage section, such as a main tank, it is possible to reduce the frequency of ink replacement while avoiding increasing the size of the device body. Hereinafter, an inkjet recording device in which only the first ink storage section, such as a sub-tank attached to the recording head, is provided as the ink storage section will also be referred to as the "first device configuration." In the case of the first device configuration, when the ink stored inside the ink storage section is consumed, it is replaced with another ink storage section (an ink storage section filled with ink). Therefore, compared to the second device configuration, the main tank and tube can be omitted, making it possible to lighten the inkjet recording device. Furthermore, an inkjet recording device that includes a second ink storage section, such as a main tank with a larger capacity than the sub-tank, is also referred to as a "second device configuration." In the case of the second device configuration, for example, the ink storage section 10 and the second ink storage section, such as the main tank, can be connected by forming a connection part for a tube on the tank lid 33 of the recording unit 8 shown in Figure 3.

[0025] In the second device configuration, the frequency of ink replacement is reduced compared to the first device configuration, resulting in a longer period during which ink remains stationary in the main tank. Furthermore, in the case of pigment ink, a longer period of stationary retention makes the pigment more prone to settling. The decrease in ejection performance due to adhesion is caused by the ink drying in the flow path and the pigment agglomerating, and this becomes more pronounced when using ink with a high pigment content. Moreover, depending on the usage conditions, the ejection distortion after long-term use of the second device configuration is often worse than that after long-term use of the first device configuration. In contrast, the inkjet recording method of the present invention makes it possible to suppress ejection distortion even when using the second device configuration, thus achieving both a reduction in ink replacement frequency and suppression of ejection distortion after long-term use.

[0026] Figure 3 is a schematic perspective view showing an example of a recording unit (ink cartridge). As shown in Figure 3, the recording unit 8 has an ink storage section 10, which is a housing made of a material such as thermoplastic resin, and a recording head 12 incorporated into the ink storage section 10. In other words, the recording head 12 is integrally formed with the ink storage section 10. Since the recording head 12 is bonded to the ink storage section 10 without the interposition of other members, the entire recording unit 8 is miniaturized and lightweight. By using such a recording unit 8, the entire inkjet recording device can be miniaturized and lightweighted. Examples of heat sinks include those made of materials such as metal oxides such as alumina. Although it is not necessary to interpose other members such as heat sinks between the ink storage section 10 and the recording head 12, an adhesive layer formed by adhesive or the like may be present to fix the recording head 12 to the ink storage section 10. The ink storage section 10 contains ink containing pigment and resin. The recording head 12 has an ejection port surface 30 in which an ejection port is formed for ejecting ink supplied from the ink storage section 10. A protective tape 50, which has an adhesive layer made of adhesive, is attached to the ejection port surface 30 of the recording head 12 and is peeled off when the ink cartridge is first used. By providing tabs 40 at the end of the protective tape 50, which are non-adhesive parts not attached to the recording head, the protective tape can be easily peeled off.

[0027] There are several ink ejection methods for recording heads, including methods that use mechanical energy generated by a piezoelectric element to eject the ink, and methods that use thermal energy generated by an electrothermal converter (heater) to eject the ink. While either ink ejection method can be used, the method that uses thermal energy to eject the ink is more preferable.

[0028] The discharge surface of the recording head is treated to be water-repellent. Methods for treating the discharge surface to be water-repellent include applying a water-repellent material by spraying, or depositing the water-repellent material by vacuum deposition or plasma polymerization. The water repellency of the discharge surface can be evaluated by measuring the water contact angle. A water contact angle of 70° or higher can be judged as "water-repellent," and a water contact angle of 90° or higher is preferable. The contact angle with water can be measured using pure water (ion-exchanged water) and a general contact angle meter. An example of a contact angle meter is an automatic contact angle measuring machine (product name "CA-W," manufactured by Kyowa Interface Science).

[0029] Examples of water-repellent materials for treating the discharge port surface include compounds of fluororesins. The water-repellent surface is preferably formed as a uniform resin film made of these materials, and it is preferable that this resin film does not contain metals such as nickel. Examples of fluororesins include polytetrafluoroethylene resins and fluororesins having a cyclic structure. Specific examples of fluororesin compounds include the trade names "Polyflon PTFE" (manufactured by Daikin Industries), "Teflon® PTFE" (manufactured by DuPont), and "Cytop" (manufactured by Asahi Glass). Furthermore, other resins containing fluorine atoms, such as fluorinated epoxy resins, fluorinated polyimide resins, fluorinated polyamide resins, fluorinated acrylic resins, fluorinated urethane resins, fluorinated siloxane resins, and modified resins thereof, can be used.

[0030] As a water-repellent material, compounds containing silicon (Si) atoms or silicone resins may be used. In particular, because a high degree of water repellency and durability can be obtained, it is preferable to use hydrolyzable silane compounds having fluoroalkyl groups and condensates of hydrolyzable silane compounds having cationic polymerizable groups as water-repellent materials. Alternatively, a resin obtained by curing this condensate by irradiation with active energy rays such as ultraviolet light may be used. These hydrolyzable silane compounds have hydrolyzable groups such as alkoxy groups in their molecular structure. Examples of cationic polymerizable groups include cyclic ether groups and cyclic vinyl ether groups.

[0031] The protective tape is a component used to prevent evaporable components in the ink, such as water, from evaporating from the ejection port of the recording head. The protective tape has an adhesive layer formed of an adhesive. Examples of adhesives include silicone-based adhesives, acrylic-based adhesives, rubber-based adhesives, and urethane-based adhesives. Among these, silicone-based adhesives or acrylic-based adhesives are preferred, and acrylic-based adhesives are even more preferred. Rubber-based adhesives generally have low strength. Also, urethane-based adhesives may deteriorate due to the ink and peel off during storage, making them more likely to dissolve in the ink. As a result, liquid components such as water in the ink may evaporate, and pigments and resins may aggregate in the ink flow path, which can easily cause ejection distortion. In contrast, acrylic-based adhesives are preferred because, compared to other adhesives, the contact angle between the ejection port surface and the ink after peeling does not decrease as easily. The adhesive layer is formed, for example, on the surface of a sheet-like or film-like substrate. As the substrate, resin materials such as polyethylene terephthalate (PET) can be used.

[0032] It is preferable that the acrylic adhesive contains a metal chelating crosslinking agent and that the pH of the ink at 25°C is 8.6 or higher. Acrylic adhesives containing a metal chelating crosslinking agent are prone to degradation when in contact with ink with a high pH for a long period of time, as the coordinated metal detaches. As a result, they are more easily wiped off with a wiper, which is preferable.

[0033] The inkjet method of this embodiment has a first cleaning sequence in which the ejection port surface of the recording head is wiped using a blade-shaped wiper. This first cleaning sequence includes a first wiping step and a second wiping step that are performed consecutively. Figure 4 is a schematic diagram illustrating the movement of the wiper during the cleaning operation. (a) is a schematic diagram illustrating the movement of the wiper in the first wiping step, and (b) is a schematic diagram illustrating the movement of the wiper in the second wiping step. In the first wiping step, as shown in Figure 4(a), the amount of wiper penetration P1 into the recording head 12 is set to a predetermined value by changing the height of the carriage on which the recording head 12 is mounted, and the wiper (pre-bent wiper 15) is bent relatively significantly. Then, the ejection port surface 30 of the recording head 12 is wiped with the belly 25 of the bent wiper 20. This spreads the ink droplets on the ejection port surface 30 and allows them to blend with the attached adhesive 60.

[0034] In the second wiping step, as shown in Figure 4(b), the edge of the wiper 20 is used to wipe the ejection port surface 30 of the recording head 12. In the second wiping step, for example, the carriage is positioned higher than in the first wiping step, and the amount of wiper penetration P2 into the recording head 12 is set to be smaller than the amount of wiper penetration P1 in the first wiping step. This allows the mixture 65 of ink droplets and adhesive that was spread in the first wiping step to be scraped off.

[0035] The amount of wiper penetration P1 during the first wiping process is preferably 1.8 mm or less (Figure 4(a)). If the amount of wiper penetration P1 exceeds 1.8 mm, the force applied due to contact increases, and the discharge port surface may become easily damaged. Furthermore, prolonged use may cause the water-repellent surface to wear away, reducing the effect of suppressing discharge distortion. The amount of wiper penetration P1 during the first wiping process is preferably 1.0 mm or more. The amount of wiper penetration P2 during the second wiping process is preferably 0.3 mm or more (Figure 4(b)). If the amount of wiper penetration P2 is less than 0.3 mm, the removal efficiency of adhesives, etc., may decrease slightly, and the effect of suppressing discharge distortion may decrease. The amount of wiper penetration P2 during the second wiping process is preferably less than 1.0 mm. In particular, it is preferable that the amount of wiper penetration in the first wiping step is 1.0 mm or more and 1.8 mm or less, and that the amount of wiper penetration in the second wiping step is 0.3 mm or more and 1.0 mm or less.

[0036] The interval between the end of the first wiping process and the start of the second wiping process is preferably 5 seconds or more and 15 seconds or less. If the above interval (time difference) is less than 5 seconds, the ink spread on the nozzle surface by the first wiping process may not blend sufficiently with the adhesive, which may slightly reduce the efficiency of removing the adhesive and slightly reduce the effect of suppressing dislodgement. On the other hand, if the above interval (time difference) is more than 15 seconds, liquid components such as water in the ink adhering to the nozzle surface may evaporate, making the ink more likely to solidify. This may slightly reduce the efficiency of removing the adhesive and slightly reduce the effect of suppressing dislodgement.

[0037] It is preferable to perform the first wiping step and the second wiping step at least twice each. If the first wiping step is performed less than twice, the ink droplets on the nozzle surface may not spread sufficiently, and the effect of suppressing discoloration may decrease. Also, if the second wiping step is performed less than twice, it may be difficult to sufficiently remove adhesive and other substances adhering to the nozzle surface, and the effect of suppressing discoloration may decrease.

[0038] The material of the wiper is preferably one with rubber elasticity, such as a rubber material formed from urethane resin (urethane rubber). The thickness of the wiper is preferably 0.5 mm to 1.5 mm, and more preferably 0.8 mm to 1.2 mm. If the thickness of the wiper is less than 0.5 mm, the efficiency of removing adhesives and other substances may be slightly reduced. On the other hand, if the thickness of the wiper is greater than 1.5 mm, the discharge surface may be easily damaged. Furthermore, prolonged use may cause the water-repellent surface to wear down, reducing the effect of suppressing discharge distortion. The height of the wiper (length from the fixed position of the wiper to the tip of the wiper) is preferably 5.0 mm to 20.0 mm, and more preferably 5.0 mm to 15.0 mm.

[0039] The speed at which the discharge nozzle surface is wiped using the wiper is preferably between 100 mm / s and 150 mm / s. If the wiping speed is less than 100 mm / s, the discharge nozzle surface may be easily damaged. Furthermore, prolonged use may cause the water-repellent surface to wear away, reducing the effect of suppressing discharge distortion. On the other hand, if the wiping speed exceeds 150 mm / s, the efficiency of removing adhesives and other substances may decrease slightly, reducing the effect of suppressing discharge distortion. The wiping speeds for the first wiping step, the second wiping step, and the third wiping step described later may be set within the above ranges, and may be the same or different.

[0040] The first cleaning sequence is preferably performed at least immediately after the protective tape has been removed. Specifically, it is preferable to perform the first cleaning sequence after removing the protective tape but before recording. If a certain amount of time has passed since the protective tape was removed, the adhesive remaining on the discharge port surface may dry and harden, making it difficult to remove. This may reduce the effectiveness of suppressing discharge distortion.

[0041] The inkjet recording method of this embodiment preferably further includes a second cleaning sequence performed after the first cleaning sequence. This second cleaning sequence preferably includes a third wiping step in which the ejection port surface is wiped with the edge of a wiper while the recording head is heated. This third wiping step can be performed in the same procedure as the second wiping step described above, except that the recording head is heated. Wiping while heating the recording head makes it easier to peel off adhesive that has deteriorated due to heat, thereby improving the efficiency of adhesive removal.

[0042] To heat the recording head, a heating means capable of heating the ink inside the recording head to a temperature higher than the ambient recording temperature, such as room temperature (25°C), can be used. Examples of such heating means include an ink temperature adjustment heater positioned to contact the recording head, and an ink ejection heater. To heat the ink using an ink ejection heater, for example, a current that does not eject ink can be repeatedly applied. The temperature of the ink inside the recording head should be higher than the ambient temperature (25°C), preferably between 40°C and 70°C, and more preferably between 50°C and 70°C.

[0043] The first wiping step is preferably performed only in the first cleaning sequence. That is, the second cleaning sequence preferably does not substantially include a step of significantly bending the wiper and wiping the discharge port surface with the belly of the wiper. If the step of increasing the amount of wiper penetration and wiping the discharge port surface with the belly of the wiper is also performed in the second cleaning sequence, the discharge port surface may become easily damaged. Furthermore, prolonged use may cause the water-repellent surface to wear down, reducing the effect of suppressing discharge distortion. However, after performing a recording head recovery operation by suction or recovery, it is preferable to wipe the discharge port surface with the edge of the wiper (perform the second wiping step).

[0044] (Water-based ink) The inkjet recording method of the present invention includes the step of recording an image by using an ink containing a pigment and a resin, and applying the ink ejected from an ejection port to a recording medium. The ink includes, for example, black ink, cyan ink, magenta ink, and yellow ink. In the present invention, it is sufficient to perform the step of applying the ink to the recording medium, and no other processing (such as a step of applying a reaction solution that reacts with the ink, a step of curing the image by irradiation with active energy rays, or a step of heating the image) is required. Therefore, the ink does not need to contain a reactant or a component that is cured by active energy rays, nor is it necessary to use the ink and reaction solution together. The components that make up the ink will be described below.

[0045] [Colorants] Pigments are used as the colorants for the ink. By using ink containing pigments, adhesives that are firmly attached to the nozzle surface can be scraped off. Examples of pigments include inorganic pigments such as carbon black; and organic pigments such as azo pigments, phthalocyanine pigments, quinacridone pigments, isoindolinone pigments, imidazolon pigments, diketopyrrolopyrrole pigments, dioxazine pigments, and perinone pigments. Among these, carbon black is preferred. Because carbon black is particularly hard among pigments, using ink containing carbon black allows for more efficient scraping off of adhesives attached to the nozzle surface.

[0046] The pigment content (by mass) in the aqueous ink is preferably 0.50% by mass or more and 10.00% by mass or less, and more preferably 1.00% by mass or more and 8.00% by mass or less, based on the total mass of the ink.

[0047] Examples of pigment dispersion methods include resin-dispersed pigments that use a resin (resin dispersant) as a dispersant, and self-dispersing pigments in which hydrophilic groups are bonded to the surface of the pigment particles. In addition, resin-bonded pigments in which organic groups containing resin are chemically bonded to the surface of the pigment particles, and microcapsule pigments in which the surface of the pigment particles is coated with resin or the like can be used. Among these, it is particularly preferable to use resin-dispersed pigments that use a resin dispersant having hydrophobic and hydrophilic parts, in which the hydrophobic part of the resin dispersant is adsorbed onto the surface of the pigment particles, and the pigment is dispersed by the hydrophilic part.

[0048] As a resin dispersant for dispersing pigments in an aqueous medium, it is preferable to use one that can disperse pigments in the aqueous medium through the action of anionic groups. As the resin dispersant, resins described later, especially water-soluble resins, can be used. When using resin-dispersed pigments, it is preferable that the pigment content (mass%) in the ink is 0.3 to 10.0 times the mass ratio of the resin dispersant content (mass%).

[0049] Self-dispersing pigments can be those in which anionic groups such as carboxylic acid groups, sulfonic acid groups, and phosphonic acid groups are bonded directly to the surface of the pigment particles or via other atomic groups (-R-). The anionic group may be either acidic or salt-type, and if it is salt-type, it may be in a partially dissociated state or a fully dissociated state. When the anionic group is salt-type, examples of cations that become counterions include alkali metal cations, ammonium, and organic ammonium. Specific examples of other atomic groups (-R-) include linear or branched alkylene groups with 1 to 12 carbon atoms; arylene groups such as phenylene and naphthylene groups; carbonyl groups; imino groups; amide groups; sulfonyl groups; ester groups; and ether groups. Combinations of these groups may also be used.

[0050] [resin] The ink contains a resin, such as a water-soluble resin. The resin content (mass%) in the ink is preferably 0.10% to 20.00% by mass, and more preferably 0.50% to 15.00% by mass, based on the total mass of the ink. The resin can be added to the ink (i) to stabilize the dispersion state of the pigment, i.e., as a resin dispersant or its auxiliary. It can also be added to the ink (ii) to improve various properties of the recorded image. Examples of resin forms include block copolymers, random copolymers, graft copolymers, and combinations thereof. The resin may be a water-soluble resin that can dissolve in an aqueous medium, or it may be resin particles dispersed in an aqueous medium. Among these, a water-soluble resin is preferred, and this water-soluble resin is preferably a resin dispersant for dispersing the pigment.

[0051] Examples of resins include acrylic resins, urethane resins, and olefin resins. Among these, acrylic resins and urethane resins are preferred, and acrylic resins are even more preferred. As for acrylic resins, those having hydrophilic units as hydrophilic parts and hydrophobic units as hydrophobic parts as constituent units are preferred. Hydrophilic units are units having hydrophilic groups such as anionic groups. Hydrophilic units can be formed, for example, by polymerizing hydrophilic monomers having hydrophilic groups. Examples of hydrophilic monomers having hydrophilic groups include acidic monomers having carboxylic acid groups such as (meth)acrylic acid, itaconic acid, maleic acid, and fumaric acid; anionic monomers such as anhydrides and salts of these acidic monomers; and so on. Examples of cations constituting salts of acidic monomers include ions such as lithium, sodium, potassium, ammonium, and organic ammonium. Hydrophobic units are units that do not have hydrophilic groups such as anionic groups. Hydrophobic units can be formed, for example, by polymerizing hydrophobic monomers that do not have hydrophilic groups such as anionic groups. Examples of hydrophobic monomers include monomers having aromatic rings such as styrene, α-methylstyrene, and benzyl (meth)acrylate; and (meth)acrylic acid ester monomers such as methyl (meth)acrylate, butyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate.

[0052] In particular, acrylic resins having hydrophilic units derived from (meth)acrylic acid and hydrophobic units derived from at least one selected from the group consisting of monomers having aromatic rings and (meth)acrylic acid ester monomers are preferred. Especially preferred are acrylic resins having hydrophilic units derived from (meth)acrylic acid and hydrophobic units derived from at least one monomer of styrene and α-methylstyrene. Because these acrylic resins readily interact with pigments, they can be suitably used as resin dispersants for dispersing pigments.

[0053] Urethane resins can be obtained, for example, by reacting polyisocyanate and polyol. Alternatively, they may be obtained by further reacting a chain extender. Examples of olefin resins include polyethylene and polypropylene.

[0054] In this specification, "water-soluble resin" means that when the resin is neutralized with an equivalent amount of alkali to its acid value, it exists in an aqueous medium without forming particles whose particle size can be measured by dynamic light scattering. Whether or not a resin is water-soluble can be determined according to the following method. First, a liquid containing the resin (resin solids content: 10% by mass) is prepared, neutralized with an alkali equivalent to its acid value (such as sodium hydroxide or potassium hydroxide). Next, the prepared liquid is diluted 10 times (by volume) with pure water to prepare a sample solution. Then, when the particle size of the resin in the sample solution is measured by dynamic light scattering, if no particles with a particle size are measured, the resin can be determined to be water-soluble. On the other hand, if particles with a particle size are measured, the resin can be determined to be "resin particles" (i.e., "water-dispersible resin"). The measurement conditions in this case can be, for example, as follows. [Measurement conditions] SetZero: 30 seconds Number of measurements: 3 Measurement time: 180 seconds

[0055] As a particle size distribution analyzer, a dynamic light scattering particle size analyzer (for example, product name "UPA-EX150," manufactured by Nikkiso) can be used. Of course, the particle size distribution analyzer and measurement conditions used are not limited to those mentioned above.

[0056] [Aqueous medium] The ink is an aqueous ink containing at least water as an aqueous medium. The ink may contain an aqueous medium which is water or a mixed solvent of water and a water-soluble organic solvent. It is preferable to use deionized water (ion-exchanged water) as the water. The water content (mass%) in the ink is preferably 50.00% by mass or more and 95.00% by mass or less based on the total mass of the ink. As the water-soluble organic solvent, any of those usable for inkjet inks, such as alcohols, glycols, (poly)alkylene glycols, nitrogen-containing compounds, and sulfur-containing compounds, can be used. The water-soluble organic solvent content (mass%) in the ink is preferably 3.00% by mass or more and 50.00% by mass or less based on the total mass of the ink.

[0057] [Surfactants] The ink preferably further contains a surfactant. Examples of surfactants include anionic surfactants, cationic surfactants, nonionic surfactants, amphoteric surfactants, and other surfactants. Among these, the use of a nonionic surfactant is preferred.

[0058] The surfactant content (mass%) in the ink is preferably 0.10% by mass or more and 5.00% by mass or less, and more preferably 0.10% by mass or more and 2.00% by mass or less, based on the total mass of the ink. In particular, it is especially preferable that it be 0.10% by mass or more and 1.00% by mass or less.

[0059] [Other ingredients] In addition to the above components, the ink may optionally contain water-soluble organic compounds that are solid at room temperature, such as polyhydric alcohols like trimethylolpropane and trimethylolethane, urea and its derivatives, and sugars and their derivatives. Furthermore, the ink may optionally contain various additives such as defoamers, pH adjusters, viscosity adjusters, rust inhibitors, preservatives, fungicides, antioxidants, and reduction inhibitors.

[0060] [Ink properties] The ink is an aqueous ink for use in inkjet systems. Therefore, from the viewpoint of reliability, it is preferable to appropriately control its physical properties. Specifically, the static surface tension of the ink at 25°C is preferably 28 mN / m or more and 45 mN / m or less. The viscosity of the ink at 25°C is preferably 1.0 mPa·s or more and 5.0 mPa·s or less, and more preferably 1.0 mPa·s or more and 3.0 mPa·s or less. The pH of the ink at 25°C is preferably 5.0 or more and 9.5 or less. As mentioned above, when using a protective tape having an adhesive layer formed of an acrylic adhesive containing a metal chelating crosslinking agent, the pH of the ink is preferably 8.6 or higher, and more preferably 8.9 or more and 9.3 or less. [Examples]

[0061] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited in any way by the following examples unless it exceeds the gist of the invention. Unless otherwise specified, amounts of components indicated in "parts" and "%" are based on mass.

[0062] <Preparation of Pigment Dispersion> (Pigment dispersion 1) A solution of 5.0g concentrated hydrochloric acid dissolved in 5.5g water was cooled to 5°C, and 1.5g of 4-amino-1,2-benzenedicarboxylic acid was added. The container of this solution was placed in an ice bath and stirred to maintain the solution temperature below 10°C, while a solution of 1.8g sodium nitrite dissolved in 9.0g of 5°C water was added. After stirring for 15 minutes, the specific surface area was 250m². 26.0 g of carbon black with a DBP oil absorption capacity of 140 mL / 100 g was added under stirring. The mixture was stirred for another 15 minutes to obtain a slurry. The obtained slurry was filtered through filter paper (product name "Standard Filter Paper No. 2", manufactured by Advantec), the particles were thoroughly washed with water, and the mixture was dried in an oven at 110°C. Subsequently, sodium ions were replaced with potassium ions by ion exchange to obtain a self-dispersing pigment in which two -C6H3-(COOK) groups were bonded to the surface of the pigment particles. The pigment content was adjusted by adding an appropriate amount of water to obtain pigment dispersion 1 with a pigment content of 15.00%.

[0063] (Pigment dispersion 2) A styrene-acrylic acid copolymer with an acid value of 90 mg KOH / g and a weight-average molecular weight of 10,000 was neutralized with a 10% potassium hydroxide aqueous solution. Carbon black (specific surface area 220 m²) 2 A mixture was obtained by mixing 10.0 parts of ( / g, DBP oil absorption 100 mL / 100 g), 2.0 parts of neutralized styrene-acrylic acid copolymer (solids), and 88.0 parts of deionized water. The mixture obtained was dispersed for 1 hour using a sand grinder, and then centrifuged to remove coarse particles. Furthermore, it was pressure filtered through a 3.0 μm pore size microfilter (manufactured by Fujifilm) to obtain pigment dispersion 2, in which carbon black was dispersed in water by the resin. The pigment content in pigment dispersion 2 was 15.00%, and the resin dispersant content was 3.00%.

[0064] (Pigment dispersion 3) A styrene-acrylic acid copolymer with an acid value of 120 mg KOH / g and a weight-average molecular weight of 10,000 was neutralized with a 10% potassium hydroxide aqueous solution. 10.0 parts of CI pigment blue 15:3, 3.0 parts of the neutralized styrene-acrylic acid copolymer (solids), and 85.0 parts of deionized water were mixed to obtain a mixture. The mixture obtained was dispersed for 1 hour using a sand grinder, and then centrifuged to remove coarse particles. Furthermore, it was pressure filtered through a 3.0 μm pore size microfilter (manufactured by Fujifilm) to obtain pigment dispersion 3, in which CI pigment blue 15:3 was dispersed in water by the resin. The pigment content in pigment dispersion 3 was 15.00%, and the resin dispersant content was 3.00%.

[0065] (Pigment dispersion 4) Pigment dispersion 4 was obtained in the same manner as pigment dispersion 3 described above, except that CI pigment red 122 was used instead of CI pigment blue 15:3. The pigment content in pigment dispersion 4 was 15.00%, and the resin dispersant content was 3.00%.

[0066] (Pigment dispersion 5) Pigment dispersion 5 was obtained in the same manner as pigment dispersion 3 described above, except that CI pigment yellow 74 was used instead of CI pigment blue 15:3. The pigment content in pigment dispersion 5 was 15.00%, and the resin dispersant content was 3.00%.

[0067] <Preparation of dye aqueous solution> CI Direct Blue 199 was dissolved in deionized water, and then acid was added to precipitate the dye. The precipitated dye was filtered and separated to obtain a wet cake of the free acid-type dye. The obtained wet cake was added to deionized water, and an aqueous solution containing an equimolar amount of sodium hydroxide to the anionic groups of the dye was added to neutralize all the anionic groups and dissolve the dye. An appropriate amount of deionized water was added to obtain an aqueous dye solution with a dye content of 15.00%.

[0068] <Preparation of resin> (Acrylic resin 1) Acrylic resin 1 was synthesized by copolymerizing 81.0 parts of styrene and 19.0 parts of acrylic acid according to a conventional method. The carboxylic acid groups of acrylic resin 1 were neutralized with potassium hydroxide in an equimolar amount equal to the acid value of acrylic resin 1, and an appropriate amount of pure water was added to obtain a liquid containing acrylic resin 1 with a resin content of 20.00%. The acid value of acrylic resin 1 was 148 mg KOH / g, and the weight-average molecular weight measured by gel permeation chromatography was 10,000.

[0069] (urethane resin) A four-necked flask equipped with a stirrer, thermometer, nitrogen gas inlet tube, and reflux tube was prepared. 41.5 parts isophorone diisocyanate, 40.6 parts polypropylene glycol, 15.7 parts dimethylolpropionic acid, and 300.0 parts methyl ethyl ketone were added to this four-necked flask. The mixture was then reacted at 80°C for 6 hours under a nitrogen atmosphere. Next, 3.6 parts polyamine was added and the mixture was reacted at 80°C to obtain a reaction solution. After cooling the reaction solution to 40°C, deionized water was added, and potassium hydroxide aqueous solution was added while stirring at high speed with a homomixer to obtain a liquid. Methyl ethyl ketone was removed from the liquid obtained by heating and reducing pressure to obtain a liquid containing urethane resin (solid content) with a urethane resin (solid content) content of 20.00%.

[0070] (Acrylic resin 2) A solution was prepared by mixing 79.4 parts of deionized water and 0.2 parts of potassium persulfate. An emulsion was prepared by mixing 16.7 parts of butyl methacrylate, 0.4 parts of methacrylic acid, 3.0 parts of ethylene glycol methyl diacrylate, and 0.3 parts of product name "Aqualon KH-05" (manufactured by Daiichi Kogyo Seiyaku). Under a nitrogen atmosphere, the prepared emulsion was added dropwise to the above solution over 1 hour, and the polymerization reaction was carried out with stirring at 80°C, followed by stirring for 2 hours. After cooling to room temperature, deionized water and potassium hydroxide aqueous solution were added to adjust the pH to 8.5, and a liquid containing acrylic resin 2 with a resin particle content of 20.00% was obtained.

[0071] <Ink preparation> Each ink was prepared by mixing the components (unit: %) shown in the upper section of Tables 1-1 and 1-2, stirring thoroughly, and then pressure filtering through a 3.0 μm pore size microfilter (manufactured by Fujifilm). In Tables 1-1 and 1-2, the values ​​attached to polyethylene glycol indicate the number-average molecular weight, and "Acetylenel E100" is the trade name of an acetylene glycol-based nonionic surfactant (manufactured by Kawaken Fine Chemicals). The pigment content and resin content in the obtained inks, as well as the pH of the ink at 25°C, are shown in the lower section of Tables 1-1 and 1-2. The pH of the ink was adjusted by adding a 1 mol / L aqueous acetic acid solution or an 8 mol / L aqueous potassium hydroxide solution. The amount of aqueous acetic acid solution or aqueous potassium hydroxide solution used for pH adjustment is shown as part of the pure water content.

[0072] TIFF0007830565000001.tif133170

[0073] TIFF0007830565000002.tif132170

[0074] <Recording Unit (Ink Cartridge) Configuration> A recording unit (ink cartridge) was prepared in which a recording head that ejects ink by applying thermal energy without a heat sink, without using a heat sink, was directly attached to the ink storage section 10, as shown in Figure 3. The recording element substrate constituting the recording head has a row of ejection ports arranged with an array density of 600 dpi and 384 ejection ports. The mass of the ink droplet ejected from one ejection port is 5.5 ng. As the recording head, an epoxy resin was used in which the ejection port surface was treated with a water-repellent agent. The water-repellent agent is a resin cured from a condensate of a hydrolyzable silane compound having a fluoroalkyl group (a compound having a fluoromethyl group and a methoxy group) and a hydrolyzable silane compound having a cationic polymerizable group (a compound having an epoxy group and an ethoxy group). Then, a protective tape with an adhesive layer was attached to the ejection port surface of the recording head to manufacture the recording unit. The characteristics of the obtained recording unit are shown in Table 2.

[0075] TIFF0007830565000003.tif62170

[0076] <Rating> As Device 1, we prepared a Canon PIXUS TS5130S inkjet recording device, which replaces the ink stored inside the ink cartridge with a new ink cartridge when the ink is consumed. As Device 2, we prepared a Canon G3370 inkjet recording device, which connects an ink cartridge on a carriage (sub-tank) and an ink cartridge mounted inside the device (main tank) with an ink-flow tube. These inkjet recording devices are equipped with a urethane resin blade-shaped wiper (contact pressure: 1.2 kgf / mm²) that wipes the ejection surface of the recording head. 2 The following was incorporated: The wiper penetration depth in the first wiping process was 1.3 mm, and the wiper penetration depth in the second and third wiping processes was 1.0 mm. In Comparative Example 4, an inkjet recording device equipped with two wipers with penetration depths of 1.3 mm and 1.0 mm was used. The time difference between the passage of the two wipers was 0.03 seconds. Immediately after peeling off the protective tape from the recording units of the types shown in Tables 3-1 and 3-2, the recording units were set in the carriage of the above recording device, the cleaning sequence described later was executed, and then the evaluation of each item described later was performed.

[0077] First, the first cleaning sequence was performed under the conditions shown in Tables 3-1 and 3-2. The details of the conditions are as follows. In the first cleaning sequence, a first wiping step was performed in which the discharge port surface was wiped with the bent side of the wiper, and then a second wiping step was performed in which the carriage height was changed and the discharge port surface was wiped with the edge of the wiper. In Examples 5 and 41, the protective tape was peeled off and the recording unit was immediately set in the recording device, and after recording five nozzle check patterns of "PIXUS TS5130S" or "G3370", the first cleaning sequence was executed. Condition 1: First wiping process twice → Second wiping process twice Condition 2: First wiping step once → Second wiping step once Condition 3: First wiping step 1 time → Second wiping step 2 times Condition 4: First wiping process twice → Second wiping process once Condition 5: First wiping step once → Second wiping step once → First wiping step once → Second wiping step once Condition 6: First wiping process 4 times Condition 7: Second wiping process, 4 times Condition 8: 1 time with 2 wipers

[0078] Next, under the conditions shown in Tables 3-1 and 3-2, a third wiping step was performed as the second cleaning sequence, in which the ejection port surface was wiped with the edge (or belly) of the wiper. In the examples where "Yes" is indicated in the "Heating of recording head" column in Tables 3-1 and 3-2, the temperature of the ink inside the recording head was heated to 60°C when performing the second cleaning sequence.

[0079] In this embodiment, the recording duty cycle of a solid image recorded under the condition that two ink droplets, each with a mass of 5.5 ng, are applied to a unit area of ​​1 / 600 inch × 1 / 600 inch is defined as 100%. The evaluation conditions are shown in Tables 3-1 and 3-2. In this invention, "AA," "A," and "B" are considered acceptable levels in the evaluation criteria for each item shown below, and "C" is considered an unacceptable level. The evaluation results are shown in Table 4.

[0080] TIFF0007830565000004.tif179170

[0081] TIFF0007830565000005.tif173170

[0082] (Discharge irregularities at the start of initial use) Each ink was concentrated by evaporating 10% of its original concentration to prepare concentrated inks. The prepared inks were placed in fluorine-coated containers and stored at 70°C for one month. The stored concentrated inks were used for evaluation to assess the ejection waviness under more stringent conditions. After storing the inks, they were injected into the ink reservoir of the recording unit, set in the recording device, and the nozzle surface was cleaned under the conditions shown in Tables 3-1 and 3-2. Subsequently, nozzle check patterns of the "PIXUS TS5130S" or "G3370" were recorded on glossy paper, coated paper, and plain paper, respectively. For glossy paper, "Photo Paper Gloss Gold GL-101" (Canon) was used. For coated paper, "High-Quality Specialty Paper HR-101" (Canon) was used. For plain paper, "PPC Paper CS-680" (Canon) was used. The three types of nozzle check patterns were visually observed, and the ejection waviness at the start of initial use was evaluated according to the evaluation criteria shown below. AA: No distortion was observed in the nozzle check pattern on any of the three types of recording media. A: Wrinkling occurred on glossy paper, but not on coated paper or plain paper. B: Wrinkling occurred on glossy paper and coated paper, but not on plain paper. C: Distortion was observed in all three types of recording media.

[0083] (Discharge irregularities after prolonged use) After performing the evaluation of "print waviness at the start of initial use" described above, nozzle check patterns of either the "PIXUS TS5130S" or "G3370" were recorded on 15,000 sheets of recording media (product name "High-Quality Dedicated Paper HR-101", manufactured by Canon). The nozzle check pattern recorded on the 15,000th sheet was visually observed, and print waviness after long-term use was evaluated according to the evaluation criteria shown below. A: No ejection irregularities were observed in the nozzle check pattern recorded on the 15,000th recording medium. C: The nozzle check pattern recorded on the 15,000th recording medium showed ejection irregularities.

[0084] TIFF0007830565000006.tif197170

[0085] Although the "discharge distortion at the start of initial use" in Examples 36 and 39 was ranked A, the discharge distortion was relatively suppressed compared to other A-ranked examples.

Claims

1. Using an inkjet recording device comprising: an aqueous ink containing a pigment and a resin; an ink storage section for storing the aqueous ink; a recording head incorporated in the ink storage section having a discharge port surface formed thereon for discharging the aqueous ink supplied from the ink storage section; and a wiping means for wiping the discharge port surface, wherein the discharge port surface is treated with a water-repellent coating, An inkjet recording method comprising the step of applying the aqueous ink ejected from the ejection port to a recording medium to record an image, A protective tape having an adhesive layer made of an adhesive, which is peeled off during use, is attached to the ejection port surface of the recording head. Furthermore, it has a first cleaning sequence that includes a first wiping step and a second wiping step, which are performed sequentially, in which the discharge port surface is wiped using a single blade-shaped wiper. The first wiping step is a step of bending the wiper and wiping the discharge port surface with the belly of the wiper, An inkjet recording method characterized in that the second wiping step is a step of wiping the discharge port surface with the edge portion of the wiper.

2. The inkjet recording method according to claim 1, wherein the first cleaning sequence is performed immediately after the protective tape is peeled off.

3. The inkjet recording method according to claim 1, wherein the first wiping step is performed only in the first cleaning sequence.

4. Furthermore, it includes a second cleaning sequence that is performed after the first cleaning sequence, The inkjet recording method according to claim 1, wherein the second cleaning sequence includes a third wiping step of wiping the discharge port surface with the edge of the wiper while heating the recording head.

5. The inkjet recording method according to claim 1, wherein the interval from the end of the first wiping step to the start of the second wiping step is 5 seconds or more and 15 seconds or less.

6. The inkjet recording method according to any one of claims 1 to 5, wherein the thickness of the wiper is 0.5 mm or more and 1.5 mm or less.

7. The inkjet recording method according to any one of claims 1 to 5, wherein the first wiping step and the second wiping step are each performed two or more times.

8. The inkjet recording method according to any one of claims 1 to 5, wherein the speed at which the discharge port surface is wiped using the wiper is 100 mm / s or more and 150 mm / s or less.

9. The inkjet recording method according to any one of claims 1 to 5, wherein the penetration amount of the wiper in the first wiping step is 1.0 mm or more and 1.8 mm or less, and the penetration amount of the wiper in the second wiping step is 0.3 mm or more and 1.0 mm or less.

10. The inkjet recording method according to any one of claims 1 to 5, wherein the pigment is carbon black.

11. The inkjet recording method according to any one of claims 1 to 5, wherein the content (by mass) of the pigment in the aqueous ink is 0.50% by mass or more and 10.00% by mass or less, based on the total mass of the ink.

12. The inkjet recording method according to any one of claims 1 to 5, wherein the content (by mass) of the resin in the aqueous ink is 0.10% by mass or more and 20.00% by mass or less, based on the total mass of the ink.

13. The inkjet recording method according to any one of claims 1 to 5, wherein the adhesive is a silicone-based adhesive or an acrylic-based adhesive.

14. The inkjet recording method according to any one of claims 1 to 5, wherein the adhesive is an acrylic adhesive.

15. The aforementioned acrylic adhesive contains a metal chelating crosslinking agent, The inkjet recording method according to claim 14, wherein the pH of the aqueous ink at 25°C is 8.6 or higher.

16. The inkjet recording method according to claim 11, wherein the pH of the aqueous ink at 25°C is 8.9 or more and 9.3 or less.

17. The inkjet recording method according to any one of claims 1 to 5, wherein the ink storage unit is replaced with another ink storage unit after the aqueous ink stored inside it has been consumed.

18. The inkjet recording method according to any one of claims 1 to 5, wherein the inkjet recording apparatus further comprises a second ink storage section having a larger capacity than the ink storage section, and a tube through which the aqueous ink flows between the second ink storage section and the ink storage section.

19. Using an inkjet recording device comprising: an aqueous ink containing a pigment and a resin; an ink storage section for storing the aqueous ink; a recording head incorporated in the ink storage section having a discharge port surface formed thereon for discharging the aqueous ink supplied from the ink storage section; and a wiping means for wiping the discharge port surface, wherein the discharge port surface is treated with a water-repellent coating, An inkjet recording apparatus used in an inkjet recording method that includes the step of applying the aqueous ink ejected from the ejection port to a recording medium to record an image, A protective tape having an adhesive layer made of an adhesive, which is peeled off during use, is attached to the ejection port surface of the recording head. The inkjet recording method further includes a first cleaning sequence comprising a first wiping step and a second wiping step, which are performed sequentially, in which the discharge port surface is wiped using a blade-shaped wiper. The first wiping step is a step of bending the wiper and wiping the discharge port surface with the belly of the wiper, An inkjet recording apparatus characterized in that the second wiping step is a step of wiping the discharge port surface with the edge of the wiper.

Images