JP2014168911A - Ink jet recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet recorder capable of stably discharging an ink composition by suppressing deterioration of a surface (a liquid repellent film) of a nozzle plate by wiping.SOLUTION: An ink jet recorder includes: multiple nozzles 21 discharging ink compositions; a nozzle plate 22 having multiple discharging ports 23 of nozzles 21; cleaning fluid wetting the ink compositions adhered on a surface of the nozzle plate 22; a wiping member 31 wiping a surface of the nozzle plate 22 and having liquid absorbency; and a moving mechanism varying a relative position of the nozzle plate 22 and the wiping member 31. The cleaning fluid contains at least one kind of a saccharide, an EO/PO copolymer, and a lubricant.

Description

  The present invention relates to an ink jet recording apparatus.

  Recording (printing) using the ink jet recording method is performed by ejecting and flying ink droplets and depositing them on a recording medium such as paper. In recent years, due to innovative advances in inkjet recording technology, inkjet recording apparatuses using an inkjet recording method have also been used in the field of high-definition image recording (image printing), which previously used photography and offset printing. Yes.

  In the ink jet recording apparatus, when moisture or other volatile components contained in the ejected ink evaporate, the viscosity of the ink increases (thickens). In recent ink jet recording apparatuses, in order to perform high-definition recording, the amount of ejected ink droplets is a very small amount of several picoliters, the diameter of the nozzle that ejects ink is small, and it is necessary to eject ink droplets. Energy is also getting smaller. Since the nozzle diameter is small and the discharge energy is also small, the ink that is attached to the nozzle and thickened easily causes clogging at the nozzle, and as a result, ink discharge failure may occur. Furthermore, fibers generated from a recording medium such as paper and cloth, paper dust, and surrounding dust may also adhere to the nozzle forming surface (nozzle plate surface), and similarly, normal ink ejection is hindered.

  In order to prevent or reduce the above-mentioned ink thickening and ejection failure due to foreign matter adhering to the nozzle plate surface, an ink jet recording apparatus provided with a wiper mechanism (nozzle recovery mechanism) has been proposed. For example, Patent Document 1 describes an ink jet recording apparatus provided with a cleaning mechanism using a wiping blade. Patent Document 1 discloses a technique for arranging fine particles on the surface of the wiping blade so as to reduce the coefficient of friction between the wiping blade and the head (nozzle plate surface) and protect the nozzle plate surface. Further, Patent Document 2 includes an application unit that applies a treatment liquid to a recording head or a wiping member as an inkjet recording apparatus that can simultaneously achieve low cost, high weather resistance, high durability, and high reliability. An ink jet recording apparatus that performs wiping when necessary, such as when it is determined that the (nozzle plate surface) is dry, is described.

JP 2006-142804 A JP 2009-101630 A

  However, the method using the wiping blade as in Patent Document 1 has a problem that the cleaning performance is poor when the uneven nozzle plate surface is cleaned. Specifically, when the surface of the nozzle plate has irregularities constituted by the nozzle plate and the nozzle plate cover, the ink scraped off by the wiping blade remains in the irregularities and cannot be sufficiently cleaned. In addition, in the case of an ink jet recording apparatus that performs recording using an ink composition containing an inorganic pigment, the inorganic pigment interposed between the wiping blade and the nozzle plate surface damages the liquid repellent film formed on the nozzle plate surface. There was a problem of scraping.

Similarly, in the case of an ink jet recording apparatus that performs recording using an ink composition containing an inorganic pigment, as disclosed in Patent Document 2, a coating means for applying a treatment liquid to a recording head (nozzle plate surface) or a wiping member is provided. Even if the apparatus is used, the inorganic pigment interposed between the wiping member and the nozzle plate surface damages and scrapes the liquid repellent film formed on the nozzle plate surface only by using the treatment liquid disclosed in Patent Document 2. There was a problem that there was a case.
An inorganic pigment is a component that can easily damage a liquid repellent film (such as a metal alkoxide molecular film having liquid repellency), as represented by carbon black and titanium dioxide. When the liquid repellent film is damaged, ink ejection becomes unstable, and the landing positions of ink droplets are disturbed.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following application examples or forms.

  Application Example 1 An ink jet recording apparatus according to this application example includes a plurality of nozzles for discharging an ink composition, a nozzle plate having discharge ports of the plurality of nozzles, and an ink composition attached to the surface of the nozzle plate. A cleaning liquid for wetting, a wiping member that wipes the surface of the nozzle plate and has a liquid absorbability, and a moving mechanism that varies a relative position of the nozzle plate and the wiping member. / PO copolymer, and at least one kind of lubricant.

  According to this application example, the ink composition attached to the nozzle plate is wetted by a cleaning liquid containing at least one of saccharide, EO / PO copolymer (ethylene oxide-propylene oxide copolymer), and lubricant (wax). Therefore, the damage that the wiping member gives to the surface of the nozzle plate can be further reduced. Specifically, since the cleaning liquid contains saccharides, it becomes possible to keep the surface of the wiping member and adhering matter softer, and by containing the EO / PO copolymer, the ink composition is contained inside the wiping member. Therefore, the friction between the wiping member and the surface of the nozzle plate can be further reduced by containing a lubricant. As a result, when the surface of the nozzle plate is wiped by the wiping member, damage to the surface of the nozzle plate by the wiping member itself or the ink composition interposed between the wiping member and the surface of the nozzle plate can be further reduced. it can. For example, even when the nozzle plate surface is provided with a liquid repellent film or the like, since the deterioration of the liquid repellent film is suppressed, the discharge of the ink composition can be maintained in a more stable state. .

  Application Example 2 In the ink jet recording apparatus according to the application example, it is preferable that the saccharide is a disaccharide or more polysaccharide.

  As in this application example, when the cleaning liquid is a polysaccharide having two or more saccharides, the moisture retaining property and flexibility of the wiping member can be further increased. As a result, when the surface of the nozzle plate is wiped by the wiping member, damage to the surface of the nozzle plate by the wiping member itself or the ink composition interposed between the wiping member and the surface of the nozzle plate can be further reduced. it can.

  Application Example 3 In the ink jet recording apparatus according to the application example, the EO / PO copolymer has 5 ≦ n ≦ 30 when the polymerization degree of EO is n and the polymerization degree of PO is m. It is preferable that 5 ≦ m ≦ 50 and n ≦ m.

  As in this application example, the EO / PO copolymer contained in the cleaning liquid has 5 ≦ n ≦ 30 when the polymerization degree of EO is n and the polymerization degree of PO is m, and 5 ≦ m ≦ When 50 and n ≦ m, the permeability of the ink composition to the wiping member can be further increased. As a result, when the surface of the nozzle plate is wiped by the wiping member, the damage that the ink composition interposed between the wiping member and the surface of the nozzle plate gives to the surface of the nozzle plate can be further reduced.

  Application Example 4 In the ink jet recording apparatus according to the application example, it is preferable that the lubricant is a polyolefin wax.

  As in this application example, when the lubricant contained in the cleaning liquid is a polyolefin wax, when the surface of the nozzle plate is wiped by the wiping member, the friction between the wiping member and the surface of the nozzle plate is further reduced. It becomes possible. As a result, when the surface of the nozzle plate is wiped by the wiping member, the damage that the wiping member itself gives to the surface of the nozzle plate can be further reduced.

  Application Example 5 In the ink jet recording apparatus according to the application example, it is preferable that the content of the saccharide or the EO / PO copolymer contained in the cleaning liquid is 5% by weight or more.

  As in this application example, when the content of the saccharide or EO / PO copolymer contained in the cleaning liquid is 5% by weight or more, the surface of the wiping member can be kept softer. Or it becomes easy to absorb an ink composition by the inside of a wiping member. As a result, when the surface of the nozzle plate is wiped by the wiping member, damage to the surface of the nozzle plate by the wiping member itself or the ink composition interposed between the wiping member and the nozzle plate surface is further reduced. Can do.

  Application Example 6 In the ink jet recording apparatus according to the application example, it is preferable that the content of the lubricant contained in the cleaning liquid is 1% by weight or more and 5% by weight or less.

  As in this application example, when the content of the lubricant contained in the cleaning liquid is 1% by weight or more and 5% by weight or less, the cleaning liquid contains at least one of saccharides and EO / PO copolymers. The friction between the wiping member and the surface of the nozzle plate can be further reduced while maintaining the above-described effects. As a result, when the surface of the nozzle plate is wiped by the wiping member, the damage that the wiping member itself gives to the surface of the nozzle plate can be further reduced.

  Application Example 7 In the ink jet recording apparatus according to the application example, a liquid repellent film is formed on a surface of the nozzle plate.

  According to this application example, since the liquid repellent film is formed on the surface of the nozzle plate, the ejection of the ink composition can be maintained in a more stable state. Further, according to this application example, even when the liquid repellent film is formed on the surface of the nozzle plate, the above-described effects can be effectively obtained. Specifically, when the surface of the nozzle plate is wiped by the wiping member, the liquid repellency in which the wiping member itself or an ink composition interposed between the wiping member and the surface of the nozzle plate is formed on the surface of the nozzle plate. Although the film may be damaged, in this application example, since the damage is further reduced, the liquid repellent film is more effectively maintained. As a result, the ejection of the ink composition can be maintained in a more stable state.

  Application Example 8 In the inkjet recording apparatus according to the application example, the ink composition contains an inorganic pigment.

  According to this application example, since the ink composition contains an inorganic pigment, it is possible to record an excellent image including, for example, black or white ink. Further, according to this application example, even when the ink composition contains an inorganic pigment, the above-described effects can be effectively obtained. Inorganic pigments can easily damage the surface of the nozzle plate and the liquid repellent film formed on the surface (such as molecular films of metal alkoxide having liquid repellency), as represented by carbon black and titanium dioxide. It is an ingredient that can be given. If the surface of the nozzle plate or the liquid repellent film formed on the surface of the nozzle plate is damaged around the ink discharge port, the ink discharge becomes unstable, and the landing position of the ink droplet is disturbed. In this application example, the ink composition containing the inorganic pigment is easily absorbed by the inside of the wiping member, and the surface of the wiping member is kept softer, so that the damage is further reduced. As a result, the ejection of the ink composition can be maintained in a more stable state.

1 is a perspective view showing an ink jet recording apparatus according to an embodiment. (A) Sectional drawing which shows a part of recording head, (b) The top view of the nozzle plate seen from the discharge port side. (A) The perspective view which shows a wiper unit, (b) The side sectional view which shows the structure of a wiper unit.

  DESCRIPTION OF EMBODIMENTS Embodiments embodying the present invention will be described below with reference to the drawings. The following is one embodiment of the present invention and does not limit the present invention. In the following drawings, the scale may be different from the actual scale for easy understanding.

FIG. 1 is a perspective view showing an ink jet recording apparatus 1 as an example according to the present embodiment.
First, the basic configuration of the inkjet recording apparatus 1 will be described.
<Inkjet recording apparatus>
The ink jet recording apparatus 1 is an apparatus that records characters, drawings, images, and the like by ejecting ink (ink composition) and attaching it to a recording medium by an ink jet recording head. As a method of the ink jet recording head, a piezo method is used as a preferable example. The piezo method is a method in which a pressure corresponding to a print information signal is applied to ink by a piezoelectric element (piezo element), and ink droplets are ejected and recorded.

  The method of the ink jet recording head is not limited to this, and other recording methods in which ink is ejected in the form of droplets to form dot groups on a recording medium may be used. For example, a strong electric field between a liquid ejection nozzle (hereinafter referred to as a nozzle) and an acceleration electrode placed in front of the nozzle causes ink to be continuously ejected from the nozzle in the form of droplets, and a printing information signal is given from the deflection electrode while the ink droplets fly. Recording method, or ejecting ink droplets in response to print information signals without deflecting (electrostatic suction method), applying pressure to the ink with a small pump, and mechanically vibrating the nozzle with a crystal resonator For example, a method of forcibly ejecting ink droplets, a method of heating and foaming ink with a microelectrode according to a print information signal, and ejecting and recording ink droplets (thermal jet method) may be used.

In FIG. 1, the ink jet recording apparatus 1 is installed on a substantially horizontal XY plane.
The ink jet recording apparatus 1 includes an ink jet recording head 20, a carriage 3, a carriage drive mechanism 4, a control board 5, an ink cartridge 6, a recording medium supply / discharge mechanism (not shown), a platen 8, a wiper unit 30, and the like. .

  The carriage 3 has a recording head 20 and an ink cartridge 6 mounted thereon, and scans on the surface of the recording medium 10 by the carriage driving mechanism 4 (reciprocating operation in the X direction in FIG. 1) (approximately -Z in FIG. 1). Direction), ink (ink composition) is ejected and recording is performed. The control board 5 performs drive control of the carriage drive mechanism 4 and the wiper unit 30, control of ink discharge, and control of supply and discharge of the recording medium 10. The ink cartridge 6 is divided into a plurality of storage portions and stores a plurality of ink compositions described later. The recording medium supply / discharge mechanism moves the recording medium 10 in a direction intersecting the scanning direction of the carriage 3 (Y direction in FIG. 1). The platen 8 mounts the recording medium 10 and defines the interval between the recording head 20 and the recording medium 10.

<Recording head>
2A is a cross-sectional view showing a part of the recording head 20, and FIG. 2B is a plan view of the nozzle plate 22 as viewed from the ejection port 23 side. Fig.2 (a) has shown the AA cross section in FIG.2 (b).
The recording head 20 has a nozzle plate 22 provided with a plurality of nozzles 21 for discharging an ink composition, and the nozzle plate 22 has nozzle openings (discharge ports 23). A liquid repellent film 24 is formed on the surface of the nozzle plate 22.
The nozzle plate 22 is provided with a nozzle plate cover 25 that covers at least a part of the nozzle plate 22. The nozzle plate cover 25 serves to fix the nozzle chip 26 in the recording head 20 formed by a combination of a plurality of nozzle chips 26, or the recording medium 10 is lifted and the recording medium 10 comes into direct contact with the nozzle 21. It is provided for the role of preventing the situation. The nozzle plate cover 25 covers at least a part of the nozzle plate 22 so as to protrude from the nozzle plate 22 when viewed from the side. Since the ink composition may remain in the stepped portion with respect to the protruding portion or in the vicinity of the ejection port 23, the ink composition is removed by a wiping member 31 (FIGS. 3A and 3B) provided in the wiper unit 30 described later.

<Liquid repellent film>
The liquid repellent film 24 is not particularly limited as long as it is a liquid repellent film. The liquid repellent film 24 can be formed, for example, by forming a molecular film of metal alkoxide having liquid repellency, and then performing a drying process, an annealing process, and the like. Any metal alkoxide molecular film may be used as long as it has liquid repellency, but a metal alkoxide monomolecular film having a long-chain polymer group containing fluorine (long-chain RF group), or a liquid-repellent group ( For example, a monomolecular film of a metal acid salt having a long-chain polymer group containing fluorine) is desirable. Although it does not specifically limit as a metal alkoxide, For example, silicon, titanium, aluminum, and zirconium are generally used as the metal seed | species. Examples of the long chain RF group include a perfluoroalkyl chain and a perfluoropolyether chain. Examples of the alkoxysilane having a long chain RF group include a silane coupling agent having a long chain RF group. Further, as the liquid repellent film 24, for example, a SCA (Silane Coupling Agent) film or a film described in Japanese Patent No. 4424954 can be used.

  The liquid repellent film 24 may be formed by forming a conductive film on the surface of the nozzle plate 22 and forming the conductive film on the conductive film. However, by first polymerizing a silicon material, a base film (PPSi (Plasma Polymerized Silicone) is formed. ) Film) may be formed and formed on this base film. Through this base film, the silicon material of the nozzle plate 22 and the liquid repellent film 24 can be blended.

  The liquid repellent film 24 preferably has a thickness of 1 nm to 30 nm, more preferably has a thickness of 1 nm to 20 nm, and still more preferably has a thickness of 1 nm to 15 nm. With such a thickness range, the nozzle plate 22 tends to be more excellent in liquid repellency, the film deterioration is relatively slow, and the liquid repellency can be maintained for a longer period. Moreover, it is excellent in terms of cost and ease of film formation.

<Wiper unit>
FIG. 3A is a perspective view showing the wiper unit 30, and FIG. 3B is a side sectional view showing the configuration of the wiper unit 30.
The wiper unit 30 includes a wiping member 31, a feed roller 32, a material removal roller 33, a pressing roller 34, a housing 35, a wiper unit driving mechanism, and the like.

  Inside the housing 35, a pair of material supply roller 32 and material removal roller 33 having an axis extending substantially horizontally in the X direction, which is the longitudinal direction of the housing 35, is the Y direction in which the housing 35 is short. Is housed at a distance. An absorbing member (wiping member 31) for wiping off ink remaining on the surface of the nozzle plate 22 is hung between the pair of the material supply roller 32 and the material removal roller 33. The feed roller 32 feeds out the wound unused wiping member 31, and the material removal roller 33 winds up the used wiping member 31 unwound from the feed roller 32 and used for wiping.

  A pressing roller 34 having an axis substantially parallel to the supply roller 32 and the material removal roller 33 is exposed from the casing 35 in the Z direction at the top of the casing 35. The wiping member 31 fed out from the feed roller 32 is wound around the pressing roller 34 and wound around the material removal roller 33 after use.

  The wiper unit drive mechanism (not shown) has a function of rotationally driving the material supply roller 32 and the material removal roller 33 as shown by the arrows shown in FIG. 3B, and a wiping portion of the wiping member 31 supported by the pressing roller 34. It has a function of moving (up and down) W to the ink wiping position (height) of the nozzle plate 22, and these functions are controlled by the control board 5.

<Wiping member>
The wiping member 31 has liquid absorptivity. As a result, the wiped pigment particles are redispersed and easily move from the surface of the wiping member 31 to the inside, and the pigment particles are less likely to remain on the surface of the wiping member 31, so that the liquid repellent film 24 is damaged by the pigment particles. It is suppressed.

  The wiping member 31 is not particularly limited as long as it can absorb the inorganic pigment-containing ink composition and the cleaning liquid adhering to the nozzle outlet 23 and the nozzle plate 22. Although it does not specifically limit as the wiping member 31, For example, a cloth, sponge, a pulp, etc. are mentioned. Among these, a fabric is preferable. If it is a fabric, it is easy to bend and it will be easier to wipe off the adhered ink. The fabric is not particularly limited, and examples thereof include those made of cupra, polyester, polyethylene, polypropylene, lyocell, rayon, and the like. In particular, it is preferable that the material of the wiping member 31 is a non-woven fabric (polyester) or cupra because fuzzing is small and it is difficult for dots to be lost due to ink suction.

The thickness of the wiping member 31 is preferably 0.1 mm or more and 3 mm or less. When the thickness is 0.1 mm or more, it becomes easier to hold and absorb the cleaning liquid and the deposits. When the thickness is 3 mm or less, the wiping member 31 is compact, the wiper unit 30 can be downsized, and the wiper unit 30 can be driven more easily.
The surface density of the wiping member 31, 0.005 g / cm ² or more 0.15 g / cm ² or less. More preferably, the 0.02 g / cm ² or more 0.13 g / cm ² or less. By being in the above-mentioned range, it becomes easier to hold and absorb the cleaning liquid and the deposits. Furthermore, it is preferable to use a non-woven fabric for which the surface density and thickness can be easily designed for the wiping member 31 in order to retain the cleaning liquid.

<Cleaning liquid>
The cleaning liquid contains a penetrating agent and a humectant. As a result, the wiping member 31 becomes softer and the pigment particles are more easily absorbed in the wiping member 31. Details of the cleaning liquid will be described in Embodiment 1 described later.
The method of using the cleaning liquid is not particularly limited, but may be a method of directly applying to the nozzle plate 22 or a method of preliminarily including the cleaning liquid in the wiping member 31 and maintaining the state with a moisturizing agent. Alternatively, a method may be used in which a cleaning liquid is applied to and included in the wiping member 31 before the wiping operation. Preferably, a method of preliminarily containing the cleaning liquid in the wiping member 31 and maintaining the state with a moisturizer or the like, or a method of adding the cleaning liquid to the wiping member 31 and including it before each wiping operation is preferable.

<Movement mechanism>
The moving mechanism moves at least one of the wiping member 31 and the recording head 20 relative to the other, wipes the surface of the nozzle plate 22 by the wiping member 31, and adheres to the surface of the nozzle plate 22. A cleaning operation is performed to remove water. Specifically, the moving mechanism is constituted by a wiper unit driving mechanism, for example, and is controlled by the control board 5.

The wiper unit drive mechanism has a pressing function of pressing the wiping member 31 against the surface of the nozzle plate 22 by relatively moving the wiping member 31 and the nozzle plate 22. A preferable pressing load is 50 gf or more and 500 gf or less, and more preferably 75 gf or more and 300 gf or less. The pressing function may be configured to press the wiping member 31 against the nozzle plate 22 or may be configured to move the recording head 20 and press it against the wiping member 31. When the pressing force is 50 gf or more, the ink wiping property is excellent. Furthermore, even when there is a step formed between the nozzle plate 22 and the nozzle plate cover 25, it is excellent in preventing or removing ink adhering to the gap. Further, when the pressing force is 500 gf or less, the storage stability of the liquid repellent film 24 is further improved.
The load referred to here is the sum of the loads applied to the nozzle plate 22 from the entire drive mechanism.

Further, the moving mechanism may be a mechanism that relatively moves the wiping member 31 and the recording head 20 after pressing at a speed of 1 cm / s or more and 10 cm / s or less (in the + Y direction, the −Y direction, or the ± Y direction). preferable. By moving within this speed range, the cleaning property and the storage stability of the liquid repellent film 24 are further improved.
The Y-direction moving mechanism may be provided in the wiper unit driving mechanism, or may be configured to move relative to the wiping member 31 by moving the recording head 20.

  Although the press roller 34 mentioned above is not specifically limited, For example, what was coat | covered with the elastic member is preferable. The Shore A hardness of the elastic member is preferably 10 or more and 60 or less, and more preferably 10 or more and 50 or less. Thereby, the pressing roller 34 and the wiping member 31 are bent at the time of pressing, and the wiping member 31 can be pushed into the concave portion with respect to the uneven surface of the nozzle plate 22. In particular, when there is the nozzle plate cover 25, the wiping member 31 can be pushed into the corner (step portion) between the nozzle plate 22 and the nozzle plate cover 25 protruding from the nozzle plate 22 to deposit ink. Can be suppressed. Therefore, the cleaning property is further improved.

<Ink composition>
Next, the ink composition will be described. The ink composition includes an ink composition containing an inorganic pigment (hereinafter referred to as an inorganic pigment-containing ink composition), an ink composition containing a color material other than the inorganic pigment (hereinafter referred to as an inorganic pigment-free ink composition), and the like. It is composed of a color material (inorganic pigment, organic pigment, dye, etc.), a solvent (water, organic solvent, etc.), a resin, a surfactant, and the like.

<Color material>
The inorganic pigment-containing ink composition contains an inorganic pigment as a coloring material in a range of 1.0 wt% to 20.0 wt%. In particular, when the inorganic pigment-containing ink composition is a white ink composition, the inorganic pigment concentration is preferably 5% by weight or more.
Further, the inorganic pigment-free ink composition may contain a color material selected from pigments and dyes other than inorganic pigments.

<Pigment>
The inorganic pigment contained in the inorganic pigment-containing ink composition preferably has an average particle diameter of 20 nm to 250 nm, more preferably 20 nm to 200 nm.
Examples of inorganic pigments include simple metals such as carbon black, gold, silver, copper, aluminum, nickel, and zinc, and cerium oxide, chromium oxide, aluminum oxide, zinc oxide, magnesium oxide, silicon oxide, tin oxide, and oxide. Oxides such as zirconium, iron oxide and titanium oxide, sulfates such as calcium sulfate, barium sulfate and aluminum sulfate, silicates such as calcium silicate and magnesium silicate, and boron nitride and titanium nitride Examples thereof include nitrides, carbides such as silicon carbide, titanium carbide, boron carbide, tungsten carbide, and zirconium carbide, and borides such as zirconium boride and titanium boride.

  Examples of white inorganic pigments include alkaline earth metal sulfates such as barium sulfate, alkaline earth metal carbonates such as calcium carbonate, silicas such as finely divided silicate and synthetic silicate, calcium silicate, alumina, and alumina. Examples include hydrates, metal compounds such as titanium oxide and zinc oxide, and talc and clay. In particular, titanium oxide is known as a white pigment having favorable hiding properties, coloring properties, and dispersed particle sizes.

  The organic pigment is not particularly limited. Examples include perylene pigments, diketopyrrolopyrrole pigments, perinone pigments, quinophthalone pigments, anthraquinone pigments, thioindigo pigments, benzimidazolone pigments, isoindolinone pigments, azomethine pigments, and azo pigments. It is done. Specific examples of the organic pigment include the following.

  Examples of pigments used for cyan ink include C.I. I. Pigment Blue 1, 2, 3, 15, 15: 1, 15: 2, 15: 3, 15: 4, 15: 6, 15:34, 16, 18, 22, 60, 65, 66, C.I. I. Bat Blue 4, 60, etc. are mentioned. Among them, C.I. I. At least one of pigment blue 15: 3 and 15: 4 is preferable.

  Examples of pigments used in magenta ink include C.I. I. Pigment Red 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 14, 15, 16, 17, 18, 19, 21, 22, 23, 30, 31, 32, 37, 38, 40, 41, 42, 48 (Ca), 48 (Mn), 57 (Ca), 57: 1, 88, 112, 114, 122, 123, 144, 146, 149, 150, 166, 168 170, 171, 175, 176, 177, 178, 179, 184, 185, 187, 202, 209, 219, 224, 245, 254, 264, C.I. I. Pigment violet 19, 23, 32, 33, 36, 38, 43, 50 and the like. Among them, C.I. I. Pigment red 122, C.I. I. Pigment red 202, and C.I. I. One or more selected from the group consisting of Pigment Violet 19 is preferred.

Examples of pigments used in yellow ink include C.I. I. Pigment Yellow 1, 2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 14, 16, 17, 24, 34, 35, 37, 53, 55, 65, 73, 74, 75, 81, 83, 93, 94, 95, 97, 98, 99, 108, 109, 110, 113, 114, 117, 120, 124, 128, 129, 133, 138, 139, 147, 151, 153, 154, 155, 167, 172, 180, 185, 213 and the like. Among them, C.I. I. One or more selected from the group consisting of CI Pigment Yellow 74, 155, and 213 are preferred.
In addition, conventionally well-known things are mentioned as a pigment used for inks of colors other than the above, such as green ink and orange ink.

The average particle diameter of the pigments other than the inorganic pigment is preferably 250 nm or less in order to prevent clogging at the nozzle (discharge port 23) and to further improve the discharge stability.
In addition, the average particle diameter in this specification is based on a volume. As a measuring method, for example, it can be measured by a particle size distribution measuring apparatus using a laser diffraction scattering method as a measurement principle. Examples of the particle size distribution measuring apparatus include a particle size distribution meter (for example, Microtrac UPA manufactured by Nikkiso Co., Ltd.) having a dynamic light scattering method as a measurement principle.

<Dye>
A dye can be used as the coloring material. The dye is not particularly limited, and acid dyes, direct dyes, reactive dyes, and basic dyes can be used.
The content of the color material is preferably 0.4 to 12% by weight and more preferably 2 to 5% by weight with respect to the total mass (100% by weight) of the ink composition.

<Resin>
Examples of the resin include a resin dispersant, a resin emulsion, and a wax (lubricant). Among these, emulsions are preferred because they have good adhesion and abrasion resistance.

<Resin dispersant>
When the ink composition contains the pigment, the ink composition may contain a resin dispersant so that the pigment can be stably dispersed and held in water. When the ink composition contains a pigment (resin-dispersed pigment) dispersed using a resin dispersant such as a water-soluble resin or a water-dispersible resin, the recording medium when the ink composition adheres to the recording medium 10 The adhesion between at least one of the ink 10 and the ink composition and between the solidified materials in the ink composition can be improved. Among the resin dispersants, a water-soluble resin is preferable because of excellent dispersion stability.

<Resin emulsion>
The ink composition preferably contains a resin emulsion. By forming a resin film, the resin emulsion exhibits an effect of sufficiently fixing the ink composition on the recording medium 10 and improving the abrasion resistance of the image. The recorded matter recorded using the ink composition containing the resin emulsion due to the above effects is excellent in adhesion and abrasion resistance, particularly on the fabric, the ink non-absorbing or low-absorbing recording medium 10. Become. On the other hand, solidification of the inorganic pigment tends to be promoted, but the present invention can satisfactorily prevent problems caused by solidification.

  The resin emulsion that functions as a binder is preferably contained in the ink composition in an emulsion state. By including a resin functioning as a binder in the ink composition in an emulsion state, it is easy to adjust the viscosity of the ink composition to an appropriate range in the ink jet recording system, and the storage stability and ejection stability of the ink composition. Can be made excellent.

  The resin emulsion is not particularly limited. For example, (meth) acrylic acid, (meth) acrylic ester, acrylonitrile, cyanoacrylate, acrylamide, olefin, styrene, vinyl acetate, vinyl chloride, vinyl alcohol, vinyl ether, vinyl pyrrolidone, Examples thereof include homopolymers or copolymers of vinylpyridine, vinylcarbazole, vinylimidazole, and vinylidene chloride, fluororesins, and natural resins. Among them, at least one of (meth) acrylic resin and styrene- (meth) acrylic acid copolymer resin is preferable, and at least one of acrylic resin and styrene-acrylic acid copolymer resin is more preferable, styrene. -Acrylic acid copolymer resin is more preferable. The above copolymer may be in any form of a random copolymer, a block copolymer, an alternating copolymer, and a graft copolymer.

  The resin emulsion may be a commercially available product or may be prepared using an emulsion polymerization method or the like as follows. As a method for obtaining the resin in the ink composition in an emulsion state, the above-mentioned water-soluble resin monomer is emulsion-polymerized in water containing a polymerization catalyst and an emulsifier. The polymerization initiator, the emulsifier, and the molecular weight modifier used in the emulsion polymerization can be used according to a conventionally known method.

  The average particle size of the resin emulsion is preferably in the range of 5 nm to 400 nm, and more preferably in the range of 20 nm to 300 nm, in order to further improve the storage stability and ejection stability of the ink.

  A resin emulsion may be used individually by 1 type, and may be used in combination of 2 or more type. Among the resins, the content of the resin emulsion is preferably in the range of 0.5 to 15% by weight with respect to the total mass (100% by weight) of the ink composition. When the content is within the above range, the solid content concentration can be lowered, so that the discharge stability can be further improved.

<Wax>
The ink composition may contain a wax (lubricant). By including the wax in the ink composition, the ink composition is more excellent in fixability on the non-ink-absorbing and low-absorbing recording medium 10. Among the waxes, an emulsion or suspension type is more preferable. Examples of the wax include, but are not limited to, polyethylene wax, paraffin wax, and polypropylene wax. Among these, polyethylene wax is preferable.

When the ink composition contains polyethylene wax, the ink can have excellent abrasion resistance.
The average particle diameter of the polyethylene wax is preferably in the range of 5 nm to 400 nm, and more preferably in the range of 50 nm to 200 nm, in order to further improve the storage stability and ejection stability of the ink.

  The polyethylene wax content (in terms of solid content) is preferably in the range of 0.1 to 3% by weight and more preferably in the range of 0.3 to 3% by weight with respect to the total mass (100% by weight) of the ink composition. The range of 0.3 to 1.5% by weight is more preferable. When the content is in the above range, the ink composition can be solidified and fixed satisfactorily on the recording medium 10, and the storage stability and ejection stability of the ink are further improved.

<Antifoaming agent>
The ink composition preferably contains an antifoaming agent. More specifically, it is preferable that at least one of the cleaning liquid included in the ink composition or the wiping member 31 includes an antifoaming agent. When the ink composition contains an antifoaming agent, foaming can be prevented, and as a result, a problem that bubbles enter the nozzle 21 can be prevented.

  Examples of the antifoaming agent include, but are not limited to, a silicon-based antifoaming agent, a polyether-based antifoaming agent, a fatty acid ester-based antifoaming agent, and an acetylene glycol-based antifoaming agent. Among these, a silicon-based antifoaming agent and an acetylene glycol-based antifoaming agent are preferable because they are excellent in ability to appropriately maintain surface tension and interfacial tension and hardly generate bubbles. Moreover, as for the HLB value based on the Griffin method of an antifoamer, 5 or less is more preferable.

<Surfactant>
The ink composition may contain a surfactant (excluding those listed as the antifoaming agent. That is, the ink composition is limited to those having an HLB value of more than 5 by the Griffin method). Although it does not specifically limit as surfactant, For example, a nonionic surfactant is mentioned. The nonionic surfactant has an action of spreading the ink uniformly on the recording medium 10. Therefore, when ink jet recording is performed using an ink containing a nonionic surfactant, a high-definition image with almost no bleeding can be obtained. Such nonionic surfactants are not particularly limited, but include, for example, silicon-based, polyoxyethylene alkyl ether-based, polyoxypropylene alkyl ether-based, polycyclic phenyl ether-based, sorbitan derivatives, and fluorine-based surfactants. Examples thereof include silicon-based surfactants.

The silicon-based surfactant is excellent in the effect of spreading the ink uniformly so as not to cause bleeding on the recording medium 10 as compared with other nonionic surfactants.
Although it does not specifically limit as a silicon-type surfactant, A polysiloxane type compound is mentioned preferably. Although it does not specifically limit as a polysiloxane type compound, For example, polyether modified organosiloxane is mentioned. Although it does not specifically limit as a commercial item of polyether modified organosiloxane, For example, BYK-306, BYK-307, BYK-333, BYK-341, BYK-345, BYK-346, BYK-348, BYK-349 ( (Trade name, manufactured by BYK), KF-351A, KF-352A, KF-353, KF-354L, KF-355A, KF-615A, KF-945, KF-640, KF-642, KF-643, KF -6020, X-22-4515, KF-6011, KF-6012, KF-6015, KF-6017 (above trade names, manufactured by Shin-Etsu Chemical Co., Ltd.) and the like.

  Surfactant may be used individually by 1 type, and 2 or more types may be mixed and used for it. The content of the surfactant is such that the storage stability and ejection stability of the ink are further improved, so that the content of the surfactant is 0.1 wt% or more and 3 wt% or less with respect to the total mass of the ink (100 wt%) A range is preferable.

<Water>
The ink composition may contain water. In particular, when the ink composition is a water-based ink, water is a main medium of the ink, and is a component that evaporates and scatters when the recording medium 10 is heated in ink jet recording.

Examples of water include water from which ionic impurities have been removed as much as possible, such as pure water such as ion exchange water, ultrafiltration water, reverse osmosis water, and distilled water, and ultrapure water. Further, when water sterilized by ultraviolet irradiation or addition of hydrogen peroxide is used, generation of mold and bacteria can be prevented when the pigment dispersion and ink using the same are stored for a long period of time.
The water content is not particularly limited, and may be appropriately determined as necessary.

<Organic solvent>
The ink composition may contain a volatile water-soluble organic solvent. Although it does not specifically limit as an organic solvent, For example, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, 1,3-propanediol, 1,2-butanediol, 1,2-pentanediol, 1 , 2-hexanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, diethylene glycol mono-n-propyl ether, ethylene glycol mono-iso-propyl ether, diethylene glycol mono-iso-propyl Ether, ethylene glycol mono-n-butyl ether, ethylene glycol mono-t-butyl ether, diethylene glycol mono-n-butyl ether, triethylene glycol mono-n-butyl ether Diethylene glycol mono-t-butyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol mono-t-butyl ether, propylene glycol mono-n-propyl ether, propylene glycol mono-iso-propyl ether, propylene glycol mono-n- Butyl ether, dipropylene glycol mono-n-butyl ether, dipropylene glycol mono-n-propyl ether, dipropylene glycol mono-iso-propyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, diethylene glycol ethyl methyl ether, diethylene glycol butyl methyl Ete , Triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, dipropylene glycol dimethyl ether, dipropylene glycol diethyl ether, tripropylene glycol dimethyl ether, methanol, ethanol, n-propyl alcohol, iso-propyl alcohol, n-butanol, 2-butanol, tert Alcohols or glycols such as butanol, iso-butanol, n-pentanol, 2-pentanol, 3-pentanol, and tert-pentanol, N, N-dimethylformamide, N, N-dimethylacetamide, 2 -Pyrrolidone, N-methyl-2-pyrrolidone, 2-oxazolidone, 1,3-dimethyl-2-imidazolidinone, dimethyl sulfoxide, Examples include ruphoran and 1,1,3,3-tetramethylurea.
An organic solvent may be used individually by 1 type, and may be used in combination of 2 or more type. The content of the organic solvent is not particularly limited and may be appropriately determined as necessary.

<PH adjuster>
The ink composition may contain a pH adjuster. Examples of the pH adjuster include inorganic alkalis such as sodium hydroxide and potassium hydroxide, ammonia, diethanolamine, triethanolamine, triisopropanolamine, morpholine, potassium dihydrogen phosphate, and disodium hydrogen phosphate.
A pH adjuster may be used individually by 1 type, and may be used in combination of 2 or more type. The content of the pH adjuster is not particularly limited, and may be appropriately determined as necessary.

<Other ingredients>
The ink composition may further contain a preservative / antifungal agent, a rust inhibitor, a chelating agent, and the like in addition to the above components.

<Method for producing ink composition>
The ink composition can be obtained by mixing the above-described components (materials) in an arbitrary order, performing filtration or the like as necessary, and removing impurities. Here, it is preferable to prepare the pigment in a state of being uniformly dispersed in a solvent before mixing, because the handling becomes simple.

A specific embodiment of the ink jet recording apparatus 1 having the basic configuration described above will be described below.
(Embodiment 1)
As described above, the ink jet recording apparatus 1 includes a plurality of nozzles 21 for discharging an ink composition, a nozzle plate 22 having discharge ports 23 of the plurality of nozzles 21, and a wiping member that contains a cleaning liquid and wipes the surface of the nozzle plate 22. 31 and a moving mechanism for changing the relative position of the nozzle plate 22 and the wiping member 31. The cleaning liquid contains at least one of a saccharide, an EO / PO copolymer, and a lubricant.

Here, details of the cleaning liquid will be described.
<Sugar>
Examples of the saccharide include glucose, ribose, mannitol, mannose, fructose, ribose, xylose, arabinose, galactose, aldonic acid, glucitol (sorbitol), maltose, cellobiose, lactose, sucrose, trehalose, maltotriose, and the like. In addition, monosaccharides, disaccharides or more (oligosaccharides (including trisaccharides and tetrasaccharides) and polysaccharides) may be contained. Here, the polysaccharide means a saccharide in a broad sense, and is used to mean a substance that exists widely in nature, such as alginic acid, α-cyclodextrin, and cellulose.

  The saccharide is preferably a disaccharide or more, more preferably a monosaccharide or a disaccharide or more. The proportion of monosaccharides is preferably 5% by mass or more and less than 50% by mass, and more preferably 20% by mass or more and 45% by mass or less with respect to the total sugar contained in the ink. Thereby, the moisture retention of a washing | cleaning liquid and the wiping off of an deposit | attachment improve. In addition, when adding monosaccharide and 2 or more sugars to the ink, the monosaccharide and 2 or more sugars may be added separately, or a mixed sugar containing two (eg, syrup) may be added. Good.

<EO / PO copolymer>
An EO / PO copolymer (ethylene oxide-propylene oxide copolymer) that can be contained in the cleaning liquid is represented by the chemical formula (1). Here, EO (ethylene oxide) is represented by chemical formula (2), and PO (propylene oxide) is represented by chemical formula (3).

  As shown in chemical formula (1), when the polymerization degree of EO is n (n1, n2) and the polymerization degree of PO is m, 5 ≦ n ≦ 30, 5 ≦ m ≦ 50, and It is preferable that n ≦ m. Preferred examples include, but are not limited to, polyethylene glycol polypropylene glycol alkyl ether.

<Lubricant>
The lubricant that can be contained in the cleaning liquid is preferably a polyolefin wax. Preferred examples include polyethylene wax AQ515 (manufactured by Big Chemie Japan). The lubricant preferably has a particle size of a certain level or more. For example, a polyethylene wax having an average particle diameter of 100 nm or more is preferable, and a range of 200 nm to 400 nm is more preferable.
The lubricant is not limited to a hydrocarbon-based lubricant such as polyolefin wax, and may be a fatty acid-based, aliphatic amide-based, metal soap-based, ester-based lubricant or the like.

  Saccharides and EO / PO copolymers may be used alone or in combination of two or more. The content of saccharide or EO / PO copolymer contained in the cleaning liquid is preferably 5% by weight or more, and more preferably 10% by weight or more. The upper limit of the saccharide content is not particularly limited, but is preferably 80% by mass or less. This is because if a large amount of saccharide is contained, stickiness or the like may occur, and ejection may become unstable after cleaning. Moreover, it is preferable that the content rate of the lubricant contained in a washing | cleaning liquid is 1 to 5 weight%.

<Other specifications of cleaning liquid>
The surface tension of the cleaning liquid is preferably 45 mN / m or less. When the surface tension is low, the permeability of the inorganic pigment to the absorbing member becomes good and the wiping property is improved. As a method for measuring the surface tension, a commonly used surface tension meter (for example, surface tension meter CBVP-Z manufactured by Kyowa Interface Science Co., Ltd.) is used and measured at a liquid temperature of 25 ° C. by the Wilhelmy method. A method can be exemplified.

  When the cleaning liquid is contained in the absorbent member, the content thereof is preferably 10% by weight to 200% by weight with respect to 100% by weight of the absorbent member (wiping member 31), and 30% by weight to 100% by weight. More preferred. By being 10% by weight or more, the inorganic pigment ink can easily penetrate into the absorbing member, and the liquid repellent film 24 can be further prevented from being damaged. Further, when the content is 200% by weight or less, the remaining of the cleaning liquid in the nozzle plate 22 can be further suppressed, and dot omission due to the bubble entering the nozzle together with the cleaning liquid, or the cleaning liquid itself entering the nozzle. Dot missing can be further suppressed.

  In addition, although it does not specifically limit as an additive (component) which can be contained in a washing | cleaning liquid, For example, resin, an antifoamer, surfactant, water, an organic solvent, a pH adjuster, other moisturizing agents etc. are mentioned. . Each of the above components may be used alone or in combination of two or more.

When the cleaning liquid contains an antifoaming agent, it is possible to effectively prevent the cleaning liquid remaining on the nozzle plate 22 after the cleaning process from foaming.
As the pH adjuster, a pH adjuster contained in the ink composition described above, such as triethanolamine, can be used. By including a pH adjuster in the cleaning liquid, it is possible to prevent the ink composition in contact with the cleaning liquid from shifting to the acidic side and to suppress aggregation of the pigment. As a result, the storage stability of the ink composition is further maintained.

  In addition, the saccharide and EO / PO copolymer that can be contained in the cleaning liquid also have a function as a humectant, but the cleaning liquid may contain other humectants. Any other humectant can be used without particular limitation as long as it is generally usable for ink. The other moisturizing agent is not particularly limited, and a high boiling point moisturizing agent having a boiling point under 1 atm of preferably 180 ° C. or higher, more preferably 200 ° C. or higher can be used. When the boiling point is within the above range, the volatile component in the cleaning liquid can be prevented from volatilizing, and the inorganic pigment-containing ink composition in contact with the cleaning liquid can be reliably wetted and wiped off effectively. Other humectants may be used alone or in combination of two or more.

  Although it does not specifically limit as a high boiling point moisturizer, For example, ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, pentamethylene glycol, trimethylene glycol, 2-butene-1,4-diol, 2-ethyl-1,3 -Hexanediol, 2-methyl-2,4-pentanediol, tripropylene glycol, polyethylene glycol, polypropylene glycol, 1,3-propylene glycol, isopropylene glycol, isobutylene glycol, glycerin, mesoerythritol, pentaerythritol, etc. It is done.

As described above, according to the ink jet recording apparatus according to the present embodiment, the following effects can be obtained.
When the surface of the nozzle plate 22 is wiped, the deposit and the wiping member 31 are wetted (or wetted) by a cleaning liquid containing at least one of sugar, EO / PO copolymer, and lubricant (wax). Therefore, the damage that the wiping member 31 gives to the surface of the nozzle plate 22 can be further reduced. Specifically, by containing saccharide, the surface of the wiping member 31 can be kept softer, and by containing the EO / PO copolymer, the ink composition is absorbed by the inside of the wiping member 31. It becomes easy and the friction between the wiping member 31 and the surface of the nozzle plate 22 can be further reduced by containing the lubricant. As a result, when the surface of the nozzle plate 22 is wiped by the wiping member 31, the wiping member 31 itself or the ink composition interposed between the wiping member 31 and the surface of the nozzle plate 22 damages the surface of the nozzle plate 22. Can be further reduced. In the case where the surface of the nozzle plate 22 is provided with the liquid repellent film 24 or the like, the deterioration of the liquid repellent film 24 is suppressed, so that the ejection of the ink composition can be maintained in a more stable state.

  In addition, when a polysaccharide having two or more saccharides is used as the saccharide contained in the cleaning liquid, the moisture retaining property and flexibility of the wiping member 31 can be further improved. As a result, when the surface of the nozzle plate 22 is wiped by the wiping member 31, the wiping member 31 itself or the ink composition interposed between the wiping member 31 and the surface of the nozzle plate 22 damages the surface of the nozzle plate 22. Can be further reduced.

  In the EO / PO copolymer, when EO polymerization degree is n and PO polymerization degree is m, 5 ≦ n ≦ 30, 5 ≦ m ≦ 50, and n ≦ m. When a certain EO / PO copolymer is employed, the permeability of the ink composition to the wiping member 31 can be further increased. As a result, when the surface of the nozzle plate 22 is wiped by the wiping member 31, damage to the surface of the nozzle plate 22 by the ink composition interposed between the wiping member 31 and the surface of the nozzle plate 22 is further reduced. Can do.

  Further, when the lubricant is a polyolefin wax, when the surface of the nozzle plate 22 is wiped by the wiping member 31, the friction between the wiping member 31 and the surface of the nozzle plate 22 can be further reduced. As a result, when the surface of the nozzle plate 22 is wiped by the wiping member 31, damage to the surface of the nozzle plate 22 by the wiping member 31 itself can be further reduced.

  Preferably, the surface of the wiping member 31 can be kept softer by setting the content of the saccharide or EO / PO copolymer contained in the cleaning liquid to 5% by weight or more, or the ink composition. Is more easily absorbed by the inside of the wiping member 31. As a result, when the surface of the nozzle plate 22 is wiped by the wiping member 31, the wiping member 31 itself or an ink composition interposed between the wiping member 31 and the surface of the nozzle plate 22 is applied to the surface of the nozzle plate 22. Damage can be further reduced.

  Preferably, the content of the lubricant contained in the cleaning liquid contained in the wiping member 31 is 1% by weight or more and 5% by weight or less, so that the cleaning liquid contains at least one kind of saccharide and EO / PO copolymer. In this case, it is possible to further reduce the friction between the wiping member 31 and the surface of the nozzle plate 22 while maintaining the above-described effects. As a result, when the surface of the nozzle plate 22 is wiped by the wiping member 31, damage to the surface of the nozzle plate 22 by the wiping member 31 itself can be further reduced.

  Moreover, even if the ink composition contains an inorganic pigment as in the present embodiment, the above-described effects can be obtained effectively. Specifically, the ink composition containing an inorganic pigment is easily absorbed by the inside of the wiping member 31, and since the deposit on the nozzle plate and the surface of the wiping member 31 are softer during the cleaning operation, The damage is further reduced. As a result, the ejection of the ink composition can be maintained in a more stable state.

(Examples, comparative examples and evaluation)
Hereinafter, the ink jet recording apparatus according to the present invention will be described in more detail with reference to examples of cleaning liquids based on specific combinations of compositions, comparative examples, and evaluation results thereof.
Note that these do not limit the scope of the present invention.

<Inkjet recording apparatus>
As the ink jet recording apparatus 1, a PX-H10000 (manufactured by Seiko Epson Corporation) modified machine was used. The modified part is that the recording head 20, the wiping member 31, the pressing roller 34, the wiper unit driving mechanism, and the like are provided. The recording head 20 is provided with a nozzle plate 22 (silicon nozzle plate) with a liquid repellent film 24 and a nozzle plate cover 25 as shown in FIGS. The pressing roller 34 was provided with an elastic member.

<Nozzle plate>
The nozzle plate 22 was made of single crystal silicon. On the surface of the nozzle plate 22, a silicon oxide film (SiO ₂ film) formed by a CVD method was formed by introducing SiCl ₄ and water vapor into a chemical vapor deposition (CVD) reactor. The thickness of the SiO ₂ film was 50 nm. Further, oxygen plasma treatment is performed, and then a chemical vapor deposition method (CVD) is performed using C ₈ F ₁₇ C ₂ H ₄ SiCl ₃ to form a water repellent film (thickness 10 nm) on the SiO ₂ film. A silicon nozzle plate with a water repellent film was produced.

<Wiping member>
As the wiping member 31, a non-woven cupra [density 0.01 (g / cm ² ), cloth thickness 0.4 mm] was used. A roller having a Shore A hardness of 30 was used as the elastic member. The Shore A hardness is measured by preparing a sheet-like sample by press-molding the outer layer of a foam-molded roller or a thermoplastic elastomer before foam-molding at a temperature of 200 ° C., and the sheet-like sample is subjected to ATSM D-2240. The measurement was performed in accordance with the measurement method specified in 1. In Comparative Example 2, a rubber blade was used instead of the wiping member 31 and the elastic member.

<Wiper unit drive mechanism>
The wiper unit driving mechanism presses the wiping member 31 with a predetermined load from the side opposite to the side contacting the nozzle plate 22 of the recording head 20 with a predetermined load to contact the surface of the nozzle plate 22 and wipes. By moving the member 31 and the recording head 20 relative to each other, the wiping member 31 performs a cleaning operation for removing the ink composition adhering to the surface of the nozzle plate 22. The pressing load was 300 gf. The wiping speed was 5 cm / s.

<Ink composition>
Table 1 shows the compositions of the ink compositions specifically adjusted. The main materials of the ink composition are as follows.
Coloring material: Carbon black (CI pigment black 7, average particle diameter 100 nm)
Organic solvent: 1,2-hexanediol, 2-pyrrolidone, propylene glycol Resin: Styrene-acrylic acid copolymer resin emulsion (Tg 85 ° C., average particle size 140 nm), polyethylene wax emulsion (AQUACER 515 (produced by Big Chemie Japan))
Surfactant: Silicone surfactant (BYK348 (manufactured by Big Chemie Japan))
Antifoaming agent: Acetylene glycol antifoaming agent (Surfinol DF110D, HLB value = 3 (manufactured by Nissin Chemical Industry Co., Ltd.))
pH adjuster: Triethanolamine

  The average particle size was measured in accordance with the trade name “Microtrac UPA” of Nikkiso Co., Ltd. In addition, Tg was measured using a dried product of emulsion as a sample and using a trade name “DSC-6200R” manufactured by SII Nano Technologies, Inc.

<Cleaning liquid>
Table 2 shows the composition of the cleaning liquid specifically adjusted. Cleaning liquid compositions 1 to 5 were prepared as examples of the present embodiment, and cleaning liquid composition 6 was adjusted as a comparative example.
The main materials of the cleaning liquid are as follows.
Sugar: Reducing sugar HS-500 (manufactured by Hayashibara Corporation; sugar composition = monosaccharide 37-43 wt%, disaccharide 26-32 wt%, 3 sugar 14-20 wt%, 4 sugar or more 12-19 wt%) , Trehalose EO / PO copolymer 1: n1 + n2 = 5, m = 30
EO / PO copolymer 2: n1 + n2 = 25, m = 30
Lubricant: Polyethylene wax AQ515 (manufactured by Big Chemie Japan)
Surfactant: Acetylene glycol surfactant Olfine E1010 (manufactured by Nissin Chemical)
Other humectants: Polyethylene glycol (weight average molecular weight 200)

Evaluation was performed as follows about cleaning property and liquid repellent film preservability.
<Evaluation of cleaning properties>
Using a PX-H10000 remodeling machine, printing was performed for 20 minutes using the ink composition shown in Table 1, and then the cleaning operation shown in Table 3 was performed. This cycle is repeated 50 times, and the degree of ink adhesion at the lip portion (the portion where the nozzle plate cover 25 protrudes from the nozzle plate 22 (see FIGS. 2A and 2B)) (ink adhesion width from the edge of the lip portion) ) Was observed and the following evaluations were made. The results are shown in Table 4.
A: Substantially no adhesion to the lip.
(Less than 0.1mm from the edge of the lip)
B: Adherence is observed on the lip, but there is no significant effect on cleaning.
(0.1mm or more and less than 0.6mm from the edge of the lip)
C: The adhesion of the lip portion greatly affects the cleaning.
(0.6mm or more from the edge of the lip)

<Evaluation of storage stability of liquid repellent film>
Using a PX-H10000 remodeling machine, a cleaning operation (operation of sucking ink in the recording head 20 using a suction pump) was performed, and then the cleaning operation shown in Table 3 was performed. This cycle was repeated 12,000 times. Thereafter, the state of the liquid repellent film 24 in the vicinity of the nozzle (near the discharge port 23) was measured with an optical microscope, and the following evaluation judgment was performed. The results are shown in Table 4.
A: Level at which water-repellent film peeling cannot be observed B: Water-repellent film is slightly peeled and discolored, but has no effect on ejection C: Level at which water-repellent film on the entire nozzle surface is peeled off and has great influence on ejection

  As is clear from the results in Table 4, according to the present embodiment, the liquid repellent film 24 is maintained in a favorable range while the cleaning property is ensured.

  DESCRIPTION OF SYMBOLS 1 ... Inkjet recording device, 3 ... Carriage, 4 ... Carriage drive mechanism, 5 ... Control board, 6 ... Ink cartridge, 8 ... Platen, 10 ... Recording medium, 20 ... Recording head, 21 ... Nozzle, 22 ... Nozzle plate, 23 ... Discharge port, 24 ... Liquid repellent film, 25 ... Nozzle plate cover, 26 ... Nozzle chip, 30 ... Wiper unit, 31 ... Wiping member, 32 ... Feeding roller, 33 ... Removal roller, 34 ... Pressing roller, 35 ... Enclosure.

Claims (8)

A plurality of nozzles for discharging the ink composition;
A nozzle plate having discharge ports of the plurality of nozzles;
A cleaning liquid for wetting the ink composition adhering to the surface of the nozzle plate;
Wiping member that wipes the surface of the nozzle plate and has liquid absorbency,
A moving mechanism that varies a relative position between the nozzle plate and the wiping member,
The inkjet recording apparatus, wherein the cleaning liquid contains at least one of a saccharide, an EO / PO copolymer, and a lubricant.   The inkjet recording apparatus according to claim 1, wherein the saccharide is a disaccharide or more polysaccharide. When the EO / PO copolymer has an EO polymerization degree of n and a PO polymerization degree of m,
The inkjet recording apparatus according to claim 1, wherein 5 ≦ n ≦ 30, 5 ≦ m ≦ 50, and n ≦ m.   The inkjet recording apparatus according to any one of claims 1 to 3, wherein the lubricant is a polyolefin wax.   5. The ink jet recording apparatus according to claim 1, wherein a content of the saccharide or the EO / PO copolymer contained in the cleaning liquid is 5% by weight or more. 6.   6. The ink jet recording apparatus according to claim 1, wherein a content of the lubricant contained in the cleaning liquid is 1% by weight or more and 5% by weight or less.   The ink jet recording apparatus according to claim 1, wherein a liquid repellent film is formed on the surface of the nozzle plate.   The ink jet recording apparatus according to claim 1, wherein the ink composition contains an inorganic pigment.

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