JP2007253392A - Maintenance method for inkjet recorder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a maintenance method for an inkjet recorder whereby the sure and stable suction recovering operation can be maintained for a long time when a pigment ink is used, and also the trouble such as ink contamination and ink color mixing at delivering openings can be reduced by lessening ink contamination of an ink absorber because of the suction recovery. <P>SOLUTION: An ink set comprising at least one kind of the pigment ink and a clear ink which comprises at least one kind of water-soluble organic solvents as a good solvent to the pigment ink is loaded in a recording head. The delivering openings for the pigment ink and delivering openings for the clear ink of the recording head are capped by the same cap. Suction of the pigment ink from the delivering openings for the pigment ink, and suction of the clear ink from the delivering openings for the clear ink are carried out simultaneously by a suction means connected to the cap. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a maintenance method for an ink jet recording apparatus that performs recording by discharging ink from a recording head to a recording medium.

  A recording apparatus having functions such as a printer, a copying machine, and a facsimile is configured to record an image (including characters and symbols) on a recording medium such as paper, cloth, a plastic sheet, and an OHP sheet based on image information. Has been. There are a serial type and a line type as a recording method in the recording apparatus. The serial type is a system in which an image is recorded while alternately repeating main scanning for moving the recording head along the recording medium and sub-scanning for conveying the recording medium by a predetermined pitch. The line type is a system in which an image is recorded only by sub-scanning of the recording medium while recording one line at a time by using a recording head extending in the width direction of the recording medium. The recording apparatus can be divided into an ink jet recording apparatus, a thermal transfer recording apparatus, a laser recording apparatus, a thermal recording apparatus, a wire dot recording apparatus, and the like depending on the recording method of the recording head.

  Among these, in an ink jet recording apparatus that performs recording by discharging ink from a recording head to a recording medium, a dye having excellent color development and stability is used as a coloring material of the ink composition. However, although dyes have the above-mentioned advantages, there are cases where the recorded images are not sufficient in terms of water resistance, light resistance, etc., and improvements are required. In order to improve these, many so-called pigment inks using organic pigments or carbon black instead of dyes have been proposed. On the other hand, in an ink jet recording apparatus that discharges ink from fine discharge ports, air bubbles are mixed, dust enters, and the ink meniscus retreats at the discharge ports during recording. There is. In addition, as the standing time elapses, ink thickening or sticking may occur near the ejection port. In such a state, ejection failure may occur, and the quality of the recorded image may deteriorate. In order to prevent these situations, a recovery operation for recovering the ink discharge from the discharge port to a normal state and a preliminary ink discharge operation for stabilizing the ink discharge characteristics in advance (hereinafter referred to as “preliminary discharge”). Etc.) are performed.

  As one of recovery operations for discharging ink from the ejection port for such maintenance, a suction recovery operation for sucking ink from the ejection port is performed. This suction recovery operation is an operation for forcibly discharging the ink in the discharge port by applying a negative pressure to the discharge port by a suction means such as a pump connected to the cap while the discharge port is capped with a cap. Done. The sucked ink is guided to an ink reservoir through, for example, a tube and is stored as waste ink. In this case, in order to prevent ink from leaking to the outside from the supply port to the ink reservoir, the ink reservoir (waste ink collecting part) is constituted by a cartridge, and a member having a high water absorption force (hereinafter referred to as “ink absorber” ”).

  This ink absorber is composed of, for example, a high-density fiber structure such as water-absorbing paper or felt, a foam molding material such as polyurethane or PVA (polyvinyl alcohol), or an absorbent member containing a water-absorbing polymer. In addition, a member having high ink absorptivity (hereinafter referred to as “ink absorber”) is also housed in a cap for capping the ejection ports arranged on the ejection surface of the recording head. The ink absorber in the cap is also composed of the same members as the ink absorber in the waste ink recovery unit.

Therefore, in the process of carrying out various evaluations by mounting the pigment ink composition on the ink jet recording apparatus, the pigment ink composition is fixedly deposited on the ink absorber, thereby causing a phenomenon that the pigment ink is not gradually absorbed. It was found. For such inconvenience, Patent Document 1 discloses that a dye ink that is harder to fix and deposit than a pigment ink is used and a recovery unit that sucks the pigment ink together with the dye ink is used. Further, Patent Document 2 discloses a suction recovery means in which suction is easily and reliably performed by dissolving pigment ink fixed and deposited by a cap for a pigment ink head or an ink absorbing member therein with dye ink. Are listed.
JP 2000-198956 A JP 2003-154681 A

  The suction recovery means described in Patent Document 1 and Patent Document 2 can be applied to an ink jet recording apparatus equipped with pigment ink and dye ink, but can be applied to an ink jet recording apparatus using only pigment ink. Can not. Therefore, as a result of various investigations to solve such problems, the present inventors have found the following. That is, when using a pigment ink, at least one pigment ink and a clear ink containing at least one water-soluble organic solvent that is a good solvent for the pigment ink are prepared. The recovery system unit for the pigment ink composition discharge port and the clear ink composition discharge port is made common. By using such means, it is possible to solve the above-mentioned problems by causing the clear ink to have the function of suppressing the fixed deposition of the pigment ink in the ink absorber and the function of redispersing the pigment fixed deposit. it can.

  An object of the present invention is to provide a maintenance method of an ink jet recording apparatus capable of maintaining a reliable and stable suction recovery operation for a long time when using a pigment ink. Another object of the present invention is to provide a maintenance method for an ink jet recording apparatus that can reduce inconveniences such as ink smearing and ink color mixing at the ejection port by reducing ink smearing of the ink absorber due to suction recovery. .

  The present invention relates to a maintenance method for an ink jet recording apparatus that performs recording by discharging ink from a recording head to a recording medium. An ink set comprising at least one pigment ink and a clear ink containing at least one water-soluble organic solvent that is a good solvent for the pigment ink is mounted on the recording head. Also, the pigment ink ejection port and the clear ink ejection port of the recording head are capped with the same cap. Accordingly, the suction means connected to the cap simultaneously performs suction of the pigment ink from the discharge port of the pigment ink and suction of the clear ink from the discharge port of the clear ink.

  According to the present invention, when using pigment ink, a reliable and stable suction recovery operation can be maintained over a long period of time. Further, by reducing ink stains on the ink absorber due to suction recovery, inconveniences such as ink stains and ink color mixing at the discharge ports can be reduced.

Hereinafter, embodiments of the present invention will be specifically described. Note that the same reference numerals denote the same or corresponding parts throughout the drawings.
[Inkjet recording device]
First, the ink jet recording apparatus will be described. FIG. 1 is a perspective view showing an embodiment of an ink jet recording apparatus to which the present invention is applied. In FIG. 1, a recording medium such as a recording sheet fed one by one from a sheet feeding unit 115 is transported through a platen 106 by a transport roller 105 held by a chassis 103. A carriage 101 that can reciprocate in the width direction of the recording medium is equipped with a recording head 107 that faces the platen 106 with a predetermined gap. The carriage 101 on which the recording head 107 is mounted is guided and supported so as to be able to reciprocate along the guide shaft 102 and the guide rail 104. This reciprocation of the carriage is performed by transmitting a driving force from a driving source (not shown) via the belt 109.

  Therefore, an image by the recording head 107 is recorded on a recording medium that is conveyed on the platen 106 while being sandwiched between the conveying roller 105 and the pinch roller 111 and between the discharging roller 112 and the discharging auxiliary roller (spurs). . That is, recording is performed by ejecting ink from a recording head to a recording medium based on recording data (information). By alternately repeating the recording for one line by the movement of the carriage and the paper feeding by the conveying roller 105, the image recording of the entire recording medium is performed. The recorded recording medium is discharged out of the apparatus main body through the discharge roller 112.

  In the ink jet recording apparatus, since ink is discharged from a fine discharge port provided on the discharge surface of the recording head 107 and recorded, it is necessary to prevent clogging of the discharge port in order to maintain the quality of a recorded image. . As a means for this, a recovery mechanism 120 is provided at a predetermined position outside the recording area (for example, the home position of the recording head) to prevent clogging of the ejection port and maintain and recover the ink ejection performance. Yes. The recovery mechanism section is provided with a capping unit that closes the cap 121 to the discharge surface of the recording head and covers the discharge port during non-recording. In addition, the recovery mechanism unit 120 is provided with a suction pump 122 as negative pressure generating means connected to the cap 121. Further, the recovery mechanism unit 120 is provided with a wiper 123 for wiping and cleaning deposits on the discharge surface by using relative movement with respect to the discharge surface (surface on which the discharge ports are arranged) of the recording head 107. ing.

  The suction pump 122 operates in a capping state to apply a negative pressure to the discharge port, thereby sucking and discharging thickened ink, bubbles, and the like together with the ink from the discharge port. By such forced ink suction and discharge, the ink in the ejection port can be refreshed, and the ink ejection performance of the recording head can be maintained and recovered. A negative pressure generating means such as a tube pump or a piston pump is used as the suction pump 122. The tube pump is configured to generate a negative pressure in the tube by handling the tube of elastic material with a roller.

  FIG. 2 is a perspective view of the recording head 107 in FIG. In FIG. 2, the recording head 107 according to the present embodiment includes an ink discharge unit 21 and an ink storage unit 22. The ink storage unit 22 includes a clear ink storage unit 22L that stores clear ink, which will be described later, and color ink storage units 22Bk, 22C, 22M, and 22Y that store ink of each color. 22B is a black ink container, 22C is a cyan ink container, 22M is a magenta ink container, and 22Y is a yellow ink container. Thus, in the ink jet recording apparatus according to this embodiment, the recording head 107 is mounted with an ink set including at least one kind of pigment ink and clear ink.

  The ink storage unit 22 may be integrated with the ink discharge unit 21 or may be detachable. Further, the ink container may be configured to replace each ink at once, or may be configured to be replaceable for each ink individually. In the following description, when distinguishing each ink, after the number, “L” for clear ink, “Bk” for black ink, “C) for cyan ink, “M” is added for magenta ink, and “Y” is added for yellow ink. When an arbitrary ink is indicated or when all inks are indicated, they are indicated by a common number not added.

  FIG. 3 is a front view showing the ejection surface 31 of the recording head 107 as seen from the arrow 3-3 in FIG. On the ejection surface 31, an ejection port array 33 for ejecting each ink is formed. 33L is a clear ink discharge port array for discharging clear ink, and 33Bk is a black ink discharge port array 33B for discharging black ink. 33C is a cyan ink ejection port array that ejects cyan ink, 33M is a magenta ink ejection port array that ejects magenta ink, and 33Y is a yellow ink ejection port array that ejects yellow ink. In the example shown in the drawing, each discharge port array is composed of a plurality of discharge ports 35 arranged linearly at a constant pitch. Thus, in this embodiment, clear ink is used in addition to the four colors of inks having different color tones. Each ink container and the ejection port array are connected by separate ink flow paths so that each ink can be ejected independently.

  FIG. 4 is a perspective view showing the cap 121 and the suction pump 122 of the recovery mechanism unit 120 in FIG. FIG. 5 is a longitudinal sectional view showing the structure of the cap 121 of the recovery mechanism section 120 in FIG. 4 and 5, the cap 121 is held by a cap holder 125, and the cap holder is configured to be driven up and down in the vertical direction via a spring (not shown). When the recording head 107 is at the opposite position, the cap 121 can be brought into close contact with the ejection surface 31 by raising the cap holder 125. The cap 121 has a structure in which a shallow basin-shaped cap rubber 41 is closely fitted to a deep basin-shaped cap cover 42, and a lip portion that abuts the discharge surface 31 in a sealed state on the opening edge of the cap rubber 41. A (sealing portion) 43 is formed.

  A suction hole 44 is formed in a part of the cap rubber 41 (for example, the central portion). The suction hole protrudes to the outside (downward in the drawing) through the opening 45 of the cap cover 42, and is connected to the suction tube 47 in an airtight state at the opening 46 formed in the cap holder 125. The suction tube 47 is connected to a suction pump 122 which is a negative pressure generating means. The cap 121 of the present embodiment is configured to be able to be in close contact with the ejection surface 31 so as to cover all the ejection port arrays 33 (and hence all the ejection ports 35) of the recording head 121. Therefore, an ink absorber (cap absorber) 48 having high ink absorbability is loaded (arranged) inside the cap 121 (in the illustrated example, inside the cap rubber 41). In this case, by providing the suction hole 44 in the center portion of the cap rubber 41 (and hence the center portion of the ink absorber 48), the ink discharged in the cap 121 can be sucked without being retained. Further, the ink can be evenly sucked from all the discharge ports 35 arranged at the center and the end of the discharge surface.

  As shown in FIG. 4, the suction pump 122 is connected to an ink absorber 127 in the waste ink collection unit 126 via a waste ink tube 49. The waste ink collection unit is installed using, for example, a space at the bottom of the recording apparatus. The ink absorber 127 is also composed of an absorber having high ink absorptivity, like the ink absorber 48 in the cap 121. In addition to the function of sealing the discharge port 35, the cap 121 has a function of receiving ink discharged from the discharge port in the above-described suction recovery operation and preliminary discharge operation. That is, the ink received by the suction recovery operation or the preliminary ejection operation is sucked by the suction pump 122, introduced into the ink absorber 127 of the waste ink collection unit 126, and processed as waste ink.

  As the suction pump 122, those having various configurations can be used. For example, a piston / cylinder type pump or a tube pump is used. This tube pump generates a negative pressure suction force in the tube by squeezing the flexible tube connected to the cap with a roller or the like. This suction pump is driven by a recovery motor (not shown) that is a drive source of the recovery mechanism. References disclosing the configuration and operation of the tube pump used as the suction pump 122 include, for example, Japanese Patent Application Laid-Open No. 2000-110874 (Japanese Patent Application No. 10-293116) and Japanese Patent Application Laid-Open No. 2000-127450 (Japanese Patent Application Laid-Open No. 2000-127450). No. 10-321534). Further, there are JP-A No. 2000-15844 (Japanese Patent Application No. 10-199684), JP-A No. 11-342637 (Japanese Patent Application No. 10-166334), and the like.

  The cap rubber 41 of the cap 121 is formed of a rubber-like elastic material capable of sealing the discharge port 35 of the discharge surface 31, for example, an appropriate material having elasticity such as chlorinated butyl rubber. A cap spring (not shown) mounted between the cap holder 125 and its supporting member is effective for bringing the cap 121 into contact with the discharge surface 31 with appropriate pressure. In this case, by making the support portion of the cap holder 125 have a pin coupling structure, the entire peripheral surface of the cap 121 can be uniformly adhered to the discharge surface. As the material of the ink absorber 48 in the cap 121 and the ink absorber in the waste ink collection unit 126, a material having excellent ink transfer properties such as a foamed sponge is selected. Ink absorbers made of these materials are made by, for example, a punching die.

  FIG. 6 is a schematic diagram showing a drive mechanism of the wiper 123 in the recovery mechanism unit 120. In this embodiment, with respect to the recording head 107 stopped at a position facing the recovery mechanism unit 120, the tip of the blade-like wiper 123 made of an elastic member is pressed against the ejection surface 31 and elastically deformed like a bow. Rub in the state. The rubbing direction (wiping direction) may be the direction of the discharge port array 33 (arrangement direction of the discharge ports) or a direction intersecting therewith.

  In FIG. 6, a blade-like wiper 123 made of a rubber elastic material is held by a wiper holder 131. The wiper holder 131 is guided and supported so as to be able to reciprocate along a guide 132 provided in the recovery mechanism section 120. A rack gear (movable rack gear) 133 is formed below the wiper holder 131. On the other hand, a rack gear (fixed rack gear) 135 is provided on the base 134 of the recovery mechanism unit 120. Between these rack gears 133 and 135, a double gear 136 that is rotationally driven by a drive source such as a recovery motor is disposed. The double gear is integrally formed with a gear 137 that meshes with the movable side (wiper holder side) rack gear 133 and a gear 138 that meshes with the fixed side rack gear 135. Reference numeral 139 denotes a shaft of a double gear 136 driven by a recovery motor or the like.

  According to the configuration of FIG. 6, the wiper 123 can be moved along the guide 132 by rotationally driving the double gear 136, and the wiper moving direction (wiping direction indicated by a double-headed arrow EB) by forward and reverse rotation thereof. And return direction). FIG. 6 shows a state in which the ejection surface 31 is wiped and cleaned (wiping) by moving the wiper 123 in the right direction (wiping direction) in a state where the wiper 123 is pressed against the ejection surface 31 of the recording head 107.

  FIG. 7 is a partial perspective view illustrating another configuration example of the ink ejection unit 21 of the recording head 107. In FIG. 7, an ink cartridge for each color ink (not shown) is detachably attached to the recording head 107. The ink discharge unit 21 of the recording head 107 is provided with an individual liquid chamber (or sub tank) 24 for holding ink supplied from each ink cartridge. That is, the clear ink is supplied from the clear ink cartridge to the clear ink liquid chamber 24L through the liquid path 25L. Black ink is supplied to the black ink liquid chamber 24 from the black ink cartridge through the liquid path 25Bk. Similarly, yellow ink, magenta ink, and cyan ink are individually supplied to the yellow, magenta, and cyan liquid chambers 24Y, 24M, and 24C through the liquid passages 25Y, 25M, and 25C, respectively.

  As described above, the present invention provides a novel maintenance method in an ink jet recording apparatus that performs recording by discharging ink from a recording head to a recording medium. In the maintenance method of the ink jet recording apparatus according to the present embodiment, the recording head includes at least one pigment ink and a clear ink containing at least one water-soluble organic solvent that is a good solvent for the pigment ink. Equipped with an ink set. Also, the pigment ink ejection port and the clear ink ejection port of the recording head are capped with the same cap. Therefore, the suction means connected to the cap is configured to simultaneously suck the pigment ink from the pigment ink discharge port and the clear ink from the clear ink discharge port.

  According to this configuration, the following operational effects can be obtained. That is, even when pigment ink is used as each color ink, fluidity can be imparted to the pigment ink in the ink absorber in the cap by sucking and recovering the clear ink simultaneously with the pigment ink. That is, even when a fixed deposit of pigment ink already exists on the ink absorber in the cap, fluidity can be imparted to the fixed deposit. As a result, the remaining amount of pigment ink in the ink absorber in the cap can be reduced or eliminated. Thereby, the production | generation of a pigment fixed deposit is suppressed. Further, by preliminarily discharging the pigment ink and the clear ink to the ink absorber in the cap, the fixed deposit of the pigment ink remaining on the ink absorber can be similarly removed.

  That is, according to the present invention, there is provided a maintenance method for an ink jet recording apparatus capable of maintaining a reliable and stable suction recovery operation over a long period of time when using pigment ink. Further, there is provided a maintenance method for an ink jet recording apparatus capable of reducing inconveniences such as ink smearing and ink color mixing at the ejection port by reducing ink smearing of the ink absorber due to suction recovery.

In the maintenance method for the ink jet recording apparatus according to this embodiment, it is preferable that at least one of the good solvents is a low-volatile solvent. Moreover, it is preferable that the pigment of the pigment ink is an alkali-soluble pigment. Moreover, it is preferable that PH of the said clear ink is higher than PH of the said pigment ink. Further, it is preferable that the clear ink is preliminarily ejected to the cap after the pigment ink is preliminarily ejected to the cap. Further, it is preferable that after the pigment ink and the clear ink are sucked, the clear ink is preliminarily discharged to the cap.
In the present embodiment, it is preferable to increase the suction amount of the clear ink when sucking the pigment ink and the clear ink at the same time. For this reason, the cross-sectional area of the clear ink discharge port is made larger than that of the pigment ink discharge port. Also, the clear ink discharge port is made larger than the pigment ink discharge port to increase the discharge amount of the clear ink, so that the preliminary discharge time to the ink absorber 48 in the cap 121 can be shortened. Become.

  In the present embodiment, the material of the ink absorber 48 in the cap 121 and the ink absorber 127 in the waste ink collection unit 126 is preferably, for example, a laminated sheet of paper or an absorber including a polymer absorber. Moreover, you may use the foam formation material by high density fiber structure polyurethanes, such as felt, cellulose, PVA, EVA. Further, a water-absorbing material described later containing a water-absorbing polymer such as acrylic acid graft starch, acrylic salt graft starch, vinyl alcohol acrylic acid block copolymer, and vinyl alcohol acrylic salt block copolymer may be used. Furthermore, a water-absorbing material described later containing a water-absorbing polymer such as cross-linked polyacrylic acid, cross-linked polyacrylic salt, modified PVA, polystyrene sulfonic acid, cellulose ether, and carboxymethyl cellulose may be used. Moreover, the ink absorber made of these materials can be made by, for example, a punching die.

Hereinafter, preferred embodiments of the present invention will be specifically described.
[Clear ink and maintenance method]
First, the good solvent in the present invention will be described. Although details of the definition will be described later, a solvent that can maintain the dispersion stability of the pigment in the presence of a water-soluble organic solvent regardless of the pigment dispersion method is defined as a good solvent. On the other hand, those that inhibit the dispersion stability of the pigment are used as poor solvents. When selecting a good solvent to be used in the present invention, it is preferable to select from the results of observing the stability of the dispersion state of the pigment with respect to the solvent. The inventors selected the good solvent as follows. First, the pigment ink used for the petri dish filled with the solvent to be selected was dropped and allowed to stand for one day, and then the degree of diffusion of the pigment in this solvent was observed. The solvent in which the pigment diffused in the solvent after dropping the pigment ink was defined as a good solvent, and the solidified material without being diffused was defined as a poor solvent.

  For example, as a good solvent when a pigment dispersed with a styrene-acrylic acid copolymer is used for pigment ink, glycerin, ethylene glycol, diethylene glycol, and the like can be given. The clear ink used in the present invention has a function of suppressing the fixed deposition of the pigment ink and a function of redispersing the pigment fixed deposit. For this reason, it is essential that the clear ink contains a good solvent as described above. In this way, the clear ink is sucked from the ejection port simultaneously with the pigment ink, whereby fluidity is imparted to the pigment ink in the ink absorber 74. Further, fluidity is also imparted to the pigment deposit already present in the ink absorber. As a result, the residual amount of the pigment ink in the ink absorber is reduced, and the generation of the pigment fixed deposit is suppressed.

  The clear ink may be preliminarily ejected to the ink absorber after the pigment ink and the clear ink are recovered by suction, or after the pigment ink is preliminarily ejected to the ink absorber. By such preliminary discharge of clear ink, it is possible to suppress sticking accumulation of pigment ink remaining in the ink absorber. At that time, it is preferable that the ink absorber keeps a certain level of wettability by always filling the ink absorber with clear ink. For this reason, it is preferable that at least one of the good solvents contained in the clear ink has low volatility. Thus, it is preferable that the water-soluble organic solvent contained in the clear ink used in the present invention is a good solvent for the pigment ink and has low volatility.

  The low volatility solvent in the present invention refers to a solvent having a vapor pressure of 10 Pa or less at 20 ° C. Specific examples include ethylene glycol, diethylene glycol, dipropylene glycol, hexylene glycol 1,3 butanediol, 1,5 pentanediol, and the like. Furthermore, triethylene glycol, polyethylene glycol (having a molecular weight of 200 to 600 is preferable), glycerin, diglycerin, 1,2,6 hexanetriol, 3 methylpentane, 1,3,5 triol and the like can be mentioned. The above-mentioned solvent species are merely examples. The water-soluble organic solvent actually used depends on the characteristics of the pigment ink used, but can be appropriately selected from the following water-soluble organic solvent species.

  For example, C1-C4 alkyl alcohols, such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol, are mentioned. Further, amides such as dimethylformamide and dimethylacetamide; ketones or ketoalcohols such as acetone and diacetone alcohol; and ethers such as tetrahydrofuran and dioxane. Moreover, polyalkylene glycols, such as polyethylene glycol and polypropylene glycol, are mentioned. Further, alkylene glycols in which an alkylene group contains 2 to 6 carbon atoms such as ethylene glycol, propylene glycol, butylene glycol, triethylene glycol, and 1,2,6-hexanetriol are exemplified. Furthermore, alkylene glycols in which the alkylene group contains 2 to 6 carbon atoms such as thiodiglycol, hexylene glycol, diethylene glycol and the like are also included.

  Moreover, lower alkyl ether acetates, such as polyethylene glycol monomethyl ether acetate, and glycerol are mentioned. Further, lower alkyl ethers of polyhydric alcohols such as ethylene glycol monomethyl (or ethyl) ether, diethylene glycol methyl (or ethyl) ether, triethylene glycol monomethyl (or ethyl) ether, and the like can be given. Furthermore, polyhydric alcohols such as trimethylolpropane and trimethylolethane, N-methyl-2-pyrrolidone, 2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone and the like can be mentioned.

  As water, it is desirable to use deionized water. The content of the water-soluble organic solvent contained in the clear ink in the present invention is not particularly limited, but is preferably in the range of about 3 to 50% by mass with respect to the total mass of the clear ink. Further, the content of water in the clear ink is preferably in the range of about 50 to 95% by mass with respect to the total mass of the clear ink. Furthermore, in addition to the above components, a surfactant, antifoaming agent, antiseptic or antifungal agent, etc. may be added in order to obtain an ink having desired physical properties as well as adding a moisturizing agent as necessary. It may be added.

  If the degree of pigment dispersion in the present invention depends on the pH value, it is preferable to adjust the pH value of the clear ink to a pH range that promotes pigment dispersion. For example, in the case of a pigment ink using an alkali-soluble pigment, the formation of a pigment-fixed deposit can be more effectively suppressed by adjusting the pH of the clear ink to a value higher than that of the pigment ink. Furthermore, a solvent or the like for suppressing curling or cockling of the recording medium may be added as long as the effects of the present invention are not impaired. As a result, further functions such as curling and cockling of the printed matter can be provided.

[Pigment ink composition]
Examples of the color material used in the ink composition of the present invention include pigments (microencapsulated pigments, and further colored resins are also included in the category of pigments). This coloring material will be described in detail below. Examples of the pigment used include carbon black and organic pigments.

(Carbon black)
As the carbon black, for example, carbon black pigments such as furnace black, lamp black, acetylene black, and channel black can be used. In this case, for example, a Raven 7000, a Ravan 5750, a Ravan 5250, a Ravan 5000, a Ravan 3500, and a Ravan 2000 (manufactured by Columbia) can be used. Also, Rayvan 1500, Rayvan 1250, Rayvan 1200, Rayvan 1190ULTRA-II, Rayvan 1170, Rayvan 1255 (manufactured by Columbia Co., Ltd.) can be used.

  Furthermore, as the carbon black, for example, Black Pearls L, Legal 400R, Legal 330R, Legal 660R (manufactured by Cabot Corporation) can be used. Further, Mogul L, Monarch 700, Monak 800, Monak 880, and Monak 900 (manufactured by Degussa) can be used. Further, color black S150, color black S160, and color black S170 (manufactured by Degussa) can be used. Moreover, Monak 1000, Monak 1100, Monak 1300, Monak 1400, and Vulcan XC-72R (manufactured by Cabot Corporation) can also be used. Also, Color Black FW1, Color Black FW2, Color Black FW2V, Color Black FW18, and Color Black FW200 (manufactured by Degussa) can be used. Furthermore, color black S150, color black S160, and color black S170 (manufactured by Degussa) can be used.

  Also, Printex 35, Printex U, Printex V, Printex 140U, Printex 140V (manufactured by Degussa) can be used. Furthermore, Special Black 6, Special Black 5, Special Black 4A, Special Black 4 (manufactured by Degussa) can be used. Further, as carbon black, no. 25, no. 33, no. 40, no. 47, no. 52, no. 900, no. 2300, MCF-88, MA600, MA7, MA8, MA100 (manufactured by Mitsubishi Chemical Corporation) and the like can be used. However, it is not limited to these, and conventionally known carbon black can be used. Further, magnetic fine particles such as magnetite and ferrite, titanium black and the like may be used as the black pigment.

(Organic pigment)
Specific examples of the organic pigment include insoluble azo pigments such as toluidine red, toluidine maroon, Hansa Yellow, Benzidine Yellow, and pyrazolone red. Further, soluble azo pigments such as ritole red, helio bordeaux, pigment scarlet, and permanent red 2B can be mentioned. Moreover, derivatives from vat dyes such as alizarin, indanthrone, thioindigo maroon and the like can be mentioned. Further, phthalocyanine pigments such as phthalocyanine blue and phthalocyanine green can be mentioned. Further examples include quinacridone pigments such as quinacridone red and quinacridone magenta, and perylene pigments such as perylene red and perylene scarlet.

  Specific examples of organic pigments include isoindolinone pigments such as isoindolinone yellow and isoindolinone orange, and imidazolone pigments such as benzimidazolone yellow, benzimidazolone orange and benzimidazolone red. It is done. Further, pyranthrone pigments such as pyranthrone red and pyranthrone orange are listed. Moreover, a thioindigo pigment, a condensed azo pigment, a thioindigo pigment, and the like can be given. Furthermore, other pigments such as flavanthrone yellow, acylamide yellow, quinophthalone yellow, nickel azo yellow, copper azomethine yellow, perinone orange, anthrone orange, dianthraquinonyl red, dioxazine violet and the like can be mentioned.

  When the organic pigment in the present invention is represented by a color index (CI) number, C.I. I. Pigment yellow 12, 13, 14, 17, 20, 24, 74, 83, 86, 93, 109, 110, 117, 120, and the like. Furthermore, 125, 128, 137, 138, 147, 148, 151, 153, 154, 166, 168 etc. can be illustrated. In addition, C.I. I. Pigment Orange 16, 36, 43, 51, 55, 59, 61 and the like can be exemplified. In addition, C.I. I. Pigment Red 9, 48, 49, 52, 53, 57, 97, 122, 123, 149, 168, 175, 176, 177 and the like can be exemplified. Furthermore, C.I. I. Pigment Red 180, 192, 215, 216, 217, 220, 223, 224, 226, 227, 228, 238, 240 and the like can also be exemplified. In addition, C.I. I. Pigment Violet 19, 23, 29, 30, 37, 40, 50 and the like can be exemplified. In addition, C.I. I. Pigment Blue 15, 15: 3, 15: 1, 15: 4, 15: 6, 22, 60, 64, and the like. Furthermore, C.I. I. Pigment green 7, 36, and C.I. I. Examples thereof include CI Pigment Brown 23, 25, 26, and the like. In addition to these organic pigments, conventionally known organic pigments can also be used.

(Dispersant)
When using the above-described carbon black or organic pigment, it is preferable to use a dispersant in combination. As the dispersant, it is preferable to use a dispersant capable of stably dispersing the pigment in an aqueous medium by the action of an anionic group. Specific examples of the dispersant include, for example, a styrene-acrylic acid copolymer, a styrene-acrylic acid-acrylic acid alkyl ester copolymer, a styrene-maleic acid copolymer, and a styrene-maleic acid-acrylic acid alkyl ester copolymer. Coalesce is mentioned. Also, styrene-methacrylic acid copolymer, styrene-methacrylic acid-acrylic acid alkyl ester copolymer, styrene-maleic acid half ester copolymer, vinyl naphthalene-acrylic acid copolymer, vinyl naphthalene-maleic acid copolymer Is mentioned. Moreover, a styrene-maleic anhydride-maleic acid half ester copolymer is mentioned. Furthermore, salts of these copolymers can also be mentioned. These dispersants preferably have a weight average molecular weight in the range of 1,000 to 30,000, and particularly preferably in the range of 3,000 to 15,000.

(Self-dispersing pigment)
As the coloring material, a pigment that can be dispersed in an aqueous medium without a dispersant by bonding an ionic group (anionic group) to the pigment surface, that is, a self-dispersing pigment can also be used. An example of such a pigment is self-dispersing carbon black. Examples of the self-dispersing carbon black include those in which an anionic group is bonded to the surface of the carbon black.

"Anionic carbon black"
Examples of the anionic carbon black include those obtained by bonding at least one anionic group to the surface of the carbon black. As a specific example of such anionic carbon black, for example, at least one anionic group of —COO (M2), —SO3 (M2), —PO3H (M2), and —PO3 (M2) 2 is bonded. Can be mentioned. In these anionic groups, M2 represents a hydrogen atom, an alkali metal, ammonium, or organic ammonium. Among these, carbon black charged anionic by bonding -COO (M2) or -SO3 (M2) to the carbon black surface has good dispersibility in the ink. Particularly preferably used.

  By the way, specific examples of the alkali metal among those represented by M2 in the hydrophilic group include, for example, Li, Na, K, Rb and Cs. Specific examples of organic ammonium include methylammonium, dimethylammonium, trimethylammonium, ethylammonium, diethylammonium, triethylammonium and the like. Moreover, methanol ammonium, dimethanol ammonium, trimethanol ammonium, etc. can also be mentioned. An ink containing self-dispersing carbon black in which M2 is ammonium or organic ammonium can further improve the water resistance of the recorded image, and can be particularly preferably used in this respect. This is considered to be due to the fact that when the ink is applied onto the recording medium, ammonium is decomposed and ammonia is evaporated.

  Examples of the self-dispersing carbon black in which M2 is ammonium include a method of substituting M2 with ammonium by using an ion exchange method for self-dispersing carbon black in which M2 is an alkali metal. Moreover, the method etc. which add M2 to ammonium by adding ammonium hydroxide after adding an acid to make H type | mold etc. are also mentioned. An example of a method for producing an anionically charged self-dispersing carbon black is a method of oxidizing carbon black with sodium hypochlorite. According to this method, a —COONa group can be chemically bonded to the carbon black surface.

  By the way, the various hydrophilic groups described above may be directly bonded to the surface of carbon black. Alternatively, another atomic group may be interposed between the carbon black surface and the hydrophilic group, and the hydrophilic group may be indirectly bonded to the carbon black surface. Here, specific examples of the other atomic groups include, for example, a linear or branched alkylene group having 1 to 12 carbon atoms, a substituted or unsubstituted phenylene group, and a substituted or unsubstituted naphthylene group. . Specific examples of the substituent for the phenylene group and the naphthylene group include, for example, a linear or branched alkylene group having 1 to 6 carbon atoms. Specific examples of combinations of other atomic groups and hydrophilic groups include, for example, —C 2 H 4 COO (M 2), —Ph—SO 3 (M 2), —Ph—COO (M 2), etc. (where Ph is phenyl Represents a group).

  As for the self-dispersing carbon black, two or more of the above listed materials may be appropriately selected and used as the ink coloring material. Further, the addition amount of the self-dispersing carbon black in the ink is preferably in the range of 0.1 to 15% by mass, particularly 1 to 10% by mass with respect to the total mass of the ink. By setting this range, the self-dispersing carbon black can maintain a sufficiently dispersed state in the ink. Furthermore, for the purpose of adjusting the color tone of the ink, a dye may be added as a coloring material in addition to the self-dispersing carbon black.

"Colored fine particles and microencapsulated pigments"
As the color material, in addition to the above, pigments microencapsulated with a polymer or the like, or colored fine particles in which the periphery of resin particles is coated with a color material can be used. The microcapsule inherently has dispersibility in an aqueous medium, but a dispersant as described above may be further coexisted in the ink in order to improve dispersion stability. Moreover, when using colored fine particles as a coloring material, it is preferable to use the anionic dispersant described above.

[Aqueous medium]
The aqueous medium in which the coloring material as described above is dispersed is not particularly limited, but specific examples include those exemplified below. For example, C1-C4 alkyl alcohols, such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol, are mentioned. Moreover, amides, such as dimethylformamide and dimethylacetamide, and ketones or ketoalcohols, such as acetone and diacetone alcohol, are mentioned. Furthermore, ethers such as tetrahydrofuran and dioxane, and polyalkylene glycols such as polyethylene glycol and polypropylene glycol can be mentioned.

  Furthermore, alkylene glycols in which the alkylene group contains 2 to 6 carbon atoms, such as ethylene glycol, propylene glycol, butylene glycol, triethylene glycol, and 1,2,6-hexanetriol. Furthermore, alkylene glycols in which the alkylene group contains 2 to 6 carbon atoms such as thiodiglycol, hexylene glycol, diethylene glycol and the like are also included. Moreover, lower alkyl ether acetates, such as polyethylene glycol monomethyl ether acetate, are mentioned. In addition, glycerin and lower alkyl ethers of polyhydric alcohols such as ethylene glycol monomethyl (or ethyl) ether, diethylene glycol methyl (or ethyl) ether, triethylene glycol monomethyl (or ethyl) ether, and the like can be given. Furthermore, polyhydric alcohols such as trimethylolpropane and trimethylolethane, N-methyl-2-pyrrolidone, 2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone and the like can be mentioned.

  The water-soluble organic solvents as described above can be used alone or as a mixture. Moreover, it is preferable to use deionized water as water. Moreover, the effect of the present invention can be further enhanced by using the same water-soluble organic solvent as described above as the aqueous medium used for the clear ink. The content of the water-soluble organic solvent contained in the ink composition used in the present invention is not particularly limited, but is preferably in the range of about 3 to 50% by mass with respect to the total mass of the ink composition. Further, the content of water contained in the ink composition is preferably in the range of about 50 to 95% by mass with respect to the total mass of the ink composition. In addition to the above components, it is preferable to add a humectant as necessary. In addition, a surfactant, an antifoaming agent, a preservative, an antifungal agent, or the like may be added in order to obtain an ink having a desired physical property value.

[Ink set]
The color tone of the ink that constitutes the ink set in combination with the clear ink is, for example, an ink that exhibits at least one color tone selected from yellow, magenta, cyan, orange, red, green, blue, violet, and black. That's fine. However, the color tone of the ink is not limited to these. Specifically, it can be used by appropriately selecting from the above-described color materials so as to obtain an ink having a desired color tone. Here, the content of the color material in each ink, for example, when used for inkjet recording, is selected so that the ink has excellent ejection characteristics and appropriately selected to have a desired color tone and density. good. As a standard in this case, for example, it is preferable that the content of the coloring material is in a range of about 1 to 50% by mass with respect to the total mass of the ink. The amount of water contained in the ink is preferably in the range of 50 to 95% by mass with respect to the total mass of the ink.

[Ink characteristics]
(Inkjet ejection characteristics, permeability to recording media)
The ink set used in the present invention is suitable as an ink set for inkjet recording. Examples of the ink jet recording method include a recording method in which mechanical energy is applied to ink to eject droplets, and a recording method in which thermal energy is applied to ink and ink droplets are ejected by foaming of the ink. The ink is particularly suitable for these recording methods. The ink in the present invention has a characteristic that it can be ejected from a recording head of an inkjet recording apparatus. As the characteristics of the liquid ink, for example, the viscosity is preferably 1 to 15 cps and the surface tension is preferably 40 mN / m (dyne / cm) or less. Moreover, it is preferable that Ka value by Bristow method is 1 ml * m-2 * msec-1 / 2 or more. In particular, it is preferable that the viscosity is 1 to 5 cps, the surface tension is 25 to 35 mN / m (dyne / cm), and the Ka value is 1 to 5 ml · m−2 · msec−1 / 2.

  Examples of the present invention will be specifically described below using comparative examples. The present invention is not limited by the following examples without departing from the gist thereof. In the following description, “parts” or “%” are based on mass unless otherwise specified.

[Preparation of pigment ink]
(Black ink adjustment)
10 parts of a pigment (carbon black), 120 parts of an anionic polymer, and 70 parts of pure water were mixed. Here, the carbon black was “product name: Mogul L, manufactured by Cablack”. The anionic polymer P-1 was “styrene-acrylic acid copolymer, acid value 200, weight average molecular weight 10,000, aqueous solution having a solid content of 10%, neutralizer: potassium hydroxide”.
Then, the materials shown below were charged into a batch type vertical sand mill (manufactured by IMEX), filled with 150 parts of 0.3 mm diameter zirconia beads, and dispersed for 5 hours while cooling with water. After the dispersion was centrifuged to remove coarse particles, a pigment dispersion “Bk” having a solid content of about 12% and a weight average particle size of 120 nm was obtained in the final preparation.

(Black ink composition)
-Pigment dispersion Bk 30 parts-Glycerol 9 parts-Diethylene glycol 6 parts-Acetylene glycol ethylene oxide adduct (trade name: acetylenol EH) 1 part-Water 54 parts The pH of the black ink thus obtained was 7.9. .

(Preparation of cyan ink)
These were mixed with 10 parts of pigment (CI Pigment Blue 15: 3), 20 parts of anionic polymer P-1 and 70 parts of pure water. Here, the above C.I. I. Pigment Blue 15: 3 was “product name: Fastgen Blue FGF, manufactured by Dainippon Ink and Chemicals, Inc.”. The anionic polymer P-1 was “styrene-acrylic acid copolymer, acid value 200, weight average molecular weight 10,000, aqueous solution having a solid content of 10%, neutralizer: potassium hydroxide”. These were charged into a batch type vertical sand mill (manufactured by IMEX), filled with 150 parts of 0.3 mm diameter zirconia beads, and dispersed for 5 hours while cooling with water. After the dispersion was centrifuged to remove coarse particles, a pigment dispersion “C” having a solid content of about 12% and a weight average particle size of 100 nm was obtained.

(Composition of cyan ink)
-Pigment dispersion C 30 parts-Glycerol 9 parts-Diethylene glycol 6 parts-Acetylene glycol ethylene oxide adduct (trade name: acetylenol EH) 1 part-Water 54 parts The pH of the cyan ink thus obtained was 8.0. It was.

(Preparation of magenta ink)
The pigment (CI Pigment Red 122) was 10 parts, the anionic polymer P-1 was 20 parts, pure water was 70 parts, and these were mixed. Here, the above C.I. I. Pigment Red 122 was “Dainippon Ink Chemical Co., Ltd.”. The anionic polymer P-1 was “styrene-acrylic acid copolymer, acid value 200, weight average molecular weight 10,000, aqueous solution having a solid content of 10%, neutralizer: potassium hydroxide”. Then, these materials were charged into a batch type vertical sand mill (manufactured by IMEX), filled with 150 parts of 0.3 mm diameter zirconia beads, and dispersed for 5 hours while cooling with water. After the dispersion was centrifuged to remove coarse particles, a pigment dispersion “M” having a solid content of about 12% and a weight average particle size of 150 nm in the final preparation was obtained.

(Magenta ink composition)
-Pigment dispersion M 30 parts-Glycerol 9 parts-Diethylene glycol 6 parts-Acetylene glycol ethylene oxide adduct (trade name: acetylenol EH) 1 part-Water 54 parts The magenta ink thus obtained had a pH of 7.8. It was.

(Preparation of yellow ink)
10 parts of the pigment (CI Pigment Yellow 180), 20 parts of the anionic polymer P-1 and 70 parts of pure water were mixed. Here, the above C.I. I. Pigment Yellow 180 was “product name: Nova Palm Yellow PH-G, manufactured by Hoechst”. The anionic polymer P-1 was “styrene-acrylic acid copolymer, acid value 200, weight average molecular weight 10,000, aqueous solution having a solid content of 10%, neutralizer: potassium hydroxide”. These materials were charged into a batch type vertical sand mill (manufactured by IMEX), filled with 150 parts of 0.3 mm diameter zirconia beads, and dispersed for 5 hours while cooling with water. After this dispersion was centrifuged to remove coarse particles, a pigment dispersion “Y” having a solid content of about 12% and a weight average particle size of 125 nm in the final preparation was obtained.

(Composition of yellow ink)
-Pigment dispersion Y 30 parts-Glycerol 9 parts-Diethylene glycol 6 parts-Acetylene glycol ethylene oxide adduct (trade name: acetylenol EH) 1 part-Water 54 parts The pH of the yellow ink thus obtained was 8.1. It was.
Therefore, the cyan ink, magenta ink, and yellow ink are set as a pigment ink set.

[Method for determining good and poor solvents of water-soluble organic solvent used, and method for determining low-volatile solvents]
In order to select a good solvent and a poor solvent for the pigment in the pigment dispersion, or the pigment and the dispersant, and to determine a low volatility solvent, the following experiment was conducted.
First, the pigment inks Bk, C, M, and Y were dropped into the solvent shown in Table 1 filled with a petri dish, and the degree of diffusion of the pigment in the solvent after standing for 1 day was observed.
(Judgment method)
・ Pigment was diffusing in the solvent: ○
-Pigment is not diffusing in the solvent: ×

表１より、本発明に好適な水溶性有機溶剤は、グリセリン、エチレングリコール、ジエチレングリコール、トリメチロールプロパンが挙げられる。勿論、これらに限定されるものではない。 Table 1 shows the determination results.

From Table 1, examples of water-soluble organic solvents suitable for the present invention include glycerin, ethylene glycol, diethylene glycol, and trimethylolpropane. Of course, it is not limited to these.

[Clear ink adjustment]
The components shown in Table 2 were mixed, sufficiently stirred and dissolved, and then subjected to pressure filtration with a microfilter having a pore size of 0.2 μm (manufactured by Fuji Film) to prepare a clear ink. The pH was adjusted by adding sodium hydroxide or acetic acid.
Table 2 shows the components of each clear ink.

インクジェット記録装置として、オンデマンド型マルチ記録ヘッドを有する「キヤノン製ＢＪＦ９００」の改造機を用いた。このインクジェット記録装置の記録ヘッドに、上記実施例及び上記比較例に示したようなインクセットを搭載した。そして、記録信号に応じた熱エネルギーをインクに付与することにより記録ヘッドからインクを吐出させ、その結果に基づいて以下の評価を行った。 Ink sets were prepared with the combinations shown in Table 3 and used as examples and comparative examples.

A modified Canon BJF900 having an on-demand multi-recording head was used as the ink jet recording apparatus. Ink sets as shown in the above examples and comparative examples were mounted on the recording head of this ink jet recording apparatus. The ink was ejected from the recording head by applying thermal energy corresponding to the recording signal to the ink, and the following evaluation was performed based on the result.

〔Evaluation methods〕
(Evaluation 1: Absorbability of pigment ink in ink absorber)
In the environment of a temperature of 30 ° C. and a humidity of 10%, the ink of the ink set was simultaneously and integrally sucked using the cap (see FIG. 5). This was repeated 10 times at 10 minute intervals, and the ink absorber (see FIG. 5) after being left for 1 day was observed. This was evaluated according to the following evaluation criteria.
(Double-circle): A pigment deposit is not seen in an ink absorber.
○: Almost no pigment deposit is observed on the ink absorber.
X: Lumps of pigment deposits are seen on the ink absorber.

(Evaluation 2: Re-solubility of pigment fixed matter in ink absorber)
An ink absorber on which pigment ink was fixedly deposited in advance was attached to the cap of BJF900. Then, clear ink was preliminarily ejected onto the ink absorber, and the recording head was capped with the clear ink filled in the ink absorber. Therefore, the ink absorber was left for 1 hour, and then the ink absorber was sucked idle. This empty suction was performed by sucking ink in the cap with a suction pump with the cap open. The state of the ink absorber after the above cycle was repeated 5 times was observed.
This was evaluated according to the following evaluation criteria.
(Double-circle): A pigment deposit is not seen in an ink absorber.
○: Almost no pigment deposit is observed on the ink absorber.
X: Lumps of pigment deposits are seen on the ink absorber.

Table 4 shows the results of the evaluation.

The embodiment described above relates to a maintenance method for an ink jet recording apparatus that performs recording by discharging ink from a recording head to a recording medium. Then, an ink set including at least one pigment ink and a clear ink containing at least one water-soluble organic solvent that is a good solvent for the pigment ink is mounted on the recording head. Also, the pigment ink ejection port and the clear ink ejection port of the recording head are capped with the same cap. Therefore, the suction means connected to the cap simultaneously sucks the pigment ink from the pigment ink discharge port and the clear ink from the clear ink discharge port.
According to this embodiment, when using the pigment ink, a reliable and stable suction recovery operation can be maintained over a long period of time. Further, by reducing ink stains on the ink absorber due to suction recovery, inconveniences such as ink stains and ink color mixing at the discharge ports can be reduced.

  In the above embodiment, the serial type ink jet recording apparatus that performs recording with the recording head mounted on the carriage that moves along the recording medium has been described as an example. The present invention can be similarly applied to a line-type ink jet recording apparatus that performs recording only by sub-scanning using a recording head for full line recording or the like, and has the same effects. In addition, the present invention can be similarly applied to any inkjet recording apparatus regardless of the number of recording heads, the number of ink types to be used, the properties, and the like, and has the same effects. . In addition, the present invention can be widely applied not only as a single device such as a printer, a copier, a facsimile machine, and a captured image forming apparatus, but also as a recording device in a composite device combining them or a composite device such as a computer system. The effect of this is achieved.

1 is a perspective view of an ink jet recording apparatus suitable for carrying out a maintenance method of the present invention. FIG. 2 is a perspective view of a recording head of the ink jet recording apparatus of FIG. 1. FIG. 3 is a front view showing an array of ejection openings on the ejection surface of the recording head in FIG. 2. It is a perspective view which shows the suction recovery mechanism of the recovery mechanism part suitable for implementing the maintenance method of this invention. It is a longitudinal cross-sectional view of the cap in FIG. It is a longitudinal cross-sectional view which shows the wiping mechanism of the recovery mechanism part in FIG. It is a perspective view which shows another structural example of the recording head of the inkjet recording device of FIG.

Explanation of symbols

21 Ink ejection part (recording head)
22 Ink storage section 24 Liquid chamber 31 Discharge surface (recording head)
33 Discharge port array 35 Discharge port 41 Cap rubber 42 Cap cover 43 Lip part (sealing part)
44 Suction hole 47 Suction tube 48 Ink absorber 49 Waste ink tube 101 Carriage 102 Guide shaft 103 Chassis 105 Transport roller 106 Platen 107 Recording head 112 Paper discharge roller 115 Paper feed section 120 Recovery mechanism section 121 Cap 122 Suction pump (negative pressure generation) means)
123 Wiper 125 Cap holder 126 Waste ink collection unit 127 Ink absorber 131 Wiper holder 132 Guide 133, 135 Rack gear 136 Double gear

Claims (7)

A maintenance method for an ink jet recording apparatus that performs recording by discharging ink from a recording head to a recording medium,
An ink set comprising at least one pigment ink and a clear ink containing at least one water-soluble organic solvent that is a good solvent for the pigment ink is mounted on the recording head.
Capping the discharge port of the pigment ink and the discharge port of the clear ink of the recording head with the same cap,
A maintenance method for an ink jet recording apparatus, wherein suction of pigment ink from the discharge port of the pigment ink and suction of clear ink from the discharge port of the clear ink are simultaneously performed by suction means connected to the cap.   2. The maintenance method for an ink jet recording apparatus according to claim 1, wherein an ink absorber is disposed inside the cap.   The maintenance method for an ink jet recording apparatus according to claim 1, wherein at least one of the good solvents is a low volatility solvent.   The maintenance method for an ink jet recording apparatus according to claim 1, wherein the pigment of the pigment ink is an alkali-soluble pigment.   The maintenance method for an ink jet recording apparatus according to claim 1, wherein a pH of the clear ink is higher than a pH of the pigment ink.   6. The maintenance method for an ink jet recording apparatus according to claim 1, wherein the clear ink is preliminarily ejected to the cap after the pigment ink is preliminarily ejected to the cap. The ink jet recording apparatus maintenance method according to claim 1, wherein after the pigment ink and the clear ink are sucked, the clear ink is preliminarily ejected to the cap.

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