JP2005103895A - Ink jet recorder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ink jet recorder in which cleaning is performed using such a cleaning liquid as clogging does not take place even if ink dispersed with colored fine particles composed of a coloring material and a polymer is used and clogging can be reset easily. <P>SOLUTION: In an ink jet recorder comprising a mechanism for cleaning a recording head using a cleaning liquid dispersed with colored fine particles composed of a coloring material and a polymer, the recording head is cleaned using such a cleaning liquid as the volume mean particle size of a mixture liquid (25°C) produced by mixing ink and cleaning liquid at a mass ratio of 1:1 is 1.2 times or more of the mean particle size of ink. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an ink jet recording apparatus that uses an ink in which colored fine particles composed of a color material and a polymer are dispersed, and has excellent recording head cleaning properties.

  Colored fine particle inks composed of a color material and a polymer have been proposed as inks that achieve both image storability and color tone (see Patent Documents 1 to 7). However, since the colored fine particle ink contains a large amount of the polymer component, the viscosity of the remaining component tends to increase after the low boiling point solvent volatilizes, and sometimes solidifies completely. When such thickening and solidification occurs at the meniscus of the nozzle due to the volatilization of the solvent, it becomes difficult to suck the ink due to negative pressure, and it becomes impossible to eliminate nozzle clogging. In particular, when the recording apparatus is used in a low humidity environment, or when the ink ejection frequency is low and the time until the next emission is long, such a phenomenon is likely to occur. By cleaning the head using the cleaning liquid as shown in the claims, it has become possible to quickly remove the thickener and solid matter adhering to the nozzle and the nozzle surface.

  For example, JP-A-11-152499 uses a cleaning liquid, and JP-A-10-151759, JP-A-2002-347256, JP-A-2003-191480 and the like use these cleaning liquids to clean the head. A cleaning liquid supply mechanism is disclosed.

  Further, in a printer using pigment ink, there is a cleaning method for cleaning a recording head by introducing a cleaning liquid under a negative pressure inside a cap with a head cleaning liquid containing a surfactant, a basic compound, water, and the like. It is disclosed (see Patent Document 8).

  However, since these cleaning liquids are for pigment inks, solidified inks (including polymerizing), etc., or have different cleaning effects depending on the type of ink, they can be applied as they are when the ink composition changes. It was not a thing.

For example, a colored fine particle ink in which fine particles composed of a colorant and a polymer are dispersed in a liquid, specifically, an ink in which fine particles impregnated with a pigment in a polymer are dispersed in the liquid, and a dye is compatible with the polymer. In a recording apparatus using a type of ink in which the ratio of polymer to color material is higher than that of pigment ink, such as ink in which fine particles are dispersed in the liquid, it is difficult to apply the conventional cleaning liquid and cleaning method. Was the current situation.
JP 55-139471 A JP 55-45272 A Japanese Patent Laid-Open No. 3-250069 JP-A-8-253720 JP-A-8-92513 JP-A-8-183920 JP 2001-11347 A JP 2000-127419 A

  Ink jet recording apparatus using an ink in which colored fine particles composed of a coloring material and a polymer are dispersed. Ink jet recording apparatus that performs cleaning using a cleaning liquid that is not clogged and that can be easily restored when clogged. Is to provide.

The above object of the present invention is achieved by the following means.
(Claim 1)
In an ink jet recording apparatus using an ink in which colored fine particles composed of a color material and a polymer are dispersed and having a cleaning mechanism for cleaning a recording head with a cleaning liquid, the mass ratio of the ink and the cleaning liquid is 1: 1. The recording head is cleaned using a cleaning liquid in which the volume average particle diameter of the mixed liquid (25 ° C.) when mixed in step 1 is 1.2 times or more the average particle diameter of the ink alone. An ink jet recording apparatus.
(Claim 2)
A cleaning liquid in which the volume average particle diameter of the mixed liquid (25 ° C.) when the ink and the cleaning liquid are mixed at a mass ratio of 1: 1 is 1.4 times or more than the average particle diameter of the ink alone. The ink jet recording apparatus according to claim 1, wherein the ink jet recording apparatus is used.
(Claim 3)
In an ink jet recording apparatus having a cleaning mechanism for cleaning a recording head using a cleaning liquid using ink in which colored fine particles composed of a color material and a polymer are dispersed, the ink and the cleaning liquid are mixed at a mass ratio of 1: 1. Mix and leave for 7 days in an environment of 60 ° C. After mixing the ink and the cleaning liquid, the absorbance after mixing the ink and the cleaning liquid measured by the absorbance measurement method shown below is compared with the ink absorbance. An ink jet recording apparatus, wherein the head is cleaned using a cleaning liquid having an absorbance of 35% or less compared to the absorbance of the ink before mixing.

Absorbance measurement method: The ink and the cleaning liquid were mixed at a mass ratio of 1: 1, and the supernatant of 10% by mass of the upper part of the liquid that was allowed to stand in an environment of 60 ° C. for 7 days was measured and diluted with pure water to 350- Spectral absorption is measured in the range of 800 nm (25 ° C.), and the absorbance at the maximum absorption wavelength is multiplied by the dilution factor.
(Claim 4)
The inkjet according to claim 3, wherein a cleaning liquid is used such that when the absorbance before and after mixing is measured by the absorbance measurement method, the absorbance after mixing is 25% or less compared to before mixing. Recording device.
(Claim 5)
In an ink jet recording apparatus having a cleaning mechanism for cleaning a recording head using a cleaning liquid, using ink in which colored fine particles composed of an oil-soluble dye and a polymer are dispersed, the values of A and B defined below are as follows: An inkjet recording apparatus using a cleaning liquid that satisfies a relationship represented by the following formula.

  A: Absorbance calculated by diluting the ink used in the recording apparatus with pure water, measuring the spectral absorption in the range of 350 nm to 800 nm (25 ° C.), and multiplying the measured value at the maximum absorption wavelength by the dilution rate.

B: Absorbance calculated by diluting the ink used in the recording apparatus with a cleaning liquid, measuring spectral absorption in the range of 350 nm to 800 nm (25 ° C.), and multiplying the measured value at the maximum absorption wavelength by the dilution rate.
(Claim 6)
Measures the absorbance of ink in the range of 350 nm to 800 nm in an ink jet recording apparatus equipped with a cleaning mechanism for cleaning a recording head using a cleaning liquid, using ink in which colored fine particles composed of an oil-soluble dye and a polymer are dispersed. An ink jet recording apparatus comprising: a cleaning liquid having a different number of spectral peaks depending on whether the measurement dilution solvent is pure water or the cleaning liquid.

  According to the present invention, an ink jet recording apparatus excellent in cleaning performance of a recording head nozzle can be obtained even when an ink in which colored fine particles composed of a color material and a polymer are dispersed is used.

  The best mode for carrying out the present invention will be described in detail below, but the present invention is not limited thereto.

  The colored fine particle ink in the present invention refers to an ink in which fine particles are composed of a polymer and a color material and are dispersed in a liquid. Specifically, an ink in which fine particles in which a pigment is impregnated in a polymer is dispersed in a liquid, an ink in which fine particles in which a dye is compatible with a polymer are dispersed in a liquid, and the like are included.

  Conventional pigment inks that are well known so far may contain a polymer compound as a dispersant. However, in the colored fine particle ink, the fine particles are composed of a polymer and a color material, and the ratio of the polymer to the color material tends to be larger than that of a general pigment ink. Specifically, the pigment ink dispersed with the polymer dispersant has a polymer ratio to the colorant of 0.2: 1 to 0.3: 1, whereas the colored fine particle ink has a ratio of 0.5: 1. Often in the range of ˜3: 1.

  For this reason, in the colored fine particle ink, the film forming action of the polymer tends to work more strongly than the normal ink. In such a head that ejects ink, if ink droplets adhere to the periphery of the nozzle opening and are dried, it becomes difficult to form a film and remove it. This causes the ink to be obliquely emitted or missing. In addition, since the polymer component is large, the viscosity of the remaining component after the low boiling point solvent is volatilized tends to increase, and sometimes it is completely solidified by the film forming action of the polymer. In the meniscus of the nozzle, when such thickening and solidification due to the volatilization of the solvent occurs, it becomes difficult to suck the ink by the negative pressure, and the clogging of the nozzle cannot be eliminated. In particular, when the recording device is used in a low humidity environment, or when the ink ejection frequency is low and the time until the next ejection is long, such a phenomenon is likely to occur, and maintenance is performed so that there is no clogging at all times. As compared with ordinary dye inks and pigment inks, it has become a larger problem.

  The ink jet apparatus according to the present invention cleans the recording head nozzle surface or nozzle (ink discharge port) with a cleaning liquid in addition to normal maintenance using an ink moisturizing cap, suction cap, wiper blade, or the like. Ink jet recording apparatus provided with a cleaning mechanism.

  First, the cleaning liquid of the present invention will be described.

  In the present invention, an excellent cleaning effect can be exhibited by using the cleaning liquid having the structure described in claims 1 to 4.

  That is, in the configuration according to claims 1 and 2, a mixed liquid (25 ° C.) obtained by mixing an ink in which colored fine particles composed of a colorant and a polymer are dispersed and a cleaning liquid in a mass ratio of 1: 1. The cleaning liquid has an excellent cleaning effect by using a cleaning liquid whose volume average particle diameter is 1.2 times or more, preferably 1.4 times or more, compared with the average particle diameter of the ink alone. I can do it. The upper limit is not uniquely determined depending on the configuration of the colored fine particles, production conditions, and the like, but is practically a numerical value of 200 times or less, preferably 100 times or less due to aggregation.

  The volume average particle size of the colored fine particles can be determined by a commercially available particle size measuring device using a light scattering method, an electrophoresis method, a laser Doppler method, etc. As a specific particle size measuring device, for example, Examples thereof include a laser diffraction particle size measuring device SLAD1100 manufactured by Shimadzu Corporation, a particle size measuring device (HORIBA LA-920), a Malvern Zetasizer 1000HS, and the like.

  According to the third and fourth aspects of the present invention, the ink in which the colored fine particles composed of the colorant and the polymer are dispersed and the cleaning liquid are mixed at a mass ratio of 1: 1, and the mixture is placed in an environment of 60 ° C. for 7 days When the absorbance after mixing the ink and cleaning liquid measured by the absorbance measurement method shown below is compared with the absorbance of the ink before mixing, the absorbance after mixing the ink and cleaning liquid is An excellent cleaning effect can be obtained by using a cleaning liquid that is 35% or less, preferably 25% or less compared to the absorbance of the ink. The lower limit is 0% where the ink settles practically.

  Absorbance measurement method: The ink and the cleaning liquid were mixed at a mass ratio of 1: 1, and the supernatant of 10% by mass of the upper part of the liquid that was allowed to stand in an environment of 60 ° C. for 7 days was measured and diluted with pure water to 350- Spectral absorption is measured in the range of 800 nm (25 ° C.), and the absorbance at the maximum absorption wavelength is multiplied by the dilution factor.

  For the spectral absorption measurement method, the dilution rate is adjusted so that the absorbance measurement value at the maximum absorption wavelength falls within the range of 0.5 or more and less than 2, considering the measurement accuracy of the spectrometer. taking measurement.

  The reason why the cleaning liquid of the present invention exhibits an excellent cleaning effect by the above configuration is not limited to this, but is considered to be due to the following mechanism.

  That is, due to such mixing of the ink and the cleaning liquid, the dispersed colored fine particles are aggregated. Such a cleaning liquid is considered to have an effect of dissolving or swelling the polymer of colored fine particles. The cleaning liquid is considered to have an excellent cleaning property because it exhibits an effect of dissolving and swelling an ink residue mainly composed of a polymer after solvent volatilization.

Further, the cleaning liquid according to claim 5, that is, the ink is diluted with pure water, the spectral absorption is measured in the range of 350 nm to 800 nm (25 ° C.), and the measured value at the maximum absorption wavelength is multiplied by the dilution rate. The calculated absorbance (A), and the ink was diluted with a cleaning liquid, the spectral absorption was measured in the range of 350 nm to 800 nm (25 ° C.), and the absorbance calculated by multiplying the measured value at the maximum absorption wavelength by the dilution rate ( B), the following formula | B−A / A | ≧ 0.5
An excellent cleaning effect can be obtained by using a cleaning liquid that satisfies the relationship represented by the above, or by using a cleaning liquid that has a different number of spectral peaks between pure water dilution and cleaning liquid dilution. This is thought to be due to the following reasons.

Usually, with respect to the spectral absorption measurement, the absorbance is often higher when measured in a dissolved state than when the color material is measured in a dispersed state. However, although it is exceptional, there are cases in which some color materials are associated in a dispersed state, exhibit a spectrum shape different from the dissolved state, change the number of peaks, or exhibit a lower absorbance in the dissolved state.
Accordingly, when the colored fine particle ink is diluted with the cleaning liquid as in the constitutions of claims 5 and 6, when the absorbance clearly changes compared with the case of dilution with pure water, or the number of peaks, that is, the spectral shape changes. In this case, it is assumed that the cleaning liquid has an effect of dissolving the coloring material and the polymer. Such a cleaning liquid is considered to exhibit excellent cleaning properties as in the above-described inference.

  In the spectral absorption measurement method, as described above, the dilution ratio is set so that the absorbance measurement value at the maximum absorption wavelength falls within the range of 0.5 or more and less than 2, in consideration of the measurement accuracy of the spectrometer. It shall be adjusted and measured.

  The constituent materials used for the cleaning liquid according to the present invention will be described below.

  The water that is one of the components used in the cleaning liquid in the present invention is preferably purified to some extent. For example, ultrapure water, pure water, ion exchange water, distilled water, etc. Sonicated water, magnetized water, electrolytic water, ionized water, or the like can be used. Moreover, you may use the water which deaerated gas, such as dissolved oxygen which exists in water.

  These purified water can be obtained by a conventionally known method. For example, after using tap water or well water as raw water and performing pretreatment such as activated carbon adsorption treatment to remove coarse particles, reverse osmosis membrane treatment to remove fine particles, and removing dissolved ions Ion exchange treatment for removing the fine particles generated in the treatment process, ion exchange treatment for further removing ionic substances and increasing the degree of purification, ultraviolet irradiation treatment for sterilization, etc. in order, Ultra-pure water can be obtained by performing a final filtration treatment.

  Other constituent materials of the cleaning liquid of the present invention include organic solvents, surfactants, basic compounds and the like, and antiseptics, antifungal agents and the like may be added as necessary. Specific examples of the organic solvent include monohydric alcohols such as methanol, ethanol, propanol, and butanol, ethylene glycol, diethylene glycol, triethylene glycol, glycerin, 1,2-hexanediol, and 1,6-hexanediol. And polyhydric alcohol ethers such as dihydric alcohols, diethylene glycol monobutyl ether and triethylene glycol monobutyl ether, and alkanolamines such as ethanolamine, diethanolamine and triethanolamine.

  Surfactants that can be used in the present invention include anionic, cationic, amphoteric surfactants and / or nonionic surfactants.

  Examples of the anionic surfactant include alkyl sulfocarboxylates, α-olefin sulfonates, polyoxyethylene alkyl ether acetates, N-acyl amino acids and salts thereof, N-acyl methyl taurates, alkyl sulfates. Polyoxyalkyl ether sulfate, alkyl sulfate polyoxyalkyl ether phosphate, rosin acid soap, castor oil sulfate ester, lauryl alcohol sulfate ester, alkylphenol type phosphate ester, alkyl type phosphate ester, alkylaryl sulfonate, diethyl Examples include sulfosuccinate, diethylhexyl sulfosuccinate, dioctyl sulfosuccinate, 2-vinylpyridine derivatives, poly-4-vinylpyridine derivatives, and the like.

  Examples of amphoteric surfactants include lauryldimethylaminoacetic acid betaine, 2-alkyl-N-carboxymethyl-N-hydroxyethylimidazolinium betaine, coconut oil fatty acid amidopropyldimethylaminoacetic acid betaine, polyoctylpolyaminoethylglycine, and others Examples include imidazoline derivatives.

  Furthermore, nonionic surfactants can also be used in the cleaning liquid according to the present invention. Examples of the nonionic surfactant include polyoxyethylene nonyl phenyl ether, polyoxyethylene dodecyl phenyl ether, polyoxyethylene alkyl aryl ether, polyoxyethylene oleyl ether, polyoxyethylene lauryl ether, polyoxyethylene alkyl ether, Ether type such as polyoxyalkylene alkyl ether, polyoxyethylene oleate, polyoxyethylene distearate, sorbitan laurate, sorbitan monostearate, sorbitan monooleate, sorbitan sesquioleate, polyoxyethylene monooleate, poly Esters such as oxyethylene stearate or acetylene glycol surfactants such as 2,4,7,9-teto Methyl-5-decyne-4,7-diol, 3,6-dimethyl-4-octyne-3,6-diol, 3,5-dimethyl-1-hexyn-3-ol (for example, Nisshin Chemical Co., Ltd.) Surfynol 104, 82, 465, 485, TG, etc.).

  The cleaning liquid according to the present invention can contain the surfactant in an arbitrary amount within the scope of the present invention, but the addition amount is preferably 20% by mass or less, more preferably with respect to the total mass of the cleaning liquid. It can contain in the range of 0.1-10 mass%.

  Moreover, as a specific example of a basic compound, it can be an inorganic or organic basic compound. Preferable examples of the inorganic base compound include hydroxides of alkali metals (for example, lithium, sodium, potassium, etc.), and sodium hydroxide and potassium hydroxide are particularly preferable.

  Examples of organic basic compounds include mono-, di- or tri-lower alkylamines, mono-, di- or tri-lower alkanolamines, cyclic amines or diamines. Here, carbon number of a lower alkyl part or a lower alkanol part becomes like this. Preferably it is 1-6, More preferably, it is 1-4. Moreover, the lower alkyl part and the lower alkanol part of the di-substituted product or the tri-substituted product may be the same or different from each other.

  Examples of mono-, di- or tri-lower alkylamines include mono-, di- or tri-methylamine, mono-, di- or tri-ethylamine, mono-, di- or tri-tert-butylamine. be able to. Examples of mono-, di- or tri-lower alkanolamines include mono-, di- or tri-methanolamine, mono-, di- or tri-ethanolamine.

  Examples of the cyclic amine include piperidine or pyrrolidine, and examples of the diamine include ethylene diamine or trimethylene diamine. As the organic basic compound, tri-ethanolamine, piperidine, or ethylenediamine is preferably used. The above inorganic or organic basic compounds can be used alone or in any combination.

  The cleaning liquid according to the present invention can contain the above basic compound in an arbitrary amount within the scope of the object of the present invention. In the case of an inorganic basic compound, the addition amount is the total mass of the cleaning liquid. Is preferably 0.01 to 5% by mass, more preferably 0.1 to 2% by mass. In particular, when the inorganic base compound is an alkali metal hydroxide, the addition amount is 0.01 to 2.5% by mass, more preferably 0.1 to 1% by mass with respect to the total mass of the cleaning liquid. is there.

  In the case of an organic base compound, the addition amount is preferably 0.1 to 30% by mass, more preferably 0.3 to 20% by mass with respect to the total mass of the cleaning liquid. If the addition amount of the basic compound is too small, the original effect of the present invention may not be sufficiently exhibited. Conversely, if the addition amount is too large, the pH of the cleaning liquid becomes too high. This may adversely affect the recording head member and the cleaning liquid supply system.

  The cleaning liquid according to the present invention can be obtained by adjusting the type and amount of these materials.

  The cleaning liquid may be used in any form as long as it improves the cleaning efficiency of the nozzle surface. For example, the cleaning liquid is sprayed around the nozzle (described in JP-A-10-151759), the nozzle A mode in which the cleaning liquid is sprayed on a wiper blade that sweeps the ink, and a mode in which the cleaning liquid is introduced in the process of sucking ink by setting the nozzle to a negative pressure (described in Japanese Patent Laid-Open No. 2003-191480) are conceivable. If the cleaning liquid is introduced at the time of negative pressure suction, the cleaning liquid can be used by lowering the cleaning liquid viscosity than the ink viscosity or by making the cleaning liquid supply port area larger than the ink discharge port. Is more easily sucked out than ink, and the cleaning effect of the cleaning liquid can be further utilized. It is also preferable that the cleaning liquid supply unit and the negative pressure generating unit be separated as much as possible so that the cleaning liquid is spread over the entire nozzle surface.

  Hereinafter, the ink jet recording apparatus of the present invention will be described in more detail.

  FIG. 1 is a schematic diagram illustrating an example of a main configuration of an ink jet recording apparatus. The ink jet recording apparatus 1 performs printing by ejecting ink onto a recording paper. As a main configuration of a portion that performs the printing, as shown in FIG. (Not shown), a recording head 3 that ejects ink onto the recording paper 2, a carriage 4 that stores the recording heads 3 for each of a plurality of colors, and a suction cap 16 and a wiper blade 17 that perform maintenance of the recording head 3. A maintenance unit 5, a guide rail 6 that guides the carriage 4 along the horizontal direction (arrow A) during printing or maintenance, and a home position 7 having a moisturizing cap 8 that serves as a waiting place for the carriage 4; And a control unit (not shown) for controlling these units. C is an ink cartridge, and each ink sent from the ink cartridge C is once stored in the sub-tank T and then sent to the recording head through the supply valve V and the ink supply path P.

  The recording paper conveying means conveys the recording paper 2 on the printing area 9 in synchronization with the operation of the carriage 4 during printing, and the recording paper 2 moves downward (arrows) from the printing area when printing is completed. B) is conveyed.

  FIG. 2 is a schematic diagram showing the configuration of the recording head. The recording head 3 is connected to a head substrate 10 with an ink discharge main body 11 for discharging ink, a temperature sensor (temperature measuring means) 12 for measuring temperature in the vicinity of the ink discharge main body 11, and a flexible cable. A flexible cable connecting portion 13 for inputting / outputting signals to / from the discharge portion main body portion 11 and the temperature sensor 12 is installed. The ink discharge main body 11 is provided with a plurality of discharge ports 14 for discharging ink along the center line of the surface (nozzle surface 15) facing the recording paper 2. It communicates with a nozzle (flow path).

  The recording head 3 is installed on the carriage 4 in a state where one end of the nozzle surface 15 is inclined so as to be lower than the other end.

  The temperature sensor 12 measures the temperature in the vicinity of the ink discharge main body 11 or the temperature of the head substrate 10, and is electrically connected to the control unit through the flexible cable connection unit 13.

  As shown in FIG. 2, the carriage 4 is provided with a plurality of recording heads 3 for each color (yellow, magenta, cyan, black).

  The maintenance unit 5 covers the discharge port, sucks ink from the discharge port 14, and sucks ink from the discharge port 14. After the ink is sucked by the suction cap 16, the ink remaining on the nozzle surface 15 is maintained. A wiper blade 17 for wiping off, and a blade cleaner unit for cleaning the wiper blade (not shown in FIG. 2) are provided.

  A plurality of (two in this embodiment) suction caps 16 are provided side by side, and a plurality of recording heads 3 can be sucked at a time during maintenance.

(Embodiment 1)
FIG. 3 is a diagram schematically illustrating a configuration for recovering ejection according to the first embodiment. In the drawing, in the present embodiment, the maintenance unit is provided with a sprayer 21 for spraying the cleaning liquid according to the present invention on the nozzle surface of the ink discharge main body of the recording head 3. Reference numeral 23 denotes a cleaning liquid tank for storing the cleaning liquid. The cleaning liquid stored in the cleaning liquid tank 23 is supplied to the sprayer 21 by the pump 27 through the supply pipe 25. By spraying the cleaning liquid onto the nozzle surface of the recording head with the sprayer 21, the fixed matter on the nozzle surface can be efficiently removed. The tank, pump, and sprayer shown above are provided in the maintenance unit in this embodiment. However, if the cleaning liquid can be reliably supplied to the nozzle surface, the positions provided are the main body side and the head side. Any of (carriage side) may be used.

  The recording head 3 sprayed with the cleaning liquid moves to the left in the figure. For example, in this case, the nozzle surfaces are sequentially wiped by the two wiper blades 31 and 32, and the fixed matter and the cleaning liquid are removed. . In addition, as a material of the wiper blades 31 and 32, for example, a flexible material such as an ether-bonded urethane having a thickness of 0.7 mm is used. Alternatively, the cleaning liquid may be sprayed after wiping the nozzle surface first. In this case, the adhered matter is often thinly stretched on the nozzle surface and remains in the form of spots, but on the other hand, further cleaning liquid is sprayed, and then further wiping is performed to improve the thinly adhered matter. Can be removed. Further, the number of wiper blades may be any number, and the nozzle surface of the head may be rubbed with a wiping member using an absorber or a porous body instead of the wiper.

  With the configuration as described above, the cleaning liquid is reliably applied to the nozzle surface, and therefore, the adhered reactant can be easily removed.

(Embodiment 2)
FIG. 4 is a diagram schematically showing a configuration for removing a fixed object according to the second embodiment of the present invention. In this embodiment, a cleaning liquid is supplied at the time of capping by a suction cap. .

  In the figure, 16 is a suction cap that covers the nozzle surface of the recording head 2, and 37 is a pump for sucking the cleaning liquid and ink in the suction cap 16 through the discharge pipe 36. Waste liquid such as cleaning liquid discharged from the liquid is stored in a waste liquid reservoir 39. In the present embodiment, at the time of capping, the suction cap 16 is filled with the cleaning liquid by the pump 27 for supplying the cleaning liquid, and the nozzle surface of the recording head 3 is immersed in the cleaning liquid. Thereby, the adhering matter adhering to the nozzle surface is easily removed by subsequent wiping or the like. Then, the cleaning liquid filled in the suction cap 16 is discharged by the pump 37. The cap, pump, waste liquid discharge pipe, and waste liquid reservoir used at this time can also be those used in the suction process performed as part of the discharge recovery process in the normal cleaning unit.

  According to the present embodiment, not only the fixed matter is dissolved, but also the nozzle surface can be cleaned at the same time, and there is an effect of further purifying the nozzle surface. Further, the fixed matter can be effectively removed even for a head having a shape that is difficult to wipe as a cleaning effect of the cleaning liquid.

  More specifically, the cleaning liquid is guided into the suction cap 16 by the pump 27 when the fixed matter adheres to the nozzle surface of the recording head 3 as described above due to the rebound of the ink. In this state, the cleaning liquid is filled and left for about 5 to 10 seconds, and then the suction cap is opened to suck the cleaning liquid in the cap. Thereafter, as described with reference to FIG. 3, wiping with a wiper blade can remove solid matter from the nozzle surface.

(Embodiment 3)
Similarly, there is an example described in Japanese Patent Application Laid-Open No. 2003-191480 as an example of performing cleaning with a cleaning liquid at the time of capping.

  FIG. 5 is a schematic cross-sectional view showing the ink discharge main body 11 of the recording head 3 and the cap main body in close contact with the ink discharge main body 11 according to the third embodiment.

  A supply port 43 for supplying the cleaning liquid from the cleaning liquid reservoir 41 into the suction cap 16 of the maintenance unit is open to the bottom surface 16 </ b> A of the suction cap 16. A supply path 42 is connected to the supply port 43 and is connected to the cleaning liquid tank 41 via a pump 52. The supply port 43 and the suction port 44 are in a relative positional relationship separated from each other in a direction substantially orthogonal to the direction of ink ejection from the nozzle opening. That is, in FIG. 5, the supply port 43 and the suction port 44 are in a relative positional relationship shifted in the left-right direction. Further, as shown by a two-dot chain line, a plurality of supply ports 43 can be arranged at another location.

  In each of the above embodiments, the distance between the surface of the nozzle surface and the bottom surface 16A of the suction cap 16 is set as narrow as possible.

  In the first embodiment, a supply path 42 extending from a cleaning liquid tank 41 storing a cleaning liquid is opened to a suction cap 16 and a suction chamber 45 formed by the nozzle surface through a supply port 43 provided on the nozzle surface side. It is what you are doing.

  Therefore, when the suction chamber 45 is in a negative pressure state during the cleaning operation, the high-viscosity ink stagnating in and near the nozzle opening and the cleaning liquid are sucked into the suction chamber 45. During this suction, the cleaning liquid vigorously flows into the suction chamber 45 by making the viscosity lower than that of the ink, and collides with the inner wall portion of the suction chamber 45, that is, the nozzle surface, the bottom surface 16A of the suction cap 16, and the like. Most of the cleaning liquid becomes small particles.

  On the other hand, because the viscosity is high, the high-viscosity ink sucked out later than the cleaning liquid interferes with the scattered cleaning liquid, and the two liquids are mixed, and the high-viscosity ink is diluted. It will be in the state. Further, when a negative pressure is applied to the suction chamber 45, the air in the suction chamber 45 flows during a transition period in which the pressure in the suction chamber 45 decreases. As a result, the suction chamber 45 exhibits agitation and turbulent flow by the cleaning liquid, high-viscosity ink, and flowing air.

  Due to the behavior of each fluid as described above, the scattered cleaning liquid itself or high-viscosity ink diluted with the cleaning liquid collides in a state of being splashed on the nozzle opening and its vicinity. The high-viscosity ink stagnating in the vicinity receives an aggressive cleaning action, and the clogging recovery is speeded up.

  Bubbles are generated during the agitation and turbulent phenomenon of each of the above fluids, but the ink that forms these bubbles is diluted with cleaning liquid, so even if the bubbles adhere near the nozzle opening, they immediately disappear. End up. Therefore, the abnormal ink ejection as described above due to the bubble adhesion is avoided.

  Further, since the viscosity of the ink as waste liquid collected in the suction cap 16 of the maintenance unit is reduced, the ink is sufficiently absorbed by the waste liquid absorbent in the waste liquid storage section 47, and the absorption capacity of the waste liquid storage section is as expected. Can be used.

  When the recording head 3 has not been used for a long time, the nozzle surface of the recording head is sealed with the suction cap 16. In this state, a cleaning liquid is supplied into the suction cap or cleaning is performed. By leaving the ink as waste liquid diluted with the liquid in the suction cap, the nozzle surface is placed in a water vapor atmosphere, so the viscosity of the ink stagnating in or near the nozzle opening is increased. It can be significantly reduced. Moreover, even if it does not do that, the same effect will be produced if the cleaning liquid evaporates from the supply port 43.

(Embodiment 4)
As a fourth embodiment, in a head-fixed ink jet recording apparatus using a large line type ink jet head, ink and cleaning liquid are respectively supplied to the recording head from a storage section, and cleaning is performed by switching the flow path. There is.

  FIG. 6 is a schematic configuration diagram of a recording head, an ink tank, and the like according to this embodiment.

  In this embodiment, in the recording head 3, the ink discharge main body 11 for discharging ink forms a piezoelectric ceramic plate in which ink grooves for forming each nozzle are formed, an ink chamber plate for sealing the same, and a nozzle surface. And a common ink chamber for supplying ink communicating with each nozzle to each nozzle. An open / close valve 103 for controlling the flow of ink is provided outside the ink discharge unit main body connected to the common ink chamber. Through this, an ink supply pipe 105 formed of a stainless steel pipe or the like is further connected to a sub tank 101 and an ink tank. 107.

  In this way, the ink from the ink tank 107 is temporarily held in the sub tank 101 and then supplied to the ink discharge main body of the recording head via the ink supply pipe 105. At this time, the on-off valve 104 for controlling the flow of the cleaning liquid described later is in a closed state. A supply pipe for supplying a cleaning liquid, which also communicates with the common ink chamber, is provided in parallel with the ink supply pipe outside the recording head ink discharge main body, and controls the flow of the cleaning liquid in the same manner as the ink supply pipe. An on-off valve 104 is provided through which a cleaning liquid supply pipe 106 formed of a stainless steel pipe or the like is connected, and a cleaning liquid tank 108 is connected to the other end side.

The cleaning liquid from the cleaning liquid tank 108 is sucked by the same suction cap (suction unit) 16 as in FIG. 5 to clean the inside of the recording head and the nozzles. The washed liquid is absorbed by the waste liquid storage section 47 through the waste liquid discharge pipe 46.
At this time, the on-off valve 104 for controlling the flow of the cleaning liquid is in an open state, and the on-off valve 103 for controlling the flow of ink is in a closed state.

  In this way, by providing a flow path dedicated to the cleaning liquid in parallel with the ink flow path, the fixed ink storage section having a large capacity and the ink flow path from the ink storage section to the ink jet head are long like a printing manufacturing facility. Even in an ink jet recording apparatus having a system configuration having a sub tank that temporarily holds ink in the middle of an ink supply pipe, printing can be performed in an appropriate maintenance state.

  In this embodiment, the ink flow path and the cleaning liquid flow path to the recording head ink discharge main body portion are arranged side by side. However, the present invention is not limited to this. For example, a three-way valve has the same function. It may be allowed. In any case, an ink jet recording apparatus excellent in maintainability can be provided by providing a cleaning liquid flow path different from the ink flow path in the vicinity of the flow path substrate so that the cleaning work can be performed and the recovery property after cleaning can be improved. Can be provided.

  As described above, several embodiments of the cleaning method using the cleaning liquid and the ink jet recording apparatus having the cleaning mechanism according to the present invention have been described, but the present invention is not limited thereto.

  The present invention is more specifically illustrated by the following examples.

<< Process for producing core-shell type colored fine particle dispersion >>
A core-shell type colored fine particle dispersion in which a polymer and a dye are compatible was prepared according to the following method.

<Synthesis Method of Core Polymer P>
A dropping device, a thermometer, a nitrogen gas introduction tube, a stirring device, and a reflux condenser were attached to a 3 liter four-necked flask, and 1000 g of ethyl acetate was heated to reflux. 500 g of styrene, 200 g of stearyl methacrylate and 300 g of acetoacetoxymethacrylate are weighed, and a mixed solution obtained by adding 20 g of N, N'-azobisisovaleronitrile to the monomer is added dropwise over 2 hours, and the reaction is carried out at the same temperature for 5 hours. After that, a core polymer P having a solid content of 50% by mass was obtained.

<Manufacturing process of core-shell type colored fine particle dispersion D>
18 g of FS Blue 1504 and 15 g of the above-mentioned core polymer P and ethyl acetate 140 g in terms of solid content were placed in a pot of CLEAMIX CLM-0.8S (M Technic Co., Ltd.), and the dye was completely dissolved by stirring. . 9 g of Aqualon KH-05 (Daiichi Kogyo Seiyaku Co., Ltd.) was added to 258 g of pure water, added to the dye solution, and emulsified for 5 minutes at a rotational speed of 20000 rpm. Thereafter, ethyl acetate was removed under reduced pressure to obtain a colored fine particle dispersion.

260 g of the colored fine particle dispersion was transferred to a three-separable flask, the inside of the flask was replaced with N ₂ , and then heated to 80 ° C. with a heater. A mixed liquid of 4 g of methyl methacrylate and 0.5 g of N, N′-azobisisovaleronitrile was added dropwise over 1 hour, and further reacted for 6 hours to obtain a core-shell type colored fine particle dispersion D.

<Ink I creation>
63 g of core-shell colored fine particle dispersion D prepared by the above method, 15 g of ethylene glycol, 15 g of glycerin, 0.5 g of Orphine E1010 (manufactured by Nissin Chemical), and preservative Proxel GXL (manufactured by Avecia) 0.1 g was mixed and pure water was added to make 100 g. Subsequently, it was filtered through a 0.8 μm membrane filter to remove dust and coarse particles, thereby preparing an inkjet ink I.

《Creating cleaning liquid》
5 g of diethanolamine and 0.1 g of a preservative Proxel GXL (Avecia) were mixed, and pure water was added to make 100 g. Next, this was filtered through a 0.8 μm membrane filter to remove dust and coarse particles to prepare a cleaning liquid CL-1. Subsequently, CL-2 to CL-8 and CL-A to CL-F were similarly prepared according to the formulation in Table 1.

(Evaluation 1)
<Evaluation of cleaning liquid>
10 g of ink I and 10 g of cleaning liquids CL- 1 to 3, CL-A, and CL-B were weighed and mixed, and after stirring well, diluted 1000 times, the scattering intensity of Zetasizer 1000 (Malvern) The measurement was carried out five times by distribution measurement, and the average value was measured by arithmetically averaging the measured values. The average particle size of each liquid mixture was divided by the average particle size of ink I measured separately to determine how many times the particle size increase occurred with respect to the ink. The average particle size of ink I was 30 nm.

<Cleanability evaluation>
As the evaluation apparatus, the inkjet apparatus shown in FIG. 1 was used, and a maintenance unit including a sprayer for cleaning the recording head by spraying the cleaning liquid shown in the first embodiment, that is, FIG. A thing was used. The ink cartridge was filled with the ink, the cleaning liquid was filled in the cleaning liquid tank 23, and the cleaning property was evaluated under the following conditions.

  The evaluation apparatus was installed in an environment of 15 ° C. and 40% RH, and after ink I was continuously discharged for 5 minutes, the nozzle surface was left without being capped for 10 minutes. The cleaning liquid was sprayed on the nozzle surface of the head, and cleaning was performed by wiping the nozzles with a wiper blade, and the number of cleaning processes was evaluated to completely recover nozzle clogging.

◎ Recover in 1 time ○ Recover in 2 to 3 times △ Recover in 4 to 5 times × No recovery even after cleaning 5 times Results shown in the above criteria are shown.

  It can be seen that those having a particle size increase in the range of the present invention have good cleaning properties.

(Evaluation 2)
<Evaluation of cleaning liquid>
10 g of ink I, 10 g of cleaning liquids CL-4 to 6, CL-C and CL-D were weighed and mixed. After stirring well, sealed in a 20 ml scree tube bottle and allowed to stand at 60 ° C. for 7 days. I put it. After measuring 2 g of the supernatant and diluting it 1000 times with pure water, spectral absorption from 350 nm to 800 nm was measured using a spectrophotometer UVIDFC-610 (manufactured by Shimadzu Corporation). Absorbance was calculated by multiplying the measured value at the maximum absorption wavelength by the dilution factor. The absorbance of each mixed solution was divided by the separately measured absorbance of ink I to determine what percentage of the mixed solution was absorbed with respect to the ink. The absorbance of Ink I measured separately was 1025.

<Cleanability evaluation>
As the evaluation apparatus, as shown in the fourth embodiment, that is, as shown in FIG. 6, in addition to the ink supply pipe 105 from the ink tank 107, the cleaning liquid supply pipe 106 is provided in parallel with the ink discharge section main body of the recording head. An ink jet apparatus using a recording head capable of supplying a cleaning liquid to each nozzle from the discharge unit main body was used.

  As shown in FIG. 6, the ink was filled in the ink tank 107 and the cleaning liquid was filled in the cleaning liquid tank 108, and the cleaning properties were evaluated under the following conditions.

  The evaluation apparatus was installed in an environment of 15 ° C. and 40% RH, and after ink I was continuously discharged for 5 minutes, the nozzle surface was left without being capped for 10 minutes. Next, the recording head was moved to the maintenance unit, a suction cap was attached to the nozzle surface, the on-off valve 103 of the ink supply path 105 was closed, and the on-off valve 104 for controlling the flow of the cleaning liquid was opened. The cleaning liquid was sucked with a negative pressure from a suction cap opposed to the nozzle surface, and then wiped with a wiper blade. It was evaluated how many times the above cleaning operation was performed to completely recover from nozzle clogging.

◎ Recovery in one time ○ Recovery in 2 to 3 times △ Recovery in 4 to 5 times × No recovery even after cleaning 5 times The results of evaluation based on the above evaluation criteria are shown below.

  As described above, those using a cleaning liquid that was 35% or less of the absorbance of the original ink after mixing and leaving with ink had good cleaning properties.

(Evaluation 3)
<Evaluation of cleaning liquid>
The following values A and B were measured using a spectrophotometer UVIDFC-610 (manufactured by Shimadzu Corporation), and the cleaning liquids CL-7, CL-8, CL-E, and CL-F | B-A / A | Asked.
A: Absorbance calculated by diluting ink I 1000 times with pure water, measuring spectral absorption in the range of 350 nm to 800 nm, and multiplying the measured value at the maximum absorption wavelength by the dilution rate.
B: Absorbance calculated by diluting ink I 1000 times with a cleaning liquid, measuring spectral absorption in the range of 350 nm to 800 nm, and multiplying the measured value at the maximum absorption wavelength by the dilution rate.

  The measured absorbance (A) of ink I was 1025.

<Cleanability evaluation>
The ink jet recording apparatus described in FIG. 5 (the third embodiment) was provided with an inlet for introducing a cleaning liquid at the bottom of the cap body of the maintenance unit. In the apparatus, the cleaning liquid reservoir 41 was filled with the cleaning liquid, and the ink cartridge was filled with ink I, and the cleaning performance was evaluated as follows.

  The ink jet recording apparatus was installed in an environment of 15 ° C. and 40% RH, and after ink I was continuously discharged for 5 minutes, it was left for 10 minutes without capping the nozzle surface. Next, the recording head was moved to the maintenance unit, a suction cap was attached to the nozzle surface, and the cleaning liquid and ink were simultaneously sucked by the negative pressure in the suction chamber 45 formed from the cap and the nozzle surface according to the third embodiment. After suction of the cleaning liquid, wiping with a wiper blade was performed. Thereafter, the ink was discharged again, and the state of nozzle clogging was evaluated.

◎ All nozzles recovered and emitted normally ○ All nozzles clogged, but slanted emission was seen with 1-2 nozzles △ All nozzles clogged, but 3-5 Diagonal emission was observed at the nozzle. X Nozzle clogging was not recovered, and nozzles with missing emission were observed. The results of evaluation based on the above evaluation criteria are shown below.

  Again, those using the cleaning liquid according to the present invention had good cleaning properties.

It is the schematic which shows an example of the main structures of an inkjet recording device. FIG. 2 is a schematic diagram illustrating a configuration of a recording head. It is a figure which shows typically the structure for the discharge recovery which concerns on 1st Embodiment. It is a figure which shows typically the structure for the fixed matter removal which concerns on 2nd Embodiment. FIG. 10 is a schematic cross-sectional view illustrating a recording head according to a third embodiment and a state in which a cap body is in close contact with the recording head. It is a schematic block diagram of the recording head, ink tank, etc. which concern on 4th Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inkjet recording device 2 Recording paper 3 Recording head 4 Carriage 5 Maintenance unit 6 Guide rail 8 Moisturizing cap C Ink cartridge T Sub tank 9 Print area 10 Head substrate 11 Ink ejection main body part 12 Temperature sensor 13 Flexible cable connection part 14 Ejection port 16 Suction Cap 17, 31, 32 Wiper blade 21 Sprayer 23, 41 Cleaning liquid tank 25 Supply pipe 27, 37, 52 Pump 36, 46 Discharge pipe 39 Waste liquid reservoir 42 Supply path 43 Supply port 44 Suction port 47 Waste liquid storage unit 101 Sub tank 103, 104 On-off valve 105 Ink supply pipe 106 Cleaning liquid supply pipe 107 Ink tank 108 Cleaning liquid tank

Claims (6)

In an ink jet recording apparatus using an ink in which colored fine particles composed of a color material and a polymer are dispersed and having a cleaning mechanism for cleaning a recording head with a cleaning liquid, the mass ratio of the ink and the cleaning liquid is 1: 1. The recording head is cleaned using a cleaning liquid in which the volume average particle diameter of the mixed liquid (25 ° C.) when mixed in step 1 is 1.2 times or more the average particle diameter of the ink alone. An ink jet recording apparatus. A cleaning liquid in which the volume average particle diameter of the mixed liquid (25 ° C.) when the ink and the cleaning liquid are mixed at a mass ratio of 1: 1 is 1.4 times or more than the average particle diameter of the ink alone. The ink jet recording apparatus according to claim 1, wherein the ink jet recording apparatus is used. In an ink jet recording apparatus having a cleaning mechanism for cleaning a recording head using a cleaning liquid using ink in which colored fine particles composed of a color material and a polymer are dispersed, the ink and the cleaning liquid are mixed at a mass ratio of 1: 1. Mix and leave for 7 days in an environment of 60 ° C. After mixing the ink and the cleaning liquid, the absorbance after mixing the ink and the cleaning liquid measured by the absorbance measurement method shown below is compared with the ink absorbance. An ink jet recording apparatus, wherein the head is cleaned using a cleaning liquid having an absorbance of 35% or less compared to the absorbance of the ink before mixing.
Absorbance measurement method: The ink and the cleaning liquid were mixed at a mass ratio of 1: 1, and the supernatant of 10% by mass of the upper part of the liquid that was allowed to stand in an environment of 60 ° C. for 7 days was measured and diluted with pure water to 350- Spectral absorption is measured in the range of 800 nm (25 ° C.), and the absorbance at the maximum absorption wavelength is multiplied by the dilution factor. The inkjet according to claim 3, wherein a cleaning liquid is used such that when the absorbance before and after mixing is measured by the absorbance measurement method, the absorbance after mixing is 25% or less compared to before mixing. Recording device. In an ink jet recording apparatus having a cleaning mechanism for cleaning a recording head using a cleaning liquid, using ink in which colored fine particles composed of an oil-soluble dye and a polymer are dispersed, the values of A and B defined below are as follows: An inkjet recording apparatus using a cleaning liquid that satisfies a relationship represented by the following formula.

A: Absorbance calculated by diluting the ink used in the recording apparatus with pure water, measuring the spectral absorption in the range of 350 nm to 800 nm (25 ° C.), and multiplying the measured value at the maximum absorption wavelength by the dilution rate.
B: Absorbance calculated by diluting the ink used in the recording apparatus with a cleaning liquid, measuring spectral absorption in the range of 350 nm to 800 nm (25 ° C.), and multiplying the measured value at the maximum absorption wavelength by the dilution rate. Measures the absorbance of ink in the range of 350 nm to 800 nm in an ink jet recording apparatus equipped with a cleaning mechanism for cleaning a recording head using a cleaning liquid, using ink in which colored fine particles composed of an oil-soluble dye and a polymer are dispersed. An ink jet recording apparatus comprising: a cleaning liquid having a different number of spectral peaks depending on whether the measurement dilution solvent is pure water or the cleaning liquid.

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