JP2005319698A - Inkjet recorder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet recorder capable of detecting a defective nozzle by maintaining a predetermined printing speed. <P>SOLUTION: This serial type inkjet recorder moves in a main scanning direction a recording head having nozzles arranged in a sub-scanning direction by each color of ink and drives a paper in the sub-scanning direction to record an image such that the recording head ejects inks of at least two colors on the paper. In the body 111 of the recorder, the length of a nozzle array of each color of ink is made to be in the range from 38 to 100 mm. The recorder is equipped with a maintenance device 147 that comprises an idling ejection receiver having an absorber for absorbing liquid droplets of ink ejected for idling when the nozzle array ejects the ink by each color in the non-recording time, and a light emitting section and a light receiving section which are attached to the idling ejection receiver and detects the ejection condition of the ink during the idling ejection. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an ink jet recording apparatus having a recording head for discharging ink liquid.

  The printing speed of the ink jet recording apparatus is determined by the formation time per pixel and the number of nozzles. Among these, the formation time per pixel is a basic characteristic of the recording head itself, and a significant improvement cannot be expected in a short period. For this reason, the printing speed of the ink jet recording apparatus has been improved by increasing the number of nozzles per ink color and increasing the length. For example, in a serial type ink jet recording apparatus, when the scan width of one scan is increased, the number of scans can be reduced, so that the printing speed can be improved. However, in an ink jet recording apparatus, there is a frequency with a so-called “nozzle missing” in which the ejection state from unspecified nozzles becomes defective, and in particular, nozzle missing occurs due to the lengthening of the recording head and the increase in nozzle density. Becomes prominent. Therefore, in order to improve the printing speed and stabilize the printing quality, it is necessary to reliably detect missing nozzles.

  Therefore, the conventional ink jet recording apparatus includes a pair of electrode plates in the vicinity of the nozzles in the ink discharge direction of the recording head, and a resonance circuit is configured by connecting a coil and an oscillator in series to the electrode plate pair. The oscillation frequency is adjusted so as to be in a resonance state when no ink droplet is present in the ink (see, for example, Patent Document 1). With this configuration, it is possible to detect that ink droplets have passed between both electrode plates based on the deviation of the resonance state, and further detect the size of the ink droplets, and cope with abnormalities such as missing nozzles before printing. It is expected.

  In addition, an ink droplet detection unit having a light emitting unit that emits light and a light receiving unit that receives light from the light emitting unit in the vicinity of the recording head, a feed mechanism that relatively moves the recording head and the ink droplet detection unit, When the recording head and the ink droplet detector are relatively moving at a constant speed, the ink droplet is detected, the time interval between successive ink droplet detection pulses is compared with a predetermined threshold value, and the result is Some of them are counted to determine whether or not there is a non-operating nozzle (see, for example, Patent Document 2).

  In addition, the apparatus includes: a means for optically detecting ink droplets ejected by the nozzles of the recording head, obtaining ejection characteristic data; a means for adjusting the nozzle drive waveform; and a means for cleaning the recording head. If it is not detected, the recording head may be cleaned (for example, see Patent Document 3).

  A flow path forming member including a plurality of flow path patterns independently including a plurality of pressurized liquid chambers communicating with the nozzles of the recording head, and a flow path formed by the plurality of flow path patterns; In some cases, ink inlets formed independently are interposed between the common liquid chambers that supply ink to a plurality of pressurized liquid chambers (see, for example, Patent Document 4). With this configuration, it is expected that the nozzle omission accompanying the increase in the length of the recording head and the increase in the density of the nozzles is reduced, and the mechanical strength of the flow path forming member is improved.

As an approach to improving the image quality of plain paper, it is generally known that a pigment is used as an ink colorant and a resin dispersant is used as the dispersant.
Japanese Unexamined Patent Publication No. 2000-158670 (page 5, FIG. 1 etc.) JP-A-2002-192740 (pages 7 to 9, FIG. 3, FIG. 8, etc.) JP 2003-127430 A (pages 4 to 5, FIG. 2, FIG. 9, etc.) JP 2004-106364 A (pages 5-7, FIG. 1, FIG. 4 etc.)

  However, the conventional ink jet recording apparatuses described in Patent Document 1 to Patent Document 3 have a problem in that since the procedure for detecting missing nozzles is added, the control is complicated and the printing speed may decrease. . Furthermore, in the conventional ink jet recording apparatus described in Patent Document 4, no consideration has been given to detecting missing nozzles while maintaining a predetermined printing speed.

  SUMMARY An advantage of some aspects of the invention is that it provides an ink jet recording apparatus capable of detecting missing nozzles while maintaining a predetermined printing speed.

  In order to solve the above problem, an ink jet recording apparatus according to a first aspect of the present invention provides a predetermined recording medium while driving a recording head having nozzles aligned in the sub-scanning direction for each ink color in the main scanning direction. Is a serial type ink jet recording apparatus in which an image is recorded by ejecting at least two or more colors of ink onto a predetermined recording medium, in which nozzles are arranged for each ink color. The ink discharge means has a discharge ink absorbing means having an absorber that receives and absorbs the droplets of the ink that is discharged when the nozzle row discharges the ink for each ink color during non-recording. The idle discharge holding unit includes a discharge state detecting unit that detects an ink discharge state during the idle discharge.

  An ink jet recording apparatus according to a second aspect of the present invention is the ink jet recording apparatus according to the first aspect, wherein at least one color of ink contains a pigment coated with a resin dispersant as a colorant, and the particle diameter of the pigment is The configuration is set to 0.01 μm to 0.03 μm.

  Furthermore, the ink jet recording apparatus of the present invention according to claim 3 is the structure according to claim 2, wherein the amount of the resin dispersant in the ink of at least one color is 0.5% by mass to 10% by mass. Have.

  In the present invention, when the length of the nozzle row for each ink color is 38 mm to 100 mm, and the nozzle row ejects ink for each ink color during non-printing, it receives and absorbs the ink droplets ejected idle. An empty discharge ink absorbing means having an absorber is provided, and the empty discharge holding means is provided with a discharge state detection means for detecting an ink discharge state at the time of empty discharge, so that a sequence for nozzle detection is not added, Since it is possible to detect the ejection state of the nozzles when idle ejection is performed, it is possible to provide an ink jet recording apparatus that has the effect of being able to detect missing nozzles while maintaining a predetermined printing speed.

  Hereinafter, an ink jet recording apparatus according to an embodiment of the present invention will be described with reference to the drawings.

  An ink jet recording apparatus according to an embodiment of the present invention is shown in FIGS. FIG. 1 shows the main body of the ink jet recording apparatus, and FIG. 2 shows the entire apparatus including the main body.

  1 and 2, the ink jet recording apparatus 1 houses a carriage 123 that can move in the main scanning direction inside a main body 111 and a printing mechanism unit 112 including a recording head 124 mounted on the carriage 123. A paper feeding cassette 114 capable of stacking a large number of sheets 113 from the front side (left side in FIG. 2) can be detachably attached to the lower part of the main body 111, and the sheets 113 can be manually fed. The manual feed tray 115 can be turned down, the paper 113 fed from the paper feed cassette 114 or the manual feed tray 115 is taken in, a required image is recorded by the printing mechanism 112, and then the rear side (FIG. 2). The paper is discharged to a paper discharge tray 116 mounted on the right side. Note that a paper feed tray may be used instead of the paper feed cassette 114.

  The printing mechanism 112 includes a main guide rod 121 and a secondary guide rod 122 that are horizontally mounted on left and right side plates (not shown), and moves the carriage 123 in the main scanning direction (direction perpendicular to the conveyance direction of the paper 113 ( Slidably held in the width direction). The carriage 123 includes a plurality of recording heads 124 that eject ink droplets of each color of yellow (Y), cyan (C), magenta (M), and black (Bk) (hereinafter also referred to as “ink droplets”). Are arranged in a direction crossing the main scanning direction (corresponding to the sub-scanning direction), and the ink droplet discharging direction is directed downward. In the ink described above, a pigment is used as a color material, and in the Y, M, and C inks, a resin dispersant is used for the purpose of maintaining the dispersion state of the pigment. The carriage 123 is also provided with a negative pressure generating mechanism 125 that supplies ink of each color to the recording head 124 and keeps the inside of the recording head 124 at a negative pressure. Ink is supplied from the Y, C, M, and Bk ink tanks to the negative pressure generating mechanism 125 via an ink supply mechanism (not shown).

  Further, although the recording heads 124 are provided for the respective colors Y, C, M, and Bk, a single recording head having nozzles that eject ink droplets of the respective colors may be used. Here, the carriage 123 is slidably fitted to the main guide rod 121 on the rear side (downstream side in the paper conveyance direction), and slidable on the front guide rod 122 on the front side (upstream side in the paper conveyance direction). It is mounted on. In order to move and scan the carriage 123 in the main scanning direction, a timing belt 130 is stretched between a driving pulley 128 that is rotationally driven by a main scanning motor 127 and a driven pulley 129 that rotates with the driving pulley 128. The timing belt 130 is fixed to the carriage 123. Here, the carriage 123 is driven to reciprocate by forward and reverse rotation of the main scanning motor 127.

  On the other hand, in order to convey the sheet 113 set in the sheet feeding cassette 114 to below the recording head 124, the sheet 113 is guided from the sheet feeding cassette 114 and the friction pad 132, and the sheet 113 is guided. A guide member 133, a transport roller 134 that reverses and transports the fed paper 113, a driven roller 135 that is pressed against the peripheral surface of the transport roller 134, and a leading end that defines the feed angle of the paper 113 from the transport roller 134 A roller 136. The transport roller 134 is rotationally driven by a sub-scanning motor 137 via a gear train.

  The printing receiving member 139 is a sheet guide member that guides the sheet 113 fed from the conveyance roller 134 to the lower side of the recording head 124 corresponding to the movement range of the carriage 123 in the main scanning direction. It is arranged below. On the downstream side of the printing receiving member 139 in the paper transport direction, a transport roller 141 and a spur 142 that are rotationally driven to feed the paper 113 in the paper discharge direction are provided, and paper discharge that further feeds the paper 113 to the paper discharge tray 116. A roller 143 and a spur 144, and guide members 145 and 146 that form a paper discharge path are disposed. Here, at the time of recording, the recording head 124 is driven in accordance with the image signal while moving the carriage 123, thereby ejecting ink onto the stopped sheet 113 to record one line, and the sheet 113 is recorded in a predetermined amount. The next line is recorded after conveyance. Upon receiving a recording end signal or a signal indicating that the trailing edge of the sheet 113 has reached the recording area, the recording operation is terminated and the sheet 113 is discharged.

  With the configuration described above, the controllability of ink droplet ejection of the recording head 124 is improved, characteristic fluctuations are suppressed, and high-quality images can be recorded stably.

  A maintenance device 147 for maintaining and recovering the ejection state of the recording head 124 is disposed at a position outside the recording area on the right end side in the movement direction of the carriage 123. The maintenance device 147 includes a cap unit for capping the recording head 124, a suction unit for sucking out bubbles and the like from the ejection port of the recording head 124, and a cleaning unit for removing and cleaning ink and dust adhering to the ejection port surface. Is functioning as Here, when the carriage 123 moves to the maintaining device 147 side during printing standby, the ejection head portion of the recording head 124 is kept in a wet state by capping the recording head 124 to prevent ejection failure due to ink drying. I am doing so. In addition, during the recording or the like, the recording head 124 discharges ink that is not related to the recording, so that the ink viscosity of all the discharge ports is made constant and the stable discharge performance is maintained. Furthermore, when a discharge failure occurs, the maintenance device 147 seals the discharge port of the recording head 124 as a cap unit, and sucks out bubbles and the like from the discharge port through a tube (not shown) as a suction unit. As a cleaning means, ink, dust, or the like adhering to the discharge port surface is removed by means of removal so that the discharge failure is eliminated. Further, the ink sucked by the maintaining device 147 as the suction means is discharged to a waste ink reservoir (not shown) installed at the lower part of the main body and absorbed and held by an ink absorber inside the waste ink reservoir.

  Next, a perspective view of the recording head 124 is shown in FIG.

  In FIG. 3, a negative pressure generating mechanism 125 is connected to the recording head 124, and ink is supplied to the recording head 124 via the negative pressure generating mechanism 125. This ink is ejected from the nozzle 31. The nozzles 31 are formed in two rows per head, and there are 320 nozzles with a pitch of 169.3 μm per row, and the rows are aligned with a half pitch shift. Therefore, the total number of nozzles 31 is 640 with a pitch of 84.65 μm, and the length of the nozzle row is about 54 mm.

  Next, an outline of the maintenance device 147 is shown in FIG.

  In FIG. 4, in the cap mechanism 43 (corresponding to the cap means), four caps 40 are arranged corresponding to the respective recording heads. Next to the cap mechanism 43, a wiper mechanism 44 (corresponding to a cleaning means) is arranged, and the wiper 41 wipes the nozzle surface. Next to the wiper mechanism 44, an idle discharge receiver 42 is disposed. The cap mechanism 43 includes a suction mechanism (corresponding to a suction unit) that sucks out bubbles and the like from the ejection port of the recording head 124 through a tube.

  Next, the configuration of the idle discharge receiver 42 is shown in FIG.

  In FIG. 5, an absorber (not shown) that absorbs and holds ink is laid on the bottom of the idle discharge receiver 42. In addition, a light emitting unit 51 and a light receiving unit 52 are disposed above the idle ejection receiver 42 so that the ejection state of ink from each nozzle can be optically monitored during idle ejection.

  Next, a component configuration of the recording head 124 is shown in FIG.

  With this configuration, the ink is supplied from the ink supply port 69 provided in the frame 64, distributed by the common liquid chamber in the frame 64, and passed through the vibration plate 65 to the individual liquid chamber provided in the flow path plate 66. And the ink is discharged from the nozzle 31 provided on the nozzle plate 67. These are arranged almost line-symmetrically with respect to the nozzle array direction, and form one recording head 124. The piezoelectric element 63 is formed by joining two elements to one base 61. After being grooved so as to correspond to the individual liquid chamber described above, an FPC cable 62 is joined to form an actuator unit. It is what you do. The central portion of the frame 64 is opened in a cylindrical shape, and the actuator unit is accommodated in the opening. Here, as described above, since a long head having a nozzle row length of about 54 mm (> 38 mm) is used, it is important to ensure the rigidity of the base 61 and the frame 64. On the other hand, in the serial printer of this embodiment, the carriage 123 including the recording head 124 is reciprocated at a high speed, so that the load on the main scanning mechanism increases according to the weight of the recording head 124, and further, Noise increases. Specifically, an increase in the weight of the recording head 124 makes it difficult to suppress an increase in vibration associated with driving the head, and this vibration causes a decrease in ejection stability. Therefore, in order to ensure the rigidity of the base 61 and the frame 64, it is not preferable to adopt a configuration that easily increases the weight of the recording head 124. In addition, when the nozzle row length exceeds 100 mm, the increase in the printing speed corresponding to the increase in the nozzle row length is negligible and the industrial meaning is lost.

  Next, the recording liquid used in this embodiment will be described in detail. Here, as described above, the resin-dispersed pigment ink is used for the color ink. The resin dispersant contained in the pigment ink may remain stochastically during wiping, which is one cause of nozzle down. This nozzle down makes it difficult to secure the jetting stability and stabilize the image quality. Therefore, in the present embodiment, the recording liquid described below is used. The recording liquid used in the present embodiment uses a pigment as a color material, but it can also be used by mixing a dye.

  Although there is no limitation in particular as a pigment used for the recording liquid of this embodiment, For example, the pigments listed below are used suitably. Moreover, you may use these pigments in mixture of multiple types.

  Organic pigments include azo, phthalocyanine, anthraquinone, quinacridone, dioxazine, indigo, thioindigo, perylene, isoindolenone, aniline black, azomethine, rhodamine B lake pigment, carbon black, etc. Can be mentioned.

  Examples of inorganic pigments include iron oxide, titanium oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, bitumen, cadmium red, chrome yellow, and metal powder.

  The particle diameter of the pigment described above is preferably 0.01 to 0.30 [mu] m, and if it is 0.01 [mu] m or less, the particle diameter approaches that of the dye, so that light resistance and feathering deteriorate. On the other hand, if it is 0.30 μm or more, clogging of the recording head or clogging with a filter in the printer occurs, and it is not possible to obtain ejection stability.

  The carbon black used in the black pigment ink is carbon black produced by the furnace method or the channel method, the primary particle size is 15 to 40 millimicrons, and the specific surface area by the BET method is 50 to 300 square meters / g, DBP oil absorption is preferably 40 to 150 ml / 100 g, volatile content is 0.5 to 10%, and pH value is 2 to 9. More specifically, for example: 2300, no. 900, MCF88, No. 40, no. 52, MA7, MA8, no. 2200B (above, manufactured by Mitsubishi Kasei), RAVEN 1255 (made in Colombia), REGAL400R, REGAL660R, MOGUL L (above, manufactured by Kibobot), Color Black FW1, Color Black FW18, Color Black S170, Color Black S150, Printex35, Printex U (above , Manufactured by Degussa) or the like can be used.

  Furthermore, specific examples of the color pigment are listed below.

  As described above, azo, phthalocyanine, anthraquinone, quinacridone, dioxazine, indigo, thioindigo, perylene, isoindolenone, aniline black, azomethine, rhodamine B lake pigment, carbon as organic pigments Examples of the inorganic pigment include iron oxide, titanium oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, bitumen, cadmium red, chrome yellow, and metal powder.

  Here, the particle size of the pigment can be measured using a particle size distribution meter. Specifically, the recording liquid can be diluted 200 to 1000 times with ion-exchanged water and measured with a particle size distribution meter (Nikkiso Co., Ltd., Microtrac UPA150). The 50% average particle diameter (D50) is defined as the average particle diameter of the pigment.

  The pigment according to this embodiment is coated with a resin dispersant. By coating the pigment particles with a resin dispersant, it is possible to improve the high color developability and the scratch of printed matter. As a resin dispersant for stably dispersing a water-insoluble colorant in water, a dispersion having a hydrophobic part having affinity for the water-insoluble colorant and a hydrophilic part having affinity for water There is no particular limitation as long as it is a water-soluble resin known as an agent. Examples of such resin dispersants include, for example, styrene, styrene derivatives, vinyl naphthalene, vinyl naphthalene derivatives, aliphatic alcohol esters of α, β-ethylenically unsaturated carboxylic acids, acrylic acid, acrylic acid derivatives, maleic acid, At least two or more monomers selected from maleic acid derivatives, itaconic acid, itaconic acid derivatives, fumaric acid, fumaric acid derivatives, vinyl acetate, vinyl pyrrolidone, acrylamide, and derivatives thereof (of which at least one is And a block copolymer, a random copolymer, a graft copolymer, or a salt thereof. Among these, a particularly preferable dispersant is a block copolymer.

  By the way, the resin dispersant used in the ink for thermal ink jet recording has an influence on the ejection of the ink even if at least an amount necessary for the dispersion of the water-insoluble colorant, preferably an amount larger than that, is present in the ink. It is needless to say that it is preferable to use one that does not give or has little influence from the viewpoint of ejection stabilization during high frequency driving. Among the resin dispersants, those having a block structure, that is, a block copolymer are very preferable for meeting this purpose.

  This block copolymer has a structure represented by, for example, AB, BAB and ABC types. Here, A, B and C each represent a polymer block having a different structure. A block copolymer having a hydrophobic block and a hydrophilic block and having a balanced block size that contributes to dispersion stability is particularly advantageous in this embodiment. Specifically, a functional group can be incorporated into a hydrophobic block (a block to which a water-insoluble colorant binds), thereby improving the dispersion stability, so that the uniqueness between the dispersant and the water-insoluble colorant can be improved. Interaction is further enhanced. Further, an inkjet head that is used in an inkjet recording system that uses thermal energy, particularly for small droplets (for example, an ink ejection amount per ejection operation is 20 pl (picoliter) or less, more specifically 0.1 to 20 pl, In particular, when used in an ink jet head of 0.1 to 15 pl, more preferably 0.1 to 10 pl, a more preferable action is obtained due to its rheological suitability. Here, the ink discharge amount per discharge operation is specifically the ink amount per dot, for example.

  The amount of the polymer (dispersant) in the ink depends on the structure, molecular weight, and other characteristics of the polymer, as well as other components of the ink composition. The weight average molecular weight of the polymer selected in this embodiment is less than 30,000, preferably less than 20,000, particularly preferably in the range of 2,000 to 10,000.

  Regarding the method for producing the above-mentioned polymer, JP-A Nos. 05-179183, 06-136411, 07-053841, 10-87768, 11-043639, It is disclosed in JP-A-11-236502 and JP-A-11-269418.

  In addition, examples of the hydrophobic monomer that can be used in the block copolymer described above include, but are not limited to, the following monomers. For example, benzyl acrylate, benzyl methacrylate, methyl methacrylate (MMA), ethyl methacrylate (EMA), propyl methacrylate, n-butyl methacrylate (BMA or NBMA), hexyl methacrylate, 2-ethylhexyl methacrylate (EHMA), octyl methacrylate, lauryl methacrylate ( LMA), stearyl methacrylate, phenyl methacrylate, hydroxyethyl methacrylate (HEMA), hydroxypropyl methacrylate, 2-ethoxyethyl methacrylate, methacrylonitrile, 2-trimethylsiloxyethyl methacrylate, glycidyl methacrylate (GMA), p-tolyl methacrylate, sorbyl Methacrylate, methyl acrylate, ethyl acrylate Propyl acrylate, butyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, octyl acrylate, lauryl acrylate, stearyl acrylate, phenyl acrylate, 2-phenylethyl methacrylate, hydroxyethyl acrylate, hydroxypropyl acrylate, acrylonitrile, 2-trimethylsiloxyethyl acrylate Glycidyl acrylate, p-tolyl acrylate, sorbyl acrylate. Among them, preferred hydrophobic monomers are benzyl acrylate, benzyl methacrylate, 2-phenylethyl methacrylate, methyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, and homopolymers or copolymers thereof such as copolymers of methyl methacrylate and butyl methacrylate. It is preferable to produce a block copolymer.

  Further, examples of the hydrophilic monomer that can be used in the block copolymer include the following monomers, but are not limited thereto. For example, methacrylic acid (MAA), acrylic acid, dimethylaminoethyl methacrylate (DMAEMA), diethylaminoethyl methacrylate, tert-butylaminoethyl methacrylate, dimethylaminoethyl acrylate, diethylaminoethyl acrylate, dimethylaminopropyl methacrylamide, methacrylamide, acrylamide Dimethylacrylamide. Among them, it is preferable to produce a block copolymer using a homopolymer or copolymer of methacrylic acid, acrylic acid or dimethylaminoethyl methacrylate.

  Also, the acid-containing polymer is made directly or from a blocked monomer having a blocking group that is removed after polymerization. Blocked monomers that yield acrylic acid or methacrylic acid after removal of the blocking group include trimethylsilyl methacrylate (TMS-MAA), trimethylsilyl acrylate, 1-butoxyethyl methacrylate, 1-ethoxyethyl methacrylate, 1-butoxyethyl acrylate, 1 -Ethoxyethyl acrylate, 2-tetrahydropyranyl acrylate, 2-tetrahydropyranyl methacrylate and the like.

  When the above-described block copolymer is used as a recording liquid, and particularly when a recording head using thermal energy is driven at a high frequency (for example, 5 KHz or more, particularly 10 kHz or more), the effect of improving the ejection property is more remarkable. Become.

  The amount of the resin dispersant in the ink is preferably 0.5% by mass or more, more preferably 0.8% by mass or more, particularly preferably 1% by mass or more, and preferably 10% by mass or less. More preferably, it is 8 mass% or less, Especially preferably, it is the range of 6 mass% or less. Within this range, it is easy to maintain the ink viscosity within a practical range as an inkjet ink.

  Further, in order to make the recording liquid according to the present embodiment have desired physical properties or to prevent clogging of the nozzles of the recording head due to drying, it is preferable to use a water-soluble organic solvent in addition to the above-described color material. . This water-soluble organic solvent includes a wetting agent and a penetrating agent.

  The wetting agent is added to prevent clogging of the nozzles of the recording head due to drying. Specific examples of the wetting agent include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, propylene glycol, 1,3-butanediol, 1,3-propanediol, and 2-methyl-1,3-propane. Diol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, glycerin, 1,2,6-hexanetriol, 2-ethyl-1,3-hexanediol, 1,2 Polyhydric alcohols such as 1,4-butanetriol, 1,2,3-butanetriol, and petriol, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene Polyhydric alcohol alkyl ethers such as glycol monobutyl ether, triethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether and propylene glycol monoethyl ether, polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether Forehead: Nitrogen-containing heterocyclic compounds such as N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone, 2-pyrrolidone, 1,3-dimethylimidazolidinone, ε-caprolactam; formamide, N-methylformamide, Amides such as formamide and N, N-dimethylformamide; monoethanolamine, diethanolamine, triethanolamine, monoethylamine, diethylamine, triethyl Examples thereof include amines such as ruamine, sulfur-containing compounds such as dimethyl sulfoxide, sulfolane and thiodiethanol, propylene carbonate, ethylene carbonate, and γ-butyrolactone. These water-soluble organic solvents are used alone or in combination with water.

  Further, the penetrant is added to improve the wettability between the recording liquid and the recording material and adjust the penetration speed. As the penetrant, those represented by the following formulas 1) to 4) are preferable.

  Here, a polyoxyethylene alkylphenyl ether surfactant of formula 1), an acetylene glycol surfactant of formula 2), a polyoxyethylene alkyl ether surfactant of formula 3) and a polyoxyethylene of formula 4) Since the polyoxypropylene alkyl ether surfactant reduces the surface tension of the liquid, the wettability of the recording liquid can be improved and the penetration rate can be increased.

  Further, other than the compounds represented by the above formulas 1) to 4), for example, diethylene glycol monophenyl ether, ethylene glycol monophenyl ether, ethylene glycol monoallyl ether, diethylene glycol monophenyl ether, diethylene glycol monobutyl ether, propylene glycol mono Alkyl and aryl ethers of polyhydric alcohols such as butyl ether and tetraethylene glycol chlorophenyl ether, nonionic surfactants such as polyoxyethylene polyoxypropylene block copolymers, fluorosurfactants, ethanol, 2-propanol, etc. Although lower alcohols can be used, diethylene glycol monobutyl ether is particularly preferable.

  The surface tension of the recording liquid described above is preferably 30 mN / m or less. From the viewpoint of achieving both wettability with the recording material (corresponding to the paper 113) and droplet dropletization, the surface tension is 10 to 10. More preferably, it is 30 mN / m.

  The viscosity of the recording liquid described above is preferably 1.0 to 20.0 cP, and more preferably 3.0 to 10.0 cP from the viewpoint of ejection stability.

  Moreover, the pH of the recording liquid described above is preferably 3 to 11, and more preferably 6 to 10 from the viewpoint of preventing corrosion of the metal member in contact with the liquid.

  Further, the recording liquid described above may contain an antiseptic / antifungal agent. By containing an antiseptic / antifungal agent, the growth of bacteria can be suppressed, and the storage stability and image quality stability of the recording liquid can be improved. As this antiseptic and fungicide, benzotriazole, sodium dehydroacetate, sodium sorbate, 2-pyridinethiol-1-oxide sodium, isothiazoline-based compound, sodium benzoate, sodium pentachlorophenol and the like can be used.

  Further, the recording liquid described above may contain a rust inhibitor. By containing a rust preventive agent, it is possible to form a film on the metal surface in contact with the recording head or the like and prevent corrosion. As this rust preventive, for example, acidic sulfite, sodium thiosulfate, ammonium thiodiglycolate, diisopropylammonium nitrite, pentaerythritol tetranitrate, dicyclohexylammonium nitrite and the like can be used.

  Further, the recording liquid described above may contain an antioxidant. By containing an antioxidant, even when radical species that cause corrosion are generated, the antioxidant can be prevented by eliminating the radical species. Typical examples of the antioxidant include phenolic compounds and amine compounds. Examples of the phenolic compounds include hydroquinone and gallate compounds, 2,6-di-tert-butyl-p-cresol. , Stearyl-β- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 2,2′-methylenebis (4-methyl-6-tert-butylphenol), 2,2′-methylenebis (4- Ethyl-6-tert-butylphenol), 4,4′-thiobis (3-methyl-6-tert-butylphenol), 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) Butane, 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-4-hydroxybenzyl) ben , Tris (3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate, tetrakis [methylene-3 (3 ′, 5′-di-tert-butyl-4-hydroxyphenyl) propionate] methane, etc. Examples of the amine compounds include N, N′-diphenyl-p-phenylenediamine, phenyl-β-naphthylamine, phenyl-α-naphthylamine, and N, N′-β-naphthyl-p. -Phenylenediamine, N, N'-diphenylethylenediamine, phenothiazine, N, N'-di-sec-butyl-p-phenylenediamine, 4,4'-tetramethyl-diaminodiphenylmethane and the like. The amine compounds are typically sulfur compounds and phosphorus compounds, but the sulfur compounds are dilauryl thiodipropionate, distearyl thiodipropionate, lauryl stearyl thiodipropionate. , Dimyristyl thiodipropionate, distearyl β, β′-thiodibutyrate, 2-mercaptobenzimidazole, dilauryl sulfide, etc., and phosphorus compounds include triphenyl phosphite, trioctadecyl phosphite, Examples include tridecyl phosphite, trilauryl trithiophosphite, diphenylisodecyl phosphite, trinonylphenyl phosphite, distearyl pentaerythritol phosphite.

  Further, the recording liquid described above may contain a pH adjuster. Examples of the pH adjuster include hydroxides of alkali metal elements such as lithium hydroxide, sodium hydroxide, potassium hydroxide, ammonium hydroxide, quaternary ammonium hydroxide, quaternary phosphonium hydroxide, lithium carbonate. Further, alkali metal carbonates such as sodium carbonate and potassium carbonate, amines such as diethanolamine and triethanolamine, boric acid, hydrochloric acid, nitric acid, sulfuric acid, acetic acid and the like can be used.

Finally, an ink manufacturing method according to this embodiment will be described. Here, (1) production of a resin-coated black dispersion and (2) production of a recording liquid will be sequentially described.
(1) Production of resin-coated black dispersion a. Preparation of polymer solution First, the inside of a flask (volume 1 L) equipped with a mechanical stirrer, thermometer, nitrogen gas inlet tube, reflux tube and dropping funnel was sufficiently substituted with nitrogen gas, and then 11.2 g of styrene, 2. 8 g, 12.0 g of lauryl methacrylate, 4.0 g of polyethylene glycol methacrylate, 4.0 g of styrene macromer (manufactured by Toa Gosei Co., Ltd., trade name: AS-6) and 0.4 g of mercaptoethanol were charged and heated to 65 ° C. .

  Next, styrene 100.8 g, acrylic acid 25.2 g, lauryl methacrylate 108.0 g, polyethylene glycol methacrylate 36.0 g, hydroxyethyl methacrylate 60.0 g, styrene macromer (manufactured by Toa Gosei Co., Ltd., trade name: AS-6) A mixed solution of 36.0 g, mercaptoethanol 3.6 g, azobisdimethylvaleronitrile 2.4 g and methyl ethyl ketone 18 g was dropped into the flask over 2.5 hours.

  After completion of dropping, a mixed solution of 0.8 g of azobisdimethylvaleronitrile and 18 g of methyl ethyl ketone was dropped into the flask over 0.5 hours. After aging at 65 ° C. for 1 hour, 0.8 g of azobisdimethylvaleronitrile was added, and further aging was performed for 1 hour. After completion of the reaction, 364 g of methyl ethyl ketone was added to the flask to obtain 800 g of a polymer solution having a concentration of 50%.

Next, a part of the polymer solution was dried and measured by gel permeation chromatography (standard: polystyrene, solvent: tetrahydrofuran). The weight average molecular weight of the polymer was 15,000.
b. Preparation of resin-coated black dispersion 22.2 g of the polymer solution obtained in the above-described polymer solution preparation step a, 26.0 g of carbon black, 13.6 g of a 1 mol / L lithium hydroxide aqueous solution, 20 g of methyl ethyl ketone and ion-exchanged water After sufficiently stirring 30 g, the mixture was kneaded 20 times using a three-roll mill [manufactured by Noritake Co., Ltd., trade name: NR-84A]. The obtained paste was put into 200 g of ion-exchanged water and stirred sufficiently, and then methyl ethyl ketone and water were distilled off using an evaporator to obtain 160 g of a resin-coated black pigment dispersion having a solid content of 20.0% by weight. It was.
(2) Method for Producing Recording Liquid After mixing and stirring the components shown below, the liquid was filtered through a Teflon (registered trademark) filter (0.8 μm) to produce a recording liquid.

50 parts of resin-coated black pigment dispersion (black pigment solid content concentration 10 parts)
Glycerin 25 parts Surfactant (manufactured by NOF Corporation, Dispanol TOC) 1 part 2-pyrrolidone 2 parts Sodium dehydroacetate 0.2 part Sodium thiosulfate 0.2 part Antiseptic / antifungal agent (PROXEL LV (s) )) 0.4 part Antifoaming agent (manufactured by Shin-Etsu Chemical Co., Ltd., KM-72F) 0.1 part Remaining amount of ion-exchanged water The above mixture was further adjusted to pH 10.5 with a LiOH aqueous solution and used.

  According to such an embodiment of the present invention, the paper 113 (corresponding to a predetermined recording medium) is driven while the recording head 124 having the nozzles 31 aligned in the sub-scanning direction for each ink color is driven in the main scanning direction. In the serial type inkjet recording apparatus 1 in which the recording head 124 ejects at least two or more colors of ink onto the paper 113 and records an image, the nozzle array for each ink color is driven in the sub-scanning direction. When the length of the nozzle is 38 mm to 100 mm, and the nozzle row ejects ink for each ink color during non-recording, the idle ejection receiver 42 (empty ejection) having an absorber that receives and absorbs the ink droplets ejected idly. The empty discharge receiver 42 is provided with a light emitting unit 51 and a light receiving unit 52 (detecting the discharge state detecting unit) that detect the ink discharge state during empty discharge. By providing an equivalent to), the effect is expected that loss can be detected nozzles without lowering the printing speed. Here, by setting the length of the nozzle row for each ink color to 38 mm to 100 mm, the printing speed is improved by increasing the length of the recording head 124. In addition, by attaching the light emitting unit 51 and the light receiving unit 52 to the idle ejection receiver 42, a sequence for detecting missing nozzles is not required, and the ejection state of the nozzles is detected when idle ejection is performed. Therefore, a nozzle failure is detected while maintaining a predetermined printing speed. Furthermore, if wiping or the like is appropriately performed according to the detection state of nozzle omission, the quality of the printed image is stabilized.

  Further, according to this embodiment, at least one color or more of ink contains a pigment (for example, an organic pigment or an inorganic pigment) coated with a resin dispersant as a colorant, and the particle diameter of the pigment is 0.00. By setting the thickness to 01 μm to 0.03 μm, it is expected that the light resistance and the feathering are deteriorated and that the recording head 124 and the filter are prevented from being clogged.

  In addition, according to the present embodiment, the amount of the resin dispersant in the ink of at least one color is 0.5% by mass to 10% by mass, so that the viscosity of the ink is practical as an inkjet ink. The effect that it can be maintained within a certain range is also expected.

  As described above, in the ink jet recording apparatus according to the present invention, when the length of the nozzle row for each ink color is 38 mm to 100 mm and the nozzle row ejects ink for each ink color during non-printing, An empty discharge ink absorbing means (corresponding to an empty discharge receiver) having an absorber that receives and absorbs ink droplets is provided, and the empty discharge holding means has a discharge state for detecting the ink discharge state during empty discharge. By providing a detection means (corresponding to a light emitting part and a light receiving part), it is possible to detect the ejection state of the nozzles when idle ejection is performed without adding a sequence for nozzle detection. This has the effect of being able to detect missing nozzles while maintaining it, and is useful as an ink jet recording apparatus having a recording head for discharging ink liquid.

1 is a perspective view of an ink jet recording apparatus main body according to an embodiment of the present invention. 1 is a cross-sectional view of an ink jet recording apparatus according to an embodiment of the present invention. It is a perspective view of the negative pressure generating mechanism concerning one embodiment of the present invention. It is a figure explaining the structure of the maintenance apparatus which concerns on one Embodiment of this invention. It is a perspective view of the idle discharge receptacle which concerns on one Embodiment of this invention. FIG. 2 is an exploded perspective view of a recording head according to an embodiment of the invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inkjet recording device 31 Nozzle 40 Cap 41 Wiper 42 Empty discharge receptacle 43 Cap mechanism 44 Wiper mechanism 51 Light emission part 52 Light reception part 61 Base 62 FPC cable 63 Piezoelectric element 64 Frame 65 Vibration plate 66 Flow path plate 67 Nozzle plate 68 Cover 69 Ink Supply port 111 Main body 112 Printing mechanism section 113 Paper 114 Paper feed cassette 115 Manual feed tray 116 Paper discharge tray 121 Main guide rod 122 Sub guide rod 123 Carriage 124 Recording head 125 Negative pressure generating mechanism 127 Main scanning motor 128 Drive pulley 129 Drive pulley 130 Timing belt 131 Feed roller 132 Friction pad 133 Guide member 134 Conveying roller 135 Followed roller 136 Leading roller 137 Sub-scanning motor 13 Indicia copy receiving member 141 conveying roller 142 spur 143 paper discharge roller 144 spur 145, 146 guide member 147 maintainer

Claims (3)

While a recording head having nozzles aligned in the sub-scanning direction for each ink color is driven in the main scanning direction, a predetermined recording medium is driven in the sub-scanning direction, and the recording head performs predetermined recording of at least two colors of ink. A serial type ink jet recording apparatus configured to record an image by discharging to a medium,
The length of the nozzle row for each ink color is 38 mm to 100 mm, and the nozzle row has an absorber that receives and absorbs ink droplets that are ejected when the nozzle row ejects ink for each ink color during non-recording. An ink jet recording apparatus comprising: an empty discharge ink absorbing means, wherein the empty discharge holding means includes discharge state detecting means for detecting an ink discharge state during empty discharge. The inkjet recording apparatus according to claim 1, wherein
An ink jet recording apparatus characterized in that at least one color ink contains a pigment coated with a resin dispersant as a colorant, and the particle diameter of the pigment is 0.01 μm to 0.03 μm. . The inkjet recording apparatus according to claim 2,
An ink jet recording apparatus, wherein the amount of the resin dispersant in at least one color ink is 0.5% by mass to 10% by mass.

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