JP4813157B2 - Inkjet recording device - Google Patents

Description

  The present invention relates to an ink jet recording apparatus, and particularly to adjustment of landing positions of ink droplets of different droplet types such as large droplets and small droplets.

  An inkjet head in an inkjet recording apparatus used as an image forming apparatus such as a printer, a facsimile, a copying apparatus, or a plotter includes a nozzle that ejects ink droplets and a pressure generation chamber (pressure chamber, pressurized liquid chamber, liquid that communicates with the nozzle). Chamber, ink chamber, ink flow path, etc.) and actuator means (energy generating means) for generating energy for pressurizing ink in the pressure generating chamber. Also, the actuator means is driven to pressurize the ink in the pressure generating chamber and eject ink droplets from the nozzle openings. Ink-on-demand systems eject ink droplets only when recording is required. It has become mainstream.

  And it is divided roughly into several methods depending on the type of actuator means for ejecting ink droplets (recording liquid), and the piezo method and the bubble jet (registered trademark) method are generally well known. In the former, a part of the wall of the pressure generation chamber is a thin vibration plate, and a piezoelectric element as a pressure generation element is arranged corresponding to this, and the vibration plate is deformed by deformation of the piezoelectric element generated with voltage application. As a result, the pressure in the pressure generating chamber is changed to eject ink droplets. In the latter, a heating element is disposed in the liquid chamber, bubbles are generated by heating the heating element by energization, and ink droplets are ejected by the pressure of the bubbles.

  In addition, a vibration plate that forms a wall surface of the pressure generation chamber and an individual electrode outside the pressure generation chamber that is disposed to face the vibration plate are generated by applying an electric field between the vibration plate and the electrode. There has also been proposed an electrostatic type in which an ink droplet is ejected from a nozzle by changing the pressure / volume in the pressure generating chamber by deforming the diaphragm by an electrostatic force.

  By the way, in recent years, there has been an increasing demand for recording quality of ink jet recording apparatuses, and in the future, various printing performances such as high image quality, high resolution, and high speed will be required, and for these reasons, multi-gradation is required. ing.

  The recording operation of the ink jet recording apparatus is performed by an actuator that is supplied with a drive signal operating so as to pressurize the pressure generating chamber, and ink droplets are pushed out and ejected from the nozzle openings. The ejected ink droplets land on the recording paper in the order of ejection, and then form ink dots. By gathering a large number of these ink dots, an image is formed on the recording paper. By varying the number of ejected ink droplets in one printing cycle, the density of ink dots can be adjusted, thereby enabling multi-tone printing.

  However, when performing high-speed printing, the carriage speed of the ink jet head increases, so that the landing positions of a plurality of ink droplets ejected from the same nozzle are likely to be shifted in the carriage direction. For this reason, the ink dots that are normally formed in a circular shape become an oval shape that extends in the carriage direction due to the increase in speed, and as a result, the quality of the formed image decreases.

In order to cope with this, for example, Patent Document 1 includes a signal selection unit that selects a part from a plurality of pulse signals and supplies the selected signal to the actuator, and adjusts the potential and pulse height of the selected predetermined pulse signal. Thus, an ink jet head that can align the landing positions of ink droplets is disclosed.
JP 2004-017630 A

  However, in the invention of Patent Document 1, since a plurality of drive pulses constituting medium droplets and large droplets include a drive pulse whose potential on the front side pulse base is lower than the reference, the landing position of the ink droplet However, it is difficult to increase the volume of ink drops, that is, medium drops and large drops.

  Also, in order to achieve high image quality, when ejecting multiple droplet types such as large droplets, medium droplets, and small droplets, the large ink droplet volume needs to be 10 or more of the small ink droplet volume in the plain paper mode. May be. However, the larger the ink droplet volume, the higher the ejection speed, and the landing positions of different droplet types are not aligned on the paper surface.

  Accordingly, in order to solve the above-described problems, the present invention provides a recording paper surface that determines the landing positions of different ink droplets ejected corresponding to a plurality of drive pulses while ensuring the ink droplet volume necessary for high image quality. The aim is to improve the recording quality by aligning the above.

In order to achieve this object, the invention according to claim 1 is an ejection head having a plurality of nozzles for ejecting ink, a pressure chamber communicating with the nozzle, and a pressure generating element for changing the volume of the pressure chamber. And a drive signal generating means for generating a drive signal having a plurality of drive pulses for ejecting ink droplets within one printing cycle, and supplying the drive signal generated by the drive signal generating means, In an ink jet recording apparatus in which a pressure generating element is operated to eject ink droplets from the nozzles, the driving is set so that a plurality of ink droplets ejected from the nozzles are combined in flight within one printing cycle. The final drive pulse having a pulse and ejecting at least ink droplets in the drive pulse ejects one ink droplet from the nozzle within one printing cycle. When a smaller feed-through voltage draw meniscus than the drive pulse applied in the last simple pulling beating waveform than the reference potential prior to the driving pulse of the same printing cycle, and a potential higher than the reference potential It has a start-up voltage for ejecting up to ink droplets.

The invention described in this claim includes drive signal generation means for generating a drive signal having a plurality of drive pulses for ejecting ink droplets within one printing cycle. In the recording operation, ink droplets are ejected corresponding to individual drive pulses. When a plurality of ink droplets are ejected, the ink droplets are set to be combined into one ink droplet during flight. The Further, among the plurality of driving pulses, the final drive pulse for ejecting ink droplets in the same printing cycle is one print cycle within one ink droplet voltage pull than the drive pulses applied to the case of discharging from the nozzle And a rising voltage up to a potential higher than the reference potential. With this configuration, it is possible to align the landing positions of different types of ink droplets with different ejection speeds and to ensure the volume of the ink droplets without requiring special time. Ink droplets can be generated efficiently.

The invention of claim 2, in the ink jet recording apparatus according to claim 1, wherein the final drive pulse, and wherein the voltage pull than other drive pulses in the same printing cycle is small.

The invention of claim 3, wherein, in the ink jet recording apparatus according to claim 1 or 2, wherein the final drive pulse, before Symbol elevational Chiage voltage such that the same or substantially the same as the other drive pulse It is characterized by being set.

According to a fourth aspect of the present invention, in the ink jet recording apparatus according to any one of the first to third aspects, the drive signal has a fine drive pulse that vibrates a meniscus without ejecting ink droplets. It is characterized by.

According to a fifth aspect of the present invention, in the ink jet recording apparatus according to any one of the first to fourth aspects, the drive signal generating means selects a combination of the plurality of drive pulses in accordance with a print signal. It is characterized by doing.

According to a sixth aspect of the present invention, in the ink jet recording apparatus according to the fifth aspect , the drive signal generating unit selects the fine drive pulse.

According to a seventh aspect of the invention, in the ink jet recording apparatus according to the sixth aspect , the fine driving pulse is set to be positioned before the plurality of driving pulses.

According to an eighth aspect of the present invention, in the ink jet recording apparatus according to the seventh aspect , the fine drive pulse is a drive located immediately after the fine drive pulse when the natural vibration period of the pressure chamber is Tc. The interval from the pulse ejection timing is set to Tc ± 0.5 μs.

According to a ninth aspect of the present invention, in the ink jet recording apparatus according to any one of the first to eighth aspects, the ink viscosity is in the range of 5 mPa · s to 20 mPa · s.

Further, an invention according claim 10, in the ink jet recording apparatus according to claim 9, wherein the drive pulse is set when said ink viscosity is small is set to a voltage smaller, when the ink viscosity is large, a voltage greater It is characterized by that.

  According to the present invention, it is possible to arrange the landing positions of ink droplets of different droplet types ejected corresponding to a plurality of drive pulses on the recording paper surface while ensuring the ink droplet volume required for high image quality. Improvement of recording quality is realized.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  First, the overall structure of the ink jet recording apparatus according to this embodiment will be described. FIG. 1 is a perspective explanatory view of the ink jet recording apparatus according to the present embodiment as viewed from the front side.

  The ink jet recording apparatus according to this embodiment includes an apparatus main body 1, a paper feed tray 2 for loading paper mounted on the apparatus main body 1, and a detachable attachment to the apparatus main body 1 to record (form) an image. And a paper discharge tray 3 for stocking the printed paper. Further, a cartridge loading for loading an ink cartridge that protrudes from the front surface to the front side of the apparatus main body 1 and is lower than the upper surface is provided at one end side of the front surface of the apparatus main body 1 (side of the paper supply / discharge tray section). The cartridge loading unit 4 has an operation / display unit 5 provided with operation buttons and a display.

  The cartridge loading unit 14 includes a plurality of recording liquid cartridges each containing recording liquids (inks) of different colors, for example, black (K) ink, cyan (C) ink, magenta (M) ink, and yellow (Y) ink. An ink cartridge 10k, 10c, 10m, 10y (referred to as “ink cartridge 10” when colors are not distinguished) can be inserted and loaded from the front side of the apparatus main body 1 toward the rear side. A cartridge cover 6 that is a front cover that is opened when the ink cartridge 10 is attached / detached is provided on the front side of the ink cartridge 10 so as to be opened and closed. Further, the ink cartridges 10k, 10c, 10m, and 10y are configured to be loaded side by side in a vertical state.

  The cartridge cover 6 is a transparent or translucent member that can visually recognize the plurality of ink cartridges 10k, 10c, 10m, and 10y loaded in the cartridge loading unit 4 from the outside with the cover closed. Is formed. In addition, if the ink cartridges 10k, 10c, 10m, and 10y can be visually recognized from the outside, a part of the ink cartridges 10k, 10c, 10m, and 10y may be formed of a transparent or translucent member.

  Further, the operation / display unit 5 has the remaining amounts of the ink cartridges 10k, 10c, 10m, and 10y of each color at the arrangement positions corresponding to the mounting positions (arrangement positions) of the ink cartridges 10k, 10c, 10m, and 10y of the respective colors. A remaining amount display portion 11k, 11c, 11m, and 11y for each color for displaying the near end or the end is provided (“remaining amount display portion 11” when colors are not distinguished). Further, the operation / display unit 5 includes a power button 12, a paper feed / print resume button 13, and a cancel button 14.

  Next, the mechanism part of the ink jet recording apparatus of this embodiment will be described with reference to FIGS. FIG. 2 is a schematic configuration diagram for explaining the overall configuration of the mechanism unit, and FIG. 3 is a plan view for explaining a main part of the mechanism unit.

  The carriage 33 is slidably held in the main scanning direction by a guide rod 31 and a stay 32, which are guide members horizontally mounted on the left and right side plates 21A and 21B constituting the frame 21, and a main scanning motor not shown in FIG. Is moved and scanned in the direction indicated by the arrow (carriage main scanning direction).

  As described above, the carriage 33 includes the recording head 34 including four droplet discharge heads that discharge ink droplets of each color of yellow (Y), cyan (C), magenta (M), and black (K). A plurality of ink ejection openings are arranged in a direction crossing the main scanning direction, and are mounted with the ink droplet ejection direction facing downward.

  The droplet discharge head constituting the recording head 34 includes a piezoelectric actuator such as a piezoelectric element, a thermal actuator that uses a phase change caused by liquid film boiling using an electrothermal transducer such as a heating resistor, and a metal phase caused by a temperature change. A shape memory alloy actuator using a change, an electrostatic actuator using an electrostatic force, or the like can be used as pressure generating means for generating a pressure for discharging a droplet.

  Further, a driver IC is mounted on the recording head 34 and connected to a control unit (not shown) via a harness (flexible print cable) 22.

  The carriage 33 is equipped with a sub tank 35 for each color for supplying each color ink to the recording head 34. As described above, the sub tank 35 is supplied with ink of each color from the ink cartridge 10 of each color mounted in the cartridge loading unit 4 via the ink supply tube 36 of each color. The cartridge loading unit 4 is provided with a supply pump unit 24 for feeding ink in the ink cartridge 10, and the ink supply tube 36 is a rear plate 21 </ b> C that constitutes the frame 21 in the middle of turning. Is held by the locking member 25.

  On the other hand, as a paper feeding unit for feeding the papers 42 stacked on the paper stacking unit (pressure plate) 41 of the paper feed tray 2, a half-moon roller (feeding) that separates and feeds the papers 42 from the paper stacking unit 41 one by one. A separation pad 44 made of a material having a large friction coefficient is provided opposite to the sheet roller 43 and the sheet feeding roller 43, and the separation pad 44 is urged toward the sheet feeding roller 43 side.

  A guide member 45 for guiding the paper 42, a counter roller 46, a transport guide member 47, and a tip pressurization are fed to feed the paper 42 fed from the paper feed tray 2 to the lower side of the recording head 34. A pressing member 48 having a roller 49 and a conveying belt 51 serving as a conveying means for electrostatically attracting the fed paper 42 and conveying it at a position facing the recording head 34 are provided.

  The conveyor belt 51 is an endless belt, and is configured to wrap around the conveyor roller 52 and the tension roller 53 and circulate in the belt conveyance direction (sub-scanning direction). Further, the transport belt 51 is made of, for example, a surface layer that is a sheet adsorbing surface formed of a resin material (for example, ETFE pure material) having a pure thickness of about 40 μm that is not subjected to resistance control, and the same material as the surface layer made of carbon. It has a back layer (medium resistance layer, ground layer) that has been subjected to resistance control.

  In addition, a guide member 57 is disposed on the back side of the conveyance belt 51 so as to correspond to a printing area by the recording head 34. The guide member 57 maintains the high-precision flatness of the conveyor belt 51 by projecting toward the recording head 35 from the tangent line of the two rollers (the conveyor roller 52 and the tension roller 53) whose upper surface supports the conveyor belt 51. I am doing so. The transport belt 51 rotates in the belt transport direction of FIG. 3 when the transport roller 52 is rotationally driven via a drive belt by a sub-scanning motor (not shown).

  A charging roller 56 that is a charging unit for charging the surface of the transport belt 51 is provided. The charging roller 56 is disposed so as to contact the surface layer of the conveyor belt 51 and rotate following the rotation of the conveyor belt 51, and applies a predetermined pressing force to both ends of the shaft as a pressing force. The transport roller 52 also functions as an earth roller, and is in contact with the middle resistance layer (back layer) of the transport belt 51 and is grounded.

  Further, as a paper discharge unit for discharging the paper 42 recorded by the recording head 34, a separation claw 61, a paper discharge roller 62, and a paper discharge roller 63 for separating the paper 42 from the transport belt 51 are provided. A paper discharge tray 3 is provided below the paper roller 62. Here, the height from the sheet discharge roller 62 and the sheet discharge roller 63 to the sheet discharge tray 3 is increased to some extent in order to increase the amount that can be stocked in the sheet discharge tray 3.

  A duplex unit 71 is detachably mounted on the back surface of the apparatus body 1. The duplex unit 71 takes in the paper 42 returned by the reverse rotation of the transport belt 51, reverses it, and feeds it again between the counter roller 46 and the transport belt 51. The upper surface of the duplex unit 71 is a manual feed tray 72.

  Further, as shown in FIG. 3, a maintenance / recovery mechanism (subsystem) 81 for maintaining and recovering the nozzle state of the recording head 34 is disposed in the non-printing area on one side of the carriage 33 in the scanning direction. ing. The maintenance / recovery mechanism 81 has a cap member 82 for capping each nozzle surface of the recording head 34, a wiper blade 83 for wiping the nozzle surface, and idle discharge (discharge of droplets that do not contribute to image recording). An empty discharge receptacle 84 and the like for receiving the droplets discharged to the nozzle are provided. Similarly, a non-printing area on the other side in the scanning direction of the carriage 33 is similarly provided with an empty discharge receiver 85 for receiving droplets during empty discharge.

  In the ink jet recording apparatus configured as described above, the sheets 42 are separated and fed one by one from the sheet feeding tray 2, and the sheet 42 fed substantially vertically upward is guided by the guide member 45, and the conveyance belt 51. It is sandwiched between the counter roller 46 and conveyed, and further, the leading end is guided by the conveying guide member 47 and pressed against the conveying belt 51 by the leading end pressing roller 49, and the conveying direction is changed by approximately 90 °.

  At this time, a positive voltage output and a negative output are alternately repeated from the AC bias supply unit to the charging roller 56 by a control circuit (not shown), that is, a charging voltage pattern in which an alternating voltage is applied and the conveying belt 51 alternates. That is, plus and minus are alternately charged in a strip shape with a predetermined width in the sub-scanning direction of the circumferential direction. When the paper 42 is fed onto the conveyance belt 51 charged alternately with plus and minus, the paper 42 is attracted to the conveyance belt 51, and the paper 42 is conveyed in the sub-scanning direction by the circular movement of the conveyance belt 51.

  Therefore, by driving the recording head 34 according to the image signal while moving the carriage 33, ink droplets are ejected onto the stopped paper 42 to record one line, and after the paper 42 is conveyed by a predetermined amount, Record the next line. Upon receiving a recording end signal or a signal that the trailing edge of the paper 42 has reached the recording area, the recording operation is finished and the paper 42 is discharged onto the paper discharge tray 3.

  Next, an example of a droplet discharge head constituting the recording head 34 of the ink jet recording apparatus according to the present embodiment will be described with reference to FIGS. 4 is a cross-sectional explanatory diagram along the longitudinal direction of the liquid chamber of the head, and FIG. 5 is a cross-sectional explanatory diagram of the head in the lateral direction of the liquid chamber (arrangement direction of nozzles).

  The droplet discharge head includes, for example, a flow channel plate 101 formed by anisotropic etching of a single crystal silicon substrate, a vibration plate 102 formed by, for example, nickel electroforming bonded to the lower surface of the flow channel plate 101, The nozzle plate 103 joined to the upper surface of the road plate 101 is joined and laminated. In addition, the liquid droplet ejection head is common for supplying ink to the nozzle communication path 105, the liquid chamber 106, and the liquid chamber 106, which are channels through which the nozzles 104 that eject liquid droplets (ink droplets) communicate with each other. An ink supply port 109 and the like communicating with the liquid chamber 108 are formed.

  Also, two rows (only one row is shown in FIG. 4) of stacked piezoelectric elements as electromechanical conversion elements that are pressure generating means (actuator means) for deforming the diaphragm 102 to pressurize the ink in the liquid chamber 106. An element 121 and a base substrate 122 to which the piezoelectric element 121 is bonded and fixed are provided. Note that a column portion 123 is provided between the piezoelectric elements 121. The column portion 123 is a portion formed at the same time as the piezoelectric element 121 by dividing and processing the piezoelectric element member. However, since the drive voltage is not applied, the column portion 123 is a simple column.

  In addition, an FPC cable 124 for connecting to a drive circuit (drive IC) (not shown) is connected to the piezoelectric element 121.

  The peripheral portion of the diaphragm 102 is joined to the frame member 130, and the frame member 130 includes a through portion 131 that houses an actuator unit composed of the piezoelectric element 121, the base substrate 122, and the like, and a concave portion that becomes the common liquid chamber 108. And an ink supply hole 132 for supplying ink to the common liquid chamber 108 from the outside. The frame member 130 is formed by injection molding a thermosetting resin such as an epoxy resin or polyphenylene sulfite, for example.

  Here, the channel plate 101 is formed by, for example, subjecting a single crystal silicon substrate having a crystal plane orientation (110) to an anisotropic etching using an alkaline etching solution such as an aqueous potassium hydroxide solution (KOH), so that the nozzle communication path 105, Although a recess or a hole serving as the liquid chamber 106 is formed, the present invention is not limited to a single crystal silicon substrate, and other stainless steel substrates, photosensitive resins, and the like can also be used.

  The diaphragm 102 is formed of a nickel metal plate, and is manufactured by, for example, an electroforming method (electroforming method). In addition, a metal plate or a joining member between a metal and a resin plate is used. You can also. The piezoelectric element 121 and the column part 123 are joined to the diaphragm 102 with an adhesive, and the frame member 130 is further joined with an adhesive.

  In the nozzle plate 103, nozzles 104 having a diameter of 10 to 30 μm are formed corresponding to the respective liquid chambers 106, and are bonded to the flow path plate 101 with an adhesive. The nozzle plate 103 is obtained by forming a water repellent layer on the outermost surface of a nozzle forming member made of a metal member via a required layer.

  The piezoelectric element 121 is a stacked piezoelectric element (here, PZT) in which piezoelectric materials 151 and internal electrodes 152 are alternately stacked. An individual electrode 153 and a common electrode 154 are connected to each internal electrode 152 drawn to alternately different end faces of the piezoelectric element 121. In this embodiment, the ink in the liquid chamber 106 is pressurized using the displacement in the d33 direction as the piezoelectric direction of the piezoelectric element 121. However, the pressure in the d31 direction is used as the piezoelectric direction of the piezoelectric element 121. A configuration in which the ink in the liquid chamber 106 is pressurized is also possible. Alternatively, a structure in which one row of piezoelectric elements 121 is provided on one substrate 122 may be employed.

  In the droplet discharge head configured as described above, for example, by lowering the voltage applied to the piezoelectric element 121 from the reference potential, the piezoelectric element 121 contracts, and the diaphragm 102 descends to expand the volume of the liquid chamber 106. Thus, ink flows into the liquid chamber 106. Thereafter, the voltage applied to the piezoelectric element 121 is increased to extend the piezoelectric element 121 in the laminating direction, and the diaphragm 102 is deformed in the nozzle 104 direction to contract the volume / volume of the liquid chamber 106, whereby the liquid chamber The recording liquid in 106 is pressurized, and droplets of the recording liquid are ejected (jetted) from the nozzle 104.

  In addition, by returning the voltage applied to the piezoelectric element 121 to the reference potential, the diaphragm 102 is restored to the initial position, and the liquid chamber 106 expands to generate a negative pressure. The recording liquid is filled in 106. Therefore, after the vibration of the meniscus surface of the nozzle 104 is attenuated and stabilized, the operation proceeds to the next droplet discharge.

  Note that the driving method of the head is not limited to the above example (drawing-pushing), and it is also possible to perform striking, pushing, or the like depending on the direction of the drive waveform.

  Next, an outline of the control unit of the ink jet recording apparatus according to the present embodiment will be described with reference to FIG. This figure is an overall block diagram of the control unit.

  The control unit 200 includes a CPU 201 that controls the entire recording apparatus, a ROM 202 that stores programs executed by the CPU 201 and other fixed data, a RAM 203 that temporarily stores image data and the like, and a power supply for the recording apparatus. A non-volatile memory (NVRAM) 204 for holding data in between, an image processing for performing various signal processing and rearrangement on image data, and an ASIC 205 for processing input / output signals for controlling the entire apparatus. ing.

  The control unit 200 also has a host I / F 206 for transmitting and receiving data and signals to and from the host, which is an image processing apparatus (or data processing apparatus) such as a personal computer, and a drive for driving the recording head 34. A drive waveform generation unit 207 that generates a waveform, a head driver 208 that drives and controls the recording head 34, a main scanning motor drive unit 211 that drives the main scanning motor 212, and a sub-scan motor 214 that drives the sub-scanning motor 214. A scanning motor drive unit 213, an AC bias supply unit 215 that supplies an AC bias voltage to the charging roller 56, an I / O 216 for inputting detection signals from various sensors, and the like are provided.

  Here, the control unit 200 receives print data (print data) including image data from the host side such as an image processing device such as a personal computer, an image reading device such as an image scanner, and an imaging device such as a digital camera. Received from the host I / F 206 via the network.

  The CPU 201 reads and analyzes the print data in the reception buffer included in the host I / F 206, performs necessary image processing, data rearrangement processing, and the like in the ASIC 205 and transfers the image data to the head driver 208. . The dot pattern data for image output may be generated by storing font data in the ROM 202, for example, or the image data is developed into bitmap data by a host-side printer driver and transferred to this apparatus. You may do it.

  The drive waveform generation unit 207 is configured by a D / A converter that performs D / A conversion on the drive pulse pattern data, and is configured by one drive pulse (drive signal) or a plurality of drive pulses (drive signal). The waveform is output to the head driver 208.

  The head driver 208 selectively selects drive pulses constituting the drive waveform supplied from the drive waveform generation unit 207 based on image data (dot pattern data) corresponding to one line of the recording head 34 input serially. The recording head 34 is driven by being applied to the pressure generating means (piezoelectric element 121) of the recording head 34.

  Next, an example of ink (recording liquid, hereinafter referred to as “main ink”) used in the ink jet recording apparatus of the present embodiment will be described.

This ink is composed of the following (1) to (10), and a pigment is used as a colorant for printing, and an essential component is a solvent for decomposing and dispersing the pigment. Further, wetting agents, surfactants, emulsions, preservatives, pH adjusters are used as additives. The reason why the humectant 1 and the humectant 2 are mixed is to make use of the characteristics of the humectant and to easily adjust the viscosity.
(1) Pigment (self-dispersing pigment) 6 wt% or more (2) Wetting agent 1
(3) Wetting agent 2
(4) Soluble organic solvent (5) Nion or nonionic surfactant (6) Polyol or glycol ether having 8 or more carbon atoms (7) Emulsion (8) Preservative (9) pH adjuster (10) Pure water Each ink component will be described more specifically.

  Regarding the pigment of (1), inorganic pigments and organic pigments can be used without any particular limitation. As the inorganic pigment, in addition to titanium oxide and iron oxide, carbon black produced by a known method such as a contact method, a furnace method, or a thermal method can be used. Organic pigments include azo pigments (including azo lakes, insoluble azo pigments, condensed azo pigments, chelate azo pigments), polycyclic pigments (for example, phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments). , Dioxazine pigments, thioindigo pigments, isoindolinone pigments, quinofullerone pigments, etc.), dye chelates (for example, basic dye chelate, acidic dye chelate, etc.), nitro pigments, nitroso pigments, aniline black, and the like.

  Of these pigments, those having good affinity with water are preferably used. The particle diameter of the pigment is preferably 0.05 μm to 10 μm, more preferably 1 μm or less, and most preferably 0.16 μm or less. The amount of pigment added as a colorant in the ink is preferably about 6 to 20 wt%, more preferably about 8 to 12 wt%.

  Specific examples of pigments preferably used in the ink include the following. For black, carbon black (CI Pigment Black 7) such as furnace black, lamp black, acetylene black, channel black, or metal such as copper, iron (CI Pigment Black 11), titanium oxide And organic pigments such as aniline black (CI Pigment Black 1).

  For color, C.I. I. Pigment Yellow 1 (Fast Yellow G), 3, 12 (Disazo Yellow AAA), 13, 14, 17, 24, 34, 35, 37, 42 (Yellow Iron Oxide), 53, 55, 81, 83 (Disazo Yellow HR) ), 95, 97, 98, 100, 101, 104, 408, 109, 110, 117, 120, 138, 153, C.I. I. Pigment orange 5, 13, 16, 17, 36, 43, 51, C.I. I. Pigment Red 1, 2, 3, 5, 17, 22 (Brilliant First Scarlet), 23, 31, 38, 48: 2 (Permanent Red 2B (Ba)), 48: 2 (Permanent Red 2B (Ca)), 48: 3 (Permanent Red 2B (Sr)), 48: 4 (Permanent Red 2B (Mn)), 49: 1, 52: 2, 53: 1, 57: 1 (Brilliant Carmine 6B), 60: 1, 63 : 1, 63: 2, 64: 1, 81 (Rhodamine 6G rake), 83, 88, 101 (Bengara), 104, 105, 106, 108 (Cadmium red), 112, 114, 122 (Quinacridone magenta), 123 146, 149, 166, 168, 170, 172, 177, 178, 179, 185, 190, 193, 209, 219, CI Pigment Violet 1 (Rhodamine Lake), 3, 5: 1, 16, 19, 23, 38, CI Pigment Blue 1, 2, 15 (Phthalocyanine Blue R), 15: 1, 15: 2, 15: 3 (Phthalocyanine Blue) E), 16, 17: 1, 56, 60, 63, C.I. I. Pigment green 1, 4, 7, 8, 10, 17, 18, 36, and the like.

  In addition, the surface of pigment (for example, carbon) can be dispersed in water by adding a functional group such as a sulfone group or a carboxyl group to the surface of the pigment (for example, carbon) that has been treated with resin to disperse in water. The processed pigment etc. which were made can be used. Further, the pigment may be included in the microcapsule so that the pigment can be dispersed in water.

  According to a preferred embodiment of the present ink, the pigment for black ink is preferably added to the ink as a pigment dispersion obtained by dispersing the pigment in an aqueous medium with a dispersant. As a preferable dispersing agent, a known dispersion used for preparing a conventionally known pigment dispersion can be used.

  Moreover, as a dispersion liquid, the following are mentioned, for example. Polyacrylic acid, polymethacrylic acid, acrylic acid-acrylonitrile copolymer, vinyl acetate-acrylic acid ester copolymer, acrylic acid-acrylic acid alkyl ester copolymer, styrene-acrylic acid copolymer, styrene-methacrylic acid copolymer Polymer, styrene-acrylic acid-alkyl acrylate ester copolymer, styrene-methacrylic acid-alkyl acrylate copolymer, styrene-α-methylstyrene-acrylic acid copolymer, styrene-α-methylstyrene-acrylic Acid copolymer-alkyl acrylate ester copolymer, styrene-maleic acid copolymer, vinyl naphthalene-maleic acid copolymer, vinyl acetate-ethylene copolymer, vinyl acetate-fatty acid vinyl ethylene copolymer, vinyl acetate -Maleate ester copolymer, vinyl acetate- Examples include crotonic acid copolymers and vinyl acetate-acrylic acid copolymers.

  According to a preferred embodiment of the ink, these copolymers preferably have a weight average molecular weight of 3,000 to 50,000, more preferably 5,000 to 30,000, and most preferably 7,000 to 7,000. 15,000. The addition amount of the dispersant may be appropriately added within a range in which the pigment is stably dispersed and the other effects of the present invention are not lost. The dispersant is preferably in the range of 1: 0.06 to 1: 3, more preferably in the range of 1: 0.125 to 1: 3.

  The pigment used for the colorant is a particle having a particle size of 0.05 μm to 0.16 μm or less, containing 6 wt% to 20 wt% with respect to the total weight of the recording ink, and is dispersed in water by a dispersant. The dispersant is a polymer dispersant having a molecular weight of 5,000 to 100,000. When at least one water-soluble organic solvent is a pyrrolidone derivative, particularly 2-pyrrolidone, the image quality is improved.

  Regarding the wetting agents 1 and 2 and the water-soluble organic solvent (2) to (4), in the case of the present ink, water is used as a liquid medium in the ink. For example, the following water-soluble organic solvents are used for the purpose of preventing the drying and for improving the dissolution stability. A plurality of these water-soluble organic solvents may be used in combination.

  Specific examples of the wetting agent and the water-soluble organic solvent include the following. Ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, tetraethylene glycol, hexylene glycol, polyethylene glycol, polypropylene glycol, 1,5-pentanediol, 1,6-hexanediol, glycerol, Polyhydric alcohols such as 1,2,6-hexanetriol, 1,2,4-butanetriol, 1,2,3-butanetriol, petriol; ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether , Diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether Polyhydric alcohol alkyl ethers such as propylene glycol monoethyl ether; Polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether; 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl Nitrogen-containing heterocyclic compounds such as 2-pyrrolidone, 1,3-dimethylimidazolidinone, ε-caprolactam, γ-butyrolactone; amides such as formamide, N-methylformamide, N, N-dimethylformamide; monoethanol Amines such as amine, diethanolamine, triethanolamine, monoethylamine, diethylamine and triethylamine; sulfur-containing compounds such as dimethyl sulfoxide, sulfolane and thiodiethanol; propylene carbonate Over bets is ethylene carbonate.

  Among these organic solvents, diethylene glycol, thiodiethanol, polyethylene glycol 200 to 600, triethylene glycol, glycerol, 1,2,6-hexanetriol, 1,2,4-butanetriol, petriol, 1,5-pentane Diol, 2-pyrrolidone and N-methyl-2-pyrrolidone are preferred. These provide excellent effects on solubility and prevention of jetting property defects due to water evaporation.

  The other wetting agent preferably contains sugar. Examples of saccharides include monosaccharides, disaccharides, oligosaccharides (including trisaccharides and tetrasaccharides) and polysaccharides, preferably glucose, mannose, fructose, ribose, xylose, arabinose, galactose, maltose, cellobiose, Examples include lactose, sucrose, trehalose, maltotriose and the like. Here, the polysaccharide means a saccharide in a broad sense and is used to include a substance that exists widely in nature, such as α-cyclodextrin and cellulose.

Moreover, as derivatives of these saccharides, reducing sugars of the saccharides described above (for example, sugar alcohol (represented by the general formula HOCH ₂ (CHOH) nCH ₂ OH (where n = 2 to 5 represents an integer)) , Oxidized sugars (for example, aldonic acid, uronic acid, etc.), amino acids, thioic acids, etc. In particular, sugar alcohols are preferred, and specific examples include maltitol, sorbit, etc. The range of 0.1 to 40 wt%, preferably 0.5 to 30 wt% of the ink composition is appropriate.

  The surfactant of (5) is not particularly limited, but examples of the anionic surfactant include polyoxyethylene alkyl ether acetate, dodecylbenzene sulfonate, laurate, polyoxyethylene alkyl ether sulfate. And the like. Nonionic surfactants include, for example, polyoxyethylene alkyl ether, polyoxyethylene alkyl ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene alkyl phenyl ether, polyoxyethylene alkylamine, polyoxyethylene alkylamide, and the like. Can be mentioned. The surfactants can be used alone or in admixture of two or more.

  The surface tension in this ink is an index indicating the permeability to paper. In particular, the surface tension indicates the dynamic surface tension in a short time of 1 second or less after the surface is formed, and the static surface tension measured by the saturation time is Different. As a measuring method, any conventionally known method (for example, described in JP-A-63-131237) can be used as long as it can measure a dynamic surface tension of 1 second or less. It measured using the Wilhelmy type suspension plate type surface tension meter. When the surface tension value is preferably 40 mJ / m 2 or less, more preferably 35 mJ / m 2 or less, excellent fixing properties and drying properties can be obtained.

Regarding the polyol or glycol ether having 8 or more carbon atoms of (6), at least a water-soluble polyol or glycol ether having a solubility of less than 0.1 to 4.5 wt% in water at 25 ° C. By adding either 0.1 to 10.0 wt% of the total amount of the recording ink, the wettability of the ink to the thermal element is improved, and even with a small addition amount, ejection stability and frequency stability are improved. Was found to be obtained.
(A) 2-ethyl-1,3-hexanediol Solubility: 4.2% (20 ° C.)
(B) 2,2,4-trimethyl-1,3-pentanediol Solubility: 2.0% (25 ° C.)
A penetrant having a solubility of less than 0.1-4.5 wt% in water at 25 ° C. has the advantage of very high permeability instead of low solubility. Therefore, an ink having a very high permeability by combining a penetrant having a solubility of less than 0.1 to 4.5 wt% in water at 25 ° C. with another solvent or another surfactant. It can be produced.

  (7) It is preferable that a resin emulsion is added to the ink. The resin emulsion means an emulsion in which the continuous phase is water and the dispersed phase is the following resin component. Examples of the resin component of the dispersed phase include acrylic resins, vinyl acetate resins, styrene-butadiene resins, vinyl chloride resins, acrylic-styrene resins, butadiene resins, and styrene resins.

  According to a preferred embodiment of the present ink, this resin is preferably a polymer having both a hydrophilic part and a hydrophobic part. The particle size of these resin components is not particularly limited as long as an emulsion is formed, but is preferably about 150 nm or less, more preferably about 5 to 100 nm.

  These resin emulsions can be obtained by mixing resin particles in water, optionally with a surfactant. For example, an acrylic resin or styrene-acrylic resin emulsion can be obtained by adding (meth) acrylic acid ester or styrene, (meth) acrylic acid ester, and optionally (meth) acrylic acid ester, and a surfactant in water. It can be obtained by mixing. The mixing ratio of the resin component and the surfactant is usually preferably about 10: 1 to 5: 1. When the amount of the surfactant used is less than the above range, it is difficult to form an emulsion, and when it exceeds the above range, the water resistance of the ink tends to be lowered or the penetrability tends to deteriorate.

  The ratio of the resin as the dispersed phase component of the emulsion and water is 60 to 400 parts by weight, preferably 100 to 200 parts by weight with respect to 100 parts by weight of the resin. Commercially available resin emulsions include Microgel E-1002, E-5002 (styrene-acrylic resin emulsion, manufactured by Nippon Paint Co., Ltd.), Boncoat 4001 (acrylic resin emulsion, manufactured by Dainippon Ink & Chemicals, Inc.), Boncoat 5454 (styrene-acrylic resin emulsion, manufactured by Dainippon Ink & Chemicals, Inc.), SAE-1014 (styrene-acrylic resin emulsion, manufactured by Nippon Zeon Co., Ltd.), Cybinol SK-200 (acrylic resin emulsion, Seiden Chemical Co., Ltd.) Etc.). The ink preferably contains a resin emulsion such that the resin component is 0.1 to 40 wt% of the ink, more preferably 1 to 25 wt%.

  As described above, the resin emulsion has the property of thickening and aggregating, has the effect of suppressing the penetration of the coloring component, and further promoting the fixing to the recording material. Further, depending on the type of resin emulsion, a film is formed on the recording material, and the printed material has an effect of improving the abrasion resistance.

  (8)-(10) In addition to the colorant, solvent, and surfactant, conventionally known additives can be added to the ink. For example, as an antiseptic / antifungal agent, sodium dehydroacetate, sodium sorbate, sodium 2-pyridinethiol-1-oxide, sodium benzoate, sodium pentachlorophenol and the like can be used.

  As the pH adjuster, any substance can be used as long as the pH can be adjusted to 7 or more without adversely affecting the ink to be prepared. Examples thereof include amines such as diethanolamine and triethanolamine, hydroxides of alkali metal elements such as lithium hydroxide, sodium hydroxide and potassium hydroxide, ammonium hydroxide, quaternary ammonium hydroxide, and quaternary phosphonium. Examples thereof include carbonates of alkali metals such as hydroxide, lithium carbonate, sodium carbonate, and potassium carbonate.

  Examples of the chelating reagent include sodium ethylenediaminetetraacetate, sodium nitrilotriacetate, sodium hydroxyethylethylenediaminetriacetate, sodium diethylenetriaminepentaacetate, sodium uramil diacetate, and the like.

  Examples of the rust inhibitor include acidic sulfite, sodium thiosulfate, ammonium thiodiglycolate, diisopropylammonium nitrite, pentaerythritol tetranitrate, and dicyclohexylammonium nitrite.

  Next, drive signals generated in the ink jet recording apparatus of the present embodiment will be described with reference to FIGS.

  This drive signal has a plurality or a single drive pulse in one printing cycle, and a plurality of drive pulses or a single drive pulse of different combinations are selected according to the print signal. FIG. 7 is a diagram illustrating an example of the relationship between the print signal and the drive signal.

  There are mainly three types of waveforms, a small droplet waveform, a medium droplet waveform, and a large droplet waveform, and are generated as a drive signal according to a print signal by a combination of eight drive pulses P1 to P8. For example, when the print signal Ps1 is received, a driving pulse having a combination of P2 to P8 is selected as a large droplet waveform and input to the head. In the case of the print signal Ps2, the combination drive pulse P4 to P6 is selected as the medium droplet waveform, and in the case of the print signal Ps3, the drive pulse P1 is selected as the small droplet waveform and input to the head. The In addition to the above three types of waveforms, there is a fine drive waveform. When the print signal Ps4 is received, the drive pulse (fine drive pulse) of Ps2 is selected and input to the head.

  FIG. 8 is a drive signal diagram selected as a large droplet waveform. In the figure, it is composed of seven drive pulses including a fine drive pulse P2, and includes drive pulses P4 to P6 as medium droplet waveforms. Since the fine drive pulse is a drive pulse that vibrates the meniscus without ejecting ink droplets, the ink droplets ejected by each of the drive pulses P3 to P8 are combined into a large droplet during flight. That is, the first ink droplet is ejected by P3, the second, third, and fourth ink droplets are ejected by P4, P5, and P6, and the fifth and sixth ink droplets are ejected by P7 and P8. These ink droplets coalesce during the flight and become large-diameter ink droplets that land on the recording paper.

  Here, the final drive pulse P8 among the plurality of drive pulses is not a simple beat waveform such as the drive pulses P4 and P5 but a pulse with a reduced pull-in voltage. This is because if the drive pulse P8 has a simple striking waveform like the other drive pulses, the ink droplet velocity becomes too large, and the ink droplet velocity is relatively large because it is composed of one pulse like a small droplet. This is because there is a risk of shifting from the landing position of another difficult drop type. In this way, by reducing the pull-in voltage, the meniscus pull-in is reduced and the speed of the ink droplet ejected at the end is suppressed. However, by simply reducing the pull-in voltage, the necessary ink droplet volume is ejected. Therefore, it is necessary to make the start-up voltage large enough to eject the necessary ink droplet volume.

  In the drive pulses P3 and P6, the pull-in voltage is reduced and the rising voltage is maintained for the purpose of adjusting the ink droplet speed and accumulating the ink droplet volume.

  FIG. 9 is a drive signal diagram selected as the medium droplet waveform. The figure is composed of three drive pulses P4, P5 and P6. First, the first droplet is ejected by the driving pulse P4, then the second droplet is ejected by the driving pulse P5, and the third droplet is ejected by the driving pulse P6. To land on. Assuming that the natural vibration period of the pressure chamber is Tc, the interval between the ejection timings of the drive pulses P4 and P5 is desirably 2Tc ± 0.5 μs.

  The final drive pulse is not a simple beat waveform, but has a small pull-in voltage, as in the case of a large drop waveform. In other words, the drive pulses P4 and P5 have a simple strike waveform. However, if the drive pulse P6 has the same simple strike waveform, the ink droplet velocity becomes too large, and the ink droplet velocity becomes relatively large. Since there is a possibility that it is difficult to deviate from the landing position of another difficult drop type, the driving pulse P6 reduces the pulling-in voltage to reduce the pulling-in of the meniscus and suppresses the ink drop speed of the third drop. However, the startup voltage is not reduced in order to increase the necessary ink droplet volume.

  FIG. 10 is a drive signal diagram selected as the droplet waveform. Here, the ink droplets are ejected as small droplets by the drive pulse P1, but in order to increase the speed rather than suppressing the ink droplet speed, the pull-in and rise voltages are set larger than those of the other drive pulses. ing. This is because an ink droplet composed of one pulse is less likely to have a relatively high ink droplet velocity and may not align with the landing positions of other droplet types.

  FIG. 11 is a drive signal diagram selected as the fine drive waveform. The fine driving waveform is to vibrate the meniscus without ejecting ink droplets in order to prevent the meniscus from drying. The fine driving waveform is input to the head mainly in the non-printing area.

  Note that the fine driving pulse P2 is included in the large droplet waveform described above, but this uses the fine driving pulse as one of the driving pulses constituting the large droplet, and shortens the driving cycle ( Speed). Furthermore, by setting the interval between the ejection timings of the fine driving pulse P2 and the driving pulse P3 to Tc ± 0.5 μs, it is possible to efficiently accumulate the volume of ink droplets ejected by the driving pulse P3.

  FIG. 12 is a drive signal diagram when the ink viscosity is 5 mPa · s, 10 mPa · s, and 20 mPa · s. When the ink viscosity is low, the drive pulse voltage is reduced, and when the ink viscosity is high, the drive pulse voltage is increased to keep the ink droplet velocity and volume constant regardless of the ink viscosity (temperature). Can be discharged in a state. Further, the driving pulse P2 can vibrate the meniscus without ejecting ink droplets by selecting a peak value according to the ink viscosity.

  According to the above embodiment, it is possible to align the landing positions on the paper surface of a large droplet or medium droplet composed of a plurality of ink droplets and a small droplet composed of one droplet.

  Further, according to the above-described embodiment, a plurality of driving pulses of different combinations such as large droplets and medium droplets can be selected in accordance with the print signal within one printing cycle, so that the driving cycle is shortened, that is, Speeding up is possible.

  Further, according to the above embodiment, in the non-printing region, the fine driving pulse that only vibrates the meniscus without ejecting ink droplets is provided, so that nozzle clogging or ejection abnormality due to meniscus drying is prevented. Can be prevented.

  In addition, according to the above-described embodiment, the fine driving pulse is used not only to prevent meniscus drying but also as a constituent pulse of a large droplet, so that the droplet volume of the large droplet can be efficiently accumulated. it can.

  Further, according to the above-described embodiment, a plurality of drive pulses are generated by combining droplets that eject ink droplets such as large droplets and medium droplets and fine drive pulses that are not ejected in accordance with a print signal within one printing cycle. Since the selection can be made, the drive cycle can be shortened, that is, the speed can be increased.

  Further, according to the above-described embodiment, stable ink droplet ejection and nozzle maintenance can be performed for ink having a very high viscosity and ink having a low viscosity.

  The above-described embodiment is a preferred embodiment of the present invention, and the scope of the present invention is not limited to the above-described embodiment alone, and various modifications are made without departing from the gist of the present invention. Implementation is possible.

1 is a perspective view of an ink jet recording apparatus according to an embodiment of the present invention. 1 is a cross-sectional view illustrating a configuration of an ink jet recording apparatus according to an embodiment of the present invention. 1 is a plan view illustrating a configuration of an ink jet recording apparatus according to an embodiment of the present invention. 2 is a cross-sectional view illustrating a configuration of a droplet discharge head of the ink jet recording apparatus according to the embodiment of the present invention. FIG. 2 is a cross-sectional view illustrating a configuration of a droplet discharge head of the ink jet recording apparatus according to the embodiment of the present invention. FIG. FIG. 3 is a block diagram illustrating a configuration of a control unit of the inkjet recording apparatus according to the embodiment of the present invention. It is a drive signal diagram in the ink jet recording apparatus according to the embodiment of the present invention. It is a drive signal diagram in the ink jet recording apparatus according to the embodiment of the present invention. It is a drive signal diagram in the ink jet recording apparatus according to the embodiment of the present invention. It is a drive signal diagram in the ink jet recording apparatus according to the embodiment of the present invention. It is a drive signal diagram in the ink jet recording apparatus according to the embodiment of the present invention. It is a drive signal diagram in the ink jet recording apparatus according to the embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Apparatus main body 2 Paper feed tray 3 Paper discharge tray 4 Cartridge loading part 5 Operation / display part 6 Cartridge cover 10k, 10c, 10m, 10y Ink cartridge 11k, 11c, 11m, 11y Remaining quantity display part 12 Power button 13 Paper feed / print Resume button 14 Cancel button 33 Carriage 34 Recording head 35 Sub tank 36 Ink supply tube 81 Maintenance / recovery mechanism 82 Cap member 83 Wiper blade 84,85 Empty discharge receptacle 101 Flow path plate 102 Vibration plate 103 Nozzle plate 104 Nozzle 105 Nozzle communication path 106 Liquid Chamber 108 Common liquid chamber 109 Ink supply port 121 Stacked piezoelectric element 122 Base substrate 124 Supporting part 130 Frame member 131 Through part 132 Ink supply hole 151 Piezoelectric material 152 Internal electrode 153 Individually The pole 154 common electrode

Claims (10)

A plurality of nozzles for ejecting ink, a pressure chamber communicating with the nozzle, an ejection head having a pressure generating element for changing the volume of the pressure chamber, and a plurality of drive pulses for ejecting ink droplets within one printing cycle Drive signal generating means for generating a drive signal included in
In the ink jet recording apparatus, wherein the driving signal generated by the driving signal generating means is supplied to operate the pressure generating element to discharge ink droplets from the nozzle.
Having a drive pulse set so that a plurality of ink droplets ejected from the nozzle within one printing cycle merge during flight;
The final drive pulse for ejecting at least ink droplets in the drive pulse is a reference preceding the final drive pulse within the same printing cycle when one ink droplet is ejected from the nozzle within one printing cycle. Ink jet recording, characterized in that a pull-in voltage for pulling a meniscus is smaller than a drive pulse applied with a simple beat waveform than a potential and a rising voltage for discharging ink droplets to a potential higher than the reference potential apparatus.   The inkjet recording apparatus according to claim 1, wherein the final drive pulse has a smaller pull-in voltage than other drive pulses in the same printing cycle.   3. The ink jet recording apparatus according to claim 1, wherein the final drive pulse is set so that the rising voltage is the same as or substantially the same as another drive pulse. 4.   4. The ink jet recording apparatus according to claim 1, wherein the drive signal includes a fine drive pulse that vibrates a meniscus without ejecting an ink droplet. 5.   5. The ink jet recording apparatus according to claim 1, wherein the drive signal generation unit selects a combination of the plurality of drive pulses in accordance with a print signal. 6.   6. The ink jet recording apparatus according to claim 5, wherein the drive signal generating unit selects the fine drive pulse.   The inkjet recording apparatus according to claim 6, wherein the fine drive pulse is set to be positioned before the plurality of drive pulses.   The fine drive pulse is characterized in that when the natural vibration period of the pressure chamber is Tc, the interval from the ejection timing of the drive pulse located immediately after the fine drive pulse is set to Tc ± 0.5 μs. The ink jet recording apparatus according to claim 7.   The ink jet recording apparatus according to claim 1, wherein the ink viscosity is in a range of 5 mPa · s to 20 mPa · s.   10. The ink jet recording apparatus according to claim 9, wherein the drive pulse is set to have a small voltage when the ink viscosity is small and set to a large voltage when the ink viscosity is large.

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