JP2861041B2 - Recording device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording device such as a printer using an electric field curtain.

(Prior art)

Conventionally, as one embodiment of a recording apparatus, a bubble jet type ink jet printer head provided with a heating resistor near an opening of a nozzle made of an insulating material is disclosed in
It is proposed in 59936.

In this printer head, bubbles are formed in the ink in the nozzle by applying an electric signal corresponding to the image information to the heating resistor element, and the ink in the vicinity of the nozzle opening is formed based on the volume change of the bubble. The ink is ejected and flies in the air, and is recorded on a recording medium. .

[Problems to be solved by the invention]

However, in the above-described printer head, the ink ejection / flying depends only on the volume change of the bubble.
Flight is impossible. In other words, it is not possible to apply a slight voltage and current to eject and fly ink,
There is a problem that the gradation is inferior because the control is difficult.

[Means for solving the problem]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problem of liquid, and the invention according to claim 1 has an ink chamber for accommodating a liquid ink, and serves as an ink ejection port from the ink chamber. A container provided with an orifice, an electric field forming means for applying an alternating electric field to the ink contained in the container in the vicinity of the orifice to apply an electric field curtain force to the ink toward the orifice, and moving the ink in the ink chamber in the orifice direction. And a providing means for applying a pushing force, wherein the ink is ejected from the orifice by a combined force of the pushing force by the applying means and the electric field curtain force by the electric field forming means.

According to a second aspect of the present invention, in the recording apparatus according to the first aspect, there is provided a control unit that controls at least one of the electric field forming unit and the applying unit in multiple stages according to an image signal. It is a recording device.

Further, according to a third aspect of the present invention, in the recording apparatus according to the first aspect, the vicinity of the orifice of the container is subjected to a sparse ink treatment.

[Action]

The recording apparatus according to claim 1 having the above configuration,
The liquid ink in the ink chamber is pushed in the direction of the orifice by the applying means, and the ink is ejected and flies from the orifice by the combined force with the electric field curtain force by the electric field forming means. Here, the ink in the vicinity of the orifice is in a dynamic state due to the pushing force of the applying means and is in a state where it is easily ejected from the orifice. Therefore, the ink is ejected even by a slight electric field curtain force.

Further, in the recording apparatus according to the second aspect, at least one of the electric field forming unit and the applying unit is controlled in multiple stages by a control unit in accordance with an image signal, so that the ink ejection amount can be controlled.

Further, in the recording apparatus according to the third aspect, the vicinity of the orifice of the container is subjected to an ink-phobic treatment.

〔Example〕

Hereinafter, specific examples of the recording apparatus having the above configuration,
This will be described with reference to the accompanying drawings.

A. First Embodiment (See FIGS. 1 to 3) In the drawing, reference numeral 1 denotes a print head of a recording apparatus, 2 denotes an upper panel, 3 denotes a lower panel, and both the upper panel 2 and the lower panel 3 are insulating base materials. It is composed of As shown in FIG. 3, a plurality of slits 4 are formed in the lower panel 3, and a nozzle 5 is formed corresponding to the slit 4 by overlapping the upper panel 2 and the lower panel 3, An orifice 6 is formed at one end of the nozzle 5. Panel 2, 3
Are provided with individual electrodes 7 and 8 in the vicinity of the orifice 6 so as to face each other. On the opposite side of the individual electrodes 7 and 8 from the orifice 6, current-carrying electrodes 9 and 10 are attached to face each other. Note that the individual electrodes 7 of the upper panel 2 are covered with an insulating protective film 11 at portions facing the nozzles 5. The outer surfaces of the upper panel 2 and the lower panel 3 are doubly covered by an insulating protection 12 and an ink-phobic insulating protection film 13. In particular, the outer (surface) insulating protection film 13 It extends to the tip of.

In the print head 1 having the above configuration, the ink In is supplied to each nozzle 5 from an unillustrated ink tank. As the ink In, a high-resistance ink in which charged color particles charged in advance are dispersed, or a chargeable hot-melt ink is used. The chargeable ink includes charge injection charge of electrons and hole ions from electrodes, induced charge in an electrostatic field, contact charge by contact of wall materials, electrodes, etc., charge by polarization inside the ink, and polar groups. It refers to various types of ink charged by charging or the like due to having.

In the printer head 1 having the above configuration, the control device
When an alternating voltage or a pulse voltage is applied from the power supply 22 to the energizing electrodes 9 and 10 based on the signal from the 21, the ink In located between the energizing electrodes 9 and 10 is energized and heated to generate bubbles 23.

An alternating voltage is applied from the alternating power supply 20 to the individual electrodes 7 of the upper panel 2 in synchronization with the generation of the bubbles 23, and the control device 21 sends the lower panel 3 in accordance with image information.
Is applied to the individual electrodes 8. As a result, electric charges are injected from the electrode 8 into the ink In, and an electric field curtain is formed between and around the electrodes 7, 8. The electric field curtain refers to a temporally and spatially unequal electric field formed around the electrodes and between the electrodes when an alternating voltage is applied between the pair of electrodes. The charged material undergoes a Clone repulsion, that is, an electric field curtain force. The details are described in JP-A-62-111754.

That is, the ink In located between the electrodes 7 and 8 is:
The injected electric charge triggers the electric field curtain force (clone repulsion), and the ink In located near the orifice 6 moves in the direction of arrow a, and has a size corresponding to the electric field curtain force and the amount of electric charge injected from the electrode 8. Ink drop In ′ is ejected into the air.
It flies and is recorded on the recording paper 24.

As described above, the expansion of the bubble 23 is synchronized with the application of the alternating voltage to the electrodes 7 and 8, and the ink In near the nozzle opening is in a state of being pressed by the bubble 23 in the opening direction. Even if a slight voltage is applied to the electrode 8, an amount of ink corresponding to the voltage value is ejected and flies. At the same time as the contraction of the bubble 23, the ink In receives a force in the direction opposite to the orifice 6, so that the ink droplet In 'can be cleaned well.

After the ink droplet In ′ for one dot flies, the ink In is replenished to the orifice 6 from the rear.

After the ink droplet In 'flies, the individual electrode 8 is grounded, and the residual charge in the ink In is erased. However, the ink In
Is not essential, if is charged only by induced charging or internal polarization.

In addition, in the case of injecting electric charge into the ink, it is preferable to apply a negative voltage to the individual electrode 8 because electric charge of negative polarity generally has higher mobility. Of course, a positive voltage is applied to the ink whose physical property is adjusted to make the positive polarity easier to move.

B. Second Embodiment (see FIGS. 4 and 5) In the printer head 30 of the present embodiment, a nozzle 33 is formed between the upper panel 31 and the lower panel 32, similarly to the printer head 1 of the first embodiment. The individual electrodes 35 and 36 are arranged in the vicinity of the orifice 34 of the panels 31 and 32 so as to face each other.
The portion exposed to 3 is covered with an insulating protective film 37. Further, the lower panel 3 is provided with a heating resistor 38 on the opposite side of the individual electrode 36 from the orifice 34. Further, the outer surfaces of the upper panel 2 and the lower panel 3 are doubly covered with an insulating protective film 39 and an ink-phobic insulating protective film 40, and the outer surface (surface layer portion).
The insulating protective film 40 extends to the tip of the nozzle 33.

The same ink as in the first embodiment is used as the ink In.

In the above-described printer head 30, the power supply 42 is turned on / off based on a signal from the control device 41, and a voltage is periodically applied to the heating resistor 38. The heating resistor 38 periodically generates heat in response to turning on and off of the power supply 42, and bubbles 44 generated in the ink In contacting the heating resistor 38 expand and contract. Also,
The ink In vibrates according to the expansion and contraction of the bubble 44.

In this state, when the alternating voltage is applied from the power supply 43 to the electrode 35 of the upper panel 31 and a signal corresponding to the image information is applied from the control device 41 to inject the electric charge into the ink In, the electrodes 35 and 36
An electric field curtain is formed between the ink and the ink In that periodically oscillates based on the expansion and contraction of the bubbles 44. The ink located between the electrodes 35 and 36 and the orifice 34 is strongly urged toward the orifice side. The ink droplets are ejected and fly into the air as ink droplets In ′, and are recorded on the recording paper 45.

C. Third Embodiment (see FIG. 6) The printer head 50 of this embodiment also has a plurality of nozzles 53 arranged in parallel between the upper panel 51 and the lower panel 52, similarly to the printer heads 1 and 30 described above. In each nozzle 53, an individual electrode 55 and piezo oscillators 57, 57 are provided on an upper panel 51, and a lower panel 52
Is provided with a charge injection electrode 56 and piezo oscillators 58, 58, and the electrodes 55 and 56 and the piezo oscillators 57 and 58 are opposed to each other. Except for the charge injection electrode 56, the exposed surfaces of the electrode 55 and the piezo oscillators 57 and 58 exposed to the nozzle 53 are covered with an ink-philic insulating protective film 59 so as not to come into direct contact with the ink In. It is. The outside of the orifice 54 is protected by an insulating coating 60 having ink-phobic properties.

In the printer head 50 having the above configuration, an alternating voltage is applied to the piezo oscillators 57 and 58 from an alternating power supply (not shown), and the piezo oscillators 57 and 58 are distorted in accordance with the frequency of the alternating power. This distortion becomes vibration and the ink In
And the ink In vibrates.

In this state, when an alternating voltage is applied to the individual electrode 55 and a voltage is applied to the charge injection electrode 56 according to image information, the ink
While electric charges are injected into In, an electric field curtain is formed between the electrodes 55 and 56, and the ink In located between the electrodes 55 and 56 and the orifice 54 is ejected into the air as ink droplets.
To fly. Here, as described above, since the ink In is vibrated by the piezoelectric vibrators 57 and 58, the ink In is discharged also in response to a slight voltage signal applied to the electrode 56. Further, the size of the flying ink droplet may be made different by changing the value of the voltage applied to the electrode 56 or the application time according to the image information.
Just by turning off, the control may be performed by controlling the voltage value of the alternating signal input to the piezo elements 57 and 58.

D. Fourth Embodiment (See FIG. 7) In the printer head 60 of the present embodiment, an individual electrode 65 for flying ink is attached to the lower surface of the upper panel 61 near the orifice 64, and the electrode 65 is connected to a switch 66. Through the police box
Connected to 67. An individual electrode 68 is embedded in the lower panel 62 so as to face the electrode 65, and the electrode 68 is grounded. Further, piezo oscillators 70 and 72 are attached to the rear portions of the electrodes 65 and 68 of the panels 61 and 62 so as to face each other. The piezo oscillator 70 is connected to a power source 71, and the other piezo oscillators 71 are connected to a power source 73.
It is connected to the.

In the printer head 60 having the above configuration, an alternating voltage is applied to the piezoelectric vibrator 70 from the power supply 71, and the piezoelectric vibrator 70
Vibration is propagated in the ink In according to the distortion of 70.

On the other hand, the switch 66 is turned on and off in accordance with the presence or absence of image information output from the control device, injecting electric charge into the ink, and forming an electric field curtain therebetween. In addition, the power supply 73 is driven according to the image information from the control device,
A voltage is applied to the piezo vibrator 72. As a result, the ink
Vibration is further applied to In, and an ink droplet having a diameter corresponding to the size is ejected and flies into the air via the orifice 64, and is recorded on a recording paper (not shown).

E. Fifth Embodiment (see FIGS. 8 and 9) In the printer head 80 of the present embodiment, an individual electrode 85 for flying ink is attached near the orifice 84 of the upper panel 81 for each nozzle 83. On the lower panel 82, an individual electrode 86 for charge injection is attached corresponding to the individual electrode 85. In the lower panel 82, a cantilever section 80 is provided on the opposite side of the individual electrode 86 from the orifice 84.
An electrode 92 faces 90.

The section 90 is made of an electret material.
The upper surface of 90 (the surface facing upper panel 81) is charged to the negative electrode, and the lower surface is charged to the positive electrode.

The outer surfaces of the panels 81 and 82 are doubly protected by an insulating protective film 87 and an ink-phobic insulating protective film 88.
The electrode 85 is protected by an insulating protective film 89.

In the printer head 80 having the above configuration, the alternating power supply 93
When the alternating voltage is applied to the electrode 92, the section 90 vibrates, and the vibration propagates to the ink In in the nozzle 83. When an alternating voltage is applied to the individual electrodes 85 from the alternating power supply 91 and a signal corresponding to image information is applied to the charge injection electrode 86 from the control device 94, charges are injected into the ink In, and An electric field curtain is formed between the electrodes 85 and 86, and the ink I located between the electrodes 85 and 86 and the orifice 89 is formed.
n is an ink droplet In ', which flies into the air via the orifice 84, and is recorded on the recording medium 95. Since the ink In receives the vibration of the section 90, even if a slight electric field curtain is generated, the ink In easily ejects and flies as an ink droplet In '.

F. Sixth Embodiment (See FIG. 10) In the printer head 100 of this embodiment, a nozzle 103 formed between panels 101 and 102 made of an insulating material is provided with a rotor 105 facing an orifice 104. Is provided. Rotor
Numeral 105 is made of stainless steel, and the outer peripheral portion is provided with a hydrophilic pattern which is continuous in the axial direction or arranged at regular intervals in the circumferential direction, and the other area is a hydrophobic surface.

The panels 101 and 102 are provided with electrodes 106, 107, 108 and 109, respectively. The electrodes 106 and 107 are grounded, and the electrodes 108 and 109 are connected to alternating power supplies 112 and 113 via switches 110 and 111, respectively. The outputs of the power supplies 112 and 113 are out of phase by 90 °.

The nozzle 103 is provided with a diaphragm pump 120.
Diaphragm pump 120 has electrodes 12 on both sides of piezo element 121.
Attach 2,123, ground electrode 122 in contact with ink In,
The opposite electrode 123 is connected to an alternating power supply 124. The connection surface of the electrode 122 with the ink In is covered with an insulating protective film (not shown).

In the printer head 100 having the above-described configuration, when an alternating voltage is applied to the electrode 123 from the power supply 124, the piezo element 121 vibrates, and the vibration propagates through the ink In.

Further, the rotor 105 rotates in the direction of the arrow, and the ink In is conveyed to the portion facing the orifice 104 in a state of being converted into a line or a dot with the movement of the hydrophilic pattern.

In this state, the control device switches based on the image information.
When the alternating voltage is applied to the electrodes 108 and 109 by opening and closing the electrodes 110 and 111, a traveling wave electric field curtain that progresses toward the orifice 104 is formed between the electrodes 108 and 109 and the electrodes 106 and 107, and the orifice 104 and the rotor 105 rotate according to the rotation of the rotor 105. The ink In conveyed to the opposite portion is ejected and flies from the orifice 104 into the air as an ink droplet, and is recorded on a recording medium (not shown). In addition, since the ink In is in a state where the vibration is propagated from the diaphragm pump 121 and is easily ejected, the amount of the ink In corresponding to the opening / closing time of the switches 110 and 111 flies.

G. Seventh Embodiment (See FIG. 11) In the printer head 130 of the present embodiment, an orifice 132 is provided on the upper panel 131. The lower panel 133 is provided with a pair of piezoelectric elements 135 and 136 facing the orifice 132. An electrode 137 is attached to the opposing surfaces of the piezoelectric elements 135 and 136 and the upper surface of the lower panel 133 located therebetween, and the electrode 137 is connected to a DC power supply 140. Piezoelectric element 135,
Electrodes 138 and 139 are provided on the outer surface of 136.
138 and 139 are alternate power supplies 14 via switches 141 and 143, respectively.
Connected to 2,144. The alternating power supplies 142 and 144 have
180 ゜ wrong. Piezoelectric elements 135 and 13 facing nozzle 134
6. The electrodes 137, 138, and 139 are covered with an insulating protective film 145, except for the part directly attached to the lower panel 133 of the electrode 137.

In the printer head 130 having the above configuration, the DC power supply 1
A voltage is applied to the electrode 137 by 40, and charges are injected into the ink In. Further, the switches 141 and 143 are simultaneously opened and closed according to the image information from the control device. When the switches 141 and 143 are turned on, alternating voltages are applied from the power supplies 142 and 144 to the electrodes 138 and 139, respectively, and the piezoelectric elements 135 and 136 vibrate, and the vibration is generated during the ink In. Propagated ink located at the orifice facing part
In receives a periodic force (up) toward orifice 132. At the same time, an electric field curtain is formed between and around the electrode 137 and the electrodes 138 and 139, and the ink at the orifice facing portion is ejected and flies from the orifice 132 as an ink droplet. The size of the ink droplet corresponds to the on-time of the switches 141 and 143, and a gradation can be obtained by adjusting the time.

H. Print control circuit (see Fig. 12) The circuit configuration of the print control device will be described.

Pixel-divided image recording information input from a host computer, an image reader, a video camera, a still video camera, or the like is first processed by the nozzle control circuit 200 and output as a digital signal having a gradation for each pixel, The signal is converted into an analog signal by the D / A converter 201. This analog signal is sequentially transferred to the analog shift register 202 in synchronization with the shift clock [SC], and the analog image signal for one line is transferred to the analog shift register 20.
Held at 2. The analog image signal for one line in the analog shift register 202 is output in pixel units, input to the converter 203, and converted into pulse data corresponding to the voltage value by the converter 203. And each separate AND gate 204
By line signal from the nozzle control circuit 200 [LC] is recorded in the "H" level of one line with respect to, DC power supply 207 and a plurality of individual electrodes B _1, ~, interposed between the B _n Each separate analog switch 205 and amplifier 206 are driven according to the pulse data from the converter 203, and the corresponding individual electrode
A DC voltage corresponding to the voltage of each pulse data is applied to B ₁ ,..., B _n (see FIG. 13).

J. Manufacture of Panel Manufacturing of a panel having a plurality of nozzle slits will be described with reference to FIGS.

(I) First method (see FIG. 14) a. A chromium film 151 is screen-printed on a glass plate 150 by sputtering, a photosensitive film (photoresist) 152 is applied thereon, and after drying, A predetermined mask pattern 153 is overlapped and irradiated with ultraviolet rays 154. Thereby, the chromium film 151 and the photoresist 152 corresponding to the opening of the mask pattern 153 are removed, and the chromium film 151a and the photoresist 152 corresponding to the shielding portion of the mask pattern 153 remain on the glass plate 150. .

b. Next, the photoresist 152 remaining on the chromium film 151a is removed by a chemical treatment such as etching and washed.

c. Subsequently, a photoresist 155 is applied on the glass plate 150 so as to have a predetermined layer thickness, and the chromium film 151a is irradiated with ultraviolet rays through the mask pattern 153 to expose the chromium film 151a. Photoresist walls 155a are formed on both sides of the chromium film 151a.

d. Finally, the photoresist wall 155 remaining on the glass 150
a is heat cured.

(Ii) Second method (see FIG. 15) a. A photoresist 161 is applied on the silicon plate 160 and dried.

b. Next, a mask pattern (see FIG. 14 (a)) is superposed and irradiated with ultraviolet rays to form grooves 162 in the photoresist 161 and the silicon plate 160, and the surface layer of the silicon 160 is thermally oxidized by silicon etching. Thus, an insulating layer 163 is formed.

c. Subsequently, a chromium layer 164 is formed on the surface of the groove 162 and the photoresist 161 by sputtering.

d. Finally, the photoresist 161 and the chromium film on the surface thereof are removed with a photoresist stripper and a chromium etchant, and then the photoresist 161 is washed.

(Iii) Third method (see FIG. 16) a. A photoresist 171 is applied to the surface of the machineable ceramic plate 170 and dried.

b. Next, a groove 172 is formed by a dicing saw (not shown).

c. Subsequently, a chromium layer 173 is formed on the surface of the groove 172 and the photoresist 171 by sputtering.

d. Finally, the photoresist 171 and the chromium film on the surface thereof are removed with a photoresist stripper and a chromium etchant, and then the substrate is washed.

(Iv) Fourth method (see FIG. 17) a. A groove 181 is formed on the surface of the machineable ceramic plate 180 by a dicing saw (not shown).

b. Next, using the machineable ceramic plate 180 in which the groove 181 is formed as a mold, a liquid crystal polymer 182 is applied to the surface on which the groove 181 is formed, and is dried and cured.

c. Subsequently, the cured liquid crystal polymer plate 182 is removed from the ceramic plate 180, and an electrode 184 is formed in the groove 183 of the polymer plate 182 by an aluminum ion plating method. At this time, the convex portions of the polymer plate are masked.

(V) Others The dimensions of each part of the panel manufactured as described above are as follows:
For example, the wall pitch is 60 μm, the groove width is 30 μm, the groove depth is 30 μm, and the groove length is 5 mm.

K. Materials Used (i) Panels The insulating upper and lower panels that make up each printer head are made of saturated polyester resin, polyamide resin, acrylic resin, ethylene-vinyl acetate copolymer, ion-crosslinked olefin copolymer ( Thermoplastic resins such as ionomers), styrene-butadiene block copolymers, polycarbonates, vinyl chloride-vinyl acetate copolymers, cellulose esters, polyimides; photocurable resins; poly-N-vinylcarbazole, polyvinylpyrene, polyvinylanthracene, etc. And a liquid crystal polymer; a resin comprising a mixture with a liquid crystal polymer, or a mixture of these as appropriate.

In addition, the resin is 1.0 × 10 ¹³ Ω when measured alone.
-It is desirable to have a volume resistance of not less than cm. In addition to the above resins, silica-based glasses; ceramics such as mammable ceramics; ferrite materials and the like can also be used. Further, additives such as glass fiber and tismo (potassium titanate, polytetrafluoroethylene) (F-based resin) may be added to the resin at a ratio of about 10 to 60 wt%.

Here, toughness, dimensional accuracy and hydrophilicity are improved by adding glass fiber and Tismo, and water repellency is improved by adding polytetrafluoroethylene.

(Ii) Insulating protective film for electrode protection The insulating protective film for protecting electrodes and panels in contact with the ink is made of insulating ceramics such as S ₁ O ₂ , Al ₂ O ₃ , a-S
glass made of i-O _2, etc., organic, enamel, polyimide resins, epoxy resins, acrylic resins, polyethylene resins, the insulating material such as polyester resin, vacuum deposition, sputtering, coating, formed in a thin layer by the dip and the like.

In the first and second embodiments and the like, a material mainly containing a large amount of an element having a small surface energy (for example, fluorine) is used as the ink-phobic insulating protective film that covers the outside of the panel. If this ink-phobic insulating protective film is used, the ink which is about to spill out of the orifice is repelled and prevented from falling, so that the ink does not fall on the recording medium and noise is not generated in the image. In addition, the ink to be ejected and flying is improved, and fine ink droplets generated between the ejected ink droplets and the ink in the orifice do not scatter on the recording medium. A beautiful image can be obtained without noise.

Incidentally, an insulating film for protecting the ink contact surface of the electrode is not always necessary, but depends on the resistance value of the ink. That is, when the resistance value of the ink is ρ <10 ⁵ Ω · cm, an insulating film is provided to prevent a short circuit between the individual electrodes. However, when the resistance value of the ink is ρ> 10 ⁵ Ω · cm, the insulating film is unnecessary.

(Iii) Alternating power supply for generating electric field curtain The alternating power supply for generating electric field curtain is, for example, frequency: 3KH
z, a device that outputs a peak-to-peak voltage (Vp-p): 200 V is used. The alternating waveform may be a rectangular wave, a triangular wave, or a sawtooth wave. Further, the alternating power source may be a three-phase alternating current, or a plurality of single-phase alternating currents, and these phases may be different from each other. In other words, an electric field curtain from the rear of the nozzle toward the orifice can be formed. I just need.

(Iv) The heating resistor used in the first and second embodiments the heating resistor, for example, silicon-containing compounds such as _{ZrB 2, Ta 2 N, W} , Ni-Cr, Sn
It is composed of O ₂ or Pd—Ag as a main component, Ru as a main component, a Si diffusion resistor, a semiconductor PN junction, or the like. This heating resistor is provided on the panel by sputtering, vapor deposition, or the like.

(V) Ink As the ink, for example, inks 1 to 5 in the following table are used.

Ink 5 In the case of the recording apparatus using the printer heads of Embodiments 1 and 2, instead of the direct black inks 2 to 4, a heat-generating ink in which the powder (0.01 to 0.5 μm) of the heating resistor is dispersed is used. You may.

The general properties of the ink used in the recording apparatus will be described.

The ink agent includes a case where a pigment (inking pigment, an inking material) dispersed in a liquid moves using the liquid as a carrier and a case where a coloring material is dispersed or dissolved in the liquid. There are two cases where the entire liquid behaves as an inking material without moving through the liquid. The former is a two-component system because a carrier liquid is used for pigment charging and pigment transfer, and the latter is regarded as a one-component system because ink transfer is performed without using a carrier liquid.

The inks 1 to 5 are one-component inks in which a dye is dissolved in an aqueous solvent. In addition, the inks 1 to 5 were water-soluble inks having a volume resistivity of 10 ^{7 to 8} Ω · cm or less.
An organic one-component ink having a volume resistivity of 10 ^{7 to 8} Ω · cm or more may be used.

One-component inks have features that are not found in two-component inks, such as ease of handling and stability.

Generally, a pigment is not soluble in water unless it has an aqueous group after a surface treatment, so that a high-resistance ink is used in actual use.

Hereinafter, the charging of the liquid ink and the pigment in the high-resistance ink will be described.

There are many unclear points about the mechanism of the generation of charge in the pigment dispersed in the liquid, similar to the triboelectric charging of powder toner for electrophotography, but it is thought that the polarity of the pigment is controlled by the following mechanism. Can be

Oil-soluble metallic soap dissociates and adsorbs on pigment particles to give a positive charge.

 2MX + TMX → [TMMX] + X MX Here, TMX converts the undissociated metal soap molecule MX in the liquid.
Adsorbed pigment particles, [TMMX] Is the dissociated ion M Suck
Pigment particles charged and charged, X MX has a micelle structure
Is a counter ion. Weak polarity like carbon black
Pigment can be dissolved by adding resin.
The separation is promoted, and the charge is strongly stabilized.

Hydrogen ions on the surface of the acidic particles are desorbed by the oil-soluble base, and the particles are charged with polarity.

 TH + RBT + RBH  Here, TH is a particle having an acidic group, and RB is an oil-soluble salt.
Group, T Is negatively charged toner particles, RBH Is a positively charged ion
With carbon black surface and adsorbed resin
Acid-soluble salts such as amines
The group becomes charged depending on the group. This is also
Addition of metal soap causes re-adsorption.
Causes the charge to reverse. Thus, the pigment surface and its
Controls desorption of dissociated ions etc. of substances adsorbed on the surface
Behaved differently.

The properties required of the carrier liquid in the high-resistance ink of the present invention are as follows: ^B. Have an electrical resistance of 10 ⁷ to ⁸ Ω · cm or more to prevent electric charge leakage; (B) chemically inert so as not to damage the ink grooves, orifice members, and electrode materials; From the viewpoint of toxicity, flammability, and no odor, an isoparaffinic solvent having a boiling point of 120 to 200 ° C is used.

The developer is obtained by dispersing pigment particles (fine particles obtained by adsorbing a resin component having dispersibility, polarity controllability, fixability, and the like to a pigment such as carbon black) in a colloidal form in the carrier liquid. It is.

As the colored body, carbon black or the like is used for the black pigment. There are two types of carbon black, channel black and furnace black, according to the production method. The former is suitable for acidic pigments, and the latter is neutral or basic and suitable for pigments. However, if furnace black is oxidized with nitric acid or the like to increase volatile components and oxygen content, it can be used as a substitute for channel black in pigments.

 Red color: Tan of mixture with indolenine xanthene dye
Molybdic acid bustophosphate lake, cationic azo dye
Mixed lake with xanthene dye Magenta: Acid azo dye metal salt Orange: Azo dye copolymer containing aminotriazoline group Yellow: Azo dye guanidium salt, Yellow azo pigment xante
Or indolenine dyes and molybdotungstic acid
Blue precipitate: guanidinium salt, anthracene phthalocyanine
Mixture Purple: Metal complex of formazan derivative As a secondary pigment, the polymer is strongly adsorbed on the particles
The anchor base needs a certain length in order to
Or a grout copolymer. Therefore, poly
Mer chain A is an anchor to the particle surface and is inert to the dispersion medium
Has a strong affinity on the surface of the polymer, and the polymer chain B is a steric repulsion layer
Dissolves in the dispersion medium and has almost no affinity to the particle surface
Choose -COOH,-present in polymer in non-aqueous system
The OH group becomes a potential determining substance of the dispersed particles, Into particles
give.

As the polymer chain A, such as methyl methacrylate, and as the polymer chain B, laurin methacrylate,
-COOH as a charge group such as 2-hexyne methacrylate and 12-hydroxystearic acid, N (CH ₃ ) ₂ , quaternary ammonium salt and sulfonate are copolymerized.

The following can be considered as a method of controlling the pigment charging property.

A metal salt of an organic acid soluble in the carrier liquid is added by a method using a charge control agent.

For example, naphthenic acid, linoleic acid, oleic acid, octyl acid, Parumishin acid, metal salts of carboxylic acids such as stearic acid, metal salts such as C _{12 to 16} alkyl sulfates, C _{3 to 18} alkyl phosphates. As the metal, lead, manganese, cobalt, calcium, aluminum, zinc, titanium and the like are used.

A carrier liquid having a different dielectric constant is added.

For example, when a liquid that increases the dielectric constant such as butanol or isopropanol is added to the carrier liquid, the polarity of the developer increases, and when a lower aliphatic hydrocarbon is added, the conductivity decreases and the polarity increases. Utilizes the polar groups of the resin adsorbed on the pigment particles.

For example, as described above, -NH ₂ as a polar group of the polymer that adsorbs or grout polymerizing _{pigment, -CONH 2, -CN, -OH,} -N (CH 3) 2, -COO
H, -Cl, a -NO _2, or the like is used.

A pigment with a large charge is added.

 For example, a phthalocyanine containing no metal is added.

Other surfactants are added.

For example, quaternary ammonium or polyethylene glycol having an NH ₂ group is added.

Charge by carrier liquid.

As a dispersion medium for the pigment particles, an isoparaffin-based petroleum agent, glycerin, anone, dioxane, ethylene glycol, silicone oil, or the like is usually used.

〔The invention's effect〕

As apparent from the above description, according to the recording apparatus of the first aspect, the ink of the liquid in the ink chamber is pushed in the orifice direction by the applying means, and the ink is combined with the electric field curtain force by the electric field forming means. Discharges and flies from the orifice. Here, the ink in the vicinity of the orifice is in a dynamic state due to the pushing force of the applying means and is in a state where it is easily ejected from the orifice. Therefore, the ink is ejected even by a slight electric field curtain force. Therefore, the intensity of the alternating electric field for applying the electric field curtain force can be reduced, and the control of the ink flying can be performed with high accuracy.

In the recording apparatus according to the second aspect, at least one of the electric field forming unit and the applying unit is controlled in multiple stages by a control unit according to an image signal, and the ink ejection amount can be controlled. Since the electric field curtain force required for the electric field forming means is small by the action of the means, it is possible to control the ink discharge amount with high accuracy.

Further, in the recording apparatus according to the third aspect, the vicinity of the orifice of the container is subjected to an ink-phobic treatment. Therefore, the ink that is about to spill out of the orifice is prevented from being repelled and falling onto the recording medium. Further, the amount of ink to be ejected is improved, which is advantageous in controlling the ink flight.

[Brief description of the drawings]

FIGS. 1, 2 and 3 show the printer head of the first embodiment.
The figure is a partial sectional view, FIG. 3 is a partial perspective view, and FIGS.
FIG. 6 is a partial cross-sectional view of the printer head of the third embodiment, FIG. 7 is a partial cross-sectional view of the printer head of the fourth embodiment, FIGS. FIG. 10 is a partial sectional view of the printer head of the embodiment, FIG. 10 is a sectional view of the printer head of the sixth embodiment, FIG. 11 is a sectional view of the printer head of the seventh embodiment, FIG. The figures are timing charts showing the output states of signals in the print control circuit, and FIGS.
(C) is a drawing showing the manufacturing process of the panel. 1 ... Printer head, 2 ... Top panel, 3 ... Bottom panel, 5 ... Nozzle, 6 ... Orifice, 7,
8 …… Individual electrode, 9,10 …… Heating resistor, In… Ink, I
n '... Ink drops.

Continuation of front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B41J 2/05 B41J 2/06

Claims (3)

(57) [Claims] 1. A recording apparatus for recording ink by supplying ink to a printing medium, comprising: a container having an ink chamber for accommodating a liquid ink; and an orifice as an ink discharge port from the ink chamber; Electric field forming means for applying an alternating electric field to the ink contained in the container in the vicinity to apply an electric field curtain force to the ink toward the orifice, and applying means for applying a force to push the ink in the ink chamber in the orifice direction, Wherein the ink is ejected from the orifice by the combined force of the pushing force of the applying means and the electric field curtain force of the electric field forming means. 2. A recording apparatus according to claim 1, further comprising control means for controlling at least one of said electric field forming means and said applying means in multiple stages according to an image signal. apparatus. 3. The recording apparatus according to claim 1, wherein a sparse ink treatment is applied to the vicinity of the orifice of the container.