JPS58212959A - Ink recording head - Google Patents

Abstract

PURPOSE:To obtain a printer capable of more effectively performing the discharge of liquid ink by electric osmosis by using an ink recording head having a closed portion with an opening leading to the groove of an opened portion. CONSTITUTION:An ink 4 is supplied through an electrode 3 to a porous material 2 by the spongy material 11' of a container 11. A recording paper 12 is set about 200mum away from the end 1'' of a dielectric base plate 1. When OFF voltage Voff is applied to a recording electrode 5, ink 4 located at the tip 5'' of the recording electrode in a through hole 6a is sucked up by suctional action toward the electrode 3 side through the surface 5' of the recording electrode in the groove 6 and then through an ink-modulating portion 7' and the porous material 2, whereby preventing the adhesion of ink. When negative voltage Von is applied, however, the ink 4 is sent under pressure toward the tip of the through hole 6a, or the tip 5'' side of the recording electrode, through the groove 6 and the surface 5' of the recording electrode in the hole 6a by means of osmotic pressure. The ink 4 thus sent forms the flying 4' of ink by electric osmotic pressures and therefore, spotted inks 18 are adhered onto a recording medium 12.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in an ink recording head that electrically discharges liquid ink to record ink on a recording medium.

The principle of an ink recording head that utilizes electroosmosis of liquid ink has already been proposed by a non-inventor. The principle is that recording electrodes extending to one edge of this support substrate are arranged on the surface of a support substrate that allows liquid ink to electroosmose, and the liquid is supplied offset from this edge. An ink convergence part is formed by installing a porous body that is impregnated with water, a liquid ink permeable electrode is installed on the surface of the porous body on the opposite side to the supporting substrate, and the recording electrode surface and the porous body are An ink modulation section is formed by forming a gap between the surface and the surface through which liquid ink can move. A recording signal voltage is selectively applied between the recording electrode, the liquid ink-permeable electrode, and the recording electrode, and the signal voltage causes the ink to converge through the gap by electroosmosis in the thickness direction of the porous material. The ink is caused to ooze out, the ink is focused by electroosmosis in the surface direction of the support substrate due to the voltage between the recording electrodes, and this ink is contacted and printed on the recording medium.

Although this method exhibits high performance for contact printing, there is still room for further improvement, such as wear of the recording head due to contact with the recording medium, and further instability due to dust adhering to the recording head. ing.

In view of the above problems, the present invention aims to provide an ink recording head that enables non-contact ink recording by flying ink ejection. A closing part having a hole opening through one edge?
: a supporting substrate having recording electrodes disposed in at least the grooves among the grooves and through-holes, and a liquid ink permeable layer on the open portion of the supporting substrate through a porous body; An electrode is installed in such a manner that liquid ink is supplied to the porous body, and a full recording signal voltage is applied between the recording electrode and the liquid ink permeable electrode. By electroosmosis of the liquid ink into the porous body,
The ink recording head electrically controls the amount of liquid ink ejected through the through hole.

! In the above, an auxiliary electrode is placed on one line end side of the support substrate, and a voltage is applied between it and the recording electrode to control the electroosmosis of the liquid ink at least on the surface of the through hole, and further increase the amount of ink discharged. Electrically controlled (wealth) and trying to improve performance.

Hereinafter, all non-inventive aspects will be described in detail with regard to Examples.

FIG. 1 is a perspective partial structural view of an embodiment of an ink recording head according to the invention and an ink recording apparatus using this head.

In the figure, 1 is a plate-shaped dielectric support base made of a plastic plate such as cellulose acetate, polyimide, or phenol resin, a glass plate, or a porcelain plate such as alumina, and 2 is a plastic material such as cellulose acetate or cellulose nitrate. It is made of glass material, porcelain material such as alumina, etc., and has holes with an average pore diameter and an average gap of about 0.1 to 10μ〃z that penetrate continuously in the thickness direction, and a small #l1 gap. The membrane or plate-like porous body 3 with a thickness of about 20 to 20Ql1 is an electrode that allows oil-based or water-based liquid ink 4 supplied from the outside to pass through, and the thickness is, for example, 20 to 200N1.
10 per inch on phosphor bronze or stainless steel plate with m8 degree
A mesh electrode is formed by drilling holes at a density of about 0 to 400 meshes (-jZ, that is, 100 to 400 meshes).

The porous body 2 is lightly pressed against the dielectric substrate surface 1' via the liquid ink permeable electrode 3. 6 is, for example, cr
○, Ni-0r alloy is deposited thinly to about 1 to 0.3 μm, and then Au, etc. is deposited on the soil to a thickness of 1 to 3 μm by vapor deposition or plating.
The recording electrodes were deposited and arranged at a pitch of about 11 m, and the arrangement pitch was P.

This recording electrode 5 has this electrode surface 6' and the porous body surface 2.
In order to form a gap between the surface 1' and the surface 1' of the dielectric substrate 1 by etching, cutting, or molding, a gap with a depth d2, for example, 1
It is deposited in a groove 6 with a width of 0 to 10011 m and a width αP (however, α is 1).

For example, P is 125 to 61.26 μη7 (i.e. 8 μη7
mm-16 mm), /2U approximately 0.2 to 0.8.

The edge 2' of the porous body 2 is the edge 1 of the dielectric substrate 1.
An ink modulating section 7' is formed by installing the ink modulating section 7' on the open section 7 having a length L of about 2 to 10.alpha., which is located 8 degrees inside M=tso~200 .mu.m.

A closing portion 8 is formed in the length M portion, and in some cases, a shielding plate 9, preferably made of the same material as the support substrate 1, is attached to the surface 12L of the support substrate 12L with an adhesive 10', leaving a groove 6. Glue with. Therefore, in this portion, the groove 6 is connected to the open portion 7, and a penetrating hole 6a that opens toward the edge 1' is also formed.

The 10,000 edges of the liquid ink permeable electrode 3 may be in contact with the shielding plate 9, but in order to prevent dielectric breakdown, the edges 2' of the porous body 2 should also have a diagonal of about 5 to 100 μm inside. It can be positioned as follows. On the other edge end side of the porous body 2, the surface 2' of the porous body is sealed with the surface 1' of the dielectric substrate and the coating surface of the recording electrode 6 in the groove 6 using a sealing agent 10, and liquid ink is applied to the surface 2' of the porous body 2'. Prevent the leakage of 4.

The liquid ink 4 to be applied to the ink recording head 100 is supplied from the ink dispenser 11 to the porous body 2 through the electrode 3 and impregnated therein by utilizing the capillarity of the sponge body 11', as illustrated in the figure. The ink recording adhesion 18 is all over the edge 1' of the recording medium 12, such as paper! 112Q.

Place it about lim in front of you.

As shown in the figure, the ink recording head 100 is driven by applying an off-voltage Voff (with an amplitude of l V
off l≧0) and modulated by the ink recording input signal n
A recording signal voltage vs is applied, and these voltages are switched alternately to record one line divided into two parts.

The liquid ink 4 can be prepared by dissolving ionic dyes or direct dyes in an aqueous bath such as water or alcohol, or by dissolving ionic dyes and direct dyes in a medium, or by dissolving ionic dyes and direct dyes in a medium such as water, alcohol, etc. An oil-based ink is formed by dissolving an oil-soluble dye or the like in a non-aqueous solvent, and if necessary, a surfactant is added thereto.

The charge control agent and the vehicle material are completely dissolved to make the porous body 2 electroosmotic.

These inks 4 preferably have a resistivity of 103 Ωm or more, a viscosity of 100p or less, and a surface tension of 15 to 4 od.
A value of about yne/CIn'&47v is set.

From the viewpoint of dielectric strength, it is preferable to use an oil-based ink with a specific resistance of 10 7 Ω or more.

The electroosmotic polarity of the liquid ink 4 is in the negative potential direction.

Any number n in the positive potential direction can be selected materially, but in the figure,
The case where electroosmosis occurs in the direction of negative potential is exemplified.

Amplitude l of recording signal voltage vs Vs l is 0 to 1Vonl
(however, 1Vonl>1Voffl), the polarity of vS is opposite to Voff, and Vs'
D, Superimposed on Voff
It has a value ranging from f to Won.

The off-voltage Voff has a polarity that causes the liquid ink 4 on the recording electrode surface 5' to be sucked up to the liquid ink permeable electrode 3 side through the entire porous body 2, as shown by the arrow 13 in the figure, by electroosmosis in the thickness direction of the porous body 2. In this example, a positive voltage is applied to Voff.

On the other hand, when the recording voltage Vs is applied, the recording electrode surface 5 is transferred from the electrode 3 side through the porous body 2 by electroosmosis in the thickness direction of the porous body 2.
Select n1 as the polarity for osmotic pumping on the ' side as shown by arrow 14 in the figure.
In this example, a negative voltage is applied to vs.

In the figure, off voltage Voff+recording voltage Vs = V
In the part where off is applied, the liquid ink 4 located at the tip 6' of the recording electrode in the through hole 6a is transmitted along the surface 6' of the recording electrode in the groove 6 as indicated by the solid arrow 15 due to the suction action as shown by the arrow 13. Since the ink is sucked up to the electrode 3 side via the ink modulating section 7' and the porous body 2, no ink adhesion 18 can occur on the recording medium 12.

However, when a negative voltage vs-von is applied to the portion of the recording electrode 6 at f', when the voltage amplitude is the same, the osmotic pressure is transferred as shown by the arrow 14 according to the pulse width (contrary to the above). As shown by the solid arrow 16, the groove 6. Recording electrode surface 5' inside hole 6a
The tip of the through hole 6a, that is, the recording electrode 6
'' side.

In this case, if the electroosmotic polarity of the dielectric substrate 1 and therefore the substrate surface 1' with respect to the liquid ink 4 is selected to be the same polarity as that of the porous body 2, that is, in the negative potential direction in exceptional cases, the recording electrode in the ink modulation section 7' In the bonding gap between the substrate surface 1' including the gap surface 1a and the porous body surface 2', a potential difference Vs
The off-voltage Voff of the liquid ink 4 is increased by electroosmosis in the plane direction as shown by arrow 17 in the recording electrode gap surface 1' and porous body surface 2' corresponding to Voff, and by electroosmosis in the thickness direction as shown by arrow 14 corresponding to vs-von. Diffusion 19 of the applied voltage to the recording electrode side can be prevented.

Therefore, the osmotic ink as indicated by the arrow 16 corresponding to vs-vOn is effectively pumped around the groove 6 toward the recording electrode tip 5' side, that is, to (III) of the through hole 6.

This force-fed liquid ink causes ink flying 4' due to its electroosmotic pressure, resulting in dotted ink adhesion 18 on the recording medium 121m.

Therefore, the off-voltage Vof is applied to the odd-numbered and even-numbered recording electrodes 5.
A recording voltage Vsffi corresponding to f is applied alternately, and this Af
Fi is switched alternately, and recording medium 1 is switched in synchronization with this.
0 Feed the paper in a pulse like the arrow 20! ll, patterns, characters, or images can be recorded in so-called bipartite line sequential fashion, in which the - line is divided into knee I. In general, the electroosmotic degree U of the liquid ink 4 is as follows if the material is selected appropriately. 166 to 1σ' CI//V-cs.

Electric field strength E1id in the thickness direction of the porous membrane 2 related to Voff and vS, oil-based ink 4 having an electric field strength E1id of 10'Ω (1) or more
For example, it can be selected to be about 2 x 10' V/11n.

P=10 on, a=o, E5, d=2X10 t
jl, L = 2G, each electroosmotic degree is 1σ6
~1σ4C7J/vSec, assuming that there is no diffusion 19 due to ink pressure feeding as shown by arrow 14.16, and the moving length of liquid ink 4 at the recording electrode tip 6' 1=1o-2a
If we approximate the time τ1 required to obtain nf by omitting the hydrodynamic viscous resistance effect, we can see that the movement of the liquid ink 4 in the porous body 2 and the grooves 6 of the ink modulating section 7' The speed is converted to LrLG-L/d=10' times within n,
T, :=5X1σ6~5X10""5Tffi, the speed of ink flying 4' 1) = (1/r1u2x10
' to 2X1 octn/sty: It can be seen that the ink ejection flight 4' can occur at a sufficiently high speed.

In addition, if U is sufficiently large and the ink cannot be spread and dispersed 19 without failure, the porous body surface 2' and the substrate surface 1' are bonded with adhesive, leaving the grooves 6 in the ink modulating section 7'. Can be sealed.

The maximum value of the amplitude of Won is the electric field strength E1 as in the above example.
It is preferable to select Voff to be about 2 x 10' V/l:m. However, if Voff is too large, too much ink 4 may be sucked in, so the Van J : !: It is also desirable to choose l to be small.

Incidentally, to record a halftone image, the signal voltage vs is amplitude modulated and pulse width modulated to change the density of the ink recording 18.

In this case, when the amplitude and pulse width of von are small,
A high voltage v) Ik with the same polarity as on and a large amplitude of Won, and a counter electrode 21 on the back side of the recording medium 12.
7J11, the ink flying 4 is caused by the Coulomb force based on the potential difference VIIVOn between the electrode tip 6' and
′ has the opposite polarity to VOTI, which has the advantage that it can be effectively assisted with a lower voltage.

Note that the cross-sectional area of the through hole θ
If the cross section is chosen to be smaller than the cross section of the ink, the ink will fly more effectively. In addition, although it is easy to manufacture by adhering a shielding plate 9 to the through hole 6a, it is possible to form a shield plate 9 of "-2" size integrally with the support substrate 1, and make a circular hole etc. there. 6. FIG. 2 is a perspective partial structural view of another embodiment of the ink recording head according to the invention, showing a power supply system.

In this embodiment, in the ink modulating section 7', the porous body surface 2' and the adhesive 1 are formed on the support substrate surface 1', excluding the groove 6 and the metal.
Since there is no ink diffusion 19 as shown in FIG.
s is applied.

The surfaces 6b and 6b' of the through hole 61L of the closure part 8 are electroosmotic to the liquid ink 4 and are located inside the edge 1' at the tip 5'' of the recording electrode n1. Auxiliary electrodes 221L, 22b, such as vapor-deposited films of gold or the like, which are independent of each other, are deposited on the edge surfaces 1b, gb in contact with the through-hole 6a.

In an exceptional case, the recording signal voltage vs is such that, for multiplex operation, the recording electrodes 5 are grouped into groups of three and connected in parallel. Auxiliary electrodes also correspond to this group,
The recording electrode 6 is divided into three units, 22 &, 22 b.

The dimensions of the surface 9 of the groove 6 and the surfaces 6b and 6b' of the through hole 6 are as follows.
The liquid ink having the same polarity as the porous membrane 2 is configured to be electroosmotic therein. This can be realized, for example, when the porous membrane 2 is made of cellulose acetate, and the supporting substrate 1 and the shielding plate 9 are also made of cellulose acetate. In Figure 2,
As in FIG. 1, a case is illustrated in which the ink 4 electroosmoses in the negative potential direction.

Thus, by the same principle as explained in FIG. 1, Vs-V
In the part where off recording voltage is applied, arrow 1
Ink ejection 4' does not occur due to ink suction as shown in 6. vs-vOn is applied t''L friend valve part,'arrow 16
Ink is pumped as shown in FIG. 2. However, if the switch S1' is turned to the Ia terminal, a negative voltage Vn' having the same polarity as vOn is applied, and the amplitude of vn is greater than 'l:Won', the auxiliary electrode 2
Since a negative potential is formed with respect to the tip 5'' of the recording electrode 2aU, the ink movement 16 is accelerated by electroosmosis as indicated by the arrow 16L at the through-hole surfaces 61) and 6b', allowing more efficient ink ejection 4'. .

-Even if vs-von is applied, the auxiliary electrode 22 is turned to the terminal 'Ib side of switch S2 and a positive voltage vP is applied.
In part b, since the electrode tip 5' forms a negative potential with respect to the electrode 22, the direction of electroosmosis is reversed as shown by the arrow 16b, blocking the ink ejection 4' and causing the ink recording 18 on the recording medium 12. Does not occur. In this reversal as shown by arrow 16b, vn
This occurs even when the amplitude of VOn is a negative voltage smaller than VOn or is zero, and the speed of the ink ejection 11f 4' is reduced.
Furthermore, it is also possible to prevent it.

Thus, in a multiplex operation in which groups of recording electrodes 5 are connected in parallel, the switches S1, S2, etc. are activated in synchronization with the application of the recording voltage vs corresponding to each group.
- Ink recording can be performed in this group by switching all and applying Vne. shift by 1, the amplitude of vn is W
Since ink ejection 4' is blocked in a portion where vP is applied less than on or where vP is applied, time-division so-called multi-blend printing can be performed.

In this embodiment, the recording electrodes 6 were grouped into groups of three, so-called odd numbers were used as a group, but as shown in FIG.
In bipartite line sequential driving that requires application of off-voltage Voff to adjacent recording electrodes 6, it is preferable to group even numbered electrodes. Through-hole surface 6b,
The electrical □ osmotic polarity of 6b' can be chosen in the opposite direction, ie in the direction of positive potential.

In this case, if Kane's law is used, the support substrate 1. The material of the shielding plate 9 is, for example, lead titanate or PLZT, and the dielectric constant is liquid ink 4 (usually oil-based ink is 88.-3).
~10) All you have to do is use a ferroelectric porcelain plate or the like. At this time, contrary to the above explanation, the electroosmosis 16a
corresponds to vP, and the electroosmosis 16b corresponds to vn. In this case, even if vn and vP are zero V, the recording electrode tip 5' with vOn applied to the auxiliary electrodes 22&, 22b, etc. Electroosmosis 16 because it forms a positive potential against
Electroosmosis 16b occurs when the electrode tip 5' is at a positive potential in response to the application of Ji and Voff, and there is a relationship that always promotes ink movement 16.16 due to vOn+Voff, which is a preferable configuration.

Note that as in the configuration shown in FIG. 1, the full length of the ink jet 4' can be increased by high voltage vH,
When the electroosmotic polarity of b and 6b' is in the direction of negative potential, the negative voltage is set as described above, and when it is in the direction of positive potential, it is set as positive voltage, and how many nx of the amplitude kVn+Vp? It's fine if the voltage is just as high.

The above description focuses on multiplex operation (2), but in normal parallel operation or bipartite line sequential operation, division of the auxiliary electrodes is not necessary.

In this case, it is preferable to apply vn+v to a single auxiliary electrode and use it for fine adjustment of recording characteristics independently of vs. It is desirable that the electric field strength related to vn and vP between the auxiliary electrode such as 22J 22b and the electrode tip 5'' be selected within 2X10'V/Crn, taking into account all dielectric breakdown.Electrodes 221L, 22b and the electrode tip 5'/ The electrode gap between the two electrodes is selected to be, for example, about 50 lt m to 60 ol 1 m.

In FIG. 2, the electrode tip 5m extends to the through hole 6a, but it may also be located in the open portion 7 (that is, the ink modulation portion 7') within the range of the electrode gap. The cut auxiliary electrodes 221L, 22b are not limited to the edge portion 1b, but may be installed by partially penetrating into the through hole 6a and extending to the surfaces 6b, 6b'.

As described above, when the electrode tip 5'' is in the opening 7, the recording electrode 5 is attached to the surface of the groove 6, the surface 6b,
It has an electroosmotic property of the same polarity as 6b', preferably 1. Note that the substrate 1. In addition to the constituent material of the shielding plate 9, a material that imparts electroosmotic property may be attached to its surface.

Thus, among the surfaces 6b and 6b' of the groove 6 and the through hole 6a,
If at least the surfaces 6b, 6b' (i.e., the i-ink 4) are made electroosmotic, the recording operation can be controlled.

The above configuration can be applied to FIGS. 1 and 2 as appropriate.

As described above, the invention is an ink recording head having a closed part that connects with a groove of an open part to accommodate a hole that penetrates and opens, and which effectively discharges liquid ink by electroosmosis. In addition, it is possible to electrically control the t'L, which has great industrial effects.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a perspective view of an ink recording head according to one embodiment of the invention and an ink recording apparatus as an application thereof, and FIG. 2 is a perspective partial structure of an ink recording head according to another embodiment of the invention. and a diagram showing a power feeding method. 1...Supporting substrate, 2...Porous body, 3
...Liquid ink permeable electrode, 4...Liquid ink, 4'...Liquid ink discharge, 6...
...Recording electrode, 6...Groove, 6a...
Through hole, 7... Opening part, 8... Closing part, 9... Shielding plate, 12... Recording medium,
18... Recording adhesion ink, 222L, 22b.
...Auxiliary electrode.

Claims (2)

[Claims] (1) It has an open part having a groove, and a closed part having a hole connected to the groove and penetrating and opening toward one edge, and recording is made in at least the groove among the groove and the through hole. The electrodes are arranged
A supporting substrate is provided, and an electrode permeable to liquid ink is installed on the open portion of the supporting substrate through a porous body, and the liquid ink is supplied to the porous body.
A recording signal voltage is applied between the recording electrode and the liquid ink permeable electrode, and electroosmosis of the liquid ink into the porous body in relation to this signal voltage causes the liquid ink to flow through the through hole. An ink recording head characterized in that the ejection pattern of the ink is electrically controlled. (2) Among the surfaces of the groove and the through hole, at least the surface of the through hole is configured to allow the liquid ink to electro-osmote, and the surface of one edge of the support substrate is continuously connected to the surface of the through hole. All auxiliary electrodes that enter the through hole are installed, and a full voltage is applied between the auxiliary electrode and the recording electrode, so that electricity of the liquid ink flows through the surface of the through hole located between these electrodes. Claim 1 characterized in that the liquid ink is further electrically controlled by the penetration rate and the ejection of the liquid ink.
The ink recording head described in section.