JPH0313068B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in electroosmotic ink recording devices.

Several proposals have been made by one of the inventors of the present invention regarding the above-mentioned ink recording apparatus. The principle is that a plurality of first electrodes are arranged, a fixed dielectric material having a two-dimensional spread, a second electrode,
means for supplying liquid ink to the dielectric, and selectively applies a signal voltage to the dielectric and the liquid ink via the first electrode and the second electrode, and corresponds to the signal voltage. At least electroosmosis the liquid ink into the dielectric, selectively forming and modulating a controlled liquid ink portion on the first electrode, particularly on the co-end side of one of the electrodes, and applying the liquid ink to the dielectric. This is an electroosmotic ink recording device that attaches to and records on a recording medium such as paper.

To give an example of the configuration of a typical ink recording head, the first configuration has linear first electrodes penetrating through a solid dielectric substrate at an arrangement interval corresponding to the recording density.
A second electrode consisting of a plurality of conductive parts facing each other with the arranged first electrode group as the center,
Electroosmosis of liquid ink on the surface of the dielectric substrate, which is placed on the surface of the dielectric substrate and located between the first electrode and the second electrode, is used.

In the second configuration, the first electrode is inserted between two non-porous dielectric substrates so that one end of the first electrode is exposed, and the outer surface of these dielectric substrates is exposed. A second electrode is disposed at the end of the first electrode, and electroosmosis of the liquid ink at the side edge surfaces of the dielectric substrates located between the second electrode and the end of the first electrode is utilized.

In the third configuration, in the second configuration described above, the two dielectric base materials are formed of a porous material having pores that substantially penetrate in the thickness direction, and the second electrode is made permeable to liquid ink. The electroosmotic property of the liquid ink in the thickness direction of the porous body is utilized together with the above-mentioned side edge end faces. The liquid ink moves together with the above-mentioned side edge end surface through the porous body insertion gap where the first electrode is located. In the fourth configuration, a first electrode is disposed on one surface of a first non-porous dielectric base material so that one end thereof extends to the edge of the first dielectric base material, and this electrode arrangement is performed. A second non-porous dielectric base material is disposed on the design surface slightly shifted inward from the edge of the first dielectric base material, so that one end side of the first electrode is
An exposed edge surface is formed which is exposed together with the edge surface of the first dielectric substrate, and a second dielectric substrate is formed on the surface of the second dielectric substrate opposite to the surface on which the first electrode is disposed.
An electrode is installed, and electroosmosis of the liquid ink is utilized on the side edge surface of the second dielectric substrate located between the second electrode and the exposed edge surface, and on the exposed edge surface.

A fifth configuration is a second configuration in the fourth configuration described above.
The dielectric base material is formed of a porous material having pores substantially penetrating through the thickness direction, and the second electrode is configured to be permeable to liquid ink.

Compared to the fourth configuration, the liquid ink undergoes electroosmosis in the thickness direction of the porous body, and the liquid ink penetrates through the bonding gap between the first electrode installation surface and the porous body surface. Movement is added.

In addition, there are various other configurations based on the principle mentioned above, but in any case, at least one of the liquid conditions on the side edge surface of the dielectric base material, the thickness direction of the dielectric base material, and the exposed edge surface The electroosmosis of the ink is used to form a controlled liquid ink portion on the first electrode, particularly on the tip end thereof.

The liquid ink in this controlled liquid ink section is
Broadly speaking, there are four methods for sequentially depositing ink on a recording medium such as paper in synchronization with an input signal voltage and recording an ink image corresponding to the input signal on the recording medium.

The first method is a contact method in which a recording medium is brought into direct contact with a liquid ink portion to adhere liquid ink to the recording medium.

The second method is an electroosmotic flying method in which the recording medium is placed at an appropriate distance from the liquid ink section, and the liquid ink is deposited by flying from the liquid ink section using electroosmotic pressure.

In the third method, in the first and second methods described above, a counter electrode is installed on the surface opposite to the liquid ink portion of the recording medium, and a voltage is applied between this counter electrode and the above-mentioned first electrode. This is an ink adhesion assisting method in which ink adhesion to the recording medium is assisted by an electric field.

A fourth method is to arrange a recording body at an appropriate distance from the liquid ink section, and to install a counter electrode on the side of the recording body opposite to the liquid ink section, and to connect this counter electrode to the first This is a Coulomb force ejection method in which a high voltage is applied between the ink and the electrodes, and the liquid ink is forcibly ejected and adhered from the liquid ink portion to the recording medium using Coulomb force.

In any of these methods, in order to record and reproduce good images, a liquid ink portion must be selectively and independently formed on the first electrode tip side in response to each applied signal voltage. No.

However, in this type of recording apparatus, when a so-called on signal voltage modulated by an input image signal for forming a liquid ink portion to be recorded on a plurality of adjacent first electrodes is simultaneously applied. , the amount of ink in the liquid ink portion to be recorded increases abnormally compared to other cases, and the liquid ink portion is not formed independently corresponding to the tip of the first electrode, and the on-signal voltage is It is connected to the tips of adjacent electrodes to which an applied voltage is applied, and is formed into a band shape.

Therefore, the ink recording density on the recording paper, which is the recording medium, is abnormally high in the above case compared to other cases, and the ink recording does not separate into dots but instead becomes band-like. , it was found that the recorded image quality was significantly reduced.

SUMMARY OF THE INVENTION An object of the present invention is to provide an improved electroosmotic ink recording apparatus that solves the problems in principle of the conventional apparatus as described above.

To explain the present invention more specifically, in various electroosmotic ink recording devices based on the above-mentioned principle, the signal voltage is modulated by an input image signal corresponding to the density of the ink to be recorded, and the liquid ink portion is An on-signal voltage that modulates the amount of ink, such as formation and disappearance, and a constant off-voltage that causes the liquid ink to disappear or stop its formation, regardless of the input image signal. and the first electrodes to which the on-signal voltage is applied are selected in a predetermined order when recording corresponding unit pixels on the recording medium through the first electrodes. and the off-voltage is applied to at least the other first electrodes adjacent to each of the selected first electrodes, the on-off voltage corresponding to each of the selected first electrodes is applied. A means is provided for recording an ink image corresponding to the input image signal on the recording medium line-sequentially by applying a voltage signal in a time-division manner and recording each unit pixel in ink on the recording medium dot-sequentially. Found in electroosmotic ink recording devices.

An embodiment of the present invention will be described in detail below. FIG. 1 is a diagram showing a perspective partial structure and an electrical connection method of an embodiment of an improved electroosmotic ink recording device according to the present invention.

The ink recording head is shown as a representative example of the fifth configuration described above, and the ink recording method is shown as a representative example of the first contact method.

Furthermore, in this example, each unit pixel is recorded in ink corresponding to one of the recording electrodes, which is the first electrode, and the recording electrodes are one each of odd-numbered and even-numbered electrodes, so a total of two recording electrodes form one block. A case in which a is formed is exemplified.

In FIG. 1, 100 is an ink recording head, and its main components include first electrodes E ₁ , E ₂ , _{E 3 .}
A supporting substrate 10 having E _{o-1 and} E _o , a porous film 4 made of a solid dielectric film having a two-dimensional extent
0, includes a mesh electrode 50 as a second electrode placed on this membrane. One edge 12 of the support substrate 10,
That is, recording electrodes E ₁ , E ₂ ... one tip of E _o
A recording paper 500, which is a medium for ink recording, is pressed against the E ₁ ′, E ₂ ′, . . . E _o ′ side by a paper feed roller 600, and the electrode ends E ₁ ′, E ₂ ′, . Liquid ink is attached and recorded on the recording paper 500 from a liquid ink portion controlled by a so-called signal voltage formed on _{the o} ' side. On the surface of the support substrate 10, recording electrodes
E ₁ ...Outer edge portions 12', 12'' of the arrangement range of E _o
In order to prevent unnecessary ink from adhering to the recording paper 500, the edges 12' and 12'' are included at least,
and an auxiliary electrode A ₀ circumscribing the recording electrodes E ₁ , E _o with an appropriate distance (preferably recording electrodes E ₁ , E ₂ . . . the same or approximately the same distance as the electrode gap of E _o ),
A ₀ ′ is set.

External input image signal 1 to be recorded in ink
is converted into a line-sequential signal and stored in the serial/parallel conversion circuit 2. The converted and accumulated signals are D/A,
It is supplied in parallel to the drive circuit 3 including an A/D converter, etc., and corresponding to the input image signal 1, the electrode ends E ₁ '
_Amplitude modulation, pulse width modulation, or pulse width amplitude modulated on-voltage signals V _{1 ,} V ₂ .
V _o is formed. These on-voltage signals V ₁ , V ₂ ...
V _o is the switch S ₁ , S ₂ ...S _o of the switch circuit 4
At the same time, an off-voltage V _B is applied to the b-terminals from the off-voltage circuit 6, and the electrode ends E ₁ ', are applied independently of the input image signal.
It has the role of preventing, eliminating or stopping the formation of a liquid ink portion on E ₂ ′...E _o ′.

The switch circuit 4, together with the serial/parallel converter circuit 2, the drive circuit 3, the paper feed driver 7 such as a pulse motor, etc., receives a synchronous pulse from the synchronous pulse circuit 5, and the switches S ₁ , S ₂ . . . S _o perform synchronous control. be done. and the second
electrode 50 and recording electrodes E ₁ , E ₂ . . . which are the first electrodes.
…A voltage is applied between E _o , but generally the on-voltage signal V _r to be recorded in ink at a certain moment
(where r is an integer of n>r>1) is applied to the r-th recording electrode E _r , the off-voltage V _B is applied to at least the recording electrodes E _r-1 and E _r+1 on both sides. The switch circuit is controlled so that the off voltage is always applied to both sides of the electrode to which the on voltage signal is applied, so that the off voltage V _B is applied to E _r at the next moment, and this is repeated. As a result, the electrodes E ₁ , E ₂ ...E _r ...
Voltage signals V ₁ , V ₂ ……V _r …… by E _o-1 , E _o
Line sequential ink recording corresponding to V _o-1 and V _o is performed.

An attraction voltage V _A is constantly applied to the auxiliary electrodes A ₀ and A ₀ ' between the auxiliary voltage circuit 8 and the electrode 50, and the edge 1
The liquid ink seeped into the 2' and 12'' portions is always sucked up to the electrode 50 side through the porous membrane 40.The off-voltage _VB is selected so as to prevent and extinguish the controlled liquid ink portions. Under normal operating conditions, V _A has the same polarity as V _B and the amplitude is set to be equal to or close to V _B , so E ₁ and E _o are also equal to E _r as described above.
The operating conditions can be satisfied.

Thus, based on the operating conditions described above, the electrodes E ₁ ,
...E _r ...On signal voltage V ₁ to E _o , ...V _r ...V _o
By alternately switching and applying a constant off-voltage V _B and S ₁ ...S _r ...S _o , the image is printed on the recording paper 500 in binary values corresponding to the input image signal, or in shading including halftones. Ink recording is performed line sequentially.

Based on the above principle, electrodes E ₁ , E ₂ , E ₃ ...
A simple and effective operation method for performing line sequential recording corresponding to the signal voltages of V ₁ , V ₂ , V ₃ ...V _{o -1 ,} V _o by E o-1 and E o is as follows: As illustrated in Fig. 1, the odd numbered switches S ₁ , S ₃ , S _{5 .} . . are connected to the a side, and the ON signal voltages V ₁ , V ₃ , V ₅ .
are selectively applied to the odd-numbered recording electrodes E ₁ , E ₃ , E _{5 .} . . , respectively, and the even-numbered switches S ₂ , S ₄ ,
S ₆ ... is connected to the b side and the off voltage V _B is applied to the even numbered electrodes E ₂ , E ₄ , E ₆ ..., and at the next moment, the odd numbered switch is connected to the b side. Apply the off voltage V _B to the odd numbered recording electrodes E ₁ , E ₃ , E ₅ . . . and connect the corner numbered switches to the a side to apply the on signal voltages V ₂ , V ₄ , V ₆ . It is to apply. During this time, if the paper feed by the paper feed driver 7 is stopped, the ink to be recorded in line sequentially, V ₁ , V ₂ , V ₃ . . .
...The on-signal voltages V _{o -1} and V _o are recorded in ink line sequentially by double writing. By repeating this operation sequentially, line sequentially,
Characters, figures, images, etc. can be recorded in ink using binary or halftone display.

FIG. 2 is a diagram showing signal voltage relationships of various parts showing one embodiment of the above-mentioned ink recording apparatus according to the present invention.

In Figure 2, A ₀ , E ₁ , E ₂ ... E _r-1 , E _r ,
E _r+1 ...E _o-1 , E _o , A ₀ , A ₀ ', P represent the voltage pulses applied to each of the recording electrode, auxiliary electrode, and paper feed driver along with time t (horizontal axis), No mark indicates the off-voltage V _B pulse, and the shaded area indicates the on-signal voltage V ₁ , V ₂ , ... V _r-1 , V _r , V _r+1 ... applied to each electrode.
V _o-1 and V _o are shown, and the respective vertical axes represent the magnitude of voltage amplitude. Also, the polarity of the on signal voltage is + voltage,
-The direction of the diagonal line is changed depending on the voltage.

Generally, in this type of ink recording device, the liquid ink often uses a material that electro-osmoses into the surface of the support substrate 10 and the porous membrane 40 in the direction of the negative electrode. The voltage V _A and the off-voltage V _B are shown as positive voltages with respect to the second electrode 50 (therefore, the electrode 50 is negative). In addition, the relationship between the polarity and amplitude of the on-signal voltages E ₁ , E ₂ ...E _r ...E _o-1 , E _o and the ink recording density is that when a negative voltage pulse is used, the recording density increases as the amplitude increases. increases, and when the voltage is zero or even a positive voltage pulse, the recording density becomes zero, or the recording density decreases as the amplitude increases, and the amplitude is equal to the off-voltage _VB .
For example, conditions such as V ₁ ' and V ₃ ' in FIG. 2 are selected so that ink recording is completely inhibited and the recording density becomes zero.

E ₁ in Figure 2 contains characters, figures, etc., so-called on,
Off binary display On signal voltage when recorded
An example of V ₁ is shown, in which a positive pulse V ₁ ′ represents an off state with a recording density of zero, and a negative pulse V ₁ ″ represents an on state with a high density.

When recording and displaying a halftone image using a negative pulse with an on-signal voltage V ₂ of zero volts or less, E 2 in Fig. ₂ shows the on-signal voltage V ₃ from negative polarity to E ₃ in Fig. 2. A case is illustrated in which the polarity is further transferred to positive polarity to expand the recording density range of a halftone image and improve the quality of the recorded image.

On-signal voltage V ₁ , V ₂ , V ₃ ...V _r ...V _o-1 ,
When transferring V _o to positive polarity, its maximum amplitude is usually
It is desirable to select the amplitudes of the off-voltages V _B to be equal.

In Fig. 2, the case where E _r and E _o are odd numbers is illustrated, but when the time-division driving period, that is, the line sequential recording period in this example is T ₀ , the time Ot<T
In half period (T ₀ /2) ₁ , E ₁ , E ₃ , ...E _r-2 ,
The odd-numbered recording electrodes of E _r ...E _o receive an on-voltage signal V ₁ for ink recording modulated by input signal 1,
V ₃ ...V _r-2 , V _r ...V _o , while E ₂ , E ₄ , ...
E _r-1 , E _{r+1 ...} E
V _B is applied.

In the next half cycle (T ₀ /2) _2, contrary to the above,
Odd-numbered recording electrodes have an off voltage V _B , even-numbered recording electrodes E ₂ ,
E ₄ ...E _r-1 , E _r+1 , ... E _o-1 has on-signal voltages V ₂ , V ₄ , ... V _r-1 , V _r+1 , modulated by input signal 1,
...V _o-1 is applied, and at t=T, the synchronization pulse P
The paper feed driver 7 is operated intermittently to feed the recording paper 500 by one line.

In this way, a total of two recording electrodes, an odd number and an even number, are connected to one
The corresponding signal voltages V ₁ , V ₂ ...V _r-1 , V _r , V _r+1 ...V _o-1 , V _o to be recorded in ink are alternately dot-sequentially in each block. In this example, the switching is performed line-sequentially by two time divisions.

FIG. 3 is a perspective partial structural diagram illustrating a specific operating state of the apparatus shown in FIG.

The recording electrodes E ₁ , E ₂ , E ₃ ..., which are the first electrodes, are
A groove 20 with a depth of 20 μm, a width of 50 μm, and a pitch of about 125 μm (electrode gap 75 μm) is provided on the surface 11 of the support substrate 10 such as a glass substrate, and the inner wall of the groove 20 is formed in advance.
_Cr is evaporated to a thickness of about 0.2 μm, and then
It is constructed by vapor-depositing Au to a thickness of about 2 μm in a specular shape. Similarly, Cr and Au were deposited on the auxiliary electrodes A ₀ and A ₀ ′.
The distance between the recording electrodes E ₁ and E _o is selected to be approximately 75 μm.

On the surface 11 is a porous membrane 4 such as a microporous membrane film made of cellulose nitrate, cellulose acetate, etc., with an average pore diameter of about 0.1 to 8 μm, a porosity of about 60 to 80%, and a thickness of about 40 to 200 μm.
0, one edge of which is 50 to 200μ from edge 12, 12'
They are arranged so as to form an exposed edge surface 30 with a displacement of about m, and the other edge side is sealed up to between the surface 11 and the groove 20 using a backflow sealant 60. The distance from the sealing agent 60 side to the exposed edge surface 30 side, that is, the width of the porous membrane 40, determines the pumping amount based on the extrusion and suction of the liquid ink 200 by electroosmosis, and is therefore selected to be as wide as, for example, 20 mm or more. The second electrode 50 is a liquid ink 200 permeable electrode, e.g.
A mesh electrode is used in which about 100 to 200 meshes of through holes are provided in a metal plate with a thickness of about 100 μm.

The liquid ink 200 is contained in an ink container 300, and is applied to a sponge using capillary action.
body 400, porous membrane 4 via mesh electrode 50
0 and impregnated. The liquid ink 200 is prepared by dissolving, for example, about 3 to 5% by weight of an oil-soluble dye in an organic solvent as well as necessary charge control agents and surfactants. , both are configured to electroosmose in the same electric field polar direction, for example, generally in the direction of the negative electrode, have a viscosity of 2 to 10 centipoise, and a resistivity of 10 ⁶ Ω.
cm or more, relative permittivity of 5 or more, electrical osmosis of 10 ^-5 cm ² /
A voltage of about V-sec is used.

A recording paper 500 is pressed against the edges 12, 12' by a paper feed roller 600 made of an elastic material such as rubber, and the paper is fed in a direction 501 by rotation thereof.

In FIG. 3a, the voltage application state for _one cycle of (T ₀ /2) in FIG. 2 is illustrated.

Since a positive voltage V _A is applied to the auxiliary electrode A ₀ , the liquid ink 200 spilling out onto the electrode A ₀ and further onto the edge 12' is transferred to the negative electrode via the porous membrane 40 as shown by an arrow 201. It is sucked up by electroosmosis to the second electrode 50 side of the barrel, and the recording paper 50 is drawn from the edge 12'.
Unnecessary ink adhesion to 0 is prevented. Even-numbered recording electrodes E ₂ , E ₄ , to which a positive off-voltage V _B is applied
. . . is the same, and the porous membrane 40 is
A porous membrane 4 is placed on the second electrode 50 side having a negative potential through the
The liquid ink 200 is sucked up as shown by the arrows 202 and 203 through the electrodes 202 and 203, and the liquid ink 200 is drawn up at the tips of the even numbered electrodes E ₂ ′ and E ₄ ′, respectively, to which _{V B} is applied.
disappears.

On the other hand, negative on-signal voltages V ₁ , V ₃ , V ₅ . . . modulated by input signal 1 are applied, and odd-numbered electrodes E ₁ , E ₃ , E ₅ . Liquid ink 200 electroosmoses from the second electrode 50 side that is at potential as shown by arrow 204 in the figure, and this liquid ink 200 is transferred to the side opposite to the backflow prevention agent 60, that is, the electrode tips E ₁ ′, E ₃ ′ , E ₅ ′... towards the side, the groove 20
is pushed out as shown by arrow 205.

Also, in the bonding gap 13 between the substrate surface and the porous membrane 40, an auxiliary electrode forming a positive electrode is also provided.
Electro-osmosis is carried out as shown by the arrow 206 from the A ₀ and even-numbered electrodes E ₂ , E ₄ , . . . toward the odd-numbered electrodes E ₁ , E ₃ , E ₅ . do. Liquid ink 20 due to the effect of this extrusion
0 has a spread at the edge of the porous membrane 40 on the exposed edge surface 30 side as illustrated in the figure, but the substrate surface 1
By electroosmosis of liquid ink 200 to 1,
The auxiliary electrode A ₀ is the positive electrode, and the even number electrodes E ₂ , E ₄ ...
... to the odd-numbered electrodes E ₁ , E ₂ , E ₃ . . . as negative electrodes as indicated by arrows 207. Due to this focusing aperture, the tips of the odd-numbered electrodes E ₁ ′, E ₃ ′,
At E ₅ '..., a liquid ink portion 210 is formed that is limited within the groove and is controlled in accordance with the amplitude of the on-signal voltages V ₁ , V ₂ , V ₃ .

Since this liquid ink portion 210 is in contact with the surface of the recording paper 500, ink adheres to the odd numbered electrodes.
E ₁ , E ₂ , E ₃ . . . correctly correspond to the electrode width and groove cross section, and the on-signal voltages V ₁ , V ₃ , V ₅ . Ink recording of pixels will be performed.

FIG. 3b shows the operating state during the (T ₀ /2) ₂ period of FIG. 2. Odd numbered electrodes E ₁ , E ₃ , E ₅ ...
is the off voltage from the on voltage signals V ₁ , V ₃ , V ₅ ...
V _B , while the even numbered electrodes E ₂ , E ₄ ,...
... are the on-voltage signals V ₂ and V ₄ from the off-voltage V _B , respectively.
It can be switched to...

Odd numbered electrode tips correspond to V ₁ , V ₃ , V ₅ ...
The liquid ink portions 210 formed at E ₁ ′, E ₃ ′, E ₅ ′... are _{electroosmotic} 202,
It disappears by sucking up the liquid ink 200 as shown by the arrow 203 based on 206 and 207. Liquid ink 200 is concentrated on the even numbered electrodes E ₂ , E ₄ .
By extrusion as shown in 05, the tips E ₂ , E ₄ ,...
Liquid ink portions 210' corresponding to the on-signal voltages V ₂ , V ₄ .

Thus, in half period (T ₀ /2) ₁ of one period where Ot<T, _the ink recording of each unit pixel by the odd numbered electrodes E ₁ , E ₃ , E ₅ . 2)
₂ , ink recording of unit pixels is performed using even numbered electrodes E ₂ , E ₄ , . . . . With this time-sharing recording,
In the state shown in FIG. 3c in which the paper is fed by the synchronization pulse P at t=T (that is, (T ₀ /2) ₁ in the next cycle of Tt<2T in FIG. 2), on the recording paper 500,
As illustrated in the figure, recording electrodes E ₁ , E ₂ , E ₃ . . .
It is possible to obtain an ink record 220 that is line-sequentially recorded in gradations corresponding to the on-signal voltages V ₁ , V ₂ , V _{3 ,} etc., and by such line-sequential operation, the desired ink image is recorded. can.

As described above, ink recording is performed by point-sequential time-division selection in such a manner that the off-voltage V _B is always applied to the recording electrodes corresponding to unit pixels on both sides of the recording electrode that records a unit pixel in ink. In the present invention based on the principle, since an electroosmotic convergence effect as shown by arrow 207 is always present at the unit pixel recording electrode to which the on-signal voltage is applied at the same time as the above-mentioned arrow 205, point-like heights with little bleeding are generated. It has the advantage of being able to perform high-resolution ink recording.

Further, an off-voltage V _B is periodically applied to the recording electrode to periodically reset it, and the recording electrode is reset at the arrow 2.
Since the suction action of the liquid ink 200 such as No. 03 occurs periodically, the operation is averaged, and there is an excellent effect that ink recording with stable density corresponding to the ON signal voltage can be performed.

In addition, since the extrusion and suction of the liquid ink 200 are periodically and alternately repeated, the tip of the electrode
E ₁ ′, E ₂ ′, E ₃ ′... are subjected to a kind of cleaning by the liquid ink 200, and the liquid ink 200
This has the advantage of preventing instability of operation due to drying, clogging, etc.

However, in the conventional device, recording electrodes E ₁ , E ₂ , E ₃
...E _r-1 , E _r , E _r+1 ... simultaneously on signal voltage
_Since V _{1 , V 2} , _{V 3 .} −V _r-1 , V _r −V _r+1 . However, these are not necessarily large, especially V _r V _r-1 , V _r V _r+1 , V _r V _r-1 V _r+1
In this case, the voltage difference becomes zero, and there are cases where the convergence effect 207 does not work at all or hardly. In these cases, the ink recording is not in the form of separate dots as shown at 220 in FIG. 3c, but in the form of a band extending over a plurality of unit pixels. In addition,
Since the liquid ink 200 is simultaneously pushed out from a plurality of recording electrodes adjacent to each other, the ink is easily pushed out and the ink is recorded in an abnormally high density. Also,
If a signal voltage that prevents ink recording occurs following these conditions, the amount of ink to be sucked is excessive and the ink suction 203 becomes insufficient. Further, if a signal voltage instructing ink recording comes after such ink recording inhibiting signal voltages continue, the desired ink extrusion 205 becomes difficult because excessive ink is sucked.

In this way, with conventional devices, the focusing effect is insufficient and the recorded image becomes an ink image that is a mixture of dots and bands.
Furthermore, due to the influence of the recording electrodes on both sides and the signal voltage of the first one, the ink recording density may not necessarily be the on-signal voltages V ₁ , V ₂ , V r-1 , V r-1 , V r-1 , V r-1 , V r-1 , V r-1 , V r-1 , V _r-1 , V _r-1 ,
It does not correspond to V _{r+1 .} . . and includes a problem that significantly degrades the recorded image quality.

According to the present invention, the above-mentioned problems are improved and an excellent effect is obtained.

In the above embodiments, time-division recording was performed for each of the two unit blocks of odd-numbered and even-numbered recording electrodes, but time-division recording can also be performed for a further increased number of unit blocks.

For example, when three recording electrodes E ₁ , E ₂ , E ₃ . . . are used as a block, the first block is
E ₁ , E ₂ , E ₃ , second block E ₄ , E ₅ , E ₆ ,
The third one is E ₇ , E ₈ , E ₉ , and so on, each block is made up of three lines, and the line sequential recording period T is (T/
3) Divide into 3 like ₁ , (T/3) ₂ , (T/3) ₃ ,
(T/3) ₁ , the first electrode E ₁ of each block,
On signal voltages V ₁ , V ₄ , V ₇ ... are applied to E ₄ , E ₇ ..., respectively.
, and the off-voltage V _B for the other electrodes. Similarly, (T/3) ₂ , the second electrode of each block
On signal voltage V ₂ , V ₅ , V ₈ ... on E ₂ , E ₅ , E ₈ ...
In (T/3) ₃ , the third electrodes E ₃ , E ₆ , E ₉ ...
By time-divisionally applying on-signal voltages V ₃ , V ₆ , V ₉ .

Therefore, when each block is generally composed of N recording electrodes, the line-sequential recording period _T0 is divided into N pieces,
It is sufficient to time-divisionally apply each on-signal voltage to the recording electrodes in accordance with the respective order within each block, and apply the off-voltage V _B to the other recording electrodes.
By doing so, the off voltage V _B is applied to at least the recording electrodes on both sides of the recording electrode to which the on signal voltage has been applied.

FIG. 4 is a diagram showing a signal voltage application method according to another embodiment of the ink recording apparatus according to the present invention. In this example, the case where the on-signal voltage is used to display figures, characters, etc. in binary format is exemplified.

For convenience of explanation, the above embodiment has been described on the assumption that the paper feeding time of the recording paper 500 by the synchronization pulse P is negligible, and that the ink adhesion 220 to the recording paper 500 during this paper feeding time is negligible. It's here.

However, during so-called high-speed recording in which the line-sequential recording period T ₀ is very small, unnecessary ink adhesion to the recording paper 500 during the paper feeding time T _P due to the synchronization pulse P cannot be ignored. For example, as shown in FIG. 3c, ink deposits 220 become difficult to separate into dots in the paper feed direction, and this trailing phenomenon may result in strips in the paper feed direction. In order to prevent such deterioration of recorded image quality, all the recording electrodes E _{1 ,} E ₂ . . . E _o-1 , E Applying an off-voltage V _B to _o , the tips of the recording electrodes E ₁ ′, E ₂ ′...
...Controlled liquid ink portion 21 at E _o-1 ′, E _o ′
0,210' can be forcibly suctioned and eliminated.

Furthermore, during high-speed recording, the time width of the on-signal voltage applied to each recording electrode in a time-division manner becomes narrow, so as mentioned above, the on-signal is sequentially switched in one direction to adjacent recording electrodes. According to this method, the operation of subsequent recording electrodes is affected by the history of operational transients of adjacent preceding electrodes, which can lead to a decrease in recorded image quality. This phenomenon is particularly noticeable when obtaining halftone ink recorded images.

As illustrated in FIG. 4, this improvement is achieved by adjusting the on-signal voltage to at least jump over adjacent recording electrodes in each block to be time-divisionally driven within the time-division drive period T ₀ =T- _TP . This is improved by time-division driving. In this case, care must be taken so that on-signal voltages are not applied periodically and continuously to adjacent recording electrodes between adjacent blocks. It is sufficient that this condition is selected so that the first and last recording electrodes in each block are not driven in a time-division manner consecutively.

When the number of recording electrodes included in each block is N, the number of blocks is R, and the total number of recording electrodes E ₁ , E ₂ . . . E _o-1 , E _o is n. ,
N5 electrodes, n=NR electrodes may be selected, and the time-division application period of the on-signal voltage to each recording electrode may be set to T ₀ /N. In this case, it is clear that when m unit pixels are recorded, n5m units, N=nmR.

Based on the above principle, for convenience of explanation, FIG. 4 is a representative example of the case where ink is recorded uniformly at high density on the entire surface of the recording paper 500, with N=5, and each block 1, 2, ...R, the first time-division application period (T ₀ /5) ₁ to the first recording electrodes E ₁ , E ₆ , E ₁₁ ...E _o-4, on-signal voltages V ₁ , V ₆ , _V11
...V _o-4 is applied to the third electrode E ₃ , E ₈ , E ₁₃ in the second period (T ₀ /5) _{2 ...} V ₃ , V ₈ , V ₁₃ ... to E _o-2 ...
V _o-2 at the fifth electrode in the third period (T ₀ /5) ₃
E ₅ , E ₁₀ , E ₁₅ ... E _o to V ₅ , V ₁₀ , V ₁₅ ... V _o ,
In the fourth period (T ₀ /5) ₄ , the second electrodes E ₂ , E ₇ ,
E ₁₂ ... E _o-3 , the fourth electrode E ₄ , E ₉ , E ₁₃ ... E _o-1 in the fifth period (T ₀ /5) ₅ , V ₄ , V ₉ , V ₁₃ ...
V _o-1 is applied, and the on-signal voltages V ₁ , V _{2 ,} . . . , _{V o} are applied to all the recording electrodes E ₁ , E ₂ , . According to this method, not only recording electrodes within each block but also adjacent recording electrodes of mutually adjacent blocks, for example, the first block and the second block, the R-1 block and the R-th block, for example,
No on-signal voltage is applied to E ₅ and E ₆ and E _o-5 and E _o-4 in continuous drive application cycles, thereby stabilizing the ink recording operation.

Thus, following the fifth period (T ₀ /5) ₅ , the paper is fed over a period of T _P by the synchronizing pulse P,
In such line sequential recording, the next line sequential recording period T
The process moves to t<2T, and the same operation is performed thereafter. Generally, the above-described controlled generation and disappearance of the liquid ink portion 210 occurs with a finite response time constant with respect to the on signal voltage and off voltage, and occurs with a delay.

Therefore, in high-speed recording, this delay cannot be ignored. Therefore, in consideration of the time constant of this delay, the generation of the synchronizing pulse P is delayed a little more than illustrated in the figure, and if the generation and disappearance of the ink portion 210 and paper feeding are accurately synchronized, clear ink with less trailing can be produced. It has the advantage of being able to record.

However, if the speed is further increased, the liquid ink section 210,
210' may become unsatisfactory in terms of time constant for generation and disappearance.

FIG. 5 shows a driving method according to an embodiment of a further improved ink recording apparatus according to the present invention. In this example, a time-division driving application method of N=6 is illustrated. be.

This example is intended to improve ink recording characteristics by taking recording response characteristics into consideration.

That is, following the time-division application _{of on-signal voltages V 1 ,} V _{2 . .} .
03 is applied, for example _, the same polarity as V _B and a pulse width T _b shorter than the application period T ₀ /6. The suction 203 is forcibly accelerated to reduce the suction time constant.

This method has the advantage that a clean ink adhesion 220 with less trailing can be obtained, and that high-speed recording can be performed.

Generally, according to time-division driving, the ON signal application period
The application time of the off-voltage V _B is long compared to T ₀ /N.

Therefore, if the amplitude of V _B is chosen to be large in order to reduce the suction time constant in the above-described operation method, excessive liquid ink 200 will be suctioned when no on-signal voltage is applied, and this suction 203 will cause the next on-signal voltage to increase. is applied, the liquid ink portion 210 by the extrusion 205,
The so-called extrusion time constant of 210' formation becomes long, and high-density ink deposition 220 may be difficult.

However, in this embodiment, the liquid ink 200
The amplitude of V _B is selected to be small enough that the extrusion 205 stops or the suction 203 is slightly performed.
Moreover, by applying an auxiliary off-pulse V _b with a sufficiently large amplitude to forcibly and instantaneously perform the desired suction 203, the above-mentioned problems can be improved, and the time constants of each of the extrusion 205 and suction 203 can be reduced. It has the advantage of reducing

Note that at least one of the amplitude |V _{b |} and the pulse width T _b of the auxiliary off-pulse V b is determined by the on-signal voltage V ₁ ,
V ₂ . . . amplitude of V _o (i.e., V 1 , V ₂ . . . V _o measured using the on-signal voltage potential, which is the so-called minimum potential relationship that does not cause ink adhesion 220 when liquid ink 200 is sucked ₂₀₃ and does not cause ink adhesion 220, as a reference potential. The absolute value of the potential difference, in the example shown in the figure, the above reference potential is at V _B , so it can be modulated by the on-signal voltage so that it decreases as |V ₁ , ₂ ... n-V _B | increases.However, the circuit From the viewpoint of preventing physical complexity, it is desirable to keep each value constant.

To reduce the time constant of extrusion 205, as illustrated in the figure, the time-division application period, so-called write period T ₀ /6, is narrower than the rising portion of each on-signal voltage V ₁ , V 2 . _. . V _o . has a pulse width T _a ,
It is effective to energize the extrusion 205 of the liquid ink 200 by superimposing an auxiliary on-pulse Va having a voltage polarity that causes the extrusion 205 of the liquid ink 200.

In this case, as exemplified by the on-signal voltage V ₁ ' in the figure, when the on-signal voltages V ₁ , V _{2 . .} . In order to prevent the off-state from being significantly disrupted and causing ink adhesion 220, consideration must be given to appropriately increasing the amplitude of the off-voltage V _b and appropriately setting the amplitude of V _a |V _a | and pulse width T _a It is.

Similarly to the auxiliary off-pulse V _{b ,} the auxiliary on-pulse V _a also turns on at least _one of the on-signal voltages V ₁ , V _{2 .} Increasing the modulation in response to the signal voltage improves the response characteristics of the ink deposit 220 in the low density region, while decreasing the modulation has the advantage of recording an ink image with strong contrast, but increases circuit complexity. From the point of view of preventing
It is desirable to keep it at a constant value.

In this example, since V _a is applied superimposed on V ₁ , V ₂ ...V _o , the amplitude of |V _a +V _1,2 ... _o | is determined by V ₁ , V ₂ ...V _o, respectively. There are variable benefits.
However, instead of this, the on signal voltages V ₁ , V ₂ ...
Regardless of V _o , the liquid ink 200 has a constant amplitude greater than the maximum amplitude of the on-signal voltage;
A fixed auxiliary pulse with a voltage polarity that promotes extrusion 205 and a pulse width T _a that is sufficiently smaller than the writing period T ₀ /6 is applied, followed by an on-signal voltage of T ₀ /6 − T _a . If the voltage is applied within the write time, the circuit configuration will be further simplified.

In addition, in the figure, the synchronization pulse P for paper feeding is different from that in the case of FIG.
The delay is delayed by T _pd in consideration of the extinction time constant of 10', but adjusting T _pd has the advantage that ink image recording with improved trailing phenomenon can be achieved.

The above has been explained by taking as an example the case where ink recording is performed corresponding to one recording electrode of a unit pixel, but when a unit pixel is operated by connecting multiple recording electrodes in parallel in order to record at low resolution. It is clear that the same principle can be used by treating these as a single recording electrode.

In actual operation, various voltages V ₁ , V ₂ ...
...The voltage range of V _o , V _B , V _a , and V _b is the same as that of the second electrode 5.
0 and the recording electrodes V ₁ , V ₂ . . . V _o , which are the first electrodes,
In order to prevent operational instability such as dielectric breakdown, it is preferable to appropriately select the pitch interval between adjacent recording electrodes so that the effective total electric field strength does not exceed 5 volts per 1 μm.

For example, the recording head 100 of FIGS.
With the above-mentioned material configuration, the porous membrane 40
Nitrocellulose microporous membrane filter (thickness 150 μm, average pore diameter 3 μmφ,
The width of the porous membrane 40 from the sealing agent 60 (porosity 80%) to the exposed edge surface 30 is approximately 20 mm, and the arrangement pitch of the recording electrodes E ₁ , _{E 2} .
When the width of the exposed edge surface 30 is 70 μm, the on-signal voltage V ₁ , V ₂ ...V _o is -100 V (ink recording), +250 V (ink non-recording) binary signal voltage, suction When voltage V _A and off voltage V _B are set to +250 V, ink recording of a unit pixel is within 5 msec, and with odd-even time division driving as shown in Figures 1 to 3, 1
With a line sequential recording speed of 10 msec per line,
Enables ink recording of binary characters and figures.

In the above explanation, aspects of the present invention have been explained by taking as an example the fifth configuration described at the beginning as the recording head 100, but it is possible that the first to fourth and other recording head configurations can operate based on the same concept. it is obvious.

Furthermore, as a recording method, the explanation has focused on the first contact method described at the beginning, but in FIGS. 1 and 3, the recording paper 500 as a recording medium is
2', or by configuring the paper feed roller 600 as a counter electrode and applying a voltage between the recording electrodes E ₁ , E ₂ , . . . E _o , It is also clear that ink recording can be performed using the same concept using the second electroosmotic flying method, the third ink adhesion assisting method, and the fourth Coulomb force flying method. Furthermore, in this explanation, the on-signal voltage is applied to each recording electrode in a unit block in a time-division manner, but the on-signal voltage is applied to multiple recording electrodes at the same time, and each unit pixel is It is also clear that it can be configured to perform simultaneous recording in a relationship in which off-voltage V _B is applied adjacently.

As described above in detail, the present invention is applicable to a relationship in which a constant off-voltage is always applied to a recording electrode adjacent to this recording electrode when recording a unit pixel with ink through a recording electrode that is a first electrode. The principle is that an on-signal voltage modulated by an input signal is applied to each of the recording electrodes in a time-division manner, and the unit pixels are recorded with ink on a recording medium dot-sequentially, thereby obtaining an ink image by line-sequential recording. It is in an electroosmotic ink recording device.

According to the present invention, it is possible to obtain a uniform ink image, operate stably, and improve operational difficulties such as ink clogging, and has great practical effects.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a perspective structure and a power supply system of an electroosmotic ink recording device in an embodiment of the present invention;
Fig. 2 is a diagram showing the signal relationship of each part of the device shown in Fig. 1;
Figures 3a, b, and c are perspective views of the apparatus shown in Figure 1 to explain the specific operating state of the apparatus, and Figure 4 shows a signal voltage application method of an electroosmotic ink recording apparatus in another embodiment. The figure shown in FIG. 5 is a diagram showing a signal voltage application method of the electroosmotic ink recording apparatus in still another embodiment. 1... Input image signal, 2... Serial-to-parallel conversion circuit, 3...
Drive circuit, 4... Switch circuit, 5... Synchronous pulse circuit, 6... Off voltage circuit, 7... Paper feed driver, 8...
Auxiliary voltage circuit, 10... Support substrate, 20... Electrode groove,
30...Exposed edge surface, 40...Porous membrane, 50...Second
electrode, 100... ink recording head, 200... liquid ink, 210, 210'... controlled liquid ink section, 220... ink adhesion, 300... ink container, 400... corpus cavernosum, 500... recording medium, 600
... Paper feed roller, E ₁ , E ₂ ... E _o ... First electrode,
V ₁ , V ₂ ... V _o ... On signal voltage, V _A ... Attraction voltage, V _B ... Off voltage.

Claims (1)

[Claims] 1. A device comprising: a plurality of arranged first electrodes, a solid dielectric material having a two-dimensional extent, a second electrode, and means for supplying liquid ink to the dielectric material. death,
selectively applying a signal voltage to the dielectric and the liquid ink via the first electrode and the second electrode, and electroosmoticing the liquid ink into the dielectric in response to the signal voltage; , a controlled liquid ink portion is selectively formed on each of the first electrodes, and the ink is attached and recorded on a recording medium, and the signal voltage is modulated by an input image signal to be recorded with the ink. and a constant off-voltage that causes the liquid ink portion to disappear or stop its formation, regardless of the input image signal. In ink recording of corresponding unit pixels on the recording medium through the respective first electrodes, the first electrodes to which the on-signal voltage is applied are time-divisionally applied in a predetermined order. selected, and the off-voltage is applied to at least another first electrode adjacent to each of the selected first electrodes. Means for recording an ink image corresponding to the input image signal on each of the recording media line-sequentially by sequentially time-divisionally applying an on-voltage signal of and recording each unit pixel with ink on the recording medium dot-sequentially. An electroosmotic ink recording device characterized by being provided with. 2. Electroosmosis according to claim 1, characterized in that the first electrode is divided into blocks each having a plurality of electrodes, and ink is recorded point-sequentially in unit pixels within each block. Ink recording device. 3 Point-sequential recording of unit pixels by the first electrode is as follows:
2. The electroosmotic ink recording apparatus according to claim 1, wherein the on-signal voltage is applied in a time-division manner over adjacent units or plurality of first electrodes. 4. Point-sequential recording of unit pixels in each block is performed by applying an on-signal voltage in a time-division manner by jumping over the adjacent unit or plural first electrodes, and applying the on-signal voltage to the first and last pixels in each block. 3. The electroosmotic ink recording apparatus according to claim 2, wherein the time-division application of the on-signal voltage to the first electrode is discontinuous. 5. Claim 2, characterized in that the number of first electrodes included in the block is 5 or more.
The electroosmotic ink recording device described in . 6. The recording medium is intermittently moved in accordance with the line-sequential recording cycle, and an off-voltage is applied to all of the first electrodes in synchronization with this movement. The electroosmotic ink recording device according to item 1, 2 or 3. 7. An auxiliary on-pulse having a width smaller than this pulse width at the rising edge of the on-signal voltage pulse applied to the first electrode in a time-division manner and having a relationship that promotes the formation of a liquid ink portion, and Following the falling portion, an auxiliary off-pulse that is in a relationship that promotes disappearance of the liquid ink portion and has a width smaller than the pulse width of the on-signal voltage pulse; An electroosmotic ink recording apparatus according to claim 1, 2 or 3, characterized in that a voltage pulse is applied. 8. The controlled liquid ink portion is formed on the tip end side of the first electrode, and an auxiliary electrode insulated from the first electrode is installed circumscribing the electrode tip arrangement surface; The electroosmotic ink according to claim 1, 2, or 3, wherein a fixed voltage having the same polarity as the off-voltage is applied between the auxiliary electrode and the second electrode. Recording device.