JP5018145B2 - Inkjet recording device - Google Patents

Description

  The present invention relates to an ink jet recording apparatus, and more particularly to an ink jet recording apparatus that records an image by causing ink droplets to fly toward a recording medium using electrical energy, mechanical energy, thermal energy, or the like.

  Taking an electrostatic discharge type ink jet head as an example, an ink jet head having a control electrode is arranged opposite to a recording medium, and a drive pulse is applied to the control electrode, whereby an ink droplet is charged by electrostatic force. The head is made to fly toward the recording medium and land on the recording medium, and an image is formed on the recording medium by applying a driving pulse based on an image signal to the control electrode.

  Such electrostatic discharge type inkjet heads are disclosed in, for example, Patent Documents 1 to 3.

Patent Document 1 discloses that the concentration of toner particles in the ejected ink is increased by attracting the toner particles in the ink to the ink ejection side by the migration electrode.
Japanese Patent Application Laid-Open No. 9-1223459 JP 2004-82380 A JP 2005-47073 A

  As described in Patent Document 1, in addition to the control electrode for ejecting ink, the toner density of the ejected ink is increased by the configuration in which the migration electrode is arranged behind the control electrode in the ink ejection direction, so that the ink is clear. An image is formed.

  However, the inkjet recording apparatus described in Patent Document 1 has the following problems.

  As a result of the consumption of the ink in which the color material particles are concentrated from the ink in the ink jet head, a phenomenon occurs in which the color material particle concentration in the ink decreases toward the downstream of the ink flow path. It is formed.

  An object of the present invention is to provide an ink jet recording apparatus capable of solving such problems and forming a high quality image with extremely little density unevenness.

The object is achieved by the following invention.
1.
An ink jet recording apparatus for causing ink containing charged particles to fly toward a recording medium, comprising: a first substrate having an opening for discharging ink; and a second substrate disposed to face the first substrate. Forming an ink flow path between the first substrate and the second substrate, forming a plurality of the openings along the direction of ink flow in the flow path, and In an ink jet recording apparatus having an electric field forming means for increasing the concentration of the charged particles in the ink flow path on the first substrate side by forming an electrophoretic electric field for causing particles to migrate to the first substrate side.
The electric field forming means applies a voltage between the first electrode provided on the first substrate, the second electrode provided on the second substrate, and the first electrode and the second electrode to generate an electrophoretic electric field. A first power source to be formed;
An ink jet recording apparatus, wherein the area of the first electrode is increased toward the downstream, whereby the ink concentration force of the electric field forming means is increased on the downstream side in the ink flow path than on the upstream side.
2.
An ink jet recording apparatus for causing ink containing charged particles to fly toward a recording medium, comprising: a first substrate having an opening for discharging ink; and a second substrate disposed to face the first substrate. Forming an ink flow path between the first substrate and the second substrate, forming a plurality of the openings along the direction of ink flow in the flow path, and In an ink jet recording apparatus having an electric field forming means for increasing the concentration of the charged particles in the ink flow path on the first substrate side by forming an electrophoretic electric field for causing particles to migrate to the first substrate side.
The electric field forming means applies a voltage between the first electrode provided on the first substrate, the second electrode provided on the second substrate, and the first electrode and the second electrode to generate an electrophoretic electric field. A first power source to be formed;
The second electrode is divided into a plurality of portions along the direction of the ink flow through the ink flow path, and the area of the divided second electrode is increased toward the downstream, whereby the ink concentration force of the electric field forming means is increased. Is set higher on the downstream side in the ink flow path than on the upstream side.
3.
An ink jet recording apparatus for causing ink containing charged particles to fly toward a recording medium, comprising: a first substrate having an opening for discharging ink; and a second substrate disposed to face the first substrate. Forming an ink flow path between the first substrate and the second substrate, forming a plurality of the openings along the direction of ink flow in the flow path, and In an ink jet recording apparatus having an electric field forming means for increasing the concentration of the charged particles in the ink flow path on the first substrate side by forming an electrophoretic electric field for causing particles to migrate to the first substrate side.
The electric field forming means applies a voltage between the first electrode provided on the first substrate, the second electrode provided on the second substrate, and the first electrode and the second electrode to generate an electrophoretic electric field. A first power source to be formed;
The ink-concentrating force of the electric field forming means is made higher on the downstream side in the ink flow path than on the upstream side by narrowing the distance between the first electrode and the second electrode toward the downstream side. Recording device.
4).
An ink jet recording apparatus for causing ink containing charged particles to fly toward a recording medium, comprising: a first substrate having an opening for discharging ink; and a second substrate disposed to face the first substrate. Forming an ink flow path between the first substrate and the second substrate, forming a plurality of the openings along the direction of ink flow in the flow path, and In an ink jet recording apparatus having an electric field forming means for increasing the concentration of the charged particles in the ink flow path on the first substrate side by forming an electrophoretic electric field for causing particles to migrate to the first substrate side.
The electric field forming means applies a voltage between the first electrode provided on the first substrate, the second electrode provided on the second substrate, and the first electrode and the second electrode to generate an electrophoretic electric field. A first power source to be formed;
An ink jet recording apparatus, wherein the ink concentration force of the electric field forming means is made higher on the downstream side in the ink flow path than on the upstream side by lowering the height of the ink flow path toward the downstream.
5.
5. The ink jet recording apparatus of item 4 , wherein the width of the ink flow path in the direction orthogonal to the direction of ink flow in the ink flow path is increased toward the downstream.
6).
6. The ink jet recording apparatus according to any one of 1 to 5, wherein ink is ejected by an electric field formed between a recording medium and the opening.
7).
7. The ink jet recording apparatus according to any one of 1 to 6, further comprising an ink guide that projects into the opening and guides ink discharge.
8).
The ink jet recording apparatus according to any one of 1 to 7, wherein the first electrode has a control electrode for discharging ink from the opening.
9.
9. The ink jet recording apparatus according to 8 , wherein the control electrode includes a row electrode or a column electrode.
10.
6. The ink jet recording apparatus according to any one of 1 to 5, wherein the ink is ejected by thermal energy.
11.
The ink jet recording apparatus according to any one of 1 to 5, wherein ink is ejected by mechanical energy.
12
The electric field forming means applies a voltage between the second electrode formed on the second substrate, the third electrode facing the first substrate across the recording medium, and the second electrode and the third electrode. The inkjet recording apparatus according to any one of 1 to 5, further comprising a second power source that forms the electrophoretic electric field.
13.
The electric field forming means includes a second electrode formed on the second substrate and a charging means for charging the recording medium, and the electric charge applied to the recording medium by the second electrode and the charging means. 6. The ink jet recording apparatus according to any one of 1 to 5 , wherein the electrophoretic electric field is formed in a flow path.
14
14. The ink jet recording apparatus according to any one of 1 to 13 , wherein the ink concentrating power is increased by increasing the intensity of the electrophoretic electric field toward the downstream.
15.
The ink-jet recording apparatus according to any one of the 1-14, characterized in that a plurality of said openings in a direction intersecting the flow of ink in the ink flow path.

  In the present invention, since the ink concentrating power is increased toward the downstream of the ink flow path, the concentration of the color material particles in the ink ejected from the inkjet head is increased, and the color material particle concentration in the downstream is favorably reduced. Thus, an ink jet recording apparatus capable of forming a high-quality image having a high density and a uniform image density is realized.

  Hereinafter, the present invention will be described by way of embodiments of the present invention, but the present invention is not limited to the embodiments.

  FIG. 1 is a partial cross-sectional view of an ink jet head (hereinafter referred to as a head) according to an embodiment of the present invention, FIG. 2 is a view showing an electrode, and FIG. 3 is a view showing an ink guide.

  The head 1 has an insulating substrate 10 as a first substrate and a head substrate 30 as a second substrate.

  On the insulating substrate 10, insulating layers 12, 14 and 16 are stacked in order from the bottom.

  A control electrode 13 as a first electrode between the insulating substrate 10 and the insulating layer 12, a control electrode 15 between the insulating layer 12 and the insulating layer 14, and a guard electrode 17 between the insulating layer 14 and the insulating layer 16. Are provided respectively. The control electrode 13 and the control electrode 15 are provided by forming electrode layers on both surfaces of the insulating layer 12, and the guard electrode 17 is provided by forming an electrode layer on the insulating layer 14.

  Openings 18 are provided in a matrix arrangement in a laminate composed of the insulating substrate 10 and the insulating layers 12, 14, and 16.

The matrix arrangement of the openings 18 enables high-speed and high-resolution printing.
As shown in FIG. 2, the control electrode 13 and the control electrode 15 as the first electrode are formed in a ring shape surrounding the opening 18, and the guard electrode 17 is opened in the ring-shaped portion where the control electrodes 13 and 15 are formed. And is provided so as to cover the entire surface excluding the opening. A predetermined voltage is applied to the guard electrode 17, and has a function of avoiding electric field interference between the control electrodes 13 and 15 to which a drive voltage is individually applied during operation.

  The head substrate 30 is provided with an ink guide 31 with an upper end formed in a pointed shape, and the ink guide 31 protrudes upward through the opening 18. The head substrate 30 and the insulating substrate 10 are coupled with a gap, and this gap is filled with the ink A and forms the ink flow path 40.

  A migration electrode 32 as a second electrode is provided on the bottom of the head substrate 30, and the entire bottom surface of the head substrate 30 is covered with a cover layer 33.

  The migration electrode 32 is formed so as to cover the entire surface of the head. The migration electrode 32 is maintained at a potential that forms an electric field that causes the charged color material particles B in the ink A to migrate toward the tip of the ink guide 31. For this purpose, a power source 34 is connected to the migration electrode 32 and, for example, a voltage of +300 V is applied.

The ink A contains charged (for example, plus) colorant particles B in a dispersed state, and the dispersion medium for dispersing the colorant particles B is a dielectric liquid having a high electrical resistivity, particularly 10 ¹⁰ Ωcm or more. Preferably there is. Use of a dispersion medium having a low electrical resistivity is not preferable because electrical conduction occurs between adjacent recording electrodes.

  The ink guides 31 are arranged in a matrix corresponding to the openings 18, but each ink guide has a groove 31 a at the tip as shown in FIG. 3.

  As shown in FIG. 1, the head 1 is arranged with a predetermined interval with respect to the recording medium P supported by the electrode 41.

  The recording medium P is maintained at a potential of a voltage (for example, minus) opposite to the drive voltage (for example, plus) of the control electrodes 13 and 15, for example, a potential of −1500V. For this purpose, a voltage is applied to the electrode 41 by the power source 43 or the recording medium P is charged by a corona charger as a charging means.

  In the standby state, the ink A fills the gap 18 </ b> A (formed by the opening 18) between the insulating substrate 10 and the ink guide 31 and the groove 31 a provided at the tip of the ink guide 31 by capillary action. .

  In a state before the printing operation, the color material particles B migrate toward the opening 18 side of the ink guide 31 by an electric field formed in the ink flow path 40 by the migration electrode 32 and the control electrode 13 to which no drive pulse is applied. Then, the colorant particle concentration of the ink A in the vicinity of the opening 18 is increased.

  Even during the printing operation, the colorant particle B migrates in the ink flow path 40 at the opening where ink is not ejected, and the ink filling the gap 18A and the groove 31A surrounding the ink guide 31 after ejection. The colorant particle concentration inside is kept high.

  The control electrodes 13 and 15 are arranged in a matrix as shown in FIG. 2, and the rows 13A, 13B, and 13C of the control electrodes 13 are individually connected to the drive circuits 13AE, 13BE, and 13CE, and are driven by drive pulses. .. 155E are individually connected to the drive circuit and driven by drive pulses.

  The head 1 is adjusted so as to eject ink droplets when a row driving pulse and a column driving pulse are simultaneously applied. The row driving pulse and the column driving pulse are almost equal and have a voltage of 100 to 500V.

  When a drive pulse is applied to the control electrodes 13 and 15, an electric field is formed between the recording medium P and the head 1, ink is ejected from the opening 18 by the action of electrostatic force, and the ink droplet DR is directed toward the recording medium P. Will fly and land and print. Along with printing, the color material particles B in the ink A are electrophoresed and move to the tip of the ink guide 31.

  The ink guide 31 shortens the ink droplet flight distance between the inkjet head 1 and the recording medium P and improves the landing accuracy of the ink droplet.

  In addition, since the pointed head is formed on the ink guide 31, the occurrence of satellites due to the tail cut of ink droplets during ink ejection is reduced, and the image quality is improved.

  The ink A flows in the ink flow path 40 as indicated by the arrow W. The direction of the flow indicated by the arrow W is the direction in which the ink A flows through a circulation path through a density adjusting device (not shown) that adjusts the density of the color material particles B in the ink A.

  As described above, in the process of printing, the color material density rises in the vicinity of the tip of the ink guide 31 and ink with high color material density is consumed. The color material concentration of the color decreases as it goes downstream.

  For this reason, in the inkjet head in which a plurality of openings 18 for discharging the ink A are formed along the direction W in which the ink A flows, there is a problem that the print density decreases and the image density becomes non-uniform toward the downstream.

  In the present invention, such a problem is solved by increasing the ink concentration force in the downstream portion of the head along the ink flow path 40 more than the concentration force in the upstream portion of the head.

  The ink concentration force refers to an action of increasing the concentration of the colorant particles B in the ink in the vicinity of the opening 18. As a means for increasing the ink concentration force, increasing the electric field strength in the ink flow path 40. Widening the migration range of charged particles.

Specific examples include the following embodiments.
(1) The voltage of the second electrode is set to be higher at the first position of the ink flow path 40 downstream opening 18 than at the second position of the ink flow path 40 upstream opening 18.

  By increasing the voltage of the migration electrode 32 as the second electrode downstream, the electric field strength in the ink flow path 40 increases downstream, and the color material particles B in the ink A in which the color material density has decreased due to printing are opened. The force to migrate toward the 18 side acts strongly, and the ink concentration force becomes higher as it goes downstream.

As a means for forming such an electric field intensity distribution, as shown in FIG. 4A, a resistor 32R is used as the migration electrode and the downstream end is connected to the power source 34 or as shown in FIG. 4B. In addition, it is possible to divide the migration electrode from downstream to upstream like 32a, 32b... 32n, and connect power sources 34a, 34b.
(2) The area of the first electrode or the second electrode is made larger at the first position downstream of the ink flow path 40 than at the second position upstream of the ink flow path 40.

  The areas of the control electrode 13 as the first electrode and the migration electrode 32 as the second electrode are increased toward the downstream.

  Means for increasing the area of the first electrode is as shown in FIG.

  By enlarging the downstream-side first-position electrode C1 from the upstream-side second-position ring-shaped electrode C2 formed around the opening, the migration range of the color material particles becomes wider toward the downstream, and the ink concentration. Power increases.

  In this example, the migration electrode is divided in a direction perpendicular to the direction W in which the ink flows, like the strip electrodes 32q, 32r,... 32t in FIG. The width h1 downstream of the strip electrode 3q, ... 32t is formed wider than the width h2 upstream.

By forming the migration electrode 32 in such a shape, the migration range of the color material particles is widened, and the ink concentration power is increased.
(3) The distance between the first electrode and the second electrode is made narrower at the downstream first position than at the upstream second position, as shown in FIG. A layer of the migration electrode 32 is formed on the inclined bottom surface.

  As a result of the distance between the control electrodes 13 and 15 and the migration electrode 32 becoming narrower downstream, the electric field strength formed by these electrodes in the ink flow path 40 becomes higher downstream, and the ink concentration power becomes higher downstream.

  Further, as shown in FIG. 7, the interval between the control electrodes 13 and 15 and the migration electrode 32 can be narrowed stepwise in the downstream direction.

  Further, as shown in FIG. 8, the distance between the control electrodes 13 and 15 and the migration electrode 32 is reduced by narrowing the height of the ink flow path 40, that is, the distance between the insulating substrate 10 and the head substrate 30 toward the downstream. The downstream is narrower, and the downstream ink concentration force can be increased.

  In the example of FIG. 8, the volume of the ink flow path 40 in the downstream is reduced, but in order to prevent the ink from overflowing, as shown in FIG. 9, the width of the ink flow path 40, that is, the direction W of ink flow. The downstream width L1 is formed wider than the upstream width L2.

  As is clear from FIG. 1, the electric field for moving the colorant particles toward the opening 18 in the ink flow path 40 is formed by these electrodes at the position where the control electrode 13 faces the migration electrode 32. The electric field is formed by the guard electrode 17 and the braking electrode 32 at a position where the guard electrode 17 faces the electrode 32.

  Therefore, the guard electrode 17 formed on the surface of the inkjet head 1 also constitutes the first electrode.

  It is possible to use a combination of the means (1) to (3).

  As described above, the matrix arrangement of the openings 18 and the control electrodes 13 and 15 enables high-speed and high-resolution printing. With such a configuration, a plurality of openings are formed along the ink flow direction W. 18 is arranged, and a plurality of openings 18 are also arranged in a direction intersecting the direction W.

  Due to the matrix arrangement of the openings 18, a plurality of openings 18 are arranged in a direction intersecting the direction W of the common ink flow path 40 (hereinafter referred to as a horizontal direction). Even when the ejection openings 18 and the non-ejection openings 18 coexist, a lateral ink flow occurs, and the high density portion and the low density portion are mixed to make the density of the color material particles uniform, and the image density. Unevenness can be prevented.

  In the example shown in FIGS. 8 and 9, printing is performed while the recording medium is conveyed in the direction W, that is, the direction of ink flow in the inkjet head 1.

  FIG. 10 is a schematic view of still another example of the embodiment of the present invention in which one row of a plurality of openings 18 arranged in the ink flow direction in the ink flow path is provided. FIG. FIG. 10B is a top view of the head 1, FIG. 10B is a view showing the ink flow path, and FIG. 10C is a side sectional view of the inkjet head.

  In the example of FIG. 10, the strength of the electric field formed by the migration electrode 32 is increased toward the downstream by decreasing the height of the ink flow path 40 toward the downstream, and thereby the ink concentration force at the downstream is higher than that at the upstream. is doing.

  As illustrated, by increasing the width of the ink flow path 40 toward the downstream side, the volume of the ink flow path 40 is substantially equal between the upstream and downstream sides, and the ink flow is made smooth.

  FIG. 11 shows still another example of the embodiment of the present invention in which the arrangement of the ink guide 31 is changed.

  In FIG. 1, the ink guide 31 is provided in the opening 18, but in FIG. 11, the ink guide 31 is provided along the ink discharge wall of the opening 18.

  Also in the example of FIG. 11, the ink ejected from the opening 18 is guided by the side surface of the ink guide 31 and ejected, and flies in a predetermined direction.

FIG. 12 shows still another example of the ink jet recording apparatus according to the embodiment of the present invention that ejects ink with thermal energy.
Corresponding to each of the openings 18, a heating element 50 is provided on the side opposite to the opening of the ink flow path 40.

  When the heat generating element 50 selectively generates heat based on the image data, ink is ejected from the openings 18 to form an image.

  Since the concentration of the colorant particles B in the ink A in the ink flow path 40 is high on the opening side 18, the high concentration ink is ejected from the opening 18 and a clear image is formed.

  Note that the present invention can also be used in an ink jet recording apparatus that ejects ink with mechanical energy using a mechanical / electrical conversion element such as a piezoelectric element instead of a heating element.

  FIG. 13 shows still another example of the embodiment of the present invention in which an electric field is formed in the ink flow path by the electrode supporting the recording material and the migration electrode, and the colorant particle concentration is increased on the opening side.

  A voltage that causes the colorant particles B to migrate to the opening 18 side is applied to the migration electrode 32 by the power supply 34, but the electrode 41 that supports the recording medium P is grounded. An electric field for migrating the colorant particles B is formed.

  As a variation of the example shown in FIG. 13, the back surface (upper surface in FIG. 12) of the recording material P is charged by a charging means such as a corona charger, and charges are applied to the back surface of the recording material P. It is also possible to form an electric field with the electrode 32.

  FIG. 14 shows still another example of the embodiment of the present invention in which the first substrate on which the ink ejection opening is formed and the second substrate on which the migration electrode is formed are formed by a common member 50.

  As shown in the drawing, the common member 50 constitutes the first substrate 10A in which the opening 18 for discharging the ink is formed and the second substrate 30A in which the migration electrode 32 is formed. The control electrodes 13 and 15 are formed on the first substrate 10A.

  The ink flow path 40 is formed in the member 50 by molding. The ink flow indicated by the arrow W is formed by a circulation path (not shown).

It is a fragmentary sectional view of the ink jet head concerning an embodiment of the invention. It is a figure which shows an electrode. It is a figure which shows an ink guide. It is a figure which shows an electrophoresis electrode. It is a figure which shows a control electrode and a migration electrode. 1 is a partial cross-sectional view of an inkjet head that is an example of an embodiment of the present invention. It is a fragmentary sectional view of the ink jet head which is other examples of an embodiment of the invention. It is a fragmentary sectional view of the inkjet head which is another example of embodiment of this invention. It is a top view of the inkjet head shown in FIG. It is a figure which shows the further another example of embodiment of this invention which provided the row | line | column of several opening. FIG. 10 is a view showing still another example of the embodiment of the present invention in which the arrangement of the ink guide 31 is changed. Another example of the ink jet recording apparatus according to the embodiment of the present invention that discharges ink with thermal energy will be described. FIG. 10 is a diagram showing still another example of the embodiment of the present invention in which an electric field is formed in an ink flow path by an electrode supporting a recording material and a migration electrode, and the colorant particle concentration is increased on the opening side. It is a figure which comprises the 1st board | substrate and the 2nd board | substrate with the common member, and shows the further another example of embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inkjet head 10 Insulating substrate 12, 14, 16 Insulating layer 13, 15 Control electrode 17 Guard electrode 18 Opening 30 Head substrate 31 Ink guide 32 Electrophoresis electrode 41 Counter electrode 42 Ink flow path

Claims (15)

An ink jet recording apparatus for causing ink containing charged particles to fly toward a recording medium, comprising: a first substrate having an opening for discharging ink; and a second substrate disposed to face the first substrate. Forming an ink flow path between the first substrate and the second substrate, forming a plurality of the openings along the direction of ink flow in the flow path, and In an ink jet recording apparatus having an electric field forming means for increasing the concentration of the charged particles in the ink flow path on the first substrate side by forming an electrophoretic electric field for causing particles to migrate to the first substrate side.
The electric field forming means applies a voltage between the first electrode provided on the first substrate, the second electrode provided on the second substrate, and the first electrode and the second electrode to generate an electrophoretic electric field. A first power source to be formed;
An ink jet recording apparatus, wherein the area of the first electrode is increased toward the downstream, whereby the ink concentration force of the electric field forming means is increased on the downstream side in the ink flow path than on the upstream side. An ink jet recording apparatus for causing ink containing charged particles to fly toward a recording medium, comprising: a first substrate having an opening for discharging ink; and a second substrate disposed to face the first substrate. Forming an ink flow path between the first substrate and the second substrate, forming a plurality of the openings along the direction of ink flow in the flow path, and In an ink jet recording apparatus having an electric field forming means for increasing the concentration of the charged particles in the ink flow path on the first substrate side by forming an electrophoretic electric field for causing particles to migrate to the first substrate side.
The electric field forming means applies a voltage between the first electrode provided on the first substrate, the second electrode provided on the second substrate, and the first electrode and the second electrode to generate an electrophoretic electric field. A first power source to be formed;
The second electrode is divided into a plurality of portions along the direction of the ink flow through the ink flow path, and the area of the divided second electrode is increased toward the downstream, whereby the ink concentration force of the electric field forming means is increased. Is set higher on the downstream side in the ink flow path than on the upstream side. An ink jet recording apparatus for causing ink containing charged particles to fly toward a recording medium, comprising: a first substrate having an opening for discharging ink; and a second substrate disposed to face the first substrate. Forming an ink flow path between the first substrate and the second substrate, forming a plurality of the openings along the direction of ink flow in the flow path, and In an ink jet recording apparatus having an electric field forming means for increasing the concentration of the charged particles in the ink flow path on the first substrate side by forming an electrophoretic electric field for causing particles to migrate to the first substrate side.
The electric field forming means applies a voltage between the first electrode provided on the first substrate, the second electrode provided on the second substrate, and the first electrode and the second electrode to generate an electrophoretic electric field. A first power source to be formed;
The ink-concentrating force of the electric field forming means is made higher on the downstream side in the ink flow path than on the upstream side by narrowing the distance between the first electrode and the second electrode toward the downstream side. Recording device. An ink jet recording apparatus for causing ink containing charged particles to fly toward a recording medium, comprising: a first substrate having an opening for discharging ink; and a second substrate disposed to face the first substrate. Forming an ink flow path between the first substrate and the second substrate, forming a plurality of the openings along the direction of ink flow in the flow path, and In an ink jet recording apparatus having an electric field forming means for increasing the concentration of the charged particles in the ink flow path on the first substrate side by forming an electrophoretic electric field for causing particles to migrate to the first substrate side.
The electric field forming means applies a voltage between the first electrode provided on the first substrate, the second electrode provided on the second substrate, and the first electrode and the second electrode to generate an electrophoretic electric field. A first power source to be formed;
An ink jet recording apparatus, wherein the ink concentration force of the electric field forming means is made higher on the downstream side in the ink flow path than on the upstream side by lowering the height of the ink flow path toward the downstream. The ink jet recording apparatus according to claim 4 , wherein the width of the ink flow path in a direction orthogonal to the direction of ink flow in the ink flow path is increased toward the downstream. An ink jet recording apparatus according to any one of claims 1-5, characterized by discharging ink by forming between said recording medium aperture field. An ink jet recording apparatus according to any one of claims 1-6, characterized in that it has an ink guide for guiding projecting, the ejection of ink to the opening. The first electrode is an ink jet recording apparatus according to any one of claims 1-7, characterized in that it comprises a control electrode to eject ink from said opening. The ink jet recording apparatus according to claim 8 , wherein the control electrode includes a row electrode or a column electrode. An ink jet recording apparatus according to any one of claims 1-5, characterized by discharging ink by thermal energy. An ink jet recording apparatus according to any one of claims 1-5, characterized by discharging ink by mechanical energy. The electric field forming means applies a voltage between the second electrode formed on the second substrate, the third electrode facing the first substrate across the recording medium, and the second electrode and the third electrode. an ink jet recording apparatus according to any one of claims 1-5, characterized in that it comprises a second current source that provides the electrophoresis field. The electric field forming means includes a second electrode formed on the second substrate and a charging means for charging the recording medium, and the electric charge applied to the recording medium by the second electrode and the charging means. an ink jet recording apparatus according to any one of claims 1-5, characterized in that the electrophoresis electric field in the channel is formed. Wherein by increasing the strength of the electrophoretic field toward the downstream, ink-jet recording apparatus according to any one of claims 1 to 13, characterized in that to increase the ink concentration force. The ink-jet recording apparatus according to any one of claims 1 to 14, characterized in that a plurality of said openings in a direction intersecting the flow of ink in the ink flow path.

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