WO2017130180A1 - Ink jet recording device - Google Patents

Abstract

Ink jet recording devices suffer from the problem that charging electrode deformation causes irregularities in the amount of charge applied to particles, thereby degrading print quality, and the problem that during use over a long period of time, the adhesion of contaminants and changes in shape reduce mounting position accuracy, thereby degrading print quality. In order to solve these problems, a print head is provided with a nozzle, an orifice and a charging electrode. The charging electrode is provided with: a block-shaped charging electrode block; a charging electrode back cover which is positioned between the charging electrode block and the orifice, and which affixes the charging electrode block; and a charging electrode front cover which is positioned on the opposite side of the charging electrode block from the charging electrode back cover, and which affixes the charging electrode block. The charging electrode block, the charging electrode back cover and the charging electrode front cover are configured so as to be integrated, and the charging electrode, the orifice and the nozzle are configured so as to be integrated.

Description

Inkjet recording device

The present invention relates to an ink jet recording apparatus, and more particularly to a print head unit.

The ink jet recording apparatus of the charge control system supplies ink to the nozzles in the print head by a pump, ejects ink from the orifice at the tip of the nozzle, charges the ink that is particleized during the flight, and according to the amount of charge It is a device that prints by ejecting ink. Ink that has not been used for printing is collected and collected by a pump. Ink charging is performed by applying a voltage to a charging electrode arranged at a position where ink ejected from the nozzles becomes particles. The charge amount is changed by changing the voltage value for each particle. Since the diameter of the ink to be formed into particles is about 0.1 mm, the shape of the charging electrode and the position where the charging electrode is arranged require high accuracy.

JP-A-9-193402 (Patent Document 1) is known as a prior art of a charge control type ink jet recording apparatus. In Patent Document 1, an orifice portion is easily received by receiving an elastic force from an elastic body 10 provided on a base to which the nozzle portion 1 is attached and applying a pressing force generated by the elastic force 10 to the orifice portion 4. An ink jet recording apparatus is disclosed in which the positioning of the nozzle 4 and the charging electrode 5 can be made unnecessary by providing the positioning unit 4a in the orifice unit 4.

JP-A-9-193402

The structure described in Patent Document 1 has the following problems.

One of them is that the charging electrode is a sheet metal, so it deforms when pressed by a spring. When the charging electrode is deformed, the amount of charge given to the particles becomes unstable and the print quality is deteriorated.

The other is that the structure in which the orifice and charging electrode are pressed against the nozzle body with an elastic body is used for a long period of time. That is.

Therefore, an object of the present invention is to provide an ink jet recording apparatus having a high printing position and a stable print quality.

The present invention has the following configuration in order to solve the above problems.

An ink jet recording apparatus comprising a control unit, an ink circulation unit, a head cable, and a print head, wherein the print head includes a nozzle that continuously atomizes and ejects ink, and a particle ink that is ejected by the nozzle An orifice through which particles pass, and a charging electrode for charging ink particles that have passed through the orifice, and the charging electrode is disposed between a block-shaped charging electrode block and the charging electrode block and the orifice. A charging electrode back cover that fixes the charging electrode block; and a charging electrode front cover that is disposed on the opposite side of the charging electrode block from the charging electrode back cover and fixes the charging electrode block. The electrode block, the charging electrode back cover, and the charging electrode front cover are integrated. Is configured, the charging electrode and the orifice and the nozzle is an ink jet recording apparatus constructed come together.

According to the present invention, it is possible to provide an ink jet recording apparatus with improved mounting position accuracy and stable print quality.

FIG. 2 is a diagram illustrating an example of the configuration and arrangement of a nozzle body, an orifice, and a charging electrode of the ink jet recording apparatus according to the first embodiment of the invention. It is a figure which shows the example of the whole inkjet recording device structure which concerns on one Example of this invention. FIG. 3 is a perspective view illustrating the configuration and arrangement of a nozzle, a nozzle base that adjusts the ejection direction of an ink beam from the nozzle, and a print head base of the inkjet recording apparatus according to the first embodiment of the invention. FIG. 3 is a top view illustrating the configuration and arrangement of the nozzles of the inkjet recording apparatus according to the first exemplary embodiment of the present invention, the nozzle base that adjusts the ejection direction of the ink beam from the nozzles, and the base of the print head. FIG. 3 is a side view illustrating the configuration and arrangement of the nozzles of the inkjet recording apparatus according to the first exemplary embodiment of the present invention, the nozzle base that adjusts the ejection direction of the ink beam from the nozzles, and the base of the print head. It is a perspective view which shows the nozzle of the inkjet recording device which concerns on Example 2 of this invention, the nozzle base which adjusts the ejection direction of the ink beam from a nozzle, and the structure and arrangement | positioning of a print head base.

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

FIG. 2 is a diagram illustrating an example of the overall configuration of the inkjet recording apparatus 100 according to an embodiment of the present invention.

The ink jet recording apparatus 100 includes a control unit 101 at the upper part of the apparatus main body, an ink circulation unit 102 at the lower part, a print head part 104 for printing on a printing object, and a head cable 103 for sending ink and electrical signals to the print head. Has been.

The control unit 101 has a power source, a substrate, and an operation panel. The control unit 101 supplies power necessary for printing by the ink jet recording apparatus, transmits various signals necessary for printing by the ink jet recording apparatus, receives signals from sensors outside the control unit, and the like. The control unit 101 also has an operation panel for operating the ink jet recording apparatus.

The ink circulation unit 102 includes an ink tank that stores ink used for printing, a pump that supplies ink from the ink tank to the print head unit 104, a pump that collects ink that has not been used for printing from the print head unit 104, and ink. Built-in viscometer to adjust viscosity.

The head cable 103 bundles and protects wiring and piping from the IJP apparatus main body, and connects the IJP apparatus main body and the print head unit 104.

The print head unit 104 forms particles on the ink supplied from the IJP apparatus main body, causes the ink to fly by an electric signal, and prints on the printing object.

In this embodiment, the configuration and arrangement of the nozzle portion, the orifice portion, and the charging electrode housed in the print head portion 104 of the inkjet recording apparatus 100, which is the point of the invention, will be mainly described.

Specifically, the configuration and arrangement of the orifice portion around the nozzle and the charging electrode will be described with reference to FIGS. 1, 3, 4, and 5.

FIG. 1 is a diagram illustrating an example of the configuration and arrangement of a nozzle body, an orifice, and a charging electrode of an ink jet recording apparatus according to Embodiment 1 of the present invention.

FIG. 3 is a perspective view showing the configuration and arrangement of the nozzle of the inkjet recording apparatus according to the first embodiment of the present invention, the nozzle base for adjusting the ejection direction of the ink beam from the nozzle, and the print head base.

FIG. 4 is a top view showing the configuration and arrangement of the nozzle of the inkjet recording apparatus according to the first embodiment of the present invention, the nozzle base for adjusting the ejection direction of the ink beam from the nozzle, and the base of the print head.

FIG. 5 is a side view showing the configuration and arrangement of the nozzle of the ink jet recording apparatus according to the first embodiment of the present invention, the nozzle base for adjusting the ejection direction of the ink beam from the nozzle, and the base of the print head.

As shown in FIG. 1, an electrostrictive element 2, a counterweight 3, an ink supply tube 4, and an ink recovery tube 5 are incorporated in the nozzle body 1.
The ink collection tube 5 is a tube for collecting the ink supplied to the nozzle body 1 with a pump in the ink tank when the apparatus is stopped.
The nozzle body 1 is assembled in a nozzle jacket 6 and the nozzle base is fixed with a nozzle body fixing screw 7.
For the nozzle body 1, an O-ring 8, an orifice 9, a charging electrode back cover 10b, a charging electrode block 10a, and a charging electrode front cover 10c are assembled in this order, and are fixed using four charging electrode / orifice fixing screws 11. To do. The charging electrode block 10a has a slit with a rectangular cross section at the center, and the ink beam passes through this slit.

Further, the charging electrode block 10a has a vertical slit having a rectangular cross section in a direction perpendicular to the direction in which the ink beam passes. This vertical slit is a slit whose longitudinal direction is the direction in which the ink beam travels on the upper surface side of the charging electrode block 10a in FIG. 1, and is provided to confirm the shape of the ink particles passing through the charging electrode block 10a. The cross-sectional area is larger than the slit through which the ink passes. For example, light is applied to the ink flying from the nozzle base 22 shown in FIG. 3 by an LED or the like, and it is confirmed from the vertical slit, thereby confirming whether the ink particles are appropriate.

The charging electrode block 10a is provided with a screw hole for fixing the charging wiring 12 with the charging wiring fixing screw 13, and the ink can be charged by applying a voltage to the charging electrode block 10a.
A part assembled with these configurations is called a nozzle kumi.

Since the orifice 9 is made of metal, the charging electrode back cover 10b and the charging electrode front cover 10c are made of an insulator in order to insulate the charging electrode block 10a from the orifice 9.

When performing printing, ink pressurized at a predetermined pressure is supplied from the ink supply tube 4 to the nozzle body 1, and ink is ejected from the ink ejection port at the center of the orifice 9. At this time, by applying a voltage to the electrostrictive element 2 to vibrate the vibrator in the nozzle body 1, the ink in the nozzle body 1 is vibrated, and the ink particles in the space in the charged electrode block 10a while flying. Turn into. The particleized ink is charged by a voltage applied to the charging electrode block 10a. Thereafter, the flying direction of the ink is determined by the electrostatic force generated in the high electric field forming unit (not shown), and the ink adheres to the printing material and printing is performed. Ink that has not been used for printing enters a collection pipe called a gutter and is collected in an ink tank by a pump. As described above, in order to collect ink that has not been used for printing, it is necessary to adjust the direction of the nozzle by the beam adjustment mechanism so that the ink beam is directed to the gutter. The beam adjustment mechanism will be described later.

As described above, when charging the ink with the charging electrode block 10a, it is important that the distance between the ink beam and the inner wall of the charging electrode block is constant. This is because if the distance between the ink beam and the charging electrode changes, the ink flying direction changes due to the change in the charge amount of the ink particles, and the print quality deteriorates.

The charging electrode back cover 10b has a hole in the center portion, and has a structure in which the convex portion of the charging electrode block 10a fits. Thereby, the charging electrode block 10a is fixed to the charging electrode back cover 10b.
Further, as shown in FIG. 1, the orifice-side surface of the charging electrode back cover 10 b has a structure having convex portions in four directions, and this convex portion is structured to fit into the four concave portions of the orifice 9. As a result, the orifice 9 is fixed to the charging electrode back cover 10b as well as the charging electrode block 10a.
Further, since the convex portion of the surface of the charging electrode block 10a on the charging electrode front cover 10c side fits into the hole in the central portion of the charging electrode front cover 10c, the charging electrode block 10a is fixed to the charging electrode front cover 10c.

As described above, the charging electrodes (10a, b, c) and the orifice 9 can all be integrated and fixed.

Furthermore, since the convex part of the surface of the orifice 9 on the nozzle body 1 side is fitted with the hole in the center of the nozzle body 1 via the O-ring 8, the nozzle body 1 is also fixed.

For this reason, the distance between the ion beam and the inner wall of the charging electrode block 10a is always constant, so that the ink can be stably charged and stable printing quality can be provided. Further, the adjustment of the flying direction of the ink beam is very simple.

Furthermore, since the charging electrode block 10a is a block body, the shape is stable even after repeated removal, and the distance from the ink beam can be kept constant.

Fig. 3, Fig. 4 and Fig. 5 show the state where the nozzle kumi is assembled to the nozzle base and the nozzle kumi is assembled to the base of the print head. The nozzle kumi is fixed to the nozzle base 14 with a nozzle jacket fixing screw 15. The nozzle base 14 is provided with a horizontal adjustment screw 16, a horizontal adjustment spring 17, a vertical adjustment screw 18, and a vertical adjustment spring 19 for adjusting the ejection direction of the ink beam. The nozzle kumi and nozzle base kumi are fixed to a base 22 serving as a base of the print head by nozzle base fixing screws 20 and 21.

Next, the ink beam adjustment mechanism will be described.
First, an adjustment method in the horizontal direction with respect to the surface of the base 22 of the print head will be described with reference to FIGS.

The horizontal adjustment screw 16 and the horizontal adjustment spring 17 are used for the horizontal adjustment of the ink beam. The horizontal adjustment mechanism is configured such that a horizontal adjustment screw 16 is passed through a horizontal adjustment spring 17 and the horizontal adjustment screw 16 is inserted into a screw hole of the nozzle base 14. The screw head side of the horizontal adjustment screw 16 passes through a notch at the top of the support provided on the base 22 of the print head. By rotating the horizontal adjustment screw 16, the distance between the notch portion of the base 22 and the nozzle base 14 is adjusted while receiving the reaction force of the horizontal adjustment spring 17. A cylindrical boss of the base 22 exists at a position close to the ink ejection port, and the boss serves as a fulcrum of the nozzle portion, and the horizontal direction of the ink beam can be arbitrarily determined by tightening or loosening the horizontal adjustment screw 16. Is possible. In adjusting the ink beam, the nozzle base fixing screws 20 and 21 are loosened. After the adjustment is completed, the nozzle base fixing screws 20 and 21 are tightened to fix the nozzle base 14.

Next, an adjustment method in the direction perpendicular to the surface of the base 22 of the print head will be described with reference to FIGS.

The vertical adjustment screw 18 and the vertical adjustment spring 19 are used for the vertical adjustment of the ink beam. The vertical adjustment mechanism is configured such that the vertical adjustment screw 18 is passed through the vertical adjustment spring 19 and the vertical adjustment screw 18 is inserted into the screw hole of the nozzle base 22. The notch of the nozzle jacket 6 is sandwiched between the screw head of the vertical adjustment screw 18 and the vertical adjustment spring 19, and the distance between the notch of the nozzle jacket 6 and the nozzle base 14 is adjusted by the reaction force of the vertical adjustment spring 19. The vertical direction of the ink beam can be arbitrarily determined by tightening or loosening the vertical adjustment screw 18 with a hollow circular boss (not shown) of the nozzle jacket 6 as a fulcrum. When adjusting the ink beam, the nozzle jacket fixing screw 15 is loosened, and after the adjustment is completed, the nozzle jacket fixing screw 15 is tightened to fix the nozzle base 14.

Since the charging electrode is integrated with the nozzle as a nozzle kumi, adjustment of the charging electrode becomes unnecessary when adjusting the ejection direction of the ink beam. Further, since the nozzle and the charging electrode are integrated, the mounting position accuracy is always high, and it is possible to provide stable printing quality. Further, by blocking the charging electrode, it is possible to prevent the deformation of the shape and to provide a stable print quality.

The present embodiment is characterized in that the head base portion 1 includes a print head portion 104 having two nozzle portions 2.
FIG. 6 is an example of a configuration diagram illustrating the print head unit 104 having two nozzle knuckles and a nozzle base.

In the print head unit 104 of FIG. 6, the description of the part having the same function as the configuration denoted by the same reference numeral shown in FIG. 1, FIG. 3, FIG. 4 and FIG. . Moreover, the thing with the apostrophe of the same code | symbol has shown the part of the added nozzle base cum.

In addition, the horizontal ink beam adjustment mechanism has a symmetrical structure between the two, thereby reducing the size of the print head. In addition, since the charging electrode block has a symmetrical structure, the charging wiring can be easily fixed.

As shown in FIG. 6, for adjusting the position of the charging electrode, two nozzle bases are installed on the base 22 of the print head. The problem when installing a plurality of nozzles in one print head is the variation in print quality. One of the causes of the variation in print quality is the charge amount of the ink beam ejected from the orifice. For example, when the distance between the ink beam and the inner wall surface of the charging electrode block 10a is different, the charge amount of the ink particles changes and the deflection amount of the ink particles changes. By increasing the accuracy of the distance between the inner wall surface of the charging electrode block 10a and the ink beam, the printing quality can be stabilized. In this embodiment, a mechanism for positioning each of the charging electrode front cover 10c, the charging electrode block 10a, and the charging electrode back cover 10b is provided to stabilize the charge amount of the ink particles. Even in the case where it is provided also in the nozzle kumi of the structure, it is possible to reduce variations in print quality for each nozzle. In particular, in the twin nozzle type in which printing is performed with a plurality of nozzles, the effect of the present application is more remarkable because the influence of variations in print quality for each nozzle is greater than in the case of a single nozzle.

Also, since it is not necessary to adjust the positional relationship between the orifice and the charging electrode, it is not necessary to provide an adjustment mechanism or the like unique to the charging electrode, and the print head can be downsized.

In this embodiment, the print head having two nozzle portions has been described. However, even if the print head has three or more nozzles, the same effect can be obtained by providing a similar mechanism.

DESCRIPTION OF SYMBOLS 1 ... Nozzle body, 2 ... Electrostrictive element, 3 ... Counterweight, 4 ... Ink supply tube, 5 ... Ink collection tube, 6 ... Nozzle jacket, 7 ... Nozzle Body fixing screw, 8 ... O-ring, 9 ... Orifice, 10a ... Charging electrode block, 10b ... Charging electrode back cover, 10c ... Charging electrode front cover, 11 ... Charging electrode Orifice fixing screw, 12 ... Charging wiring, 13 ... Charging wiring fixing screw, 14 ... Nozzle base, 15 ... Nozzle jacket fixing screw, 16 ... Horizontal adjustment screw, 17 ... Horizontal adjustment Spring, 18 ... Vertical adjustment screw, 19 ... Vertical adjustment spring, 20, 21 ... Nozzle base fixing screw, 22 ... Base, 100 ... Inkjet recording apparatus, 101 ... Control unit 102 ... ink circulation unit, 103 ... head cable 104 ... print head

Claims (7)

An ink jet recording apparatus comprising a control unit, an ink circulation unit, a head cable, and a print head,
The print head is
A nozzle for ejecting ink;
An orifice through which the particulate ink particles ejected by the nozzle pass;
A charging electrode for charging ink particles that have passed through the orifice;
With
The charging electrode includes a block-shaped charging electrode block, a charging electrode back cover that is disposed between the charging electrode block and the orifice, and fixes the charging electrode block; and the charging electrode back with respect to the charging electrode block A charging electrode front cover that is disposed on the opposite side of the cover and fixes the charging electrode block; and the charging electrode block, the charging electrode back cover, and the charging electrode front cover are configured integrally.
An ink jet recording apparatus in which the charging electrode, the orifice, and the nozzle are configured integrally. The inkjet recording apparatus according to claim 1,
The inkjet recording apparatus, wherein the charging electrode, the orifice, and the nozzle are fixed by the charging electrode back cover. The inkjet recording apparatus according to claim 2,
2. The ink jet recording apparatus according to claim 1, wherein the charging electrode back cover is fixed by fitting convex portions provided on both sides thereof to the charging electrode block and the concave portion of the orifice. The inkjet recording apparatus according to claim 1,
The inkjet recording apparatus, wherein the charging electrode back cover is an insulator that insulates the charging electrode block from the orifice. The inkjet recording apparatus according to claim 1,
An ink jet recording apparatus, wherein the charging electrode block is provided with a slit for inspecting ink particles. The inkjet recording apparatus according to claim 1,
An inkjet recording apparatus comprising two or more combinations of the integrated charging electrode, the orifice and the nozzle. The inkjet recording apparatus according to claim 6,
2. The ink jet recording apparatus according to claim 1, wherein the combination of the two or more integrated charging electrodes and the orifices and the nozzles is axisymmetric.

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