JP4123897B2 - Inkjet nozzle - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an improvement of an inkjet nozzle suitable for an automatic drawing apparatus or the like.
[0002]
[Prior art]
Conventional ink jet nozzles for printers have a capability of a straight travel distance of ejected ink of about 2 to 3 mm.
[0003]
[Problems to be solved by the invention]
Therefore, materials that can be printed by conventional nozzles are limited to flat ones. For example, precise patterns and pictures could not be printed on uneven three-dimensional materials such as corrugated plates and brick-like wall materials. .
[0004]
SUMMARY OF THE INVENTION An object of the present invention is to provide an ink jet nozzle for a printer, in which a precise pattern or picture can be printed even on a material having a difference in height, and the straight travel distance of ejected ink is 10 cm or more.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, an inkjet nozzle according to the present invention is provided with a nozzle hole through which ink is ejected, an ink chamber for supplying pressurized ink to the nozzle hole, and the nozzle chamber. A needle valve that opens and closes the hole, a drive mechanism that drives the needle valve, a drive mechanism accommodation space that accommodates the drive mechanism, and an elastic membrane that separates the ink chamber from the drive mechanism accommodation space, The gist of the invention is that a pressure approximately equal to the pressure applied to the ink in the ink chamber is applied to the gas or liquid in the drive mechanism housing space.
[0006]
The inkjet nozzle of the present invention can have the following modified configuration.
(A) The ink chamber is connected to a pressurized ink tank through a circulation path.
(B) The drive mechanism is an electromagnetic drive type drive mechanism.
(C) The electromagnetic drive type drive mechanism is provided with a gap adjusting means between the nozzle hole and the needle valve.
(D) The electromagnetic drive type drive mechanism includes a movable iron core fixed to the needle valve, a fixed iron core provided to face the movable iron core, an electromagnetic solenoid that magnetizes the fixed iron core, and the fixed iron core and the movable iron core. It consists of a spring provided between the two.
(E) The electromagnetic drive type drive mechanism includes a permanent magnet fixed to the needle valve, a fixed iron core provided to face the permanent magnet, and an electromagnetic solenoid that magnetizes the fixed iron core.
(F) A pump is provided in the circulation path.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
1 and 2 show a schematic configuration of an embodiment of the inkjet nozzle of the present invention.
In the figure, an ink jet nozzle of the present invention has a nozzle hole 2 provided on the front surface of a substrate 1, an ink chamber 3 for supplying ink to the nozzle hole 2, an ink chamber 3, and the nozzle hole 2 at the tip. The needle valve 4 to be closed or opened, the movable iron core 8 fixed behind the needle valve, the fixed iron core 11 and the electromagnetic solenoid 12 provided opposite to the movable iron core 8, and the movable iron core 8 and the fixed iron core 11 are provided. A spring material 10 is provided, and the movable iron core 8, the spring material 10, the fixed iron core 11, and the electromagnetic solenoid 12 constitute an electromagnetic drive type drive mechanism for repeatedly closing and opening the needle valve 4 with respect to the nozzle hole 2.
[0008]
In order to prevent the ink in the ink chamber 3 from flowing out into the drive mechanism housing space 9 that houses the above drive mechanism, an elastic membrane 7 is provided so as to surround the needle valve 4, and an ink input passage is provided in the ink in the ink chamber 3. The pressure P is applied via 5.
[0009]
In order to prevent the pressurized ink from leaking from between the elastic diaphragm 7 and the needle valve 4, the pressure applied to the ink via the pressure passage 13 with respect to the gas or liquid in the drive mechanism housing space 9; A similar pressure P is applied.
[0010]
FIG. 1 shows that the needle valve 4 closes the nozzle hole 2. At this time, no current is passed through the solenoid 12, so that the movable iron core 8 and the subsequent needle valve 4 are moved by the action of the spring material 10. The nozzle hole 2 can be closed as a result of being pushed forward.
[0011]
On the other hand, FIG. 2 shows that the needle valve 4 opens the nozzle hole 2. At this time, a current flows through the solenoid 12, and the movable iron core 8 is adsorbed to the fixed iron core 11. Falls rearward and the nozzle hole 2 is opened.
[0012]
As described above, for example, by supplying a pulse current to the solenoid 12 and appropriately controlling it, the nozzle valve 2 can be opened and closed by the needle valve 4 and ink can be ejected to print on a three-dimensional material. . At this time, when the nozzle hole 2 was opened, the pressurized ink in the ink chamber 3 was vigorously discharged straight from the nozzle hole 2, and the straight travel distance could be over 10 cm.
[0013]
Further, since the pressures in the ink chamber 3 and the drive mechanism housing space 9 are applied to the same extent, the elastic diaphragm 7 is not applied with a biased distortion force, and the drive of the needle valve 4 is light and the closing and opening are repeated. It was also possible to increase the response speed.
[0014]
Further, the drive mechanism is preferably an electromagnetic drive type, and it is extremely difficult to employ a piezoelectric element as a drive mechanism for other mechanisms such as the needle valve 4 for the following reason.
[0015]
The expansion / contraction distance of the piezoelectric element is absolutely determined by the applied voltage. It is technically impossible to fix the needle valve to such a piezoelectric element and adjust the nozzle hole so as to close it conveniently. That is, if the expansion / contraction width of the piezoelectric element is too large, the needle valve and the surface around the nozzle hole collide, and the needle valve or the piezoelectric element coupled thereto is destroyed. On the other hand, if the expansion / contraction width is too small, there is a problem that ink always leaks from the nozzle hole. Therefore, the electromagnetic drive type drive mechanism is more practical than the piezoelectric element drive mechanism.
[0016]
Reference numeral 17 denotes a pressurized ink tank, which is connected to the ink chamber 3 via the circulation path 20, ink is supplied from the ink tank 17 to the ink input path 5, and ink discharged from the ink output path 6 passes through the pump 18. Then, the ink tank 17 is returned to. Circulating the pressurized ink in this way prevents separation and precipitation of the ink components, and helps to widen the range of ink types that can be used.
[0017]
A gap adjusting bolt 15 and a nut 16 are connected to the fixed iron core 11, and the position of the fixed iron core 11 can be changed by turning the nut 16. The change width is the distance between the needle valve 4 and the nozzle hole 2. That is, it becomes the change width of the nozzle gap, and this can be adjusted by the bolt 15. Reference numeral 14 denotes a screw rattling spring.
[0018]
The ink discharge amount can be controlled by adjusting the energization time of the solenoid 12, that is, the length of the opening time of the nozzle hole 2, but if the energization time is too long, the response speed of repeated opening and closing becomes slow. As a result, the print speed may be reduced.
[0019]
However, if the nozzle gap can be increased by the action of the gap adjusting bolt 15 and the nut 16, there is a merit that the amount of ink discharged can be increased without significantly increasing the energization time of the solenoid 12. You can increase the print speed without taking too much time.
[0020]
3 and 4 show another embodiment of the present invention. In this embodiment, a permanent magnet 28 is used instead of the movable iron core 8 in the embodiment of FIGS. 1 and 2, and the fixed iron core 21 and the electromagnetic solenoid 22 are provided without using the spring material 10 to drive the electromagnetic drive. The other structure is the same as that shown in FIG.
[0021]
FIG. 3 shows when the nozzle hole 2 is closed. At this time, as shown in the figure, the solenoid 22 is energized so that the fixed iron core 21 has a polarity repelling the polarity of the permanent magnet 28. As a result, the permanent magnet 28 and the needle valve 4 coupled thereto are pushed forward by the repulsive magnetic force to close the nozzle hole 2.
[0022]
FIG. 4 shows a state in which the nozzle hole 2 is opened. At this time, no current flows through the solenoid 22, or a current having a polarity opposite to the above flows, and the permanent magnet 28 is attracted to the fixed iron core 21. The needle valve 4 opens the nozzle hole 2.
[0023]
【The invention's effect】
As described above, according to the present invention, an ink jet nozzle capable of expanding the straight travel distance of ejected ink to 10 cm or more and enabling ink jet printing even on a three-dimensional material having a height difference. Can be provided.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of an entire embodiment of the present invention, showing a state when a nozzle is closed.
FIG. 2 is a partial view showing a state when the nozzle of the embodiment of FIG. 1 is opened.
FIG. 3 is a partial schematic configuration diagram of another embodiment of the present invention, showing a state when the nozzle is closed.
4 is a partial view showing a state when the nozzle of the embodiment of FIG. 3 is opened. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Base | substrate 2 Nozzle hole 3 Ink chamber 4 Needle valve 7 Elastic body diaphragm 8 Movable iron core 9 Drive mechanism accommodation space 11 Fixed iron core 12 Solenoid 17 Ink tank

Claims (7)

Nozzle holes from which ink is ejected;
An ink chamber for supplying pressurized ink to the nozzle holes;
A needle valve provided in the ink chamber for opening and closing the nozzle hole;
A drive mechanism for driving the needle valve;
A drive mechanism housing space for housing the drive mechanism;
An elastic membrane that separates the ink chamber from the drive mechanism housing space,
An inkjet nozzle configured to apply a pressure comparable to the pressure applied to the ink in the ink chamber to the gas or liquid in the drive mechanism housing space. 2. The inkjet nozzle according to claim 1, wherein the ink chamber is connected to a pressurized ink tank through a circulation path. The inkjet nozzle according to claim 1, wherein the drive mechanism is an electromagnetic drive type drive mechanism. 4. The ink jet nozzle according to claim 3, wherein the electromagnetic drive type driving mechanism is provided with a gap adjusting means between the nozzle hole and the needle valve. The electromagnetic drive type drive mechanism includes a movable iron core fixed to the needle valve, a fixed iron core provided opposite to the movable iron core, an electromagnetic solenoid that magnetizes the fixed iron core, and between the fixed iron core and the movable iron core. The ink jet nozzle according to claim 3, wherein the ink jet nozzle is provided with a spring provided on the surface. 4. The electromagnetic drive type driving mechanism includes a permanent magnet fixed to the needle valve, a fixed iron core provided to face the permanent magnet, and an electromagnetic solenoid for magnetizing the fixed iron core. The inkjet nozzle as described. The inkjet nozzle according to claim 2, wherein a pump is provided in the circulation path.

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