JPS59214655A - Discharging method of bubble in ink jet recorder - Google Patents

Abstract

PURPOSE:To discharge and remove bubbles in a short time by small pressures by a method in which a pressure pulse is intermittently applied to the ink supply system of an ink jet head to cause bubbles in the ink jet head to discharge. CONSTITUTION:A release valve 20 is set in an ink supply path 2 from an ink tank 1 to an ink jet head 3. Ink liquid of a fixed pressure, pushed out of the ink tank 1, flows toward a discharge port 23 side by opening a ball valve 21 closed by a spring 22, while the balance between the reaction of the spring 22 and the resistance of the fluid is broken to give a vibration to the valve. Therefore, the ink fluid pressurized pulsatively is intermittently supplied to the ink jet head.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for discharging bubbles in an inkjet recording apparatus.

Figure 1 is a diagram showing the main parts of an example of an infusiera 1 to recording device to which the present invention is applied, in which ■ is an ink tank, 2 is an ink supply path, 3 is an inkjet head, and 4 is an ink tank. 1 is a recording paper, and as is well known, any desired image is recorded on the recording paper 4 by ejecting ink droplets from infusiers 1 to 3.

In the above-described inkjet recording apparatus, if air bubbles are mixed into the inkjet head 3, the air bubbles will cause the inkjet head 3 to be damaged when ink droplets are ejected.
Pressure waves are not sufficiently transmitted to the ink inside the printer, and ink droplets are not ejected regularly, resulting in poor printing quality. In order to solve such problems, various measures have been taken to discharge air bubbles from inkjet heads. For example, Japanese Patent Laid-Open No. 53-974
As disclosed in Japanese Patent No. 28, an ink storage container having a flammable ink bag and a suppression plate is provided, and the pressure in the ink supply system is reduced for a short period of time by manually pressing the suppression plate. The one that is raised to expel air bubbles,
Alternatively, as disclosed in Japanese Patent Application Laid-Open No. 56-162661, a manual suction pump is provided, and the suction pump sucks air bubbles in the inkjet head through a nozzle hole and discharges them. However, it has not always been easy to remove the bubbles.

Purpose The present invention was made in view of the above-mentioned circumstances.
The object of this invention is to provide a bubble evacuation method that can emit and remove air bubbles with lower pressure and in a shorter period of time.

Configuration The configuration of the present invention will be described below based on examples.

The forces that act on air bubbles in the ink supply system, mainly when removing air bubbles in the ink pressurized liquid chamber, are surface tension on the contact surface, buoyancy, and fluid pressure.For example, pressurizing the ink by pressing etc. In this case, the bubbles contract due to the pressure of the fluid (static pressure and dynamic pressure), and when pressurization is stopped, the bubbles expand again and return to their original state.
By repeating the expansion motion, the bubbles can be easily moved and discharged.

The present invention has been made based on the above-mentioned principle, and FIGS. 2 to 4 are main part configuration diagrams showing embodiments of the present invention, and the embodiment shown in FIG. valve 2
0 is installed in the ink supply path 2 shown in FIG. The ink liquid under constant pressure is applied to spring 2.
2 pushes aside the ball valve 21, which is closed, to open the valve and flow toward the discharge port 23, but at this time, the balance between the reaction force of the spring 22 and the resistance of the fluid is lost, giving vibration to the valve. As a result, ink liquid pressurized in pulses is intermittently supplied to the inkjet head. In the embodiment shown in FIG. 3, a reciprocating pump, a peristaltic pump 30, is disposed in the ink supply path 2. In the figure, 31 is a rotor, 32 is a roller, and 33 is a tube. The roller 32 rotates while crushing the tube 33 to pressurize the ink liquid in the tube, and when the roller 32 leaves the tube 33, no pressure is applied, thereby causing the pulsed ink to be pressurized to the inkjet head. Supply liquid intermittently. Further, the embodiment shown in FIG. 4 uses a diaphragm type pump 40.
In the figure, 41 is a diaphragm, 42 is an intake valve, 43 is a discharge valve, and 44 is a pressurized liquid chamber.The diaphragm 41 is vibrated by a camshaft or a crank (not shown), etc.
This applies intermittent pressure to the ink in the pressurized liquid chamber 44 in a pulsed manner. Note that the present invention is not limited to the above-mentioned embodiments, and for example, a voltage vibrator or the like may be installed in the ink supply path or in the ink tank, and the voltage vibrator may be turned on and off intermittently. You can. Further, as described above, when a pressurizing means is provided in the ink supply path, a sub-flow path exclusively for pressurizing may be provided as shown by the broken line in FIG. 1. Furthermore, even if negative pressure is applied intermittently from the outside of the nozzle, air bubbles within the inkjet head can be removed in the same way as described above. It is possible to apply intermittent negative pressure in pulses. FIG. 5 is a configuration diagram in that case, in which 5 is a reduced pressure flow path, 6
is a waste ink tank, and the negative pressure generating means as described above is provided in the pressure reducing channel 5.

As is clear from the above explanation, according to the present invention, air bubbles can be discharged with lower pressure and in a shorter time. In addition, air bubbles can be easily and reliably removed during initial ink filling.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a block diagram of main parts showing an example of an inkjet recording apparatus to which the present invention is applied, and FIGS. FIG. 5 is a diagram illustrating an example of an ink pressurizing means. FIG. 5 is a diagram illustrating a main part configuration of another example of an inkjet recording apparatus to which the present invention is applied. 1... Ink tank, 2... Ink supply path, 3...
・Inkjet head, 4...reduced pressure channel, 5...
Waste ink tank, 20...pump, 3o...peristaltic pump, 40...diaphragm type pump. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5

Claims (2)

[Claims] (1) In the inkjet recording apparatus), pressure pulses are intermittently applied to the ink supply system that supplies ink to the inkjet head to discharge air bubbles in the inkjet head. Air bubble evacuation method in an inkjet recording device. (2) Bubble discharge in an inkjet recording apparatus, characterized in that the air bubbles in the inkjet head are discharged by intermittently applying a negative pressure nozzle from the nozzle side of the inkjet head. Method.