JPS59194854A - Ink tank for ink jet printer - Google Patents

Abstract

PURPOSE:To stably discharge ink by preventing the exposure of the inlet of an ink conduit to air and also the generation of bubbles in ink by making a simple improvement on the bottom shape of an ink tank moving with the recording head. CONSTITUTION:A recession is provided on the bottom a subtank 5 provided to a carriage 4, and the tip of a tube having a filter 7 is positioned in the recession. The depth of the recession is made longer than the length of the filter 7, the sideward width of the recession is made smaller to an extent not to prevent the smooth intake of ink 6, and also the recession is slightly inclined for helping the inflow of ink. The natural evaporation of ink, the generation of bubbles due to the bilateral movement of the carriage 4, and the exposure of the filter 7 to air due to vigorous flow of ink are eliminated. Even when the whole of the bottom of the subtank 5 is suitably inclined, the same effects as aforesaid effects can be obtained.

Description

TECHNICAL FIELD The present invention relates to an ink tank for a printer, and more particularly to the structure of an ink tank for an ink jet printer that performs dot recording by ejecting ink droplets via a piezoelectric element.

2. Description of the Related Art A pressure pulse-controlled inkjet printer is known that performs dot recording by ejecting ink from a piezoelectric device continuously provided in an inkjet nozzle.

This type of inkjet printer has drawbacks such as the inability to control the tendency of ejected ink droplets, low ejection frequency, low ink ejection speed, and inability to maintain a large distance between the nozzle and the recording paper. However, unlike other methods, there is no need for high voltage, no need for pressure pumps, no need to collect ink, and the structure is overwhelmingly simplified and can be made smaller. Are suitable.

The first example of the ink supply system of a conventional printer of this type is
It is as shown in the figure. In FIG. 1, the reference numeral 1 indicates a nozzle, and this nozzle l is swollen at the tip of a piece element 2, which is a pressurizing means formed in the hollow. It is connected to one end of the tube 3. The other end of the tube 3 is immersed in ink 6 supplied in a sub-tank 5 provided at the rear end of the carriage 4.

A filter 7 is attached to the rear end Q of the tube 3.

One end of a flexible tube 9 that follows the movement of the carriage 4 is connected to the ink supply port 8 of the sub-tank 5, and a hollow needle 10 is attached to the other end of the flexible tube 9.

On the other hand, the reference numeral I2 is an ink cassette that houses a main ink tank 11. The main ink tank 11 is formed, for example, as a flexible bag, and the ink supply port I3 is provided at one end of the ink cassette 12. It is fitted into a rubber stopper 14 made of silicone rubber or the like.

Then, the needle 10 passes through the rubber stopper 14 and is inserted into the supply port 13.

Based on the above structure, the ink of the part that applies a pulse voltage corresponding to the recording control number to the piezo element 2 is jetted toward the recording paper I5 through the nozzle l, and dot recording is performed. It will be done.

In an inkjet printer with this structure,
As the ink is consumed, the ink in the sub-tank 5 decreases, the pressure inside is reduced, and the ink is sucked from the main ink tank 11 through the flexible tube 9 and supplied to the sub-tank 5.

Furthermore, when the carriage 4 moves left and right at high speed, the flexible tube 9 is shaken, and centrifugal force acts on the ink inside it, causing the ink to move along the sub-tank 5 side, and the ink is automatically supplied into the sub-tank. Ru.

On the other hand, there is an air layer 16 inside the sub-tank 5, and this air layer 16 has a buffering effect, absorbing instantaneous increases in ink pressure such as when the carriage turns, and minimizing the pressure applied to the nozzles. There is. This air layer is approximately 0.3
The degree of this is necessary.

However, if you continue to use it for a long time, leave it for a long time, or repeat these actions, the external temperature will also fluctuate, and the air in the air layer 16 will also expand.

Due to repeated contraction, the ink in the sub-tank 5 is often pushed back to the main tank 12 side, although it is a very small amount.

In addition, the ink in the sub tank 5 evaporates little by little from the ink supply port 8, or the dissolved air in the ink is removed and released, so the air capacity in the sub tank gradually increases and the ink water level decreases. Sometimes I let it happen.

In this way, the water level of the ink in the sub tank is lowered left and right (it is shaken and foamed).The filter 7 attached to the end of the tube 3 that guides the ink to the nozzle The filter 7 has the role of preventing bubbles from entering the pressure chambers inside the nozzle 1 or the piezo element 2 and preventing the normal ejection of ink.Also, as described above, this filter 7 has the role of preventing bubbles from entering the pressure chambers inside the nozzle 1 or the piezo element 2. As a result of high-speed movement from side to side, when the amount of ink remaining is low, the filter 7 often goes from immersed in the ink to exposed to the air.For this reason, this filter 7 has a highly hydrophilic property. It is desirable that various hydrophilic treatments are applied.

However, if the filter 7 that has been subjected to hydrophilic treatment is exposed to the air for a long time, for example if the machine is installed tilted, the hydrophilic effect will be reduced, and as a result, the filter 7 will become Even if the nozzle is immersed in the ink 6 again, the effective area of the ink introduction section will be narrowed by the air that adheres and becomes bubbles, preventing normal ejection of ink from the nozzle.

Purpose The present invention aims to eliminate such conventional drawbacks and provide an ink tank for an inkjet printer that can eject ink more stably.

First Embodiment Below, an embodiment according to the present invention will be explained in detail based on the drawings.In the drawings of the illustrated embodiment, the same parts as in FIG. 1 are given the same reference numerals. The explanation will be omitted.

FIG. 2 shows the first ink tank for a printer according to the present invention.
An example is shown below. In the same figure, the part indicated by the symbol I7 is
A recess is provided in the bottom surface of the subtan 5 provided on the carriage 4, and the tip of a tube having a filter 7 at its lower end is disposed therein. The four parts 17 have a depth that exceeds the length of the filter 7, and the side 1-IJ is narrow enough not to hinder the smooth suction of the ink 6, and has the purpose of assisting ink to flow into the four parts. As shown in the figure, it is configured to have a slight inclination.

With the four parts 17 configured as described above, the condition where the filter 7 is exposed to the air due to the occurrence of burrs and the intense flow of ink is eliminated, and the ink is ejected from the normal and stable nozzle. can be special.

FIG. 3 shows the second ink tank for a printer according to the present invention.
In this embodiment, the sub-tank 5 is provided at the top of the carriage 4, and the ink introduction tube 3 and the filter 7 attached to its tip are both placed horizontally at the bottom of the sub-tank 5. It is located in Further, the entire bottom of the sub-tank 5 is constructed as a slope with a suitable slope so that the filter 7 is located at the deepest part.

In a printer ink tank having such a structure, the filter 7 is disposed obliquely at the deepest part of the tank, so the possibility of inhaling bubbles or being exposed to the air as described above is significantly reduced. Effects equivalent to those of the first embodiment can be obtained.

Embodiment a;, 'i Figure 4 shows the third embodiment of the ink tank for a printer according to the present invention.
This shows an embodiment in which a sub-square shaped filter 7 is fixed to the deepest part of the four parts 17 provided at the bottom of the sub-tank 5, and an ink introduction tube is further installed in the filter 7. 3 is raised from the deepest part and fixed.

This embodiment G configured in this way not only can achieve the same effect as the first embodiment Q, but also
Compared to the case where the filter 7 is attached to the tip of a tube, the shape of the filter 7 can be designed and selected more freely, so the combination of the filter and the tube can be used at a lower cost than before.

Effects As described above, in the present invention, by making simple improvements to the shape of the ink tank for printers, it is possible to eliminate the drawback that normal ejection of ink is hindered by ink bubbles generated inside the tank. This has many effects, such as enabling more normal and stable ink ejection and providing a cheaper ink tank for printers than ever before.

[Brief explanation of the drawing]

FIG. 1 is a schematic explanatory diagram showing an ink supply system, FIG. 2 is a sectional view showing a first embodiment of the invention, FIG. 3 is a sectional view showing a second embodiment of the invention, and FIG. The figure is a sectional view showing a third embodiment of the present invention. l... Nozzle 3... Ink introduction tube 5... ° Sub-tank 7... Filter 12
... Ink cassette 16 ... Air layer 17 ...
Four parts

Claims (2)

[Claims] (1) In an ink tank for an ink jet printer that performs dot recording by applying a pulse voltage corresponding to a recording control signal to deform a piezoelectric element and causing ink droplets to fly, the bottom of the ink tank moves along with the recording head. An ink tank for an inkjet printer, characterized in that an ink tank for an inkjet printer is formed with an inclined or recessed part, and an input part of a conduit for guiding ink to the tip of a nozzle is disposed in the deepest part thereof. (2) The ink tank for an inkjet printer according to claim 1, further comprising a filter disposed at the deepest portion or at the inlet end.