JPS59196263A - Liquid filter - Google Patents

Abstract

PURPOSE:To eliminate the generation of air bubbles, to enhance strength and to prevent clogging caused by partial detachment during adhesion, by forming a honey-comb configuration liquid filter by integrating a large number of tubes each having a fine communication bore bundled in a honey-comb configuration. CONSTITUTION:A filter 16 is molded by a method wherein several hundreds of glass fiber tubes 18 each having a communication bore 17 with a diameter (d) of about 10-50mum are bundled and subjected to thermal compression to eliminate mutual gaps between the fiber tubes as well as to integrate the same while the formed lotus root shaped one is cut into a proper length by a cutter. The aforementioned filter 16 has 20-800 per 1mm.<2> of communication bores and it is pref. that the relation of the diameter (d) the length L of each communication bore is L/d>=10. This filter 16 is well achieved in function as the filter used in an ink jet recording apparatus, prevented from partial detachment and has no fine gaps each having an acute angle of 30 deg.C or less for gathering air bubbles.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a liquid filter suitable for application to a recording device that performs recording using ink, such as a pen recorder or an inkjet recording device.

/ (Prior art) In general, in recording devices that record using ink, such as Ben recorders and inkjet recording devices, a filter is provided in the middle of the ink supply path that supplies ink from the ink container to the recording head. . FIG. 1 shows the vicinity of a recording head of a conventional inkjet recording apparatus. In the figure, reference numeral 1 denotes a cylindrical piezo element which compresses and deforms in response to electric pulses and ejects ink droplets 6 from a nozzle orifice 2.

Reference numeral 4 denotes a hard glass tube having the above-mentioned nozzle orifice 2 at its tip and further wrapped with the above-mentioned piezo element 1. 5 is a lead wire that transmits electric pulses to the piezo element 1, one of which is connected to the surface electrode of the cylindrical piezo element 1, and the other is connected to the end surface plating.
ih and connected to the inner electrode.

A flexible tube 6 is connected to an ink container (not shown), and is connected to the open end of the glass tube 4. 7 is a liquid filter, which is press-fitted into the tube 6. In the ink jet recording apparatus having the above structure, it is desirable that the filter 7 has the following functions.

1. The nozzle orifice with a diameter of several tens of micrometers prevents the intrusion of dust. 2. The nozzle orifice must be supplied with sufficient ink. 4. The piezo element 1 must not be deformed and the pressure that provides the power to eject the ink ii knee 5 must not be lost backwards. 5. The recording head is mounted on a carriage and reciprocated from side to side. Among other things, it is important to absorb all pressure fluctuations within the nozzle and keep the meniscus of the nozzle orifice in a stable state (the important thing is to prevent air bubbles from entering the nozzle orifice side. When the particles wrapped around the piezo element in the tube enter the pressure chamber, the efficiency of the piezo element 1 is significantly reduced due to its large pressure force.

Furthermore, if air bubbles are produced in the nozzle orifice 2, the flying direction of the ink droplets may change, minute droplets may be generated, causing multiple defective prints, and in the worst case scenario, the ink may not be ejected.

Therefore, JJJ, which prevents bubbles from entering the pressure chamber, is an essential requirement for stable operation of an inkjet recording apparatus.

On the other hand, the conventionally used filter 7, as shown in FIGS. 2A and 2B, is made by integrally molding polyethylene particles 8 by paving, and has various problems.

First, since it is made up of small particles, there is a risk that some of the particles may fall off when worn. This means that the filter itself, which prevents dust from entering, becomes a source of dust, clogging the recording head, and requires a high degree of consideration in management and process.

Also, the ink 9 is filled between the grains 8 and 8,
At this time, the acute angle portion 10 of 60° or less is inevitably crushed, and ink cannot enter here K. If such an acute angle portion 10 exists, the filter for preventing the intrusion of air bubbles contains air bubbles. Most of these bubbles can be removed by suction from the outside, but after many years of use, they are gradually released and enter the nozzle orifice.

(Purpose) The purpose of the present invention is to solve the above problems all at once.

(Example) FIG. 6 shows an inkjet recording apparatus according to an actual 11m example of the present invention.

In FIG. 6, numeral 11 is a recording head that discharges ink using a piezo element to perform ink recording, similar to the recording head shown in FIG. 1, 12 is a recording sheet for recording with ink, and 15 is a recording A carriage that moves the head back and forth; 14 is a sub-ink tank that supplies ink to the recording head; 15 is a supply pipe that supplies ink from the sub-ink tank 14 to the recording head; 16 is a filter that cuts out dust, bubbles, pressure, etc. show.

The recording head 1 is placed on the carriage 16 that moves back and forth in this way.
1 and a sub-ink tank 14 for supplying ink thereto are integrally provided.

This sub-ink tank 14 is connected to the main ink tank 1 by an ink supply tube 17 that moves back and forth. Pressure fluctuations caused by negative pressure are caused by sub-ink tank 1.
4 and the filter 16.

However, if the air layer 19 in the sub-ink tank 14 becomes pressurized due to a rise in temperature or a decrease in pressure in the surrounding environment, this pressure will spread to the recording head 11, making it impossible to eject ink normally.

Therefore, the main ink tank 1B is made of a flat and thin flexible bag structure to absorb pressure changes caused by the air layer 19 inside the sub ink tank 14. That is, the supply tube 1 is movable from the fixed main ink tank 18.
An inkjet recording device that receives ink supply at 7 and performs high-speed reciprocating motion on a carriage for recording is a sub-ink jet recording device that has an air layer that absorbs pressure fluctuations between IRs caused by the inertia of the ink in the supply tube 17. A tank is required, and the air layer must also absorb relatively slow pressure fluctuations caused by temperature increases inside the device. .

Since the load resistance of the recording head 11 and filter 16 is much larger than the load of the supply tube 17 and the main ink tank 18 having a flat, thin, flexible bag structure, the ink in the sub-ink tank 14 easily flows into the main ink tank 18.
The pressure inside the sub ink tank 14 is balanced. , the diameter of the discharge orifice of the iC0 head is generally:
The larger the number of air particles 19 in the ink tank 14 (11), which is 100 μm or less, the greater the effect of absorbing instantaneous pressure fluctuations. However,
On the other hand, the side effect of expansion and contraction due to temperature changes increases, and the capacity usually ranges from 0.3 cc to 0.8 cc.

However, even with this configuration, if air bubbles are scattered in the ink supply tube 7, the ink will not move smoothly. A communication opening is provided by a thin tube 20 having a small inner diameter.

Therefore, this structure constitutes a pseudo-closed system rather than a completely closed system. The outer end 20A of this thin tube 20 is used for the initial filling operation of ink into the sub-ink tank 14.
The ink level in 4 reaches the inner end 2OB of the thin tube 20, and the inside of the tube is also dripped with ink.

The ink is made specifically for inkjet, and its components include a solvent that is extremely difficult to evaporate, such as polyethylene glycol, so the ink inside the thin tube 20 does not completely evaporate even over a long period of time. Due to its surface tension and viscosity, the air layer 19 in the sub-ink tank 14 is disconnected from the atmosphere, forming a pseudo-closed system.

21 is a magnetic yoke of a linear motor that also serves as a sliding shaft; 22
26 is a frame and magnetic yoke, and 26 is a permanent magnet. Here, the carriage 16 reciprocates left and right on the magnetic yoke 21 due to the Fleming force acting between it and a coil (not shown).

Replenishment of ink from the main ink tank 18 to the recording head 11 occurs when the air layer 19 in the sub-ink tank 14 is reduced due to continuous ink surface tension, capillary action, or ink ejection. This is automatically performed by supplying ink from the main ink tank 18 as the pressure is reduced.

The aforementioned filter 16 is shown in FIG. 4 and has a lotus root-like structure as shown in FIG. This filter 16 is the fifth
As shown in the figure, several hundred glass fiber tubes 1B each having 17 communication holes with a diameter d of about 10 to 50 μn are bundled together, heat compressed to eliminate gaps between the fiber tubes, and made into a lotus root shape. It is cut to an appropriate length.

This filter 16 is 1111111 2U~800
It has a continuous hole, and the diameter d and length L of the communicating hole are 15.
(It is preferable that the l ratio is L/d≧10 in order to effectively perform the function as a filter.

The filter 16 has a structure in which a large number of fiber tubes 18 having fine communication holes 17 are integrally molded by heat compression so that there are no gaps between them, so it can be used as a filter for inkjet recording devices. This function is achieved well and there are no gaps.

It should be noted that the present invention is not limited to the above-mentioned embodiments, and for example, a more hydrophilic ceramic may be used as the material of the fiber tube. In addition, the fiber tube does not have to be cylindrical, but may be, for example, prismatic, and in this case, the length of the maximum side of the communicating hole of the prismatic tube is 2.
It is preferable that it is 0 to 50 μm and 8 degrees. Further, this filter may be used anywhere in the ink supply path from the ink tank to the recording head. Furthermore, the above filter can be widely applied not only to inkjet recording devices but also to, for example, pen recorders and other recording devices that perform recording using ink.

(Effects) As described above, according to the present invention, it is possible to provide a liquid filter that does not generate air bubbles, is strong, and does not cause clogging due to part of it falling off during installation. .

[Brief explanation of drawings]

Figure 1 is a perspective view of a conventional recording head, Figures 2(a) and (b) are enlarged views of filters, and Figure 6 is an enlarged view of a filter.
4 is an explanatory diagram of a filter used in this embodiment, and FIG. 5 is an explanatory diagram of the manufacturing process of the filter shown in FIG. 4. 11...φ Recording head 14 Ink tank 15... Supply pipe 16...-Filter 17...
...Communication hole 18...Glass fin (-pipe row 1 diagram too? (support) (α) (b)

Claims (1)

[Scope of Claims] 1) A liquid filter 2 in the form of a liquid filter, which is installed in the middle of an ink supply system, is substantially parallel to the supply system, and has a large number of fine communication holes.Claim 1: The described liquid filter is characterized in that it is made by bundling a large number of tubes having microscopic communication holes and integrating them into a lotus root shape. 6) The liquid filter according to claim 1 has a communication hole having a diameter 1a or a maximum side length d of 10 to 50.
A liquid filter characterized in that the diameter is μm and the number of communication holes per 1 mm is 20 to 800. 4) A liquid filter characterized in that the liquid filter according to claim 1 is made of glass or ceramic.