JPH0733090B2 - Ink recording device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention discharges a small droplet of liquid ink toward a recording sheet,
The present invention relates to an ink recording device that performs recording by flying.

2. Description of the Related Art Conventional ink recording devices are roughly classified into two types. One of them is so-called continous recording, in which minute ink droplets are continuously ejected and jetted, and only the ink droplets required for recording are selected from these ink droplets and guided and adhered onto the recording paper. The other is a so-called on-demand method, in which the ink droplet is ejected toward the surface to be recorded and ejected to perform recording only when necessary for recording.

By the way, one of the ink recording devices for implementing the latter method is disclosed in, for example, Japanese Patent Laid-Open No. 54-51837. FIG. 4 shows the configuration of this conventional ink jet recording apparatus, in which 21 is ink, 22 is an ink ejection port for ejecting the ink 21, 23 is an ink supply port for supplying the ink 21, 24 is an ink liquid chamber, Reference numeral 25 is a heating element provided on the ink liquid chamber 24, and 26 is a bubble generated by heating the ink 21 by the heating element 25.

In the conventional ink recording apparatus configured as described above, the liquid ink 21 in the ink liquid chamber 24 supplied from the ink supply port 23 is heated by the heating element 25 to form bubbles 26 in the ink liquid chamber 24. The ink 21 is generated and the ink 21 is ejected from the ink ejection port 22 due to the pressure increase due to the increase in volume, and the ink 21 is ejected for recording.

Problems to be Solved by the Invention However, the above-mentioned configuration has the following problems. That is, when the ink is ejected from a film or a lump, that is, when the ink is divided into fine droplets and fly, it is necessary to give shearing energy to the ink in addition to the energy for flying, which prevents an increase in recording sensitivity. ing. In addition, the size of the small droplets that are created when the ink is divided is
It is greatly affected by the pressurizing condition and the physical properties of the ink at the time of division, and the recording dot diameter becomes non-uniform, which becomes an unstable factor of recording and printing quality. Further, since the ink is always present in the vicinity of the ejection port, clogging of the ejection port due to drying of the ink when recording is not performed deteriorates the recording and printing quality.

In view of the above points, the present invention has an object to provide an ink recording apparatus in which recording characteristics such as recording sensitivity and print quality are improved by forming ink in a particle shape immediately before ejection.

Means for Solving the Problems The present invention includes an ink chamber having an ink therein, an ink supply port, and an ink ejection port for ejecting ink supplied from the ink supply port. The ink recording apparatus is characterized in that the contact angle between the inner wall surface and the ink is 90 degrees or more.

Action The present invention has the above-described configuration, and the ink is formed into particles before being ejected. That is, the ink supplied into the ink chamber before the pressure is applied to the ink naturally becomes particulate because the contact angle at the interface between the ink and the ink chamber is 90 degrees or more.
If pressure is applied to the ink at that stage, the ink is ejected in the form of particles. Therefore, when the ink is separated from the ink chamber, the contact area between the ink and the ink chamber is very small and there is no contact with other inks, so that the energy required for the division is almost unnecessary, and only the energy for flight should be given.

In addition, the size of the granular ink is determined by the conditions of the ink supply and the ink chamber, and is not related to the pressurizing condition at the time of recording or the characteristics that are easily affected by the environment and changes over time, such as the ink dividing condition, so it is stable. The obtained recording characteristics can be obtained. Since the ink is supplied to the vicinity of the ink ejection port immediately before recording, the ink is not exposed to the outside air when recording is not performed, and clogging due to drying does not occur.

Embodiment 1 FIG. 1 is a sectional structural view of an ink recording apparatus according to a first embodiment of the present invention. In FIG. 1, 1 is ink, 2 is pressurized liquid, 3 is ink ejection port, 4 is ink supply port, 5 is ink chamber, 6 is pressure chamber, 7 is ink chamber 5 and pressure chamber 6. A pressing plate, 8 is a diaphragm. Pressure plate 7
Is provided at the boundary between the ink chamber 5 and the pressure chamber 6, is in contact with the pressure liquid 2, and faces the ink ejection port 3. Ink 1
Is an ink having a relatively high viscosity containing a coloring material. Diaphragm 8
Is provided on the wall of the pressure chamber 6 so as to face the pressure plate 7.
The diaphragm 8 is, for example, a piezoelectric ceramic, and the pressure plate 7 is, for example, a metal diaphragm. The material and the surface shape of the inner wall of the ink chamber 5 and the ink 1 are configured so that the contact angle between the inner wall surface of the ink chamber 5 and the ink 1 is larger than 90 degrees. Formed into a shape.

The contact angle means the ink 1 and the wall surface 11 as shown in FIG.
The angle θ between the tangent line of the ink 1 and the wall surface 11 at the contact point A with

Ink 1 is chemically and physically stable similarly to the ink used in the conventional recording method, and has properties such as sufficient recording density and good storage life. Physical properties are adjusted. The composition of Ink 1 is a coloring material, a solvent, and an additive. When a water-based ink is used as the ink 1, the solvent is water or water / alcohol. When the solvent is water, for example, the contact angle for water is 10
A layer of solid paraffin of 8 degrees, polypropylene of 101 degrees, polytetrafluoroethylene of 108 degrees or the like is provided on the inner wall of the ink chamber 5.

The operation of the ink recording apparatus of this embodiment constructed as above will be described below. FIG. 1A shows a state in which no voltage is applied to the diaphragm 8. In this state, when a voltage of a predetermined value is applied to the diaphragm 8 to eject and record one ink droplet, the piezoelectric Due to the effect, the diaphragm 8 is deformed at a predetermined frequency. The pressurized liquid 2 in contact with the surface of the vibration plate 8 amplifies the vibration and transmits it to the pressure plate 7. When the diaphragm 8 is deformed in the direction of decreasing the volume of the pressurizing chamber 6, the state shown in FIG. 1 (b) is obtained. The pressure plate 7 is deformed in the direction in which the volume of the ink chamber 5 is reduced and applies pressure to the ink 1. As a result, the ink 1 is ejected from the ink ejection port 3 and ejected to record on a recording paper (not shown).
When the voltage application to the diaphragm 8 is stopped, the diaphragm 8 is not deformed and the pressure in the pressurizing chamber 6 is reduced. Therefore, the pressure plate 7
Returns to the original. After that, the ink 1 is supplied to the ink chamber 5, and the state of FIG.

As described above, according to this embodiment, since the ink is formed into particles before being ejected, the energy required for dividing the ink is unnecessary, the size of the granular ink is stable, and the sensitivity and print quality are improved. It is possible to obtain an excellent ink recording device.

FIG. 2 is a sectional structural view of an ink recording apparatus according to the second embodiment of the present invention. A heating element 9 is fixed to the bottom surface of the pressurizing chamber 12. Here, the ink 1 and the pressurized liquid 2
Have physical properties that are immiscible with each other, such as aqueous and oily. The immiscibility means that the mixed state does not become a mixed state even if it is stirred, but becomes a dispersed state due to a difference in polarity, specific gravity and the like. Here, for example, the ink 1 uses water or a water / alcohol system as a solvent. The pressurized liquid 2 is an oily material having a low boiling point and a low viscosity, such as toluene, benzene, and hexane.

In this embodiment, the operation is almost the same as that of the first embodiment, but the bubble 10 generated by the heating of the heating element 9 which is the heat energy supply means from the state of FIG.
The internal pressure of 12 is increased, and as shown in FIG. 2 (b), the pressurized liquid 2 ejects and ejects the ink 1 from the ink ejection port 3 to perform recording on recording paper (not shown).

When the application of the voltage to the heating element 9 is stopped, the bubbles 10 are rapidly cooled and returned to the liquid, thereby contracting, and the pressurized liquid 2 becomes the heating element.
Returning to the 10 side, the state shown in FIG. Since the ink 1 and the pressurized liquid 2 are immiscible, they are completely separated from each other at the interface between the ink 1 and the pressurized liquid 2. The ink 1 is pushed out of the ink supply port 4 into the ink chamber 5 by an ink supply member (not shown). In this embodiment, the ink supply member is driven immediately before the voltage is applied to the heating element 9 for recording. To supply ink. Therefore, the ink 1 is pressurized in response to the supply of the ink 1.

When recording is not performed, the ink 1 is not pushed out into the ink chamber 5. Since the ink 1 is repelled by the inner wall surface of the ink chamber 5, while the force for pushing out the ink 1 by the ink supply member is not applied, the ink 1 enters the ink chamber 5 due to a capillary phenomenon or the like.
Never intrudes. Therefore, the state shown in FIG. 2C and the state shown in FIG. 2A are only immediately before the ejection of the ink 1. Therefore, it is possible to prevent the ink ejection port 3 from being clogged due to the drying of the ink 1 containing the coloring material.

In this embodiment, since the pressure change of the pressurizing liquid 2 is transmitted to the ink 1 as it is, there is no energy loss, and recording with higher sensitivity than in the first embodiment is possible. Therefore, according to this embodiment, it is possible to obtain an ink recording apparatus capable of recording with higher sensitivity and higher print quality. It was possible to record the ink 1 on a recording sheet by applying a pulsed recording voltage to the heating element 9 of the recording apparatus of this example. The energy required for recording is about 0.06 J / cm ² , there is no clogging at the ink ejection port of the ink 1, and no deposit is generated on the surface of the heating element 9 even when recording is repeated. Although the ink is water-based in this embodiment, it may be oil-based. In that case, it is necessary to optimally set the material composition of the ink chamber inner wall and the pressurized liquid for the oil-based ink.

Further, in these embodiments, the ink chamber and the pressurizing chamber are separated, but the pressurizing chamber may not be provided. In that case, the pressure is directly applied to the ink by some pressure means.

As described above, according to these embodiments, it is possible to obtain an ink recording apparatus with improved characteristics such as recording sensitivity and print quality.

In the second embodiment, the case where the heating element is used as the heat energy supplying means has been described as an example, but the pressurized liquid may be heated by laser light, light from the light emitting diode array, or the like. Further, in the present embodiment, the case where the bubble generation is used as the means for generating the pressure in the pressurized liquid by the thermal energy supply means is shown, but other state changes such as thermal expansion of the pressurized liquid may be used. Good. When the pressurized liquid is not used, thermal expansion of ink may be used. In this case, as the pressurized liquid or the ink, for example, a low-viscosity liquid having a high thermal expansion coefficient is used to improve the recording sensitivity.

The heating element 9 may be held in the pressurized liquid 2 without being fixed to the pressure chamber.

EFFECTS OF THE INVENTION As described above, according to the present invention, there is provided an ink recording apparatus in which characteristics such as recording sensitivity and print quality are improved by forming ink in a particle shape in the vicinity of an ink ejection port immediately before ejection recording. It is possible and its practical effect is great.

[Brief description of drawings]

FIG. 1 is a sectional structural view of an ink recording apparatus according to a first embodiment of the present invention, FIG. 2 is a sectional structural view of an ink recording apparatus according to another embodiment of the present invention, and FIG. 3 explains a contact angle. FIG. 4 is a cross-sectional structural view of a conventional ink recording device. 1 ... Ink, 2 ... Pressurized liquid, 3 ... Ink ejection port, 4
…… Ink supply port, 5 …… Ink chamber, 6,12 …… Pressurization chamber,
7 ... Pressure plate, 8 ... Vibration plate.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical display location B41J 3/04 102 Z (72) Inventor Takahiko Nanko 1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric Industrial Co., Ltd. In-house (56) References JP 59-26270 (JP, A) JP 63-22660 (JP, A) JP 63-17622 (JP, B2) JP 58-30834 (JP, B2) )

Claims (2)

[Claims] 1. An ink chamber having ink therein, having an ink supply port and an ink ejection port for ejecting ink supplied from the ink supply port, the inner wall surface of the ink chamber and the ink. An ink recording apparatus having a contact angle of 90 degrees or more. 2. The ink recording apparatus according to claim 1, wherein the ink is filled from the ink supply port into the ink chamber immediately before the pressure is applied to the ink.