JPH041051A - Ink-jet recording device - Google Patents

Abstract

PURPOSE:To make a beam member displaced by thermal energy of an exothermic body without allowing said body to make contact with recording liquid by providing the exothermic body to the beam member separately from the recording liquid, and by making the beam member bend by thermal energy of the exothermic body. CONSTITUTION:A cantilever deforms suddenly from its stationary state to a state of displacement in the direction marked with an arrow by bending moment produced by expansion that is brought about by supplying of electricity to a heater 7 of a cantilever-supporting member 10. The movement of the cantilever at this time make ink inside an ink chamber 8 be ejected in the form of ink drops 12 through nozzles of a nozzle plate 11, and recording is made therewith on recording paper. In the above-mentioned process, bending by effect of thermal stress is utilized by heating (by giving thermal shock) only the surface of the cantilever that is made in a single-layer structure. It is necessary to provide the device with better radiation characteristics for improvement of recording frequency. Therefore, it is desirable to arranged the heater 7 in a liquid chamber containing insulating cooling liquid that is provided separately from the liquid chamber 8, or to make the heater 7 to be air-cooled with a fan or the like. In the case where the structure is such that the beam is supported at the opposite ends, the two heaters 7 are arranged on the supporting members on the opposite ends.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an inkjet recording device, and is applied to, for example, printers, plotters, copying machines, and the like.

Prior art related to the present invention includes Japanese Patent Publication No. 60-8953 and Japanese Patent Application Laid-Open No. 62-94347. Tokuko Showa 6
No. 0-8953 discloses a method in which a piezoelectric transducer supported on one side or both sides is disposed in a liquid, and liquid droplets are ejected from a nozzle by bending vibration of the piezoelectric transducer.
No. 2-94347 uses kinetic energy due to bending of a cantilever beam (two-layer structure) heater and generation of bubbles due to heating of the heater to cause droplets to be ejected from a nozzle due to the synergistic effect of the volume displacement.

However, the one published in Japanese Patent Publication No. 60-8953 is 1
It has the following drawbacks: That is, (1) it is necessary to use non-conductive ink. Generally non-conductive ink (oil-based ink)
Because solvents are used, the adhesive deteriorates and the image on the recording paper tends to smudge or blur. ■Using conductive ink requires insulation treatment, which impairs standing properties and increases costs. The 2-layer structure (a combination of a piezoelectric transducer and metal) requires a bonding process, which impairs assemblage and causes variations in vibration displacement. ■A cutting process between the piezoelectric transducer and the metal is required, and variations in the assembly process are likely to occur, making it difficult to expect an improvement in the degree of integration.

Also, the one published in Japanese Patent Application Laid-Open No. 62-94347.

It has the following drawbacks: That is, (1) it requires a protective film because it works in a liquid (there is also a part of the heater in the liquid); ■Special consideration is required in ink design because the ink heats up. ■Since the beam portion is heated, an anti-cavitation layer, such as that known from so-called bubble jets, is required, and the manufacturing process is complicated. ■It has at least a two-layer structure of metal and oxide film, making the manufacturing process complicated.

In addition, there is Japanese Patent Application No. 1-42512, which was filed earlier, but this is because the angle of the beam member is deviated from parallel when the nozzle and the beam member are bent and eject ink.
Ink ejection efficiency is poor.

■--Momme The present invention was made to solve the above-mentioned drawbacks, and by displacing the beam member by the thermal energy of a heating element, or by utilizing electromagnetic wave energy without providing a heating element. This was done for the purpose of providing an inkjet recording apparatus with a simplified recording head configuration.

In order to achieve the above object, the present invention comprises (1) a nozzle, and a beam member that faces the nozzle in close proximity, is disposed in the recording liquid, and has at least one end supported. In an inkjet recording apparatus that records by ejecting recording liquid droplets from a nozzle by bending the beam member, a heating element is provided at the support portion of the beam member, separate from the recording liquid, and the thermal energy of the heating element is used to generate the recording liquid. bending the beam member; or (2) comprising a nozzle and a beam member that faces the nozzle in close proximity and is disposed in the recording liquid and has at least one end supported; In an inkjet recording apparatus that performs recording by ejecting recording droplets from a nozzle through motion, at least a portion of a support portion of the beam member absorbs electromagnetic wave energy to cause the beam member to perform a bending motion.

(3) The beam member is made of a single layer, and further, (4
) The beam member is made of Si or SiC2, or (
5) Consisting of a nozzle and a beam member that faces the nozzle in close proximity and is disposed in the recording liquid and has at least one end supported, recording is performed by ejecting recording droplets from the nozzle by bending the beam member. In the inkjet recording apparatus, a portion of the beam member that faces the nozzle when bent is arranged approximately parallel to the nozzle component, and further, (6) the beam member is in a stationary state and the nozzle component is disposed substantially parallel to the nozzle component. (7) the beam member is placed parallel to the nozzle component in a stationary state, and when the beam member is bent, the nozzle The feature is that the portion facing the is tapered. Hereinafter, the present invention will be explained based on examples.

First, an example of a method for manufacturing a beam necessary for the present invention will be explained with reference to FIGS. 3 and 4. Figure 3 shows the manufacturing method for a cantilever beam, and Figure 4 shows the manufacturing method for a double-sided beam.
Wafer, 2 is Si09 layer, 3 is heater position, 4 is 5
102 is a cantilever beam, 5 is a cavity, and 6 is a double-sided beam made of Si.

In the case of a cantilever beam, a (100) Si wafer 1 is
, layer 2 is formed to have a layer structure as shown in FIG. 3(a), and S
In, layer 2 is patterned as shown in FIG. 3(b). After that, when FDP or KOH is used as an etchant, the cross section obtained by anisotropic etching is shown in Fig. 3(c).
A cantilever beam 4 consisting of iC2 is fabricated.

In the case of a double-supported beam, Si
, layer 2 is formed to have a layer structure as shown in FIG. 4(a), and S
In, layer 2 is patterned as shown in FIG. 4(b). Anisotropic etching is applied to this, and after machining the double-supported beam, the
When the second layer 2 is removed using HF etc., S shown in FIG. 4(c) is formed.
A double support beam 6 of i is manufactured. Figure 4(d) is the same as Figure 4(d).
It is AA' sectional view of C). As shown in these examples, single-layer cantilevered or double-sided beams made of Si or SiO2 can be obtained relatively easily by anisotropic etching of Si and are manufactured using photolithography technology, so the processing accuracy is extremely high. good for

FIGS. 1(a) and 1(b) are configuration diagrams for explaining one embodiment of an inkjet recording apparatus according to the present invention. FIGS. shows the configuration of the recording head in the case of a double-supported beam. In the figure, 7 is a heater, 8 is an ink chamber, 9 is an upper plate (Sl), 10 is a cantilever part, 11 is a nozzle plate (Si), 12 is an ink droplet, 13 is a double support part (Si), 14 is a spacer (Si).

(1) In the case of a cantilever beam FIG. 1(a) shows the configuration of a recording head using a cantilever beam manufactured as shown in FIG. It is preferable that the upper plate a is formed by anisotropic etching of Si as in FIG. 3, and that the nozzle plate 11 is also formed of Si and that the nozzle is formed by etching. It is preferable that the heater 7 is formed at the position indicated by 3 in FIG. 3(b) by a well-known heater manufacturing method for thermal heads, bubble jets, etc. before the cantilever manufacturing method shown in FIG. However, the upper plate (Si)
It is also possible to connect the heater 7 to the cantilever section 10 after forming the heater 7 on the section a. At this time, the heater 7 does not come into direct contact with the liquid, so there is no problem of kogation, which is a problem with bubble jets, for example, and there is no need for an anti-cavitation layer.

Further, a wear-resistant layer is essential in a thermal head used for melting or sublimation type thermal transfer recording, but this method does not require it. In this way, the configuration of the heater becomes very simple. By energizing the heater 7 of the cantilever support part 10, the beam changes rapidly from the static state (2) shown in FIG. 1(a) to the displaced state (2) in the direction of the arrow due to the bending moment generated as the beam expands. Due to the movement of the beam at this time, the ink in the ink liquid chamber 8 is more ink than the nozzle of the nozzle plate 11. 1112 is ejected and recorded onto the recording paper.

Conventionally, such beam structures have been made using a bimetal structure or a bimorph using a piezoelectric element, which uses bending based on the difference in expansion rate or strain between the two glabellar spaces, but here,
Although it is a single layer, only the surface layer is heated (thermal shock), which makes it possible to bend using thermal stress.

The frequency response of the cantilever section is determined not only by the fluid resistance determined by the dimensions and speed of the beam section, but also by the heat transfer characteristics around a portion of the heater. Therefore, in order to improve the recording frequency, it is necessary to improve the heat dissipation characteristics.
It is preferable that the ink liquid chamber 8 be placed in a liquid chamber containing an insulating cooling liquid that is separate from the ink liquid chamber 8, or that it be air-cooled by a fan or the like. Furthermore, by configuring the heating section with a Peltier element.

Rapid cooling after heating is possible, and the frequency of droplet ejection is significantly improved.

(2) In the case of a double-supported beam FIG. 1(b) shows the configuration of a recording head using a double-supported beam manufactured as shown in FIG. The operating principle is the same as that shown in FIG. 1(a), but heaters 7 are arranged at the support portions at both ends of the support beam.

FIG. 2 shows another embodiment of the present invention, in which 1
5 is the upper plate (glass), 16 is the cantilever part (Si+5iOz
), 17 is a semiconductor laser 18 is a coupling lens,
19 is an objective lens. A nozzle plate 11 processed into a nozzle using a cantilever beam and Si anisotropic etching shown in FIG. 3, and an upper plate 1 made of glass with a recess provided therein.
It consists of 5.

The semiconductor laser beam is focused on the cantilever support by a coupling lens 18 and an objective lens 19. At this time,
For the upper plate 15 to prevent the heating efficiency of the laser beam from decreasing, it is preferable to use glass that absorbs little laser light.The movement of the beam member and the ejection of ink droplets due to the heating of the laser beam are as described above. In order to enable the use of a semiconductor laser with a low optical output, it is better to provide an absorption layer having an absorption spectrum at the wavelength of the laser light in the laser irradiation section. For this reason, it is preferable to provide an absorbing layer on the beam portion or the upper plate. In this embodiment, there is no need to provide a heating element, and the configuration of the recording head is significantly simplified.

Next, based on FIGS. 5 and 6 (a) and (b).

Still other embodiments of the present invention will be described. In the figure, 2
0 is a heater, 21 is a greenhouse, 22 is a recording liquid, 23 is a beam member, 24 is an upper plate, 25 is a lower plate, 26 is a nozzle plate,
27 is a nozzle, and 28 is an ink droplet.

According to FIG. 6(a), the beam member 23 and the nozzle plate 2
6 is parallel. The beam member 23 is turned on by energizing the heater.
The dotted line shows the position where the curved and stopped position. ■, ■, ■ indicate the direction of flow of the recording liquid during bending. In order to eject the recording liquid efficiently by bending, the resistance of the fluid between (1), (2), and (2) becomes a problem. In the figure, since the upper part of the nozzle when bent forms an angle θ with the nozzle plate, the fluid resistance in the direction (2) is high, the recording liquid tends to flow in the (2) direction, and the flow (3) in the nozzle direction is blocked, resulting in poor ejection efficiency.

According to FIG. 6(b), the beam member 23 is bent so that the beam member 20 and the nozzle plate 26 are substantially parallel when bent. At this time, if the distance d between the beam member 23 and the nozzle plate 26 and the nozzle diameter r are set in an appropriate relationship, the fluid resistances in the directions ■, ■, and ■ become approximately equal, and the recording liquid It can be seen that the discharge efficiency has improved.

Specific examples are shown in FIGS. 7 and 8. In FIG. 7, the beam member is arranged in advance to face the nozzle plate at an angle θ so as to be substantially parallel to the nozzle plate when bent. The effect upon bending is the same as in FIG. 6(b).

In FIG. 8, the beam member is arranged parallel to and opposite the nozzle plate when it is stationary. However, the tip of the beam member is tapered so that the portion of the beam member facing the nozzle becomes parallel to the nozzle plate when bent.

As is clear from the above description, according to the present invention, the beam member can be displaced by the thermal energy of the heating element without coming into contact with liquid. Furthermore, the configuration of the heating element becomes simple.

Furthermore, there is no need to provide a heating element, and the recording head configuration is simplified.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a recording head for explaining an embodiment of an inkjet recording apparatus according to the present invention.
a) is a case of a cantilever beam, FIG. 1(b) is a diagram showing a case of a double-sided beam, FIG. 2 is a diagram showing another embodiment, and FIGS. 3(a)-
(C) is a diagram showing the method for manufacturing a cantilever beam, Figure 4 (, ) ~
(d) is a diagram showing the manufacturing method of the double-supported beam, Figures 5 and 6.
The figures are 1 diagrams for explaining still another embodiment of the present invention,
FIGS. 7 and 8 are diagrams showing specific examples thereof. 1...Si wafer 2...5i01 layer, 4...
Cantilever beam, 5...Cavity, 6...Both support beam, 7...Heater, 8...Ink liquid chamber, 9...Top plate, 1o...
Cantilevered beam portion, 11... Nozzle plate, 12... Ink droplet, 13... Both supported beam portion. 14...Spacer. Ivy 1 Figure + (]) Ku b) Straw 2 Figure Figure Figure (a) (b) Hane Figure

Claims (1)

[Scope of Claims] 1. Consisting of a nozzle and a beam member that faces the nozzle in close proximity and is disposed in the recording liquid and has at least one end supported, the bending movement of the beam member causes recording liquid droplets to be generated. In an inkjet recording device that records by ejecting it from a nozzle,
a heating element is provided on the support portion of the beam member, separated from the recording liquid;
An inkjet recording apparatus characterized in that the beam member is caused to bend by the thermal energy of the heating element. 2. Consisting of a nozzle and a beam member that faces the nozzle in close proximity and is disposed in the recording liquid and has at least one end supported, recording droplets are ejected from the nozzle by bending movement of the beam member. In an inkjet recording device that records,
An inkjet recording apparatus characterized in that the beam member is caused to bend by absorbing electromagnetic wave energy in at least a portion of a support portion of the beam member.