JPS6338307B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a recording device, and more particularly to a droplet forming device that takes measures to prevent clogging of droplet ejection ports.

Such droplet forming devices are widely used in the field of inkjet recording, and based on the principle of droplet formation, they can be roughly divided into electric field application methods, mechanical vibration methods, and liquid heating methods. . Conventionally, in any droplet forming device that uses any of the methods, there is a possibility that the ejection port will become clogged (because the ejection port is originally minute) and the device will be unable to eject droplets. It's becoming a big problem.

For example, JP-A-54-1, which adopted a liquid heating method,
The device described in Japanese Patent No. 51837 requires various measures for not only heating but also cooling in order to speed up the response speed of droplet ejection flight.
Perhaps for this reason, solidified impurities are likely to occur in the recording liquid in the apparatus, and these impurities stick to the ejection ports, causing problems such as clogging. For this reason, it is necessary to develop a recording medium liquid that does not dry too quickly until it is ejected, but dries quickly after the ejected droplets adhere to the recording paper. are also appearing.

An object of the present invention is to improve the device and eliminate such clogging of the discharge port.

Furthermore, in inkjet recording heads that use solid sublimable dyes as the recording medium, even if the sublimable dyes sublimate in the range of 200 to 600°C, the recording head will deteriorate when it is subsequently cooled by the outside temperature. This is disadvantageous because recrystallization (of the sublimable dye) occurs inside and outside, causing clogging. The present invention can also eliminate such clogging factors.
That is the purpose.

Accordingly, the present invention that achieves the above object provides a recording medium supply path including a storage tank for storing a recording medium made of or containing a sublimable dye, and a record medium supplied through the supply path. means for generating energy used to eject the medium and make it adhere to the recording medium; and the sublimable dye used to prevent the sublimable dye from adhering to the inner wall surface of the supply path. A recording apparatus characterized by having a heating means for generating thermal energy up to a sublimation temperature or a decomposition temperature.

That is, in the present invention, a heating section is provided around the recording head in order to prevent the recording liquid from solidifying and sticking to the inside and outside of the recording head and clogging the ejection ports. Usually, a heating section is provided along the liquid chamber of the recording head section. In some cases, the heating portion is formed very close to the orifice.

The present invention will be described in detail below while comparing embodiments of the present invention and conventional examples.

First, an example of recording liquid discharge recording using a liquid heating method will be described with reference to FIG. 1 showing its basic principle. In the liquid chamber 1, a pressure P is applied to the recording liquid 3 by an appropriate pressurizing means such as a pump to the extent that it cannot be discharged from the orifice 2 by itself.
is supplied.

Now, when the recording liquid 3 in the liquid chamber 1 at a distance l from the orifice 2 is subjected to thermal energy by the heating element 5, the liquid expands or bubbles are generated due to a sudden change in the state of the recording liquid 3. Depending on the amount of energy applied, a part or all of the recording liquid 3 existing within the width l of the liquid chamber 1 is ejected from the orifice 2 and flies in the direction of the recording member 4.
Adhere in place on top.

In this case, first, the recording medium liquid 3 is introduced into the liquid chamber 1 by an appropriate pressurizing means such as a pump until the recording liquid 3 in the liquid chamber 1 is affected by thermal energy and is discharged from the orifice 2. Even if it is in the introduction part and the liquid chamber 1, it is recorded on the side wall up to the installation part of the heating element 5 for discharge, the inner wall from the heating element 5 to the discharge orifice 2, and the outer wall of the orifice 2, etc. Adhesion of liquid 3 is considered. It is fine if this is just adhesion, but if it adheres, the orifice 2 will be blocked and the recording liquid 3 will no longer be ejected from the orifice 2.

In addition, this clogging can also be caused by changing the diameter of the discharge orifice, which inhibits the formation of homogeneous droplets.

Furthermore, in the case of a recording device in which the recording liquid 3 is composed of a sublimable dye, the dye heated to the sublimation temperature by the heating element 5 causes a state change from a solid to a gas instantaneously, but the liquid chamber 1 It is cooled at a location farther from the internal heating element 5, for example, near the dye inlet or the tip of the orifice 2, and recrystallization progresses, causing dye crystals to adhere.

Therefore, it is necessary to devise a method to prevent recrystallization of the dye. Here, a more specific explanation will be given with reference to the embodiment shown in FIG.

In FIG. 2, heating means 6a and 6b are provided along the outer wall of the liquid chamber 1 to increase the temperature of the recording medium 3 inside the liquid chamber 1. The heating means 6b is provided near the orifice 2 separately from the heating element 5 for ejecting the recording medium.

Here, the heating means 6a and 6b are resistance wires such as nichrome wires and heater wires, or any heat generating member that absorbs the energy of the laser light and generates heat when laser light is introduced from the outside through a suitable optical system. Electrical energy of 100 watts to 500 watts is applied to the resistance wire to raise the temperature of the recording medium 3 to 100°C.
The temperature can be set to ~600℃. The set temperature is set to a temperature that achieves the purpose of preventing the recording medium 3 or recording medium liquid droplets from adhering to the inside and outside of the liquid chamber 1, but it specifically depends on the type of recording medium used. and are set at various temperatures.

For example, as a recording medium, the active ingredient is Cu-
In the case of phthalocyanine, the sublimation temperature of Cu-phthalocyanine is in the range of 500 to 600°C. In the case of Cu-phthalocyanine with a purity of 99.99%, the sublimation temperature was 540°C, so the heating temperature by resistance wire heating was set at 450°C to 500°C.

Furthermore, in the case of Rhodamine G, the sublimation temperature is
Since the temperature was 350°C, the heating section temperature was set at 300 to 350°C.

The dyes in the above embodiments are both blue and red dyes to form blue and red recording media. In the case of other dyes, a temperature up to the sublimation temperature or dye decomposition temperature is similarly applied by the heating means 6a, 6b. In particular, when a solid sublimable dye is used as the recording medium 3, it instantly turns into a gas when it reaches the sublimation temperature, so between gases,
No clogging occurs. Further, at temperatures below the sublimation temperature, the dye is in a state where it is extremely easy to be liberated on the wall surface of the liquid chamber, and is in a state where it is immediately blown away by an air current. In other words,
Sublimable dyes generally have a powdery, granular shape as a solid, but immediately before sublimation, they become a filament-like solid.

In the embodiment shown in FIG.
(The specific configuration is the same as that shown in FIG. 2), recording medium storage tanks 8, 9,
Cyan, magenta, and yellow recording media 3 are stored in the recording media storage tanks 8, 9, and 10, respectively, and introduction pipes 12-1, 12-2, and 12- There is a device configured such that 3 is connected. This introduction pipe 12-1,
A heating means 13 is provided for the purpose of preventing the recording liquid or the recording medium 3 from adhering to the recording heads 12-2 and 12-3.

In the case of this embodiment, a heating element 11 is attached to each color recording medium storage tank 8, 9, 10, and an inlet pipe from the storage tank 8, 9, 10 to the recording head 7. 12-1, 12-2, 1
This has the effect of vaporizing the recording medium within 2-3.

Further, when a sublimable dye is stored in the recording medium storage tanks 8, 9, and 10 and is vaporized by the heating element 11, the heating means 13 is set to approximately the sublimation temperature of the dye. By doing so, it is possible to prevent the recording medium from adhering to the wall surface of each introduction tube.

In particular, as shown in Figure 3, when recording using sublimable dyes, recording media of three colors, cyan, magenta, and yellow, or four colors, including black, are placed on the head 7.
The recording medium is ejected from the ejection opening 7a of the recording head 7 in accordance with a series of image signals.

FIG. 4 describes an embodiment in which a recording medium liquid 24 is ejected from an orifice 23 of a recording head 21 in response to a pressure signal from a piezoelectric element 22 made of a piezo.

In the recording head 21 as shown in FIG.
is provided to heat the recording medium liquid 24 and the recording head wall surface. In particular, when a sublimable dye is used as the recording medium 24 in such a recording head, the head 21
A dye supply hole 25 is provided at the bottom of the recording head, through which the sublimable dye is introduced while being vaporized.Furthermore, by setting the temperature of the heating means 26 to the sublimation temperature, the wall surface of the recording head can be coated with metal (branch). Yu, iron,
(nickel, aluminum, etc.), it is possible to make the temperature almost the same as that of the heating means 26,
This prevents the recording medium 24 from solidifying until it is ejected. As a result, droplets 27 of uniform diameter can be formed. Note that 28 indicates a piezoelectric element driving section.

In the present invention described above, solidification of the recording medium on the inner wall surface of the recording head liquid chamber is prevented.

Since the recording medium does not stick to the vicinity of the orifice of the recording head, clogging does not occur.

When the recording medium undergoes a state change due to heating, the resulting pressure can prevent the recording medium from adhering to parts other than the heating element in the recording system.

Even when the distance between the storage tank or the liquid chamber and the orifice is long, the recording medium is prevented from adhering to the wall surface of the conduit, thereby preventing clogging in the pipe.

It can be sufficiently driven using a sublimable dye.

Effects such as these can be listed.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view illustrating a conventional example of a droplet forming device, and FIGS. 2 to 4 are all
FIG. 1 is a schematic cross-sectional view illustrating an embodiment of the present invention. In the figure, 1 is a liquid chamber, 2, 7a, 23 are discharge ports, 3, 24 are recording media, 5 is a heating element, 6a, 6
b, 13, 26 are heating means, 7, 21 are recording heads, 8, 9, 10 are tanks, 11 is a heating element, 12
-1, 12-2, 12-3 are conduits, and 22 is a piezoelectric element.

Claims (1)

[Claims] 1. A recording medium supply route including a storage tank for storing a recording medium made of or containing a sublimable dye, and a recording medium supplied through the supply route to be discharged and adhered to a recording medium. and thermal energy up to the sublimation temperature or decomposition temperature of the sublimable dye, which is used to prevent the sublimable dye from adhering to the inner wall surface of the supply path. A recording device comprising a heating means for generating.