JPS63242644A - Ink jet printer - Google Patents

Abstract

PURPOSE:To prevent ink from drying, by providing a magnetic fluid layer at the tip of a nozzle section with a thickness thinner than a specific dimension. CONSTITUTION:An ink jet printer is provided at the tip of a nozzle section 3 with a magnetic fluid layer 2 of a thickness thinner than 100mum. Ink 5 subjected to pressure through a piezoelectric element 4 passes through magnetic fluid 2 at the nozzle section 3 and flies in the form of a drop. Normally, the magnetic fluid 2 features saturated vapor pressure of 4.5X10<-4>Torr(30 deg.C) and evaporation rate of 3.25X10<-10>g/cm<2>.sec(60 deg.C). Consequently, variation of weight is less than -7% even after five years(30 deg.C). When the magnetic fluid 2 is arranged at the tip of the nozzle section 3 with a thickness thinner than 100mum, ink is not exposed directly to the atmosphere when the printer is not used, thus protecting ink from drying.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to the structure of a nozzle section of an inkjet printer.

[Conventional technology]

A row of nozzle sections in a conventional inkjet printer is shown in FIG. 2. As shown in FIG. 2, the tips of the nozzle sections 3 are covered with caps 6 after use to prevent ink from drying out.

(Problems to be Solved by the Invention) However, with the above-mentioned prior art, there are cases where the ink dries out due to the cap not fitting properly or being forgotten. The present invention is intended to solve these problems, and its purpose is to provide a highly reliable inkjet printer by covering the nozzle portion with a magnetic fluid to prevent the ink from drying out.

[Means for solving problems]

The inkjet printer of the present invention is characterized in that a magnetic fluid layer with a thickness of 1100 J or less is installed at the tip of the nozzle portion.

[Effect]

According to the above configuration of the present invention, the magnetic fluid usually has a saturated vapor pressure of 4.5 X l (I Torr (30°C) and an evaporation rate @
11 @ L25 X LO-10f/cm”, 5
ac (60℃), and from this 5 years later (3
Since the weight change is -7 or less even at 0°C), by installing the ink at the tip of the nozzle part, the ink is not directly exposed to the atmosphere when not in use and can be prevented from drying.

[Implementation row]

Embodiment IAI FIG. 1 is a cross-sectional view of a discharge section in an embodiment of the present invention, and in FIG. Fly as droplets. To explain in more detail with reference to Figure 1 (extension), a permanent magnet l with a tapered tip is placed near the nozzle,
ai sex fluid 2t - inject. At this time, the a-field strength of the permanent magnet is t! ! The physical property of the magnetic fluid is saturation magnetization of 300 Gauss.

The viscosity is 400p8 and the thickness of the m-fluid layer from the nozzle part! is ~(9) μm. The initial speed of am flying from the nozzle of this manufactured inkjet head was 3.1%.
3.2 m/se if there is no 1m fluid layer at /8-C
c, the deceleration that occurs when passing through the injected fluid layer is only a few percent, so it hardly poses a problem in practice.The resulting inkjet printer was placed in a room with a humidity of 10%. I left it alone for a year, and even after that, I was able to print immediately and there was no clogging due to drying of the ink.

Implementation row 2 An inkjet printer similar to implementation row 1 was made and the length was 1 m.
The table shows the results of investigating the relationship between the thickness of the fluid layer and the drying and initial velocity of the ink.

Implementation Row 3 A bubble jet type printer as shown in FIG. 3 was manufactured. The physical property III of the m-injected fluid at this time is the saturation magnetization l-
250G, viscosity mm is 80 cpa, and the thickness of the magnetic fluid layer at the nozzle tip is μm. This bubble jet printer can also be used at room temperature 3 (I:, humidity 10%).
There were no problems for more than 0 days.

〔Effect of the invention〕

As described above, according to the invention, by simply replacing the conventional cap with a magnetic fluid, there is no need to put the cap back on after each use, and there is no need to worry about the cap not fitting properly.

This has the effect that the ink in the nozzle section hardly dries. Furthermore, by using this method, conventionally, after a single ink droplet was ejected, gas from the atmosphere was sucked in, and the gas had an adverse effect on the flow path, making it impossible to eject the ink droplet. When the formula is used, the ink liquid Wk passes through the l@ fluid layer and flies, so there is also the effect that gas is not directly sucked in.

[Brief explanation of the drawing]

FIG. 1-(A) is a main sectional view showing an embodiment of the ejection part of the inkjet printer of the present invention. Fig. 1-Stem) is an enlarged sectional view of Fig. 1-α Fig. 2 is a main sectional view showing the ejection part of a conventional inkjet printer Fig. 3 is a main sectional view of the nozzle part of the bubble jet manufactured in 913 . l@...Permanent magnet 2...Magnetic fluid 3...Nozzle portion 4...Piezoelectric element 5...Ink 6...Cap 7...Nozzle 8...Heating resistance element 9... Bubble and above Applicant Seiko Epson Co., Ltd. agent Patent attorney Sai and Tsutomu and 1 other person (△) 1st r! ! A 21st! ! Third! ! 1

Claims (1)

[Claims] An inkjet printer characterized in that a magnetic fluid layer with a thickness of 100 μm or less is installed at the tip of a nozzle part.