JPS6364751A - Recording head for inkjet printers - Google Patents

Abstract

PURPOSE:To simplify a means to recover a deterioration of printing quality due to clogging or bubble entrainment by providing a device to pressurize an ink tank inside the ink tank. CONSTITUTION:A lever 41 is provided on an opposite side to an orifice 15 of a nozzle pipe 11 in an ink tank 20. The lever 41 operates in arrow P and Q directions through the side wall of the ink tank 20 and a packing 42. A valve 43 is positioned downward under its own weight when an ink is ejected, and has an open aperture 44 which prevents the pressure inside the ink tank 20 from dropping. When a purge cycle has set in, the valve 43 closes the aperture 44 by pressure, and the pressure in the ink tank 20 increases, if the lever 41 is pressed in the arrow P direction. As a result, the ink is discharged from the orifice 15, thus removing foreign matter attaching to the orifice 15 and high-viscosity ink and bubbles in the nozzle pipe 11. If the purge cycle ends, the valve 43 operates downward under its own weight and the aperture 44 opens. Consequently printing is automatically commenced.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a recording head for an inkjet printer,
In particular, the present invention relates to a recording head for an inkjet printer that is suitable for recovering from deterioration in printing quality due to clogging of ink ejection ports and entry of air bubbles.

[Conventional technology]

An on-demand inkjet recording device changes the volume of an ink chamber in a nozzle head using an information signal, and ejects ink particles from a nozzle hole to reproduce information on a recording medium. A special ink pressurizing mechanism is not required to eject ink particles, and a printer with a simple structure can be realized.

A conventional device, as described in Japanese Patent Application Laid-Open No. 58-194567, includes a holder for sealing the tip of the nozzle, a device for advancing the holder toward the nozzle, a negative pressure suction device, and a device for connecting them. It consists of tubes, etc.

Therefore, conventional recording heads for inkjet printers are shown in FIGS. 4@2, 3, and 4.

FIG. 2 is a schematic diagram of the configuration of the printer, in which a nozzle head 1 is fixed to a carrier plate 2 with a stopper 3. The carrier base 2 is movable on rails 4 and 5 in the left and right directions A and B with respect to the recording medium 7. Ink particles 6 are ejected from the nozzle head 1 and record an image 8 on a recording medium 7 that is transported in the direction of arrow C.

FIG. 3 is a configuration diagram of a conventional nozzle head, in which a nozzle 10 includes a nozzle pipe 11, an electromechanical transducer element such as a piezoelectric element 12. It consists of a tube 13 and a filter 14, and a fine orifice 15 is formed at the tip of the nozzle pipe 11.

The piezoelectric element 12 has a cylindrical shape and is fixed to the nozzle pipe 11, and an information signal 9 is applied to it via a conductive wire 16 and an electrode 17.

Place the ink tank 20 into the orifice 1 of the nozzle pipe 11.
The nozzle pipe 11 is filled with ink 21 and is supplied to the nozzle pipe 11 through the filter 14 and tube 13.

In FIG. 3, when an information signal 9 is applied to the piezoelectric element 12 of the nozzle 10, the volume of the nozzle pipe 11 contracts and ink particles 6 are ejected.

FIG. 4 is a diagram illustrating the operation of a device (hereinafter referred to as purge) that removes foreign matter, bubbles, etc. when they occur in the orifice 15, showing the main parts of the nozzle head 1, and FIG. Components that are the same as those in FIG. 3 are given the same numbers, and explanations will be omitted.

30 is a purge mechanism section, and a cap 31 is a nozzle head 1.
When the valve 36 in the suction pump chamber 35 is lowered in the direction of the arrow, the suction pump chamber 35 and the concave portion a of the nozzle head 1 are covered.
becomes a negative pressure, and the nozzle pipe 11. The ink 21 is sucked through the tube 13 and the filter 14, and
It is possible to remove foreign matter adhering to the nozzle pipe 5, high viscosity ink inside the nozzle pipe 11, and air bubbles.

When the purge operation is completed, the cap 31 is removed from the recess a of the nozzle head 1 by a return mechanism (not shown), and the valve 36 in the suction pump chamber 35 returns in the direction of the dotted arrow E.

[Problem that the invention seeks to solve]

In the above-mentioned conventional technology, when foreign matter adheres to the vicinity of the nozzle ejection port and causes clogging, and when air bubbles are generated in the nozzle, the device for removing the foreign matter and bubbles is complicated.

An object of the present invention is to simplify a means for recovering from deterioration in printing quality due to clogging and entry of air bubbles.

Means for Solving Problem C] The above object is to provide an inkjet nozzle formed by fixing a cylindrical electromechanical transducer to a nozzle pipe, a means for supplying ink to the nozzle, and an ink tank for storing the ink. This is achieved by providing a recording head for an inkjet printer comprising a device for pressurizing the ink tank in the ink tank.

[Effect]

When the ink chamber is pressurized, pressure is applied to the ink in the ink chamber, and dust, high viscosity ink, and air bubbles at the tip are forcibly ejected. This makes it possible to eliminate ink non-discharge or deterioration in print quality.

〔Example〕

Hereinafter, one embodiment of the present invention will be explained with reference to FIG. 1.
17H is a sectional view of an ink tank used in a recording head for a jet printer.

The orifice 15 of the nozzle pipe 11 of the ink tank 20
A lever 41 is provided on the opposite side.

The V par 41 connects the side wall of the ink tank 20 and the gasket 42.
It operates in the directions of arrows P and Q through the arrows P and Q.

Reference numeral 43 denotes a valve, whose tip is positioned downward under its own weight when the ink is ejected, and which opens the hole 44 and closes the ink tank 20.
This prevents a drop in internal pressure.

During purge operation, when lever 41 is pushed in the direction of arrow P,
The valve 43 closes the hole 44 due to pressure, and the gas tank 2 is closed.
The pressure within 0 increases. As a result, the ink 22 is pressurized, and the ink is ejected from the orifice 15, and foreign matter adhering to the orifice 15, high viscosity ink in the nozzle pipe 11, and air bubbles can be removed.

Further, the ink ejected from the orifice 15 is received by an ink recovery container (not shown).

When the purge operation is completed, the valve 43 moves downward under its own weight,
Since the hole 44 is open, printing can be started until then.

As described above, by providing a device for removing attached foreign matter, high viscosity ink in the nozzle, and air bubbles in the head, there is no need for special equipment as in conventional printers, and the printer has a simple structure. can be provided.

〔Effect of the invention〕

According to the present invention, it is possible to recover from ink failure due to clogging, air bubbles entering the nozzle, or deterioration in print quality with a simple device.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a nozzle head used in a recording head for an inkjet printer equipped with the present invention, FIG. 2 is a perspective view of a conventional nozzle head, FIG. 3 is a cross-sectional view of a conventional nozzle head, and FIG. The figure is a sectional view of a main part of a conventional nozzle head. 1... Nozzle head, 10... Nozzle, 12...
Piezoelectric agent patent attorney Katsuo Ogawa <-'-:, , 1″
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Claims (1)

[Claims] 1. A recording head for an inkjet printer comprising an inkjet nozzle having a cylindrical electromechanical transducer fixed to a nozzle pipe, means for supplying ink to the nozzle, and an ink tank for storing the ink. A recording head for an inkjet printer, characterized in that the recording head is provided in a device that pressurizes the ink tank inside the tank.