JPH04344250A - Ink discharge device to be used in ink jet printing system - Google Patents

Abstract

PURPOSE:To discharge ink smoothly by responding quickly to a specific in put signal by a method wherein alternate voltage is flashed to an electrode board and an electret film is vibrated to apply vibration to ink passing through an ink chamber. CONSTITUTION:Ink pressurized is supplied to an ink chamber 2 from an ink tank 3 via an ink pressure device 4, and the ink is discharged from a nozzle 1 through an ink passage 5. An electrode board 5 is provided along the ink passage 5 in the ink chamber 5, and a flexible electret film 11 is provided on the ink passage 5 side facing the electrode board 10 by fixing both ends. An AC power source or pulse power source 12 is connected to the electrode board 10. Electric attraction or repulsion alternately acts on the flexible electret film 11 according to alternate voltage to be impressed to the electrode board 10, and the film 11 is vibrated to apply vibration to the ink passing through the passage 5. Therefore, speed of response can be increased for a specific input signal and this phenomenon is extremely effective, for example, for high speed recording.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink discharge device used in an ink jet printing system, and more particularly to an ink discharge device using an electret film.

0002

2. Description of the Related Art An inkjet printing system records ink by ejecting it from a nozzle and spraying it onto paper. That is, in this method, ink pressurized by an ink pressurizing device is guided to a nozzle, and the ink is ejected from the nozzle hole. In this case, the nozzle is provided with a piezoelectric element excited by a high-frequency voltage, so that the nozzle vibrates, and the ink passing through the nozzle also vibrates. Due to the effect of this vibration, the ejected ink flies out as an ink column for a while, but then it continuously separates into uniform particles that have a constant size and fly at a constant speed.

0003

However, nozzles using piezoelectric elements as described above have a drawback of slow response speed. SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an ink ejection device that quickly responds to a certain input signal and can smoothly eject ink from a nozzle.

0004

[Means for Solving the Problems] According to the present invention, the ink chamber includes an ink chamber equipped with a nozzle at its tip, ink is supplied from the ink tank to the ink chamber via an ink pressurizing device, and ink is ejected from the nozzle. In the ink ejecting device used in the inkjet printing system, an electrode plate is provided in the ink chamber along the ink passage, and a flexible electret film has both ends facing the electrode plate and facing the ink passage. An ink ejecting device is provided, characterized in that the ink ejecting device is fixedly provided, and alternate voltages are applied to the electrode plates, the electret film vibrates, and ink is ejected from the nozzle tip.

[0005]

[Function] Electret is a dielectric material that exhibits a permanent electric polarization effect, and a remarkable feature of the present invention is that the electrical properties of this electret are utilized to impart vibrations to the ink passing through the ink chamber. That is, according to the present invention, a flexible electret film is provided facing the electrode plate, and by applying alternating voltages to the electrode plate, electrical attraction and repulsion are alternately applied to the electret film. As a result, the electret film vibrates in accordance with the frequency of the applied alternating voltage, and vibrations are imparted to the ink passing through the ink chamber. According to such a device, vibrations are applied to the ink in immediate response to the applied alternating current voltage.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained in detail below based on specific examples shown in the accompanying drawings. In FIG. 1 showing the main parts of an ink ejecting apparatus of the present invention, this apparatus consists of an ink chamber 2 having a nozzle 1 at its tip. Pressurized ink is supplied to the ink chamber 2 from an ink tank 3 via an ink pressurizing device 4, and the ink is discharged from the nozzle 1 through an ink passage 5.

In the present invention, in the ink chamber 2,
An electrode plate 10 is provided along the ink passage 5, and a flexible electret film 11 is provided on the ink passage 5 side, facing the electrode plate 10, with both ends fixed. Furthermore, the electrode plate 10 is provided with an AC power source or a pulse power source 12.
is connected. In such a device, the electrode plate 10
According to the alternating voltages applied to the flexible electret film 11, electrical attractive and repulsive forces alternately act on the flexible electret film 11, thereby causing the film 11 to vibrate and impart vibrations to the ink passing through the passage 5.

In the present invention, any polymeric material can be used as the material for the electret film 11 as long as it is a film-forming material that can be permanently electrically polarized and has sufficient flexibility to vibrate. It is possible, but
Generally, olefin resins such as polyethylene, polypropylene, ethylene-butene copolymer, ionically crosslinked olefin copolymer, ethylene-acrylic copolymer; polyvinyl fluoride, polyvinylidene fluoride, vinyl fluoride/
Vinylidene fluoride copolymer, tetrafluoroethylene resin (P
Fluororesins such as TFE), tetrafluoroethylene-perfluoroalkoxyethylene copolymer resin (PFA resin), tetrafluoroethylene-hexafluoropropylene copolymer resin (FEP resin); polyvinyl chloride, chlorinated polyolefin, etc. Chlorine resin; Thermoplastic polyester such as polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate; Polyamide such as nylon 6, nylon 12, nylon 6,6, nylon 6,10; Various acrylic resins, etc. alone or in combination of two or more used in combination. Among these, PTFE resin, PFA resin, FEP
Fluororesins such as resins are preferred because they have good charge retention and durability.

[0009] Electrets can be produced by applying any method known per se, such as thermal electretization, electroelectretization, radiation electretization, or photoelectretization, depending on the type of polymer used. It will be done. Thermal electretization method and electroelectretization method are advantageously applied to the above-mentioned polymers, especially fluororesins.

The charge density on the surface of the electret film 11 may be within a range that generates sufficient electrostatic attraction and repulsion for vibration, but is generally 1×10 −
9 to 1×10 −7 C/cm 2 (absolute value) is appropriate, and its polarity does not matter. Furthermore, the thickness of the electret film 11 is arbitrary as long as the vibrations caused by the application of alternating voltages are sufficiently performed, but in general, the thickness is 12.5 to 5.
A range of 00 μm is suitable. Further, the distance between the electret film 11 and the electrode plate 10 is also arbitrary as long as the above-mentioned vibration is sufficiently performed, and is appropriately determined depending on the size of the device and the like. In the above-described apparatus of the present invention, the AC voltage or pulse voltage applied by the AC power source or pulse power source 12 is normally 50 to 1500 V, and the frequency is set so that the ink is effectively atomized. It may be determined experimentally depending on the viscosity of the ink used.

In the apparatus of the present invention, the ink that has been vibrated by the vibration of the electret film 11 as described above is ejected from the nozzle and is continuously separated into uniform particles. The finely divided ink is charged by means known per se, for example, by passing between charging electrode plates, and the charged ink particles are deflected by passing between deflecting electrode plates and sprayed onto recording paper. Ink particles unnecessary for recording are not charged, travel straight without being deflected, and are collected for reuse.

0012

According to the present invention described above, vibrations are imparted to the ink by the vibrations of the electret film without using a piezoelectric element. Therefore, the response speed can be increased compared to conventional ink ejection devices using piezoelectric elements.
For example, it is extremely useful for high-speed recording.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing main parts of an ink ejection device of the present invention.

Claims (1)

[Claims] 1. An ink ejection device used in an inkjet printing system, which consists of an ink chamber equipped with a nozzle at its tip, ink is supplied from an ink tank to the ink chamber via an ink pressure device, and ink is ejected from the nozzle. In the ink chamber, an electrode plate is provided along the ink passage, and a flexible electret film is provided with both ends fixed on the ink passage side facing the electrode plate, and the electrode plate is provided with a flexible electret film fixed at both ends. Alternating voltages are applied to the plate,
An ink ejection device characterized in that the electret film vibrates and ink is ejected from a nozzle tip.