JPS63165148A - Electrostatic acceleration type ink jet recording apparatus - Google Patents

Abstract

PURPOSE:To inexpensively obtain a back electrode suitable for obtaining a high quality recording image, by constituting the back electrode so as to have such a structure that an electric conductive fine wire is provided under tension in parallel to the longitudinal direction of a slit like ink jet orifice. CONSTITUTION:A back electrode 11 is obtained by fixing one end of an electric conductive fine wire to the back electrode fixing member 15 provided between back electrode tensioning mount substrates 13, 14 and connecting the other end thereof to a fine wire take-up mechanism to wind the fine wire around said take-up mechanism and providing the electric conductive fine wire between back electrode support members 12, 12' under tension. The back electrode 11 is regulated and fixed so that the end surfaces of the back electrode tensioning mount substrates 13, 14 on the side opposed to an ink recording head, that is, the end surface of the back electrode 11 on the tensioning mount side thereof becomes a plane containing a straight line A-A, and recording paper 4 is fed in the state brought into contact with the end surfaces of the back electrode substrates 13, 14. The leading end parts of the recording electrodes 21 arranged at predetermined arrangement density in the longitudinal direction of a slit like ink jet orifice are arranged in the slit like ink jet orifice in parallel to the back electrode 11 mounted under tension.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to an electrostatic acceleration type inkjet recording device, and more particularly, to an electrostatic acceleration type inkjet recording device having a slit-shaped ink jet orifice. This relates to improvement of the back electrode.

(Prior Art) Electrostatic acceleration type inkjet recording devices using slit-shaped ink jetting ports have been known.

In the slit-shaped ink jet recording device of the above-mentioned electrostatic acceleration type inkjet recording device, a large number of recording electrodes are arranged in the longitudinal direction of the slit-shaped ink jet, as disclosed in, for example, Japanese Patent Laid-Open No. 56-170. When a voltage pulse corresponding to a recording signal is selectively applied to the plurality of recording electrodes, the ink near the tip of the recording electrode to which the voltage pulse has been applied is arranged opposite to the slit-shaped ink ejection port. The ink is attracted and accelerated by electrostatic force in the direction of the back electrode, which is attached to the recording paper that has been placed between the slit-shaped ink jet orifice and the back electrode, thereby forming ink dots on the recording paper.

The slit-shaped ink jet nozzle of the electrostatic acceleration type inkjet recording device described above uses a member with a large number of recording electrodes arranged on one side of a glass plate or a printed circuit board as the lower plate for forming the slit-shaped ink jet nozzle. It is made by stacking slit-shaped ink jet nozzle forming upper plates on the surfaces with a predetermined gap in between.

In addition, a metal plate or a metal roller is arranged on the back electrode facing the slit-shaped ink jetting port so as to be parallel to the longitudinal direction of the slit-shaped ink jetting port.
While keeping the recording paper in contact with the surface of the back electrode 1,
The recording device is configured such that the ink passes between the ink ejection port and the back electrode.

It is known that the ink ejection characteristics of an inkjet recording device having the above structure vary depending on the shape of the slit-shaped ink ejection port, the physical properties of the ink such as surface tension and conductivity, and the hydrostatic pressure applied to the ink. In order to improve the quality of recording, it is important to form ink jet ports with a uniform shape over the longitudinal direction of the ink jet ports.

That is, if there is a missing portion at the tip of a slit-shaped ink ejection port provided with a recording electrode, ink will not be ejected from that portion, and no ink will be ejected from the protruding portion.

There are disadvantages in that the ink is easily ejected and the diameter of the ink dot is significantly larger than other parts.

The ink to which a recording signal is applied from the recording electrode is attracted and accelerated toward the back electrode by electrostatic force and adheres to the recording paper, so the shape of the back electrode also causes the above-mentioned problems.

In other words, the back electrode has protrusions, depressions, undulations, etc., and the distance from the tip of the recording electrode disposed inside the slit-shaped ink jet port to the back electrode differs for each recording electrode. It has been difficult to form ink dots with a uniform diameter on the recording paper over the entire length of the outlet in the longitudinal direction.

In order to solve these problems, the end face of the member forming the slit-shaped ink jet port is precisely polished to increase its flatness, and when a metal plate is used for the back electrode,
When using a metal roller for the back electrode by increasing the flatness of the electrode surface facing the slit-shaped ink jet orifices, methods have been adopted to increase the cylindricity and coaxiality of the metal roller with respect to the roller rotation axis.

(Problems to be Solved by the Invention) What is the method for improving the recording quality of the electrostatic acceleration type inkjet recording apparatus described above in the prior art?

The objective was to be achieved by precisely machining the recording electrode and back electrode, respectively, which had the problem of requiring a large number of man-hours.

The present invention aims to solve the above-mentioned problems and to provide a back electrode suitable for obtaining high-quality recorded images at low cost.

[Structure of the invention]

(Means for Solving the Problems) The present invention selectively applies a voltage pulse corresponding to a recording signal to a large number of recording electrodes disposed within a slit-shaped ink jet orifice, and A potential difference is generated between the opposing back electrode and the ink near the recording electrode to which a voltage pulse has been applied is sucked and ejected from the slit-shaped ink jet orifice toward the back electrode. In an electrostatic acceleration type inkjet recording device that forms ink dots on recording paper interposed therebetween.

The electrostatic acceleration type inkjet recording device is characterized in that the back electrode has a structure in which an electrically conductive thin wire is stretched parallel to the longitudinal direction of the slit-shaped ink jet orifice.

That is, by stretching electrically conductive thin wires to form the back electrode, a highly straight back electrode is obtained and the above-mentioned problems are solved.

Hereinafter, the content of the invention will be explained in detail using the drawings.

FIG. 1 is a perspective view of an ink recording head portion of an electrostatic acceleration type ink jet recording apparatus equipped with a back electrode showing one embodiment of the present invention.

The back electrode 11 has one end of the electrically conductive thin wire attached to a back electrode fixing member 15 provided between the back electrode stretching substrates 13 and 14.
After being fixed to the wire, the other end is connected to a thin wire winding mechanism 15' (not shown) and wound up, and the electrically conductive thin wire is stretched between the back electrode support members 12 and 12'.

FIG. 2 is a schematic cross-sectional view of the support portion of the back electrode 11 and the ink recording head obtained by the method described above.

In FIG. 2, the end surfaces of the back electrode stretching substrates 13 and 14 facing the ink recording head, that is, the back electrode (1
1) The end face on the stretching side is adjusted and fixed so that it becomes a plane including the straight line A-A', and the recording paper ± is conveyed in a state in which it is in contact with the end faces of the back electrode substrates 13 and 14.

The tip of the recording electrode 21 arranged in the slit ink jet in the longitudinal direction of the slit ink jet at a predetermined arrangement density is connected to the stretched back surface il! It is arranged parallel to tiii.

As the electrically conductive thin wire for the back electrode used in carrying out the present invention, tungsten wire has a high Young's modulus and is suitable for strongly stretching and obtaining a highly straight back electrode, as well as stainless steel thin wire and carbon wire. Fibers etc. can also be used.

Further, the surface of the polymer fiber may be imparted with electrical conductivity.

As for the diameter of the electrically conductive thin wire used, if the material is the same, a thinner one is advantageous because it can be stretched with less tension.

(Function) The back electrode according to the present invention is supported at two points by the back electrode support member, and a highly straight back electrode can be obtained.

In other words, the tips of all the recording electrodes of the many recording electrodes arranged in the slit-shaped ink ejection port are at the same distance from the back electrode so that the electric field strength between the recording electrode and the back electrode generated by the application of the recording signal pulse is equalized. It has an effect.

(Example) Two alumina substrates with a long side of 80 mm, a short side of 40 mm, and a thickness of 1 m were used as back electrode substrates, and a polyester film with a thickness of 100° was used as a back electrode support member by laminating them with adhesive. integrated.

Thereafter, a back electrode was obtained by stretching a tungsten wire having a diameter of 60 cm between two alumina substrates using the back electrode member as a fulcrum.

Next, the short side is 50m, the long side is 80++a, and the thickness is 21m.
The width in the longitudinal direction of the glass plate is 60. A slit-shaped ink jet nozzle forming lower plate in which chromium metal recording electrodes are installed at a ratio of 8/■, polished from the side where no recording electrodes are provided, and the glass plate at the tip of the recording electrode is processed into a knife shape. and a glass slit-shaped ink jet nozzle forming upper plate whose one long side is similarly processed into a knife shape, with a thickness of 100 mm.
The back electrode is separated by a gap of 400 μs from the tip of the slit-shaped ink jet port integrated through the m spacer.
An electrostatic acceleration type inkjet recording device having the recording section structure shown in FIG. 1, which was arranged facing each other, was obtained.

Above, the thickness between the back electrode and the slit-shaped ink jet port is 8
After arranging the 0- recording paper, fill the slit-shaped ink ejection port with ink for electrostatic acceleration type inkjet recording device, and apply a pulse @600μsec to the selected one mark @flL pole.
, a recording signal pulse with a peak value of -250 V is applied, and a pulse width of 600 μsec and a peak value of +1900 V is applied to the back electrode side.
As a result of applying an ink acceleration voltage pulse of V in synchronization with the recording signal pulse, a diameter of 0.12 ff is printed on the recording paper.
An ink dot of ffiI was formed.

The same recording operation was performed for each of the other recording electrodes in the slit-shaped ink jetting ports, and as a result, the diameter of the ink dots formed on the recording paper was 0.10 to 0.12.
It was distributed within a range of mm.

On the other hand, similar to the conventional electrostatic acceleration type inkjet recording device, the diameter of the ink dot recorded under all the same recording conditions as described above except that a metal cylinder was used as the back electrode was o, It was distributed over a wide range of io■ to 0.25 kaku.

〔Effect of the invention〕

According to the present invention, it is possible to easily obtain a back electrode with high straightness, so it is easy to reduce variations in the distances from the tips of the many recording electrodes arranged in the slit-shaped ink jet ports to the surface of the back electrode. It is possible to obtain an electrostatic acceleration type inkjet recording device that can perform high-quality recording with uniform ink dot size.

Further, the number of man-hours required for increasing the flatness and cylindricity of the back electrode required in the conventional device can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a back electrode and its surrounding area of an electrostatic acceleration type inkjet recording apparatus according to the present invention. FIG. 2 is a schematic cross-sectional view of the back electrode and its surrounding area of the electrostatic acceleration type inkjet recording apparatus according to the present invention. 11... Back electrode 12, 12'... Back electrode stretching support member 13, 14.
...Back electrode stretching substrate 15...Back electrode fixing member 21...Recording electrode 2
2... Lower plate for forming slit-shaped ink jet ports 23... Upper plate for forming slit-shaped ink jet ports 24... Ink tank 3-... Ink soil... Recording paper agent Patent attorney Yudo Nori Chika Kikuo Takehana

Claims (5)

[Claims] (1) Voltage pulses corresponding to recording signals are selectively applied to a large number of recording electrodes disposed within a slit-shaped ink jet orifice, and a potential difference is created between the slit-shaped ink jet orifice and a back electrode disposed opposite to it. The ink near the recording electrode to which a voltage pulse has been applied is suctioned and ejected from the slit-shaped ink jetting port toward the back electrode, forming ink dots on the recording paper interposed between the slit-shaped ink jetting port and the back electrode. An electrostatic acceleration type inkjet recording device characterized in that the back electrode has a structure in which an electrically conductive thin wire is stretched parallel to the longitudinal direction of the slit-shaped ink jet port. (2) An electrostatic acceleration type inkjet recording device according to claim 1, characterized in that an electrically conductive thin wire used as a back electrode is stretched in a gap formed between two electrically insulating members. . (3) A patent claim characterized in that the material of the two electrically insulating members constituting the gap in which the electrically conductive thin wire is stretched is made of a wear-resistant material such as alumina porcelain glass or quartz glass. The electrostatic acceleration type inkjet recording device according to item 2. (4) The ends of the two electrically insulating members forming the gap in which the electrically conductive thin wire is stretched are parallel to the electrically conductive thin wire. An electrostatic acceleration type inkjet recording apparatus according to claim 2 or 3. (5) Any one of claims 2 to 4, characterized in that the electrically conductive thin wire constituting the back electrode is made of tungsten wire, nickel wire, or nichrome wire. electrostatic acceleration type inkjet recording device.