JPS6024590Y2 - magnetic fluid recording device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a magnetic fluid recording device capable of recording with less noise than conventional devices by improving the gate electrode.

FIG. 1 shows the configuration of the main parts of a conventional magnetic fluid recording device.

In FIG. 1, a magnetic fluid 4 contained in an ink tank 5 is supplied to the tip of a needle electrode 2 through a supply path 3 made up of a magnet, and a bump is formed by the magnetic force.

A voltage pulse from a high voltage switching circuit 9 controlled by a needle electrode control circuit 10 is applied to the needle electrode 2.
The ferrofluid bump at the tip becomes electrically charged.

On the other hand, a voltage pulse from a high-voltage switching circuit 7 controlled by an image signal control circuit 8 is applied to the gate electrode 1, and charges are induced on the surface of the recording paper 6 that is in contact with the gate electrode 1.

When the electric field created by the charge at the tip of the needle electrode 2 and the charge on the surface of the recording paper 6 exceeds a certain value, the magnetic fluid is blown away by Coulomb force and reaches the surface of the paper.

FIG. 2a shows the structure of the gate electrode, which consists of gate electrodes 15 arranged at a pitch of 200 μm on the polyimide soil rim 14 and an input connector 16.

Note that 16 needle electrodes are opposed to each gate electrode.

Therefore, image recording can be performed by applying an image signal to the gate electrode while sequentially scanning the needle electrode.

FIG. 2 is an enlarged view of the gate electrode 15.

15a is an electrode, and 15b is a lead foil.

For the purpose of explanation, both ends of the electrode are designated as A and B.

FIG. 3 shows how a conventional gate electrode is attached.

15a is a gate electrode, 14 is a polyimide film 14
a is a base film, and 14b is a cover film that covers the gate electrode lead foil 15b.

These are adhered to a cylindrical base material 17. Recording paper 18
moves in the direction of arrow 19 while being in close contact with the gate electrode.

20 is a recording position where the magnetic fluid flies from the needle electrode.

The recording position 20 is positioned approximately at the center of the gate electrode 15a.

The conventional device having the above configuration has the following problems.

When there is an image signal and then there is no image signal, that is, in the case of a signal as shown in the timing waveform diagram shown in FIG. 4, the magnetic fluid flies even in the portion 21 where there is no image signal, resulting in noise.

In other words, in the recording state, when moving from a black part to a white part, noise is likely to appear in the white part.

This is due to the following reasons.

Here, FIG. 5 shows the charge distribution on the surface of the recording paper when an image signal is applied to the gate electrode 15a in FIG.

The solid line indicates the state at the moment when the image signal is applied, and the broken line indicates the next moment.

20 is the recording position described above.

After the image signal is applied, the recording paper moves in the direction of arrow 19.

At this time, the charged area (range from A to B) on the surface of the recording paper is
The arrow 19' moves along with the recording paper while discharging to some extent.
It will look like a broken line.

In other words, at the recording position 20, charges generated by the previous image signal remain, and a state in which recording is possible even in the absence of an image signal may occur, which tends to generate noise.

The above malfunctions vary somewhat depending on the recording speed, the charging characteristics (discharge characteristics) of the recording paper, etc., but the faster the recording speed is, the less the charging characteristics (discharge characteristics) of the recording paper can follow, and the more likely noise is to occur. There was a drawback.

The present invention solves the above-mentioned conventional drawbacks, and provides a magnetic fluid recording device which improves the structure of the gate electrode section, reduces noise generation, and is particularly effective during high-speed recording.

FIG. 6 shows a cross section of a main part of an embodiment of the present invention.

The gate electrode 15 is an electrode 15a similar to the conventional example shown in FIG.
One side of the lead foil 15b is in contact with a polyimide base film 14a, and the lead foil 15b is covered with a cover film 14b.

The gate electrode 15 uses its base film 14a as a base material 17.
At this time, electrode 1
The tip A of the electrode 15a coincides with the recording position 20, and the lead side edge B of the electrode 15a is in the recording paper traveling direction (arrow 1) from the tip A.
9).

FIG. 7 shows the charge distribution on the surface of the recording paper due to voltage application to the gate electrode 15.

Here, the solid line is the moment when an image signal is added, and the broken line is the next moment when no image signal is present.

At this time, the potential on the recording paper with respect to the recording position 20 becomes a sufficiently high potential when the image signal is applied, and recording is performed.
When there is no image signal at the next moment (corresponding to white), the potential drops rapidly and becomes approximately O potential, so the magnetic fluid does not fly, and therefore noise generation is extremely reduced.

Note that by arranging the electrode 15a of the gate electrode as in the present invention, the actual recording position (the position where the magnetic fluid adheres) is slightly closer to the lead side end than the tip A compared to the illustrated recording position 20. The position will be closer to B.

This is due to the influence of the density of the electric lines of force, but experiments have shown that this shift distance is very small and does not pose any problem in image formation.

As is clear from the above embodiments, according to the present invention, it is possible to improve the response of the charge on the recording paper corresponding to the recording position, and it is possible to reduce recording noise in areas that should be white. This is particularly effective in improving image quality during high-speed recording.

[Brief explanation of the drawing]

FIG. 1 is a main part configuration diagram showing a conventional magnetic fluid recording device;
Fig. 2 shows the main parts of the conventional device, a is a block diagram of the entire gate electrode, b is an enlarged view of the gate electrode, Fig. 3 is a block diagram showing the attachment part of the conventional gate electrode, and Fig. 4 is a block diagram of the entire gate electrode. FIG. 3 is a timing waveform diagram of an image signal according to the configuration, FIG. 5 is a charge distribution characteristic diagram according to a conventional configuration, FIG. 6 is a main part configuration diagram showing an embodiment of the present invention, and FIG. FIG. 3 is a charge distribution characteristic diagram of this example. 15... Gate electrode, 15a... Electrode, 15b... Lead foil, 17... Base material.

Claims (1)

[Scope of utility model registration request] a needle electrode made of a magnetic material arranged opposite to the recording paper; a magnet that comes into contact with the tip of the needle electrode to magnetize the needle electrode and cause a magnetic fluid to adhere to and bulge on the tip of the needle electrode; A supply means for supplying a fluid, a gate electrode opposed to the needle electrode via a recording paper, and a voltage application means for applying a voltage corresponding to an image signal between the needle electrode and the gate electrode. , the gate electrode has a long shape in the recording paper running direction, and when both ends in the recording paper running direction are defined as an A end and a B end, respectively, the A end is aligned with the position facing the needle electrode, and the gate electrode is What is claimed is: 1. A magnetic fluid recording device, characterized in that the recording paper is moved in the direction from the A end to the B end.