JPS5828384A - Magnetofluid recording device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention The present invention provides a magnetic fluid recording method in which a magnetic fluid is raised on a magnetic multi-stylus by magnetic force, and the raised magnetic fluid is caused to fly by applying a Coulomb force to print on a recording surface. The present invention relates to a device, and provides a magnetic fluid recording device that can smoothly and reliably supply magnetic fluid onto the magnetic multi-stylus in the initial stage before printing, and can obtain an image without irregularities or blurring of the print. It is something that I try to do.

FIG. 1 and FIG. 2 schematically show the structure of a conventional magnetic fluid recording device. A multi-stylus 1 is mounted on a substrate 5, and a bump magnet 2 for magnetizing the multi-stylus 1 is adhered onto the multi-stylus 1. A slit magnet 3' is attached opposite the uplift magnet 2, forming a slit-shaped magnetic fluid holding portion. A magnetic fluid holding container 4 is attached below the bump magnet 2 and the slit magnet 3, and the parts other than the magnetic fluid holding part and the drain 1o are sealed. The holding container 4 is connected to a magnetic fluid tank 13 via a pump 12 by a vibrator 11 connected to a drain 10.
is connected to. The pump 12 pushes up the magnetic fluid to fill the holding container 4, and the pump is stopped when the magnetic fluid 6 is attached to the bump magnet 2. The bump magnet 2 and the slit magnet 3 are arranged with the same poles facing each other, and a shield plate 2' made of magnetic metal is provided on the opposing surface.
, 3' are respectively attached, the lines of magnetic force are concentrated in the vicinity of the magnetic fluid holding part M, and the magnetic fluid strongly adheres to the magnetic fluid holding part M, thereby sealing the magnetic fluid holding part M. Therefore, even if the pump is stopped, this state is maintained without air flowing into the holding container 4, and the bump is raised according to the head H from the tip of the multi-stylus 1 to the magnetic fluid liquid level in the magnetic fluid tank 13. 7. can be formed. When a voltage is applied between the multi-stylus 1 and the control electrode 8 by the voltage applying means 14, a Coulomb force acts near the tip and end of the bump 7, and the magnetic fluid 6 flies toward the recording medium 9.
A print is thus obtained on the recording medium 9. However, in such a configuration, when the pump 12 pushes up the magnetic fluid to adhere the magnetic fluid to the bump magnet 2 in the initial stage before printing, the holding container 4 on the lower side of the slit-shaped magnetic fluid holding portion Air bubbles are trapped in the area between the uplift magnet 2 and the slit magnet 3 inside the drain 10.
This has the disadvantage that the supply of the magnetic fluid to the magnetic fluid holding section is obstructed.

This drawback will be explained below using the drawings. When the magnetic fluid in the magnetic fluid tank is pushed up by the pump 12, the magnetic fluid passes through the pipe 11, and as shown in FIG. 3a, the magnetic fluid is first filled from the bottom of the magnetic fluid holding container 4. It will be done. As shown in FIG. 3, when the liquid level of the magnetic fluid in the holding container 4 rises to a certain level, the magnetic fluid is sucked up by the magnetic force of the bump magnet 2 and the slit magnet 3. As mentioned above, since the magnetic force near the magnetic fluid holding part M is very strong, the magnetic fluid sucked up by the magnetic force of the bump magnet 2 and the slit magnet 3 immediately adheres to the magnetic fluid holding part M. The magnetic fluid holding portion 4 becomes sealed, and bubbles B as shown in the figure form in the holding container 4. When the liquid level of the magnetic fluid in the holding container 4 further rises, the amount of magnetic fluid adhered to the magnetic fluid holding part M is small at first, and the sealing force is weak, so that the bubbles B are larger than the magnetic fluid holding part M. 'The holding container 4 is filled with magnetic fluid as it slips out little by little, but when the holding container 4 is filled with magnetic fluid to a certain extent, the magnetic fluid flows as shown in Figure 3C. The amount of magnetic fluid attached to the body holding part M increases, the sealing force also becomes stronger, and even if pressure is applied by the pump to forcibly supply the magnetic fluid into the holding container 4, the bubbles B will not come out at all. .

Further, when the magnetic fluid is forcibly supplied, the magnetic fluid flows along the walls of the uplifting magnet 2 and the slit magnet 3, and furthermore, the magnetic fluid flows through the uplifting magnet 2 and onto the multi-stylus 1. The air bubble B cannot be completely removed as shown in FIG. 3d. Like this,
With air bubbles accumulated in the area sandwiched between the bump magnet 2 and the slit magnet 3 inside the magnetic fluid holding part M, the pump 12 is stopped and a predetermined bump 7 corresponding to the height H is formed. When printing, the flow path of the magnetic fluid is narrowed by the air bubbles inside the magnetic fluid tank 5, so that while the magnetic fluid is consumed from the tip of the protuberance 7, the magnetic fluid flows from the drain 1'O. The supply of magnetic fluid to the body holder cannot keep up, resulting in irregular or blurred printing.

As explained above, in the conventional configuration, air bubbles tend to accumulate inside the magnetic fluid holding part, and these air bubbles cannot be completely removed. There was a major drawback in that it was not possible to smoothly supply the stylus to the holder, and furthermore, it could not be smoothly supplied from the bumping magnet 2 onto the multi-stylus 1, resulting in irregular or blurred printing.

Generally, a larger amount of magnetic fluid tends to adhere to hot water layers where the magnetic flux density is high and where the rate of change of magnetic flux density is large. FIG. 4a shows the relationship between the amount of attached magnetic fluid and the magnetic flux density H when the rate of change of the magnetic flux density with respect to distance is kept constant. FIG. 4 is a graph showing the relationship between the amount of attached magnetic fluid and the rate of change in magnetic flux density with respect to distance when the magnetic flux density is kept constant. As shown in FIG. 4, a larger amount of the magnetic fluid adheres to areas where the magnetic flux density is large and where the rate of change of magnetic flux density with respect to distance is large. FIG. 5 shows the distribution of magnetic lines of force in a general magnet and how the magnetic fluid is attached. Figure 5 & ! :
! L' represents the magnetic field line distribution of one magnet 20 and the adhesion state of the magnetic fluid. This figure shows the distribution state of magnetic lines of force and the adhesion state of the magnetic fluid when they are placed in close contact with each other. Figure 6 a, a
As shown in ', in the case of only one magnet 20,
Since the magnetic lines of force are concentrated at the edge portions E, /', G, and H of the magnet 1, a large amount of magnetic fluid adheres to the edge portions E, F, G, and H. However, when the same magnetic poles are brought into close contact with each other in the direction of repelling the magnet 21 from the magnet 20 as shown in Fig. 6, b', the lines of magnetic force are more concentrated at the edges F and H on the side where they are brought into close contact. , the magnetic flux density and the rate of change of the magnetic flux density with respect to distance become larger, and the magnetic fluid also becomes smaller than the magnet 2o.
Although it adheres in a larger amount than when it is attached alone, at the edge parts E and G on the side opposite to the side where the magnet 21 is brought into close contact, the concentration of magnetic lines of force is reduced, and the magnetic flux density and the rate of change in magnetic flux density with respect to distance are smaller. Therefore, compared to the case where the magnet 20 is used alone, the magnetic fluid hardly adheres.

The present invention has been made with this point in mind, and one embodiment thereof will be described below.

FIG. 6 shows a schematic configuration of the first embodiment of the present invention, and FIG.
, b respectively show the operating principle of the first embodiment of the present invention.

In the figure, a multi-stylus 1 is mounted on a base 6, and a bump magnet 2 for magnetizing the multi-stylus 1 is adhered onto the multi-stylus 1.

A magnetic fluid holding container 4 is attached below the bumping magnet 2, and a slit magnet 3 is attached to face the bumping magnet 2, forming a slit-shaped magnetic fluid holding portion. are doing. The bump magnet 2 and the slit magnet 3 are arranged so that the same magnetic poles face each other, and a shield plate made of magnetic metal is attached to each opposing surface as in the conventional case. The parts other than the magnetic fluid holding part and the drain 10 are sealed, and the holding container 4 is connected to the magnetic fluid tank 13 via a pump 13 via a pipe 11 connected to the drain 1o. A magnetic fluid detection sensor 15 is attached near the bump magnet, and a guide 5 plate 16 is attached to the slit magnet 3. An external magnet 19 is provided along the guide plate 16 so as to be movable toward and away from the slit magnet 3, and is connected to a shaft 171 of a plunger 17 attached to the rear of the guide plate 19.

Further, the external magnet 19 is arranged so that the same magnetic pole (in this case, the N pole) faces the slit magnet 3. The plunger drive circuit 18 is configured to operate in response to a detection signal from the magnetic fluid detection sensor 15, thereby driving the plunger 17.

The operation of this device will be explained below.

Initially, before a magnetic fluid is attached to the bump magnet 2 and a predetermined bump 7 is formed on the multi-stylus 1, an external magnet is attached to the slit magnet 3 so that the same magnetic poles are aligned with each other as shown in FIG. 7a. They are in close contact with each other in the direction of repulsion, and as explained in FIG. 5, the magnetic flux density of the edge portion B of the slit magnet 3 and the rate of change of the magnetic flux density with respect to distance are extremely small. Therefore, also in the magnetic fluid holding portion, the magnetic flux density and the rate of change of the magnetic flux density with respect to distance are extremely small. When the magnetic flow in the magnetic fluid tank 13 is pushed up by the pump 12, the magnetic fluid passes through the pipe 11 and is filled from the bottom of the holding container 4. As shown in FIG. 7, the liquid level of the magnetic fluid in the holding container 4 rises to some extent, and the magnetic fluid is blown up to some extent by the magnetic force of the bump magnet 2 and slit magnet 3. However, as mentioned above, the magnetic fluid holding part A
The magnetic flux density and the change in magnetic flux density with respect to distance are very small. Therefore, as explained in FIG. not sealed. Therefore, even if the liquid level of the magnetic fluid in the holding container 4 is further increased, the bumping magnet 2
As shown in FIG. 7C, the magnetic fluid holding portion is completely filled with the magnetic fluid without any air bubbles between the magnetic fluid and the slit magnet 30. When the magnetic fluid sensor 16 detects that the magnetic fluid is sufficiently attached to the magnetic fluid holding portion, the plunger 17 is driven by the plunger drive circuit 18 and the shaft 1 of the plunger 17 is driven.
7 moves in the direction of arrow C, the external magnet 19 separates from the slit magnet 3, and the lines of magnetic force become concentrated on the edge part B of the slit magnet 19, and therefore the lines of magnetic force are also concentrated on the magnetic fluid holding part M. As a result, the magnetic flux density and the rate of change of the magnetic flux density with respect to distance become large. In such a state, the magnetic fluid will strongly adhere to the magnetic fluid sensor person, and even if the pump 12 is stopped, the magnetic fluid holding part will remain sealed and air will not enter the holding container 4. This state is maintained without any inflow, and as shown in FIG. 6, a protuberance 7 is formed in accordance with the head H from the tip of the multi-stylus 1 to the magnetic fluid liquid level in the magnetic fluid chamber 13. I can do it. FIG. 8 shows a second embodiment of the invention. In this embodiment, instead of the external magnet 19, an electromagnet 19' is attached closely to the slit magnet.
When a magnetic fluid is not detected by the magnetic fluid sensor 15, the electromagnet 1 is activated by the electromagnet drive circuit 18.
The side where 9' is in close contact with the slit magnet in the direction in which the slit magnet is repelled is magnetized so that the magnetic pole is the same as the magnetic pole of the contact surface of the slit magnet. When a magnetic fluid is detected by the magnetic fluid sensor, the electromagnet drive circuit 181 stops and the electromagnet 19' loses its magnetic force, so the operation is exactly the same as that of the first embodiment. effect can be obtained.

Note that as the magnetic fluid detection sensor, for example, a current detection type sensor as shown in FIG. 9 can be used. Specific examples are shown below. The two electrodes 22 are opposed to each other with a predetermined interval, and a voltage is applied between the two electrodes 22 by a power source 23 via a resistor R.

As shown in FIG. 6a, the magnetic fluid is connected to the electrode 18.
When the electrodes 22 are not attached to each other, the resistance between the electrodes 22 is infinite, and the voltage Vs across the resistor 8 is OV.

However, as shown in FIG. 9, when the magnetic fluid 6 adheres to the tips of the electrodes 22 and bridges the electrodes 22, the magnetic fluid has a conductivity of about 106 to 1010 Ω. A voltage Vs corresponding to the voltage of the power supply 23, the resistance of the magnetic fluid attached between the electrodes 22, and the resistance R is generated across the resistor H. The voltage Vs across this resistor R can be used as a detection signal for the magnetic fluid.

As explained above, according to the present invention, it is possible to attach the magnetic fluid to the magnetic fluid holding portion without creating air bubbles in the magnetic fluid holding container, and therefore, the pump can be stopped and the magnetic fluid flows from the tip of the multi-stylus. When printing is performed by forming a bump corresponding to the drop to the magnetic fluid liquid level in the body tank, the supply from the drain to the magnetic fluid holding part is not obstructed, and high quality printing can be achieved stably. Obtainable.

[Brief explanation of drawings]

Figure 1 is a side view showing a conventional magnetic fluid recording device, Figure 2 is a side view showing a conventional magnetic fluid recording device;
The figure is a front view of the same main part, Figures 3 a to d are explanatory diagrams of the same operation, and Figure 4 is a front view of the same main part.
Figures a and b are diagrams showing the relationship between the amount of attached magnetic fluid, magnetic flux density, and rate of change in magnetic flux density, respectively, and Figure 5 a and a'
, b, b' are diagrams explaining the principle of the present invention, FIG. 6 is a side view of a magnetic fluid recording device in an embodiment of the present invention, FIGS. 7 a-, -d are diagrams explaining the same operation, and FIG. 9 is a side view of another embodiment of the present invention, and FIGS. 9a and 9b are explanatory views of the operation of the magnetic fluid sensor. , 2°...magnetic shield plate for elevation, 3.
... Slit magnet, 31 ... Slit magnet shield plate, 4 ... Magnetic fluid holding container,
6...Base, 6...Magnetic fluid, 7
... Protuberance, 8 ... Control electrode, 9 ...
...Recording body, 10...Drain, 11...
...Pipe, 12...Pump, 13...
... Magnetic fluid tank, 14... Voltage application means, 15... Magnetic fluid sensor, 16...
・Guide plate, 17...Plunger, 18...
... Plunger drive circuit, 18'... Electromagnet drive circuit, 19... External magnet, 19'...
...Electromagnet, 20.21 ...Magnet. Name of agent: Patent attorney Toshio Nakao is under the name of φ・1 351 ((1) (b) (C)
(d)
Figure 4 [α) (b) Figure 5 Figure 6 Figure 87 Figure 75g (C) (d) Figure 8 Figure 9 ((1) (b) Procedural Amendment (Direction N) 7, 1982 February 5, 15゛Indication of the case, Mr. Commissioner of the License Agency, 1986 Patent Application No. 1260929 2. Name of the invention: Magnetofluidic recording device 3. Relationship to the person who makes the amendment Patent application Person: Kadoma City, Osaka Prefecture Oaza Kadoma 1006 address name
(582) Matsushita Electric Industrial Co., Ltd. Representative Yama
Toshihiko Shimo 4 Agent 571 Address 1006 Oaza Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. 6 Date of amendment order January 2e, 1980 Contents of amendment (1) From line 3 on page 8 of the specification Line 16 “Figure 6 is...
... Figure 6 shows the magnetic field line distribution of a general magnet and the way the magnetic fluid adheres to it. The distribution of magnetic lines of force and the adhesion state of the magnetic fluid are shown in Figures 6C and 6d, which show the lines of magnetic force when two magnets with the same magnetic properties are placed in close contact with one magnet 20 facing each other in the direction of repelling another magnet 21. It shows the distribution state and the adhesion state of the magnetic moving body.As shown in Fig. 6a and b, in the case of only one magnet 2°, the edge portions E, F of the magnet 1, Since the magnetic lines of force are concentrated at G.H, a large amount of magnetic fluid adheres to the edge portions E.F, G, and H. However, as shown in FIGS. If the same magnetic poles are brought into close contact with each other in the direction that repels 21, it will be corrected to ``. (2) Page 16, line 4 [Figure 5 a, a'...
``Principle of the present invention'' will be corrected to ``Figure 6 a, b, c, and d are the principle of the present invention.'' (3) Correct Figure 6 as shown in the attached sheet. Figure 5 I

Claims (1)

[Claims] (1) a magnetic multi-stylus recording electrode provided facing the recording surface; a bumping magnet provided in contact with the tip light value on the recording electrode to bump the magnetic fluid onto the recording electrode; A slit-shaped magnetic flow '
A head section having a slit component made of a magnetic material provided opposite to the protrusion magnet so as to form a moving body holding section, and a magnetic fluid storage section provided below the head section; a conduit connecting a slit-shaped magnetic fluid holding section and the magnetic fluid storage section; and a conduit for transporting the magnetic fluid in the magnetic fluid storage section through the conduit to the slit-shaped magnetic fluid holding section. and a supply means for supplying the magnetic flux, and the slit-shaped means is provided in the vicinity of the head portion, and the magnetic flux distribution is controlled at least when no magnetic fluid is attached to the slit-shaped magnetic fluid holding portion. A magnetic fluid recording device configured as described above by driving a changing means. (2. In claim 1, the magnetic flux distribution changing means provided in the vicinity of the head portion is provided with an external magnet that is provided so as to be able to move toward and away from the head portion, and an external magnet that moves the external magnet toward and away from the head portion. A magnetic fluid recording device characterized in that it is constituted by a separating means and K (@ In claim 1, the magnetic flux distribution changing means provided in the vicinity of the head section is an electromagnet. Magnetofluidic recording device.