JPS6217544B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic ink recording device that uses magnetic ink in which magnetic particles are dispersed in a dispersion medium, raises the magnetic ink on a multi-stylus using magnetic force, and flies it using Coulomb force. The purpose is to prevent print quality from deteriorating due to concentration segregation of the magnetic ink that adheres to the magnet that guides the ink to the recording needle when left unused for a long period of time, and to obtain good images. It is.

FIG. 1 shows a conventional magnetic ink recording device. Magnetic ink 1 is magnetically guided from an ink tank 2 to a recording head 4 by a magnet 3. The recording head 4 includes a plurality of recording needles 5 with good magnetic permeability, a substrate 6, and a raised magnet 7.
and a shield plate 8. The magnetic ink 1 is attached in a state that corresponds to the balance between the magnetic force of the recording head 4 and the gravity at the distance h between the liquid level of the ink tank 2 and the tip of the recording needle 5. In this state, when a voltage is applied to the recording needle 5 from a power source (not shown), the magnetic ink 1 flies in the direction of arrow A.
The system is such that the reduced amount of ink is sequentially supplied from the ink tank 2. However, if left in this state for a long period of time, the magnetic particles in the magnetic ink 1 will be attracted to the area of the recording head 4 where the lines of magnetic force are concentrated, resulting in concentration, as shown in FIGS. 2 and 3. For this reason, the viscosity of the concentrated magnetic ink increases, which inhibits the fluidity of the ink, and when printed, the print quality deteriorates, such as the print becoming blurred.
The present invention eliminates the above-mentioned drawbacks,
An object of the present invention is to provide a magnetic ink recording device that prevents concentration of magnetic ink and does not cause deterioration in print quality even when left unused for a long period of time. An embodiment of the present invention will be described below with reference to FIGS. 4 and 5. FIG. 4 is a block diagram of a magnetic ink recording apparatus according to an embodiment of the present invention.

Magnetic ink 1 is stored in ink tank 2 and recording head 4.
The recording head 4 is guided to the recording head 4 by a capillary tube 10 connecting the recording head 4 to the recording head 4. Recording needle 5 of raised magnet 7 of recording head 4
A non-magnetic material 11, such as resin, is fixed in a convex shape to the portion in contact with the shield plate 8 and the joint portion with the shield plate 8. This shape is such that the nonmagnetic material 11 includes all the parts where the product (H・dH/dl) of the magnetic field strength H and the magnetic gradient (dH/dl) is larger than a predetermined value. It is preferable to determine the surface shape of No. 11. The reason is that the attraction force F due to the magnetic force of magnetic particles is F∝
This is because it is determined by H・dH/dl, and as shown in Figure 5, according to experiments, if it is below a certain H・dH/dl, the thermal diffusion energy of the magnetic particles is strong and it is difficult to concentrate, but the magnetic field lines In areas where the magnetic particles are concentrated, especially in areas close to the magnet surface, H·dH/dl becomes extremely large, causing concentration of the magnetic particles due to the magnetic force. Therefore, if the ink is allowed to adhere at a predetermined distance from the magnet surface, the concentration can be significantly reduced and can be kept to a level that poses no practical problem.

Further, instead of the capillary tube 10 used in this embodiment, a material exhibiting capillary action such as a sponge may be used. In this embodiment, the magnetic ink 1 is supplied from the ink tank 2 to the recording head 4 through a capillary tube 10.
However, as shown in FIG. 1, a magnet 3 may be used to supply the magnetic ink 1 to the recording head 4. Also in this case, it is still more effective to arrange a non-magnetic member at the location where the lines of magnetic force are concentrated.

As described above, according to the present invention, the problem of concentration of magnetic ink that conventionally occurs when left unused for a long period of time can be solved simply by fixing a non-magnetic material, and even after long periods of time left unused, good print quality can still be maintained. It is possible to provide a magnetic ink recording device that can maintain high performance.

[Brief explanation of the drawing]

Figure 1 is a configuration diagram of a conventional magnetic ink recording device.
Fig. 2 is an explanatory diagram showing the concentration state of the recording head section of the same device, Fig. 3 is a magnetic field line distribution diagram of the same head, and Fig. 4 is an explanatory diagram showing the concentration state of the recording head section of the same device.
This figure is a block diagram of a magnetic ink recording apparatus according to an embodiment of the present invention, and FIG. 5 is a characteristic diagram showing changes in the concentration of magnetic ink in a magnetic field. DESCRIPTION OF SYMBOLS 1... Magnetic ink, 2... Ink tank, 3... Magnet, 4... Recording head, 5... Recording needle, 6... Substrate, 7
... Raised magnet, 8... Shield plate, 10... Capillary tube, 1
1...Nonmagnetic material.

Claims (1)

[Claims] 1. In an apparatus for recording by depositing magnetic ink on the surface of a magnet, supplying the magnetic ink to the tips of a plurality of magnetic recording needles, and causing the ink to fly from the tips of the recording needles using Coulomb force, 1. A magnetic ink recording device, characterized in that a non-magnetic member is disposed on the surface of the magnet, so that magnetic ink does not adhere within a predetermined distance from the surface of the part of the magnet where lines of magnetic force are concentrated.