JPS603642A - Magnetic recording body - Google Patents

Abstract

PURPOSE:To execute a copying of a high picture quality having no fog on a background part by preventing a leakage magnetic field by a magnetizing pattern of the first magnetic material layer in a non-heated area. CONSTITUTION:For instance, the first magnetic material layer 2 magnetized by a magnetizing pattern modulated periodically in advance extending over the whole surface is provided on a non-magnetic base body 1, and the second magnetic material layer 3 which can be magnetized is provided on said layer. Also, this recording body is constituted so that a relation of an expression I is applied between a saturation residual magnetization M1 and a layer thickness d1 of the first magnetic material layer 2, a saturation residual magnetization M2 and a layer thickness d2 of the second magnetic material layer 3, a wavelength lambda of the magnetizing pattern formed on the first magnetic material layer 2, and each distance l1, l2 from the first and the second magnetic material layer surfaces to the magnetic recording body surface. In this way, a leakage magnetic field in a non-heated area can be prevented, and a copying of a high picture quality having no fog on a background part can be executed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a magnetic recording body, more specifically, to a magnetic recording body, in particular, to at least a base layer, a first element layer having a magnetization/mother turn that changes periodically, and a magnetizable first element layer. The present invention relates to a magnetic recording material comprising a co-magnetic material layer and on the surface of which a magnetic latent image is formed by utilizing a thermal remanent magnetization phenomenon.

Conventional technology A magnetic latent image forming method using thermal residual magnetization is a method in which a ferromagnetic material is heated to around its Curie temperature, cooled to room temperature under the application of an external magnetic field, and then the residual magnetization is removed when the external magnetic field is removed. This method makes use of the phenomenon that occurs, and can obtain remanent magnetization close to saturation remanent magnetization with a smaller external magnetic field than a method of magnetizing using only a magnetic field without using a heating/cooling cycle.

When using this thermal residual magnetization phenomenon to convert heat/turn into a magnetic latent image/4' turn and use it in a magnetic recording method,
Since thermal pattern input methods such as flash light, thermal head, and laser light that contain image information can be used, magnetic latent images can be formed more easily than methods using magnetic heads.

However, in magnetic recording methods that utilize the thermal remanent magnetization phenomenon, heat and a magnetic field must be applied simultaneously.
Furthermore, in order for the magnetic latent image to be effectively developed by magnetic toner or the like, the magnetic latent image itself must be modulated by periodically modulating at least one of the heat and the magnetic field. Various proposals have been made to meet these demands.

First, there is a method in which the magnetic recording medium is previously magnetized once, and then a thermal pattern yi is applied while applying a magnetic field in the opposite direction. This method does not require much positional accuracy of the magnetic field application means and the heat four-turn application means; however,
Since the modulation of the magnetic m-hold depends on the modulation of the thermal A' turn,
Good development cannot be achieved unless the thermal t4 turn itself is further modulated. When a thermal head is used as a thermal reel, spatial magnetic modulation of a wavelength corresponding to the diameter of the thermal head heating element can be performed, but the modulation cannot be applied within a single heat dot. This method has the disadvantage that it is not possible to form dots, and the solid l' punch image becomes a halftone dot image instead of a solid black.

A third method is to form a latent image by simultaneously applying a thermal R-turn and applying a magnetic field using a long ila head or the like. According to this method, the modulation within the latent image can be easily carried out to a desired wavelength by modulating the applied magnetic field, but the heat applying means and the magnetic field applying means can be positioned with extremely high precision. must be set, and the complexity of the installation is unavoidable.

As a third method, the magnetic recording body has a laminated structure in which a seventh magnetic material layer on which a sharply translated magnetization pattern is formed and a magnetizable third magnetic material layer are provided, and the second (a
By applying a heat pattern from the sexual body layer side, the second
There is a method of forming an e-turn (thermal residual magnetization felt in a magnetic layer). This magnetic recording method is a method that allows magnetization modulation to be carried out with a simple arrangement, but in this method (r), the magnetic field due to the magnetization pattern of the first layer required to form thermal remanent magnetization is particularly The toner leaks onto the second layer in the heated region, resulting in fogging of the background during printing and deterioration of the image quality.

As described above, each of the conventional magnetic recording methods has 69 drawbacks, and the reality is that satisfactory effects have not yet been achieved. In particular, in the magnetic recording medium used in the third method,
The magnetization pattern of the first magnetic layer causes thermal remanent magnetization in the co-magnetic layer in the heating region, and the magnetic field formed on the surface of the magnetic recording material due to the thermal remanent magnetization is sufficient to perform magnetic development. Although consideration has been given to the layer thicknesses of the first magnetic layer and the co-magnetic layer so that the magnetic layer has a large size, the leakage magnetic field generated from the magnetization pattern of the first magnetic layer in the non-heated region Thought 1: The soldering is insufficient. Therefore, as described above, when a conventional magnetic recording medium is used, fogging occurs on the spine during development, resulting in a decrease in image quality.

Object of the Invention The object of the present invention is to provide a magnetic recording body consisting of at least a base layer, a seventh magnetic layer in which four turns of magnetization that change periodically, and a magnetizable λ magnetic layer. It is an object of the present invention to provide a magnetic recording medium that enables sieve-quality copying without fogging in the background area by preventing leakage magnetic fields due to the magnetization pattern of the first magnetic layer in the heating region.

Structure of the Invention In the magnetic recording body of the present invention having the above structure, the saturated remanent magnetization M and the layer thickness d□ of the first magnetic layer, the saturated remanent magnetization M and the layer thickness d2 of the first co-magnetic layer, The wavelength λ of the magnetization pattern formed on the first magnetic layer and the distance L from the surface of the first gi layer and the surface of the first magnetic layer to the surface of the magnetic recording body
, t2, the following relationship is substantially satisfied. The wavelength λ of magnetization/yatern is /μm-
Preferably, the value is θOμ. Further, it is preferable that the first magnetic layer thickness d□ and the second magnetic layer thickness d each have a relationship with respect to the wavelength λ of the magnetization i+turn.

Embodiment FIGS. 1(a) to 1(d) show one example of a magnetic d self-recording body according to the present invention.
j': This is an example. In the structure of (a), a first magnetic layer 2 is provided on a non-magnetic substrate 1 in advance, and is magnetized with a periodically modulated magnetization pattern over the entire surface. pl
A first magnetic layer surface capable of magnetization is provided thereon. (+)) is the magnetic quantity when the non-magnetic intermediate J7M4 is provided between the first and second magnetic layers of the structure of (a), ji,
An example of a −ζ body is shown. (C) shows an example in which a surface protective layer 5 is provided on the magnetic recording body having the structure of (a). ((2)(l
(b) An example in which a human face protection layer 5 is provided on a magnetic recording medium manufactured by VF is shown.

Next, a magnet suitable for the magnetic recording medium having the structure shown in Fig. 1, 2□
□□、～. . , gam , (m ”IJ t o.. The first magnetic recording method heats the entire surface of the comagnetic layer,
Step of forming a turn (thermal residual magnetization) corresponding to the magnetization pattern of the first magnetic layer in the first co-magnetic layer (Fig. 2(b))
and inputting a thermal pattern including image information while applying a unidirectional magnetic field from the outside, and setting the thermal residual magnetization pattern corresponding to the heated area of the second magnetic layer in the same direction as the externally applied magnetic field (step 2 (C)).

Figures (a) to (C) will be explained. Figure 2 (a) shows the magnetic state of the magnetic recording medium at 1,000 hours, and the first magnetic layer 2 has magnetization whose direction of magnetization changes periodically as shown by 6 in the figure. A magnetization pattern with a spatial magnetic modulation of 1% is provided over the entire surface. At this stage, the magnetic flux 7 generated from the magnetization 6 in the first magnetic layer 2 is distributed inside the second magnetic layer 3 and on the surface of the magnetic recording body. Here, the magnetic field H (t is the normal environmental temperature TO
The coercive field H2o(TO) of the comagnetic layer is set to be smaller than the coercive field H2o(TO) of the comagnetic layer. Therefore, in the state shown in FIG. 2(a), the comagnetic layer has no residual magnetization, and only the magnet 7 in which four turns 6 of magnetization occur is present on the magnetic recording body.

Figure 1 (b) shows the magnetic air distribution′ after heating the entire surface;
It indicates the magnetic state of the body. As a specific means for heating the entire surface, a flat/unroll lamp, C) roll, or thermal head is used. By being made of a material that changes with temperature as illustrated in , the second magnetic layer 3 has a thermal remanent magnetization pattern 8 that is opposite to the magnetization turn 6 of the magnetic layer 2 of ii\/. become.

Figure 3(a) is a diagram illustrating the temperature dependence of the coercive field HC, which is one of the seven thermomagnetic effects of ferromagnetic materials. Due to the temperature dependence of the coercive field tlc of ferromagnetic materials, as shown in Fig. 3 (
Thermal remanent magnetization phenomenon is caused by heating at a temperature Tb under the application of an external magnetic field H.

11.
This is an L31 phenomenon with thermal remanent magnetization of Mr(Tb).

Returning to FIG. 2(b), the ferromagnetic material that causes the thermal remanent magnetization phenomenon is in the comagnetic material layer 3, the external magnetic field H is in the working magnetic field H1,
The heating temperature TI) is the whole surface heating temperature, and the thermal remanent magnetization Mr(
Tb) corresponds to the Vi magnetization pattern 8, respectively. 1st
If the temperature when the entire surface of the magnetic layer is heated is Tb', and the Curie point temperature of the first magnetic material is Tc', then Tb'(Tc'
By sliding the first magnetic layer with a material that is, the magnetization pattern of the first magnetic layer after heating the entire surface remains unchanged as shown in Figure 2 (a). maintained. Therefore, the magnetic field on the magnetic recording medium in FIG. 2 (1)) is composed of the magnetic flux generated from the magnetization pattern 6 and the magnetization pattern 8.
Since these magnetic fluxes are in opposite directions, the strength of magnetization of the first magnetic body 2 and the second magnetic body 3, the thickness of the j layer, etc. will be described later. By choosing , υ can be made to be O. Figure tb)
In this way, the magnetic recording medium is assumed to be in a state equivalent to that it is apparently not magnetized at all, and the magnetic force that attracts and adheres the magnetic toner does not work at all.

Next, as shown in FIG. 2(C), while applying an external magnetic field H in one direction, a thermal nozzle is applied from the second magnetic layer side to increase the temperature of the non-heated area A1 and the heated area B. turn'
form. Non-heated area A at this time.

It is preferable that the temperature of the heating region B and the external magnetic field H have the same relationships as Ta, Tb, and H shown in FIG. 3(a), respectively. It is preferable that this external magnetic field H causes only the heated region B of the second fli material layer 3 to become thermal remanent magnetized, and does not impart any magnetic shape 2R to other regions or the first magnetic material layer 1. That is, the external magnetic field H is equal to the working magnetic field Hα,
Anti-magnetic field H in the heating area of the first magnetic layer 2. (T
b'), the coercive field H of the non-heated region A of the second magnetic layer 3
2o(Ta) should have the following relationship.

1H1ull-1,1,1)-11<<1)-I□C(
Tb' month, 1) -126 (Ta) for l>l → - bile 7
1 By doing this, a magnetic state as shown in FIG. 2(C) can be obtained. In FIG. 2(C), the first magnetic layer 2 maintains the same reverse magnetization pattern as in FIG. 2(a). The non-heated region A of the second magnetic body N3 is the second
Although it has a magnetization pattern reversed with respect to the first magnetic layer as in FIG. 2B, the heated region B is uniformly magnetized in the same direction as the external magnetic field H due to the thermal residual magnetization phenomenon.

A magnetic layer that is uniformly magnetized in one direction, such as the heating region B of the third magnetic layer, generates almost no magnetic flux to the outside and is almost equivalent to a case where it is not magnetized at all. Therefore, the magnetic state of FIG. 2(C) is the same as that of FIG.
), and in the non-heating area A, the magnetic field on the magnetic recording medium is approximately Q in the non-heating area A, and in the heating area B, the magnetic field is due to the magnetization turn 6. It turns out. Therefore, a magnetic latent image is formed which corresponds to the image-shaped applied heating pattern and which is modulated in accordance with the magnetization pattern 6 of the first magnetic layer 2.

The external magnetic field H used here only needs to exist until the imprint heating pattern cools and disappears, and a permanent magnet, an electromagnet, etc. can be used as the external magnetic field imprinting means. (When positioning) Skin etc. are very relaxed.

Erasing the latent image formed in this manner can be accomplished by heating the entire surface in the absence of an external magnetic field to bring it into the magnetic state shown in FIG. 2(b). Therefore, forming and erasing a magnetic latent image can be easily performed by the series of steps shown in FIG. 1 (1) and (C). Part 2 about the relationship between strength and layer thickness, etc.
This will be explained with reference to FIG. 7(b).

Generally, a magnetic layer such as the first magnetic layer 2 or the second magnetic layer 3 is magnetized at a constant wavelength λ. In this case, the magnetic field at a point located a distance y from the surface of the magnetic layer is given by:

Therefore, the magnetization and layer thickness of the first magnetic layer are set as M and d,
The residual saturation magnetization and layer thickness of the co-magnetic layer are set to M2. Assuming CI2, the magnetic field formed by the magnetization M□ of the first magnetic layer on the 42 magnetic layer is as follows.On the other hand, the residual saturation magnetization M2 of the second magnetic layer forms on the second magnetic layer The magnetic field becomes . If each value is determined as follows, the magnetic field on the surface of the magnetic recording medium can be made zero. Therefore, Figure 2 (C)
When a heat pattern containing image information is applied as in
In the non-heating region A, no leakage magnetic field is generated on the surface of the magnetic recording body plate.

The wavelength λ of magnetization has an effect on the developability, especially the image density and the fineness of the image. This is suitable because when the magnetization wavelength λ is short, the fineness of the image is excellent, but if it is too short, the magnetic field decreases quickly and the developing power weakens. .Also, the magnetization of a magnetic material is
Residual saturation magnetization is suitable from the viewpoints of strong magnetization, ease of control, magnetic stability, etc. moreover,
Anisotropicizing the magnetic material so that the axis of easy magnetization is in the direction in which the magnetic material is to be magnetized strengthens the residual magnetization of the magnetic material Jh'r and improves developability.

Equation (force) is an important factor in a magnetic recording medium having a structure as shown in Fig. 2 (a) to (C). It can also be extended to magnetic recording media with .The general formula is given by.

Since the magnetization of the magnetic layer depends on the material or magnetic properties of the magnetic layer, it is preferable that the magnetic layer has the following materials and magnetic properties.

The first magnetic layer is required to form a magnetic field strong enough to reach the magnetic recording medium, and to have the property that its own magnetization does not change even when heated or applied with an external magnetic field. Therefore, the first magnetic layer has high magnetic stability against heat, has a Curie point temperature of λθθ°C or more, and is made of a material with high residual magnetization Br and coercive force HC, such as Co-N1-
A P alloy magnetic thin film or a so-called metal teso in which fine particles of iron or the like are dispersed in a polymer resin are passed through. The residual saturation magnetization of this metal teso can pass through the second magnetic layer, etc. in the 200θ~gooo Gaussian, heating range to form a sufficient magnetic field (see Figure 2 (0) 4.
As for the two magnetic material layers, the thermal remanent magnetization phenomenon mentioned earlier is
A magnetic material is used. Furthermore, a magnetic material in which this thermoremanent magnetization yl phenomenon occurs at a relatively low temperature is desirable, such as a dispersed coating type CrO2 magnetic material layer with a Curie point temperature of about /3oC, and rare earth materials such as Tb-1.'t Gd=/'≧. Metal-transition metal amorphous alloy thin films are suitable. These residual saturation magnetizations are on the order of Sθθ~i'soo Gauss, which is smaller than that of the seventh magnetic layer, but since the magnetic layer is located close to or on the surface of the magnetic body, the first magnetic layer is formed. It is possible to create a magnetic field with a strength equivalent to that of the magnetic field.

The thickness of the first magnetic layer and the second magnetic layer tends to be such that the generated magnetic field becomes stronger as the layer thickness becomes thicker, but even if they are made thicker, there is little effect, so the periodic magnetization pattern / / wavelength λ 2DOλ to 2λ is appropriate. Although the intermediate layer does not need to be provided, it is effective when used as a heat insulating layer to keep the first magnetic body in a stable state.
This is particularly effective when the first magnetic layer and the second magnetic layer JM are made of materials having similar Curie point temperatures. however,
If the intermediate layer is too thick, the magnetic field on the magnetic recording body formed by the magnetization of the first magnetic layer, that is, the latent image of the magnetic recording body, will be too weak. is desirable. In addition, the surface protective layer is also the second magnetic layer (,:
When the mechanical strength is high, it is desirable to provide the surface with an abrasion-preventing property, but it is preferable that the thickness be as thin as possible.

FIG. 7 shows an example of a magnetic recording device in which a magnetic recording body 10 according to the present invention can be used. A first magnetic layer 2 consisting of a non-magnetic polyimide intermediate layer 4, and a second magnetic layer 3 consisting of a CrO2 dispersed coating layer are laminated in this order. The magnetic recording body 10 is rotationally driven in the clockwise direction, and around it are a whole surface heating means 11 and a heat transfer applying means 12.
, external magnetic field applying means 13, developing device 14, transfer roll 15
A sweeping means 17 is arranged at and 7.

A flash rung is used as the entire surface heating means 11, which heats the second magnetic layer 3 to 730°.
Due to the thermal residual magnetization phenomenon, a magnetization no.

The magnetic recording body 10, whose apparent upper magnetization has been erased, is then subjected to a magnetic field (approximately 2
00 Oersted), it is heated in an imagewise manner by a heat or turn applying means 12 consisting of a thermal head, and a magnetic latent image is formed. The magnetic latent image formed in this way is sent to a developing device 14, where it is visualized by adhering magnetic toner, and then transferred to a transfer roller 15 to which a bias voltage is applied.
The image is transferred onto the recording paper 16. On the other hand, the magnetic recording medium 10 is sent to a cleaning device 17, where residual magnetic toner is removed. When making multiple copies, develop these,
After repeating the transfer and seeding process to obtain the desired number of copies, the entire surface is heated with a flash lamp and magnetic 62
e is erased and the next latent image forming step begins.

In the magnetic recording device shown in FIG.
When using a magnetic recording material of z#, that is, the first magnetic layer 1 has a saturation residual magnetization of 2 g00 Gauss and a thickness of 3 μm.
A sine wave magnetization pattern with a wavelength of θμm is used as the intermediate layer 4, and a polyimide layer with a thickness of sμII+ is used as the comagnetic layer 3.
When a CrO2/Vi'11 layer having a layer thickness of S .mu.m is used, copies made by the magnetic recording device have an image density of 7.3 and an extremely good image without background stains.

-A magnetic recording material that completely deviates from the conditions of the 10th λ equation, the clear is residual magnetization, 2g θθ force, layer thickness 3μm, wavelength 60μ? When an image was formed using a first magnetic layer formed of gold with a sinusoidal magnetization pattern of n and a second co-magnetic layer with a residual RRFI magnetization of 300 Gauss layer thickness and no intermediate layer, The 8A degree of both images is better than that of Hiroshi, but the background is so dirty that it is difficult to obtain a good-looking image.

The magnetic recording medium according to the present invention can be used not only for the above-mentioned non-reversal surface image forming method, but also for the magnetic recording medium shown in FIGS.
It can also be used in a reversal latent image forming method as shown in C).

By this method, it is possible to obtain the inverted 7f'j image in Fig. 1 (cl
[It is obtained by applying the external eel tattoo at the step 1 stone of the external eel tattoo H (b) that has been applied at C. In other words, Figure 3 (
A reversal magnetic latent image can be obtained by applying the same external magnetic field while heating the entire surface as shown in 1)), and then applying heat/magnetic waves in the absence of an external magnetic field as shown in Figure S (c). I can do it. Erasure of the magnetic latent image is achieved by heating the entire surface, thereby returning to step (a). To continue magnetic recording, heat the entire surface and apply a unidirectional external magnetic field! ? All you have to do is go back to step (b). Even in such a reversal (...) image forming method, the magnetic field on the surface of the recording medium is 0 in heating tilt B, and there is no leakage magnetic field in areas where magnetic toner should not adhere. .

When using such a reversal magnetic latent image forming method, in the magnetic recording apparatus shown in FIG. 5. Alternatively, by controlling the external magnetic field applying means, the entire surface heating means and the thermal pattern applying means may be used both.

Effects of the Invention The magnetic recording body of the present invention can prevent magnetic field leakage in the non-imaging area on the surface of the magnetic recording body by using a simple magnetic (3) forming method. It is possible to produce high quality images without capri. In addition, the early magnetic recording medium tζ of the present invention can form a reversal magnetic latent image by a simple reversal magnetic latent image forming method.
You can obtain high-quality images without pre-printing. Further, by using the magnetic recording body of the present invention, it is possible to serve both as a whole-surface heating member and a thermal pattern applying member by controlling the external magnetic field, and it is possible to promote miniaturization and multifunctionality of magnetic recording devices. Further, by controlling whether or not to apply a magnetic field when applying a thermal pattern, it is also possible to arbitrarily delete or add to an existing magnetic m-image.

[Brief explanation of the drawing]

FIGS. 1(a) to (d) are partial cross-sectional views showing the structures of various magnetic recording bodies to which "KIENYU" can be applied, and FIGS. Figures 3 (a) and (b) show the magnetic remanent magnetization phenomenon kf of ferromagnetic materials. In the graph, (a) shows the coercive force Hc (
7) shows a temperature change curve, (1)) shows a thermal remanent magnetization curve with respect to an external magnetic field H, FIG. S diagrams (a) to (C) are (1G recording process diagrams) for explaining the reversal magnetic latent image forming method that can be used in the magnetic recording medium of the present invention. 1. Base layer 2. 1. Magnetic layer 3... 1st co-magnetic layer 4... Intermediate layer 5... Surface protective layer 10... Magnetic recording body 11... Full surface heating means 12... Heat/Gaturn applying means 13... External magnetic field applying means 14... Developing device 15... Transfer roll 16... Recording paper 11... Cleaning device 6 Figure 3 (b) Figure 4 Figure 7

Claims (1)

[Claims] (1) In a magnetic recording body consisting of at least a base layer, a first magnetic layer on which a periodically changing magnetization pattern is formed, and a magnetizable co-magnetic layer, the saturation residual magnetization M of the first magnetic layer □ and layer thickness d□, saturation residual magnetization M2 and layer thickness d2 of the first co-magnetic layer, wavelength λ of the magnetization pattern formed in the first magnetic layer, surface of the first magnetic layer and second magnetism. A magnetic recording body configured such that the following relationship is approximately established between distances t and t2 from the surface of the magnetic recording body to the surface of the magnetic recording body. (A) The magnetic recording medium according to claim 4, characterized in that the wavelength λ of the periodically changing magnetization/mother turn formed in the first magnetic layer is /μgt −!; θ0 μm. (j The first magnetic layer thickness d and the second magnetic layer thickness d2 are:
Claims 1 and 4 are characterized in that each periodic magnetization curve formed in the first magnetic layer has a relationship with the wavelength λ.
Magnetic recording medium described in Section 1.