As shown in FIG. 1, a thermomagnetic recording apparatus involves a belt 3 having a magnetic recording layer prepared by coating a macro-molecular film (made of, for example, polyethylene terephthalate, polyimide or the like) of 50-150 .mu.m with a despersion obtained by dispersing a magnetic material such as CrO.sub.2 or the like into a curable organic macro-molecular solvent (such as polyurethane, polyimide or the like), and the belt thus obtained is held endlessly by rolls 1 and 2. Around the rotating belt 3 are provided a permanent magnet 4 magnetizing the belt 3 in a prescribed direction, a heating head array 5 (comprizing another permanent magnet having smaller magnetic force than that of the permanent magnet 4 and reverse magnetizing direction thereto and an array of a heat-generating element made of, for example, ruthenium oxide RuO.sub.2) for forming latent magnetic image on the magnetic recording layer in response to printing signal, a developer 6 for developing the latent magnetic image formed on the magnetic recording layer of the belt 3 by the use of magnetic toner, a pretransferring corotron 7 applying negative charge to the magnetic toner, a transferring means 8 made of a conductive rubber roller and transferring a toner image on the belt 3 to a recording paper by applying a prescribed voltage thereto, and a cleaner 9 or the like composed of a brush with raised soft fibers or blades made of an elastic material and eliminating the magnetic toner remained on the magnetic recording layer of the belt 3.
In the above thermomagnetic recording apparatus, when the roll 1 or 2 is driven by means of a motor (not shown) along the direction of arrow, the belt 3 rotates so that the magnetic recording layer on the belt 3 is unidirectionally magnetized by the permanent magnet 4. When the magnetic reocrding layer magnetized unidirectionally in the belt 3 is heated by heat generation in response to printing signal of the heating held array 5 and simultaneously magnetized in the reverse direction by the permanent magnet, latent magnetic image is formed on the magnetic recording layer of the belt 3. Such latent magnetic image is developed with the magnetic toner to form toner image by means of the developer 6. Negative charge is given to the toner image thus obtained by means of the transferring corotron 7, and the toner image is transferred to the recording paper 10 by means of the transferring means 8 to which positive voltage has been applied. The recording paper 10 onto which the toner image has been transferred is delivered in the direction of arrow, and fixed by means of a fixing means (not shown) thereby completing the recording. Furthermore the magnetic recording layer on the belt 3 is unidirectionally magnetized by the permanent magnet 4, the toner remained on the magnetic recording layer of the belt 3 is removed by means of the cleaner 9, and then the apparatus is prepared for the following recording operations.
CrO.sub.2 used herein as a magnetic material has the following characteristic properties:
Saturation Magnetization .sigma..sub.s : 85-90 emu/g PA0 Coercive Force H.sub.c : 400-600 Oe PA0 Curie Point: 120.degree.-130.degree. C.
As is apparent from the above characteristic properties, since the Curie point is comparatively low, it is possible to write with low energy by the use of CrO.sub.2. (Such prior art as described above is disclosed in, for example, Japanese Patent Laid-open Nos. 36958/1976, 32328/1979, 17372/1981, 26101/1982, 59304/1982, 140307/1982, 180004/1983, 180008/1983, 6031/1966 etc.)
In accordance with a conventional thermomagnetic recording apparatus, Curie point of a chemical compound material used for its magnetic material is determined as the inherent property of the chemical compound material. Thus power consumption becomes higher and the periphery of a heating head array deteriorates thermally in case of utilizing a chemical compound material of high Curie point. On the other hand, where a difference between ambient temperature and a Curie temperature is smaller in employing a chemical compound material of low Curie point, there is such a fear that precision of printing becomes inferior.
USPTO Backgrounds
USPTO Backgrounds