CS227811B1 - Contact printing of magnetic recorded signals - Google Patents

Description

The invention relates to a method of contact copying of magnetically recorded signals with increased transmission of large wavelength signals.

So far, for copying the magnetically recorded signals, contact copying methods have been used, whereby the copy is produced as an imprint of the magnetic state of the original upon mechanical contact of the original carrier with the copy carrier. This increases the ability of the copy carrier to be permanently polarized, either by the action of an external magnetic or thermal field. In the first case, the hysteresis or anhysteresis magnetization process is induced in the copy carrier, in the second case the thermomagnetic process, whereby the coercive force of the copolymer carrier and thus the field size required for irreversible magnetization processes is temporarily reduced. Low-Curie temperature carriers such as chromium dioxide commonly used for magnetic image recording are suitable for thermomagnetic processes.

Its Curie temperature is 120 ° C. At temperatures close to the Curie temperature, the thermomagnetic copying process is significantly more efficient than the magnetic process. Efficiency refers to the ratio of the signal size, ie the copy polarization, to the signal size, ie the original polarization.

The perfection of the contact of the carriers in relation to the wavelength of the copied signal also determines the efficiency of the copying process. As the wavelength of the copied signal decreases, the quality of the contact of the carrier increases.

The advantage of contact copying is its high productivity and direct transmission of recorded information without the double magnetoelectric transformation common in transcription.

The disadvantage of contact copying, especially in magnetic field copying, is the low signal transmission with wavelengths of the order of hundreds of micrometers (caused by the small scattering field of the original).

The disadvantage of thermomagnetic copying is the mechanical deformation of the copy carrier as a whole when heated to temperature, guaranteeing! sufficient efficiency of the thermomagnetic copying process at the point of contact of the carriers. In order for the copy carrier to have a temperature close to the Curie temperature of 120 ° C at the point of maximum contact of the carriers, the temperature of the copy carrier must be substantially higher before contact begins. The decrease in the temperature of the copy carrier is, in particular, caused by the removal of heat to the cool original carrier in the cloud of the onset contact. This also leads to the need for excessive warming of the copy carrier to temperatures > 150 ° C prior to contact. The generally used polyester carrier pads lose strength at temperatures above 120 ° C and become permanently deformed.

Therefore, when reproducing combined recordings with video, audio and control tracks, only the image as a low-wavelength signal is copied in the magnetic field by contact, while a separate device for time-delayed transcription of these signals from the wavelengths must be used to copy the audio and control signal. the original carrier on the copy carrier.

Insufficient transmission of large wavelength signals eliminates to a large extent the method of copying records according to the invention. It is based on ternomagnetic copying of large wavelength and control signals, which is a copying process with lower efficiency, at the point of initial contact between the copy carrier and the original carrier, and copying of small wavelength signals, ie video signal and high frequency spectra magnetically in place of maximum contact of carriers. Copying is sinultánnž.

By the method of contact copying of the magnetically recorded signals according to the invention, a uniform transmission characteristic is achieved throughout the frequency spectrum of the copied signal and there is no need to use a separate device for temporally delayed transcription of these signals from the original carrier to the copy carrier. The copying according to the invention takes place simultaneously.

An arrangement of the apparatus for this copying method is shown in Fig. 1, which is a schematic representation of the copying apparatus, and Fig. 2, showing a detail of its central part. Fig. 3 shows the configuration of the magnetic circuit and the record carrier.

An example of an arrangement of the copying device according to the invention is shown in Fig. 1, wherein the copy carrier 1 is pressed against the original carrier 6 carried by the drum 3 and the flexible pressure roller 6. The copy carrier 1 is heated by the device g prior to contact. The external magnetic fields, the source of which is the magnetic circuit 8 with the winding 2, act at the point of contact.

A detail of the carrier contact area is shown in FIG. 2, where the initial contact area g of the copy carrier and the maximum contact area 3 of the carriers are indicated.

The copy carrier 1 is continuously heated by the device g. Immediately after leaving the heating device 2, when its temperature and hence its ability to magnetize is highest, it meets the cool original carrier g in the region of the initial contact of the carriers fi. The temperature of the copy carrier 1 drops sharply by dissipating heat to the original bearer g, thereby blocking the magnetic polarization of the copy induced in the warm state by the original field. Since the contact of the carriers in the region of the initial contact g is imperfect, only the signals of the large wavelengths (low frequencies of the audio spectrum and the synchronization signals) are copied. The two carriers 1, g proceed together to a maximum contact area g where their contact is naxinal. The temperature of the copy carrier 1 further decreases by transferring heat to the original carrier g and the other parts of the device. At the point of maximum contact g, the magnetic field of the circuit 6 causes a magnetization process in the copy carrier 1, in which the signals of the small wavelengths of the video signal and the high frequencies of the audio signal are copied from the carrier g to the copy carrier 1.

22 ι spekt spectrum. Both magnetization processes result in a copying process with increased transmission efficiency of the high wavelength signal range.

In this method of copying, it is sufficient to heat the carrier of the copy 1 to a lower temperature in the chromium trioxide to 120 ° C than with thermomagnetic copying at a Curie temperature in the region of maximum contact.

For copying the combined video, audio and control recordings, separate magnetic circuits are advantageously used to create a magnetic copy field in the region of the individual recordings and thus to adjust its optimum size. An example of such an arrangement of magnetic circuits and recording tracks is schematically shown in FIG. 3, where the track of the synchronization signal 11 is merged by the magnetic circuit 11. With the winding 12, the trace of the video signal 11, the winding circuit 15 and the track of the audio signal 16 the winding circuit 17. With sufficient retentive polarization of the original synchronization record, the magnetic circuit 11 corresponding to this record can be omitted.

Claims (1)

SUBJECT OF THE INVENTION Method for the continual copying of magnetically recorded signals of different wavelengths, characterized in that the high wavelength signals are copied tentomagnetically at the point where the copy carrier (1) begins to contact the original carrier (2) and the low wavelength signals are copied magnetically at the maximum contact point (1) and the original carrier (2) in the external magnetic field, both thermomagnetic and magnetic copying being performed simultaneously.