Magnetic recording reproducing apparatus with field generating means within the copy medium

Informations recorded in a master medium are first magnetically transferred to a temporary copy medium. The transferred informations are repeatedly reproduced with at least one reproducing magnetic head. The feature of the invention resides in the magnetic transfer means wherein the magnetic transfer field is generated from mechanically rotating or oscillating permanent magnet means.

BACKGROUND OF THE INVENTION 
The present invention relates to a magnetic recording reproducing apparatus 
and, more particularly, relates to a magnetic recording reproducing 
apparatus adapted to repeatedly reproduce or read out recorded 
informations or signals from magnetic tapes or cards. 
Heretofore, magnetic recording medium has been widely used as an economical 
and effective medium for storing informations or signals in the form of 
tape, disc, card or sheet in various fields including education, 
entertainment, office labor saving, data storage and the like. 
The present invention relates, particularly, to a magnetic tape or card 
reproducing apparatus of the type wherein the informations or signals in a 
magnetically recorded tape or card (hereinafter called "master medium") 
are once magnetically transferred to a unrecorded temporary magnetic 
medium (hereinafter called "copy medium") by the contact type magnetic 
transfer method (this is also called "magnetic printing" in the art) and 
then the transferred informations are repeatedly reproduced from the copy 
medium with a conventional magnetic reproducing head. As is well known in 
the art, the contact type magnetic transfer is characterized in that a 
master medium provided with a magnetic recording surface having a coersive 
force greater than that of a copy medium is superposed on the copy medium 
with their magnetic recording surfaces contacting each other and an A-C 
magnetic field is applied to the contact area of these media. The magnetic 
field is gradually reduced from a maximum value at which the magnetic 
recording surface of the copy medium is magnetically saturated or nearly 
saturated but the recorded signal of the master medium is not 
substantially effected, so that the hysteresis loop of the copy medium is 
gradually shifted to minor loops under the influence of the magnetic field 
of the master medium. It is also well known that the quality of the thusly 
transferred signals or informations is high. 
It has already been proposed to obtain the necessary magnetic field for the 
transfer or printing by using an AC electromagnet energized from an AC 
current source. Advantages resulting from the magnetic transfer or 
printing are that (1) the original signals such as sound signals or image 
signals recorded on the master medium are not adversely affected nor 
erased and (2) the signals of the master medium which have been 
transferred to the copy medium can be repeatedly reproduced. These 
advantages are important particularly in the field of language training 
because of the capability of repetitive reproduction of the same sounds of 
the master medium. For example, in the case where the master medium is in 
the form of a card having one or more short length of magnetically 
recorded tracks and the copy medium is in the form of a short length of an 
endless tape (though the copy medium need not form an endless loop so long 
as any given point of the copy medium repeatedly arrives at the same 
reproducing head), the same sounds transferred to the copy medium can be 
reproduced periodically or repeatedly so long as the copy medium is being 
driven. In another example, image signals recorded in a master medium can 
be repeatedly reproduced on a Braun screen from a copy medium which has 
signals transferred from the master medium. Further, by recording a 
computer program on a master medium in the form of a card, the same 
program can be repeatedly produced and applied to input terminals of a 
computer. Further example would be found in the facsimile field wherein an 
incoming facsimile image is once recorded on a master medium and then 
magnetically transferred to an endless copy medium which is then inked 
with magnetic toners and finally transferred to sheets of paper several 
times. Thus, the system of this type is effectively utilized in education, 
entertainment, man power saving and the like. 
However, the conventional magnetic recording reproducing apparatus provided 
with a magnetic transfer arrangement utilizing an AC current source 
required an electromagnet, an energizing circuit for the electromagnet and 
an AC current source. For example, a separate oscillating circuit was 
required in a reproducing apparatus of battery type. 
In the conventional compact apparatus wherein a battery is used, there was 
a defect that a major part of the power is consumed in the oscillating 
circuit. This made difficult the utilization of the magnetic transfer 
method in such small portable apparatus. 
BRIEF SUMMARY OF THE INVENTION 
Accordingly, a primary object of the present invention is to provide a 
magnetic recording reproducing apparatus of the magnetic transfer type 
which eliminates the AC current source, the complicated circuits and the 
members associated therewith. 
Another object of the present invention is to provide a magnetic recording 
reproducing apparatus of the magnetic transfer type wherein permanent 
magnet means or DC magnet means is utilized for generating a magnetic 
transfer field, whereby the AC current source, the complicated circuit and 
the members associated therewith are eliminated. 
A further object of the present invention is to provide a magnetic 
recording reproducing apparatus for repeatedly reproducing informations 
such as sounds, images, pulses and the like from a master medium with use 
of permanent magnet means or DC magnet means as magnetic transfer field 
generating means, whereby the disadvantages of the conventional repetitive 
reproducing apparatus are eliminated. 
Yet another object of the present invention is to provide a repetitive 
magnetic recording reproducing apparatus which eliminates the AC power 
source for generating a magnetic transfer field. 
According to the present invention, a magnetic recording reproducing 
apparatus is provided which comprises magnetic transfer field generating 
means consisting essentially of mechanically rotating or mechanically 
oscillating permanent magnet means and/or DC magnet means. More 
particularly, the present magnetic recording reproducing apparatus 
comprises a recorded master medium, a unrecorded copy medium, means for 
advancing said master medium and said copy medium through an area of 
contact where the magnetic surfaces of both media are brought into contact 
with each other, means for generating and applying an alternate magnetic 
field to both media at said area of contact, said means consisting 
essentially of mechanically rotating or oscillating permanent and/or DC 
magnet means having a plurality of alternately arranged pole pieces, a 
magnetic reproducing head for reproducing the transferred signals or 
informations of the copy medium, and means for driving said copy medium in 
such manner that any given point on the magnetic surface of the copy 
medium is repeatedly advanced past said magnetic reproducing head. 
Briefly, the characteristic feature of the present invention resides in the 
use of permanent magnet means and/or DC magnet means as means for 
generating the necessary magnetic transfer field. The present invention is 
technically and economically superior to the conventional magnetic 
recording reproducing apparatus which uses an electromagnet of a high 
frequency or a commercial frequency (50Hz or 60Hz) primarily because of 
elimination of oscillating circuit. Further, it is preferable to use the 
same permanent magnet means or DC magnet means for erasing the copy 
medium. As already pointed out, the conventional apparatus utilized an AC 
current source as means for generating the magnetic transfer field, the 
frequency of which is 50Hz or 60Hz, and the current from such AC current 
source was passed through a coil mounted on a ring magnetic core provided 
with a small gap. The magnetic field leaked from the gap was utilized as a 
transfer field. By suitably designing the circuit for energizing the coil 
so that the gap is adapted to selectively generate both a magnetic 
transfer field and an erasing field (the erasing field may be large enough 
to erase the master medium, if necessary), it was possible that the same 
magnet core could serve the purpose of erasing the medium, too. In the 
present invention, too, similar effect is attained. 
The advantages resulting from the present invention are, as partly pointed 
out in the foregoing, elimination of an AC current source for generating a 
magnetic transfer field and an erasing magnetic field, if necessary, 
compactness of the apparatus, and provision of a permanent magnetic source 
for the magnetic transfer field and erasing magnetic field source, if 
necessary. 
The present invention will be fully described in the following explanation 
in connection with the accompanying drawings.

DETAILED DESCRIPTION OF THE INVENTION 
Referring to FIGS. 1, 2 and 3 which illustrate a magnetic recording 
reproducing apparatus according to the first embodiment of the present 
invention, a master medium m is illustrated as a sound recorded card or a 
language training card. The master card m comprises a carrier or substrate 
1 formed of paper or a synthetic resin and a magnetic medium 2 on which a 
sound signal has been recorded. The magnetic medium 2 has a coercive force 
of about 600 Oe. One surface of the substrate 1 (the rear surface of the 
card in FIG. 2) has characters, figures and/or pictures such as "DOG", 
etc. The pronunciations of the characters or the like or an explanation on 
the characters or the like is recorded on the magnetic medium 2. 
Referring to FIG. 1, p is a copy medium which is clearly illustrated in 
FIG. 3. In FIG. 3, the copy medium p comprises a drum 3 which opens to one 
side and a magnetic medium 5 formed on the annular periphery 4 of the drum 
3. The wall of the drum 3 on the other side is fixedly supported by a 
shaft 6 which is driven by way of suitable reduction means from an 
electric motor (not shown) in the direction indicated by an arrow 12. The 
coercive force of the magnetic medium 5 of the copy medium p is less than 
that of the magnetic medium 2 of the master medium m. For example, it has 
about 300 Oe. A pinch roller 7 is fixedly mounted on a rotating shaft 9, 
the axis of which is parallel to the axis of the drive shaft 6. The 
peripheral surface of the pinch roller 7 is covered with a resilient and 
frictional material 8 such as rubber, silicone rubber or a plastic 
material. Referring to FIG. 1, the annular periphery 4 of the drum 3 is 
opposed to the surface 8 of the pinch roller 7, so that when the master 
medium m is inserted between the pinch roller 7 and the peripheral surface 
4, the master medium m is advanced in the direction shown by an arrow 20. 
To insure positive engagement of the master medium m with the copy medium 
p, the pinch roller 7 is normally spring biased as indicated with an arrow 
10. 
The peripheral length of the annular periphery 4 and, accordingly, the 
length of the magnetic medium 5 should be longer than the length of the 
magnetic medium 2 on the master medium m. The magnetic media 2 and 3 must 
be brought into contact with each other when the master medium m is 
inserted between the drum 3 and the pinch roller 7. To this end, there is 
provided means for guiding the master medium. Such guide means is 
conventional and hence is not illustrated in the drawings. It will suffice 
to point out that the guide means provides a transverse control so that 
the track or magnetic medium 2 is always registered with the track or 
magnetic medium 5 in the transverse direction. 
A reproducing head h is disposed at a location adjacent to the annular 
periphery 4 of the drum 3 in such manner that the gap portion of the head 
h engages the magnetic medium 5 under the action of a spring (indicated by 
an arrow 25). The head h is preferably supported by a movable frame which 
allows the head to be moved between the position illustrated in FIG. 1 
(reproduction period) and a position (not shown) removed from the drum 
periphery 4 (transfer or printing period or cease period). Additional 
reproducing heads h', h". . . may be used, if desired. In such case, 
reproduced sounds from the plurality of the reproducing heads may be 
effectively utilized for producing multiple reproduction effect or echo 
effect, etc. 
The inside of the drum 3 is hollow and opens to one side as already 
described. A magnetic field generating means in the form of a rotary body 
15 is provided within the drum 3 as shown in FIG. 1. The rotary body 15 
has a plurality of equally spaced permanent magnets 16 having alternate 
different polarities along its circumferential periphery. Preferably, the 
permanent magnets 16 are embedded in the peripheral portion of the rotary 
body 15 in such manner that the longitudinal axis of each of the magnets 
16 extends in the radial direction and alternate pole pieces N and S of 
the magnets 16 sre exposed to the air at the outermost ends. The rotary 
body 15 is fixedly supported by a central shaft 17 which, in turn, is 
rotatably supported by a bearing (not shown) on a base (not shown). The 
shaft 17 is driven by an electric motor (not shown) which may be common to 
the drive source for the shaft 6 of the drum 3. The direction of rotation 
of the rotary body 15 is either clockwise as shown by an arrow 13 or 
counterclockwise as shown by an arrow 14. Alternatively, the rotary body 
15 may be oscillated in both directions 13 and 14. The axes of the shaft 
17, shaft 6 and the pinch roller 7 are parallel and lie substantially in 
the same plane, so that the magnetic field generating means and 
accordingly each pole piece N or S of the permanent magnets 16 applies the 
maximum magnetic field to the area of contact between the master medium m 
and the copy medium p. Since the peripheral surface of the drum 3 is made 
from a non-magnetic material such as non-magnetic metal or sunthetic 
resin, the magnetic field generated from the permanent magnets 16 passes 
through the drum surface 4. 
In operation, insertion of the master medium m between the drum 3 and the 
pinch roller 7 actuates a suitable start switch (not shown) by engagement 
of the master medium m with the switch. This places the drum 3 in rotation 
at a predetermined velocity. For easy understanding of the invention, let 
us assume that the drum 3 is rotated at a peripheral velocity of 5 cm/sec 
and the master medium m has a record for a period of time of 5 seconds at 
a linear velocity of 5 cm/sec (i.e., the length of the record is 25 cm). 
At the same time, the magnetic field generating means or the rotary body 
15 is placed in rotation upon actuation of the start switch in the 
direction shown by the arrow 13 or 14. The rotational velocity of the 
rotary body 15 must be so high that the magnetic field successively 
applied to the area of the contact between the master medium m and the 
drum surface 4 meets the requirements for the magnetic transfer field as 
explained before. Preferably, it is convenient to use a common electric 
motor which is directly connected to the shaft 17 of the rotary body 15 
and also is connected through a reduction means to the shaft 6 of the drum 
3 to drive the drum at a circumferential velocity of 5 cm/sec. The master 
medium m is urged against the periphery 4 of the drum 3 and, with the 
rotation of the drum, is fed in the direction indicated by an arrow 20 at 
a linear velocity of 5 cm/sec. The magnetic medium 5 of the drum 3 and the 
magnetic medium 2 of the magnetic medium m are registered by guide means 
and brought into contact to each other. By selecting the peripheral length 
of the drum is at least 25 cm, the recorded signal on the whole length of 
the magnetic medium 2 is magnetically transferred to the magnetic medium 5 
of the copy medium p. By selecting beforehand the positional relation 
between the shaft 17 and the contact area between the master medium m and 
the copy medium p at such a distance that the magnetic field from the 
permanent magnets 16 at this contact area is just the effective magnetic 
transfer field, the signal recorded in the magnetic medium 2 can be 
transferred to the magnetic medium 5 without substantially affecting the 
recorded signal of the master medium. After the master medium has passed 
the contact area, the pinch roller 7 is moved in the direction reverse to 
the arrow 10 so as to remove the pressure on the drum 3. 
The shaft 17 of the rotary body 15 is rotatably supported by a bearing 
block (not shown) which is slidable vertically when viewed in FIG. 1. This 
bearing block is supported by an elevating mechanism (not shown) which is 
adapted to automatically move the rotary body 15 together with the bearing 
block downwardly into position as shown in FIG. 1 when the master medium m 
is inserted in the apparatus and automatically move the rotary body 15 
upwardly into a rest position when the trailing edge of the master medium 
m clears the pinch roller 7. Accordingly, after the master medium m has 
cleared the pinch roller 7 the copy medium p will receive little magnetic 
field. 
After the master m has cleared pinch roller 7, the magnetic reproducing 
head h is brought into contact with the copy medium p (or it may contact 
the copy medium at all times), while continuing the rotation of the drum 3 
in the direction indicated by the arrow 12. The reproducing head h 
continuously reads out the information or signal recorded on the magnetic 
medium 5 of the copy medium so long as the drum 3 is being rotated. Thus, 
the repetitive reproduction of the recorded signal is made possible. 
If the operator or user desires to stop or terminate the reproduction from 
a particular magnetic medium or to reproduce another magnetic medium, he 
operates a stop switch (not shown) which terminates the repetitive 
reproduction. This stop switch may be associated with erasing operation or 
a separate erasing switch may be provided. When the apparatus is set in 
the erasing operation, the bearing block of the rotary body 15 is 
automatically moved down to a position where the magnetic field generated 
from the permanent magnets 16 is sufficiently great to saturate magnetic 
medium 5 of the copy medium p. It is noted that the position of the rotary 
body 15 is closer to the peripheral surface 4 of the drum 3 than that 
shown in FIG. 1. Thus, though not illustrated in the drawings, the support 
for the bearing block for the rotary drum 15 is so constructed that the 
rotary drum 15 is selectively and automatically positioned in either one 
of three predetermined positions (i.e., a rest position, a magnetic 
transfer position and a magnetic erasing position) in response to switch 
or circuit operation. If desired, the present apparatus may have a 
function of erasing the master medium m. For example, the rotary body 15 
can be indexed to another position which is further closer to the 
peripheral surface of the drum than the above-mentioned erasing position. 
From the foregoing, the first embodiment of the present invention has 
provided a magnetic recording reproducing apparatus wherein transfer and 
repeated reproduction of signals of a master medium are easily made by 
utilizing an endless copy medium in the form of a drum and a plurality of 
rotating permanent magnets disposed within the drum to generate the 
necessary magnetic transfer field. Further, adjustment of the position of 
the rotary body with respect to the copy medium makes it possible to 
utilize the same rotary body as a magnetic transfer field generating means 
as well as a magnetic erasing field generating means. Further, the erasing 
field may be adjusted, if desired, so as to adapt it to erasure of both 
master medium and the copy medium. 
The embodiment described above utilizes an elevating mechanism for 
adjusting the positions of the rotary body bearing a plurality of 
alternate permanent magnets. Alternatively, instead of changing the 
position of the rotary body 15, a magnetic shield may be removably 
inserted between the rotary body 15 and the copy medium p. For example, a 
sheet of a magnetic material of high magnetic permeability such as 
"Supermalloy", Ni-Zn ferrite, etc. 
FIG. 4 illustrates another embodiment of a magnetic transfer and erasing 
field generating means which can be used in the embodiment illustrated in 
FIG. 1 in place of the rotary body 15 with necessary modifications. The 
rotary body in FIG. 4 has a fixed axis of rotation instead of the movable 
axis of the rotary body in FIG. 1. More specifically, the rotary body 
comprises a magnetic transfer field generating part P and an erasing field 
generating part E mounted on the same shaft 17. The part P consists of a 
rotary body 15' provided with a plurality of permanent magnets 16' having 
uniformly spaced alternate polarities N and S along the circumferential 
surface of the rotary body 15'. The part E consists of a rotary body 15" 
having a similar construction to the rotary body 15' but having a larger 
diameter than the rotary body 15'. The rotary body 15" has a plurality of 
permanent magnets 16". The assembly in FIG. 4 is used in place of the 
rotary body 15 in FIG. 1 with obvious change or modification. The shaft 17 
is adapted to be moved in its axial direction with a suitable indexing 
mechanism (not shown) in such manner that either one of the rotary body 
15' and the rotary body 15" is selectively registered with the position of 
the magnetic medium 5 of the copy medium p, or the assembly can be 
entirely removed from the position of the magnetic medium 5. It is to be 
noted that the positional relationship between the rotary bodies 15', 15" 
and the magnetic medium 5 of the copy medium p, the strength of the 
permanent magnets, the number of magnets and the rotational speed of the 
rotary bodies are preselected so as to apply the necessary magnetic fields 
for magnetic transfer and erasure at the area of contact between the 
master medium and the copy medium. 
The rotary bodies 15, 15', 15" in the foregoing embodiments were 
illustrated as having eight pole pieces N and S in total exposed to the 
air. Taking an example, assuming that these rotary bodies are directly 
driven by an electric motor of 1500 RPM, the permanent magnets generate an 
alternating magnetic field of 100Hz (1500 RPM .times. 8 /60 sec .times. 
2). Permanent magnets formed from samarium-cobalt (Sm Co.sub.5), cobalt 
ferrite (CoFe.sub.2 O.sub.4), anisotropical barium-cobalt, barium ferrite 
(BaO.multidot.6Fe.sub.2 O.sub.3), Alnico or the like easily generate the 
required magnetic fields. For example, a permanent magnet produced from 
samarium-cobalt will have a field strength of 2,750 Gauss at the end 
surface of the pole piece, 1,700-2,000 Gauss at a distance of 0.5 mm from 
the end surface, 1,000-1,200 Gauss at a distance of 1.0 mm, and 250-300 
Gauss at a distance of 3.0 mm. Accordingly, this material can be used for 
the permanent magnets for the rotary bodies of the present invention, 
since it generates a magnetic field of sufficient strength as the magnetic 
transfer field and the erasing field for ordinary master media and copy 
media. It has been confirmed that the 100 Hz alternate magnetic field was 
sufficient for magnetic transfer from a master medium m to a copy medium 
p, both of which are being advanced at a velocity of 5 cm/sec. For 
erasure, it is generally preferable to use a higher frequency than the 
magnetic transfer field. This can be easily attained by increasing the 
number of the permanent magnets 16" supported by the rotary body 15" in 
the case of the embodiment in FIG. 4. 
Another embodiment of the present invention is illustrated in FIG. 5 in 
which elements or parts similar to those in FIG. 1 are indicated by the 
same reference numerals, a detailed explanation of which will be omitted. 
The feature of this embodiment resides in the fact that the transfer field 
and the erasing field are generated from a combination of at least one 
permanent magnet and at least one DC electromagnet. For the simplicity of 
explanation, this embodiment is described as comprising a rotary body 
consisting of a single bar permanent magnet having N and S poles plus a DC 
winding. More specifically, a rotary body 14"' comprising a permanent 
magnet is supported at 19 by the drive shaft 6. The rotary body 15"' is 
driven from the shaft 6 at a high rotational velocity in the direction 
indicated by 21 or 22 for generating a required alternate magnetic field 
at the contact area of the copy medium with the master medium. The rotary 
body 15"' is provided with a pair of coils or windings 22 and 23 which 
have a direction of winding to strengthen the magnetic field at the pole 
pieces N and S upon passage of a DC current. In other words, the magnetic 
field from the DC windings 22, 23 is superposed on the magnetic field 
generated by the permanent magnet and thus two types of magnetic field are 
generated in response to energization and deenergization of the DC 
windings 22 and 23. 
That is, when DC current is not passed through the windings, the alternate 
magnetic field generated by the pole pieces of the rotating permanent 
magnet or the rotary body 15"' has a field strength required for magnetic 
transfer of signals from the master medium m to the copy medium p. On the 
other hand, when the DC current is passed through the windings 22, 23, the 
magnetic field from the permanent magnet is strengthened by the DC 
magnetic field to provide a field strength required for magnetic erasure 
of the copy medium p or both the copy medium and the master medium p. 
Alternatively, the DC current to be applied to the DC windings may be 
reversed to weaken the magnetic field of the permanent magnet and the 
strength of the permanent magnet may be set at a higher value than in the 
above case. Thus, the magnetic field without passage of DC current is used 
for magnetic erasure while the magnetic field with passage of DC current 
is used for transfer field. 
According to the present embodiment, advantages are obtained that magnetic 
fields required for both magnetic transfer and erasure can be easily 
generated merely by superposing a small DC magnetic field on the magnetic 
field of relatively great strength, that there is no need of relying on 
any mechanical positioning or indexing means for the switching between the 
different types of magnetic fields, and that economical use of a DC 
electric source is attained. 
Although the embodiments of the present invention have been described with 
reference to the copy medium in the form of drum, it should be understood 
that the copy medium may be in the form of a tape. Further, the rotary 
type permanent magnet (or DC magnet) for generating magnetic transfer 
field and erasing field may be provided on the side of the pinch roller 
illustrated in the drawings, instead of installing it within the drum. 
Further, the magnetic field generating means may be separate for the 
magnetic transfer and the erasure. Also, the rotary bodies may be 
oscillated instead of being rotated. 
The present invention has been fully described in connection with preferred 
embodiments but it should be understood that a person skilled in the art 
can easily infer a modification or revision within the scope of the 
following claims.