Note: Descriptions are shown in the official language in which they were submitted.
:~t~ 2
The invention relates to a recording and/or playback apparatus for
a magnetic tape which cooperates with at least one scanning element (herein-
after referred to as a tape recorder), and more particularly to a tape
cassette recorder having a marking device for selectively applying index
marks which identify the positio~ of a magnetic head relative to the magnetic
tape in at least one marking zone of a marking carrier. Such tape recorders
have at least one marking element which is movable along the marking zone in
synchronism with the relative movement between the magnetic tape and the
head.
Such apparatus is for example described in U.S. Patent No. 2,218,5~2
and is in particular intended for dictation purposes. The user of such
apparatus can make optically identifiable marks in the form of punched-out
slits in paper marking-carriers by using the marking elements of the marking
device.
In addition, a number of other apparatus with marking devices and
marking carriers are known, by means of which index marks are made in accord-
ance with different methods, as by scribing on the marking carrier by the
removal of a layer of a special material from the marking carrier, by burning
in a mark on a thermographic marking carrier, and the like, for example,
see U.S. Patent No. 2,898,112. All these devices are more or less intricate
and expensive, demand a comparatively large amount of power for the applic-
ation of the marks and produce marks on the marking carrier which cannot be
erased, or are erasable only with great difficulty, so that a large number
of interchangeable marking carriers must be suppli~d with such apparatus.
A carrier with magnetically alignable particles for the storage
and visual read-out of information is also known from U.S. Pa~ent No.
3,683,382. This patent teaches that a visible image of a magnetic or elec-
trostatic force field can be obtained by impressing the field on a continuous
web or sheet of material having tiny liquid-containing chambers ha~ing
field-alignable particles in the liquid, and gives examples of use of such
a material for making visible graph lines on a strip chart recorder, x-y
recorder or the like.
The object of the invention is to provide an easily constructed
tape recorder apparatus by which index marks can be readily made and erased.
According to the invention, a strip having magnetically alignable
particles which store visible marks is mounted on an external surface of
tlle cassette in a tape recorder, and the marking device comp~ises a con-
trollable magnet for selectively magnetizing a marking element made of a
soft-magnetic material which conducts magnetic flux to the strip.
Broadly, therefore, the present invention comprises a magnetic
tape cassette recording system, comprising ~a) a tape casse~te comprising at
least one wall having an exterior surface; a planar marking strip affixed
to said exterior surface, said strip having at least one marking zone con-
taining magnetically alignable particles which store visually discernible
marks in response to application of a magne~ic field perpendicular to said
strip, said marks being magnetically erasable by applica~ion of a magnetic
field parallel to the plane of the strip; at least one hub rotatably mounted
in said cassette; and a length of magnetic tape wound on said hub, and ~b)
a tape recorder comprising a housing having a recessed portion in which said
cassette is placed, so arranged that said strip is visible; a magnetic head;
means for driving said tape past said head for recording or playing back
information on the tape; a marking element made of a soft magnetic material
and having a free end arranged to be visible; means for moving said marking
element in a given direction along the marking zone in synchronization with
movement of a tape past the head, said free end oriented perpendicular to
:
said strip; means for selectively magnetizing said marking element; and -
means for selectively applying a magnetic field parallel to the plane of the
strip of a cassette of the type described in paragraph (a).
An advantage of the invention is that the marking element need not ~;
exert mechanical force on the marking carrier. Further, *he process in the
marking carrier is magnetically reversible, so *hat marks can be magnetically
erased. As a result the user of a tape recorder according to the inven~ion
-3-
.~
~ '
~ J'~ 6 ~'~
need no longer have a large mlmber of marking carriers at his dispo~al
because the strip on the cassette is reusable.
Because of its particularly simple construction in a preferred
embodiment the controllable magnet is constituted by a permanent magnet
which is pivotable from a rest position towards the marking element. In a
recorder having two marking elements which are each associated with a
different marking zone of the marking carrier the permanent magnet can then
be pivoted from i~s rest position towards either the one or ~he other marking
element in an effective manner. Thus, marks can be made by simply pivoting
a permanent magnet, with no appreciable forces required.
A very simple construction is also obtained when in accordance
with the invention the controllable magnet is constituted by a coil mounted
on the marking element which coil can be energized electrically.
For erasing marks made on such a marking strip an erase device is
used which produces a magnetic field whose lines of force extend substantial-
ly in the plane of the strip, as described in the cited ~.S. Patent No.
3,683,682. In this respect in a preferred embodiment of an apparatus in
accordance with the invention a permanent magnetic and/or electromagnetic
erase device has a guide track for the passage of the marking strips through
the magnetic field. Thus, a marking strip can easily be erased before it
is used, by passing it for example manually along the guide track through
the magnetic field of the erase device, the guide track defining a suitable
location relative to the magnetic field. For utmost simplicity of operation
the guide track is constituted by a drop shaft with an entrance opening and
an exit opening.
The invention also relates to a cassette for magnetic tape compris-
ing a housing having at least one wall having an exterior surface; a planar
marking strip affixed to said exterior surface, said strip having at least
one marking zone containing magnetically alignable particles which store
30 visually discernible marks in response to application of a magnetic field
perpendicular to said-strip, said marks being magnetically erasable by
'"~
-4- ~
;.~
~ ' ~
~ 6 ~ ~
application of a magnetic field parallel to the plane of the strip; at least
one hub rotatably mounted in said cassette; and a length of magnetic tape
wound on said hub.
The special strip may simply be glued to the outer surface of the
top, or major flat cassette wall. Thus the casse~te and the marking carrier
form a single unit, whose two parts are jointly handled, so that there is
no risk that a marking carrier belonging to a specific cassette is mislaid
or is interchanged with other carriers. In particular when the cassette
in accordance with the invention is used as a dictation cassette this yields
the important advantage that a person transcribing dictation on the cassette
can directly read marks on the cassette, such as marks denoting the beginning
and end of the dictation, special instructions with respect to inserts in
the dictation etc.
Combining a magnetic tape cassette with a marking strip utilizing
magnetically alignable particles, furthermore, yields the advantage that when
the marks are made no mechanical forces are exerted on the marking carrier
` and the cassette
-:
-5-
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.
AP]IN.8~9ll
~ J~ 16-12-1976
respectively. ~s such a special marlcin~ carrier can be
erased~ it is ensured that the markiIlg carrier is re
usable,
As an alternati~e, the mar~ing carrier may
be disposed detachably on the wall of the cassette, so
that this carrier can simply be replaced, for example
in the event of damage during transport o~ the cassettes.
For this purpose the marking carrier is suitably placed
in a compartment provided in a wall of the cassette.
It may also be effective to attach marking carrier to
the cassette wall by at least a ~etachable cllp ~ich
can be fitted onto the cassette.
The invention will be described in more
detail with re~erence to the drawing which shows some
embodiments of the invention to which the invention is
not limitedc
. Figo 1 schematically shows those parts of
a recording and/or playback apparatus for a magnetic
tape accommodated ln a cassette~ which apparatus is to
be used in particular as a diotation apparatus, which
are essential for the invention.
Fig. 2 shows the apparatus of Fig. 1 in
` cross-section in accordance with the line II-II.
Fig. 3 is a cross-section of a second em-
bodiment of a cassette apparatus in accordance with thein~ention~
Fig. 4 shows a further embodiment of a cas~
sette apparatus in accordance with the in~ention9
- Fig. 5 shows an e~ample of a cassette with
magnetic tape which is suitable for use in a cassette
apparatus in accordance with the invention? and
Fig, 6 schematically shows a ~eel-to-reel
-6-
.
~PHN 8294
-'i A ~t^lrt~ ^J~p
16-12-1976
app~ra~ls in accordance with the i.nvention~ in which the
marking carrier is disposed on a stationary part o~ the
apparatus, the apparatus comprising a movable erase
device ~or the marking carrier.
In accordance with Figs. 1 and 2 a recording
and/or pla~back apparatus, to be us~d in par-ticular as
a dic'tation apparatus~ comprises a housing 1 with a
recessed portion 2 in which a cassette 4 is placed which
contains a magnetic tape 30 Drive spindles 5, 6 located
in the apparatus cooperate with winding hubs 7~ 8 in
,the cassette 4 in a conventional manner, so that the
'magnetic tape can beunwound ~rom one winding hub and
wound onto the o-ther winding hub. The magnetic tape 3
then runs along a narrow side 9 of the cassette in
which openings 10~ 11 are ~ormed~ through whi.ch scan-
ning elements extend into the apparatus, in the present
instance an erase head 12 and a recording~playback
head 13, which co-operate with the magnetic tape. The
: scanning elements are mounted on a base 14, which is
movable in the apparatus in the direction of the double
arrow 1~. Actuation means 16 which can be operated by
a control element ~not shown) engage with the base 14,
80 that the scanning element can be wi~hdrawn from the
cassette into a~!rest position, In the situation shown
in Fig. 1 and Fig9 2 the scanning elements are in
contact with the magnetic tape, whilst it is assumed
that magnetic tape has already been transported from the
hub 7 to the hub 8,
The apparatus is'pro~ided with a marking
` ~ 30 de~ice ~or a marking carrier on which marks can be made
in a selective manner~ which marks denote the relati~e
position o~ the scanning elements with respect to the
-7~
.
APIIN, 829l~
~ Y~ l6-12-1976
magl1etic tapc, so that ~or exam~le i~ the apparatus is
~sed for dictation purposes the beginning and the end of
the dictation or a correction can be identified. For this
purpose a marking carrier 19, 20 is provided optically
readable on each of the two walls 17, 18 of the cassette
4~ which walls constitute the ma~or surfaces~ said car-
rier consisting of a carrier with magnetically orienta-
table particles for the storage and optical read-out o~
a mark. In such a carrier the magnetically orientatable
particles~ depending on whether they have been exposed
to a magnetic field which extends in the plane of the
carrier or perpendicular to said plane, may assume two
different orientations, so that in one orientation they
reflect incident light and in the other orientation they
diffuse the incident light in the carrier material where
it is then absorbed so that -the carrier is bright in the
first instance and is dark in the second instance. In
the present example the marking carriers take the ~orm
- of strips which are glued in position parallel to the
longitudinal direction o~ the cassette in corresponding
re~esses formed in the walls 17, 18 of the cassette.
Each of the two marking carriers then corresponds to a
direction of transport of the magnetic tape from the
one winding hub to the other~ depending on the position
in which the cassette has been inserted into the appara
tus~ the marking carrier which ~aces the outside of the
apparatus and which is visible to the user being in the
operating condition. Thus, there is a fixed connection
between each cassette and marking carrier, so $hat they
cannot be mislaid or be interchanged9 for example during
transport of a cassette. Since with such special marking
carriers the magnetically stored and opticall~ readable
.
- ~,
APIIN.8294
~ 7~ 16-12-1976
marl~s can be erascd magneticall~ becatIse of the rever-
sible orientation proc~ss of tlle particles of the car-
rier, the marlcing carriers even in the case o~ frequent
use of a cassette, are always r~-usable, after erasure,
which will be described in more detail hereinafter.
For making marks on the relevant marking
carrier on the cassette a marking device 21 is pro~ided~
which comprises a magnetizing device 22 for two marking
elements 23, 24 which each correspond to a mark:ing zone
1 o 25 and 2 6 respectively on the marking carrier and which
can be moved along these marking zones in synchronis~ -~
with the relative movement between the magnetic tape 3
and the scanning elements 12, 13 which co-operate there
with. For this purpose, the marking device comprises a
stationary spindle 27 along which a block 28 of a non-
magnetizable material 9 in the present case a plastic
is movable. In this block the two marking elements 23 and
24 of a soft-magnetic material are embedded, the portions
299 30 and 31, 32 projecting from the block 28, The por-
tions 30 and 32 are guided in slots 33 and 34, which
are formed in a ridge 35 provided on the housing, and
they pass into bent pin-shaped free ends 36 and 37, which
terminate directly above the marking carrier 19 which
is located on the cassette 4. Furthermore, a semic r.cular
threaded portion 38 is formed in the block 28, which co-
operates with a threaded spindle 39 9 which is rotatably
Journalled in bearlngs 40, 41 mounted on $he base 14,
By moving the base 14 from the operating posi-tion to the
rest positîon; the scanning elements 12, 13 being with-
drawn from the cassette~ the connection between the
threaded spindle 39 and the block 28 is eliminated, in
which case a spring 43 which engages with the block 28
_9 .
y,r~, APITN . 829L~
16-12-1~76
i9 eliminated, in which case a spring 43 which engages
with the block 28 ~ia a belt 42~ moves said block into
a rest position which is defined by a stop 44 on the
housing 1~ after a projection 46 formed on *he base 14
and having a ramp 45 has released this rest position of
the block 28. In Fig. 1 this rest position is indicated
by dotted lines 47. On the threaded spindly 39 a disk
48 is fitted which co-operates with a slipping clutch
lining 499 which is mounted on a pulle~ 50, whlch disk-
is freely rotatablo on the threaded spindlc. From this
pulley 50 a belt 51 runs to an apparatus part, not
`~ shown, which rotates during transport of the magnetic
tape, for example a second puller which is mounted on
the winding spindle 6. In this way the block 28 together
with the marking elements 23 and 23 is moved along the
spindle 27 in synchronism with the relative movement
; between the magnetic tape and the scanning element, the
~ree ends 36, 37 of the marking elements covering the
corresponding marking zones 25 and 26 o~ the marking
carrier 19. With the aid of a scale 52 which is printed
OIl the marking carriers it is then also ~isible, in a
~imilar way as with a counter~ how much magnetic tape
lS contained on the winding hubs7 and 8 respectively.
The magnetizing de~ice 22 comprises a rod-
shaped axially magnetized permanent magnet 53 which is
~ounted on an arm 54 which is constituted by a projection
o~ a ring 55, which is plvotably Journalled around a
hollow cylindrical projection 56 on the klock 2B and
which is ooaxial uith the spindle 27. This ring 55
-~ 30 furthermore comprises a second projection in -the form
o~ an arm 57 with a fork-shaped end 58~ which includes
a bar 59 which at both ends is pivotabl~ journalled to
-10-
APIIN.8294
7~ 16--12-1976
the spindle 27 by meàns o* connecting port:ions 60 and 61
on the spindle 27, whilst furthermore a handle 62 is
connected to the portion 60. In this way, by tilting the
handle 62 and thus the bar 59, the arm 57 and the ring
55 as well as the arm 54 and the permanent magnet 53 is
pi~otable in any arbitrary position of the bloclc 28;
so that the permanent magnet can be made to engage either
with the projection 29 of the ma~k:ing elemen-t 23 or the
projection 31 of the marking element 24. A stop means
63 which co-operates with the bar 5.9, as is sho~ in
Figs. 1 and 2, defines a rest position of the actuation
device ~or the permanent magnet, in which position this
magnet is kept remote from the two projections 29 and 31
of the two marking elements
When the apparatus is put into operation the
; base 14 is in its rest position7 in which position the
scanning elements 129 13 disposed on it are wi~hdra~n
from the recess 2, the block 28 with the marking elements
23 and 24 then also being in the rest position, in which
said block~ as stated~ engages with the stop 44, In this
rest position of the block 28 the two marking elements,
: as shown in Fig, 1~ are disposed beside the recess 2, so
that a cassette 4 ~can be placed into the said recess
- unimpeded. Subsequently, the base 14 is moved into the
operating position, the scanning elements 12, 13 then
penetrating the cassette and engaging with the magnetic
tape. Simultaneously with this mo~ement o~ the base 14
the block 28 is mo~ed so far in the direction of the
arrow 64 via the ramp 45 formed on the projection 46
.
of said base,which ramp then engages with said block~
that the blook comes clear of the rampt after which~
: as the ba~e 14 mo~es on~ the connection between the
.
1~-12~1976
threadecl spindle 39 and the threaded porti.on 38 of the
block 28 is established. In this position o~ the block
28, indicated by the dotted lines 65 in Fig. 1~ the
marking elements 23, 24 have assumed their initial posi-
- 5 tion above the marking carrier 19. T~en the drive means
for the transport Or the magnetl.c tape from the hub 7
to the hub 8 is now s~itched on, steps having been
taken to ensure that, if necessary the tape is automatically
wound completely OlltO the winding hub r7~ tha block 28
with the marking elements 239 24 synchronously follows
the movement o~ the magnetic tape by means of the
threaded spindle 39 which is then also dri~en, the *ree
ends 36, 37 of the marking elements then covering the
; marking zones 25, 26 on the marking carrier.
If a specific point of the magne-tic tape in
respect of its position relative to the sc~nning element
is to be identified by means on a mark in the marking
zone 25 or 26, the lever 62 is pivoted so that the per-
manent magnet 53 is moved against the projection 29 of
the marking element 23 or the projection 31 of the
- marking element 24. As a result, the rele~ant marking
element is magnetized so that t~e magnetic field ~hich
emanates from the ~ree end 36 or 37 respecti~ely passes
through the marking carrier substantially at right
angles to the plane of the said carrier~ the magnetically
orientatable particles o~ this carrier in the underlying
area of the marking carrier being influenced in such a
way that they are re-oriented compared with their ori-
ginal orientation, so that at this point an optically
visible mark is obtained and is recorded. Thus, such a
mark can be made without mechanically loading any com-
: ponent~ neither the marking elements nor the marking
.
~ -12
,
~ APHN 8294
carrier~ L~y si.mply pi.voting a permanen-t m~gnet.
~ s the magn~tic orient~tion o~ the particles
of themarking carrier is re~ersible, such marks can also
be erased, which is ef:~ected with the aid o~ a magnetic
field~ which then extends substantiall~ in the plane o~
themarking carrier. In the simplest case marks can be
erased ~ith the aid of an axiallymagnetized rod magnQt~
which is mamlall~ passed over the marking carrier with
the circum~erential sur~ace transverse thereto. Thus,
- 10 such a marking carrier is re-usable 9 which is an essen-
tial ad~antage~ because it is no longer nccessary to
have a large number o~ interchangeable marking carriers
at one's disposal ~or such an apparatus. Another impor-
tant advantage is .~urthermore that those who have to
transcribe a dictation from such a cassette can directly
read the marks from the cassette, which marks denote .~or
example the beginning and end o~ a dictation, or special
nstructions relating to inserts in the dictation etc.
In th~ second embodiment of E`ig~ 3 the
marking carriers 19, 20 which contain the mag~etically
orientatable particles are each inserted in a compart-
. ment 66~ 67 ~ormed in the walls 17 and 18 of the cas-
sette 40 In the present case the two compartments each
have a window 68 and 69 respectively for opticall~ read-
ing the marking carrier. In the case that the compa~t-
ments are made o~ a transparent material~ such windows
may be dispensed with.
The marking device again comprises a block
28 which is movable along a stationar~ spindle 27 and
which co-operates with a threaded spindle 39 with a semi-
circular threaded portion 38, ~Jhich spindle is dri~en
in synchronism with the transport o~ the magnetic tape.
'' . .
-: ~13-
-
- - . . .
t~ AP~IN,8291~
16-12-1976
A U-shaped bracket 71, whose leg 70 is parallel to the
spindle 27, is pivotable in the apparatus and a spring
72 loads the part 70 of the bracket, which part runs in
a groove 73 of the block 28, in such a way that a COll-
nection between the threaded portion 38 and the threadedspindle 39 is guarante~d. As marking ~lement a hook-
shaped pin 74 of a so~t magnetic material is mounted
in the block 28, whose ~ree end 75 e~tends over the
marking carrier 19 on the cassette 4, With an actuating
element 76~ which acts on the bracket 71 via a rod 77
this bracket is pivotable against the action of the
spring 72; the block 28 -then also being pivoted about
the spindle 27 and the marking elemen-t 74 thus being
moved beyond the range of the cassette, as is indicated
by the dotted lines 78 in Fig. 3. Thus, the marking ele-
ment 74 does not impede the insertion or removalvof a
cassette into or from the apparatus.
The magnetizing device 22 for the marking
element 74 is constituted by a coil 79 provided on the
element, which via two slip contacts 80~ 81 makes elcc-
trical contact with two contact tracks 82~ 83 provided
in the apparatus, The two contact tracks are connected
to anenergizing circuit 84, whioh includes a switch 85
which can be closed upon actuation o~ an actuation ele-
ment 86~ When the switch 85 is closed current will flo~through the coil 79, independentl~ of the instantaneous
posltion of the block 289 so that the magnetic field
produced by the coil is passed from the marking element
74 *o the marking carrier 19 and passes through the plane
.
o~ said carrier substantially at right angles thereto~
which at the location of the marking carrier results in
- a re-orientation o~ the magnetically orientatable particles,
` ' . `
~ r~ ~ IIN 8~94
so that ~gain an opticàll~ visible mark is obtained and
is recorded.
The apparatus of Fig. 3 is provided with
an erase device 87 for the marking carrier.For this
purpose an axially magnetized rod magnet `89 whose axis
is substantiall~ parallel to the housing sur~ace is
fitted in a recess 88 ~ormed in the housing I of the
apparatus, for example in that said rod in the recess
88 is embedded in a plastic 90 Thus~; the magnet pro-
duces a magnetic field 9I which extends outside theapparatus, which field may be used as an erase field
for the marking carriers on the cassette. For erasure
a cassetta with marking carriers is passed through the
erase field by hand, in such a way that this field
passes through the plane of the marking carriers, For
defining the relevant paths to be followed by the mark-
ing carriers ~n conjunction with the cassette during
passage through the alternating field, a guide track for
a cassette is provided on the housing I above the per-
manent magnet 89, which track consists of a channel 92which is adapted to the cross-section of the cassette,
along whlch channel a cassette can be moved by hand in
the dlrection of the arrow 93, Thus~ the position of
the marking carriers 19 and 20 relative to the erase
field 91 is accurately defined, so that perfect erasure
.: .
is guaranteed. A cassette may also be moved automatically
along such a guide track.
In the embodiment of Fig. 4 the marking
carrier 19 which contains the magneticall~ orientatable
.
- 30 particles is mounted on a narrow side wall 94 of the
cassette 4~ preferably on that wall which faces the
narrow side 9 through which the scanning elements ~ r the
'
-15-
'- ' '
~PIIN.8294
~ 12-1976
magnetic t~pe cnter.`:[n this c~se the cassette 4 is placed
in a sha~t-shaped cassette conlainer 959 which is pivoted
to the apparat~s~ whos~ wall 96 which extends parallel
to the marking carrier 19 has an opening 97 for the pas-
sage of the two free ends of the two marking elemen-ts Z3,
24. The two marking elements each act on one half of
the marking carrier, so that when the caæsette is turned
over9 they cover the other half of the marking carrier.
In order to make the marking carrier visible to the user
o~ the apparatus, the housing I has an opening 98 below
which a mirror 99 is sui-tably arranged. If d~sired, an
illuminating device may be providedO
In this apparatus the erasing device 87
comprises a flat coil 100 which can be energized
electrically so as to produce the magnetic alternating
field through which a cassette can be passed together
with the marking carrier, for which purpose again a
guide track is provided which in this case takes the
~orm of a shaft 101 which is adapted to the cross-section
o~ the cassette, which has an entrance opening 102 and
an exit opening l03~ and which extends through the ~lat
coil 100. For erasing a marking carrier the relevant
cassette is moved in the direction o~ the arrow 104
into the entrance opening 102, after which the cassette
falls through the shaftand remains at the bottom 105
thereof in front of the exit 103~ from which the cassette
can be removed by hand. The marking carrier has then
passed through the erase field in such a way that the
erase field passes through the carrier in the plane of
the carrier, so that the marks recorded on the marking
.
carrier are erased.
In an embodiment o~ a cassette shown in
-16-
~ -
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f~ Ap~IN.82gll
16-12-1976
Fig, 5 a marking carrier is secured to each of the two
~alls whlch constitute the major sur~aces with the aid
of a U-shaped cliplO6 of a transparent material which
partly covers the two walls. In ~ig. 5 the wall 17 and
the marking carrier l9 are then visible~ For fitting the
clip onto the cassette a snap connection is provided which
consists of a projection 108 ~ormed at the base 107 o~
the U-shaped clip, which projection en~ages with a recess
109 ~hich is ~ormed in a narrow side wall 94 o~ the cas-
sette, This enables the marking carrier to be exchangedin a simple way, the sida walls o~ the clip also ~orming
a protect:ion ~or the marking carrier. Such a cassette
together with the marking carrier can also be passed
through an erase device. However~ it is alternatively
; 15 possible to pass only the marking carriers through an
erase de~ice, Furthermore, it ~s possible in the case
o~ a cassette which is located in the apparatus in the
operating position, to erase the mar~ing carriers on this
cassette with the aid of an erase device which is
movably disposed~on the apparatus.
In the embodiment o~ Fig. 6 the marking
carrier 19 with the magnetically orientatable particles
is secured to a bracket 110 of a non~magnetizable ma-
terial which is mounted on the apparatus, which bracket
is situated underneath a window 111 formed i~ the appa-
- ratus housing 1. Associated with the marking carrier
is a marking element 23 which is movable in synchronism
with the relative movement between the magnetic tape
and the scanning elements, which marking element can be
magneti~ed ~or the purpose o~ ma~ing in a manner not
shown.
` For erasing marks a movable erase device 112
:. . .
, . . , , -
. . .. . . .
API-IN 8294
~ t~. 16 12-1976
is prov:ided, whi ch C omprises a ~lat coil -113, which can.
be energizcd electrically and ~hich extends around the
bracket 110~ and a U-shaped permanent magnet 114, which
extends around the coil, which -two parts 113, 114 are
mounted or a base 115. Said base 115 comprises a handle
116 which projects through a slot 117 which is formed in
the apparatus housing and which extends parallel to the
bracket 1l0. Bymoving the handl.e 116 along the slot 117
the erase device can be moved over the marking carrier
and underneath the marking element 23, Thus, the marking
carrier is ~ery ef~ectively erased by two mutually per-
pendicular magnetic fields which extend in the plane o~
the marking carrier9 namely by the ~ield of the flat
coil and by that of the permanent magnet, through a
corresponding reorientation o~ the magnetic particles.
Further modi~ications to the embodimerts
described hereinbefore are possible within the scope of
the in~ention. In this respect it is to be noted that
the marking carrier may-also ha~e a shape other -than
that of a strip, for example a rourd shape with concen~
~: tric marking zones.
'
. '
18
'. ' ' ': -" ,
