Production of prerecorded tape cassettes

What is claimed is:

1. A method of recording magnetic video tape for subsequent loading into cassettes, comprising:

transporting said video tape in a first tape transport direction,

recording programme signals representing programme material along sections of tape while being transported in said first tape transport direction,

recording data signals representing data related to said programme material along the synchronisation track of the said video tape immediately after recording the programme material to which said data signals relate, said data signals being recorded between successive said programme signals while said tape is being transported in said first tape transport direction, said data signals being in the form of asynchronous modulation of the regularly occurring video synchronisation signal of the video synchronisation track such that when said tape is transported in a tape transport direction opposite said first tape transport direction said data signals are detectable by transducer means to generate signals representative of said programme material recorded on the immediately following section of tape.

2. The method of claim 1, wherein said programme signals and said data signals are recorded onto said magnetic tape by transporting said tape past respective recording heads at a recording station and applying electrical signals to said recording heads whereby to generate varying magnetic patterns on said tape.

3. The method of claim 1, wherein:

said programme signals are recorded onto said magnetic tape by transporting said tape and a tape carrying a mirror image master recording of the programme material through a recording station having means for pressing said two tapes into close contact in an applied magnetic field whereby to induce a reverse reproduction of the magnetic pattern on said master tape to be formed on said magnetic tape, and

said data signals are recorded onto said magnetic tape by transporting said tape past a recording head and applying electrical signals thereto.

4. The method of claim 1, wherein said data signals are recorded on said magnetic tape in a digitally encoded recording pattern.

5. The method of claim 1, wherein said data signals are recordeD as variable length absences in said video synchronization signal on said video sync track.

6. The method of claim 1, wherein said data signals are generated by a computer connected to signal recording means.

7. The method of claim 6, wherein said programme signals are recorded onto said tape and the end of said programme signals are detected to trigger the generation of said data signals, and wherein said data signals are recorded onto said tape on a portion of said tape following that on which said programme signals are recorded when said tape is transported in said first direction of tape transport.

8. The method of claim 1, wherein said data signals comprise at least data information signifying the identity of said programme.

9. The method of claim 1, wherein said data signals comprise at least data information representing the length of said tape occupied by said programme signals to which it relates.

10. The method of claim 1 further including the step of recording further coded data signals onto said tape signifying the number of individual programmes recorded on said tape between a leading end of said tape and the location of said further data signals.

11. A method of producing a cassette of pre-recorded magnetic tape, comprising the steps of:

preparing a reel of magnetic tape recorded with a plurality of sets of programme signals each set followed by a recording of data signals representative of at least one characteristic of a set of preceding programme signals recorded on said tape,

loading a length of said magnetic tape cut from said reel into a cassette so that said cassette contains tape recorded with at least one set of programme signals, and

machine reading the recorded data associated with a programme recorded on said length of tape, and

representing data machine-read from said tape as a visual display.

12. The method of claim 11, wherein said visual display representing said code is formed on said cassette shell.

13. The method of claim 11, wherein said visual display representing said code is formed as a remote display generated by remote display means.

14. The method claim of 11 wherein said at least one characteristic of a set of program signals recorded on said tape is one of:

the program identity,

the program history,

the program composition and

a program duration in units of time.

15. A method of producing cassettes of magnetic tape recorded with programme material, comprising the steps of:

preparing a reel of tape having a plurality of lengths recorded with programme signals intercalated with recorded data signals by transporting said video tape in a first tape transport direction, recording programme signals representing programme material along sections of tape while being transported in said first tape transport direction,

recording data signals representing data related to said programme material immediately after recording the programme material to which said data signals relate, with said data signals being recorded between successive said programme signals while said tape is being transported in said first tape transport direction, said data signals being in a form such that when said tape is transported in a tape transport direction opposite said first tape transport direction said data signals are detectable by transducer means to generate signals representative of said programme material recorded on the immediately following section of tape,

transferring said reel of tape to a cassette loader having a transducer responsive to said recorded data signals,

transporting tape into a cassette shell on said cassette loader past said transducer,

detecting said data signals with said transducer, and controlling the operation of said tape transport in dependence on signals generated by said transducer.

16. The method of claim 15, wherein said means for forming visible indicia comprise a label printer and said method includes the step of

applying a label printed with indicia corresponding to said data signals onto said cassette shell one of during winding of said length of tape recorded with said programme material to which said data signals relate and immediately after winding said length of tape.

17. The method of claim 15, wherein said means for forming visible indicia comprise

means for directly marking said cassette shell being loaded one of during winding of said tape and immediately thereafter.

18. The method of claim 17, wherein said step of directly marking said cassette shell comprises engraving indicia on said cassette shell.

19. The method of claim 17, wherein said data signals detected by said transducer include a data signal representing the length of tape occupied by programme material to which said data signals relate, and said method includes the step of:

storing said data length signal after detection thereof,

generating signals representing the displacement of said tape during winding thereof,

comparing said displacement-representative signals with said stored signals and,

initiating deceleration of said tape transport means when a predetermined difference is detected therebetween.

20. The method of claim 15, wherein said data signals include information identifying the recording means by which the said programme material is recorded onto said tape.

21. The method of claim 15, further including the step of:

recording a cue signal on said tape immediately prior to recording a length of tape with programme material and,

detecting said cue signal as tape is subsequently wound into a cassette whereby to control stopping of said tape transport means.

22. The method of claim 15, further including the step of controlling means for forming visible indicia representing the identity of the programme material recorded on said tape in dependence on signals generated by said transducer.

23. The method of claim 15, wherein said programme signals and said data signals are recorded onto said magnetic tape by transporting said tape past respective recording heads at a recording station and applying electrical signals to said recording heads whereby to generate varying magnetic patterns on said tape.

24. The method of claim 15, wherein:

said programme signals are recorded onto said magnetic tape by transporting said tape and a tape carrying a mirror image master recording of the programme material through a recording station having means for pressing said two tapes into close contact in an applied magnetic field whereby to induce a reverse reproduction of the magnetic pattern on said master tape to be formed on said magnetic tape, and

said data signals are recorded onto said magnetic tape by transporting said tape past a recording head and applying electrical signals thereto.

25. The method of claim 15, wherein said data signals are recorded on said magnetic tape in a digitally encoded recording pattern.

26. The method of claim 15, wherein said data signals are recorded as variable length absences in said video synchronization signal on said video sync track.

27. The method of claim 15, wherein said data signals are generated by a computer connected to signal recording means.

28. The method of claim 15, wherein said data signals comprise at least data informatioin signifying the identity of said programme.

29. The method of claim 15, wherein said data signals comprise at least data information representing the length of said tape occupied by said programme signals to which it relates.

30. The method of claim 15, further including the step of recording further coded data signals onto said tape signifying the number of individual programmes recorded on said tape between a leading end of said tape and the location of said further data signals.

31. A method of producing recorded magnetic tape for subsequent loading into cassettes, comprising transporting said tape in a first tape transport direction, recording programme signals representing programme material along sections of tape while being transported in said first tape transport direction,

recording data signals representing data related to said programme material immediately after recording the programme material to which said data signals relate, with said data signals being recorded between successive said programme signals while said tape is being transported in said first tape transport direction, said data signals being in a form such that when said tape is transported in a tape transport direction opposite said first tape transport direction said data signals are detectable by transducer means to generate signals representative of said programme material recorded on the immediately following section of tape, said data signals including information identifying the recording means by which said programme material is recorded onto said tape, and

controlling the performance of a product sampling procedure on the basis of said recorded data signals, said product sampling procedure comprising the steps of:

testing the quality of a sample of said recorded programme material, determining the history of said sample from a display of information represented by said recorded data signals at least in the event of unsatisfactory results from said testing, and

directing a subsequent investigation into materials and equipment used in the production of said sample under test on the basis of said displayed information.

32. Apparatus for producing cassette or recorded tape comprising:

means for generating program signals,

recording transducer means,

means for feeding said program signals to said recording transducer means,

means for generating data signals,

means for supplying said data signals to said recording transducer means,

tape transport means for transporting magnetic tape to be recorded past said recording transducer means, and control means connected to said program signal generator and to said at a signal generator and operative to control energisation of said transducer means whereby to recorded data signals and related program signals in sequence along said tape,

means for winding said tape onto open spools after recording,

a transducer sensitive to said recorded data signals and operative to generate electrical signals in response thereto,

cassette loading means having a

cassette loading station,

a cassette rack operable to deliver empty cassettes to said cassette loading station, and

cassette identification means operative in response to said electrical signals generated by the said transducer to provide visible indicia representative of the program identified by the said data signal.

33. The apparatus of claim 32, wherein said recording transducer means comprise a programme transducer to which said programme signals are fed by said means for feeding programme signals, and a data transducer separate from said programme transducer to which said data signals are supplied by said means for supplying data signals, said two transducers being spaced along the path of said magnetic tape.

34. The apparatus of claim 33, wherein said data transducer is adapted to record along the video sync track of video tape.

35. The apparatus of claim 32, including means for mounting a non-cassette supply spool and a non-cassette take-up spool to the apparatus for rotation about a common axis in parallel juxtaposed planes of rotation, and

means for effecting driven rotation of said spools so as in use to provide discharge of unrecorded use tape from said supply spool and take-up of recorded tape by said take-up spool.

36. The apparatus of claim 32, wherein said cassette identification means comprises a label printer operative to print labels bearing indicia determined by said data signals, and there are further provided means for applying said labels to said cassette shells before being ejected from said cassette loading means.

37. The apparatus of claim 36, wherein said label printer is operative to produce indicia in the form of machine readable bar codes on labels to be applied to said cassettes.

38. The apparatus of claim 37, wherein there are further provided means for reading said bar code labels and directing cassettes to one of a plurality of label application stations at which preliminarily prepared printed labels from a stack thereof are applied to said cassettes.

39. The apparatus of claim 32, wherein said cassette loading means further includes a control circuit operative to control said spindle drive means in accordance with signals received from said transducer.

Description Submit all comments and votes

This invention relates to a method and apparatus for recording and loading magnetic tape cassettes.

As used in this specification the term "magnetic tape cassette" will be understood to relate to an assembly comprising an enclosing casing or shell housing two spools wound with a length of magnetic tape. Such cassettes are widely known for use with audio or video equipment and also as a recording store of data for computers. Regardless of its intended function the magnetic tape carried on the spools is of substantially the same form, comprising a flexible supporting substrate on one face of which there is formed an oxide layer exhibiting specific magnetic properties. Currently, the most well known types of cassettes are the Phillips "compact" cassette for audio and data information and the JVC "VHS" cassette for video information.

Magnetic tape for use in such cassettes is manufactured in rolls many thousands of metres long sufficient to fill very many cassettes. This tape is wound into the plastic housings or shells to form cassettes using a special machine known as a cassette loader. The information to be stored on the magnetic tape may be recorded after the tape has been loaded into the cassettes ("in-cassette duplication") or may be recorded before loading into the cassettes ("reel-to-reel duplication"). If the tape is recorded before being loaded into cassettes this is usually achieved by recording the same programme repeatedly onto a length of tape sufficient to fill several cassettes, and then loading a length of the tape containing one programme into each of several cassettes sequentially. In order to ensure that the length of tape loaded into a cassette contains the whole of a programme (and in this context, the term "programme" will be understood to mean a complete set of use signals, be they video or audio signals for entertainment or education purposes, or data signals for operating a computer or serving as the working basis for computer operation) it is necessary to leave a certain unrecorded length of tape between the end of a recorded programme and the commencement of the next adjacent recorded programme. It has also been known to record identifiable "cue tones" at the beginning or end (or both) of the programme material so that the physical break in the tape can with certainty be made in such a way that it does not impinge on the recorded programme material. In this way, the loader can detect the correct point to complete one cassette and start the next.

In audio cassette production (and some data cassettes), programme material can be recorded at high speed in reel-to-reel recording machines having large-diameter reels of use tape, special machines having been developed for this purpose. Typically, magnetic use tape equivalent to about 30 to 40 C 60 cassettes is recorded in this way from a length of "master" tape on which the programme information has been recorded with high fidelity.

This arrangement inevitably means that audio cassette reel-to-reel recording equipment is somewhat bulky, a recording deck having a relatively large surface area in order to accommodate the supply spool and take-up spool in side-by-side relationship. In practice, this is a relatively minor disadvantage in a conventional audio context because of the high speed at which recording is effected. This is possible with audio signals because of their comparatively narrow bandwidth. Recording can thus be carried out at a very high speed without loss of recording quality. For example, recording may be carried out at from 32 to 128 times playback speed. This enables highly productive audio cassette recording operations to be set up with relatively few copier machines so that the size of the machines themselves is at least tolerable.

In video recording, however, the recorded signals are of much higher bandwidth so that recording of such signals cannot be carried out at high speed without serious loss of recording quality. Even a recording speed 50 per cent higher than playback speed will normally result in an unacceptable reduction in quality and in most cases the recording speed has to be equal to the retrieval or playback speed. Because of this relatively slow speed of recording, many more copier machines are needed for video copying than for audio recording; indeed it is not unknown for a single establishment to have several thousands of copiers operating at the same time. Video copiers having the same size as open reel audio copiers would require about 400 per cent more space than an in-cassette copier and this is totally unacceptable. The same applies to high bandwidth audio copying e.g. R-DAT and S-DAT format. Although there are the above described differences between the treatment of audio and video tape due to differences in the nature of the signals there is in practice no difference in the magnetic tape itself except that tape for video signals is wider in order to accommodate the inclined recording stripes recorded by the rotating tape heads of a video recorder or playback machine. For the above reasons, in-cassette copying of video tapes remained customary practice for many years. However, the method has always been regarded as unsatisfactory for a number of reasons. First, the process is labour intensive due to the requirement to change the cassette after each recording had been completed. Secondly, the mechanisms which handle the slave cassettes in the players are inherently complex and sufficiently prone to unreliable performance that they can give significant practical problems after a prolonged period of heavy use. Thirdly, since the players have to start and stop between recording each cassette, and since each cassette contains tape which may have come from different reels of varying quality, it is necessary to sample each one after the recording has been completed in order to ensure the recording process has proceeded correctly.

Finding a solution to the problems of existing video copiers has been the subject of much activity in the industry and machines which eliminate many of the above-enumerated problems are now available.

The Sony Sprinter system, for example, passes a master tape carrying a "mirror image" of the magnetic recording patterns in contact with a slave tape through a recording station at which the two tapes are pressed together with a magnetic field applied so that the mirror image magnetic pattern is transferred reversely. The two tapes are stationary relative to each other and thus both may be transported at high speed through the recording station. This speed facility reduces the space requirements for a particular production level relative to the large space which would otherwise be needed. Quality recording requires a very strongly recorded master tape which is difficult to produce, production requiring specialist expensive recording techniques, and the print-through recorder is also itself expensive to produce since video copiers for commercial cassette production operations represent a small market, whose supply involves the economic disadvantages of small scale production operations. However, quality of recording is obtainable at high speed and in a labour-saving manner, thus making the machine commercially desirable and used increasingly. The Tape Automation ETD system comprises a recording head for recording the programme material onto use tape, and a pair of independantly operative motors (for example stepping motors) for effecting rim drive of each of two non-cassette (open) spools which are in use mounted to the apparatus for rotation about a common axis in parallel juxtaposed planes of rotation, one such spool serving as a supply spool which in use discharges use tape to the recording head and the other such spool serving as a take-up spool to take up recorded tape issuing from the recording head. The stepper motors are operable subject to control means for detecting changes in speed of tape supply and take-up whereby the relative speed of driven rotation of the spools can be adjusted to equalize tape supply to and tape take-up from the recording head. The space requirements of the machine are no more than about 25 per cent more than for conventional in-cassette mass copiers, an acceptable increase in practice. The spools of tape used in this system are very large diameter unbraced spools, that is the tape is wound on a core without the guiding discs conventionally used on open reels. By winding the tape at the correct high tension such open spools can be made hard and effectively self-supporting. They are known as "pancake" spools for obvious reasons.

Although the above machines largely deal with many of the above-outlined problems, without loss of recording quality, they do impose very severe logistic and organisational problems in a manufacturing operation. In order to gain maximum benefit when using the pancake spools it is desirable to record the whole length of tape on a spool before removing it for winding. This is necessary in order to maintain an adequately light and sufficiently constant winding tension to keep the spool in shape. This can involve up to 48 hours between pancake spool changes. However, other constraints such as the ratio of playback machines (producing the recording signal from a master cassette) to video loaders and the average batch size required, mean that in order to fill a whole pancake spool with recorded programme material, it is sometimes necessary to record different programmes at different points along the length of tape on the pancake spool. For example, the situation may be as follows:

______________________________________ Ratio of playback machines to 500:1 recording machines Average programme length 90 minutes Average batch required 1000 Length of tape in each pancake spool 4000 m Programmes/pancake spool 29 approx ______________________________________

It will be appreciated that all 500 recording machines will record the same programme material so that to produce a batch of 1000 will require a given programme to be played only twice by the master playback machine and recorded on two sucessive lengths of each spool. Since each pancake spool can record 29 programmes each will on average contain 14 or 15 different programmes each recorded twice. It will be appreciated that this situation, after only a short period of cassette winding, results in a number and variety of recorded cassettes such that unacceptable levels of operator supervision and intervention are called for if uncertainty as to the identity of programme material recorded on the various individual cassettes (which all appear visually identical from the outside) is to be avoided, and indeed if winding operations are to be conducted efficiently at all.

In the case of the Sony Springer system, each of, for example, ten pancake spools is recorded from the same programme material. However it is still very easy to lose track of the recording programme, which can lead to problems of identification similar to those just described. These problems often result in the necessity to play back each of a large number of recorded cassettes in order to establish what has been recorded on them.

The technical problem to which the present invention relates, therefore, is that of unambiguously and automatically identifying the programme material recorded on a length of tape to enable the programme content of a cassette containing such tape to be identified without the need to play back the tape.

According to one aspect of the invention, there is provided a method of recording magnetic tape for subsequent loading into cassettes, in which between signals representing the programme material recorded along sections of the tape there are recorded signals representing data related to and/or identifying the programme material and which, upon playback of the tape act to control a cassette loading machine and/or apparatus such as a label printer associated therewith.

Conveniently, signals representing the programme material and the data are recorded onto the magnetic tape by transporting the tape past a recording head or transducer at a recording station and in any event the programme material is preferably recorded from a master recording made on a recording medium (e.g. a master cassette) on which only the programme material is recorded (although, in fact, some of the data may also be recorded on the master). Alternatively, a master may first be sub-mastered to provide one or a plurality of sub-master recordings each used to record part of a very large number of programme copies onto magnetic tape on open or pancake spools, each sub-master having data encoded thereon to identify it as distinct from its parent and other sub-master(s).

Alternatively, the programme material may be recorded onto magnetic tape by transporting the said magnetic tape and a tape carrying a master recording of the programme material through a recording station including means for pressing the two tapes into close contact in an applied magnetic field to induce magnetic "print-through" of the recorded signal from the master recording tape onto the use tape.

In preferred embodiments of the invention, the magnetic tape is recorded with the programme material and data by transporting it through the recording station from an open supply spool to an open take-up spool.

According to a second aspect of the invention, there is provided a method of producing cassettes of magnetic tape recorded with programme material, comprising the steps of preparing a reel of tape having a plurality of lengths recorded with programme material intercalated with recorded signals representing data, transferring the reel to a cassette loader having a transducer responsive to the said recorded data signals, transporting tape into a cassette past the said transducer, controlling the operation of the tape transport in dependence on signals generated by the said transducer, and further controlling means for forming visible indicia representing the identity of the programme material recorded on the tape for application to the shell of the cassette.

The means for forming the visible indicia may comprise a label printer and the method may then include the step of automatically applying a label printed with indicia corresponding to the said data signals onto the shell of the cassette during winding of the length of tape recorded with the programme material to which the data relates or immediately thereafter.

In one embodiment the said means for forming visible indicia comprise means for directly marking or engraving the shell of the cassette being loaded during winding of the tape or immediately thereafter.

The data signals detected by the said transducer may include data representing the length of tape occupied by programme material to which the data relates, and the method includes the step of storing the data length signal after detection thereof, generating signals representing the displacement of tape during winding thereof, comparing the said displacement-representative signals with the said stored signals and initiating deceleration of the tape transport when there is a predetermined difference therebetween. The present invention also comprehends magnetic tape recorded along successive lengths thereof with first signals representing programme material and second signals representing data indentifying the recorded programme material and/or one or more characteristics of the recorded tape and/or its production, the said second signals acting to control the operation of a cassette loader and/or associated apparatus upon detection thereof by a transducer sensitive to the magnetic recording on the tape.

Preferably the said first signals are television signals and the said second signals are recorded on the tape in pulse code form.

These pulse code signals are preferably recorded on the tape as pulse width modulation of the signal recorded on the sync track of the video recording.

According to a further aspect, the present invention provides apparatus for producing recorded magnetic tape comprises means for generating programme signals, recording transducer means to which the said programme signals are fed, means for generating data signals to be supplied to the said recording transducer means, tape transport means for transporting the magnetic tape to be recorded past the said recording transducer means, and control means connected to the said programme signal generator and the said data signal generator and operative to control energization of the transducer means such that data signals and related programme signals are recorded in sequence along the tape.

The said recording transducer means may comprise a simple recording transducer or two separate transducers spaced along the path of the magnetic tape, one for recording signals representing programme material and one for recording signals representing data.

In a further aspect of the invention there is provided apparatus for producing cassettes of recorded magnetic tape comprising apparatus as defined above for producing successive recordings of programme material and data onto a length of magnetic tape, means for winding the tape onto open spools after recording, a transducer sensitive to the recorded data signals and operative to generate electrical control signals in response thereto, a cassette loader having a drive spindle engageable with a spool of a cassette to be loaded, drive means for the spindle, a control circuit operative to control the spindle drive means in accordance with electrical control signals received from the said sensor, and cassette identification means operative to provide visible indicia representative of the programme identified by the data signal.

In the preferred embodiment of the invention the said cassette identification means comprises a label printer operative to print labels bearing indicia determined by the said data signals, and there are further provided means for applying the labels to cassette shells before being ejected from the cassette loader.

The label printer may operate to produce indicia in the form of machine readable bar codes on the labels to be applied to the cassettes, in which case there are preferably provided means for reading the bar code labels and directing the cassettes to one of a plurality of label application stations at which preliminarily prepared labels from a stack thereof are applied to the cassettes. Alternatively, the bar codes are read by means which directs the cassettes to one of a plurality of packing stations or the bar codes are read and the cassettes sorted and directed to storage. Of course, read could be effected at a station and label selection effected thereat.

More generally, of course, the invention can be considered as a system for encoding serial binary data by asynchronous modulation of a regularly occurring event signal, in which the event signal is interrupted to encode the binary data and decoding of the interrupted event signal to regenerate the binary data is effected by determining the length of successive periods in which the event signal is interrupted and uninterrupted respectively.

The present invention can thus be considered to include a system for recording serial binary data onto a magnetic tape in the presence of a regular signal recorded thereon, in which the binary data is recorded as asynchronous interruptions of the regular signal. In this latter case, then, the regular signal is the synchronisation control signal recorded along the edge of a video tape and the interruptions are formed either by selective erasure of a previously recorded synchronisation control signal or by selective inhibition of the recording transducer by which the synchronisation control signal is recorded, and selective inhibition of the recording transducer may be effected by short-circuiting the recording transducer during the intervals for which the synchronisation control signal is to be interrupted.

One embodiment of the present invention will now be more particularly described, by way of example, with reference to the accompanying drawings, in which:

FIG. 1 is a diagram schematically showing apparatus for the production of recorded magnetic tape formed as an embodiment of the invention;

FIG. 2 is another diagram schematically illustrating a machine for producing recorded cassettes of magnetic tape from open spools or pancake reels of tape produced by the apparatus of FIG. 1;

FIG. 3 is a diagram illustrating a length of magnetic tape recorded with video programme material data;

FIG. 4 is a diagram representing, on an enlarged scale, a part of the magnetic tape of FIG. 3 with a schematic indication of the signals recorded thereon;

FIG. 5 is a schematic representation of a typical video synchronisation signal as recorded on or read from a magnetic video tape; and

FIG. 6 illustrates an alternative reel mounting arrangement.

Referring now to FIG. 1, magnetic tape is recorded by a programme duplication assembly comprising a master playback machine 11, a main recording controller 12 having a keyboard 13 for inputting information, and a bank of tape recorders for recording the video output of the master playback machine 11 and the data output of the main recording controller 12. As can be seen in FIG. 1 the slave tape recorders, which are identified with the reference numeral 14.sub.1 to 14.sub.n (where n, as mentioned above, may typically be 500 or in some cases may be 1000 or more) are equipped with drive means for carrying large open spools or pancake reels 15 from which tape is drawn over a capstan past two spaced recording heads 16, 17 onto a further open spool or pancake reel 18. The master playback machine is a conventional high quality video recorder, of the type generally available for domestic or professional use, modified so that video signals from a master programme cassette are output not to a VDU but to a programme output line 19 leading to the recording heads 16 of the recording machine 14.sub.i to 14.sub.n in parallel. The recording machines may have a construction and operation as described and illustrated in our co-pending U.S. patent application Ser. No. 092,327. As mentioned above, the bank of recorders 14 may comprise several hundred such recorders all receiving the same video signals derived from the master playback machine and the master cassette run thereon. Typically, about 500 recorders may be present in the bank. Each of the recording heads 17 is connected to a line 20 on which are applied data signals from the main recording controller 12, which in this embodiment comprises a suitably programmed interface computer. The computer also has a control output line 21 for conveying signals for controlling the production of "local" information derived directly from the individual recorders 14, such as a recorder identification code, which is thus recorded at appropriate points along the tape as controlled by the interface computer: this latter is also connected directly to the master playback machine 11 by a line 22 for the purpose of detecting the beginning and end of the programme material and for monitoring and/or controlling a pause period while the playback machine 11 rewinds for a subsequent run or while the cassette is replaced with another containing the same or a different program. In FIG. 1 a recording machine 14.sub.i is shown with an alternative construction for recording by the so-called mirror image technique used in the Sony Sprinter device described hereinabove. In the recording machine 14.sub.i a master tape 9 recorded with a mirror image signal is pressed into close contact with the recording tape at a recording station 10.

The interface computer 12 links the master playback machine 11 to the bank of recorders 14 and controls each production run on the basis of a production plan input to the computer via the keyboard 13 before the run is started (or afterwards and prior to playback of the master cassette to the end of the first master programme). Once a production run is complete, the computer prompts manual loading of the next master cassette and recycles. The signal control line 20 transmits global information output of the interface computer 12 to each recorder 14 in the recorder bank, the second line 21 being used to transmit trigger signals as discussed above.

Turning now to FIG. 2, the cassette loading station comprises at least one cassette loader generally indicated 30, which in this embodiment is of the type described and illustrated in our co-pending U.S. patent application Ser. No. 890,078. The loader 30 is one of a plurality of such loaders the number of which will depend entirely on the number of recorders 14 in the bank of recorders, but due to the much faster speed of loading as compared to recording, the number of loaders 30 will be much less than the number of recorders 14 (typically one loader will be capable of loading the collective output of about 50 recorders). The loader 30 is adapted to receive an open spool or pancake reel 18 taken from a recorder 14 after having been recorded with a sequence of programme material and data signals in alternation in a pattern which will be more particularly described in relation to FIG. 3. This will include information for identifying the programme material recorded on the tape wound into the cassette and in practice certain other information. The data also includes an index "mark" or "cue tones" signifying one end of one set of signals representing programme material and the data signals.

Before proceeding to a detailed description of the loading station in FIG. 2, the format of the recording on the tape wound on the open spool or pancake reel 18 will be discussed.

First, it will be appreciated that because of the relatively large number of recorders 14 all receiving signals from the master playback machine 11, it is possible to produce a large number of copies of an original master tape relatively quickly. For example, by playing the tape in the master playback machine 11 only twice there will have been produ