EP0072369B1 - Steel band printer with automatic identification of the printing band - Google Patents

Description

The invention relates to a rotating, interchangeable type carrier for impact printers with scannable timer markings assigned to the characters and with a scannable marker for determining the start of control processes for the character output.

The invention relates in particular to steel band printers.

• a) die Anordnung der Zeichen auf dem Band kennt (bzw. wenn die elektronische Abbildung (EBCDIC- oder ASCII-Code-Tabelle des Typensatzes) des Bandes in dem Druckersystem bekannt ist) und
• b) wenn der Zählvorgang bei einem bestimmten Punkt auf dem Band gestartet wird. Dieser Punkt sei im folgenden Startmarkierung genannt.

Such steel tape printers are e.g. B. became known through the model IBM 3262. They use all-round type bands on which the characters and the associated timer stamps are etched out. The timing marks can be scanned, as described later in connection with FIG. 2. During the scanning, signals are generated which are used to control the expression of the characters assigned to the individual timer marks. The location of the sign on the tape is determined with the help of its timer stamp. The timing marks are scanned by a fixed sensor, past which the individual timing marks of the circulating belt move. The impulses obtained when such a timer mark is sensed can be counted (from a start mark); the counter indicates the character that is currently in a certain printing position. However, this is only possible if you

• a) knows the arrangement of the characters on the tape (or if the electronic mapping (EBCDIC or ASCII code table of the type set) of the tape in the printer system is known) and
• b) when the counting process is started at a certain point on the tape. This point is called the start marker below.

This start marking was previously provided (in the case of the IBM 3262 printer) in the form of a missing timer mark. When the timer marks were scanned, this start mark was also recognized. The scanning pulse caused by the "start marking" could be electronically filtered out from the pulses caused by the timing marks and could thus be used for the start of the counting process for the timing marks with each tape revolution.

The type tapes of a steel tape printer are fundamentally interchangeable to use tapes with different type sets etc. and to replace old tapes with new ones.

• Nach dem Einlegen des Typenbandes in den Drucker wird ein Probeabdruck erstellt. Aufgrund dieses Probeabdruckes konnte visuell festgestellt werden, um welches Typenband es sich handelt. Daraufhin war ein entsprechender Schalter am Drucker manuell einzulegen, um die Zuordnung (Identifizierung) des Typenbandes zur Elektronik des Drucksystems vorzunehmen.

When a new type tape is inserted, however, an electronic image of this type tape must be available in the printing system for the print output to be controlled properly. If different type bands are used, different electronic images assigned to these bands must also be available accordingly. For a specific type band inserted in the printer, the electronic image assigned to it is decisive for the print output. For this reason, the printer system must be informed which tape has been used and which electronic image is to be assigned for the print output control. This type band identification was carried out as follows for the aforementioned IBM 3262 printer:

• After inserting the type tape into the printer, a test print is made. Based on this test print, it was possible to visually determine which type band it was. Then a corresponding switch on the printer had to be inserted manually in order to assign (identify) the type tape to the electronics of the printing system.

This type of type band identification is time-consuming, cumbersome and uncertain.

From the German patent application OS 25 00 263 a printer system with an automatic type band identification is known. The type band then contains a binary-coded identification mark, which is scanned. The timing marks and the synchronization or. however, the band identification information is arranged in separate tracks. This is expensive; requires an additional marking track as well as an additional sensor and amplifier.

It is therefore an object of the invention to provide a possibility for simple identification of the type carrier tape.

This object of the invention is achieved in an advantageous manner by the measures mentioned in the characterizing part of claims 1 and 3.

An advantageous development of the invention can be found in the subclaim.

An embodiment of the invention is shown in the drawings and will be described in more detail below.

• Figur 1 eine schematische ausschnittsweise Darstellung eines Typenbandes mit Zeichen, Zeitgebermarken und einer Start- und Identifizierungsmarkierung
• Figur 2 eine schematische Schnittdarstellung des Typenbandes mit einer Abtasteinrichtung für die Zeitgebermarken
• Figur 3 eine schematische Darstellung als Abwicklung der für einen Bandumlauf in Betracht zu ziehenden Zeitgebermarken sowie der Start- und Identifizierungsmarkierung
• Figur 4 ein Pulsdiagramm zur Erläuterung des Blockschaltbildes nach Fig. 5
• Figur 5 ein schematisches Blockschaltbild zum elektronischen Herausfiltern der durch die Start- und Identifizierungsmarkierung bedingten Pulse in Verbindung mit einer Zähleinrichtung für die zwischen der Start- und Identifizierungsmarkierung liegenden Zeitgebermarken als Maß für die Typenband-Identifikation.

Show it :

• Figure 1 is a schematic fragmentary representation of a type tape with characters, timer marks and a start and identification mark
• Figure 2 is a schematic sectional view of the type tape with a scanning device for the timing marks
• Figure 3 is a schematic representation of the processing of the timing marks to be considered for a tape circulation and the start and identification mark
• FIG. 4 shows a pulse diagram to explain the block diagram according to FIG. 5
• FIG. 5 shows a schematic block diagram for electronically filtering out the pulses caused by the start and identification mark in connection with a counting device for the timing marks lying between the start and identification mark as a measure of the type band identification.

In Fig. 1, the type carrier tape 1 is cut out shown wisely in supervision. The letters 1-1 to 1-7 with the associated timing marks 2-1 and 2-7 are etched out on the tape by photochemical processes; likewise the start mark 3 and the identification mark 4. The direction of movement of the belt is indicated by the arrow D.

2 shows schematically how the individual timer marks, but also the start and identification marks, are sensed. Band 1 is shown in a longitudinal section, the timing marks are marked 2-2, 2-3 and 2-4. For reasons of clarity, the associated characters are not shown in this sectional illustration. The type carrier tape runs with its timer marks past a so-called sensor. This sensor consists, for example, of a permanent magnet 7 with a soft iron tip 6 around which a coil 5 is arranged. When moving a timer mark, e.g. B. 2-2, at the tip of the sensor 4, the magnetic resistance for the magnetic flux caused by the permanent magnet 7 is reduced. (The magnetic flux runs outside the permanent magnet 7 and the soft iron tip 6 through air and the timer mark 2-2). A pulse P is induced in the coil 5 by the change in magnetic flux. When the printing tape moves past the sensor, a sequence of pulses will occur which are assigned in time to the moving timer or start or identification markings.

It has already been mentioned that a further so-called start mark 3 is arranged between two timer marks (in this example 2-1 and 2-2). This start marking is also detected by the sensor. In addition to the previously mentioned timer marks 2-1 to 2-7 and the start mark 3 is on the print tape between two other adjacent timer marks, e.g. B. 2-6 and 2-7, another mark, the so-called identification mark 4 attached. The distance between the start mark 3 and the identification mark 4 is determined by the number of timer marks between them, e.g. B. 2-2 to 2-6 defined. This number of time stamps enclosed between the markings 3 and 4 is also a measure for the identification of the printing tape. This number can be determined electronically for the circulating belt. It is also used for program-controlled addressing of a memory location in which the electronic image of this specific type band is stored. However, this provides the system with the type band information required for pressure control of the inserted type band.

In the case of other type bands with different fonts or alphabets, the identification mark 4 will be placed at a different location, so that each type band type is defined by a different distance from the start to the identification mark.

In order to avoid misunderstandings, it is expressly pointed out that the same type bands also have the same identification value.

The automatic type band identification occurs every time the printer is started. The timing mark division is identified by T in FIG. 1. The start mark 3 and the identification mark 4 are placed at a distance of T / 2 from their neighboring timing marks. After the start-up (reaching the working speed of the type band), those that go back to the start marking 3 and the identification marking 4 are filtered out from the chronological sequence of the pulses occurring at the sensor. FIG. 3 shows a processing of the timing marks to be considered for a tape circulation, as well as the start and identification marks. The number of timer marks lying between the start mark 3 and the identification mark 4 is A; the number of timing marks between the identification mark 4 and the start mark 3 is indicated by B. The number A and B is determined by two different counters. The smaller counter reading is used for tape identification (under the boundary condition that the maximum possible number of type tapes to be identified differently must not be greater than the number of timer marks on one tape half). This boundary condition is obvious if one considers that the first time a "non-timer mark" (mark 3 or 4) occurs, it cannot be stated at first whether it is the start mark or the identification mark. The start mark is recognized by the number of subsequent timer marks being less than 1/2 (A + B), where (A + B) is the total number of all the timer marks (except the start and identification marks). It follows that the total number of different bands to be identified is limited to 1/2 (A + B) - 1. In other words: in order to recognize the start marking or identification marking, A <B must be. The number A soii directly corresponds to a band identification number, which can range from 1 to 1/2 (A + B) - 1.

Various pulse time diagrams are shown in FIG. With their help, it is possible to clarify the mode of operation of the circuit shown in FIG. 6. Figure 4A shows a sequence of pulses derived from the sampled timer marks and the sampled start and identification mark.

4B shows a pulse sequence which is obtained from the pulse sequence according to FIG. 4A with the aid of a monostable multivibrator.

FIG. 4C shows a pulse sequence as it is obtained with the aid of a flip-flop FF by ANDing the pulse sequences from FIGS. 4A and 4b.

Fig. 4D shows a filtered pulse train, in which only that derived from the timing marks ten pulses appear (the pulses based on the start marking and the identification marking are missing in this representation).

Fig. 4E shows a waveform as derived from that in Fig. 4C. The rising edges of pulses 500 and 600 determine the pulse duration of pulse 700. The signal curve in diagram 4E is thus characterized by a signal missing area and a signal present area. 4E is used to control two counters. The first counter is used to detect the filtered timing mark pulses (according to FIG. 4D) during the signal-absent time in FIG. 4E (see FIG. 4F); the other counter is used to count the filtered timing mark pulses during the signal present time in FIG. 4E (see FIG. 4G).

FIG. 2 shows how the signal sequence occurring at the sensor can be generated as shown in FIG. 4A.

The signals occurring at the sensor 4 have a shape as indicated. They are amplified (8) and fed to a Schmitt trigger 9, which generates a series of rectangular pulses from them. The width of these pulses is specific to Schmitt triggers. These pulses are converted into a rectangular pulse sequence according to FIG. 4A via a monostable multivibrator 10. The pulse width of these pulses is smaller than at the Schmitt trigger output. The monostable multivibrator 10 is triggered by the start edge of the Schmitt trigger output pulses.

6 shows the block diagram of a circuit as it can be used for the automatic determination of the band identification. This circuit is supplied with the pulse train according to FIG. 4A on line 60. It contains the timer mark pulses 40 as well as the start marking pulse 50 and the identification marking pulse 60. This pulse sequence is supplied on the one hand to a retriggerable, monostable multivibrator 61 and on the other hand to a delay element 62. The monostable multivibrator 61 should have the following function:

Its output signal is set by the trailing edge of the pulses 40. A time T ₂ remains. The time T ₂ is chosen so that it is approximately plus the pulse width of the pulses 40 75% of the time T _i , which characterizes the pulse interval of the pulses 40 in Fig. 4A.

Since the start marking pulse 50 or the identification marking pulse 60 lies in the middle between two adjacent pulses 40, their falling edge causes a new start of the time condition of the output signal of the monostable multivibrator 61 for an imaginary time of T ₂ . During this time, however, a trailing edge of the pulse 40 following the pulse 50 already occurs again, as a result of which the output signal of the monostable multivibrator 61 is maintained for a further time T ₂ . Analogous to the process just described, the signal is also generated in the area of the identification marking pulse 60. The output of the monostable multivibrator 61, like the output of the delay element 62, is fed to an AND gate 63, the output of which in turn leads to a bistable multivibrator (flip-flop FFI) 65 . This circuit part is intended to perform the function of filtering out the start marking and identification marking pulses from the signal sequence according to FIG. 4A. For this purpose, the pulse train according to FIG. 4A, which is slightly delayed by the delay element 62, and the pulse train according to FIG. 4B are supplied to the AND gate 63. This AND gate 63 causes a signal at the output of the AND gate 63, which sets a flip-flop 65, to be generated for an output signal of the monostable multivibrator 61 and a rising edge of a pulse in the pulse train according to FIG. This flip-flop 65 is reset by the subsequent output signal at the AND gate 63, which is formed by a simultaneously set output signal of the monostable multivibrator and a simultaneous rising edge of a pulse in the pulse sequence according to FIG. 4A. In this way, the flip-flop (65) output signal 500 or 600 is formed, which represents the "filtered out" start marking pulse or the "filtered out identification marking pulse. The delay element 62 already mentioned has the task of slightly delaying the pulses according to FIG. 4A, so that there are clear conditions (and no peaks) when the AND element 63 is AND. For reasons of simplification, this delay function is not further considered in the pulse diagrams of FIG. 4. The output of the flip-flop FFI 65 is fed via an negation element 66 to an AND element 64, the second input of which is connected to the output of the delay element 62. This circuit part has the task of filtering out the timing mark pulses according to FIG. 4D from the pulse sequence according to FIG. 4A. This object is achieved in that the delayed Fig.4A pulse sequence is supplied to the AND gate 64, of which, however, only that part can pass through the AND gate 64 if the flip-flop signals 500 and 600 are not present.

The pulse sequence according to FIG. 4A was thus divided into two different pulse sequences, one of which (FIG. 4D) contains the timer mark pulses and the other (FIG. 4C) the flip-flop pulses 500 and 600 corresponding to the start and identification marker pulse.

With these two signal sequences FIGS. 4C and 4D, counting processes can now be controlled in a simple manner to determine the values A and B mentioned in connection with FIG. For this purpose, the output signal of the AND gate 64 becomes both an AND gate 68 and a AND gate 69 supplied. The second output of the AND gate 68 is connected via a flip-flop FFII 67 to the output of the flip-flop FFI 65, while the second output of the AND gate 69 is connected to the output of the flip-flop FFII 67 via a negation element 70. The pulse sequence according to FIG. 4C is converted into one according to FIG. 4E by the flip-flop 67. Thereafter, the flip-flop 67 provides an output signal for the time ranging from the start edge of the first flip-flop (65) output signal 500 to the start edge of the subsequent flip-flop (65) output signal 600. During this time, the filtered timer mark pulses according to FIG. 4D can pass the AND gate 68 in order to be fed to a counter CTR I 71. During the time in which the flip-flop 67 does not supply an output signal, negation (70) thereof enables the AND gate 69 to pass the timer marks ₁ > u [4e filtered according to: FIG. 4D to a counter CTR II 72 to understand. Both counters 71 and 72 are connected to a comparison circuit 73 for determining the smaller 'counter reading, the output of which on line 74 provides the smaller counter reading as a type band identification number. With the aid of this value, the associated electronic image of the type band in the memory of the printer system can be addressed under program control.

It should be pointed out at this point that the circuit described for type band identification according to FIG. 1 is only to be understood as an example. Other circuits for filtering out the start marking and identification marking pulses should be familiar to any person skilled in the art.

It should also be noted that it is also possible to derive an identification mark pulse from the lack of a timing mark. Here, the continuous sequence of the timing markings on the type tape would be interrupted at one point by a missing timer mark. Identifying such a missing timer mark as a start mark is easy to solve with conventional electronic means and is familiar to every average person skilled in the art.

The same naturally also applies to the determination of the identification marking pulse.

Claims (3)

1. Rotating exchangeable type carrier for impact printers with a track of sensable timing marks associated to the characters, and with a sensable mark M1 determining the start of control processes for character generation, and with a type carrier identification mark, characterized by the providing of a sensable mark M2 on the type carrier, the distance between mark M1 and mark M2 being electronically recordable, and serving for the automatic recognition of the type carrier.

2. Arrangement as claimed in claim 1, characterized in that marks M1 and M2 are arranged between the timing marks associated to the characters.

3. Rotating, exchangeable type carrier for impact printers with a track of sensable timing marks associated to the characters, and with a sensable mark M1 for determining the start of control processes for character production, and with a type carrier identification mark, characterized in that mark M1 and a further mark M2 are each represented by an absent timing mark, the distance between marks M1 and M2 being electronically recordable, and serving for the automatic recognition of the type carrier.

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