DE2006415A1 - Control circuit for a recording device, in particular for a printer - Google Patents

Description

OR-INa. does L.-.io μ. * i. Din — pure », on.

HÖGER - LEGAL RIGHT-GRIESSBACH - HAECKER PATENT LAWYERS IN STUTTGART

A 37 932 b

lo. February 197o

SCM Corporation
299 Park Avenue
New York, NY, USA

Control circuit for a recording device, in particular for a printer

The invention relates to a control circuit for a recording device, in particular a printer, which has a plurality of recording elements and at least as many character reproduction elements which are movable relative to the recording elements and which, when interacting, each record the corresponding character, with a first number of character register and comparator circuits for the intermediate storage of characters to be recorded as well as with one release element, in particular one electromagnet, per recording element for its actuation, the one connections of the release elements each being able to be applied to a voltage source via a switch controllable by the respective character register.

Control units for recorders and in particular

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for printers are known and are described, for example, in the Taschenbuch der Nachrichtenverarbeitung, Steinbuch von Hartwig, pp. 684-693. A character buffer for receiving the characters to be printed out in a line contains as many character cells as the printer can print characters per line. The character buffer, also referred to as a buffer memory, can be constructed from shift registers, magnetic or core memories, electromechanical circulating memories or the like. The storage of the characters to be entered in the intermediate memory and their retrieval from the intermediate memory for printing purposes can take place serially or (preferably) in parallel. A query is generally carried out in such a way that the signal of the print type ready for the printing process is compared with ceη signals of the characters temporarily stored for printing and that, if the comparison result is positive, the corresponding recording elements, for example. Electromagnets for the actuation of print hammers are activated, whereby the corresponding characters are printed out on the paper located between the type and the hammer. For the complete printing of one line may be W to repeat the process as many times just erwähten, were offered to all types of the intended character set once each for printing necessary.

The scope of such known control circuits was considerable, since the buffer had to store so many characters that should be recorded as characters per line. The object of the invention is now to devise a control circuit, in which the component cost with constant external

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Data of the recording device can be reduced.

This object is achieved for the control circuit of the type mentioned in the opening paragraph according to the present invention solved that the number of character register circles is smaller than the number of trigger elements, that also as many controllable first switches such as character register circuits are provided and each coupled to one of the character register circuits are that each of the controllable first switches with first connections of a different group of triggering elements is connected so that the latter are divided into first groups that a number of second controllable switches are provided, each of which is connected to the second terminals of a different group of release elements, so that the last are also divided into second groups, with each trigger element only one of the first and also only one of the second groups belongs, and that a switching mechanism with the second controllable switches to their successive Actuation is connected. The invention achieves the advantage that the number M of the character buffers is only a fraction of the number N of characters per line, and that is more available due to the use on the Harkt faster components nevertheless the same printing speed as can be achieved with known control circuits.

The type drum of a Troiranel printer is preferably with a large number of characters per line and corresponding print hammers and associated release coils with the inventive pen Control circuit provided. The latter has a number of cells and comparators, the number of which is less than

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is the number of hammers and trigger coils. The character cells are used to store consecutive characters, comparing the characters to be printed out and the type of printing offered by the drum before or preferably after the intermediate storage in the character cells The character cells therefore contain a character to be printed out or a corresponding expression controlling signal. Similarly, there must be a distinction between the mode of operation of those who leave the character cells or comparators Signals and the drum mechanics synchronism exist.

The electromagnets are expediently in S subgroup summarized, the second connections of the magnets each connected to a subgroup with one of S gate switches are. The control electrodes of all gate switches of a group of electromagnets are each connected to an output of one Sequence switch connected. The gate switches can be controlled rectifiers or thyristors.

In a further embodiment of the invention, the sequence switch is a cyclically working counter, the outputs of which are connected to power amplifiers.

The controllable switches expediently include time calibrators in order to set those selected by the character registers To excite electromagnets for a specific time interval.

The time interval of the time calibrator is advantageous

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shorter than the activation time of a switch position of the Pole switch, in which latter the gate switches are open.

Further details and features of the invention can be found in the appended claims and / or the following description which serves to explain an exemplary embodiment of the invention shown in the drawing. Show it:

1 shows a partially schematic block diagram of an exemplary embodiment of the invention, which is a control circuit for a recording apparatus in the form of a drum printer;

FIG. 2 shows a schematic view of the essential part of the drum printer, for the control of which the in FIG. 1 control circuit according to the invention shown is particularly suitable.

The reference symbol Io in FIG. 1 shows an exemplary embodiment for a control circuit according to the invention, which is suitable for controlling display devices, recording devices and, in particular, printers. The control circuit Io, which can be used per se for different types of recording devices, is explained for better illustration in such a way that it is used to control a drum printer shown in FIG. 2 with 80 characters per line. A rotating drum 12 has 80 character columns on its circumference, each line of which has 80 characters of the same printing type. Each drum gap is a print hammer lh and one designed as an electromagnet

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Trip coil 16 assigned. The latter is used to control or actuate the hammer I ¹ J. The total of 80 tripping coils 16 are controlled individually and independently of one another in the control circuit Io. An index wheel 17 rigidly coupled to the drum 12 emits line signals via a line pick-up 18a which indicate the type of characters provided on the drum. A basic position sensor 18b can be used to more easily determine the basic position of the drum 12. The pickups 18a, 18b can also be organized and used in other ways.

In general, the control circuit Io is used for modulation such recording devices are used in which a control is advisable that operates in such a way that an or several characters to be recorded are stored and after a comparison with the line signal to excite the corresponding Trigger coils 16 are used in the event of a coincidence between the line signal and the one for recording

| designated cached characters was detected. In this way, that character is recorded that corresponds to a positive target / actual comparison between the the line signal representing characters ready on the drum and the buffered signal intended for recording Sign corresponds. In more detail, the control circuit Io includes one consisting of 16 character cells 21-27 Buffer 2o. The latter can be part of a total character memory that is also used in a different way, whereby the Reference numerals 21-27 only 16 active lines from this

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total Speieher not shown; the characters in memory 2o intended for printing can have been loaded serially or in parallel; In a preferred embodiment, an at least quasi-parallel invitation of 16 characters is provided during a ring counter time of a ring counter 40, ie during a counting interval. It is a particular feature of the invention, like that the number of characters of the memory cells 2o is smaller than the total number of trigger coils 16; In the embodiment of FIG. 1 there are 16 character cells opposite a total of 8o trigger coils. In the drawing of the figure, only seven of the 16 character cells are shown in total. Depending on the desired printing speed or on the basis of other factors, the number of character cells in the memory 20 varies within certain limits; however, this number is always less than the number of trigger coils or the corresponding print hammers or recording elements, ie the number of characters per line.

According to the invention, the output signals from a \

positive comparison of the line signal with the characters stored in the 16 character cells of the application of such trigger coils 16, which were selected by the ring counter ¹ Io during a counting interval. The ring counter ¹ Jo successively and respectively connects one of five groups, the first group of which is identified by the reference numeral 3o, the second group by the reference numeral 36 and the fifth group by the reference numeral 38.

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A positive output signal from the ring counter <Ίο, for example, on a line Hl four gate circuits

31 - 3 ¹ * opened via a Darlington driver 5o. As a result, the sixteen trip coils 16 of the first group 3o shown at the top in FIG. 1 are selected. The gate switches 31-3Ί can, for example, be thyristors or controlled rectifiers.

In Fig. 1, the right connection is the top four trip coils 16 connected to the anode of the gate switch 31, the cathode of which leads to a negative voltage and the Gate connection is connected to the output of the Darlington driver 5o. The gate switches are in the same way

32 - 3Ί of the first group switched; their gate connections are also connected to the output of the Darlington driver 5o. The right connections of the uppermost 16 tripping coils 16 could also be led to a different number of gate switches or to just a single gate switch, the control connection of which is connected to the ring counter ^ o via the line kl. This is purely a question of the current-frequency characteristics of the gate circuit.

A second output line k2 from the ring counter Ίο forms the control line for the gate switch or gate switches of the second group, which can be switched in the same way as those of the first group, with the interposition of a driver 51. Finally, a fifth output line ^ 5 leads from the ring counter ko via a driver 52 to the control inputs

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the gate switch of the fifth group, which selects the sixteen trigger coils 16 drawn at the bottom in FIG. 1 of the total of 80 trigger coils. If, for example, only Io character cells were provided per buffer memory 2o in the case of a drum with 8o characters per line, the release coils 16 would be divided into groups of ten, so that instead of the five groups 3o, 36, 38, eight groups are now provided, which are now followed by one that counts up to eight Ring counter would be switched on individually and successively. G

Isolating diodes 16a in series with each of the total of 80 trip coils 16 prevent reverse currents from one to another Group, whereby a selection of coils outside the group selected by the ring counter 4o is excluded.

The ring counter 4o can, for example, during the duration of a single line signal from the line pick-up 18a successively select the five groups in five equal counting intervals by sending a first counting interval signal to the line 41, then a second counting interval signal to the line 42, etc. and finally a fifth counting interval signal to the Line 45 is sent. Preferably f beginning of each counting interval into the buffer memory 16 characters are invited, the contents of the line signal preferably immediately coincidence tested is _a which a corresponding pressure signal is generated to act upon one of the sixteen trigger coil 16 with positive verlaufendem comparison that the a group by Ring counter 4o are selected. Between the loading of the character cells 21-27 of the intermediate memory 2o, the corresponding creation of pressure signals based on the coincidence found and the advancement of the

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Ring counter 4o therefore has a time allocation and synchronization.

A positive control signal on the output line 4l des Ring counter 4o during the first counting interval acts on a first in the Darlington driver 5o via a diode 55 npn transistor 53 and via this a further npn transistor fc 54. The transistors 53 and 54, which become conductive as a result, lead a trigger current to the gate inputs of gate switches 31 - 34, whereby their anode-cathode path becomes low-resistance. The gate switch can be blocked at the end of the counting interval a cessation of the trigger current can be effected via the Darlington driver 5o or if this was used for pure ignition and for a shorter time than the counting interval lasted - by stopping the corresponding pressure signals. In the same way the other four groups 36, 38 are selected.

The outputs of each of the 16 character cells 21-27 of the buffer store 2o each lead to coincidence elements k 21a-27a, the other inputs of which receive the line signal can. Each character cell is preferably followed by a coincidence element, which in turn controls a monovibrator, in the case of coincidence, the desired pressure signal is sent to a trigger coil 16 of each group via the respective of the Coil upstream isolating diode 16a supplies. In Fig. 1, the monovibrators 6o are time calibrators 6l-67 realized, which each have an RC input and a Darlington driver output. The RC input of the Time calibrator 6l represents the coincidence element 21a, whose

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Line signal input is symbolized by the input provided with the resistor R and its character input by the capacitive input 73 »74. Of course, AND switches or other devices can be used for the coincidence elements. The particular advantage of the RC input of the time calibrator lies in the fact that a special clock signal is saved when performing the coincidence comparison. The character cell 21 leads λ to the coincidence element 21a, the further input of which is connected to the line pickup 18a. The element 21a already forms the input of the time calibrator 61, which is triggered in the event of a coincidence and sends a time-calibrated pressure signal to the trigger coil 16 of each of the five groups shown at the top in FIG. 1 via a Darlington driver output. Because of the isolating diodes 16a connected upstream of the coils 16 and the selection of only one group of the total of five groups by the ring counter ko , only that trigger coil 16 whose gate switch is open is thereby excited. The duration of a pressure signal will expediently be at most equal to the duration of a counting interval, so the pressure signal should generally be no later than after switching over the (

Ring counter 4o to be extinguished on a next group.

The design of the monovibrators 6o is explained using the example of the time calibrator 6l in FIG. 1, which is shown in detail. A line 73 leads from the output of the character cell 21 of the character buffer / 'u 2o via a capacitor 7 ¹ J, which represents the C element of the RC input of the time calibrator 6l, to a connection point which is connected to the R element,

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whose second input can be fed by the line signal. The connection point is via a diode 75 in the conduction direction coupled to the base of a pnp transistor; the transistor 7o has a positive voltage on the emitter side, on the collector side via a working resistor to a negative voltage. The base of transistor 7o is via another resistor R., to the negative voltage source connected, the latter is designed so that the base of the transistor 7o in the normal state, i.e. in the non-triggered State, negative voltage leads, whereby the transistor 7o directs. A positive voltage surge across the capacitor 7 ^ can only occur through a positive preselection of seldom the R element Trigger transistor 7o, i.e. make it non-conductive.

The collector of the transistor 7o is connected to the base of a further pnp transistor 71; its emitter is provided with positive voltage via two series-connected base-emitter paths of transistors 76, 77 linked in a Darlington circuit; the collector of transistor 71 is linked to negative voltage via a load resistor and, on the other hand, via a _{capacitor 72 acting as a time-determining element C v} via a first diode. Base of transistor 7o and connected to positive voltage via a second diode. The common connection point between the first and second diode and the capacitor 72 is at the anode of the first and the cathode of the second diode. The transistor 71, which is connected in opposition to the transistor 7o and is capacitively cross-coupled to it on one side, blocks in the normal state as a result of the positive potential contained by the collector of the transistor 7o. Diodes 76a, 77a in the conduction direction from the base to. Emitter of transistor 71 and 76 prevent an increase

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the blocking potential at the base and thus enable a quick connection in the event of triggering.

As already mentioned, the transistor blocks when it is triggered 7o, whereby the transistor 71 receives a negative base voltage and begins to conduct by drawing current through the base links of the Darlington driver 76,77. The latter are thus

low resistance in their emitter collector line, whereby the d

Collectors of the Darlington driver output the positive pressure signal. A positive voltage surge across the capacitor 72 as a result of the connection of the transistor 71 acts on the base of the transistor 7o in the sense of positive feedback; the duration of the pressure signal and thus the time calibration of the blocking potential at the base of the transistor 7o, which is lengthened by the positive feedback, corresponds essentially to the time constant R _M. C ".

The RC input circuit of the time calibrator 61 can also be designed so that the resistance input is constantly connected to positive voltage, the capacitive input via ,

However, the capacitor 7 ¹ I and the line 73 only transmits a positive voltage surge if a coincidence between the character in the cell 21 and the Zeil-snsignal has been established. Furthermore, the cell 21 (and correspondingly the other cells 22-27) can represent a pure single-bit memory which is only loaded in the event of coincidence.

The second diode located at the common connection point of the two diodes with the capacitor 72, the anode of which is connected to positive voltage, delivers after the shutdown door ?; ^: "s"

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calibrator 61 a positive, sufficient amount of charge the plate of the capacitor 72 connected to the common node, whereby the time calibrator 6l as well as Generally, all group 6o monovibrators have short recovery times. The trailing edge of the pressure signal is also by a connection of the collector line of the leading to negative voltage via a diode and a resistor Darlington driver cut so that after switching the ring counter ^ o to the next group no disturbance whatsoever of the further process is to be expected. In addition, the anode of the selected gate switch is switched on at the end of the counting interval stronger negative potential, so that the gate switch is safely extinguished even if the ignition current is just in progress.

Regarding the mode of operation of the circuit, let us assume that the drum provided with 80 characters per line is continuously driven, whereby line signals are continuously picked up by the index wheel 17 and applied to the Koinaiden members in a regular cycle. The ring counter Ίο open the gate switch 31-3 ** in a first counting interval by means of a positive signal on the line kl. As a result, the first group is selected, ie the top 16 trigger coils 16 can be energized in the first counting interval that is now running. The 16 character cells 21-27 of the character buffer memory 2o are loaded with characters to be printed out; If a coincidence is established between the line signal and the bit configuration of one or more of the characters to be printed out, a print signal results from these coincidence elements

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via the corresponding monovibrators 6o. It is the case assumed that the character of the character cell 21 is equal to the character signal and thus there is a coincidence, whereby the time calibrator 61 is triggered. That the Darlington driver output of the time calibrator 6l leaving pressure signal could excite a total of five trigger coils 16, if their right connection directly to minus voltage would be.

As a result of the selection of the first group 3o by the ring counter I ¹ Io, however, the pressure signal is only able to excite the trigger coil 16 shown at the top in the drawing in FIG. 1 by drawing the current through it and the gate switch 31 to minus voltage. The pressure signal generally ends at the end of the counting interval. The release coil 16 excites the corresponding print hammer 14 to strike the drum 12, whereby the corresponding character in the corresponding column is printed out on the paper located between the print hammer Ik and drum 12. For the next counting interval, the following second group is selected; it is possible that the drum still sends the same line signal via the index wheel 17 and the line pick-up 18a, which, for example, lasts A until the end of the fifth counting interval after the fifth group has been selected. However, it is also possible for a next or another line signal to be present during the second counting interval, which indicates that the drum 12 is running at relatively high speed. During the second counting interval and during the further counting intervals, the same sequence takes place as was described above for the first counting interval. It is also possible to use the memory cells 21-27

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to be loaded successively or at least to be read out successively and checked for coincidence, the successive and serial The coincidence check is synchronized with the line signal clock have to be. In principle, line signals, print signals and counting intervals should run synchronously with one another, with however, the frequency relationships between the print signal, line signal and counting interval can be freely selected. The loading of the Character cells and / or their query can therefore take place in parallel or in series. The number of character cells per buffer 2o can be anything, but generally does not exceed half the number of characters to be printed per Row. The number of groups to be switched on cyclically by the ring counter increases as the number of character cells increases sinks. As in the embodiment of FIG. 1, the number of character cells is one fifth of the number of characters there are five groups per line.

Changes are therefore within the scope of the concept of the invention from the embodiment shown in terms of the number of groups and character cells, as well as in terms of Signal frequencies of the print and line signals as well as the counting intervals are possible. Although the embodiment shown is a control circuit for an electromechanical Printer concerned, the inventive idea can also apply to control circuits for other recording devices and Display devices are applied.

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Claims (10)

Claims 1. Control circuit for a recording device, in particular a printer, which has a plurality of recording elements and has at least as many character reproduction elements movable relative to the recording elements, which each record the corresponding character I when interacting, with a first number of character register and comparator circuits for the temporary storage of characters to be recorded and each with a trigger element, in particular one electromagnet per recording element to actuate it, one of which is connections the triggering elements can each be applied to a voltage source via a switch controllable by the respective character register, characterized in that the number of character register circles (21-27) is smaller than the number of triggering elements (16) that, furthermore, just as many controllable first switches (74, 61-67) such as Character register circles provided and each with a j of the character register circuits are coupled, that each of the controllable first switches is connected to first connections of a different group of tripping elements, the latter are divided into first groups, that a number of second controllable switches (3o and 5o, 36 and 51 etc.) are provided is, each of which is connected to the second terminals of a different group of triggering elements, so that the latter are also divided into second groups, each triggering element belonging to only one of the first and also only one of the second groups, and that a switching mechanism with the second controllable switches to their successive Actuation is connected. 009836/1895 - Io - A 37 932 b b - 93 Io. February 197o 2. Control circuit for a recording device, in particular according to claim 1, preferably.a printer which has N recording elements and at least as many character reproduction elements (hammers) which are movable relative to the recording elements and which, when interacting, each record the corresponding character, with a plurality of character registers (21-27 ) for the intermediate storage of characters to be recorded and each with a trigger element, in particular an electromagnet (16) per recording element for its actuation, wherein the one connections of the trigger elements can each be applied to a voltage source via a switch controllable by the respective character register, characterized in that the trigger elements (16 ) are combined in groups of H elements each, that furthermore only M character registers (21-27) and M controllable switches (7 ^, 61-67) are provided, which are connected to corresponding triggering elements of the different groups are, and that a switching mechanism ( ¹ Jo, 5o, 31-3 ¹ O is provided for the second connections of the release elements in order to excite the latter in groups. 3. Circuit according to claim 2, characterized in that the electromagnets are combined in S subgroups, the second connections of the magnets in each subgroup being connected to one of S gate switches (31-3 ¹ O). 4. A circuit according to claim 3, characterized in that the control electrodes of all gate switches are each connected to a group of electromagnets to one output of a ^{sequence switch (1} Jo, 5o - 52). 009836/1895 - 19 - A 37 932 b lo. February 197o 5. A circuit according to claim 4, characterized in that the The next switch is a cyclical counter (4o). 6. A circuit according to claim 5 »characterized in that the outputs of the counter power amplifier (5o - 52) are downstream. 7. Circuit according to one or more of the preceding claims, characterized in that, in a known manner, the controllable switches comprise time calibrators (61-67) in order to f to excite the electromagnet selected by the character registers for a specific time interval. 8. Circuit according to one or more of the preceding
Claims 3 to 7, characterized in that the
Gate switch controlled rectifiers or thyristors
(31 - 3 ¹ ») are. 9. Circuit according to one of several of claims 3 to 8, characterized in that the product of the number W of electromagnets per subgroup and the number S is equal to N. is. 10. Circuit according to one or more of claims 7 to 9 »characterized in that the time interval of the time calibrator is shorter than the activation time of the 7..I ge switch . 009836/1896 Blank page