DE3414355A1 - Method for controlling the print hammers of line printers and a circuit arrangement for carrying out the method - Google Patents

Abstract

The invention relates to a method for controlling the print hammers of line printers and a circuit arrangement for carrying out the method. In accordance with the method, the control of the print hammers is ensured with consideration of the requirements regarding flight time for a duration longer than the adjustment of the character carrier in two successive character layers, two comparison subcycles being triggered in each character layer; during the first subcycle, in addition to the result of the comparison the hammer register has also input into it its own, preceding state by means of a logic OR connection and the control of the hammer takes place at the end of the first subcycle in accordance with the instantaneous state of the hammer register. In the second comparison subcycles, the cells of the hammer register are cleared, in which subcycles the control of the hammer must be switched off. The circuit arrangement suitable for carrying out the method contains, in addition to the hammer register (1), a memory register (2) with the same number of cells as that of the hammer register (1), and this memory register (2) is connected to the hammer register (1). The latter is realised with a shift register between whose series output and series input a feedback loop is formed via a logic circuit. <IMAGE>

Description

34H355

VIDEOTON Elektronikai Vällalt, Szekesfehervär / UMGARN

METHOD OF CONTROLLING THE PRESSURE HAMMER OF LINE PRINTERS AND CIRCUIT ARRANGEMENT FOR IMPLEMENTATION

OF THE PROCEDURE

The invention relates to a method for controlling the printing hammers of line printers and a circuit arrangement to carry out the procedure.

VIDEOTON ELECTRONIKAI VALLALJYT _; Sept. 18, 1984

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Several methods are known for controlling the printing hammer of line printers. In the developed high-speed line printers, the printing hammer has a longer flight time than the time required to move two consecutive characters on the character carrier into the printing position. Accordingly, the already started hammer should be used for. can be controlled with drive current for a longer period than the cycle duration of the character belonging to the given character.
An obvious solution to the problem is to equip the independent circuit for controlling each pressure hammer with a timing circuit, for example a monostable multivibrator, which maintains the drive current for the required duration when the hammer is started. A line printer with, for example, 136 character positions requires 136 monostable multivibrators of high accuracy, which results in considerable additional costs. At the same time it should be possible to regulate the time setting of the individual time circles so that the time control can be equated precisely with the flight time of the print hammer. Independent time circles can only be set individually, which can only be done very laboriously and with great care.

The hammer drive group, for example, is based on this principle the line printer type 2310, 2410, 2240 and 2470 from the American company Dataproducts and type PF71 from Honeywell company.

Even without independent time circles, the hammer can can be controlled. For example, the line printers type 2230 and 2260 from Dataproducts have two independent Hammer registers used, their output signals through 136 multiplexers system 2/1 for the hammer drive groups be summarized. However, because of the large number of multiplexers, this solution is to be regarded as costly. The aim of the invention was to develop a method and a circuit arrangement for control the print hammer of line printers that allow for every hammer without independent circuits

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To ensure control current for the required duration and the simultaneous adjustability of all control times.

The object is achieved by a method according to which the character information of the line to be printed in the individual character layers of the character carrier is compared with the character determined by the given position, the result of the comparison is stored in a hammer register and the printing hammer assigned to the cells determined by the match are started, in the sense of the invention in each character position of the character carrier two comparison sub-cycles are carried out, in the first comparison sub-cycle in the hammer register at the same time for entry with the result of the comparison in a logical OR context, the own, immediately preceding position is introduced, and the print hammers be controlled according to the state of the hammer register at the end of the first comparison sub-cycles, so that? in second comparison sub-cycles after the control, those cells of the hammer register are cleared for which the control of the print hammer is to be set.

In order to ensure the adjustability of the termination time of the control, in one embodiment of the method, the hammers in the period between the completion of the second comparison sub-cycle and the first comparison sub-cycle of the following cycle according to the current state of the hammer register driven again.

In an advantageous embodiment, the character carrier cycles 1 and 2 corresponding duration, in the second comparison sub-cycle again that corresponding to the current position of the character carrier Comparison carried out.

To implement the method according to the invention, a circuit arrangement is also provided that has a Hammer register with cells in a number equal to that of Characters in a line, as well as hammer drive circuits and print hammer connected to its outputs

with the outputs of the individual cells of the Hammer register via a storage register with the same number of cells with the hammer control circuits in Are connected and the serial input of the hammer register via a logic circuit to your own Serial input, the read input of the memory register to an overwriting clock input, the overwriting clock at twice the rate than the character clock rate of the character carrier is connected.

It is also advantageous if the logic circuit has an AND gate, one of the inputs being connected to the series output of the hammer register, the other input with a gate input, furthermore an OR gate, one of which the inputs with the output of the comparator delivering the result of the comparisons, the other input with the output of the AND gate and the output is connected to the serial input of the hammer register, having.

The task set is with the invention Arrangement only with a small amount of circuitry quite resolved.

The solution according to the invention is further illustrated with the aid of a few examples with reference to the accompanying drawing explained in detail. The drawing shows: FIG. 1: Simplified block diagram of a possible

Embodiment of the invention Circuit arrangement.

The printer can print η pieces of characters in each line, and accordingly there are η pieces of hammers before. The individual lines are printed in steps corresponding to the number k of possible characters, in accordance with how the individual characters of the character carrier are brought into print position.

If a given character of the character carrier is brought into print position, the data content of the line to be printed is compared with the given character for each character position, and if this comparison outputs the result "yes", one of the comparison

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outputs the logic level ^H l ", and if" no ", the logic level" 0 ".

Let the number η be 136 and the number of characters 64. As is known, the comparisons very quickly with regard to the individual character positions carried out successively so that between two character positions accompanied by the character offset signals are, the comparison of all positions is ended, and at the output of the comparator there are 136 logical Signals in close succession.

In Fig. 1, the hammer register 1 is implemented with a shift register with η cells, the series input of which is connected to the comparator output B via an OR gate. The series output of hammer register 1 is connected to the second input of the OR gate via an AND gate. The switching on and off of the resulting feedback can be controlled with logic levels given at gate input C. The shift input of the hammer register is connected to the shift control terminal D, which is controlled in a synchronized manner for the comparison of the individual character positions.

The outputs of individual cells of the hammer register 1 are connected to parallel read-in inputs of individual cells of the memory register 2 in connection. The read input of memory register 2 is connected to the write clock input A, which controls the actual printing. The overwriting clock has a rate twice that of that character clocks accompanying the character layers.

The outputs of individual cells of the memory register are via the η piece hammer drive amplifier 3 with the individual hammers 4 connected.

The circuit shown in Fig. 1 operates with reference to an embodiment of the method according to the invention as follows.

It is assumed that the time required to control the individual hammer 4 is greater but at most is twice as large as that for moving two consecutive characters of the character carrier into the

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Time required to cover the effort of the to keep 4 independent time circuits to be assigned to individual hammers for the corresponding time control low, the hammer control is to be ensured by the pressure control for the corresponding duration.

It is assumed by way of example that the character carrier is in the position corresponding to the printing of the character G. is offset, and the character G must be printed in character position 15,

According to the invention, two comparison cycles are carried out in each character position of the character carrier. In the first comparison cycle, gate input C receives control 1 and the hammer register's feedback loop 1 is closed. After the comparison and offset cycle, which is made up of a total of 136 steps, in the individual cells the logical sum of the result of the comparison with regard to the corresponding character position and the value stored in the same cell of the hammer register 1 thanks to the feedback.

In the present example, cell 15 was empty and the logical value 1 was the result of the comparison with respect to the character G is entered in cell 15 of the hammer register 1 in this comparison sub-cycle. Subsequent to the executed first comparison sub-cycle, the content is activated by activating the rewrite clock input A rewritten from hammer register 1 to storage register 2. At the moment of transcription, the one at the exit of the cell leaves 15, the level "1" appearing on the hammer 4 corresponding to the character 15, and it becomes continuous drive for it ensured.

After the rewrite cycle has elapsed, the second comparison sub-cycle is still in the same position of the character carrier immediately started, with ^ the gate entrance C receives a prevention so that the feedback turns off. At the end of the comparison sub-cycle, levels only become "1" Received in cells of the hammer register 1, where character G must be printed in the appropriate place.

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y 3 A14 3 5 5

Accordingly, the logic level "1" remains in cell 15 obtain.

Subsequent to the second comparison sub-cycle, still in the cycle of the character G, the rewrite clock input is activated A controlled a second time. As a result, the content of cell 15 is not used in the present example influenced, and the control of the hammer 15 continues.

In the printing cycle of the next character H, all of this is repeated in a similar manner. In the first comparison sub-cycle, when the feedback loop is closed, its previous value "1 ^M " is entered in cell 15, although obviously only an "O" can result from the comparison with regard to the character H. In position 15, the hammer control is accordingly through the first rewrite cycle of the character H is not changed, and the hammer 15 already receives its drive current in the second character position. During the second comparison sub-cycle provided for the character H, however, only the result "O" of the for the Character H is written into cell 15, so that at the time of the second rewrite cycle, input 15 of memory register 2 will have the value "O." The drive current of hammer 15 is interrupted and character G is printed.

In the course of the individual character layers, the comparison sub-cycles require a relatively small amount of time on. Therefore, the first rewrite cycle occurs relatively quickly in the present time span.

The second rewrite cycle can occur in the period between the end of the second comparison sub-cycle and the first comparison sub-cycle of the following character take place at any moment. The phase position of the second rewrite cycle can be adjusted, whereby it is determined how long the print hammer 4 over the duration of a complete character position

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can be controlled within the second.

The solution described can be used with success if the duration of the hammer control in the duration of the Character positions 1 and 2 fall. Often longer drive times could also be required. According to the invention the second comparison sub-cycle should be provided for the determination of the hammers to be adjusted.

Let it now be assumed that the control of the hammer by the character G must be ensured for the duration between the character positions 2 and 3.

During the individual character cycles, the first comparison sub-cycle is still to be carried out with the feedback loop closed, and the comparison is carried out with respect to the current print character. In the position of the character carrier corresponding to the character G, the logic level "1" is therefore in cell 15 entered, and the hammer 15 receives its drive current at the first rewrite cycle. Different from the previous one Case only the second comparison sub-cycle is established. Now the hammers need to be turned off, the two of them Characters were left on earlier, i.e. when the character E was printed. In the second comparison sub-cycle, the comparison with the data content regarding the character E / which is obviously available / made, in any case, a so-called negative comparison takes place, since the functions of the comparison output B and of gate input C can be swapped with regard to the previous example: The comparison output B receives the control logic "0", while the comparator connects to gate input C with inverted output. In this way, in the positions corresponding to the character E, the logic level in hammer register 1 does not become "1" but "O" is recorded.

In this example, the receives at position 15 at Character G, hammer left on during the two comparison sub-cycles of character position H following character position G iamerfort its drive, as the one in position 15 as a result

Feedback inscribed "1" through the during

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of the second comparison sub-cycle for the character F does not affect the negative comparison will. In the second comparison sub-cycle, the character position I following character position H is indicated the negative comparison to the two characters earlier G, where in cell 15 of the Memory register 2 the value "O" ■ entered and at second rewriting cycle of the drive current of the hammer 15 is set.

The purpose of the second comparison sub-cycle was also in the first example to determine the one to be switched off Hammers, but it also becomes a simple solution with the double comparison with the same sign achieved without, however, having to make a negative comparison with respect to an earlier character.

It is also easy to see that the hammer control is longer than three times the character position as well can be resolved if the negative comparison is made for the characters several steps earlier will.

The solution according to the invention enables the hammer control to be ensured for the required duration with simple circuits without the need for otherwise necessary time circuits for the individual character positions.

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Claims (5)

34U355 VIDEOTON Elektronikai Vällalat, Szekesfehervär / HUNGARY PROCEDURE FOR CONTROLLING THE PRESSURE HAMMER OF LINE PRINTERS AND CIRCUIT ARRANGEMENT FOR IMPLEMENTATION OF THE PROCEDURE Patent claims: ( 1.1 Method for controlling the print hammer of line printers, whereby the character information of the line to be printed in the individual character layers of the character carrier is compared with the character determined by the given position, the result of the comparison is stored in a hammer register and the one determined by the match Pressure hammer assigned to cells are left on, characterized in that two comparison sub-cycles are carried out in each character position of the character carrier in the first comparison sub-cycle in the hammer register at the same time as the entry with the result of the comparison in a logical OR connection is its own, immediately preceding one Position is introduced, and the print hammer at the end of the first comparison sub-cycles the state of the hammer register are controlled accordingly, so that in the second comparison sub-cycles after the control, those cells of the hammer register can be deleted, for which the control of the print hammer is to be set. 2. The method according to claim 1, characterized in that the hammers in the period between the completion of the second comparison sub-cycle and the first comparison sub-cycle of the following cycle according to the current state of the hammer register can be controlled again. 3. The method according to claim 1, characterized in that, depending on the hammer control requirement, the character carrier cycles 1 and 2 correspond accordingly _ ₂ _ 34U355 Duration in the second comparison sub-cycle, the comparison corresponding to the current position of the character carrier is carried out again will. 4. Circuit arrangement for carrying out the method according to one of claims 1 to 3, comprising a hammer register (1) with cells in a number equal to that of the characters in a Row as well as hammer drive circuits (3) and print hammer (4) connected to its outputs, characterized in that the outputs of the individual cells of the hammer register (1) via a storage register (2) with the same number of cells connected to the hammer drive circuits (3) and the series input the hammer register via a logic circuit to its own serial input, the read-in input of the memory register (2) to an overwrite clock input (A), the overwrite clock generated at twice the rate of the character clock rate of the character carrier, is connected. 5. Circuit arrangement according to claim 4, characterized in that the logic circuit has an AND gate, one input with the serial output of the hammer register (1) and the other input with a gate input (C) is connected, and furthermore has an OR gate, one input of which is connected to the output (B) of the result the comparator providing the comparison and its others The input is connected to the output of the ÜND gate and the output is connected to the serial input of the hammer register (1).