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Publication numberUS3846801 A
Publication typeGrant
Publication dateNov 5, 1974
Filing dateMar 21, 1973
Priority dateMar 30, 1972
Also published asDE2215519A1
Publication numberUS 3846801 A, US 3846801A, US-A-3846801, US3846801 A, US3846801A
InventorsDumont H, Reum H, Strohwald R
Original AssigneeBosch Gmbh Robert
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Method and apparatus for electrographic drawing
US 3846801 A
Abstract
Electrographic drawings and facsimiles are made by applying signals sequentially to a multiplicity of writing electrodes in an array in contact with an electrosensitive paper medium. The signals are distributed to the respective electrodes by time-division demultiplexers, and the pulse length of the pulses applied to the electrodes is adjustable to a value less than the burnout time by adjusting the duration of the pulse provided by a monostable flipflop inserted in the signal chain ahead of the demultiplexer input.
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United States Patent 1191 DuMont et a1.

METHOD AND APPARATUS FOR ELECTROGRAPHIC DRAWING Inventors: Hans-Christoph DuMont,

Malmsheim; Rainer Strohwald; Helmut Reilm, both of Stuttgart, all of Germany Robert Bosch GmbH, Stuttgart, Germany Filed: Mar. 21, 1973 I Appl. No.1 343,397

Assignee:

Foreign Application Priority Data Mar. 30, 1972 Germany 2215519 US. Cl 346/74 E, 178/66 R Int. Cl. 601d 15/06 Field of Search 346/74 ES, 74 E, 74 SB,

346/74 SC; 178/66 R, 6.6 A

References Cited UNITED STATES PATENTS 4/1969 Rudy 346/74 E vIDEO 1 1 Nov. 5, 1974 3,553,718 1/1971 Schierhorst et a1. 346/74 E 3,611,411 10/1971 Mashier et a1. 346/74 E 3,613,103 10/1971 Harris 178/66 R 3,644,931 2/1972 Stringer et al 1. 346/74 E Primary Examiner-Vincent P. Canney Attorney, Agent, or FirmFlynn & Frishauf Electrographic drawings and facsimiles are made by applying signals sequentially to a multiplicity of writing electrodes in an array in contact with an electrosensitive paper medium. The signals are distributed to the respective electrodes by time-division demultiplexers, and the pulse length of the pulses applied to the electrodes is adjustable to a value less than the burnout time by adjusting the duration of the pulse provided by a monostable flipflop inserted in the signal chain ahead of the demultiplexer input.

ABSTRACT 11 Claims, 3 Drawing Figures RESET CONTROL METHOD AND APPARATUS FOR ELECTROGRAPHIC DRAWING The invention relates to a method and apparatus for recording or reproducing visual information on electrosensitive sheet material, particularly on metallized paper. In particular, the invention concerns the use of writing electrodes arranged next to each other in an array in which each of the electrodes is insulated from the other and is controlled by an individual controllable semiconductor device.

Methods and apparatus of this type are known in which one or more groups of writing electrodes are constructed in the form of a so called electrode comb. In these arrangements, a separate signal source is used for each writing electrode and all of the signal sources simultaneously control the individual writing electrodes. The simultaneous activation of the writing electrodes gives rise to the disadvantage of circuit bridging between electrodes.

It is an object of this invention to provide a method and apparatus for activating a multiplicity of juxtaposed writing electrodes to produce or reproduce graphic material, which avoids the disadvantage of bridging between electrodes.

SUBJECT MATTER OF THE PRESENT INVENTION Briefly, the electrodes are activated and controlled sequentially and the individual periods for which a single electrode is in circuit is kept shorter than the time in which a limiting effect in the writing is reached as the result of local burnout. Electrographic writing on metallized sheet material produces a small are that causes metal particles to coalesce. By thus destroying the con tinuity of the metal film locally, the maximum electrographic effect is reached when the arc burns out. It is desirable to conduct the operation without any of the electrodes being activated long enough to reach burnout, even on a maximum signal. The electrodes are preferably arranged in a line which sweeps across the paper and they are preferably energized in a progressive sequence in with each is connected for energization after the preceding one in line. Any arbitrary sequence can be used, however, especially for encoded transmission cases. The electrodes may, if desired, be arranged for closer packing in a staggered array, for instance, rather than all in one line.

To produce the sequential operation of the writing electrodes, a time-division demultiplexer is used to distribute time subdivisions of the signal to the respective electrodes. The number of outputs of the demultiplexer must then be equal to the number of writing electrodes of the electrode group.

The invention is particularly useful for reproduction of line drawings and incidental lettering and printing, and other two-valued (black and white, for example) graphic information. The information to be displayed on the electrosensitive sheet material is first supplied to one input of a two input NAND gate, the other input of which is constituted by the clock pulses supplied by a timing circuit. The result is a series of pulses of length determined by the clock pulses (i.e., by their period, duty cycle and polarity) and their presence or absence in any clock pulse period is dependent on the state of the input information in that period. The demultiplexer is advanced by means of a binary counter which operates in response to the same clock pulses that are applied to the aforesaid NAND gate. The input to the demultiplexer is thus switched in turn to each of the outputs. Successive signal pulses proceed from each of these outputs in turn to the respective control electrodes of semiconductor devices each of which electrically drives one of the writing electrodes. The maximum pulse length is less than the clock pulse period, so that each electrode is activated for just one pulse and one signal pulse reaches only a single electrode.

In a further developed form of the invention, it is found desirable to provide a monostable flip-flop (monoflop) circuit having a manually adjustable period to determine the pulse length and to interpose this circuit between the output of the NAND gate and the signal input of the demultiplexer. ln this case, the pulses furnished by the NAND gate to the monostable flip-flop may be either short or long, however the clock pulse gating may produce them, since the monoflop can operate either as a pulse stretcher or a pulse shortener. The modification of the writing time made possible by the adjustment of the period of the monoflop circuit provides control over the point size and hence the degree of blackness of the graphic display, so that writing at various values of gray is possible.

In another illustrative embodiment of the invention the writing electrodes are grouped in a plurality of adjacent groups or sub-arrays, each of which comprises the same number of writing electrodes. Such an apparatus is also drven so that all of the writing electrodes are driven in sequence and that the period for which a single electrode is activated each time is less than the period in which the writing process would come to an end by burnout. In this embodiment of the invention, each sub array of electrodes and their respective driving semiconductors is provided with one of a number of identical demultiplexers, all of which are advanced by a common binary counter. A number of additional flipflops form a 3 bit binary counter provided for enabling each of the demultiplexers in turn for a complete demultiplexing cycle, so that the signal inputs of all the demultiplexers may be continuously fed in parallel with the same input signal. An extra set of NAND, is interposed between the pulse length determining (monoflop) circuit and each of the demultiplexers, completes the counting function of the flip-flops, in association with additional inputs on each of the demultiplexers interconnected in the counting circuit to provide the necessary sequencing of the demultiplexers. The several demultiplexer units, the 3 bit flip-flop counter, and the 4 bit binary counter used to advance all the demultiplexer units may be regarded as a two-stage demultiplexing means.

An additional pulse forming circuit is used to provide a suitable reset pulse after all of the demultiplexer units have each gone through one demultiplexing cycle.

The invention will be described further by way of example with reference to the accompanying drawings, wherein:

FIG. 1 is a diagram of a circuit according to the invention in which an array of 16 adjacent electrodes is operated through a demultiplexer with 16 outputs;

F lG. 2 is a diagram of a circuit in accordance with the invention in which five groups of 16 electrodes are operated through five demultiplexers, and

FIG. 3 is a graph showing pulses present in the circuits of FIGS. 1 and 2.

In FIG. 1 the electrosensitive paper used as the medium for graphical signal display is designated with the reference numeral 20. For writing information on the electrosensitive paper 20, there is provided a group 21 of 16 writing electrodes 8,, 8,, S S, which are arranged next to each other and electrically insulated from each other. These writing electrodes are respectively driven by writing transistors T,,, T,, T T,,, The collectors of the writing transistors are connected to the respective writing electrodes and their emitters are grounded, to the apparatus chassis, for example. The electrosensitive paper 20 is connected to the writing voltage of -35 volts over a resistor 26.

A demultiplexer 31 of the time-division type serves the electrode group 21. This demultiplexer is provided with 16 information outputs designated 0, 1, 2 and has four binary switching inputs A,, B,, C,, D, serving as tming information inputs and two enable inputs 6, and G The demultiplexer 31 can accordingly be a commercial type of TTL-demultiplexer built in accordance with integrated circuit techniques, such as the type SN 74154 made by Texas Instruments.

The NAND gates may likewise be provided in integrated circuit form with several on one substrate (e.g., SN 7400 made by Texas Instruments). The binary counter 50 used to step the demultiplexer 31 may likewise by a type SN 7493 Texas Instruments circuit unit. The monoflop 41 may be an SN 74121 device of the same series.

The SN 74154 units used as demultiplexers are TTL logic devices in which the selected output is at LOW" logic voltage level while all the others are at HIGH logic level provided that both of the enable (or strobe) inputs G, and G are likewise at LOW logic levl (otherwise the, selected output is at HIGH logic level, the same as the unselected outputs, which corresponds to no electrographic writing in the present apparatus). The LOW logic level could, for example, be 0.8 volts or less, and the HIGH logic level 2 or more volts, in a low impedance circuit.

The writing electrodes S 5,, S 8,, through individual transistors T,,, T,, T; .T,, which, since of black and one of white are involved, may in this case be of a switching" type. The information outputs l), 1, 2, 15 of the demultiplexer 31 are connected over protective resistors R R,, R R respectively to the bases of the writing transistors T,,, T,, T,, T,,.

A NAND gate N with two inputs E and E is provided, to the first input of which the signal to be dis played graphically is first supplied. The output P of the NAND gate N is connected to the input 41 ofa monostable flip-flop circuit 40, the output pulse of which has a variable period the length of which is adjustable by a potentiometer which is not shown in the drawing. The output 42 of the monostable flip-flop (monoflop") 40 is connected to the first enable input (1,, of the demultiplexer 31. The second input E of the NAND gate N is connected to the pulse input 51 of a 4 bit bi-.

nary counter 50, of which the information outputs A B C D are connected to the information inputs A,, B,, C,, D, of the demultiplexer 31 to advance the switching circuits of the latter. The second enable input G of the demultiplexer 31 is grounded and thus is held in LOW" condition. Finally a second monostable flip-flop circuit 60 is provided of which the noninverting output 61 is connected to the reset input 52 of the 4 bit binary counter 50. The reset control input of monoflop 60 may be derived from the counter 50, from the demultiplexer 31 or from an external timer.

The manner of operation of the circuit of FIG. 1 is as follows:

The information (VIDEO) to be graphically displayed on the electrosensitive paper is applied as a signal to the first input E,,,, of NAND gate N (FIG. 3, second line). At the second input E of NAND gate N a clock pulse 0, externally supplied to the circuit appears which also advances the 4 bit binary counter 50. The pulses appearing at the output P of NAND gate N are shortened in duration in monoflop circuit 40 to a value 1,,- corresponding to the switching time of each of the writing electrodes S 8 ,8 515, this value being adjustable by a potentiometer not shown in the drawing. This period t,,- of the pulses appearing at the output of monoflop 40 is so adjusted that it is shorter than the time in which the electrographic effect would come to an end by burnout.

If short pulses rather than long pulses are put out by the NAND gate N,,, which as previously discussed depends upon the polarity and duty cycle of the clock pulses and the polarity in which the output pulses are effective, then the monoflop 40 can operate as a pulse stretcher instead of as a pulse shortener, with the result in any event being the same. Furthermore, if the signals to be represented graphically are not two-valued, but are of various levels that are to be reproduced with gradation in the electrographic process, then the NAND gate N is not an ordinary digital gate but it is in effect a switched amplifier and the monoflop 40 switches on an amplifier or other device (not shown) during the length of its output pulse so that the output of the combined arrangement will have an amplitude corresponding to the signal at the input of the system and a pulse length determined by the setting of the monoflop 40. It is also possible to have the amplitude of the input signal very the duration of the pulse produced by monoflop 40, by means not shown, instead of the provision of the manual pulse length adjustment.

The pulses taken from the output of monoflop 40 are supplied to the signal input 0,, of demultiplexer 31, whereas the second signal input G is held in the LOW condition. The clock pulse c as already mentioned, advances the 4 bit binary counter 50, which is to say that it causes the outputs A B C D of the counter 50 to go through all 16 possible sets of binary conditions in logical sequence. These output count pulses of the 4 bit binary counter 50 are provided to the information inputs A,, B,, C,, D, of the demultiplexer 31, causing the switching circuits of the latter to be advanced as previously mentioned. In this way the information outputs 0, 1, 2, 15 of demultiplexer 31 are caused to produce one after the other in sequence as timed by the pulses present at the first input (3,, are switched to the LOW" condition for the period p of a single pulse. A writing pulse consequently appears only at the particular information outputs which, at that moment, receive a VIDEO signal with the necessary information to produce a pulse. The writing pulses transmitted from the information outputs 0, l, 2, 15 of demultiplexer 31 are led to the base electrodes of writing transistors T,,, T,, T, T,,, respectively over resistors R,,, R,, R R, After all of the writing electrodes have been connected in turn to the demultiplexer, the 4 bit binary counter 50 is reset to its original condition by a reset pulse, the duration of which is determined by monoflop 60.

FIG. 2 shows a second embodiment of the invention. For the graphic display of information on electrosensitive paper, there are here provided five adjacent electrode groups 21, 22, 23, 24, 25, each of which contains 16 writing electrodes arranged next to each other and insulated from each other. The writing electrodes of the first group 21 are designated S,, S, S those of the second group 22 are designated S S S S, and so on. The writing electrodes S,, S, S 5, of each group are controlled over writing transistors T,,,,, T,,,, T T, where the subscript i may take the value 1, 2, 3, 4 and 5 according to whether it refers to the writing electrode or to the writing transistor in the first group 21, the second group 22, the third group 23, etc. The collectors of the writing transistors are connected to the writing electrodes, while their emitters are grounded. The electrosensitive paper is connected to the writing voltage of ---35 volts over a resistor 26. Each of the five electrode groups 21, 22, 23, 24, is provided with one of the five identical demultiplexers 31, 32, 33, 34, 35. Each demultiplexer is provided with two signal inputs G, G and with four binary information inputs A,, 13,, C,, D,-, where the subscript i may take the values 1, 2, 3, 4, 5 according to whethr the demultiplexer is associated with the first electrode group 21, the second electrode group 22, and so on. Each of the demultiplexers also has l6 information outputs, in each case designated 0, l, 2 15. These information outputs are connected to the base of the respective writing transistors T,, T, T T,,, over the resistors R,, R, R R respectively.

The NAND gate N,, is provided with two inputs E and E The output P of the NAND gate N is connected to the input 41 of a monoflop 40 of which the output pulses have a variable pulse duration i which may be varied by adjustment of a potentiometer not shown in the drawing. The second input E of NAND gate N,, is connected to a clock pulse source (not shown) and to the pulse input 51 of a 4 bit binary counter 50, the information of which are designated A B C and D These information outputs are connected to the information inputs A,, 8,, C,-, D,- of all the demultiplexers 31, 32, 33, 34, 35, in which arrangement the output A, is connected with all the inputs A,- (i l to 5), the output 8,, is connected with all the inputs D,- (i= 1 to 5). the output C is connected with all the inputs C,- (i= 1 to 5) and the output D, is connected with all the inputs D,- (i=.l to 5).

Five NAND gates N,. N N,,, N, and N each with three inputs E, E E,, are provided in connection with each of the five demultiplexers 31, 32, 33, 34, 35. The outputs of these NAND gates are designated P,-, where i= l to 5. The first enable input G of the first deniultiplexer 3l is connected to the output P, of NAND gate N,. the first enable input G of the second demultiplexer 32 is connected to the output P of NAND gate N and so on. Each of the first inputs E, of the five NAND gates N,, N N N N is connected to the output 42 of monoflop 40.

ln this circuit three flip-flops F,, F, and F are provided. The input 70 of first flip-flop F, is connected to the output D,, of 4 bit binary counter 50. The input 80 of second flip-flop F is connected to the noninverting output Q, of first flip-flop F,. The input 90 of third flipflop F is connected to the noninverting ogtput Q of second flip-flop F The inverting output Q of third flip-flop F is connected to the second enable input G of fifth demultiplexer 35. The noninverting output 0,, of third flip-flop F is connected to the second enable inputs G G G and G of the remaining four demultiplexers 31, 32, 33, 34. The second input B 2f NAND gate N, is connected to the inverting output Q, of first flip-flop F,. The third input E of NAND gate N, is connected to the inverting output 6 of second flip-flop F The second input E of NAND gate N is connected to the noninverting output Q, of first flipflop F,. The third input E o f NAND gate N is connected to the inverting output 0, of second flip-flop F The second input E of NAND gate N is connected to the inverting output 6, of first flip-flop F,. The third input E of NAND gate N is connected to the noninverting output Q of second flip-flop F The second input E of NAND gate N, is connected to the noninverting output Q, of first flip-flop F,. The third input E of NAND gate N, is connected to the noninverting output 02 of second flip-flop F The second input E of NAND gate N is connected to the noninverting output 0 of third flip-flop F The third input E of NAND gate N is held in HIGH condition by connection to the supply voltage U A second monoflop is also provided. The noninverting output 61 of monoflop 60 is connected to the reset input 52 of the 4 bit binary counter 50. The inverting output 62 of monoflop 60 is connected to the reset inputs 71, 81, 91 of the three flip-flops F,, F and F3.

The reset control connection of monoflop 60 may be derived from multiplexer 35, from flip-tlop F or from an external timer or synchronizer (not shown).

The manner of operation ofthe circuit of FIG 2 is as follows:

The information (VIDEO) to be graphically displayed on electrosensitive paper is applied to the first input E, of NAND gate N,,. Such a VlDEO signal is shown in the second line of FIG. 3 by way of example. At the second input E2." of NAND gate N there is applied a clock pulse Cp which is also applied to the input of4 bit binary counter 50 to advance that counter. The pulses appearing at the output P of NAND gate N has their duration shortened in monoflop 40 to a value which corresponds to the switching interval r,- of each of the individual electrodes 8,, S,, S, 5, this value being adjustable by means of a potentiometer not shown in the drawing. This duration t of the pulses formed at the output 42 of monoflop 40 is so adjusted that it is shorter than the time that would end the writing process by burnout. These pulses taken from the output 42 of monoflop 40 are applied to the first inputs E, of the NAND gates N,, of which the outputs P, are connected to the first signal inputs G, of the demultiplexers.

The clock pulse Cp, as already mentioned, advances at the same time the 4 bit binary counter 50, so that at its information outputs A B C D all 16 possible output combinations are provided in logical sequence. These output pulses of the 4 bit binary counter 50 are supplied to the several parallel connected information inputs A,-, B,, C, and D, of the demultiplexers 31, 32, 33, 34, 35. If both of the signal inputs 0, and G of the demultiplexers were simultaneously in the LOW condition, then the information outputs 0, l, 2 l5 of the demultiplexers 31, 32, 33, 34 and 35 would each in sequence and in the red above the writing impulses be connected to the LOW condition for the duration t of a single pulse. The outputs of all demultiplexers would simultaneously be switched to LOW, and then all the l outputs, then all the 2 outputs and so on until what the sixteenth, all the outputs would be connected to LOW and then it would begin again with all the 0 outputs.

By means of the flip-flops F F and F however, the second signal inputs G of the demultiplexers are so switched that only one demultiplexer is free to accept signalsat any time. The signals appearing at the output pulses arising at the'information outputs 0, l, 2 15 of the ,demultiplexers' 31, 32, 33, 34, 35 are furnished over the protective resistances R R R R to the baseelectrodes of the respective writing transistors T ,-,'T, T 3, T which each in turn switch the writing voltage through to the electrode for the duration t,,- of the pulse. After all of the writing electrodes S S 8 S of all groups 21, 22, 23, 24 and 25 have been run through in sequence, in the illustrated case, therefore, after 80 clock pulses, all of the counters.50, F F F are reset to the initial condition by a reset pulse which has its duration defined by the operation of monoflop 60.

Theinvention has been described in connection with VIDEO signals ofa binary or two-valued kind, because in the illustrated case of metallized paper writing material the darkness of writing is difficult to control linearally with reference to pulse voltage, so that degrees of blackness are adjusted by the monoflop pulse duration rather than otherwise. Consequently, the driving transistors T T,, T T may be switching type transistors, since their function is to switch the writing voltage to the electrode or not according to whether 21 VIDEO signal is present or not during the period that the particular transistor is connected through to the monoflop pulse generator 40 through the demultiplexer. If there is no VIDEO signal present at the time of the corresponding clock pulse, the monopulse flip-flop 40 will electrode comb organization together with the corresponding driving transistors, protective resistors and the multiplexers and such an electrode comb can consist of individual segments if more than one demultiplexer is used, with one segment for the equipment as- 'sociated with each demultiplexer. The writing electrodes are preferably made of tungsten wire and they may very conveniently be provided by plating the end of thetungsten wire, which used to be connected to the transistor by electroplating with copper, gold, silver, tin or a combination of those metals and then soldering the plated end of the tungsten wire directly to the collector connection of the driving transistor with soft solder.

Although the invention has been disclosed with reference to specific embodiments, it will be understood that variations and modifications may be made within the inventive concept without departing from the spirit of the invention.

We claim:

1. The method of visually recording electrical information by means of a multiplicity of writing electrodes, arranged in a substantially linear array and electrically insulated from each other, on electrosensitive sheet material, which method comprises the steps of:

preparing information to be recorded in sequential form;

gating said information at intervals to produce a so quence of'pulses having a predetermined duration less than the shortest time required to produce local burnout on said sheet materialtherefrom, and

connecting individual electrodes of said array in succession, for time intervals longer than the duration of said pulses to a circuit supplying said sequence of pulses,

thereby energizing those electrodes so connected when one of said pulses is present and then only for the duration of said respective pulses.

2. The method of visually recording information by means of a multiplicity of writing electrodes, arranged next to each other and electrically insulated from each other, on electrosensitive sheet material the electrographic effect on which is limited by a localized burnout characteristic, which method comprises the steps of:

modifying information to be recorded into the form of information pulses of a duration less thanthe period in whichthe activation of one of said .electrodes would come to a stop by local burnout;

connecting said electrodes in time sequence to a source of information so modified at switching intervals greater than the duration of said information pulses,

thereby energizing those electrodes so connected when one of said pulses is present and then for the duration of said respective pulses.

3. The method of visually recording electrical information by means of a multiplicity of writing electrodes, arranged in a substantially linear array and electrically insulated from each other, on electrosensitive sheet material, which method comprises the steps of:

generating a sequence of clock pulses (c counting said pulses and driving with count indicating signals (A, B, C, D) thereby produced the distributive switching of a time-division demultiplexer applying said clock pulses and also electrical information to be recorded to gate means (N to produce gated pulses of said electrical information; applying said gated pulses, or pulses derived therefrom, to the signal input of said multiplexer; applying the distributed outputs of said demultiplexer respectively to the control electrodes of controlled semiconductor devices (To, T T and controlling the energization of said writing electrodes (S 8,, S respectively by means of said controlled semiconductor devices in such a manner as to energize said electrodes sequentially, and each only when one of said gated pulses is present and then only for the duration of such gated pulse.

4. A method as defined in claim 3 in which the modifying of the electrical information to be recorded comprises the steps of:

applying said clock pulses and electrical information to be recorded to said gate means (N to produce gated pulses of said information;

deriving, from said gated pulses, pulses of a different time length less than said burnout period, and applying said derived pulses to the signal input of said multiplexer.

5. Apparatus for displaying information on electrosensitive sheet material, the electrographic effect on which is limited by a localized burnout characteristic comprising:

an array of a multiplicity of adjacent writing electrodes electrically insulated from each other;

a clock pulse generator;

gate means (N for producing gated pulses timed by said clock pulses from a signal representative of information to be displayed; demultiplexing means (31) having a successive sequencing interval, determined by said clock pulse generation, at least as long as the time required to produce local burnout on said sheet material and including a binary counter (15) responsive to said clock pulses for distributing said pulses produced in response to operation of said gate means in sequence to the individual writing electrodes of said array, said gate means accordingly being the same for all pulses, and

circuit means incorporated in said gate means for assuring that the duration of pulses supplied to said demultiplexing means in response to operation of said gate means is less than the time required to produce local burnout on said sheet material.

6. Apparatus as defined in claim 5 in which said circuit means incorporated in said gate means is a monostable pulse forming means (40) of adjustable pulse length interposed between said gate means and said multiplexer.

7. Apparatus as defined in claim 5 in which a multiplicity of controlled semiconductor devices (T T T T are interposed between the outputs of said demultiplexing means (31) and the respective writing electrodes (5 8,, S 5, of said array to control the energization of said writing electrodes.

8. Apparatus for displaying information on electrosensitive sheet material, the electrographic effect on which is limited by a localized burnout characteristic, comprising:

an array of a multiplicity of adjacent writing electrodes electrically insulated from each other, said electrodes of said array being disposed in a plurality of sub arrays (21, 22, 23, 24, 25), each comprising the same number of writing electrodes (8 i, 8,,

II, S2, S15,

a clock pulse generator;

monostable gate means (N for producing, from a signal representative of information to be displayed, gated pulses timed by said clock pulse generator and having a duration less than the time required to produce local burnout on said sheet material;

plurality of functionally identical demultiplexers (31, 32, 33, 34, 35) timed by said clock pulse generation and respectively arranged to distribute said gated pulses in turn to each sub array (21, 22, 23, 24, 25) of said writing electrodes, each of said dcmultiplexers hiving two signal inputs and having individual gate means connected between a first signal input of said demultiplexer and the output of said monostable gate means, said individual gate means having a first input to which the output of said monostable circuit is connected and two additional inputs;

a resetting circuit; and

a plurality of flip-flop circuits are interconnected with each other, with the second and third inputs of said individual gate means and with the second inputs of said demultiplexers and also with said resetting circuit, so that each of said demultiplexers will be activated for a complete cycle of operation in sequence while the others of said demultiplexers are furnishing no output, whereby each one of said writing electrodes will be activated in turn.

9. Apparatus as defined in claim 8 in which one or more of said sub arrays of writing electrodes are mounted on an electrode comb consisting of individual segments which contain writing electrodes, driving semiconductor devices therefor, and demultiplexers.

10. Apparatus as defined in claim 9 in which the writing electrodes are made up of tungsten wires.

11. A method of making an apparatus for electrographically displaying formation in which the ends of the tungsten wires forming the writing electrodes of said apparatus which are to be connected to the respective driving semiconductor devices of said apparatus are electroplated with a metallic material selected from the group consisting of the metals copper, gold, silver, tin, and combinations of said metals as simultaneously electroplated, and are then affixed with the thus electroplated end soldered with soft solder to the collector connection of the corresponding driving semiconductor device.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US3441946 *Jun 29, 1965Apr 29, 1969Bendix CorpCircuit for supplying writing signals for use with electrosensitive paper recorders
US3553718 *Jun 20, 1969Jan 5, 1971IttMultiple stylus electrolytic recorder
US3611411 *Oct 29, 1969Oct 5, 1971Listening IncSpectrum-analyzing recorder
US3613103 *Jul 25, 1969Oct 12, 1971Alden Res FoundAnalog signal modifying apparatus
US3644931 *Sep 10, 1969Feb 22, 1972New Zealand Inventions DevMultistyli recorders with styli cyclically moved through interstylus spacing
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3947626 *Mar 27, 1974Mar 30, 1976U.S. Philips CorporationMethod of recording cinematographic images from an electric signal produced by scanning image sequences to be displaced and device for carrying out this method
US4100551 *Sep 9, 1975Jul 11, 1978Sci Systems, Inc.Rotary electrical printer and method
US4145697 *Dec 28, 1977Mar 20, 1979Honeywell Inc.Graphic recording apparatus with stylus addressing by shift registers
US4232342 *Jul 17, 1978Nov 4, 1980Skala Stephen FMultiplexing for facsimile systems
US4413269 *Nov 23, 1981Nov 1, 1983International Business Machines CorporationMethod of and apparatus for controlling gray scale while printing on charge sensitive recording mediums
US4470056 *Dec 29, 1981Sep 4, 1984International Business Machines CorporationControlling a multi-wire printhead
US4536769 *Mar 21, 1983Aug 20, 1985International Business Machines CorporationMethod of recording information on an electrosensitive record carrier
US4575740 *Mar 21, 1983Mar 11, 1986International Business Machines CorporationTransistor circuit for reducing current after ignition in a metal paper printer
US7730366 *Jun 30, 2004Jun 1, 2010Sony CorporationPhase error determination method and digital phase-locked loop system
US20050022076 *Jun 30, 2004Jan 27, 2005Shinobu NakamuraPhase error determination method and digital phase-locked loop system
EP0082978A1 *Dec 2, 1982Jul 6, 1983International Business Machines CorporationCircuit for controlling a multi-wire printhead
EP0096184A1 *Apr 13, 1983Dec 21, 1983International Business Machines CorporationMethod for controlling the energization of the print elements in an electroerosion printer
Classifications
U.S. Classification347/161, 358/425, 358/300, 347/162
International ClassificationG06K15/02, G06K15/10, H04N1/23, H04N1/04, G06K15/12, B41J2/425
Cooperative ClassificationH04N1/23
European ClassificationH04N1/23