Line-writing apparatus with plural print heads in parallel rows
United States Patent 11 1 Hurst 5] Apr. 1, 1975 1 LINE-WRITING APPARATUS WITl-l 3,541,956 7/1967 Falcherd et al mm x 3,708,050 1/1973 McCarthy 197/1 R PLURAL PRINT HEADS [N PARALLEL ROWS Inventor: Kurt Hurst, Stuttgart, Germany Assignee: Robert Bosch GmbH, Stuttgart,  
 Germany Filed: May 11, 1973 Appl. No.: 359,559  
  Foreign Application Priority Data May 31, 1972 Germany 2226394 US. Cl 197/1 R, 101/9305, 197/5 Int. Cl B4lj 3/54 Field of Search 197/1, 18, 48, 49, 55,  
 References Cited UNITED STATES PATENTS Zint 197/90 UX Schiebeleru......................... 197/1 R Fitchet [97/1 R Primary Examiner-Edgar S. Burr Assistant Examiner-R. T. Rader Attorney, Agent, or Firm-Michael S. Striker 57] ABSTRACT A strip-shaped record carrier having two oppositely extending longitudinal margins is advanced in its direction of elongation. A pair of scribing units are located at opposite lateral sides of the carrier, and the drive is provided for moving these units in unison and in mutually opposite directions in such a manner that as one unit traverses the record carrier from one to the other margin thereof, the second unit will traverse the record carrier from the other to the one margin thereof, and the two units will reach the respectively opposite margins at the same time. The units are spaced longitudinally of the record carrier by a distance corresponding to the spacing between two consecutive lines which are to be recorded on the carrier.  
 12 Claims, 4 Drawing Figures PATENIEBAPR H975 3.874.492  
 SHEET 1 0F 3 Fig. 1  
 LINE-WRITING APPARATUS WITH PLURAL PRINT HEADS IN PARALLEL ROWS BACKGROUND OF THE INVENTION The present invention relates to a line writing apparatus. and more particularly to a high-speed linewriting apparatus for making recordings on a moving strip shaped carrier.  
  It is known in the prior art to provide electrically operated line writers having one or more writing or scribing heads or units each of which carries a plurality of electrically actuated writing electrodes which are insulated from one another. The head or heads move over a strip-shaped record carrier and as selected ones of the electrodes are energized, they will burn away a portion of the record carrier surface to produce therein an indicium composed of a plurality of dots each of which is produced by one of the energized electrodes. Successive recording of such indicia then produces a line of indicia,  
  It is also known from the prior art to provide a line writer ofthe general type in question which utilizes two writing heads which together and simultaneously form the indicia of a line. The two scribing units are mounted on a common drive spindle and each traverses the width of half the line, that is, they move between the middle of the line and one of the ends thereof. They move in counter direction, so that they meet at the middle ofthe line. The trouble with this arrangement is that as the two scribing units meet at the middle of the line they ofcourse interfere with each other, resulting in the necessity for leaving a free space at the middle of the line. Moreover. although the drive spindle used, a socalled Napiers Spindle, can move the scribing units from the respective ends of the line to the middle, it  
 cannot return them so that a second spindle of the same type must be provided for this purpose.  
 SUMMARY OF THE INVENTION It is, accordingly. a general object of the present invention to provide an improved apparatus of the character described herein, which avoids the disadvantages of the prior art.  
  More particularly it is an object of the invention to provide such an improved apparatus which permits the high speed formation of lines of indicia on a stripshapetl moving record carrier, so that the lines extend transversely of the direction of advancement ofthe carrier.  
  In keeping with these objects, and with others which will become apparent hereafter, one feature of the invention resides, in an apparatus of the character described, whose purpose is to produce transversely extending parallel lines of indicia on a longitudinally moving strip shapcd record carrier having two opposite longitudinally extending margins. a combination which comprises mounting means spanning the record carrier transversely of the path of movement thereof. The combination further comprises a first and a second indicia-scribing unit carried by the mounting means and movable thereon transversely of the aforementioned path. The units are spaced longitudinally ofthc path by a distance corresponding to the spacing between two consecutive ones of the lines to be produced. Drive means is provided for moving the units in mutually opposite directions and at such speed that the second unit traverses the distance from one to the other of the margins by the time the first unit traverses the distance from the other to the one margin, and vice versa.  
  Thus, one unit always serves to write or scribe the indicia which make up a complete line. During the time required for this one unit to produce this line of indicia the other unit moves in counter-direction to the firstmentioned unit, and by the time the first unit reaches the end of the line which it has scribed, the other unit will have reached the beginning of the next line so that it is ready to start forming the indicia of this next line while the first unit is now being returned in direction opposite to its previous movement and to that of the second unit.  
  It is particularly advantageous if the scribing units are each mounted on a carriage which is guided along mounting means, such as for instance at least one guide rod spanning the entire width of the record carrier. The two units are advantageously driven by a common drive utilizing an elongated flexible element which forms a closed loop and is trained about two rollers located at opposite lateral sides of the record carrier.  
  The novel features which are considered characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will best be understood from the following description of specific embodiments when read in connection with the accompanying drawing.  
 BRIEF DESCRIPTION OF THE DRAWING FIG. I is a somewhat simplified front view of an apparatus according to the present invention;  
 FIG. 2 is a top-plan view of FIG. 1;  
  FIG. 3 is a simplified fragmentary side view of the apparatus shown in FIGS. I and 2; and  
  FIG. 4 is a diagrammatic illustration of a drive for the scribing units, utilizing a cord.  
 DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. I-4 illustrate an exemplary embodiment of an apparatus according to the present invention. As seen, the apparatus utilizes a frame having a base plate 10, one side portion II and an opposite side portion 12. Reference numeral 13 designates a record carrier which is strip-shaped and is advanced in the direction of its elongation by a roller 14. The lines of indicia are to be inscribed on the record carrier transversely to the path of movement thereof, that is from left to right, or vice versa, in FIG. 2. Record carriers of this type, carrying on their surface a coating which can be burned away by contact with a heated electrode, are well known in the art and require no detailed discussion,  
  There is further provided mounting means and guide means. This mounting means is in form of rods 15 and 16 on the one hand, and I7 and 18 on the other hand, all of which are secured to the side portions II and 12 of the frame. They thus extend in parallelism with the base plate 10, as is particularly clearly evident from FIG. I. A carriage I9 is mounted for movement along the rods 15 and 16 and carries a first scribing unit 2]. and a second scribing unit 22 is mounted on a carriage 20 which is supported by the rods [7 and 18. Thus, the two carriages I9 and 20 with their respective scribing units 21 and 22 can move along their guide rods 15 and 16, and 17 and 18, respectively, in direction transverse to the elongation of the record carrier 13.  
  A common drive is provided in this embodiment for both of the carriages 19 and 20. This drive, which is shown in more detail in FIG. 4, utilizes an elongated flexible element 23 which forms a closed loop and in H0. 4 is a cord. However, it could also be a tape, a belt or a toothed belt. In any case, the carriages 19 and are secured to the element 23 which is trained about two rollers 24 and located at opposite lateral sides of the record carrier 13 so that the element 23 forms two runs, with the carriage 19 being secured to the element 23 at one run thereof and the carriage 20 at the other run. This is clearly shown in FIG. 4 where it will also be seen that the roller 25 is driven by a diagram matically illustrated known step motor 26. Of course. the drive is such that when the carriages 19 and 20 reach the end position shown in FIG. 4 the direction of the drive is reversed until the positions of the carriages 19 and 20 are reversed from those shown in FIG. 4. Then, the drive is again reversed. in the embodiment of FIG. 4 the roller 25 is configurated as a threaded spindle and the element 23 has two free ends one of which is secured to the spindle in the region of one end thereof, and the other of which is secured to the spindle in the region of the other end thereof. as shown. Thus, when the roller 25 is rotated by the step motor 26, the element 23 whose end portions are located in the threads of the roller 25, is wound onto the roller 25 at one end thereof and at the same time wound off the rol ler 25 at the opposite end thereof. This is reversed when the rotational direction of the roller is reversed. With such a construction any slip of the element 23 with reference to the rollers 24 and 25 is positively prevented.  
  Coming to FIG. 3 it will be seen that reference numeral 27 designates a further roller, a so-called counterclectrode, which presses the carrier 13 against the roller 14 and also serves to complete the electrical circuit through the electrodes of the units 20 and 21 (the electrodes are diagrammatically shown in FIG. 3) and from the record carrier 13. In FIGS. 1 and 2 there is shown a starting position in which the unit 21 is located at the left-hand side, that is at the beginning of a line to be scribed. At this time the unit 22 is at the righthand side, that is at the end of an as yet unseribed line. The units 21 and 22 are each mounted on an arm 28 which is pivotably secured to the respective carriages 19 and 20. A pair of tension springs 29 is provided, each of which is connected with the respective arm 18 and the associated carriage 19 or 20. Thus, the arms 28 are pivoted by the springs 29 in a sense requisite for urging the writing electrodes of the units 21 and 22 against the surface of the carrier 13.  
 In addition, each of the two carriages 19 and 20 is provided with a bolt-shaped member. These members are identified with reference numerals 30 and 3011, respectively, and are so mounted on the carriages 19 and 20 that they can be shifted in the direction of movement ofthe carriages and opposite thereto. Each of the members 30 and 30a is provided with an essentially sawtooth-shaped kcrf31 and cooperates with a respective second bolt-shaped member 32 and 32a, respectively. The members 32 and 32:: extend normal to the members 30 and 3011, respectively, and as the latter members are shifted the front portions ofthe members 32, 32:! which extend into the respective kerfs, are  
 pushed out of these kerfs so that the members 32, 320 are displaced longitudinally away from the respective members 30, 30a. The ends of the members 32, 32a which are remote from the members 30, 3011 then push against the arms 28a of the members 28. The members 30, 30a cooperate with respective abutments 33, 34 which are located at the left side portion 11 and the right side portion 12; respectively.  
  When the apparatus is in the starting position shown in FIGS. 1 and 2, the bolt 30a of the carriage 20 has been shifted to the left, as a result of its contact with the abutment 34 as the carriage 20 moves to the final position shown in the drawing. This has caused the member 320 to be pushed out of the l-terf31 and to press against the arm 28a, thereby lifting the scribing unit 21 off the carrier 13.  
  When the apparatus is in use, both ofthe carriages 19 and 20 are moved in unison but in mutually opposite directions. As a result of this, the carriage 19 and the unit 21 are moved from left to right and the unit 2] will scribe the first line of indicia during such movement. As this takes place, the second carriage 20 and its associated head 22 are moved front the right to the left, to the beginning of the second yetto-be-scribed line. As  
 the carriage 21] reaches the left-hand position, its bolt 301: contacts the abutment 33 and is therefore displaced towards the right so that the member 32a can enter into the kerf 31 again and the unit 22 is urged back against the record carrier 13 under the influence of the associated spring. Thus, the second scribing unit 22 is immediately ready to start scribing the second line, during which step the first scribing unit 21 is returned towards the left-hand starting position shown in FIGS. 1 and 2. Now, and before the unit 21 can scribe the third line, the carrier 13 is advanced longitudinally by a distance corresponding to two lines, with the aid of a further step motor which is not illustrated but is entirely conventional.  
  The scribing units 21 and 22 may each be provided with a plurality of scribing electrodes, e.g., five rows of seven electrodes or seven rows of live electrodes, so that each unit can form a grid of thirty-five dots. Of course only selected ones of the electrodes will be energized to form the configuration ofa particular indicium which is to be inscribed. This is entirely conventional, as is the construction of the record carrier 13 which has a thin metal coating and which is burned away in the form of dots to form the respective indicium. A coding disk 35 is mounted on the shaft of the step motor 26 and determines via a light-beam arrangement the energization of the electrodes for the particular to be scribed. It is not novel and forms no part of the invention per se. Current for the electrodes of the units 21 and 22 is supplied via respective ribbon cables 36 which in the illustrated embodiment would have seven conductors, corresponding to the rows of electrodes.  
  it will be understood that each of the elements described above, or two or more together. may also find a useful application in other types of constructions differing from the types described above.  
  While the invention has been illustrated and described as embodied in a line-writing apparatus, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit ofthe present invention and the basic concepts thereof.  
  Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that from the standpoint of prior art fairly constitute essential characteristics of the generic or specific aspects of this invention and. therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.  
  What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims.  
  I. In an apparatus for producing consecutive parallel lines of indicia on a major surface of an elongated stripshaped record carrier having edges extending in the longitudinal direction of the record carrier, a combination comprising two scribing units; means mounting said scribing units so that one of said scribing units is permanently spaced from the other one in said longitudinal direction of record carrier by a distance corresponding to the spacing between two consecutive lines of indicia to be produced, said mounting means being elongated and extending transversely of the record carrier and parallel to the major surface thereof, said scribing units being mounted on said mounting means for displacement longitudinally thereof between a first end position adjacent one of the edges of the record carrier and a second end position adjacent the other edge; drive means for displacing one of said scribing units between said first and second end positions thereof and for simultaneously displacing the other scribing unit between said second and first end positions thereofi and vice versa, while said scribing units are always spaced by said distance in said longitudinal direction of the record carrier; means for actuating said scribing units so as to produce a respective line of indicia at least during the displacement of the respective scribing unit between said first and second end positions thereof: and means for effecting intermittent relative displacement between the record carrier and said mounting means in said longitudinal direction of the record carrier.  
  2. A combination as defined in claim I. wherein said drive means comprises a drive arrangement common to said units and operative for moving the same in unison 3. A combination as defined in claim 1; further comprising a pair of carriages mounted on said mounting means for movement longitudinally thereof; and wherein each of said units is carried by one of said carriagcs.  
  4. A combination as defined in claim 3, wherein said mounting means comprises at least two guide rails; and wherein each of said carriages is mounted on a different one of said guide rails.  
  5. A combination as defined in claim 1. wherein said drive means comprises a pair of rollers mounted adjacent the respective edges, and an elongated flexible drive clement trained about said rollers and forming a closed loop, said units being connected to said drive element.  
  6. A combination as defined in claim 5. wherein said drive element is a rope.  
  7. A combination as defined in claim 5, wherein said drive element is a tape.  
  8. A combination as defined in claim 5, wherein said drive element is a toothed belt.  
  9. A combination as defined in claim 5, wherein one of said rollers is provided with a thread, said drive element further comprising a rope trained about said one roller so as to enter into said thread; and wherein said drive means further comprises a step motor connected with said one roller for driving the same in rotation.  
  10. A combination as defined in claim 3; and further comprising pivot means mounting said units on the respective carriages for pivotal movement into and out of contact with said record carrier.  
  H. A combination as defined in claim I; and further comprising control means for moving each of said units into contact with said carrier upon the respective unit reaching said first end position, and out of contact with said carrier upon the same unit reaching said second end position.  
  12. A combination as defined in claim ll. wherein said units each comprise a member which is slidablc between two positions in which it effects movement of said unit into and out of contact with said carrier; and wherein said control means comprises abutments provided in the regions of said edges and operative for engaging and sliding the respective member from one to the other of said positions.