High speed printer

Abstract

A high speed line printer having a number of sets of hammers; one hammer for each character position defining a line of print, which coact with a moving type band. Each hammer time shares one of a number of drive circuits with others of the hammers in a set. A line may be printed in the time that a type font on the band moves past any particular character position.

What is claimed is: 
     
       1. An impact printer comprising a continuously moving type carrier with a number of characters thereon defining at least one type font, a plurality of sets of impacting hammers, .Iadd.each hammer having a position within one of said sets, the hammers in like positions among the sets being simultaneously in alignment with respective ones of said characters, .Iaddend.said hammers being adapted to be moved from a cocked position to an impact position, the total number of hammers equal to the number of character positions defining a line of print, each line of print being applied sequentially, holding means for maintaining each of said hammers in said cocked position, releasing means coupled to each of said holding means and responsive to activation thereof for selectively releasing each hammer to said impact position to coact withsaid carrier and thereby impacting a print medium, each hammer having a predetermined flight time from said cocked position to said impact position, a plurality of .Iadd.time-shared hammer .Iaddend.drivers .Iadd.in one to one correspondence with said hammer sets .Iaddend.coupled to said releasing means for selective activation thereof by application thereto of a release pulse said release pulse being of substantially less duration than said hammer flight time, means for coupling each said driver to various ones of said releasing means during each said line print sequence .[.for supplying.]. .Iadd.and adapted to supply.Iaddend.a plurality of sequential release pulses from .[.at least one.]. .Iadd.each .Iaddend.driver to a plurality of releasing means .Iadd.respectively associated with the hammers of the set corresponding to said driver, .Iaddend.during a single hammer flight time, .Iadd.release pulses being simultaneously applied to release means associated with hammers occupying like positions in different sets, .Iaddend.a first sensing means responsive to said character type and coupled to a character code generator, a memory containing sequences of desired character information, a comparator, said comparator responsive to said memory and said character code generator and coupled to said drivers for selectively actuating said drivers to release hammers in accordance with said sequences of desired character information, a plurality of fiduciary marks on said type carrier, second sensing means responsive thereto, a timing means responsive to said second sensing means for providing timing pulses, and means coupling said timing pulses to said comparator and said driver for synchronizing operation thereof in accordance with character position relative to hammer locations. 
     
     
       2. The printer of claim 1 further comprising: magnetic means for restraining said hammers against movement when in said cocked position.   
     
     
       3. The printer of claim 2 wherein said magnetic means is a permanent magnet. 
     
     
       4. The printer of claim 3 wherein said release means comprise electrical coils wound about said magnets. 
     
     
       5. The printer of claim 4 wherein said release means further comprises: means to pass a current through said coils to create a magnetic force in opposition to the magnetic force of said magnets.   
     
     
       6. The printer of claim 1 wherein the spacing between type characters on said carrier is different from the spacing between character positions on said line. 
     
     
       7. The printer of claim 6 wherein the spacing between type characters is greater than the spacing between character positions. 
     
     
       8. The combination of claim 1, wherein said character code generator comprises a character counter having an output coupled to said comparator, a preset means responsive to said second sensing means for resetting said character code counter, a variable delay means responsive to said first sense means and coupled to said character code counter by an increment by one device, and a decremental device coupling said second means to said character code counter, said decremental device reducing the input character count to said character code counter by the frequency at which hammers and characters are in registration. 
     
     
       9. The combination of claim 1, wherein said character code generator responds to said second sensing means and is set in response to a fiduciary mark, and responds to said first sensing means by stepping a count of one for each sensed character mark, whereby said character generator is kept current with movement of said carrier. 
     
     
       10. An impact line printer comprising a continuously moving type carrier with a number of characters thereon defining at least one type font, a plurality of sets of impacting hammers, .Iadd.each hammer having a position within one of said sets, the hammers in like positions among the sets being simultaneously in alignment with respective ones of said characters, .Iaddend.said hammers being adapted to be moved from a cocked position to an impact position, each line of print being applied sequentially, said hammer centers being positioned closer together than said type characters, said hammers operative by release of stored kinetic energy retained by said cocked hammers, holding means for maintaining each of said hammers in said cocked position, releasing means coupled to each of said holding means and responsive to activation thereof for selectively releasing each hammer to said impact position to coact with said carrier and thereby impacting a print medium, each hammer having a predetermined flight time from said cocked position to said impact position, a plurality of .Iadd.time-shared .Iaddend.drivers .Iadd.in one to one correspondence with said hammer sets .Iaddend.coupled to said releasing means for selective activation thereof by application thereto of a release pulse, said release pulse being of substantially less duration than said hammer flight time, means for coupling each said driver to various ones of said releasing means during each line print sequence .[.for supplying.]. .Iadd.and adapted to .Iaddend.a plurality of sequential release pulses from .[.at least one.]. .Iadd.each .Iaddend.driver to a plurality of releasing means .Iadd.respectively associated with the hammers of the set corresponding to said driver, .Iaddend.during a single hammer flight time, .Iadd.release pulses being simultaneously applied to release means associated with hammers occupying like positions in different sets, .Iaddend.a first sensing means responsive to said character type and coupled to a character code generator, a memory containing sequences of desired character information, a comparator, said comparator responsive to said memory and said character code generator and coupled to said drivers for selectively actuating said drivers to release hammers in accordance with said sequences of desired character information, a plurality of fiduciary marks on said type carrier, second sensing means responsive thereto, a timing means responsive to said second sensing means for providing timing pulses, and means coupling said timing pulses to said comparator and said driver for synchronizing operation thereof in accordance with the position of a character relative to a hammer location. 
     
     
       11. An impact line printer comprising a continuously moving type carrier with a number of characters thereon defining at least one type font, a plurality of sets of impacting hammers, .Iadd.each hammer having a position within one of said sets, the hammers in like positions among the sets being simultaneously in alignment with respective ones of said characters, .Iaddend.said hammers being adapted to be moved from a cocked position to an impact position, holding means for maintaining each of said hammers in said cocked position, releasing means coupled to each of said holding means and responsive to activation thereof for selectively releasing each hammer to said impact position to coact with said carrier and thereby impacting a print medium, each hammer having a predetermined flight time period from said cocked position to said impact position, a plurality of .Iadd.time-shared .Iaddend.drivers .Iadd.in one to one correspondence with said hammer sets .Iaddend.coupled to said releasing means for selective activation thereof by application thereto of a release pulse, said release pulse being of substantially less duration than said hammer flight time period, means for coupling each said driver to various ones of said releasing means during each line print sequence .[.for supplying.]. .Iadd.and adapted to supply.Iaddend.a plurality of sequential release pulses from .[.at least one.]. .Iadd.each .Iaddend.driver to a plurality of releasing means .Iadd.respectively associated with the hammers of the set corresponding to said driver, .Iaddend.during a single hammer flight time period, .Iadd.release pulses being simultaneously applied to release means associated with hammers occupying like positions in different sets, .Iaddend.a first sensing means responsive to said character type and coupled to said drivers for selectively actuating said drivers to release hammers in accordance with desired character information, a source of sequential timing signals, second sensing means responsive to said timing signals, a timing means responsive to said second sensing means for providing timing pulses derived from said timing signals, and means coupling said timing pulses to said drivers for synchronizing operation thereof in accordance with the position of a character relative to a hammer location. 
     
     
       12. The combination of claim 11, wherein each said release pulse duration is less than one quarter of the average hammer flight time. 
     
     
       13. The printer of claim 11 further comprising: magnetic means for restraining said hammers against movement when in said cocked position. 
     
     
       14. The printer of claim 13 wherein said magnetic means is a permanent magnet. 
     
     
       15. The printer of claim 14 wherein said release means comprise electrical coils wound about said magnets. 
     
     
       16. The printer of claim 15 wherein said release means further comprises: means to pass a current through said coils to create a magnetic force in opposition to the magnetic force of said magnets.   
     
     
       17. The printer of claim 11 wherein the spacing between type characters on said carrier is different from the spacing between character positions on said line. 
     
     
       18. The printer of claim 17 wherein the spacing between type characters is greater than the spacing between character positions. .Iadd. 19. A printer according to any of claims 1, 10, or 11, where the hammers in each set are adjacent one another. .Iaddend.