Left-to-right printing
TheEX-800normallyprintsbidirectionally,withtheprintpositionmoving
alternatelyleft-to-rightand right-to-left.Cuttingdown printheadmotion
doesspeedup printingforthoseearlierstylesof printer—thoughithardly
compareswithlaserprinting.
Theproblemwithbidirectionalprintingisthattheprintheadcangetslightly
out of alignment.When you’re using more primitivetools sometimes
accuracymattersmorethanspeed,so a commandforplainoldleft-to-right
printing(sometimescalled“unidirectionalprinting”)is availableon Ep-
son’sprintem.
Thefollowingcommanddoesnothingto improvetheaccuracyofyourStar
LaserPrinter8, but it’s includedfor softwarecompatibility’ssake. The
commandjustmovestheprintpositiontotheleftmargin,actingasacarriage
returnwithouta linefeed.Normalprintingresumeswiththenextcarnage
return.
To turnon left-to-rightprintingforjust oneline,thisis thecommand:
<ESC><
Moving horizontally from the left margin
Two horizontalmotioncommandssend the printpositionto a particular
positionontheline.Thesecommandsarebasedon EX-800dots.Unfortu-
natelyiheEX-800offersonly60or 120dotsper inch,ratherthantheStar
LaserPrinter8’susualdensityof 300dots.Sowe’llexpressthesemovesin
termsof incrementsof 1/60or 1/120inch.
Onemovecommandisan“absolute”move,totherightfromtheleftmargin.
Theotheris a“relative”move,leftor rightfromthecurrentprintposition.
To move from the left marginin incrementsof 1/60inch, you send this
command:
<ESC>$ nl n2
Atthebeginningofthechapterwesaidsomecommandvariables,likenl and
n2 here, couldrepresentbytesto be addedtogether.This is one of those
commands.The nl representsunitsand n2 represents256-unitgroups.In
thismovecommand,theactualunitsarethe 1/60inchincrements.
107