5.4.7 Left-to-rightprinting
TheFX-850normallyprintsbidirectionally,withtheprintpositionmoving
alternatelyleft-to-rightand right-to-left.Cuttingdown printheadmotion
doesspeedup printingforthoseearlierstylesofprinter—thoughit hardly
compam withlaserprinting.
we problemwithbidirectionalprintingisthattheprintheadcangetslightly
out of alignment.When you’re using more primitive took sometimes
accuracymattersmorethanspeed,soa commandforplainoldleft-to-right
printing(sometimescalled “unidirectionalprinting”)is availableon Ep-
son’sprintem.
Thefollowingcommanddoesnothingto improvetheaccuracyof yourStar
LaserPrinter4, but it’s includedfor software compatibility’ssake. The
commandjustmovestheprintpositiontotheleftmargin,actingasacarriage
Mum withouta linefeed.Normalprintingresumeswiththenextcarriage
return.
To turnon left-to-rightprintingforjust oneline,this is the command:
<ESC><
5.4.8 Movinghorizontallyfromtheleft margin
Two horizontalmotioncommandssend the print positionto a particular
positionon theline.Thesecommandsarebasedon FX-850dots.Unfortu-
natelytheFX-850offersonly60or 120dotsperinch,ratherthanthe Star
LaserPrinter4’susualdensityof 300dots.So we’llexpressthesemovesin
termsof incrementsof 1/60or 1/120inch.
Onemovecommandisan“absolute”move,totherightfromtheleftmargin.
Theotheris a “relative”move,leftor rightfromthe currentprintposition.
To move from the left margin in incrementsof 1/60inch, you send this
command:
<ESC>$ d n2
Atthebeginningofthechapterwesaidsomecommandvariables,likenl and
n2 here, could representbytes to be addedtogether.This is one of those
commands.The nl representsunitsand n2 represents256-unitgroups.In
thismovecommand,the actualunitsare the 1/60inchincrements.
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