4.MOTORANDGEARTRAINASSEMBLY
4.1Themotorandgeartrainassemblydrivesthefollowing:
(a)beltassembly,whichproducestheprintoutimage,
(b)
paperfeed
roller,
which
moves
the
paper
upwards
as
printing
proceeds,
(c)encodingdisc,whichfunctionsinconjunctionwiththecontrol
electronicsp.c.boardtoprovidetheprintoutsignalstothe
stylf onthebeltassembly.
4.2Thehorizontallymountedmotordrives,viabevelgearing,the
vertically
mounted
pulley
and
wormshaft
which
rotates
the
belt
assembly.Thiswormshaftdrivesa horizontallymountedwormshaft
which,inturn,drivesthepaperfeedrollerassembly.Atthelower
endofthepulleyandwormshaft,a spurgeardrivestheencoderdisc,
bothitemsbeingmountedwithintheundersideofthebaseframe.
5.CONTROLELECTRONICSBOARD
5.1Thecontrolelectronicsboardismountedontheuppersurfaceof
thebaseframe.Inconjunctionwiththeencodingdiscandthe
LED/photodiodecombination,theboardprovidessignalstodrivethe
motorandtheprintingsystem.Thep.c.boardisconnectedto
thedouble-sidededge-connectorbya shortloom;thep.c.board-end
oftheloomisclampedbetweenthetopcoverandthebaseframewhen
thecoverissecuredtothebase.
6.BASEFRAMEASSEMBLY
6.1Thebaseframeassemblycomprisesthebaseframeandthebaseframe
insert,
both
of
which
are
plastic
mouldings.
The
base
frame
provides
a
chassis
on
which
most
components
are
mounted;
the
base
frame
insert
isa removablesectionwhichfitsintotheundersideofthebase
frame.Theinsertcontainsthelowerbushesfortheshaftsofthe
drive
and
idler
pulleys,
as
well
asthe
mounting
forthe
LED.
Itis
securedtothebaseframebytwoofthefourscrewswhichretainthe
topcover,andbytwoshorterscrews(seeFigure3).
7.PAPERREELCARRIERASSEMBLY
7.1Thepaperreelcarrierassemblyconsistsofa plasitcmouldingwhich
housesthereelofelectro-sinsitivepaper,anda spring-loadedpinch
roller.Thepaperissupportedinthecarrierontwoplastic
spigotted
end-caps
which
are
inserted
into
the
ends
ofthe
tube
atthe
centreofthereel; theseend-capsshouldbetransferredtothenew
reel
when
the
reel
is
changed.
The
spring-loadedpinch
roller
forces
the
paper
into
contact
with
the
paperfeed
roller
to
provide
the
'grip'necessarytoenablethepapertobefedthroughtheprinter.
The
complete
assembly
slides
into
the
base
frame,
and
clips
into
place;itisreleasedbypressurebeingappliedtothepointmarked
PRESS
HERE
onthe
underside
ofthe
carrier.
2.2
