Epson TM200 - Page 22

TM200 Service Manual
- 20 -
Printer Mec hanism
Thermal head Module
T he the r mal head is d e sig ned so it s heat i ng el em e n t i s posi ti oned wher e it comes i nto
cont
act wi th t he p l at en. T he r o ll pa per wrap ped ar ound th e pl ate n is k e pt in cont act
wit h the ther m a l hea d ’ s heat i ng el em e n t at a p r escr ibed pr essure, and pr int i ng is
p
e rfor med whe n heat is g enera t ed b y the heat i ng element .
P
r i n ti ng is p e rf orm e d a cc o rd in g t o th e fo ll ow i n g st e p s:
1. T he pr int sig n al send s a pr escri b e d ene rgi zi ng p u lse to t he el ect rod e s tha t
co
rr espond to ea ch d o t t o be pr int e d .
2. Resist ors a t ea ch el ectro d e gener at e heat .
3. T he heat ener gy g ener ated by t he resisto r s i s tr ansmit ted to the r o ll p a per sur f a ce
t
h rou g h t he pr ot ecti v e lay e r t o t he pa per ’ s he at-sensi t i v e lay e r, c ausi n g co lor a ti on
o
f the p a p e r.
F i g u re 2 .2 F r ame cove r open
Th e p a p e r o u t l e t o f th e p r i n te r is c overe d , an d ev e n if p a p e r o u t pu t be c o m e s bl o c ke d f o r
so
m e r e ason, ther e i s en ough ro om in t he sp ace b e t w een the pl aten and fr ame cov e r for
acc
u mula ti on of t w o o r t h ree n o rmal le ngth recei pt s (the leng th o f one sheet is a ssum e d
t
o be 80mm or le ss ). T h is r e d u ces the chance of rece ip t p a per b e coming b e nt an d of t he
p
r i n t p i t ch becomin g unev en. Pa per tha t ac cumula tes c a n be easi ly pul l ed ou t of t he
p
r i n ter afte r t he pa per outlet is o p ened .