Sony UP-890MD - Page 50

(ii)
The
data
is
input
to
IC103,
when
the
“0”
STB
pulse
synchronized
with
INT-V
is
input,
the
first
stair
data
is
sent
to
the
head
shift
register
section
synchronized
with
CLK.
(iii) When the “1"STB pulse is input, the lst stair data is transferred to the latch
section
and
the
2nd
stair
data
is
input
to
the
shift
register
section.
At
the
same
time,
the
DR
pulse
goes
“L”
and
the
“H”
data
among
the
data
input
as
the
first
stair
data
switches
on
the
corresponding
output
stage
transistors,
heating
up
the
corresponding
resistors.
The
“L”
data
switches
OFF
the
corresponding
output
stage
transistors
so
those
resistors
do
not
heat
up.
This
operation
is
carried
out
64
times.
If
“H”
data
is
sent
the
1
through
64
times,
the
resistors
generate
heat
the
entire
time
and
the
printing
is
the
blackest
possibie.
If
the
data
is
only
high
until
the
32
times,
the
printing
is
an
intermediate
stair.
This
is
how
intermediate
stairs
are
generated
by
sending
high
data
a
certain
number
of
times
and
generating.
heat
in
the
resistors
that
many
times.
(iv)
Thus,
by
controlling
the
time
until
the
next
data
is
transferred
to
the
latch,
the
darkness
of
intermediate
stairs
can
be
achieved
simply.
In
other
words,
intermediate
stair
darkness
can
be
controlled
by
changing
the
STB
intervals,
To,
Ti,
Tz,
Tz,
Ty
+
Tes,
Ta.
Specifically,
IC301
matches
the
intervals
Ti
to
Tu
to
the
paper’s
7
characteristic
(the
degree
of
darkening
relative
to
the
heat
applied).
This
is
called
characteristic
control.
(v)
If
the
DR
pulse
is
also
controlled
as
described
in
5-6-3,
even
fine
stair
can
be
expressed.
*
Note:
The
section
in
@
is
generated
when
the
STB
pulse
T
interval
is
26sec.
(The
STB
pulse
T
interval
is
a
minimum
of 26
psec.)
Thus,
this
unit
provides
smooth
expression
of
intermediate
stairs
by
controlling
the
STB
pulse
T
interval
and
the
DR pulses.
5-6-5. Temperature compensation
As
explained
in
5-6-4,
intermediate
stairs
are
expressed
by
controlling
the
STB
pulse
T
interval
and
the
DR
pulses,
but
since
the
energy
required
to
make
thermosensitive
paper
turn
color
varies
with
the
room
temperature
and
with
the
heat
generated
by
and
built
up
in
the
printing
head
during
continuous
printing.
This
unit
has
a
built-in
thermistor
(CN101-©,@)
IC301
measures
the
change
in
the
head
temperature
and
to
compensate
for
temperature
change
controls
the
STB
pulse
T
interval
and
the
DR
pulse,
just
as
is
done
for
stair
generation.
Specifically,
when
the
temperature
rises
it
reduces
the
STB
pulse
T
interval
and
the
DR
pulses,
but
when
the
temperature
falls,
it
increases
the
STB
pulse
T
interval
and
the
DR
pulses.
—58—