Sony UP-D897 - 3-4-3. Temperature Correction; 3-4-4. Correction of Resistor Count

3-4-3. Temperature Correction |
The print energy required for thermosensible paper
changes moment by moment due to the heating and
thermal storage of a thermal head during change in room
temperature or continuous printing. Therefore, the
corresponding correction is required. In this unit, IC202
measures the temperature change of a thermal head from
the internal thermistor of the thermal head: IC202 then
converts the temperature change into 8-bit head
temperature data and corrects the change in concentration
for the. temperature on which gamma characteristics were
reflected. The concentration change can be corrected by
controlling the width of a STB pulse.
3-4-4. Correction of Resistor Count
The total current flowing through a thermal head differs in
the state where the resistors of the thermal head are all turn
on or partially turned on. Therefore, an error occurs in the
energy applied to each resistor. When print is made
without correcting an error, a stripe occurs in the print
result at the point where the number of resistors in which a
thermal head is turned on changes rapidly. A circuit that
corrects this stripe is incorporated into IC202.
3-4
UP-D897