4-1
CHAPTER 4
DRIVE METHOD
4.1 THERMAL HEAD DRIVE TIMING
4.1.1 In case of executing previous line history control
•
Preface
Input signals to the CTRL pin controls the driving of the previous line history control called pre-heat
and main heat.
BCLR should be normally “High”. “Low” forcifully clears the selected block.
•
Input of pre-heat pulse
Input of HDAT and HCLK transfer the print data to the shift register in serial input. “High” means
printing and “Low” means no-printing in HDAT. HDAT data is read in at the rising edge of the HCLK
inputs. Let CTRL go to “High” when inputting pre-heat pulse data. When inputting print data, only
“Low” data of dot in previous line turns to “High”, and is transferred to the shift register. The
transferred line of data is stored in the latch register by turning LATCH to “Low” after turning CTRL to
“Low”.
•
Input of main heat pulse
Let CTRL go to “Low” for input of main heat pulse data. Input the print data in the same way as pre-
heat pulse data.
•
Selection of the heat block
BDAT and BCLK input transfer the selected block data in serial input. “High” means selected and
“Low” means unselected in BDAT. BDAT data is read in at the rising edge of BCLK input. CTRL
should be kept “High”. 13 bits selected data input corresponding to the 13 blocks are transferred in
serial and the corresponded blocks are selected. The 1st input bit corresponds to the 1st block and
the last input bit corresponds to the 13th block .
•
Input of pre-heat pulse
Keep CTRL in “High”. “High” of DST drives heat elements of the thermal head in the blocks selected
by BDAT. Then, let DST go to “Low” after driving for the period calculated using the formula shown
in “2.6 CONTROLLING THE HEAD ACTIVATION (DST) PULSE WIDTH”.
•
Input of main heat pulse
Keep CTRL in “High”. “Low” of Latch stores main heat pulse data in the selected block by BDAT in
the latch register. “High” of DST drives the heat elements of the thermal head. Then let DST go to
“Low” after driving for the period calculated using the formula shown in “2.6 CONTROLLING THE
HEAD ACTIVATION (DST) PULSE WIDTH”.
Summary of Contents for LTP3445
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