Ricoh LDD280 - 6.4 THERMAL HEAD

THERMAL HEAD
C262/C265 6-22 SM
6.4 THERMAL HEAD
6.4.1 SPECIFICATIONS
C262
• Length 303.42 +-0.1 (mm)
• Number of thermal head elements 7168
• Density of thermal head elements 600 dpi
C265
• Length 292.6 +-0.1 (mm)
• Number of thermal head elements 4608
• Density of thermal head elements 400 dpi
Thermal Head Control
The thermal head contains heating elements at a density of 600dpi:C262/400 dpi:
C265. The thermal heating elements melt the over-coating and polyester film layers
of the master, in accordance with the image signal for each pixel.
The PSU board applies power (VHD) to the thermal heating elements. The power
varies from one head to another since the average resistance of each element
varies. Therefore, when replacing the thermal head or power supply unit, it is
necessary to readjust the applied voltage to the specific value for the thermal head.
Thermal Head Protection
The thermistor on the thermal head provides thermal head protection, preventing
the thermal head from overheating when processing a solid image. The CPU
checks for any abnormal condition when the Start key is pressed; it displays an SC
code on the operation panel as follows:
SC Code Conditions
Detecting
Component
SC203
Over 54°C
Thermistor
SC202
Under - 20°C (Normally in this case, the thermistor is
open, or a related connector is disconnected.)
Thermistor
SC201
When the pulse width that controls the thermal head
energy becomes abnormal, master making stops and
generates this SC code.
ECU board
SC200
The CPU monitors the ID signal from the thermal
head, which identifies the thermal head type. If an
abnormal ID signal is detected just after installing the
master making unit in the machine, it generates this
SC code.
ECU board