Service manual

5-6 DECcolorwriter 1000
5 Theory of Operation
Engine control board block description
The engine control board receives color bitmaps from the image processor board. It also
controls the print engine's printing process, including all motors, sensors, and the thermal
head. The block diagram shown in Figure 5-2 illustrates the functional operation of the
print engine control board. The block diagram consists of nine major functions:
n Central processing unit (CPU)
n Interface
n Data controller and data buffer
n Timing controller
n Dot compensator
n Head controller
n Thermal head
n Mechanical controller with motors, solenoids, and sensors
n Internal test pattern generator
Figure 5-2. Print engine board block diagram
8699-09A
Thermal
head
Image
processor
Interface
buffers
Line
buffer
Heat
control
(dot compen-
sation)
Line
memory
buffer
Test
pattern
generater
CPU
Thermal head
controller
Mechanical
controller
Engine control board
Sensors
From
host
computer
Motors
Solenoids