Scanner controller circuit The CPU on the SCB controls the operation sequences of the scan engine. When the dc power is supplied to the scanner controller, the CPU starts to control the scan engine. When the scan engine is in standby status, the CPU outputs signals to drive each load of charge-coupled devices (CCDs), motors, solenoids, and scanning lamps based on a scan command from the CPB. CPU (IC7): According to the control programs stored in the ROM (IC5), the CPU performs: • image scanner sequence control • communication with the copy processor control • pickup motor and delivery motor drives control GA (Gate Array) (IC4): According to commands from the CPU, the GA performs:
• scanning lamp drive control • sensors, switches, and LEDs control • solenoids control • fan motors control • flatbed document scanning motor control EEPROM (IC16): The EEPROM stores the specific backup adjustment data of the scanner, such as the leading-edge registration adjustment values and horizontal registration adjustment values. ROM (IC5): Stores the scanner control programs. Pickup motor driver IC (IC3): Drives the pickup motor based on commands from the CPU. Delivery motor driver (IC1): Drives the delivery motor based on commands from the CPU. Flatbed document scanning motor driver IC (IC 9): Drives the flatbed scanning motor based on commands from the GA.
Reset IC (IC17): Monitors +3.3V, and resets the CPU and GA when the power is turned on. Figure 47. Scanner controller circuit 80 Chapter 5 Theory of operation C8523-90921