Samsung ML-4551NR - Engine F;W

Service Manual
Summary of Product
3-20
Samsung Electronics
3.3.3 Engine F/W
3.3.3.1.Control Algorithm
• Feeding
If feeding from a cassette, the drive of the pickup roller is controlled by controlling the solenoid. The on/off of the
solenoid is controlled by controlling the general output port or the external output port. If feeding from a manual
feeder, decide to insert the paper according to the operation of the manual sensor, and by driving the main motor,
insert the paper in front of the feed sensor. While paper moves, occurrence of Jam is judged as below.
3.3.3.1.2 Driver
By gearing, the main motor drives the rollers such as feeding roller, developing roller, fuser roller, and exiting roller.
The step motor is controlled for the such acceleration section and steady section. In the initial stage of the motor
run, appoint the acceleration section to prevent the step-out of the motor. It is controlled by the A 3977 motor dri-
ver IC. The step signal and the enable signal are sent to make the phase for driving the motor in CPU.
3.3.3.1.3 Transfer
The charging voltage, developing voltage and the transfer voltage are controlled by PWM (Pulse Width
Modulation). The each output voltage is changeable due to the PWM duty. The transfer voltage admitted when
the paper passes the transfer roller is decided by environment recognition. The resistance value of the transfer
roller is changed due to the surrounding environment or the environment of the set, and the voltage value, which
changes due to the environments, is changed through AD converter. The voltage value for impressing to the trans-
fer roller is decided by the changed value. Each voltage value is controlled according to 3.3.4.2 Timing Chart.
ITEM Description
JAM 0
JAM 1
JAM 2
DUPLEX
JAM 1
DUPLEX
JAM 0
- After picking up, paper cannot be entered due to paper is not fed.
-
After picking up, paper entered but it cannot reach to the feed sensor in certain time due to slip, etc.
- After picking up, if the feed sensor is not on, re-pick up. After re-picking up, if the feed sensor is
not on after certain time, it is JAM 0.
* It is a status that the leading edge of the paper doesn’t pass the feed sensor.
- Even though the paper reaches to the feed sensor, the feed sensor doesn’t be ON.
* It is a status that the leading edge of the paper already passes the feed sensor.
- After the leading edge of the paper passes the feed sensor, the trailing edge of the paper cannot
pass the feed sensor after a certain time. (The feed sensor cannot be OFF)
- After the leading edge of the paper passes the feed sensor, the paper cannot reach the exit sen-
sor after certain time. (The exit sensor cannot be ON)
* The paper exists between the feed sensor and the exit sensor.
- After the trailing edge of the paper passes the feed sensor, the paper cannot pass the exit sensor
after certain time.
- After the trailing edge of the paper passes the exit sensor, the leading edge of the paper cannot
reach the duplex sensor after certain time.
- After the leading edge of the paper passes the duplex sensor, the leading edge of the paper can-
not reach the feed sensor after certain time.