Engine F/W Contol Algorithm - Dell 1135N Service Manual

2.2.5 Engine F/W Control Algorithm
2.2.5.1 Feeding
If feeding from a cassette, the drive to the pickup roller is controlled by a solenoid. The on/off time the
solenoid is controlled by Main PBA. The Paper Jam protocols are as follows:
Item
- After picking up, paper cannot be entered due to paper is not fed.
- After picking up, paper does not reach the Feed Sensor in after a predetermined time due
to paper slippage, etc.
- After picking up, if the Feed Sensor does not detect paper after a predetermined time
JAM 0
following the initialization of another take-up retry.
* 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.
- The trailing edge of the paper must clear the Feed Sensor after predetermined time.
(The feed sensor cannot be OFF)
JAM 1 - The leading edge of the paper must detect the Exit Sensor within a predetermined after
leaving the Feed Sensor. (The exit sensor cannot be ON)
* The paper exists between the feed sensor and the exit sensor.
JAM 2 - The trailing edge of the paper must clear the Exit Sensor after predetermined time.
2.2.5.2 Transfer
The charging, developing and the transfer voltages are controlled by PWM (Pulse Width Modulation). Each
output voltage may change 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 through AD converter. The voltage value for impressing to the transfer
roller is decided by this value change.
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