Panasonic DP-CL18 Technical Manual page 26

DP-CL18
3.5.5. Accumulator Drive Circuit
This circuit consists of 2 solenoid drive circuits (accumulator cam switching solenoid, Mono/Color Changer solenoid), accumulator
belt position detection (circuit consist of the accumulator cam home position sensor) and solenoid drive short detection circuit. The
accumulator cam switching solenoid, Mono/Color changer solenoid and accumulator cam home position sensor are located on the
accumulator tension unit. The accumulator cam switching solenoid is used for controlling STR bias roller position, FTR bias roller
position and accumulator belt tension. The Mono/Color changer solenoid is used for selecting the FTR bias rollers. At the
monochrome printing mode, the signal MONOSOL (pin 169 of IC14) is a low and the Mono/Color changer solenoid is not active.
At the color printing mode, the signal MONOSOL becomes a high, turning on the Mono/Color changer solenoid. As a result, the
FTR rollers for black, cyan, magenta and yellow are activated by the mechanism (linked the Mono/Color changer solenoid
operation) in the accumulator tension unit. The short detection circuit is for detecting whether the solenoid drive circuit is shorted
or not. If this circuit is shorted, the signal NFAILDR (pin173 of IC14) becomes a low level. IC14 receives this signal, and detects
that the solenoid drive circuits for the accumulator cam switching and mono/color changer solenoids are shorted. The error
message "Printer Error 47" is displayed on the LCD display.
There are 4 status positions for the accumulator tension unit for controlling the printing process.
· Home Position
· Accumulator Belt Cleaning Position :
The cleaning of the accumulator belt is done.
· Toner Transferring Position :
The FTR bias roller(s) is (are) contacted with the accumulator belt for transferring the toner to the accumulator belt.
· FTR Roller Release Position :
The FTR bias roller(s) is (are) released from the accumulator belt.
The following Figure-1 indicates the home position status of the accumulator tension unit. When the accumulator tension unit is at
the home position, the hook of cam ratchet is engaged with the Detent (A). The accumulator cam home position sensor tab
intersects into the accumulator cam home position sensor as shown in the Figure-1.
Shifting from Home Position to Accumulator Belt Cleaning Position :
When the printing process is started, the signal ITSOL (pin 168 of IC14) becomes a high for the proper time set by the software
programing, turning on the accumulator cam switching solenoid. As a result, the accumulator cam switching solenoid is energized,
releasing the hook of cam ratchet from the Detent (A) on the cam ratchet. After this, the cam ratchet wheel rotates in the arrow (1)
by the rotation from the BK motor. After the proper time, the signal ITSOL is changed from the high to the low, turning of the
accumulator cam switching solenoid. And, the hook of cam ratchet engages with the Detent (B). When the hook of cam ratchet
engages with the Detent (B), the rotation of cam ratchet wheel is stopped by the mechanical clutch device in the accumulator
tension unit. The accumulator Belt Cleaning Position status indicates this status. While shifting from the home position to
accumulator belt cleaning position, the accumulator belt is taken up the slack in the accumulator belt by the mechanism (linked the
cam ratchet wheel operation) in the accumulator tension unit. Besides, the sensor tab also rotates in the arrow (2) direction and the
signal ITHOME1 (pin 183 of IC14) changes from the high to the low. If the signal ITHOME1 does not change within the time set
by software programing, the error message "Printer Error 24" is displayed on the LCD display. At the accumulator belt cleaning
position, the sensor tab is located as shown in the Figure-2.
Shifting from Accumulator Belt Cleaning Position to Toner Transferring Position :
After cleaning the accumulator belt at the accumulator belt cleaning position, the signal ITSOL (pin 168 of IC14) becomes a high
for the proper time set by the software programing, turning on the accumulator cam switching solenoid. After this, the accumulator
tension unit shifts to the Toner Transferring Position in the same manner as the above "Shifting from Home Position to accumulator
Belt Cleaning Position". While shifting to "Toner Transferring Position", the first transfer roller (FTR) and second transfer roller
(STR) are contacted with the accumulator belt by the mechanism (linked the cam ratchet wheel operation) in the accumulator
tension unit. At the Toner Transferring Position, the sensor tab is located as shown in the Figure-2. If the signal ITHOME1 does not
change within the proper time while this shifting, the error message "Printer Error 24" is displayed on the LCD display.
After transferring the toner for the last page to the accumulator belt, the signal ITSOL changes the high to the low and the status
of the accumulator tension unit is shifted to "FTR Roller Release Position".
Shifting from Toner Transferring Position to FTR Roller Release Position :
The status of accumulator tension unit is shifted to the FTR Roller Release Position in the same manner as the above "Shifting from
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