Fusing Roller Edge Cooling Control - Konica Minolta bizhub 500 Service Manual

18. FUSING SECTION
D. Low power mode and sleep mode
When each key is not pressed within a specified period of time after the completion of the last print, the system
changes into the low power mode or the sleep mode. The starting time for operation can be set individually for
the low power mode and the sleep mode. When the same starting time for operation is set for both modes, the
sleep mode takes precedence over the low power mode.
When the system changes into the low power mode, the ON/OFF of the fusing heater lamps /1 (L2) and /2 (L3)
is controlled so that the fusing roller gets to the prescribed temperature. The controlled temperature at this time
becomes lower than other controlled temperatures. And when the system changes into the sleep mode, the
power supply to L2 and L3 is shut off to put the system in the stand-by condition.
18.3.4

Fusing roller edge cooling control

A. Purpose
When printing continuously the sheets of paper the size of which is short in the main scan direction, the temper-
ature gets high at both edges of the fusing roller and the fusing pressure roller where no paper passages is
made. So, to prevent the temperature from getting high, the edges of each roller are cooled down by the fusing
cooling fans /Fr (FM2) and /Rr (FM8). This control operation is also conducted to avoid a fusing overshoot when
the main body makes an emergency stop due to the occurrence of a jam.
B. Fusing cooling fan control
The fusing cooling fans /Fr (FM2) and /Rr (FM8) vary depending on whether the size of paper in the main scan
direction is large or small. And their operations also vary when a jam occurs.
(1) Small size
Small size paper refers to the one the size of which is 200 mm or less in the main scan direction.
• ON timing
When the fusing exit sensor (PS3) detects the leading edge of paper exited and turns ON.
• OFF timing
When the fusing motor (M11) turns OFF.
(2) Large size
Large size paper refers to the one the size of which is 201 mm or more in the main scan direction.
• ON timing
When the detected temperature of the thermistor /2 (TH2) is over the prescribed temperature.
• OFF timing
When the detected temperature of TH2 goes down below the prescribed temperature.
(3) When a jam occurs.
• ON timing
A jam is detected inside the main body.
• OFF timing
A specified period of time after the fusing cooling fans /Fr (FM2) and /Rr (FM8) turn ON.
Note
• When the power switch (SW2) turns OFF due to the occurrence of a jam, or when the interlock
switch (MS) is turned OFF by opening ADU, the power supply to each fan is shut off and, even if it
is within a specified period of time, the fan turns OFF. However, when SW2 and MS are turned ON
within a specified period of time, FM2 and FM8 turn ON again.
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Theory of Operation Ver1.0 Feb.2006