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1155SBM1806A
18-6. CPM Control
The CPM (copies/minute) control is provided to keep good fusing performance even
in multi-copy cycles and with the system power sourced from a single power outlet.
<What is CPM Control?>
As noted earlier, only Upper Fusing Roller Heater Lamp is ON during a copy
cycle. Because of that, the Fusing Roller surface temperature goes down in a
multi-copy cycle, resulting in degraded fusing performance. The copier therefore
estimates the fusing performance based on the Fusing Roller surface tempera-
ture and, when the fusing performance is considered to be degraded, it
decreases the CPM by 25% in an attempt to recover good fusing performance.
(When the CPM is decreased, it provides a greater interval between sheets of
paper, which gives time for the Fusing Roller surface temperature to increase.
This recovers the fusing performance. When good fusing performance is recov-
ered, the copier resumes the normal CPM.)
<CPM Control>
When the normal CPM is 62 copies/min., for example, and when the copier
determines that fusing performance has been degraded, it reduces the CPM by
25% to 45 copies/min.
During the CPM control, the copier provides a greater interval between scan
motions and between sheets of paper, thereby giving the Fusing Roller time to
restore the temperature. (The system speed is not varied.)
The CPM control can be activated if a multi-copy cycle is run immediately after
the power has been turned ON in the morning (when the Fusing Rollers remain
cool). In times other than early morning, however, the Lower Fusing Roller is
heated by Lower Fusing Roller Heater Lamp from the inside and, even with a
multi-copy cycle, the CPM control is not readily activated. (For paper with a large
weight and size, however, the CPM control can be activated even at times other
than early morning.)
M-120
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