Konica Minolta bizhub C658 Service Manual page 1892

bizhub C658/C558/C458/C368/C308/C258
1. Fixed control: The electric energy of the IH coil is controlled with a predetermined value; the control is performed for temperature
control during warm-up.
2. PID control: The electric energy of the IH coil is controlled through a combination of the P control, I control, and D control; Used for
temperature control in the normal standby state, during a print cycle, and in the low power mode.
3. P control: The electric energy of the IH coil is controlled according to the difference between a target temperature and a detected
temperature; used for temperature control in the printing, standby, low power, pre-standby state, and before printing.
4. I control: Temperature errors arising from individual variability in the IH coil and fusing unit are corrected; not to be performed
individually.
5. D control: The electric energy of the IH coil is corrected to respond to sudden changes in temperature; not to be performed individually.
(3) Fusing temperature control during warm-up
• To prevent image fixability from being degraded due to environmental changes when the main power switch is turned ON, three different
warm-up modes are incorporated for fusing temperature control.
• The warm-up mode is performed "at low temperatures", "at ordinary temperatures", or "under high humidity condition".
• In the warm-up mode under high humidity condition, the warm-up time is extended to prevent paper from curling and the difference in
temperature between the fusing belt and fusing pressure roller is minimized.
• When the temperature of the fusing belt reaches the warm-up completion temperature, control is passed onto the pre-standby process.
• Printing then starts if there is a print request. The system transitions to the pre-standby temperature control if there is no print request.
• If the fusing pressure roller is pressed, the fusing pressure motor turns on to release the fusing pressure roller.
Warm up mode
Warm-up at low temperatures
Warm-up at ordinary temperatures
Warm-up under high humidity condition
• *1: Absolute humidity: water content contained in the air (1 m 3 ) as steam regardless of the temperature
[1]
[5]
[1] Machine interior paper temperature 18°C or less
[3] Absolute humidity, specified value or more
[5] Warm-up at low temperatures
[7] Warm-up at ordinary temperatures
(4) Temperature control during stand-by
• If no print request is received after the temperature control in the pre-standby state is started, control is passed onto the standby process.
• When a predetermined amount of time elapses after the pre-standby control starts, temperature control is performed through standby
control.
• Within a specified time after standby temperature control starts, the target temperature is maintained for each mode in low-temperature,
normal, and high-humid state.
• The standby temperature control ensures that the temperature of fusing belt in the standby state is not decreased.
* Counted period for standby control includes the printing time.
(5) Temperature control during the print cycle
• Temperature control is provided in order to keep optimum fusing performance with various factors, such as the type of paper, print mode,
paper temperature*1, use of paper of small size, decreased temperature during paper passage, and warm-up carried out with a cool
fusing unit.
• *1: The paper temperature is used as data to control the fusing temperature. The paper temperature sensor that is installed in the
paper feed section measures this temperature as the "Internal paper feed section temperature".
(6) Temperature control under low power mode
• The temperature of the fusing belt is decreased to thereby reduce power consumption during the low power mode.
Paper temperature
18 °C or less
More than 18 °C
More than 18 °C
[2]
[4]
[3]
[7]
[6]
O THEORY OF OPERATION bizhub C658/C558/C458/C368/C308/C258 > 14.
Environment
[2] Machine interior paper temperature exceeding 18°C
[4] Absolute humidity, less than the specified value
[6] Warm-up under high humidity condition
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O-117
FUSING SECTION (bizhub C658/C558)
Machine interior humidity (absolute humidity
*1)
Not judged by absolute humidity
Less than a predetermined value
Predetermined value or more