Ricoh SP 8400DN Field Service Manual page 1404

Ricoh a3 size black and white laser printer.

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7.Detailed Descriptions

To easily remove paper in the event of a jam in the fusing unit, a pressure release mechanism is provided.

The pressing or releasing movement is applied together when the right cover [A] opens/closes: When the right

cover is closed, pressure is applied. When the right cover is open, the pressure is released.

Fusing Temperature Control

Warm-up mode

After power ON, fusing warm-up begins. The fusing motor or fusing/paper exit motor is switched ON, the

halogen heater is energized, and the fusing temperature is increased to the "reload target temperature."

When the fusing warm-up is completed, the fusing motor or fusing/paper exit motor is switched ON for a

certain time, and the fusing temperature is maintained at the "reload target temperature."

Standby mode

After fusing reload, when a certain time has elapsed, power supply to the halogen heater is switched OFF,

and the fusing motor or fusing/paper exit motor is switched OFF. At the same time, the temperature is

maintained at the "standby target temperature (SP1107-001)" by the halogen heater.

In standby mode, the fusing motor or fusing/paper exit motor is switched ON intermittently.

Printing ready mode

After returning to standby mode, the halogen heater is re-energized, and the fusing temperature is raised to

the "printing ready target temperature." If printing is not required, the machine again enters the standby mode

after a certain time has elapsed.

If printing is required during return to standby, the halogen heater is energized, the fusing temperature is

increased to "target temperature after reload/after paper feed," and the print job starts.

CPM Down Control

To maintain image quality and printer quality, this printer has a low-temperature CPM mode and high-temperature

CPM mode, and implements 3 levels of CPM down according to the usage situation and printer state.

Low-temperature CPM mode

In a low-temperature environment, the fusing lamp cannot keep up, and it may be difficult to maintain the

target temperature. To handle this, the detection temperature of the fusing center thermopile is checked at

given intervals, and if the detected temperature is below a threshold value, the CPM is decreased by 1 level.

This low temperature CPM reduction is performed in the following 3 levels:

CPM down level

Hot CPM mode

To shorten warm-up time and reduce the TEC value, this printer employs a fusing unit with a low heat

For this reason, the temperature of those parts of the fusing belt where paper does not pass easily increases,

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