Ricoh G148, Service Manual

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If the toner collection coil sensor [F] (not shown) does not change within 3 seconds after the drum motor
turns on, the transport coil is clogged and cannot rotate, then SC495 (Toner Recycling Unit Error) is logged.
When the toner overflow switch (not shown) detects that the toner collection bottle [G] is full, operation
halts after an additional 100 copies and the machine prompts the user to replace the toner collection bottle.
The toner collection bottle set switch [H] detects when a new toner collection bottle is installed. If installing
a new bottle does not reset the machine, SC496 (Toner Collection Bottle Error) is logged.
Process Control
Drum potential gradually changes toward the end of the service lives for key electrical components such
as the charge corona unit or drum surface.
What Happens at Power On
Here is a description of what happens while the fusing temperature is below 100ºC immediately after the
power switch is switched on (process control must also be enabled with SP3901, or this will not happen).
At any time, this process can also be executed manually by using SP2962. However, process control must
be enabled with SP3901 and the fusing temperature must be below 100ºC, or this will not work.
1. Potential sensor is calibrated.
2. Drum starts first rotation after fusing temperature reaches 140ºC.
3. Readout from the potential sensor is used to adjust:
• Development bias (Vb)
• Grid voltage (Vg)
• Laser diode (LD) power.
• This step occurs only if process control is enabled with SP3901 (Auto Process Control On/
Off Setting). If this SP is disabled, then:
• Development bias is set to the value stored in SP 2201 001
• Grid voltage is set to the value stored in SP 2001 001
• Laser power is set to a fixed value
4. ID sensor is calibrated (Vsg).
5. TD sensor is calibrated (Vref).
These calibrations are used to determine toner supply, so it is very important that the developer be initialized
with SP2963 (Installation Mode) at installation and with SP2801 (TD Sensor Initialization) when the de-
veloper is replaced.
Drum Unit
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