Service manual

Chapter 2
2-12
The machine uses an on-demand method, which requires a low thermal capacity. The method enables the machine to start up quickly and its heater to use little
power while the machine is in a standby state. The machine may therefore be characterized by a short wait time and low energy consumption.
The machine applies a positive DC bias to its pressure roller for the purpose of reinforcing the retention of toner on print paper, consequently preventing stray toner.
Moreover, to prevent offset from the fixing film, the film surface is given a fluorine coating. The sleeve of the fixing film is made of rubber.
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2.3.1.7 ITB Cleaning Block
0007-4982
The ITB and drum are cleaned in this block by returning residual toner on the ITB into the waste toner case through the drum, as a preparation for the next print
operation.
This block comprises the following four steps:
Residual toner
In the secondary transfer step, not all the toner on the ITB is transferred onto paper. Some toner remains on the ITB. This toner is called the residual toner.
Step 9: Auxiliary ITB cleaning roller charging
In this step, the holding force of the residual toner on the ITB is strengthened to prevent the toner from falling from the ITB and scattering in the printer.
A DC positive bias is applied to the auxiliary ITB cleaning roller to charge the residual toner on the ITB positively. Then the residual toner is pressed to the ITB.
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Step 10: ITB cleaning roller charging
The residual toner on the ITB is charged uniformly positively in this step.
A DC positive bias and AC bias are applied to the ITB cleaning roller in order to apply positive charges to the residual toner. This will make the next step, ITB
cleaning, easier.
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Step 11: ITB cleaning
The positively charged residual toner on the ITB is returned to the drum in this step. A potential difference is produced between the drum and the ITB by applying
Fixing film
Fixing heater
Paper
Toner
Pressure roller
DC bias
Charged
residual toner
ITB
DC bias
Residual toner
Auxiliary ITB
cleaning roller
ITB
ITB cleaning roller
DC bias
Charged
residual toner
Residual toner
AC bias