Gestetner B147 Service Manual page 465

OVERVIEW
Drum charge:
The charge roller gives the drum a negative charge
Laser exposure:
The laser beam from the laser diode (LD) goes through the lens and mirrors and
reaches the drum. The beam creates a latent image on the drum by turning the
laser beam on and off.
Development:
The development roller carries negatively charged toner to the latent image on the
drum surface. This machine uses four independent development units (one for
each color).
Image transfer:
The charge applied to the transfer roller attracts the toner from the drum to the
paper. Four toner images are super-imposed onto the paper.
Cleaning for OPC drum:
The cleaning brush and blade remove any toner remaining on the drum surface
after image transfer to the paper.
Quenching for OPC drum:
Quenching is done by illuminating the entire area of the drum surface with the laser
at the end of every job.
Paper attraction:
Paper is attracted to the transfer belt by the charge applied to the paper attraction
roller.
Separation:
Paper separates from the transfer belt when the belt curves away from it.
Cleaning and quenching for transfer belt:
The cleaning brush and blade clean the belt surface. The grounding roller inside
the transfer belt unit removes the remaining charge on the belt.
ID sensor:
The ID sensor board contains three ID sensors (one at the front, center, and rear).
The ID sensor detects the density of the ID sensor pattern on the transfer belt. The
ID sensor output is used for process control and for automatic line position, skew,
and color registration adjustments for the latent image.
SM 6-7 B147/B149/B190