Konica Minolta magicolor 2490MF Service Manual page 40

Theory of operation ver. 1.0 July. 2006
CCD (Photoelectric
[1]
conversion)
Image processing
[2]
board
[3] Laser exposure
[4] Photo conductor
Photo conductor
[5]
charging
[6] Developing
[7] 1st image transfer
[8] 2nd image transfer
[9] Paper separation
Photo conductor
[10]
cleaning
[11] Transfer belt cleaning
[12] Fusing
• Light reflected off the surface of the original is converted to a corre-
sponding electric signal by CCD and the resultant electric signal is sent
to the image processing board.
• The intensity of the laser light is controlled based on the image signal
transmitted to this board.
• The surface of the photo conductor is irradiated with the laser light and
an electrostatic latent image is thereby formed.
• The image projected onto the surface of the photo conductor is con-
verted to a corresponding electrostatic latent image.
• A negative DC charge layer is formed on the surface of the photo con-
ductor.
• The toner, negatively charged in the hopper, is attracted onto the elec-
trostatic latent image formed on the surface of the photo conductor. It is
thereby changed to a visible, developed image.
• A DC negative bias voltage is applied to the developing roller, thereby
preventing toner from sticking to the background image portion.
• A DC positive voltage is applied to the backside of the transfer belt,
thereby allowing the visible, developed image on the surface of the
photo conductor to be transferred onto the transfer belt.
• A DC positive voltage is applied to the backside of the paper, thereby
allowing the visible, developed image on the surface of the transfer belt
to be transferred onto the paper.
• The paper, which has undergone the 2nd image transfer process, is
neutralized.
• The residual toner left on the surface of the photo conductor is scraped
off.
• A charge is applied to the transfer belt. By potential difference, residual
toner on the surface of the transfer belt is collected for cleaning.
• Toner is permanently fused to the paper by the combination of heat and
pressure applied by the fusing roller.
5. Image creation process
9