Development Block - Canon CP660 Service Manual

C.

Development Block

In this block, toner is deposited on the latent static image on the surface of the pho-
tosensitive drum, thereby turning it into a visible image. The machine's black toner is a
magnetic, single-component toner, and its color toner is non-magnetic, single-component
toner; the printer unit uses the toner projection method of development.
Step 4 (development)
As previously mentioned, the machine's black toner is a magnetic, signal-component
toner consisting of magnetite and resin. Its color toner, on other hand, is a non-magnet-
ic single-component toner composed of resin. These toners have insulating characteris-
tics, and are negatively charged by friction against the surface of a rotating cylinder and
the surface of a blade.
The color toner may be yellow, magenta, or cyan, and is in a specific toner cartridge.
The color toner cartridge is housed in a developing rotary, and the rotation of the rotary
positions each cartridge against the photosensitive drum.
The black toner cartridge is mounted outside the developing rotary, and is positioned
against the photosensitive drum at all times.
When an area of the photosensitive drum exposed to a laser beam approaches a
toner layer (charged to negative potential), the difference in potential between the surface
of the drum and the developing cylinder (higher on the drum side) causes the toner to
jump and adhere the surface of the drum. This is called "jumping development," and turns
the latent static image on the surface of the photosensitive drum into a visible image.
The developing cylinder is given an AC bias to facilitate movement of toner to the sur-
face of the photosensitive drum and to improve contact on output images. The DC bias
applied to the developing cylinder is varied in reference to the result of image density cor-
rection control (p. 4-21) executed on the DC controller PCB.
COPYRIGHT © 1999 CANON INC.
Download free service manual at http://printer1.blogspot.com
CANON 660/2100 REV.0 FEB. 1999 PRINTED IN JAPAN (IMPRIME AU JAPON)
CHAPTER 1 GENERAL DESCRIPTION
1-25