The coefficient of friction on the surface of the photosensitive drum where the edge of the cleaning blade remains in contact tends to change, causing uneven rotation
and thus blurring.
This problem tends to occur during the initial period of use (less than 10K), when the coefficient of friction is relatively even, or when a halftone image is generated
after leaving the machine alone for 1 to 2 days. This problem, on the other hand, tends to disappear when about 10 printouts are made.
This problem can also occur when the drum unit is taken out of and put back in the machine, with the edge of the cleaning blade forcing itself against the surface
of the photopositive drum and increasing the friction.
The presence of foreign matter inside the developing assembly can make its way to the developing cylinder, preventing toner from being evenly deposited on the