Solution

When using clear toner, the mottled effect can be improved by applying another layer of clear toner to the mottled area. However, a larger M/A (mass per unit area) of clear toner results in more glossiness, and then causes color tone changing.

Adjustments of Paper Transfer Current may cause the following side effects.
Decreasing the paper transfer current (ex: -82ua -92uA): White spots is getting worse in the low temperature and low humidity condition or Bk image in the full color mode is getting lighter in the high temperature and high humidity condition.
Increasing the paper transfer current (ex: -82ua -72uA): Mottled effect is getting worse in the low temperature and low humidity condition.

Adjustments of Image Transfer Current may cause the following side effects.
Decreasing the image transfer current (ex: 40uA 45uA): Residual image is getting worse.
Increasing the image transfer current (ex: 40uA 35uA): Bk image in the full color mode is getting lighter in the high temperature and high humidity condition.

AC transfer adjustment may cause toner scattering worse for a halftone or text image. The line speed of the machine is also reduced by this adjustment. As a result of this, the productivity of the machine is lowered.

After taking the above measures, do the color calibration adjustment of the external controller.

The applicable numbers for the items in the “Custom Paper Settings” vary depending on the printing mode of the machine. Refer to Applied Setting Items for Custom Paper Setting about which number you need to adjust.