Konica Minolta bizhub 500 Service Manual page 113

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21. IMAGE STABILIZATION CONTROL

B. Drum rotation

Prevent the drum charge leak such as an image flow at high humidity

When left in the low/normal humidity condition, prevent the uneven density due to the difference in sensitiv-

ity between the section facing the cleaner and the developing of the drum and other sections.

(2) Execution timing

It turns ON a specified period of time after the power switch (SW2) turns ON, and turns OFF when the dot diam-

eter adjustment is completed. However, when the 30 seconds extension of the early morning drum rotation is

selected in the software DipSW setting, it turns OFF 30 seconds after the completion of the dot diameter adjust-

• For bizhub 420, since the early morning dot diameter adjustment is not selected by default, no

drum rotation is made.

C. Dot diameter adjustment control

Stabilize the image over a long period of time by preventing the change of the laser 1 dot diameter due to the

write system being stained or the change of developability.

Create a dot pattern patch of a fixed density on the drum. The laser PWM at this time is maximum.

Read this dot pattern patch with the IDC sensor (IDCS) and calculate the difference between the sensor

output and the specified value.

Determine the correction amount of the laser power based on a value calculated to make corrections of the

laser power.

Repeat several times the control operations described above.

(3) Execution timing

When left for more than 8 hours, executed a specified period of time after the power switch (SW2) is turned ON.

However, this can be changed with the software DipSW setting.

• For bizhub 420, since the early morning dot diameter adjustment is not selected by default, no

execution is made.

D. Fusing preliminary rotation

Make uniform the surface temperature of the fusing roller and the fusing pressure roller.

(2) Execution timing

When the detected temperature of the thermistors /1 (TH1) and /2 (TH2) gets to the stipulated temperature.

• The stipulated temperature at which the fusing preliminary rotation is made varies for bizhub 500

Theory of Operation Ver1.0 Feb.2006

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