3 charging potential control – Konica Minolta CF5001 User Manual

Page 120

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CF5001 Ver.1.0 Sep. 2003

IMAGE STABILIZATION CONTROL

2-67

II UNIT EXPLANA

TION

14.3 Charging potential control

14.3.1

Correction of the reference value

The purpose of this control is to set the charging potential for each color to the reference level.

The charging potential control is carried out by the drum potential sensors /Y, /M, /C and /K (DRPS Y, M, C

and K), drum potential sensor boards /Y, /M, /C and /K (DRPSB Y, M, C and K), drum motors /Y, /M, /C and

/K (M14, M15, M16 and M17), and the developing motors /Y, /M, /C and /K (M20, M21, M22 and M23), and

controlled by the printer control board (PRCB). Related sensors include the temperature/humidity sensor

(TEMP/HUM).

A.

Explanation of the operation

Based on the DC bias value determined by the Dmax control, the grid voltage is corrected by using an out-

put value read from the drum potential sensor so that the value becomes a charging potential shifted by

the specified value from this DC bias value.

B.

Timing of the operation

When the main switch (SW2) is turned on for the first time in 6 hours or more after it was turned off.

When the job starts 6 hours or more after the SW2 has been turned on.

Every 1,000 pages of output. However at the time of completion of the job, when the 1,000th page is

contained in the job.

When the humidity has changed more than 30% RH from the value measured at the last operation.

When the job starts where the process speed is slowed down to 1/2 or 1/3 speed. However, once

operated under this condition after the SW2 turns on, the operation is not carried out again until the

SW2 turns off.

14.3.2

Low humidity environment correction

When in a low humidity environment, the humidity is lower in the enclosed area (near the cleaning section)

along the drum circumference. This result in an uneven charging potential along the circumference of the

drum. Accordingly, this correction method is used to prevent these conditions from happening.

A.

Explanation of the operation

To ease the influence on the drum caused by the ambient humidity around the drum, the drum for each

color is rotated 45° periodically while in idling.

B.

Timing of the operation

The drums are turned once every 3 minutes when the humidity gets below 30% RH.

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