HP Color LaserJet Professional CP5220 Service Manual - Page 53

Environment change control, Image stabilization control,

Page 53 highlights

The DC controller forms pattern of toner on the surface of the ITB and measures a misaligned length with the RD sensor and the RDL sensor. Accordingly, the formatter calibrates the color-misregistration. Figure 1-29 Color-misregistration control RD sensor ITB RDLsensor Pattern of toner The DC controller commands the formatter to perform the color-misregistration control whenever one of the following occurs: ● The product is turned on or the door is closed, after replacing any one of the cartridges ● The product is turned on or the door is closed, after replacing the ITB unit or the laser scanner unit ● A specified number of pages have been printed ● Continuous printing for a specified period of time ● Cold starting of the fuser when the product is turned on If data from the RD or RDL sensor is out of a specified range during the cartridge-presence detection or when starting the color-misregistration control, the DC controller determines an abnormal sensor and notifies the formatter. Environment change control The environment change control calibrates each high-voltage bias to obtain an appropriate image according to the environment changes. The DC controller determines the environment, where the product is installed, based on the surrounding temperature and humidity data from the environment sensor. It adjusts the high-voltage biases to accommodate environmental changes. The DC controller determines an environment sensor abnormality and notifies the formatter when it detects out of specified range data from the environment sensor. Image stabilization control The image stabilization control reduces the fluctuations in image density caused by environmental changes or deterioration of the photosensitive drums or toner. The two kinds of image stabilization controls are image density control (DMAX) and image halftone control (DHALF). ENWW Image-formation system 41

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The DC controller forms pattern of toner on the surface of the ITB and measures a misaligned length
with the RD sensor and the RDL sensor. Accordingly, the formatter calibrates the color-misregistration.
Figure 1-29
Color-misregistration control
ITB
Pattern of toner
RDL
sensor
RD sensor
The DC controller commands the formatter to perform the color-misregistration control whenever one
of the following occurs:
The product is turned on or the door is closed, after replacing any one of the cartridges
The product is turned on or the door is closed, after replacing the ITB unit or the laser scanner unit
A specified number of pages have been printed
Continuous printing for a specified period of time
Cold starting of the fuser when the product is turned on
If data from the RD or RDL sensor is out of a specified range during the cartridge-presence detection
or when starting the color-misregistration control, the DC controller determines an abnormal sensor and
notifies the formatter.
Environment change control
The environment change control calibrates each high-voltage bias to obtain an appropriate image
according to the environment changes. The DC controller determines the environment, where the
product is installed, based on the surrounding temperature and humidity data from the environment
sensor. It adjusts the high-voltage biases to accommodate environmental changes.
The DC controller determines an environment sensor abnormality and notifies the formatter when it
detects out of specified range data from the environment sensor.
Image stabilization control
The image stabilization control reduces the fluctuations in image density caused by environmental
changes or deterioration of the photosensitive drums or toner. The two kinds of image stabilization
controls are image density control (DMAX) and image halftone control (DHALF).
ENWW
Image-formation system
41