HP Color LaserJet Enterprise CP5525 Service Manual - Page 67

Environment change control, Image stabilization control, Image density control (DMAX)

Page 67 highlights

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). Image density control (DMAX) The image density control calibrates each high-voltage bias to stabilize the image density variation caused by the deterioration of the photosensitive drum or toner. The DC controller commands the formatter to control the image density under the following conditions: ● The detected temperature of the fuser is a specified degree or lower when the product is turned on ● The product is turned on, or the door is closed, and also whenever a specified number of pages have been printed 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 ● After a specified period of time from the previous image density control ● The environment is changed for a specified condition after the previous image density control Image halftone control (DHALF) The image halftone control is performed by the formatter to calibrate the halftone. The DC controller measures the halftone pattern according to a command from the formatter. Accordingly, the formatter calibrates the halftone. The DC controller controls the image halftone under the following conditions: ● The image density control is completed ● The formatter sends a command ENWW Image-formation system 43

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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).
Image density control (DMAX)
The image density control calibrates each high-voltage bias to stabilize the image density variation
caused by the deterioration of the photosensitive drum or toner. The DC controller commands the
formatter to control the image density under the following conditions:
The detected temperature of the fuser is a specified degree or lower when the product is turned on
The product is turned on, or the door is closed, and also whenever a specified number of pages
have been printed 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
After a specified period of time from the previous image density control
The environment is changed for a specified condition after the previous image density control
Image halftone control (DHALF)
The image halftone control is performed by the formatter to calibrate the halftone. The DC controller
measures the halftone pattern according to a command from the formatter. Accordingly, the formatter
calibrates the halftone. The DC controller controls the image halftone under the following conditions:
The image density control is completed
The formatter sends a command
ENWW
Image-formation system
43