HP Enterprise 500 manual Image stabilization control, 13Image-stabilization controls

If data from the color-misregistration and image-density sensors is outside a specified range when the product is turned on or when it is beginning the calibration sequence, the DC controller determines that these sensors have failed, and it notifies the formatter.

Image stabilization control

Environmental changes or deterioration of the photosensitive drums and toner can cause variations in the image density. The image-stabilization control reduces these fluctuations. There are three kinds of image stabilization controls.

Table 1-13Image-stabilization controls

Image stabilization control	Description
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, controls, and related
	biases. This control occurs under the following circumstances:
	●	The print cartridge is replaced.
	The DC controller notifies the formatter when it encounters a communication error
	with the environmental sensor.
Image density control (DMAX)	This control corrects variations in image density related to deterioration of the
	photosensitive drum or the toner. The DC controller adjusts the high-voltage biases
	to correct the problem under the following conditions:
	●	The sub thermistor detects a temperature that is too low when the product is
		turned on.
	●	After a specific period of the completion of a print operation
	●	A print cartridge is replaced.
	●	The ITB is replaced.
	●	A specified number of pages have printed.
	●	The formatter sends a command.
	●	The environment is relatively charged.
Image halftone control (DHALF)	The DC controller measures the halftone pattern according to the command from the
	formatter. The formatter performs this control to calibrate the halftone, based on the
	halftone-density measurements, under the following conditions:
	●	The formatter sends a command.
	●	DMAX is completed.

The DC controller determines a RD sensor failure and notifies the formatter if it detects an out-of- specified-data value from the RD sensor when the product is turned on or when the color misregistration control starts.

ENWW Image formation system 37