Xerox Phaser 7400 Service Manual

Theory of Operation 2-13
Automatic Density Control
The printer uses a series of test patches printed down the center of the Transfer Unit
belt to monitor the density of toner being supplied to the Imaging Unit drums. The
test patches consist of a grouping of all four colors applied repeatedly to the Transfer
Unit belt at density levels of 15, 30 50, 70, 85, and 100%. During the adjustment
cycle, these patches are printed twice and the ADC Sensor voltage outputs are stored
as reference values. During the status cycle, the test patches are generated once and
the resulting ADC Sensor voltages are compared to the reference values obtained
during the adjust cycle. Differences in the adjust and status ADC Sensor values
indicate how much to adjust the amount of toner being dispensed for each color.
The following diagram depicts the Transfer Unit belt with the test patches.
Selective Control: Paper Pick
Unless changed in printer setup, the default tray is Tray 2. Trays in the optional
1650-Sheet Feeder are identified as Trays 3, 4, and 5. The tray in the optional
550-Sheet Feeder is identified as Tray 3. If both optional feeders are installed, the
550-Sheet Feeder tray is identified as Tray 3, and the trays of the 1650-Sheet Feeder
are identified as Trays 4, 5, and 6.
Note
The Phaser 7400 printer supports a maximum of 4 optional trays.
Duty 100%
Duty 70%
Duty 30%
Transfer
Unit
x2 Times
ADC Sensor
Duty 100%
Duty 85%
Duty 70%
Duty 50%
Duty 15%
Duty 30%
Transfer
Unit
ADC Sensor
s7400-624

Xerox Phaser 7400 Specifications

General

Color	Yes
Print technology	Laser
Maximum resolution	600 x 1200 DPI
Time to first page (black, normal)	12 s
Print speed (black, normal quality, A4/US Letter)	40 ppm
Print speed (color, normal quality, A4/US Letter)	36 ppm
Storage media	HDD
Internal memory	512 MB
Processor model	PowerPC
Maximum internal memory	1 MB
Internal storage capacity	20 GB
Total input capacity	800 sheets
Maximum input capacity	3000 sheets
Paper tray 2 input capacity	350 sheets
Auto document feeder (ADF) input capacity	1650 sheets
Maximum print size	297 x 420 mm
Paper tray media types	Envelopes, Labels, Transparencies
Non-ISO print media sizes	Executive (184 x 267mm), Folio (media size), Letter (media size), Statement (140 x 216mm), Legal (media size)
Maximum ISO A-series paper size	A3
Power requirements	100-240V, 50/60Hz
Networking features	Fast Ethernet
Supported media weight(s)	270 g/m²
Maximum operating temperature range (T-T)	10 - 32 °C
Certification	FCC p.15 A, CE
Storage temperature (T-T)	-20 - 60 °C
Operating temperature (T-T)	-4 - 140 °F
Storage relative humidity (H-H)	10 - 95 %
Operating relative humidity (H-H)	20 - 80 %
Maximum duty cycle	150000 pages per month

Weight and Dimensions

Dimensions (WxDxH)	1438 x 623 x 975 mm