Brother MFC-L8850CDW Service Manual

5-54
Confidential
1.3.28 Sensitivity adjustment of density sensor (Function code 72)
<Function>
This function is used to print the patch data for density sensor sensitivity adjustment on the
belt unit and measure the density with the density sensor. The characteristics of the density
sensor are calculated based on the value measured by the density sensor, and the parameter
for correcting developing bias voltage is adjusted.
<Operating procedure>
(1) Press the 7 and 2 keys in this order in the initial state of the maintenance mode. “PLS
WAIT 72” is displayed on the LCD and performs the sensitivity adjustment of the density
sensor.
(2) When this operation is completed without errors, the machine returns to the initial state of the
maintenance mode.
* # indicates the toner color (Y, M, or C) of which cartridge became empty.
Note:
If the sensitivity adjustment of the density sensor fails, “ERROR 72” is displayed on the
LCD. Display the error message by pressing the key, and take the following measure
that corresponds to the error message.
Error message Measure
dens_l_drk_err - Reconnect the harness of the eject sensor PCB.
- Replace the registration mark sensor unit.
- Replace the main PCB ASSY.
belt_err - Replace the belt unit.
- Replace the waste toner box.
- Replace the registration mark sensor unit.
- Replace the main PCB ASSY.
dens_pat_err
dens_calc_err
- Check if the toner cartridges are set in the correct order of colors.
- Replace the toner cartridges and drum unit.
- Replace the registration mark sensor unit.
- Replace the main PCB ASSY.
dens_led_adj_err - Replace the belt unit.
- Replace the waste toner box.
- Replace the registration mark sensor unit.
- Replace the main PCB ASSY.
lph_calc_err - Replace the toner cartridges and drum unit.
- Securely close the front cover.
- Wipe the scanner window of the laser unit with a soft lint-free
cloth.
- Re-assemble the laser unit.
TONER EMPTY #
*
Replace the empty toner cartridge and press the Mono Start key
to clear the error.
Perform the sensitivity adjustment of the density
sensor again.
Cover is Open Close the front cover.
Replace Toner
Replace the black toner cartridge and press the Mono Start key to
clear the error. Perform the sensitivity adjustment of the density
sensor again.

Brother MFC-L8850CDW Specifications

General

Type	all in one
Color	white
Tray Capacity	300
Automatic Document Feeder Capacity	50 sheets
Paper Size	8.5"x14"
Paper Handling	up to 300 sheets
Color Print Speed	32 pages per minute
Mono Print Speed	32 pages per minute
Print Resolution Color	up to 2400 x 600
Maximum Number of Pages Per Month	unknown
Scanner Type	flatbed
Scan Resolution	up to 2400 x 1200
Copier Resolution Mono	up to 600 x 600
Copier Resolution Color	up to 600 x 600
Cartridges	tn331bk, tn331c, tn331m, tn331y
Number Of Cartridges	4
Internal Memory	yes
Memory Card	no
Network	wired, wireless
Connectivity	usb, google cloud print
OS Compatibility	windows, mac os, linux
Mobile Devices Connection	yes

Weight and Dimensions

Height	19.3 inches
Width	20.7 inches
Net Weight	67.4 pounds