3 • Theory Of Operation
Sensor Summary (cont'd)
Carriage Return Sensor. This sensor is physically mounted on the purge
PCB that is housed in the purge unit located below the carriage. The sys-
tem uses this sensor to detect the position of the print carriage in the Y
direction. In this way, the carriage motor drive algorithm has the input nec-
essary to drive the carriage to the printing position and back to the home
position at the appropriate times in the machine cycle.
Pump Sensor. The system uses the output from this sensor to determine
the number of cycles/strokes completed for a defined maintenance/purge
operation. It is connected to the purge PCB which, in turn, is connected to
the main logic board through J120.
Cap Sensor. This sensor detects whether the print head is in the capped or
open position. It is connected to the purge PCB which, in turn, is connected
to the main logic board through J120.
Cover Sensor (DM400c/DM450c/DM475). This sensor detects the top
cover of the feeder as open or closed. It is connected to the feeder PCB
through J304 for DM400c/DM450c or through J315 on the feeder/WOW for
Feeder Input Sensor FS1 — Hopper (DM400c/DM450c/DM475). This
sensor detects the presence of envelopes in the hopper and is used by
the feeder CPU to start the mail flow process. This sensor is connected to
the feeder PCB through J302 for DM400c/DM450c or through J315 on the
feeder/WOW for the DM475.
Feeder Output Sensor FS2 (DM400c/DM450c/DM475). The system uses
this sensor to ensure that adjacent mail pieces are fed with the specified
pitch into the transport section of the mailing machine. This sensor also de-
tects jams in the paper path. It connects to the feeder PCB through J307 for
DM400c/DM450c or through J315 on the feeder/WOW for the DM475.
DM300c/DM400c/DM475 Service Manual (SV61801 Rev. D)