EPSON Stylus Pro 4400/4450/4800/4880/4880C Revision C
Operating Principles Printer Mechanism Components 123
 ASF/Pump Motor (Stepping motor)
When the transmission path is switched to the Pump Unit side by Carriage 
Unit movement and the DE Lock Lever, the ASF/Pump Motor can drive the 
ink maintenance system such as pump and wiper, etc.
Movements of the ASF/Pump Motor drive transmission to the Pump Unit side 
are shown below.
Note : Rotation of the motor in the clockwise direction as seen from the Motor Pinion 
Gear is considered "clockwise".
 Pump Unit
Ink is sucked from head nozzles by having the pump driven through the 
cap (closed). This performs normal ink absorption, initial ink charge, 
cleaning, etc. Waste ink from the pump is sent to the Maintenance Tank 
through 2 small pipes.
 Head Cleaner
A structure of offsetting rubber and felt is used. By wiping/rubbing, ink and 
dirt adhering to the head nozzle surface is brushed off.
 Cap Assembly
When not printing, the Print Head (should) rest on the Cap Assembly to 
ensure that the nozzles don't clog. Also, the Print Head is in the capped 
position during ink charging, cleaning, and so on.
 Flushing Box
This receives ink ejected during flushing (dummy printing). The flushed ink 
flows through the pipe to the Maintenance Tank.
 Maintenance Tank (Waste Ink Absorber)
This receives waste ink discharged from the Pump Unit and Flushing Box. 
Waste ink is accumulated in a sponge in the Maintenance Tank.
 Pump Phase Sensor
A transmissive photosensor is used, which is installed inside the Pump 
Unit. This uses the interrupting plate in the Pump Unit to detect the rotation 
angle of the pump.
Figure 2-13. Pump Phase Sensor
Table 2-5. ASF/Pump Motor Rotation Directions and Functions
ASF/Pump Motor Rotation 
Direction
Function
Clockwise
• Pump suction
• Wiper set
Counterclockwise
• Pump release
• Wiper reset
Pump Phase Sensor
Interrupting Plate