Epson Stylus Photo 720, Service Manual

Page: 39 / 154

EPSON Stylus Photo 720 / EPSON Stylus Photo EX3 Revision A
Operating Principles Overview 39
2.1.6 Ink System Mechanism
Ink system mechanism consists of pump unit (including CR lock mechanism) and
capping mechanism.
Ink system mechanism drives the pump unit that presses cap to the printhead and ejects
ink from ink cartridge, head cavity and cap to the waste ink pad.
CR lock mechanism assembled in the pump unit locks the printhead to prevent the head
from slipping off the capping position so that the printhead nozzle surface is kept clean
and wet.
2.1.6.1 Pump Unit and CR Lock Mechanism
The pump unit is driven by PF motor. PF motor drive is always transmitted to the paper
feeding mechanism and pump unit, and therefore pump unit and CR lock mechanism
drives according to the PF motor rotational direction, as shown in the table below.
Table 2-6. PF motor rotational direction & Ink System Mechanism
(*1): The PF Motor rotational direction = seen from the PF motor pinion gear.
Figure 2-9 shows the operating principles of the pump mechanism.
Figure 2-9. Pump Mechanism
Directions Corresponding ASF Functions
Clockwise (*1)
• Retracts the wiper.
• Releases the CR lock lever.
Counterclockwise (*1)
• Absorbs ink by the pump unit
• Sets the wiper.
• Sets CR lock lever
Tube squeezed
Tube released
Counterclockwise Clockwise