Epson Stylus Pro 5000, Service Manual, Page: 60 / 780

Stylus Pro5000 Chapter2 Operating Principles
Rev.A
2-21
2.1.1.13 Friction Release Mechanism
In the previously used paper feed mechanism, which was applied for Stylus
Color 1520 and Stylus Color 3000, the paper feed roller always contacts with
the paper feed support roller located under the paper feed roller. In this
condition, as the printing on the presently moving the paper gets closer to
the end, since the friction between paper feed roller and the paper feed
support roller is all released at the paper ending edge, strictly speaking,
there is a possibility that the paper feed pitch varies slightly.
D o w n
P a p e r F e e d R o l l e r
P a p e r F e e d
S u p p o r t R o l l e r
[ P r e v i o u s M o d e l s ]
[ P r e v i o u s M o d e l s ]
F r i c t i o n i s
r e l e a s e d
Figure 2-25. Concept of Friction Release
[Explaining the operation]
The gear train, which sets or releases the friction with paper feed support
roller, depends on the sub roller driven gear train. As it is mentioned in the
section 2.1.1.7 Hopper 5mm Down Mechanism, when the pump/ASF motor
rotates, the cam gear always rotates too, regardless the motor’s rotational
direction. This cam gear not only pushes or pulls the lever in order to
encourage the lifter gear train to be released, but also conveys the motive
power to the transmission gear to encourage the paper feed support roller to
move up and down in the frame inside.
Sun Gear
Planetary Gear
Cam Gear
Sub Roller Driven Gear
Figure 2-26. Transmitting the motive power to the Cam Gear
Since the sub roller is not supposed to rotate forward, this gear train are not
able to rotate in reverse, unless the pump/ASF motor rotates backward,
using planetary gears and conveys the motive power. On the other hand,
when the pump/ASF motor rotates forward, the motive power is not
transmitted to the Sub Roller Driven gear but only to the cam gear. If this
cam gear keeps rotating, it will come off eventually, since there is a limit for
up and down operation by the paper feed support roller.
In order to prevent this, a part of gear teeth of the cam gear is removed and
this avoids conveying the unnecessary motive power from the planetary
gears.