HP 2500C Series - Manual (Page 127)

Functional Overview 6-7
Paper Paths and Components
Output Management
Output Mechanism Schematic
Star-wheels
There are two rows of star-wheels, main and secondary. The main row contains ten sets
of active starwheels (each set consists of 2 starwheels) and two passive starwheels .
Active starwheels are preloaded by starwheel springs and are driven by output roller. The
linear speed of starwheels is 2 % greater than that of drive roller thus creating paper
stiffness to maintain the critical parameter pps distance. Also, once the media leaves the
outpinch rollers, these starwheels become the only driving force to eject the media to the
output tray. Two passive starwheels (not shown in figure) are provided to control A/A4
media shape such a way that the bow shape created by ramp does not propagate into the
print zone. There are four sets of secondary starwheels in between the main row
starwheels and cockle ribs. Locating the outer profile of these starwheels at the tangential
line connecting the main row active starwheels and cockle rib tip make sure that media is
not lifted above the tangential line and also the media does not touch the chassis once it
leaves outpinch roller after printing.
carriage chassis
cockle rib
platen
ramp
output shaft
separator
holder-starwheel(sec)
holder-starwheel(main)
starwheel(main)
starwheel(secondary)