Epson Stylus Pro 4450 - Suction Fans; Modes

EPSON Stylus Pro 4400/4450/4800/4880/4880C Revision C
Operating Principles Printer Mechanism Components 133
 PF Motor (DC motor)
With drive from the PF Motor, the grid of the loop scale installed above
both PF Rollers is read by the Encoder Sensor, and feedback control is
based on the output pulse. This control maintains high printing precision.
 Suction Fans
Suction Fans are mounted in the center inside the printer. This is designed
to provide smooth paper feeding (prevents floating) by pulling the paper
onto the platen surface by drawing air through multiple punched holes in
the platen on the underside of the paper path and directing it toward the
bottom of the printer body. Control of blowing force (rotation Duty control)
for the fans is based on the printer operating condition (at paper set, during
printing, etc.) and paper type.
Figure 2-29. Suction Fans
The sensors used in the paper feed mechanism are described below.
 PF Encoder Sensor
Mounted at the left side of the printer, the sensor's pulse output (2
channels) corresponds to the slit position on the PF Scale and is used for
servo control of the PF Motor and for formation of the PTS (Print Timing
Signal). Resolution is 1/360 inch.
 PE Sensor
This reflective photosensor is mounted at the right side rear surface of the
printer. This triggers the no paper condition when the paper trailing edge is
detected and triggers paper setting start operations (start of suction fans,
etc.) when the leading edge is detected during paper setting.
 Paper Lever/P_THICK Sensor (P_THICK, P_THICK_0.3)
This transmissive photosensor is mounted at the right side rear surface of
the printer. Paper thickness is detected during paper setting by the change
in movement of the paper thickness detection lever of the Driven Roller
Unit.
Threshold values for paper thickness is set for 0.3~0.4mm (P_THICK0.3
Sensor) and 0.8~0.9mm (P_THICK Sensor), and the sensor operates
when the Paper Lever goes down.
Set detection values for the sensors are 0.3mm and 0.8mm, corresponding to
the up/down position of the Paper Lever. Combined detection of both sensors
detects the paper lever as up.
Suction Fans
Table 2-9. Modes
Paper Thickness
Shield Plate Sensor Output
P_THICK_0.3 P_THICK P_THICK_0.3 P_THICK
Less than 0.3mm No (open) No (open) L L
0.4mm or more
0.8mm or less
No (open) Yes (closed) L H
0.9mm or more
1.8mm or less
Yes (closed) Yes (closed) H H
Connector not
connected
––HH
Cancel increased
pressure (Hi-Up)
Yes (closed) No (open) H L