Paper Advance Detector Mechanism - Epson LQ-670 Service Manual

2.1.4.2 Paper Advance Detector Mechanism

Paper advance detector mechanism consists of PW detector and PE (rear/front) detectors.
The function of this mechanism is to feedback information about monitoring paper edges, paper width and
paper jam, and to control paper advance. The detector's reading operation is constantly performed. The
timing to feedback the red signals is necessarily selected by CPU according to the operation of PF motor
and CR motor. The table below shows specification of the detectors and their functions.
Figure 2-5. Paper Advance Detector Mechanism
Detectors
PW detector
PE detectors (Rear/Front)
Front paper detector only
Rev. A
Table 2-5. Detector Function and Operation
Operation
Paper width measurement (detects
right and left edges)
Paper top edge detector(detects
top and bottom edges)
Detects if there is any paper or not
Detects top and bottom margin
Detects if there is any paper or not
Detects paper top margin
LQ-670 Service Manual
Function
Determines right and left margin
Determines top and bottom margin
Detects paper jam after checking
paper loading and ejecting.
Determines top and bottom margin
Detects paper jam and paper out (if
PW detector does not detect the
paper out) after checking paper
loading and ejecting.
Front entry in case of cut sheet
auto feed
2-7