Epson EPL-6200, Service Manual

Page: 74 / 204

EPSON EPL-6200/EPL-6200L Revision A
Operating Principles Description of Mechanisms 74
2.2 Description of Mechanisms
2.2.1 Print Head (PH)
2.2.1.1 Entire Constitution
Scanning with the laser beam coming out of the Print Head is performed by the
polygon motor.
(See “Figure 2-7”)
2.2.1.2 Exposure Process
†
The laser beam from the print head creates an electrostatic latent image on the OPC
drum surface.
(See “Figure 2-8”)
†
The following control is performed in order to find the appropriate timing to print
the image.
„
When the printer receives the PRINT signal, the polygon motor and the main
motor operate, and paper feeding is started.
„
Upon passage of a specified period of time after the front end of the fed sheet
turns the paper feed sensor ON (TOD signal), the main control board sends
the VIDEO signal to the print head, and printing starts.
„
When moving on from the first line to the second line, the print starting
position is shifted down by delaying the VIDEO signal sending time
„
The Print Head incorporates the SOS sensor to unify the timing of the laser
emission for every line of main scanning.
Figure 2-7. Print Head Constitution
Figure 2-8. Exposure Process
Semi-conductor Laser
G1 Lens
G2 Lens
1st Mirror
SOS (Start of Scan) Sensor
Polygon Mirror
SOS Mirror
2nd Mirror
OPC Drum
Polygon Motor
Print Head Unit
Laser Diode
SOS (Start of Scan)
Sensor