Epson MX-80 Technical Manual page 37

2.5.3 Ribbon feeding mechanism
When the timing belt for head carriage driving rotates, a train of planetary pinions are rotated
by the belt driving pulley causing the ribbon driving gear intermeshing with one of the plane
tary pinion train to rotate to feed the inked ribbon in the cartridge case. Therefore, when the
head carriage is not in operation, ribbon feeding is not performed.
The inked ribbon in the cartridge case is an endless ribbon and is used until the ink impreg
nated in the ribbon depletes. When the printed characters are faint due to the ink depletion,
the cartridge case or just the endless ribbon in the cartridge case may be replaced. Replace
ment of the endless ribbon should be limited preferably to a maximum of 5 times per
cartridge case to maintain the disirable print quality for an extended period.
2.5.4 Detecting mechanism
The M-3210 has two main sensors to detect the printer operations; one to determine whether
or not the print head is at the left end home position to start printing and the other to deter
mine the position of the print head driven by the carriage stepper motor.
The home position sensor assembly is located at the lower left end of the M-3210 to deter
mine the home position of the print head. As the print head moves and approaches the
vicinity of the left end of the Printer, a signal is generated when the screen plate protruding
from the bottom of the print head passes across the photocoupler.
The PTS sensor board assembly is secured to the motor heat sink at the right part of the
M-3210. Like the home position sensor, a signal is generated when the slit disc which is pro
vided with slits along its circumference and coaxially secured to the timing belt motor shaft
.passes across the photocoupler.
2.5.5 Frame section
The frame section consists of two side frames and one base frame, all of which are of unique
sheet metal construction to minimize the weight of, as well as to miniaturize, the Printer
mechanism. Between the two side frames secured on both sides of the base frame,
mechanical components such as carriage assembly, paper feeding mechanism, ribbon
feeding mechanism, etc.. are compactly arranged to form the M-3210 printer mechanism.
9-94