Operating Principles Of Printer Mechanism; Head Carriage And Paper Feeding Mechanisms; Print Head; Ribbon Feeding Mechanism - Epson MX-80 Technical Manual

2.5 Operating Principles of Printer Mechanism
The M-3210 Printer Mechanism can be broadly divided into the following six functional
blocks.
(1) Print head mechanism
(2) Head carriage mechanism
(3) Paper feeding mechanism
(4) Ribbon feeding mechanism
(5) Detecting mechanism
(6) Frame section
2.5.1 Head carriage and paper feeding mechanisms
The operations of all the above mechanisms except the frame section are basically con-
trolled by the two stepper motors which are driven by two two-phase excitation signals. The
turning force from each motor is decelerated by a simple gear train and is conveyed to the
timing belt for head carriage driving or sprocket wheel for paper feeding, respectively. These
stepper motors are 4-phase, 4S-pole motors. The angle of revolution per phase of each
motor corresponds to the movement of the sprocket wheel or timing belt as follows:
(1) One pnase of paper feeding stepper motor ....... 1/216 inch (0 12 mm)
(2) One phase of carnage stepper motor ......................... 1/60 inch (042 mm)
2.5.2 Print head
The print head is the life and soul of the MX-SO dot matrix printer and serves as the neucleus
of the printer operations. The operating principle of the print head is simple as explained
below by referring to Fig. 2.24.
---~I
Dot wire
!
Magnetic pole
J
Fig. 2.24 Operation of Print Head
' - - - - - - - - - - -
Wnen tne current wltn a pulse wldtn of approx. 400 fJ,sec is applied to tne magnet, the mag-
netic actuator is attracted to the magnet, tnus causing tne collar portion of the dot wire to be
pushed out against tne force of tne spring. Tne clearance between the actuator and each dot
wire has been adjusted so that tne dot wire protrudes about 0.6 mm when Its collar portion is
pusned. The dot wire thus protruded in trle direction of the arrow strikes the paper through
the inked ribbon and is caused to return to its original position by the action of the spring and
the reaction of its impact agamst tne paper.
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