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1.1.3 DETECTION MECHANISM
As
shown
in Figure,
the
detection
mechanism
consists of the slit plate, slit mask, and slit mask
spring (which are part of the printing wheel ass'y) as
well as the timing detector ass'y. It generates Timing
signals that correspond
to type positions on the
printing wheel, Timing signals for detecting the end of
each print cycle, and Timing signals for detecting the
cutoff position for the power supply to the motor.
The slit plate is provided with two types of slits ;
(1) 12 slits that correspond to the type positions (TO to
T12), (2) one wider slit that is unrelated to the type
positions
(TS). To eliminate
unnecessary
Timing
signals, the slit mask rotates freely on the printing
whee! shaft so that the masking section of the slit
mask is controlled by the slit mask spring as follows ;
During the standby and character selection phases,
the slit mask permits passage of the light emitted by
the LED to the photo IC. During the printing and return
phases, it obstructs the light emitted by the LED.
When slit TS which corresponds to Timing signal TS
is positioned along the optical path between the LED
and the photo IC, the slit mask again permits the light
to pass.
Consequently,
only two types of Timing
signals are generated. The 13 Timing signals TO to
T12 are generated
during the character selection
phase, and the Timing signal TS is generated at the
end of the return phase.
Frame T
Shit mask
Printing wheel
shatt
Slit mask spring
Slit mask's masking
section
Daily Check
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2.2 MAINTENANCE
,,
2.2.1 CLEANING
Removing Dirt or Stains
Wipe off the soiled sections using alcohol or benzine.
8
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ai
Removing Dirt, Scraps, and Dust
Use a vacuum cleaner to carefully draw out all foreign
particles
from
every
part
of
the
printer
is
recommended.
NOTE :
@
Never use thinner, trichloroethylene nor ketone
solvents, as such use they may deteriorate or
damage the
plastic or rubber parts.
@
Check the remaining lubrication at each cleaned
area,
and
perform
additional
lubrication
as
required
(see subsection
2.3.3, " Lubrication
Points" )
2.2.2 INSPECTION
The maintenance and inspection procedures for this
printer are grouped into two categories : 1) daily
checks that can be easily performed by the operator
of the printer during the course of daily work, and
2)
periodic
checks
that can
be performed
only by
persons having a through understanding of the printer
mechanisms.
These procedures should be implemented according
to the technical level of the person conducting them.
Check to see if the printer is always being maintained in optimum conditions. If any dissatisfactory points are
discovered, they shall be remedied.
Periodic Check
Every six months, periodic maintenance and inspection of the following points should be conducted ;
Check Item
Adhesior/penetration of
dirt, paperbscraps or
dust to the printer parts
See section 2.3.2,
Lubrication Requirements
Lubrication status
Printing and ribbon
feeding
Ribbon is properly f
Standard
No excessive adhesion of dirt, paper scraps or dust on the moving parts.
No penetration by foreign matter.
the printer.
Paper guide path
No paper dust, etc. should be obstructing the paper guides.
Shape of the springs
No deformed springs.
Replace any deformed springs
No print defects, such as defaced, missing, or unexpected characters.
f
2
a
No abnormally narrow or uneven line spacing
Smooth operation of each lever and spool gear.
Ribbon winding is reversed when a low ribbon supply is detected.
Shape
of each part
No part should be worn, deformed, or otherwise damaged.
Replace any faulty
parts.
—30-
Repair Method
Use a vacuum cleaner to carefully
remove all foreign particles with
Remove any foreign matter using
tweezers.
See section 2.3.3,
Lubrication Points
See section 2.5.3,
Repair Guidelines
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