Epson Stylus Color 640 Service Manual page 49

EPSON Stylus Color 440/640/740
2.1.1.3.1 Platen Gap Adjust Mechanism and Parallel adjustment
Mechanism
This mechanism can be set by the users and can prevent various
problems related to low image density or print with any dirt by changing
the positions of PG lever according to the paper types.
Table 2-4.
Platen Gap Adjust Lever Setting
Paper Lever Position
All Media Front
If you find any print Rear
problems
It is a major premise that parallel adjustment is done correctly for the
space between head and platen (PG adjustment value above) which
can be changed by platen gap adjustment. Parallel adjustment should
be done when the serviceman mounts the carriage guide shaft on the
printer mechanism during the production process or repair service. In
the adjustment, the space between parallel adjustment lever and gage
should be 1.04 mm.
Chapter 2 Operating Principles
PG adjustment value
0 mm
(1.04mm between head and platen)
0.7mm
(1.07mm between head and platen)
2.1.1.4 Paper Feed Mechanism and Pump Mechanism
Mechanisms that send the paper in the hopper to inside the printer and
perform constant paper feed in order to perform printing on the sent
paper are called paper feed mechanism as generic name. In the Stylus
Color 440/640/740, 4 phase hybrid type pulse motor is used in the PF
motor as a motive power motor as a motive power of the paper
mechanism and driving is done at 2-2, 1-2 phase drive method for
Stylus Color 440, 640 and at 2W1-2, W1-2, 1-2 and 2-2 phase drive
method for Stylus Color 740. This motor is not only used as a power
source for paper feed mechanism but also used as power source of
pump mechanism which is necessary for print head cleaning. By using
this pulse motor, it becomes possible to use high speed driver or
intermittent drive for the various paper feeds and pump operations such
as paper feed, slight paper feed, high and low speed absorption of
pump operations. Following tables show PF motor specifications and
control method at each mode.
Table 2-5. PF Motor Specifications (Stylus Color 440, 640)
Item
Motor type 4-phase/48-pole Stepping motor
Drive voltage 42VDC
Coil Resistance 7 Ohms
environment)
Drive frequency [Hz] 100-1990 Hz
Control method Bi-Pola Drive
Table 2-6. PF Motor Specifications (Stylus Color 740)
Motor type 4-phase/200-pole Stepping motor
Drive voltage 42VDC
Coil Resistance 8.8hms
environment)
Drive frequency [Hz] 100-3240 Hz
Control method Bi-Pola Drive
Revision A
Description
5%
10%(per 1 phase under 25 C
5%
10%(per 1 phase under 25 C
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