Epson Stylus Photo 950, Service Manual

Page: 41 / 191

EPSON Stylus PHOTO 950 Revision A
OPERATING PRINCIPLES Printer Mechanism 41
†
Step 5 : How to Operate Paper Return Lever
Following is the operation principles mentioned how to operate paper return lever.
12. Once you remove the "silence gear", you can see the "cam gear" which has a role
for pushing down the "paper return transmission lever.
13. This "cam lever" is always jointed with both the "silence gear" and "super gear
28.8" (for driving LD roller on ASF).
14. When the "silence cam" rotates to counter clockwise, the "cam gear" will rotate to
clockwise. And a part of circle arc (cam) on the "cam gear" pushes down the
"paper return transmission lever". And paper return lever will be laid to guide a top
paper to the printer internal.
Figure 2-23. Silence Cam mechanism (9)
2.2.4.1 Pump Mechanism
The pump mechanism draws up ink from the printhead and from the cap assembly. In
addition, there is also a head cleaning wiper located inside the cap assembly. An
outline of the operation of the pump mechanism is given below.
The drive force for the pump mechanism is provided by a 4-phase 48-pole PM-type
stepping motor which is used as the pump motor. The specifications for this pump
motor are given below.
The Pump unit and Wiper mechanism drives according to the Pump motor rotational
direction, as shown in the following table.
NOTE: (*1) Pump operating direction : CW refers to clockwise operation when
looking from the motor output shaft.
C H E C K
P O I N T
There are two alignments on the right side of the ASF to get a
correct timing for driving paper load operation and ASF reset
operation.
A part of circle arc of
the “Silence cam”
Paper return
lever shaft
Paper return transmission lever
Cam gear
Table 2-5. Pump motor Specifications
Item Description
Type 4-phase 48-pole PM-type Stepping Motor
Drive Method Bipolar 2-2 phase, 1-2 constant current drive
Drive Voltage +42V +/- 5% (DRV IC voltage)
Coil Resistance 10
Ω
+/- 10% (per phase at 25 degree)
Inductance 10.5mH +/- 20% (1kH 1Vrms)
Table 2-6. Pump unit functions
Pump motor
rotational directions
(*1)
Pump unit functions
Clockwise
• Absorbs ink by the pump unit
• Sets the wiper
Counterclockwise
• Release ink by the pump unit
• Resets the wiper