Epson Stylus Photo 925, Service Manual

Page: 28 / 167

EPSON Stylus Photo 925 Revision A
Operating Principles Overview 28
2.1 Overview
This section describes the operating principles of the printer mechanism and electrical
circuit boards. The Stylus PHOTO 925 has the following boards:
V
Main board: C475 MAIN
V
Power supply board: C408 PSB/PSE
V
Panel board: C475 PNL
2.1.1 Printer Mechanism
This printer consists of the Print Head, Carriage Mechanism, Paper Feeding
Mechanism, Paper Loading Mechanism, Ink System (Pump Mechanism, Cap
Mechanism, and Carriage Lock Mechanism), and the Cutter Mechanism which has
newly designed for this printer.
DC motors are employed as the CR Motor and PF Motor. By use of DC motors, this
printer ensures improved printing accuracy and paper feed accuracy and greatly
reduced noise during printing.
The Cutter Mechanism newly designed for this printer is also driven by a DC motor.
Figure 2-1. Printer Mechanism
Table 2-1.Motors
Motor Type Application/Function
CR Motor
DC motor with
brush
Drives the carriage. Almost no driving sound. A linear
scale is mounted to facilitate checking the current
position of the carriage.
PF Motor
DC motor with
brush
Drives the Paper Feed Roller at paper regular feeding,
paper supply and paper ejection. To facilitate checking
the paper feed pitch, a loop scale is mounted on the
surface of a high-precision gear.
Cutter Motor
DC motor with
brush
Drives the Cutter Mechanism. Two photosensors are
mounted to detect the position of the driven Cutter
Unit.
ASF/Pump
Motor
4-phase 48-pole
PM type stepping
motor
Runs for pump driving and for paper loading from ASF.
This motor, a stepping motor, does not require mounting
of any scale or photosensor for detection of the drive
position.
ASF Hopper Spring
CR Motor
Paper Separation Pad
ASF/Pump Motor
CR Unit
Loop Scale
Timing Belt
Pump Unit
Photo-interrupter (Encoder)
CR Lock Lever
PF Motor
Adjust Lever
Paper Eject
Roller
Photo-interrupter
(Encoder)
Carriage
Guide Shaft
ASF Hopper
Linear Scale
LD Roller
PE Sensor
Clutch Mechanism
Cap unit
Change Lever
Paper Feed Back Plate
Cutter Motor
CT Sensor
(Home-80)
Cutter Unit
(Movable
CT Sensor
(Home-0)