Overview - Epson PH890 Service Manual

EPSON Stylus Photo 890/1290

2.1 Overview

This section describes the operating principles of the printer mechanism and electrical
circuit boards. The major components of the EPSON Stylus Photo 890/1290 are:
o
Printer mechanism: Stylus Photo 890:
Stylus Photo 1290:
o
Main board:
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Stylus Photo 890 : C393MAIN-C/C393MAIN-B
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Stylus Photo 1290: C393MAIN/C393MAIN-B
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Power supply board: C378PSB/PSE Board
PRINTER MECHANISM
Unlike other EPSON ink jet printers, the EPSON Stylus Photo 890/1290 uses a DC
motor as power source. The DC motor enables the printer to lower noise during
printing. Table 2-1 shows various motor types used in the printer and their applications.
Table 2-1. Motor Types and Corresponding Applications
Motor Name Type
DC motor with
CR motor
brush
DC motor with
PF motor
brush
Pump/ASF 4-Phase / 48-pole
motor stepping motor
OPERATING PRINCIPLES
M4T12
M4S61
Table 2-2.
Application / Feature
Drives the carriage making little noise. Works with
a linear scale to monitor motor's operating
condition.
Supplies power to drive paper feeding rollers used to
send paper at specified speeds and load/eject paper.
To monitor paper feeding pitch, a loop scale is
attached beside the high-precision gear.
Sends drive for pump operation and paper feeding
from ASF. Since this is a stepping motor, it has no
scales or photo sensors that are used to monitor
motor's operating condition.
The basic structure of the printer mechanism is mostly common to the Stylus COLOR
400, except that the Stylus Photo 890/1290 uses a Pump/ASF motor. With this motor
equipped, the paper loading mechanism and the pumping mechanisms are
independently driven, which allows the printer to offer higher throughput.
Figure 2-1 shows the printer mechanism block diagram for the Stylus Photo 890/1290.
Intermittent Gear
PF Motor Pinion
PF Motor
Flashing Window
(at 80th or 136th column)
Photo Interrupter (Encoder)
Notched Roller
Carriage Unit
Printhead
Timing Belt
Cap Unit
(without a valve)
Pump Unit
CR Guide Shaft
PF Roller
Liner Scale
Figure 2-1. Printer Mechanism Block Diagram
Overview
Revision B
Rotary Encoder
PF Drive Gear (high precision)
Photo Interrupter (Encoder)
Detector Wheel
ASF Sensor
LD Roller Shaft
Loading Rollers
PE Sensor
Pump/ASF Motor
ASF/Pump Disengage
CR Motor
Gear Train
PG Lever
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