Service manual

EPSON Stylus Photo 870/1270 Revision B
OPERATING PRINCIPLES Overview 33
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 870/1270 are:
"
Printer mechanism: Stylus Photo 870: M4T10
Stylus Photo 1270: M4S60
"
Main board: C304MAIN Board
"
Power supply board: C298PSB/PSE Board
PRINTER MECHANISM
Unlike other EPSON ink jet printers, the EPSON Stylus Photo 870/1270 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
The basic structure of the printer mechanism is mostly common to the
Stylus COLOR 400, except that the Stylus Photo 870/1270 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 870/1270.
Figure 2-1. Printer Mechanism Block Diagram
Motor Name Type Application / Feature
CR motor
DC motor with
brush
Drives the carriage making little noise.
Works with a linear scale to monitor motor’s
operating condition.
PF motor
DC motor with
brush
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.
Pump/ASF
motor
4-Phase / 48-
pole stepping
motor
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.
Intermittent Gear
PF Motor Pinion
PF Motor
Flashing Window
(at 80th or 136th column)
Photo Interrupter (Encoder)
Notched Roller
Rotary Encoder
PF Drive Gear (high precision)
ASF Sensor
Detector Wheel
LD Roller Shaft
Loading Rollers
PE Sensor
Pump/ASF Motor
CR Motor
PG Lever
Liner Scale
PF Roller
CR Guide Shaft
Pump Unit
Cap Unit
(without a valve)
Timing Belt
Printhead
Carriage Unit
ASF/Pump
Disengage Gear Train
Photo Interrupter (Encoder)