Overview; Printer Mechanism; Printhead Mechanism - Epson Stylus Photo 870 Service Manual

EPSON Stylus Photo 870/1270

2.1 Overview

This chapter describes the operating principles of the printer
mechanism, the carriage mechanism, and the electrical circuit boards.
The printer includes the following features:
! DC motors for paper feeding and carriage control (see
Feeding Mechanism" on page 8 and
page 7)
! Encoder strip and wheel for precise carriage movement and paper
feeding (see "Carriage Mechanism"
Feeding Mechanism" on page 8)
! Determination of the carriage's home position without using a
sensor (see "Home Position Detection (Capping Position
Detection)" on page 18)

2.2 Printer Mechanism

The EPSON Stylus Photo 870/1270 printers use DC motors for their
power source. DC motors enable the printers to produce much less
noise and less vibration, and therefore greater print accuracy.
Table 2-1 describes the various motor functions.
Table 2-1. Motor Functions
Motor name Type
Carriage motor DC with brushes
Paper feed DC with brushes
motor
Pump/ASF 4-Phase 48-pole
motor stepper motor
"Paper
"Carriage Mechanism"
on page 7 and "Paper
Function
Moves the carriage with minimal noise and
vibration. An encoder strip detects the
carriage's position.
• Drives the paper feed roller and loads and
ejects paper.
• Operates the carriage lock lever.
• An encoder wheel monitors rotation of the
paper feed roller.
Drives both the ink pump and the auto sheet
feeder. Because it is a stepper motor, it has no
sensor to monitor the motor's position.
The basic structure of the printer mechanism is similar to the EPSON
Stylus COLOR 400/600/440/640/740, except that the EPSON Stylus
Photo 870/1270 use a Pump/ASF motor. This motor drives only the
paper loading and pumping mechanisms (but not the paper feed
roller), providing higher throughput.

2.2.1 Printhead Mechanism

on
The basic operating principles of the printhead are the same as
previous models that use an on-demand U-CHIP head, as shown in
Figure 2-1.
Ink cartridge sensor actuator
Nozzle plate
The printhead includes the following parts:
! Needle and filter
If any dirt or dust were absorbed into the printhead, the nozzles
could clog and block ink flow. To prevent this, a filter is installed
below the cartridge needle to filter the ink.
! Cavity
The ink absorbed from the ink cartridge goes through the filter and
is stored temporarily in the cavity until the PZTs are driven.
Chapter 2 Technical Overview
Nozzle selector board
Ink cartridge
Needle
Filter
Cavity
PZT
Figure 2-1. Printhead Mechanism
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