Printing Method; Carriage Mechanism - Epson Stylus Photo895 Service Manual

EPSON Stylus PHOTO 895/785EPX/915/825

2.1.2.2 Printing Method

For print dot system, Stylus PHOTO 895/785EXP/915/825 has the following two kinds
of printing modes.
Multiple shot printing
Variable dot printing
The above two printing modes are automatically selected depending on the media and
the resolution setting of the printer driver. The following explains each printing mode.
Multiple shot printing
This printing mode is developed to improve the print quality on plain paper or
transparencies in low resolution. The multiple shot printing mode uses normal dot
and the number of dot shots varies from 1 shot to maximum 3 shots depending on
the print data to enable sharp image output even in a low resolution.
Variable dot printing
This printing mode is developed to improve the print quality on exclusive paper.
This mode is basically the same as variable dot printing mode used on other
products ; micro dot, middle dot, and large dot compose this mode. Print dot size
varies according to print data and this mode enables even sharper image output on
exclusive paper.
Operating Principles

2.1.3 Carriage Mechanism

The carriage mechanism consists of Carriage motor (CR motor), Carriage unit
(including printhead), CR timing belt, CR guide shaft, platen gap adjustment
mechanism, parallelism adjustment mechanism CR guide frame, CR home detector
(HP/PE sensor) etc. The carriage mechanism moves the carriage back and forth
according to the drive from the carriage motor. The following stepping motor is
mounted to drive CR mechanism. (See the table below.)
Table 2-1. Carriage Motor Specification
Items
Type 4-Phase/ 200-Pole HB Stepping motor
Drive Voltage +42 V +/ - 5% (DRV IC voltage)
7.8 Ω +/ - 10% (per phase at 25 degree)
Coil Resistance
Inductance 14 mH +/ - 20%(1KH 1VmA)
Drive Method Bi-Polar drive
Driver IC LB11847
The drive from CR motor is transferred to the CR unit via CR timing belt. And the CR
home position is detected with the HP sensor. This sensor is available as CR HP
detector only in the HP (home position) detection sequence & pump operation
sequence.
Overview
Revision B
Specifications
35