Epson 7000 service manual Printer Mechanism Operation Outline, Carriage Mechanism, Print Speed

EPSON Stylus Pro 7000 Revision B

2.3 Printer Mechanism Operation Outline

This section describes the various parts of the printer mechanism and how those parts work.

2.3.1 Carriage Mechanism

The carriage speed is determined by a software servo system. This software servo is a closed-loop system where the CR motor (a DC motor) must provide constant torque to keep the carriage speed even. For this purpose a timing fence (or step ruler) and an encoder sensor are employed to measure the carriage speed/location and to provide feedback to the motor controller accordingly.

†Print Control

The carriage speed during printing is described below.

Table 2-3. Print Speed

Print Mode	Carriage Speed
720dpi & Normal M/W	200cps
4 Pass FOL printing	300cps
unidirectional	400cps

Note: Due to the carriage’s quick acceleration process, even after the heads reach and maintain normal speed, they are not stable enough to print for the next 10mm.

†Stop Control (stop position)

The encoder determines the carriage position by counting the dark stripes on the Step Ruler. When the carriage reaches the predetermined position (depends on paper width), the carriage stops. To make sure the carriage has come to a complete stop, the printer checks the encoder for a certain time (in-position time-out) to make sure no signal is generated.

†CR Motor Abnormality Detection

The software servo sends a series of pulses to the CR Motor to drive the carriage a certain distance (depends on current operation, paper size, and so on). At the same time the encoder measures the distance

the carriage travels. If the position of the carriage according to the Software Servo is different from the position according to the encoder, a fatal error occurs (Service Call 00010005).

See page 60 for details on carriage sensors and other parts.

Operating Principles Printer Mechanism Operation Outline 69