(c)Set the adequate ASCII code data to be printed. To obtain low logic level signals, connect the data transfer line required for printing (pin Nos. 2 to 9) to GND level (pin No. 33, etc.)

• Example of printing’?” “Z”=[5A]~=(0101. 1010)

In this case, connect pin Nos. 2, 4, 7 and 9 to pin No. 33.

5.Construction of MX-80 F/T

The EPSON MX-80 F/T Dot Matrix Printer consists of the following three major functional blocks.

(1)The model 3310 printer mechanism

(2)Control circuit board

(3)Power circuit

These three blocks are housed in a plastic case and are connected to one another.

5.1. Printer mechanism

The model 3310 printer mechanism has been developed by Shinshu Seiki with the technology in the precision and electronic industry fields amassed through its long association with SEIKO, manufacturer of the world-famous SEIKO watches.

The printer mechanism contains two stepper motors. One is to move the print head to the next print column position, and the other is to advance the paper.

(1) Stepper motor for head carriage

The stepper motor for head carriage is controlled under LSI “8041” called “slave CPU”. The CPU knows the current printing position at any given time, and the print head is stopped at the last printing position. Then, the CPU seeks the shortest travel way to the next print line.

This feature and bi-directional printing enable the Printer to perform the logical seeking function which minimizes the head travel time to the next print line.

(2)Stepper motor for paper feed

Paper is fed by the stepper motor, like the head carriage. One complete rotation of the stepper motor corresponds to 1/3 inch paper advance. In the MX-80 F/T, the operator can select any paper feed length under soft- ware control (described in detail later).

(3)Micro print head

The micro print head has 9 dot wires to form 9 X 9 dot matrix characters. 9 wires form more legible characters than those formed by 7 wires. The print head for the 3310 printer mechanism is quite compact.

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