Operating Principles; Printer Mechanism Operating Principles; Printing Mechanism - Epson DLQ-3000 Service Manual

2.1 Printer Mechanism Operating Principles

This chapter describes the operating principles of the printer mechanism (M-5P60).

2.1.1 Printing Mechanism

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Printhead
The printing mechanism of this printer is composed of the 24-pin impact dot printhead
and a ribbon mask. The printhead has 12 pin wires in each of 2 rows, which are aligned
in an rhombic layout. (See Figure 1-2 in Chapter 1.) Each wire has its own drive coil.
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Printing process
1. The printing signal transmitted from controller circuit to the head driver circuit is
converted into the head drive voltage, which energizes a corresponding coil. The
energized coil then magnetizes the iron core.
2. The magnetized iron core draws the actuating plate which joins to the dot wire. This
movement rushes the wire toward the platen.
3. When the dot causes impact to the platen, it presses the ribbon to the paper, where a
dot prints.
4. When the coil energizing is terminated, the iron core, losing magnetic force, is
returned to the standby position by the bounce of the platen and tension of the
actuating spring.
The printing mechanism has an integrated thermistor to detect head temperatures. The
detected temperature is converted into an electrical signal and fed back to the controller
circuit. This information as well as paper thickness is used as a basis for determining
printhead driving mode to ensure high printing quality. It is particularly important to keep the
head temperature at a proper level constantly to minimize burning and deterioration of the
dot wires in the printhead, which are caused by the rise in the head temperatures due to
continuous printing. When the head temperature is below the specified level, the
appropriate driving mode is selected based on the detected temperature to keep the wires
respondent. (Refer to Section 1.3.1 in Chapter 1.) See Table 2-1 in Page 2-2 for the
printhead specification.
Rev. A
Figure 2-1. Structure of the printhead

Operating Principles

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