Gemini Industries Printer user manual

Gemini User’s Manual

Paper

“Needle” pin

Sprlng

-

	Platen
	Pln gulde
r	Iron core I ‘IL
$-

I

Ribbon guide

Clapper

\’ Bobbin

Printer solenoid

Figure 6-2. This side-view schematic of the print-head mechanism shows how electrical signals to the solenoid cause the clapper to “fire” the needle-like pin that impacts the ribbon/paper/p/a ten. After the solenoid releases the clapper, a spring returns the pin to its original position.

Gemini’s built-in “computer” reads the ASCII code instructions sent by your computer and directs the print head to discharge the correct pins in the proper order. The result of this “hiring” and “firing” is the printed characters produced by Gemini _ onto your paper.

Consider, if you will, the process of printing an uppercase letter “H”(see Figure6-3). Because the print head is bidirectional (can print right to left, and left to right), Gemini can start the “H” from either side.

In this example, the top seven pins fire simultaneously to print one side of the letter. Then, the print head moves across the paper, and pin number four fires three times to create the horizontal line. Finally, the top seven pins fire simultaneously again to complete the othervertical line. Aside from the amazing fact that the entire printing operation just described can take place in approximately one-hundred and twentyth of a second, all this activity is caused by a single ASCII code signal.

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