It works like old typewriters. You align the corners of the paper and then clamp it.

Compare that, at the time, to the top of line of a Gerber (or 3M) plotter that was the only one able to handle 12+ ft. It used an array of sensors that at runtime adjusted the clamping-wheels pressure to keep the paper/vinyl roll aligned.

It was around $15-18K, while my Ioline was ~$1,300.

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Could you tell me more about your markers?