Interviews > L-COA > Interview(1/6)

L-COA: Enabling unprecedented high-speed, high-resolution printing

Highlights of the new imagePROGRAF series include the Lucia 12-color pigment ink system, an ultra high 2400x1200 dpi resolution, and extremely fast output. These printers can print A2 posters in as little as 48 seconds. At the heart of this printer is L-COA (Large-format printer COmmon Architecture), a new image processor that reconciles the conflicting demands of superior image quality and extremely fast output. How is L-COA different from convetional image processors?

—— What does L-COA make possible in the new imagePROGRAF series printers incorporating the technology? Yoshida  I think it's clear when you look at a poster or banner from these printers for yourself. First, you notice the stunning image quality, which comes from taking full advantage of a 12-color ink system. That's the point I would emphasize.
Hosokawa  And the fact that this exceptional image quality is possible at high speeds. Superior image quality at very high speeds... L-COA stands apart by achieving both.—— L-COA is described primarily as an image processor. The term "image processor" calls to mind a dedicated LSI chip or device that does image data processing, implemented separately from the computer CPU, for faster image processing. Can L-COA do what it does just because it's a faster chip? Yoshida  No. There's more. The L-COA processor controls all the functions required by a large-format printer. This includes image processing and the creation of print data, as well as arranging the dots and driving the heads. It's an optimal controller for the overall printer. Think of it as a sophisticated brain, designed to unleash higher performance from imagePROGRAF printers.

But summing it up as a mere 'controller' undersells the staggeringly complex control it makes possible for the imagePROGRAF series.—— Because of the 12-color ink system? Hosokawa  That's one factor. In the iPF5000, for example, it would take about 3 gigabytes just to store all the data required to translate RGB information from software into 12 colors of ink for an A0 poster. Since generating data on this scale and storing it in advance isn't practical, data is generated on the spot during printing. On top of having to work with a large number of parameters, the data must be generated in real-time with limited memory. And, in addition to that, the output rate of the printer has to be reasonably fast.—— Converting software data to print data alone is process intensive, but L-COA also controls the drive mechanisms, doesn't it?
Yoshida

Having four times the number of ink nozzles doesn't mean the control processing can take four times longer. (Yoshida)
Yoshida  That's right. For example, the 12-color imagePROGRAF models have two one-inch wide heads, which have 2,560 nozzles per ink color, six colors per head. For two heads, that's a total of 30,720 nozzles. That's four times the usual number. And when you consider the minute size of the ink droplets applied by each head (as small as 4 picoliters, or 4.0 x 10-12 liters) and the pinpoint accuracy required, you begin to see the enormous number of calculations required for control.
—— We introduced the topic of ink droplet control in a previous article. (See The Minds Behind the Magic: The W8400 Large-Format Inkjet Printer.) Precise control over such large print areas... All I can say is you're doing something truly amazing. More amazing still, you wouldn't settle for slower output rates.Yoshida  We couldn't. Four times the number of ink nozzles isn't a license for the control processing to take four times longer.

Particulary since imagePROGRAF printers are used mainly in poster and graphic art production, as well as the printing of CAD data and similar graphics, a slower printer has a direct impact on client productivity.—— Then what technologies do you harness for faster output? Minami  One solution was integration onto a single controller chip. In previous engines (for driving heads, controlling paper, and so on), control was distributed across several chips. But this approach is inherently slower, due to the time-lag in transmission among the chips. This is why we integrated engines and other systems (like those for creating print data) onto a single controller chip. This approach also gives faster access to shared memory, and overall it has boosted speed tremendously.Yoshida  Integration on a single chip also helped keep costs under control. That was another goal. The chip delivers about five times the performance of conventional devices, but that wouldn't justify a cost five times higher.—— For some time, there was a trade-off between superior image quality and high-speed output. Choose one, and you sacrifice the other. That has been the prevailing state of affairs, something users were resigned to. To offer both at once... that sounds a bit hard to believe, like a dream come true. Yoshida  People say large-format printers are slow, but in fact, their processing speed itself isn't slow at all. It's just that these printers cover enormous print areas, so they seem to take longer.—— So with L-COA, your goal was to dispel this idea through faster output while offering revolutionary high-resolution printing, right?
Single-chip integration of all processors eliminates transmission standby and eliminates the need for a bus and the associated bottlenecks. The result: faster signal processing.

Single-chip integration of all processors eliminates transmission standby and eliminates the need for a bus and the associated bottlenecks. The result: faster signal processing.