Large-Format Inkjet Printer The Story Behind the Development of the imagePROGRAF

The lineup for the graphic arts market is complete

POINT 1

Simultaneous development of four models with 12 pigment-based inks

Development themes: improving image quality, productivity and stable color reproduction

Canon launched a lineup of imagePROGRAF large-format inkjet printers equipped with 12-color ink systems (the iPF9400, iPF8400, iPF6450 and iPF6400) in the summer of 2012. Featuring LUCIA EX pigment-based inks, the models range in size from 24 inches to 60 inches. The launch rounded out Canon's lineup of large-format printers for the graphic arts market. What was the backdrop that led to the rollout of these products?

Hara
It's because the market has been steadily expanding, a market that Canon has led in developing.

What do you mean? Could you provide a little more detail?

Hara
There was always an underlying need for large-format inkjet printers in the graphic arts field for such applications as producing high-quality photos and artwork, high-resolution color proofs, and commercial posters. Until now, however, it seems that there were users who were not completely satisfied with the image quality, which hindered market expansion. But we turned things around in 2006 when we got a jump on the industry by launching a model featuring a 12-color pigment-based ink system. In addition, we significantly improved image quality with the introduction of LUCIA EX high-quality pigment-based inks in the iPF8300, which we released in 2010. That led to a real surge in growth for the graphic arts market.

Katsushi Hara

Area of development: Image processing

I see. So you aimed to further enhance functionality based on what was happening in the market. What was the concept behind the development this time around?

Watanabe
Well, we obviously had to surpass the performance of the earlier models, but we had three development themes. The first was to further improve image quality. This, of course, is a theme that always comes up when we develop new printers. The second was increasing productivity by boosting speed and reducing downtime. And the third was improving the stability of color reproduction.

Embracing challenges with uncompromising resolve

So what was each of you responsible for during development and what themes did you deal with? Let's start with you, Mr. Hara.

Hara
The biggest mission for my team was bringing out the color performance inherent in the high-performance inks while doubling print speed. We had to design the process and control it without any hiccups.

But image quality and speed are inversely proportional. If you simply doubled the speed without taking any other measures, the results would be disastrous, wouldn't they?

Hara
Exactly. It requires that the two inverse proportions be compatible at a very high level. We knew from the start that the development would be challenging, but any compromises by my team, no matter how minor, would not allow us to improve image quality, despite using the high-performance inks. I made sure that everyone in our team was strongly committed to not compromising in any way.

Watanabe
The mechanical development team also had that same commitment to not compromise during the process. On this project, I was responsible for the mechanical development of the iPF6450 and the iPF6400. The theme was to significantly boost productivity through high-speed printing and hot-swap ink tanks to allow for uninterrupted printing. In addition, we enabled the use of high-capacity ink tanks with approximately 2.3 times the capacity [of previous tanks]. Because these two models are smaller than the high-end iPF9400 and iPF8400, we faced some structural complications. There were also many other challenges and in the back of my mind I wondered whether we'd succeed or not (laughs). I was very anxious.

Shigeru Watanabe

Area of development: Mechanisms

I can imagine how you must have felt. How about you, Mr. Eiyama?

Eiyama
I admit that I was anxious (laughs). But, the truth is, I was excited about our assignment to develop a new high-precision color density sensor, and create a spectrophotometer SU-21 as an option.
I was confident that our team could definitely pull it off, so for me, the enjoyment and rewarding nature of the project far outweighed any concerns I had.

Was the sensor needed to improve color reproduction stability?

Eiyama
Yes, color calibration using this sensor reduces variations in color tone. It's impressive because it enables printing [across multiple printers] with uniform color performance, not only when using the same model, but even when using printers for different print sizes, provided they're part of the imagePROGRAF-series lineup with the same number of ink colors.

Mr. Yamamoto, you were responsible for development of the PC application bundled with the products, right? Did you see things differently from the other three?

Yamamoto
I was responsible for upgrading the PosterArtist poster-creation software. It can be used across the imagePROGRAF series, and because I've been involved in its development from the initial version, I decided that we couldn't make any compromises.

What, in particular, did you focus on?

Yamamoto
Improving usability. The main theme was making it much easier than in previous versions to create professional-quality poster designs, even without any design expertise.

POINT 2

The challenge of delivering both high image quality and high-speed performance

Patiently repeating tests to achieve high image quality

Now I'd like to ask you all a little more in depth about what you developed. Your first theme was improving image quality. How did you go about tackling this objective?

Hara
We focused on improving the print-control aspects of ink ejection while maintaining the high image quality made possible by LUCIA EX ink.

I heard that the LUCIA EX ink used in the previous models that were released in 2010 was well received by the market. What improvements were made to the earlier version of LUCIA ink?

Hara
Although pigment-based inks are able to produce more vivid colors than dye-based inks, colors may not appear as intended due to reflected or scattered light. It's a phenomenon that inevitably occurs because of the pigment particles that rest on the printed surface, but to minimize the effects of this drawback, we took countermeasures in terms of both the pigment material and print control.

What steps did you take for print control?

Hara
Inkjet printers express intended colors by overlapping different colored inks, and the order that each ink color is ejected is determined for each model. We changed this order from the one we used in previous models. The 12 colored inks used in the new printers all have different characteristics. To reduce the drawbacks caused by light, it's better to place some inks on the bottom layer; in other words, it's better if certain colors of ink are ejected first. And the opposite holds true for other colors of ink. We examined various combinations and found the ink-ejection order that was the least subject to the adverse effects of scattered and other types of light.

So you actually made printouts using different ink combinations and changing the ink-ejection order, and then measured the reflection of each one?

Hara
That's right. It was a dull and repetitive testing process (laughs). But there are no shortcuts to improving print image quality.

I see. So the deep blacks that they make possible, one of the characteristic of LUCIA EX ink, were achieved through such patient and tireless efforts.

Two approaches to boosting productivity

Your second theme during development was productivity. Simply put, productivity increases when you boost printing speed. The new models such as the iPF8400 realize impressive print speeds that are around double of previous models while offering improved image quality. What "magic" did you use to pull that off?

Watanabe
When an inkjet printer prints, the head travels back and forth over the same area of the paper several times and, once that area is finished, it moves on to the next area. A single print is created through the repetition of this process. So, by decreasing the number of passes the head needs to make for each area, we were able to reduce the amount of time needed to complete an entire print. For example, the time required could be halved by simply reducing the number of passes needed to cover a single area from, say, 16 to 8. In short, this makes it possible to double print speed. These products increase speed using this approach.

I see. So you just need to reduce the number of passes even if the head travels at the same speed. That seems simple after the fact, but I'm sure it wasn't easy to come up with that idea. Was it hard to improve image quality at the same time?

Hara
Yes, it was. It's the simple strategies that can be the hardest to implement (laughs). The reason the head passes over the same area is to improve image quality by correcting for banding and color irregularities. Reducing the number of passes means doing away with such important aspects.

How did you resolve this?

Hara
We examined the way the ink strikes the print surface and produced several-hundred patterns by printing over the same area. It was by doing this that we discovered what conditions need to be met to enable the same corrective benefits as before with half the number of passes. It was a long process of patient trial and error (laughs).

Another method for improving productivity is hot-swap ink tanks. Did this design prove difficult?

Watanabe
Hot-swap ink tanks, which let users replace ink tanks without having to stop printing, are made possible by incorporating secondary ink tanks between the [primary] ink tanks and the head. Running out of ink during print jobs not only wastes ink and paper, it also brings printing to a halt, which leads to substantial losses of time. But with hot-swap ink tanks, neither time nor ink is wasted. Since this feature was included in previous high-end models, such as the iPF8000 series, there was no need for new development. Introducing it in mid-range models, however, like the iPF6450 and the iPF6400, did present a challenge because these printers are smaller than the high-end models. There wasn't enough room to install secondary ink tanks inside the printers to begin with. So, in the end, we weren't able to reuse the design from the high-end models and eventually had to use a new design.

So it was harder to design them to enable the use of both standard ink tanks and the tanks with 2.3 times the capacity?

iPF6450/6400 ink tanks (Left: 130ml, Right: 300ml)

Watanabe
Yes, exactly. If you're starting from scratch and don't have to worry about the structure of the device, or the shape of the ink tanks or the previous models, there are any of a number of approaches you can take, but that wasn't something we were allowed to do. We needed to insert a tank that was 2.3 times the size of the original into a narrow space, and needed to ensure that it used the same mounting attachment as the standard tank. It sounds like a crazy requirement (laughs). We put our heads together and assembled prototype components, performing tests over and over again.

POINT 3

Improving usability in terms of both hardware and software

New development of density sensors for improved color-tone uniformity

Now I would like to ask about the third theme of development, which was improving the stability of color reproduction. Mr. Eiyama, it seems that the color density sensor your team developed led to a significant improvement in the color calibration management function. Why is color calibration necessary in the first place?

Eiyama
Even when using the same printer, color tones in printout will change after prolonged continuous use. And even if you line up multiple models of the same printer, each individual head will result in subtle variations in color tone. That's why color calibration is necessary: to ensure consistent colors.

Masato Eiyama

Area of development: Sensors

How do you go about doing that?

Eiyama
The printers automatically perform color calibration using a sensor that reads a chart printed on special paper and comparing printed colors with the way they should appear. In the products we released until now, such calibration was only performed among printers of the same model, but with these new models, we developed a high-sensitivity color density sensor that enables calibration between different imagePROGRAF series models.

What was the biggest challenge in increasing the accuracy of the sensor?

Eiyama
The printed chart is illuminated and a photo diode receives the reflected light but, because the surface of the chart contains ink, the paper gets bent in all sorts of directions. This means that the angle of the reflected light isn't uniform. This being the case, it isn't possible to attain accurate data, even if you increase the sensitivity of the photoreceptors.

I see. So, how did you resolve the problem?

Newly developed color-density sensor (image)

Eiyama
We made the range of the chart that's illuminated much smaller. By making the print area of the chart smaller as well as the area that bends, it's possible to ensure that the light that gets reflected approaches the light reflected from a flat surface. Development of the sensor really picked up once we realized this.

Didn't you also develop an optional spectrophotometer unit for measuring colorimetric value? Could you tell us about the role it plays?

iPF6450 Printer with Optional SU-21 Spectrophotometer Unit

Eiyama
Generally speaking, it plays two roles. The first is to automate color measurement in the work flow associated with color measurement of proofs and the like. And the second role has to do with the deep-rooted needs of customers to perform color calibration when using paper not produced by Canon. The SU-21 spectrophotometer unit obtains the necessary information so customers can perform calibration using the paper of their choice, and feeds this information back, playing a supporting role for the color density sensor. These dual roles serve to boost color-management convenience and productivity.

Significantly improving the usability of poster-creation software

One of the reasons why people use large-format printers is to create posters. But designing posters requires experience and knowhow; if you've never done it before, you're in trouble. Well ... this is what's generally believed, anyway. But PosterArtist poster-creation software turns this way of thinking on its head.

Yamamoto
Well, I usually don't like to boast (laughs), but I think you pretty much summed it up in what you just said. PosterArtist can be used with all imagePROGRAF models, but our latest version is something we're really proud of.

Alright, tell us about it.

Yamamoto
The software can basically be used in two different ways. One is the template approach, and the other is the auto-design approach. With the template approach, users choose the design template they like from among the approximately 200 available, and then complete the layout by assigning colors and inserting text, photos and illustrations. The software offers more than1,000 different photos and illustrations. Users can use any of these in their posters, or they can use their own.

PosterArtist
How to complete your own poster by 4 steps

What about the auto-design approach?

Yamamoto
Users simply follow the software's on-screen guidance, first choosing a design image, like Classy or Casual, then inputting the text, and then picking the photos and illustrations they want to use. The software then generates a variety of completed poster designs to choose from, each with a different color combination or layout. Users can use any of these as is, or make changes by altering, say, the color or the positioning of design elements.
Both of these methods were developed with a priority on usability, so users should be able to easily create their own posters.

Noriyuki Yamamoto

Area of development: Application software

What areas required the most ingenuity?

Yamamoto
It was setting the software up so that, when using the auto-design function, users can select the type of poster they want to match the purpose it's being designed for, like to announce an event, or promote a product or service. We incorporated a lot of the feedback we got from users of previous versions.

POINT 4

Development of new products through the coordination of technologies

Canon's strength lies in the company's coordination and reaffirmation of technologies

The release of these printers completes Canon's large-format printer lineup for the graphic arts market, but during development, were there any instances that struck you as "the Canon way" of doing things, or representing one of Canon's strengths?

Watanabe
It's something I feel every time we launch a new product, but the coordination of Canon technology is amazing. If necessary, we get involved in areas of technology other than the one we're in charge of.

Hara
I also feel there to be a culture of cooperation. From the standpoint of image-process design, it may be something I feel because of the broad range of related technologies, but we face quite a few situations that can only be resolved when everyone involved combines their strengths. The context that makes this possible is the company's commitment to image creation, from input to output, without cutting corners.

Watanabe
We were also able to overcome the various troubles and difficulties we faced just prior to production thanks to everyone working together.

Hara
That's right. At one point we discovered that, under certain conditions, banding would occur during printing. This was immediately dealt with and resolved, not just by the print-control team, but also by everyone from image processing design and even the mechanical design members. I've been involved in printer development for about 15 years, but that was one of the most difficult defects I ever had to deal with (laughs).

Mr. Eiyama, was technical coordination important in the development of the sensor?

Eiyama
Yes, it was. The color density sensor unit is only around the size of an eraser*, but it's packed with a variety of technologies like optics and circuitry. It also includes Canon proprietary technology that corrects for variances in sensitivity between individual sensors. It was this kind of coordination of technologies that made this high-performance sensor possible.

Yamamoto
This coordinating of technologies, or maybe I should say combining of technologies, also applies to software development. The development of the auto-design function required the combination of several slightly disparate elemental software technologies, such as rendering and layout technologies. Because elemental software technologies are also widely used in product segments other than printers, the ability to make practical use of them is a strength unique to Canon.

  • *
    The color density senor unit measures approx. 15 mm × 50 mm × 23 mm

We'd like even more users to discover the appeal of large-format printing

How would you like to see the imagePROGRAF series penetrate the market in the future?

Hara
We'd like users to take greater notice of various aspects of image quality, such as the breadth of the color-reproduction range, the sharpness of small text and fine lines, and the depth of the blacks that can be expressed. I look forward to a time when more people will be able to fully appreciate and enjoy the appeal of large-format printing, its impact and the warmth of the paper.

Yamamoto
PosterArtist is a software package that can be used by anyone; it requires absolutely no specialized design knowhow. Anyone who uses it will be able to better appreciate the value of the printers.

I hope that these printers will enjoy a wider user base.

Watanabe
Well, we'd really like for printing companies and output centers to give them a try. They'd soon be able to see just how good the image quality is and how fast they are. And another thing I hope they'd appreciate is the hot-swap ink tanks: no waste of time or ink. As printers for business use, they meet all the necessary requirements.

Any thoughts, Mr. Eiyama?

Eiyama
As Mr. Watanabe said, I think we've realized a product lineup that, comprehensively speaking, is worthy of high acclaim. They're well balanced in terms of the requirements of the market. I hope we get the support of a wide range of users who will turn to Canon when they're looking for a large-format printer.

Well, it is a strong lineup, so you may not have to wait long for that day to come. Thank you all for your time today.

Closing comment
Through today's discussion, we were clearly able to see that, in terms of image quality, productivity, color stability and usability, each area was given thorough attention during the development of these large-format printers. We also caught a glimpse of the ingenuity employed by the engineers as they struggled to carry out various improvements.

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Interview & Composition
Tadahiro Suda
Born in Fukushima prefecture in 1955. Became a freelance writer in 1990 after working as an editor at a news service and publisher, and managing an editing production agency. He is active in a wide range of publications, including management information journals and job-transfer publications. In recent years, he has contributed many articles to media portal sites, with the development of technology and products as one of his main areas of focus.

Developers interviewed

Katsushi Hara

Area of development:
Image processing

Shigeru Watanabe

Area of development:
Mechanisms

Masato Eiyama

Area of development:
Sensors

Noriyuki Yamamoto

Area of development:
Application software

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