Canon global

Ink is the direct key to improving the image quality of a printer. What are the characteristics of the inks you developed this time?

Takayama

We didn't improve just the color performance of each ink, but also realized marked improvements in reproducibility and gradation through the combination of inks. When printing in color, even details in dark areas are reproduced, and when printing in monochrome, subtle nuances in dark and light areas are reproduced better than in the past.

What did you do to achieve this?

A transparent ink called Chroma Optimizer was used for the first time in the PRO-1 and the PRO-10. What does it do?

Takayama

The pigment inks used in the PRO-1 and the PRO-10 offer powerful printing results, like what you'd see in a painting, but dye inks realize better luster. We newly developed Chroma Optimizer to achieve greater gloss with pigment inks. It coats the ink droplets on the surface of the paper. This not only increases the glossiness, but also improves the depth of black by suppressing the diffused reflection of light.

Kudo

To achieve this effect, the Chroma Optimizer must be properly ejected from the nozzles and coat the colored ink uniformly. But you have to keep in mind that we were dealing with an “invisible man” (laughs). We had a lot of trouble with verification and evaluation.

Yazawa

The use of Chroma Optimizer meant that we needed to carry out development based on a new concept even in terms of controlling image quality, which gave us a hard time.

Takayama

But the difficulties encountered in the development of the pigment inks were nothing like that (laughs). Orders flew back and forth between each group. Every day we'd repeat a process of trial and error.

I see. Compared to that, how did things go during the development of the inks for the PRO-100, which uses eight colors of dye ink?

Takayama

The dye inks for the PRO-100 have been significantly improved for better coloring performance, resistance to the elements and transparency. We didn't cut any corners (laughs).

Yazawa

The PRO-1 offers the highest level of performance specs while the PRO-10, as an affordable pigment ink printer, is next in terms of the color gamut it realizes, and then there's the PRO-100, a dye-ink printer for users particular about image quality that offers excellent transparency and gloss. Through the PIXMA PRO lineup, we'd like to provide photographers with a wide selection of choices to satisfy their ever-growing range of needs.

Now that the subject of print heads has come up, I'd like to ask you some questions Mr. Kudo. The number of nozzles used in the PRO-1 is 1.6 times the number of the previous model. Was that to increase printing speed?

Kudo

That's right. It's approximately 1.8 times faster. Since the nozzle diameter is the same, it was necessary to keep the dots uniform in accordance with the increased length of the print head.

As for ensuring this uniformity, there's no way to avoid a temperature response with regard to the principle of ejecting ink through the formation of bubbles, right?

Kudo

That's right. When printing, the size of the bubbles increases as the temperature of the print head rises and, as a result, printing quality deteriorates. That's why we introduced a method enabling real-time control. The system responds to changes in the temperature of the print head during printing and constantly adjusts the energy used to discharge the ink from the nozzle.

Overview of real-time drive control

Yazawa

In previous models, control of the temperature response was only carried out when the print head reversed direction at the left and right edges. But this time around we realized that high image quality required that we control it in real time.

Kudo

For a printer to achieve high image quality, the ink and the print head need to advance hand in hand. As such, to ensure optimal performance of the print head, we correct the control value on each PRO-1 when it's shipped.

If you're able to achieve the uniform ejection of quality ink from the print head, next would be controlling image quality. What were you able to improve the most this time?

Yazawa

We established a method for determining the optimal combination of inks and placement of ink droplets on the paper surface, which we applied across the entire PIXMA PRO lineup. We call it the OIG System and it controls image quality by determining optimal settings for ink ejection with regard to when (ink should be ejected), which inks (should be used), where (ink droplets should be placed on the surface of the paper), and how much should be ejected for each paper type.

Conceptual diagram of the OIG System

The combinations of the number of inks selected and the percentages of each color are countless. Wasn't finding the right answer a difficult problem?

Yazawa

Yes, it was. We felt that we needed to adopt a more systematic approach than in the past, but the development of this system itself was actually quite challenging. We made it possible to ascertain numerical values for image elements such as color performance, tonal gradation, glossiness and black density, after which we created an enormous database by measuring actual print results. The system is based upon this analysis.

I see. But now that you can use the OIG System, it must be easier to support changes in ink under development.

Yazawa

Exactly. We've improved the development efficiency of image quality control and evaluating image quality has become more objective.