There have been cases such as with Seiren Co., Ltd.(Japan), already being successful in making a profit with an array of slow inkjet printers simultaneously printing the same designs.

The faster each unit can print, the smaller the cost of investment in facility improvements, and the greater the menace to those who hold firm to conventional printing methods.

However, whether high-speed inkjet printing can express delicate color shades and designs remains an issue yet to be resolved.

There are a number of matters that still require further research before the realization of high-speed inkjet printing.

Inkjet printing is expected to polarize into two separate methods, the YMCK and the 'special color system'. In the quest for future inkjet printing, it is necessary beforehand to understand the two methods in detail.

The following is based on a lecture given by Mr. Yoshitaka. Kitao, on the YMCK method and the 'special color system'.

Yoshitaka Kitao explained about the polarization of inkjet printing.

Yoshitaka Kitao, manager of the dyeing department of the Textile Technology Center, the Kyoto Municipal Industrial Research Institute, pointed out there was a polarization in inkjet printing, "Until today, inkjet printing mostly depended on the YMCK inkjet dot technology that requires extremely fine nozzles, however, from 2000, more and more people will realize that the special color inkjet method can bring about as good a finished quality as screen printing."

Since Kitao tested inkjet printing many times from a neutral stance, what he claimed got some credibility. He emphasized, "From my experience of researching and testing inkjet printing at the Textile Technology Center, the Kyoto Municipal Industrial Research Institute and inspecting inkjet printing machines exhibited at ITMA '99, I strongly feel that inkjet printing will come to use diverse methods."

Mr. Yoshitaka Kitao pointed out the polarization of inkjet printing in the meeting held at Nihon Senshoku Kako Dogyo kai (the Japanese Dyeing & Finishing Industry Association).

Kitao also explains how it is going to branch off into different methods, "Even screen printing for textiles, known today, started to branch off into roller printing, rotary screen printing, auto flat bed screen printing and hand printing in the last half of the 20th century. So, why won't inkjet printing based on digital technology vary in its procedures in the same way?"

Kitao makes a clear comparison between the YMCK system and the special color system using tables.

Kitao said the following at Nihon Senshoku Kako Dogyo Kai (the Japanese Dyeing & Finishing Industry Association) held in Osaka, Japan on December 3rd 1999:

Inkjet printing mainly requires the YMCK inkjet printing system, which is effective in expressing picture-like color images on paper or making cloth calendars with picture-like color images.

Table 1 picks up inkjet textile printing machines which branched off from the extremely fine dot method for color pictures on paper.

Table 1. List of inkjet printing machines exhibited at ITMA '99 (Paris)

In Japan, there has recently been a new system developed for pursuing the special color system that can bring about as good a quality as screen printing. See the image at the bottom of Figure 1.

<Figure 1>

In a word, EPSON's inkjet printing on paper, requires more than 1000 dpi of resolution. The finer quality you want to achieve, the purer inks or dyestuffs will be required.

The idea of the special color system that can lead to a screen printing taste, seen in the bottom of Figure 1, differs from the YMCK inkjet printing that emphasizes extremely fine quality depending on the spray of inks and the fixing conditions on cloths. The main feature of the system is using 12 special colors.

With the method, color quality similar to screen printing can be obtained. In the special color system, the nozzle that sprays ink does not need to be fine.

In my opinion, about 300dpi is necessary for textiles, and radically speaking about 180dpi of dye liquid may be sufficient. With nozzles about that range, expensive pure inks may be unnecessary.

If there is much emphasis on inks, although this is an extreme example, it will be necessary to examine the correlation between processes including pre-treatment and aftertreatment.

The YMCK inkjet printing system, a major procedure to obtain extremely fine images on paper, relies on the development of extremely fine nozzles, however, inkjet processes that take account of dpi and the ink dot layers suitable for textiles have been increasing recently. In the special color inkjet printing system, there is an attempt to enlarge the hole of the nozzle.

In the 21st century, inkjet printing will be polarized: methods that require extremely fine nozzles; and methods that aim at the special color system or methods based on the idea of the special color system. Each direction will branch off into various procedures that can be interpreted in many ways.

The YMCK inkjet system and the special color inkjet system will be the original branches for such derivations.

I came to the above point when I was making a list of the comparisons of printing methods (as in Table 2) through testing with inkjet test machines such as ENCAD etc at the Textile Technology Center, the Kyoto Municipal Industrial Research Institute.

Table 2 shows the comparison of advantages and disadvantages in (1) the YMCK inkjet system, (2) the special color system and (3) screen printing. It sums up the comparison of cost for each color ink.

Table 2. Comparison of each printing method

Colors listed in Table 2 are reactive dyestuffs.

(1) The YMCK inkjet printing system requires pure inks. Ink cost perof cloth is high. Compared with the cost for dyestuffs and color pastes used in screen printing, this is much more expensive.

However, in the YMCK inkjet printing system, environmental costs are low.

(2) The special color inkjet printing system can use dyes that are used in screen printing. In order to greatly improve the output speed of this method, dye makers should develop appropriate and economical dyes that can improve clogged nozzles. This way we will be able to achieve further development in the special color system.

However, Table 2 is illustrated based on the evaluation of traditional methods. As I mentioned earlier, I think that both the YMCK inkjet printing system and the special color system will keep developing thanks to the development of pretreatment and aftertreatment of inkjet printing.

Since Table 2 does not include observations following such a viewpoint, it is difficult to decide which method is superior relying only on data shown in Table 2. Please be aware that the data only cover a small portion.There is news that from 2000 the special color inkjet printing system will improve its output speed. When this is achieved, screen printers often considered irrelevant to the field of digital printing will have advantages.

Kitao covered various contents from many angles so it is difficult to list all the information here, however, he did not say that screen printing in its entirety will be replaced with digital printing.

Division of printing in Kyoto has led to uncomfortable circumstances.

Kitao emphasized that if we digitally print out samples through choosing colors and patterns on CAD, which is economically similar to screen printing, screen printers will have a lot of advantages.

In the future, not only printers will adopt the inkjet printing system but also those who design and plan printed products.

As such the traditional way of planning printed products will change. In the city of Kyoto, the printing process is divided into screen making, printing, steam-rinsing and general finishing among factories. There is no doubt that it is the time to seriously get ready for what is going to happen to printing factories due to the development of inkjet printing. In the case of factories based on divided businesses in Kyoto, there are still not many factories which have not adopted CAD, however, there is going to be a problem with SCM (the Supply Chain Management system) unless systems that can manage recommendations for printed colors and patterns using CAD are adopted.

Compared with dip dyeing and continuous dyeing, printing will be easily influenced by SCM. Kitao emphasized that if printing only on reception of orders is continued, it will lead to extremely bad circumstances.

This is because the low reaches of the textile industry have already been emphasizing the necessity for a change in merchandizing activities, production and sales in response to customers, rather than just selling finished products to producers.

Table 3. Correlation of each printing method

The time length for which consumers think that something is stylish is very short.

This idea was confirmed when the apparel field's conventional wisdom in which autumn products are lined up in the middle of August collapsed. Only clothes that will be worn in that season should be stocked, has become the new conventional wisdom of apparel stores, department stores, boutiques and mass merchandizing stores.

In the case of World, 70 % of its products supplied each season would be interim production and 30% would be market production. Unsold products can lead to an increase in the quantity of stock, and they cannot be sold even as bargains. As far as printed clothing goods are concerned, consumers feel that something is "in" for only a short time each season.

Retailers ignore printed goods delivered late. This ratio has recently kept increasing.

Printing factories and printing screen companies need to quickly suggest design plans and colors & patterns to apparel stores and department stores, which are really close to consumers, for their very survival.

Otherwise, they will put their survival at risk. That is why Kitao's emphasis on suggesting colors and patterns with CAD is so plausible.

Especially in the case of Kyoto (Japan) where there are so many kinds of divided printing businesses, it is, first of all, necessary to adopt CAD in order to increase the value of their existence. It is not too much to say that somehow, somewhere, someway, something's got to give.