WHY KYOCERA ENTERED INTO INKJET HEAD BIZ ?

[Anonymous]

Why Kyocera Entered Into Inkjet Head Biz?
Kyocera Corp developed an inkjet head for commercial printers and will make it a business in April 2008.
Kyocera has the largest share (a little less than 50%) of the world market for the heads for thermal transfer printers, the company said. Also, the company engages in the businesses of photoreceptors, LED heads and so forth for electrophotographic printers.

Kyocera will strengthen the business related to commercial printers by introducing the new inkjet head. I interviewed Hisamitsu Sakai, the company’s general manager of the Inkjet Division, and Sumio Arima, the company’s deputy manager of the Printing Device Sales Department, Corporate Thin Film Components Group.Why did you enter the business of inkjet heads?We consider that there is a large potential market for the commercial inkjet printers that are suited for printing a wide variety of images in small quantities and can print on demand without using a plate.The market size for inkjet printing, including printing equipments and inks, is only about ¥3 trillion (US$30 billion). But, the market for the printing business as a whole is large. For example, the market size for general printing, which uses a plate, is reportedly ¥70 trillion (including equipments and inks).Though printing equipments that use a plate are not suited for printing a wide variety of images in small quantities or for on-demand printing, commercial inkjet printers have a broader range of applications (Fig 1). Also, they will create demand for those new applications, expanding the print market.For example, recently, various types of ads and coupons, in addition to the card holder’s name and the detailed statement, are printed on credit-card bills. The name and the statement are different from person to person, but the ads and coupons are the same due to a limited printing cost.If commercial inkjet printers are used, it is possible to print ads and coupons that are different from person to person. And it will increase the value of the ads and, thus, boost the demand for printing.We already had many business talks. The new print head will be mounted in a printer developed by Miyakoshi Printing Machinery Co Ltd, who helped us test the head. Also, we are conducting negotiations with several dozen companies.

The new inkjet head is targeted at the printers used in those business fields. And we solved the problems of inkjet heads.What kind of problems did they have?There have been three major problems in using inkjet printers for commercial printing, slow print speed, bad image quality and low durability. For example, offset printing machines, which are often used in commercial printing, have a printing speed of 150m/min for general use and 1,000m/min for printing newspapers and others. The speeds of electrophotographic printers are 60-90m/min.In the case of inkjet printers, those with high image quality, 300-600dpi, have a printing speed of about 60m/min. Some inkjet printers for commercial use are as fast as 300m/min. But they are monochrome, and their resolution is as low as 150dpi.However, our new inkjet head has a printing speed of 75m/min. Its resolution is 600dpi. So, we achieved both high resolution and high speed for commercial printing. When the inkjet heads are arranged in two rows, the printing speed can be 150m/min, equivalent to the speed of general offset printing machines.

How did you solve the problems?
We increased the number of ink nozzles and enabled each nozzle to discharge about 30,000 ink droplets per minute. We increased the width of the inkjet head to 108mm, one of the widest in the industry, expanding the area that can be printed at one time (Fig 2). As a result, each inkjet head has 2,656 nozzles. Also, the ink channels are designed so that they do not get clogged with ink.

It is a piezo print head, which discharges inks by expansion and contraction of piezoelectric elements. In general, it is difficult to increase the resolution of piezo inkjet printers because a piezoelectric element has to be set in each nozzle and, to enhance the resolution, it has to be finely processed.To solve this problem, we decided to use ceramic flat plates, which are piezoelectric materials. Many electrodes are formed on a thin and flat ceramic plate, and the plate is set on top of the tank that stores ink (Fig 3). In other words, several piezoelectric elements are accumulated on a ceramic flat plate (Fig 4).The ceramic plate is densely mounted with electrodes, but the plate itself is not finely processed. Therefore, it is relatively easy to increase the resolution. We have already obtained a patent for this technique of using a flat plate.We improved the ceramic material too. We cannot reveal the details of the material, but the new material is more responsive and generates more power when a voltage is applied. Our strength lies in ceramic materials, and we took advantage of it.The ceramic plate is about 20µm thick, and the amount of displacement is about 100nm when a voltage is applied. The width of the ink channels that flow from the ink tank to each nozzle is several dozen micrometers. The inkjet head has a total of 2,656 piezoelectric elements on four ceramic flat plates (Fig 5).

You cooperated with Brother Industries Ltd to develop the inkjet head.
Though we have the know-how in thermal transfer printers and electrophotographic printers, we had to start the inkjet printer business from scratch. So we cooperated with Brother Industries, a pioneer in that field.Brother Industries, whose strength lies in its inkjet technologies, and Kyocera, who has the advantage of piezoelectric material technologies, complemented each other in developing the basic technology for the new inkjet head. Not only our company but also Brother Industries can use the newly developed technology.The development period is five years, from 2002 to 2007. After that, we conducted reliability tests for the inkjet head. We had verification experiments, for several months, where printed paper could often be as long as 100km per day and confirmed that the image quality does not deteriorate.

What is your future plan?
We will further improve the resolution and print speed. We have the advantage of dealing with ceramic materials. The resolution of 600dpi is still low compared with conventional printing technologies. We look to enhance the resolution to 1,200dpi.If the arrangement of the inkjet heads is changed, it is possible to have 1,200dpi at this point. However, it would require an accuracy of a few micrometers to set the inkjet heads to the device. If we can achieve 1,200dpi by improving the head, we do not have to deal with this problem.As for the print speed, we would not like to define a specific goal at this moment. There are some technological constraints on piezo inkjet printers. So we have to find those limitations first.

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April 2, 2008 at 2:34 PM