Commentary & Analysis
Drupa 2012, the Inkjet Drupa…again? A closer look at Screen
This series by David L. Zwang focuses on current production inkjet products and their application in the market today. This series will run every 3 weeks leading up to drupa 2012. In this seventh article of the series, David looks at Screen, its production inkjet offerings and applications.
By David Zwang
Published: February 24, 2012
Dainippon Screen Manufacturing Co., Ltd., is based in Kyoto, Japan. The company’s roots date back to its founding in 1868 as Ishida Kyokuzan Printing Works. In 1918, it started its evolution from a printing company to a manufacturer when receiving its first patent for “Transparent Film Letterpress for Lithographic Transfer,” and starting a manufacturing company known as Ishida Films. In 1934, the company created glass screens for photographic reproduction of halftone plates. In 1943, Dainippon Screen Mfg. Co, Ltd., was established in an effort to focus on manufacturing tools for photographic reproduction. These tools included horizontal process cameras, a wide range of film-based contact screens to replace the glass screens developed earlier, and many other tools. As an aside, my first exposure to Screen was in the early 1970’s when I purchased one of its horizontal process cameras and a set of contact screens for my printing company. Oh…the good old days…
In 1957, Screen began to diversify, supplying electronic components to television camera manufacturers based on some of the technology developed in its screen business. In 1962, Screen began marketing Fairchild Inc’s scanner in Japan. This was their entrée into electronics for photographic reproduction. From there, Screen began to develop more technology internally. This included an electronic plate engraver, an extensive line of internally developed scanners, electronic page makeup systems, digital film recorders and platemakers. Screen launched its first press, the Truepress 544, a digital offset press, in 1998. The company continued to expand its product lines related to prepress and print with both hardware and software systems and it hasn’t stopped. Screen introduced its first production inkjet press, the continuous feed Truepress Jet 520, in 2005, and then introduced the first of many wide format UV printers a year later. Most recently Screen has introduced the Truepress JetSX, a sheetfed duplexing production inkjet printer, the subject of the remainder of this article.
In addition to continued development in graphic arts software and hardware manufacturing, Screen still has a strong presence in the semiconductor manufacturing machine business.
In this article, we will look at the Screen production inkjet offerings. These would include both continuous and sheetfed presses.
A primer on Screen Truepress Jet Production Inkjet technology
At the core of the Screen inkjet presses are the Seiko Epson piezo Drop on Demand (DOD) inkjet heads in the Truepress Jet520 series. As discussed in the Ricoh article, these are the same heads used in the Ricoh Infoprint 5000 presses. Ricoh and Screen don’t publish full detail on these proprietary heads, so I will give you what information I have been able to pull together through my own research in addition to what they have told me. According to Seiko Epson, the piezo elements in these inkjet heads change shape according to the voltage applied, which enables precise control of ink drop size and ejection from the inkjet head. However, a piezo element by itself is not enough to facilitate the precise, even propulsion of the ink onto the media. Through meniscus control, it is possible for the piezo element to control the movement of the meniscus (the ink surface in the nozzle). This technology allows both high-precision impact point control and perfectly spherical dots and is a key element in the precise levels of ink ejection control characteristic of Micro Piezo Technology. The heads can print a four level grayscale at 2 bits per spot and offer stochastic screening, so the multi-drop technology is also able to generate extremely smooth gradations.
The inkjet heads are mounted in a single-pass multiple-head array. The distances between the inkjet heads for each color, as well as the distances from the inkjet heads to the substrate, are short, ensuring exceptional color-to-color registration. The presses can support CMYK dye and pigment inks depending on the press model and configuration. The heads on the continuous feed presses can print at up to 720 x 720 dpi with a 4 picoliter drop size, with 4 level grayscale depending on the press model and configuration chosen. The Truepress Jet520EX models each have 20 printheads, the Jet520 has 40 printheads, and the Jet520ZZ has 80. The inks come in 3 liter sealed containers to ensure degassing and a clean smooth flow with longer head life. The presses support two containers for each color, except for the Jet520ZZ which supports four containers per color. The ZZ containers are also hot swappable to ensure that its high speed production is not affected.
Truepress Jet520 presses have an automated head cleaning system that is triggered by the operator. A test sheet is printed, automatically scanned, and any head or nozzle problems are detected and addressed with a cleaning or alert. Screen recommends performing this maintenance function either at shift changes or each day.
The new sheetfed JetSX model uses a different head that is 1440 x 1440 dpi and can print at a resolution up to 1440 x 1440 dpi with a 2 picoliter drop size. The special SX proprietary water-based pigment ink is contract manufactured for Screen in Japan. The SX press self-calibrates at the beginning of the run to ensure head and voltage alignment. It also self-cleans and self-caps the heads when not in use. Interestingly, the heads are quick flushed after each sheet. While Screen has found that the MTBF of the heads on its Truepress Jet520 line is about 24 months regardless of hours of usage or whether you are using dye or pigment inks, it’s a bit too early to tell what the head life is on new SX. However, they are both sourced from Epson and will probably have a comparable life.
The Press Transport
Screen offers two primary configurations for its Truepress Jet line of production inkjet presses: continuous feed models, and a new sheetfed offering. We will look at both configurations.
The continuous feed Truepress Jet520 presses come in four models, each one targeted to different speed and application. They can all be purchased to print simplex with one engine, duplex with 2 engines, or in the case of the TP J 520 and the TP J 520EX Mono, a single engine duplex (SED). There are two TP J 520EX models that both print water-based dye inks, although the EX Mono also supports pigment; a monochrome press that can print up to 420 ft./min, and a color press that prints four process colors at up to 210 ft./min., depending on resolution. The TP J 520 and the TP J 520ZZ can print either dye or pigment process color inks. The TP J 520 prints up to 420 ft./min. at a maximum resolution of 720 x 720dpi. The TP J 520ZZ can print up to 721/ft./min., at a maximum resolution of 720 x 360 dpi.
As is the case with most of the production inkjet printers, there is an increasingly wide range of papers supported that includes newsprint, uncoated offset, laser and premium inkjet compatible papers from 64gsm to 157gsm. Screen does not pre-coat the paper. The TP J 520 line of presses use a quartz heated drum on the back surface of the paper to dry it after printing.
The press interfaces allow them to be compatible with most standard pre- and post-finishing equipment in the market. This supports the primary customer application requirements for statements, manuals, books, direct mail, etc.
The latest entry in the family is the Truepress JetSX, a full-color sheetfed variable printing system. It uses a single pass inkjet head unit. The transport system is not drum based like the Fujifilm J Press 720 sheetfed press. The TP J SX press uses a feeder and delivery very similar to that of an offset press. However, on this press the transport is more like those used in an electrophotographic press than an offset press. Screen uses a linear motor drive rotary vacuum table, with head stops and a side guide to move the sheets through the press. This transport, according to Screen, allows support for board media. In duplex mode, it uses a paper-reversing unit consisting of a transfer drum and a belt drive that brings the printed sheet back to the front of the machine to be sent back through again to print the reverse side. Interestingly, when there is a duplex operation, the pages that are printing on the front of the sheet are interspersed with the pages printing the back of the sheet, depending on when they return to the paper path for printing of the second side. Very interestingly, the press keeps track of which is which. You can also use the press to print variable data on sheets that were printed on an offset press.
The TP J SX can print at speeds of up to 1620 simplex sheets (6480 A4 size) per hour or 810 duplex sheets (3240 A4 size) per hour at 1440 x 720 dpi. The press can support from 8.3” x 11” to 20.8” x 29.1” with thickness from 0.1mm up to up to 12 pt. board in duplex mode, and 20 pt. board in simplex mode. While there is no pre-coat unit on this press, it has a post-coat unit that puts a thin spot coat on the image areas to seal and protect them. It also has an IR dryer to dry the sheet before delivery.
Screen Truepress Front Ends
Screen EQUIOS is the driver for the entire Screen Truepress line of presses. In addition to managing the press operation itself, it is the front-end workflow. It is a universal workflow application that has the Adobe PDF Print Engine (APPE) at its core. It supports CTP devices and presses with applications that include variable data processing (VDP), color management, and impositions, and it connects with many third party JDF-based devices for input and finishing.
Putting it to use
The three primary consumables for the presses are the inks, sponges, and on the SX, the post-coat. Screen offers a range of maintenance contract options depending on specific requirements.
The Screen Jet520 series has been in the field for more than 5 years in addition to being available in the (Ricoh) Infoprint 5000 configurations. In speaking with many owners of the presses, these are real workhorses that just keep running. The primary applications seem to be in book production, direct marketing and transactional print.
The JetSX is a new press just arriving on U.S. shores, and to date has no commercial experience. I will follow up on this and report once there has been an installation and some real world experience.
In the next article, I will continue this pre-drupa educational series by looking at Memjet and a few of its OEM partners, discussing how each of them are using the technology to address specific application requirements. The next two articles after the Memjet article will summarize what all of this information means and how you can use it to help you educate yourself on what production inkjet technology is here, what you can expect, and how you can utilize it in your business. You will also find this series useful if you are planning to attend drupa. It will help you sort out your priorities as you undertake the mega-experience that drupa always represents. Following and/or during drupa, watch WhatTheyThink for news on new announcements about production inkjet that we have not been able to cover in this pre-show series.