Commentary & Analysis
Drupa 2012, the Inkjet Drupa…again? A closer look at HP
In this second article of the series, David looks at HP’s production inkjet offerings and applications.
By David Zwang
Published: October 31, 2011
HP has been in the inkjet printer market since the mid 1970’s, when the company brought the first commercially successful thermal inkjet technology to market. I would imagine that most of you have had an HP inkjet printer on your desk at one point in time, maybe even still do. So to say they understand inkjet would be an understatement.
HP hasn’t sat still since the 1970’s, and in 2006 the company commercialized its “Scalable Printing Technology.” This important development has allowed HP to bring to market new products including office machines, photo kiosks, wide format and production printers all around the same, although continually developing, printhead technology. While the early HP inkjet cartridges housed 50 nozzles, the heads installed in the current production inkjet portfolio have 10,560 nozzles per printhead, so they have come a long way.
During a recent tour of HP’s IHPS headquarters in San Diego, I got a chance to truly see how deep their involvement in inkjet really is. At this facility, in addition to administrative and marketing functions, they also do a great deal of research. Onsite, HP manufactures inkjet heads and develops proprietary inks. They also do research and work with the paper manufacturers to develop “inkjet friendly” papers, so they have amazing control of the entire imaging process.
A primer on the HP Thermal Inkjet technology
At the core of any printing process is the imaging technology. In the case of HP, it’s all about a thermofluidic process, where “nothing moves but the ink itself.” In the printhead, a tiny heater vaporizes a thin film of ink. A vapor bubble fills the chamber like a piston to force ink through a nozzle. Air bubbles are also forced out on every drop ejection cycle. The HP Thermal Inkjet platform has extremely high drop rates, of up to 48,000 drops per second per nozzle, using a high nozzle density of 1,200 nozzles per column inch. The design includes a fault tolerance system that compensates for any faulty nozzles. The presses use HP developed and manufactured water-based pigment inks. HP has also recently added a MICR option, with an HP specially designed printhead and ink.
Water-based inks have very low VOC emissions, are non-flammable and non-combustible with no hazardous air pollutants intentionally added, which translates into a safe and environmentally friendly printing technology. Of course, since water is a major component of the ink, it does create the potential for other issues. All inks, even the inks used in offset printing, need to ‘bond’ to the substrate to create a good adhesion. If the bonding didn’t occur, the ink would easily rub off. Since water-based inks can and will absorb into many non-treated substrates, HP uses an optional ‘Bonding Agent’ inline to pretreat the substrate at every pixel the pigment ink will print. This pretreating allows the ink to bond to the surface without being absorbed too deeply. By pretreating only pixels that will receive ink, waste of the bonding agent is minimized. The benefit here is the ability to print on a wide range of standard uncoated or plain papers with good edge acuity, low strike through and vivid colors.
In order to support the growing production inkjet market, paper manufacturers are producing inkjet compatible papers. These papers would not require the use of a bonding agent, and in fact can produce better reproductions as well. However, while it can vary depending on coverage, the use of a bonding agent can also lead to lower costs than purchasing pretreated substrates, and additionally it optimizes smudge and water resistance.
The Press Transport
The presses were designed to look more open than the others in the growing field, which tend to look boxy, more like a bigger version of the toner-based machines we are all familiar with. HP’s current lineup starts with the 20.5-inch wide T200, which prints at up to 400 ft./min in monochrome and 200 ft./min. in color, and has an optional upgrade to print up to 400 ft./min with full monochrome and lower color density. The line goes up to the T400 which boasts a 42-inch width and a 600 ft./min. throughput. While most production inkjet machines have provisions for printhead upgrades as they become available, the HP transport system has been developed to allow for field installed upgrades to increase throughput as well. The HP T200 and T400 presses have configurable inline IR and hot forced air heaters to ensure that the paper is dry, and also allow for two-sided print at the high rate of speed at which they are operating. The presses are built for heavy usage, with the T400 duty cycle rated at 140 million equivalent letter size images per month at 600 ft./min.
As would be expected, HP has worked with many third-party partners to ensure a full range of inline finishing options, including a “zero-speed splicer” option for quick roll changeovers, as well as unwind and rewind units, etc. That being said, many users are finding that nearline solutions make more sense in their production environments.
The Front End
The front end driving these presses is the HP SmartStream Ultra Print Server. Since HP is also a server manufacturer, the system is based on its own hardware architecture. At the heart is a Global Graphics Harlequin RIP, which can support most of the standard PDF/X formats, PDF/VT, and AFP/IPDS with a third-party solution. The ability to manage the press, as well as any incoming static or variable jobs at machine rated speeds requires a very powerful and expandable computing system. Depending upon which press you choose as well as your workflow levels and requirements, servers can currently be configured to meet the most demanding requirements from a Level 1, which includes 1 server blade and 4 RIPS, to a Level 10 which hosts 20 server blades and 120 RIPS..
Putting it to use
HP sells these systems with a “Non-Click”/ A La Carte model. So you are paying for consumables based on your usage, which is controlled by your type of work. The user replaceable consumables include ink, bonding agent, printheads, and web wipe cassettes. HP has even developed an application that will predetermine the coverage for each job and estimate your costs.
As is the case with most of the production inkjet devices on the market, as discussed in the last article, HP is targeting the Book, Direct Mail, Transaction (through Pitney Bowes), and Newspaper markets with its offerings..
One production inkjet customer is King Printing in Lowell, Mass. King is primarily a short-run book printer that services book publishers, small businesses, and self-published authors. Typical projects include books in quantities of 1 to 50,000. The interesting thing about King is that at first look, it almost appears as if they have one of every production inkjet press on the market, although in reality they don’t. However, they have been using production inkjet since 2008, and they do have enough of them to understand their individual strengths and roles in a production environment. More importantly, they understand how to make money using them.
King originally installed an HP T300 in 2010, and soon realized that they could benefit from a 50% increase in speed with the T350 field upgrade. According to Adi Chinai, the Managing Director at King Printing, “When we first installed the HP T300 last year, we gained a stable and very capable production platform that allowed us to manage incredible volumes. With the T350, HP used its technological leadership to make an even more robust platform, one that is helping us rewrite the economics of color in short-run publishing and book manufacturing.”
King still uses both sheetfed and web offset, sheetfed B&W and Color EP devices, in addition to its production inkjet equipment. As a result of the equipment mix, and workload, finishing is all near-line to offer the flexibility they need to support all of their equipment.
In the next article, I will continue by looking at the Kodak production inkjet offerings and applications. In each subsequent article we will explore a different vendor’s offerings.