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CLUSTER PRINTING: one controller, many engines

Jul 1, 2002 12:00 AM

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Until recently, some desktop and workgroup printers were rejected for “real” production work because they lacked the necessary speed and print quality. But even as these barriers fell — monochrome printers have broken the 100-ppm mark — another obstacle remained. Few devices offered extensive production tools and utilities. Today, cluster-printing products are filling that void.

A clustered printing system consists of a group of printers controlled in parallel by a RIP and a common control system. In other words, a centralized management component provides a common interface and gateway to multiple printers. By distributing large jobs across multiple engines, or running multiple jobs concurrently, cluster-printing products treat a group of printers as one virtual printing system. A clustered system supports functions that some individual printers can't, such as scanning, cut-and-paste, page numbering and job accounting. (For some users' comments, see “Cluster printing: Strength in numbers,” May 2000, p. 62.)

Most cluster-printing systems support black-and-white and full-color devices. Some cluster products can even analyze an incoming job and automatically separate the color and black-and-white pages. Cluster products typically support the full spectrum of available printers, ranging from economical workgroup machines to high-volume equipment.


A steadily increasing percentage of digital toner-based equipment is sold network-ready, but these systems often lack the “brains” to tie it all together. That is where cluster-printing systems can help.

When purchasing a production-grade color copier or black-and-white production equipment, most buyers will also get a PC or workstation to go with it. These dedicated print servers are primarily responsible for establishing communications with the network and converting PostScript or PDF files into the internal raster format required for printing. Today's powerful microprocessors enable embedded controllers to be used, rather than external servers — equipment vendors typically offer both options. Embedded controllers are perfect for cluster systems: They reduce equipment cost while offering the convenience and functionality of a full-blown operating system typically found on a dedicated server.

In centralized printing operations, incoming jobs are rarely sent straight to the printers. They typically go to a holding queue so that an operator can prioritize jobs and ensure the proper paper stock is loaded. A cluster-printing system provides a common control point for one person to conveniently operate a bank of printers.


The three primary suppliers of cluster-printing technology are AHT (El Segundo, CA), Electronics for Imaging (EFI) (New York City) and T/R Systems (Norcross, GA). These companies' products are sold by various printing-equipment manufacturers and distributors, sometimes under different product names (see chart, opposite).


AHT develops print servers and software for driving a wide range of equipment. Vendors such as Canon (Lake Success, NY) and Konica (Glen Cove, NY) sell AHT products. AHT also sells products directly to end users.

AHT OneRIP is a PC-based server that drives black-and-white copier/printers, full-color copiers and wide-format printers. OneRIP is targeted at both commercial and corporate print-on-demand environments, where it provides a common interface for all devices, consolidates print-server requirements and enhances device functionality.

OneRIP supports up to 10 monochrome digital printers, two full-color copier/printers or four large-format inkjet printers. Features include:

  • Cluster printing

  • Support for popular networks, platforms (PC, Macintosh and UNIX) and file types

  • Scanback for transforming a digital copier into a network scanner

  • Electronic collation, priority printing, concurrent RIP and print, continuous print, and intelligent scheduling

  • Variable data

  • Layout tools for color printing.

Unify is AHT's latest server offering. It supports the same elements as AHT's previous server products, while extending their functionality. Unify connects to printers over standard networks and includes multiple-copy splitting, job splitting, load balancing, job recovery, and automatic separation of color and black-and-white pages. With the Unify Konica server, for example, monochrome pages could automatically be routed to a Konica 7075 or FORCE 75, and color pages sent to a Konica 7920/7915 color machine. The system prints an insert page showing where the color pages should be merged into the black-and-white document.


EFI is the leading supplier of color-print servers, including Fiery, EDOX and Splash products. The company also provides embedded controllers and servers for black-and-white copier/printers. EFI products are bought by printer manufacturers and bundled with their respective products. Last year, EFI launched Velocity, a suite of software modules available from EFI Fiery distributors.

Velocity consists of four modules: Velocity Balance, Velocity Build, Velocity Scan and Velocity Estimate. Velocity Balance is the core module of Velocity — it provides print clustering, load balancing, job management and error recovery. It can manage up to 12 Fiery- or EDOX-attached printers, and supports both monochrome and color machines. Other features include:

  • Job splitting — long documents can be split across multiple engines, or long runs distributed as sets across printers in the cluster

  • Automatic splitting of black-and-white and color pages from documents

  • Job routing to the most appropriate devices in the cluster

  • Automatic redirecting of jobs when engines are unavailable

  • Job scheduling

  • Queue management.

The feature that allows black-and-white and color pages to be split out of a document and directed to the appropriate printer should appeal to anyone who recalls the laborious and error-prone task of doing this manually. EFI offers three different workflow options:

  • Cover pages can be printed to identify the location of each insertion

  • Barcodes can be printed for reading and interpretation by a Duplo inserter for automatically pulling inserts

  • Color pages can be loaded into a cover-insertion tray on a black-and-white machine and pulled on-the-fly using set-up information downloaded from Velocity.

Velocity Build complements Velocity Balance by providing document preparation and preview. Features include: job editing, merging, page deletion and insertion, job preview prior to printing, document imposition, PDF editing tools and imposition through hot folders for automatically processing jobs.

Velocity Scan supports scanning of black-and-white and color documents from TWAIN-compatible scanners. Other features include: simplex or duplex scanning, de-skewing and de-speckling, automatic scanning into PDF format and direct scanning to Velocity Balance for editing and printing.

Velocity Estimate is a job costing and estimating module that prices individual jobs and performs trend analysis. Other features include: estimates for job setup, supplies, finishing, overhead, profit margin and per-impression maintenance charges; Web interface; and export to databases.


T/R Systems, which first introduced the MicroPress in 1995, has played a major role in popularizing cluster printing. The MicroPress is a server-based solution that is also sold by IKON (Malvern, PA); in addition, Minolta (Ramsey, NJ), HiKIS (Simi Valley, CA), Ricoh (West Caldwell, NJ) and Toshiba (Irvine, CA) offer private-label versions to complement their copier/printers.

MicroPress servers can drive clusters of two to 12 black-and-white copier/printers, color copiers or wide-format inkjet printers. Since jobs are RIPed at the MicroPress server, some printers are connected to the central server with T/R Systems' PrintLink, an external controller that provides a high-speed video interface between the server and the printer. Newer devices are connected via standard network controllers.

MicroPress features include:

  • Ability to edit and preview files after they have been rasterized (TrueEdit)

  • Access (through e-PSM) from standard Web browsers to many of the MicroPress post-RIP document-management features

  • Integration of MicroPress production data with third-party billing, authentication and tracking applications (e-Prove)

  • Ability to convert rasterized documents into standard file formats such as HTML and Microsoft Word (OCR and MicroTiff)

  • Archive to PDF automatically compresses and archives jobs, which can later be retrieved and reprinted.

T/R Systems currently offers three different server products collectively called the MicroPress X Series. The MicroPress SX supports up to four devices simultaneously but does not automatically split jobs across devices. Job parsing and error recovery can be added as an option. The MicroPress DX provides true cluster printing on two to four black-and-white and/or color devices, and offers extensive makeready features. The MicroPress MX supports clusters of up to 12 devices and provides real-time data recovery.

T/R Systems offers a software product called M@estro for network device administration, document distribution and workflow management. Digital Store Front is a turnkey server for Web-based job submission and workflow automation.

M@estro software allows users to locate and manage networked print devices, and tracks device status and utilization. It also routes jobs to appropriate destinations through routing queues that contain instructions on how to distribute documents to destinations such as network folders, FTP sites, e-mail addresses and printers. M@estro's workflow functionality allows organizations to create rules and procedures that control document processing. M@estro is designed to increase productivity and reduce overall printing costs. Xerox offers a version of M@estro that supports clustering of the Document Centre 480ST and the DocuColor 12. Support for the Xerox DocuTech and DocuColor 2000 series is planned.

Shorter runs, but more jobs sidebar

In addition to the proliferation of network-ready, digital toner-based devices, there's another reason some printers are evaluating the merits of cluster-printing products: the trend toward shorter runs but more jobs.

While it may seem contradictory, many printers are reporting higher print volumes but shorter run lengths. The only possible explanation is that there are simply more individual jobs. Not only are there more jobs, but turnaround requirements for them are shrinking.

PIA (Alexandria, VA) estimates that in 2000, about 15 percent of all printing was delivered within a day, 18 percent delivered in five days and 13 percent in five to eight days. PIA expects that by the end of this decade, as much as 30 percent of all printing could be turned around in one day or faster. Although volume levels may stay the same, if you have to run more jobs to achieve it, you're going to need more labor. Thus, centralized management systems capable of handling the added burden placed on the print shop will play an increasingly important role — another advantage for the cluster-printing concept.