High-quality color inkjet office printers - design of HP DeskJet 1200C and HP DeskJet 1200C/PS printers - Technical

Hewlett-Packard Journal, Feb, 1994 by Douglas R. Watson, Hatem E. Mostafa

The HP Deskjet 1200C and 1200C/PS printers are a new class of HP Deskjet printers for office applications. They offer black and color printing, fast print speeds, scalable typefaces, expandable memory, networking options, PCL 5 and PostScript[TM] languages, and HP LaserJet printer compatibility.

When HP introduced the Paintjet(1) and Deskjet(2) printers in 1987 and 1988, customer expectations of personal printers were changed. Customers learned to expect quiet operation, exceptional color, and low cost with good throughput in an affordable personal printer.

Together, these two printers provided a full-featured printing solution. However, each printer had limitations that kept it from being the single desktop product for all printing needs. The Deskjet delivered high-quality plain paper text with industry-leading speed in an affordable printer, but there were still opportunities to improve print quality when printing on a variety of papers including the newly appearing recycled papers. The Paintjet delivered high-quality color at a low price but lacked plain paper capability and the 300-dpi text that the HP LaserJet printer family had made a minimum requirement for general-purpose office printers. The Deskjet 500C printer(3) introduced in August 1991 added plain paper color capability to the product line. The Deskjet 500C and the two-pen Deskjet 550C continued the march of inkjet technology toward the mainstream office.

In May 1992, the HP Paintjet XL300 printer delivered the first true laser--quality color capability for the mainstream office. This product offered exceptional print quality. Its price and size positioned it as a superior shared or networked solution.

After assessing customer needs, product development teams were formed for the new HP Deskjet 1200C printer and several new print cartridges. The objective was to deliver a high-performance personal and office printer combining all of the best features of the existing products while extending the technology in the areas of throughput, quality, and cost. During the development cycle the opportunity to apply the print cartridges under development to the large-format market became apparent. A team was formed to adapt the cartridges to the Design Jet 650C large-format drafting plotter to meet those needs. The R&D teams accepted the challenge of incorporating all of these goals in one program, delivering the benefits of this new technology in two products with seven new but highly leveraged print cartridges.

Customer-Driven Development

The design objectives for the Deskjet 1200C were set with the overriding goal of moving color into the mainstream office market using inkjet technology without sacrificing the features to which customers had become accustomed in laser printers. This resulted in the following specific objectives:

* Laser-speed text printing--more than four pages per minute (seven pages per minute was ultimately achieved, and six is specified)

* Industry-leading color quality on plain paper

* Fast color throughput-one to two minutes per page

* Color cost per copy better than any technology at any use rate

* Desktop form factor--less than 20 inches wide

* Improved transparency and glossy paper performance

* Product cost less than or equal to laser printers of equivalent capability

* Ink supply sensing for network or batch print jobs.

In addition to being asked to deliver the first truly mare stream color printer for the office, the Deskjet 1200C and print cartridge program team was also charged with delivering the solution to the marketplace in less than two years, a record time for such an advanced product/print cartridge system. To meet this aggressive time-to-market goal, the printer and print cartridge teams had to make fundamental changes in the processes by which such print systems are developed.

To translate the list of objectives into designs, teams were formed to choose the best implementation solutions without regard to whether a particular solution was implemented in the product, print cartridge, or media. These teams, called seam teams, were composed entirely of and led by engineers. At an extraordinary rate, they developed technical solutions to the objectives that offered the highest quality and the lowest cost. The result is a well-tuned high-performance printer that delivers all of the major desires identified by customers.

On the printer development team, the traditional roles of design, manufacturing, and reliability engineering were all combined into a single role: that of the development engineer. The development engineers became solely responsible for the design, manufacturability, assemblability, testability, and reliability of their parts. This structure greatly empowered the engineering team and allowed rapid, global optimization of major design and architectural decisions. New rapid prototyping techniques were developed to improve both the accuracy and the timeliness of early prototype units. In addition, new aggressive tooling strategies shaved months from the traditional tooling cycle times. Finally, early supplier involvement, including early interaction of HP production people with all the design aspects of the product ensured rapid convergence of all manufacturing issues. As a result of this streamlined development process, the laboratory phase of the development cycle for the HP Deskjet 1200C printer was completed in the shortest time in the division's history.