An Overview of Digital Printing Systems - Control of Color Imaging Systems: Analysis and Design - page 9

Printer 2

Control

Printer 1

FIGURE 1.6 Schematic side view of a parallel printing system. (US Patent Application
20060197966, Gray balance for a printing system of multiple marking engines, Sept. 7, 2006.)

act as one. As such, multiple printers can be employed in the printing of a single print
job. More than one print job can be in the course of printing at any single time
instant.
The printers can be fed with paper from a variety of feeder modules loaded with
a variety of paper types. A

finishing capabilities may receive
printed sheets from any of the printers. Job output trays may include one or more
special trays for multiple job collections. The

finisher with different

finisher may also include a purge tray
for diverting sheets in order to maintain the integrity of the job.
The media handling system may include highways that extend from the feeder
module to the

finisher and pathways to transport the print media between the
downstream media highways and selected ones of the printers. For example, when
printing a two-page document, page one may be printed by printer one and page two
by printer two, where pages one and two may be formed on opposite sides of the
same sheet (duplex) or on separate sheets (simplex). Thereafter, these sheets are sent
to finisher in the correct order. The highways and = or pathways may include inverters,
reverters, interposers, bypass pathways, and the like, as known in the existing art,
to direct the print substrate between the highway and a selected printer or between
two printers.
One of the printers may be designated as a reference or master printer with the
remaining printer considered a slave. The master is linked by a network of paper
pathways to sensors in the printing system. Printers may include electrophotographic
printers, ink-jet printers, including solid ink printers, thermal head printers that are
used in conjunction with heat-sensitive paper, and other devices capable of marking
an image on a substrate. Thus many different printing technologies can be incorp-
orated within a TIPP system with a complex network of media paths so that all
engines work as one, thus providing the user with the productivity and speed of a
multi-engine printer. A tandem Xerox Nuvera 288 digital perfecting system is a
twin-engine monochrome press that uses a technology that keeps one engine running
at full speed, even if the other stops.
At the Drupa 2008 trade show, Xerox demonstrated the Xerox ConceptColor
220 (Figure 1.7) with its tightly integrated serial printing (TISP) architecture. It takes