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SMART
DIGITAL
Glossary I J K L M N O P
I
imagesetter
A digital film recorder that can handle both text and images. Imagesetters commonly
output film, resin-coated photographic paper, and paper or polyester printing
plate materials. A new class of devices called platesetters includes devices
which can also image on paper, polyester, or metal plate materials.
imposition
The process of placing the pages of a document in the correct orientation on
a press sheet to ensure that after the sheet is folded and trimmed that the pages
will fall in the proper page order.
impression cylinder
The cylinder of a printing press that brings the sheet of paper into contact
with the blanket cylinder.
impressions per minute (ipm) or hour (iph)
The total number of printed sides that an electronic printer or offset press
can print in one minute or one hour. There is potential confusion between this
and pages per minute. For example, a printer that prints 50 single-sided pages
per minute, is a 50 ppm printer. If it prints duplex at the same speed, it is
considered a 100 ipm printer. The paper doesn’t move any faster, but it
has twice as many images applied to it in the same amount of time. See pages
per minute.
inkjet
A printer that creates images by spraying droplets of ink from either a single
print head moving across the surface of the paper, or from multiple print heads
arranged in a line across the width of the paper. Continuous inkjet sprays a
continuous stream which is redirected to form the image area. Drop on demand
sends a droplet only when needed.
input resolution
The spatial resolution of a scanner which is commonly measured in dots or pixels
per inch.
integrated services digital network (ISDN)
A high-speed digital network capable of moving large computer files at speeds
of a megabyte a minute or higher.
intelligent printer data stream (IPDS)
A data stream used in some IBM printers consisting of structured fields to control
the printer.
J
just-in-time printing
Digitally stored jobs that reside in an archive and which can be ordered and
re-printed at short notice at the request of the customer.
K
kilobyte (KB, K)
1,024 bytes of digital data.
L
large-format (system)
A system that can handle substrates 24" or wider.
laser
A focused beam of light that is used in many imaging systems. Laser is an acronym
that stands for Light Amplification by Stimulated Emission of Radiation.
laser printer
A printer which creates a beam of light that travels through lenses and is guided
to a rotating multi-faceted mirror that aims the beam onto a drum, imaging back
and forth as the drum and mirror rotate.
latent image
A latent image is an image that is present but not yet visible. For example,
a latent image exists on exposed film that hasn’t been processed. In electrophotography,
the latent image is composed of static charge present on the photoconductive
drum. The image only becomes visible after toner is applied.
light emitting diode (LED)
A solid-state, light-emitting device that is used in some imaging systems.
line art
A picture such as a pen and ink drawing that contains only black & white
lines, dots, or solids. In order to digitize a line art original, a scanner only
needs to register whether a pixel is turned on (black) or off (white). The term
line art is used to describe drawings containing flat colors without tonal variation.
Compare with contone.
lines per inch (lpi)
A measure of the fineness of a halftone screen ruling. The higher the number,
the finer the screen ruling. For example, 60 lpi is a coarse screen ruling used
for some 300 dot per inch laser printers. Some high-quality poster work is printed
with a 200 lpi screen ruling.
line printer
A device that prints an entire line at a time.
local area network (LAN)
Within a limited geographic area (i.e., an office or a building), a combination
of computer hardware and software that interconnects numerous computers and peripherals
to provide printing services and communication with and access to shared data.
See WAN.
M
magnetic image character recognition (MICR)
A system using ink or toner with a high iron oxide content that can be magnetized.
MICR printing can be read, for example, by automated check processing machines
in banks.
magnetography
An imaging process that uses a metal drum to transfer a magnetically recorded
image onto paper.
magneto optical (MO)
Storage technology which combines an optical laser with a magnetic field to read
and write data on a coated glass or plastic disk. MO disks are available in two
formats: rewritable optical and Write Once/Read Many (WORM) format. Typically,
a cartridge has a 1.3 GB capacity with access times as low as 25 ms, significantly
slower than the fastest hard disks, but on par with other removable media.
make-ready
The process of preparing a printing device to output which includes plate making
and mounting, loading paper and ink, and the adjustment of registration and color.
marking
A method used by printers to put dots of ink or toner onto paper. A print engine
is sometimes called a marking engine.
matte
A coated sheet of paper which has a flat surface or finish and does not reflect
a lot of light. See gloss.
megabyte (MB)
1,024 KB of digital data.
mean time between failures (MTBF)
The average period of operation before mechanical or software breakdown.
metacode
A Xerox-developed data format used to describe printed output for Xerox printers.
modem
A device through which computer data can be transmitted over telephone lines.
moisture content
The amount of moisture in a printed sheet, which may range from 4% to 8%. Paper
may emit or absorb moisture, and this can affect paper curl, static build-up
and runnability in copier and printer papers.
mopier
An acronym for “multiple original printers” coined by Hewlett-Packard
to describe a printer capable of printing “multiple original copies,” a
document is sent to the mopier’s hard drive where it is stored for reprint.
multifunction Peripheral (MFP)
A machine that combines several capabilities, such as printing, scanning, copying,
or faxing.
N
network
A system of cables which interlinks a number of devices to allow communication
between workstations and printers. See local area network and wide area network.
newsprint
A grade of paper composed primarily of groundwood pulp.
O
offset lithography
A printing process which uses printing plates and blankets to transfer ink to
the paper. The “offset” occurs when the ink is transferred first
from the plate cylinder to the blanket cylinder and finally to the paper.
on demand
See print on demand.
one-to-one marketing
Marketing to one customer at a time using personalized messages (variable data).
opacity
A measure of the ability of light to pass through a sheet of paper. Opacity is
particularly important for sheets that are printed on both sides.
open prepress interface (OPI)
A prepress standard developed by Aldus (now part of Adobe) and other prepress
vendors for facilitating data exchange between desktop publishing and prepress
systems.
P
page description language (PDL)
A computer language for describing how text and graphics should be placed on
a page for display or printing. Examples: Adobe PostScript and Hewlett-Packard
Printer Command Language (PCL).
page independence
An electronic document is page independent if the pages are accessible as
individual units, for either viewing or printing. A good example of page dependence
versus page independence comes from the PostScript world. A document written
in PostScript code is page dependent. To print a single page, you must process
the entire document. An Adobe Acrobat PDF file, on the other hand, is page independent.
You may view and print pages as individual units. Page independence is important
for print on demand because it gives users increased flexibility to merge portions
of existing documents, impose and collate them electronically. Without page independence,
the process is much more cumbersome for the RIP.
pages per inch (ppi)
A measure of the number of pages per inch. Commonly utilized in the the book
publishing industry.
pages per minute (ppm)
A measure of the print speed of a printer.
page printer
A printer that has to process an entire page before it can begin to print the
page; for example, a printer that creates a latent image on a photoconductor.
paper sizes
Certain paper grades have standard sizes. (See paper grade sheet size.) For
the smallest sizes (A3 and A4), these sheets are close, but not quite equal
to U.S.
standard letter (8.5" x 11") and ledger (11" x 17") sheet
sizes.
personalized print on demand
The ability to vary all or some of the content of a document to customize it
for a specific individual or targeted group by linking the print on demand system
to a database.
paper grade sheet size
Bond, writing, xerographic: 17" x 22"
Cover: 20" x 26"
Index/bristol: 25.5" x 30.5"
Book/offset/coated/text: 25" x 38"
Petrabyte
1,024 terabytes of digital data
photoconductor
A metallic substance, used in electrophotographic printers, that conducts and
retains electrical charges until they are exposed to light.
pixel
The smallest unit of a digitized picture (i.e., a scan or digital illustration).
Pixel is a contraction of the words “picture element”. A scan’s
spatial resolution is usually measured in pixels or dots per inch.
platesetter
A digital recorder that can image on paper, polyester, or metal plate materials.
See imagesetter.
plateless imaging
A printing process, like inkjet or thermal transfer, in which pigment is applied
directly to the substrate without an intermediary printing plate.
platen
The glass bed of an analog copier, digital copier, or digital duplicator. Hard
copy originals are placed on the platen as part of the process of being reproduced.
porosity
The amount of air that will pass through a sheet of paper. (Porosity is an
important factor in devices that use vacuum feeders to move paper.)
portable document format (PDF)
A file format that was developed by Adobe Systems for their Acrobat product
line. A PDF file can be viewed and printed with a viewer that Adobe provides
free of charge. This makes it possible to create files that can be read by
a wide number of computer users on different computer platforms. Acrobat PDF
will very likely play an important role in print on demand. Adobe has announced
a RIP architecture that will use the page independence of PDF to accelerate
RIPping and to ease processing of individual pages.
post-consumer content
Post-consumer content refers to paper fibers recovered from papers that have
already been used (i.e., written, printed on) and then recycled. Many recycled
papers list the amount of post-consumer fibers that are used in the paper.
Post-consumer fiber stands in contrast to industrial waste fiber (pre-consumer)
which is recycled directly at the mill.
post-processing device
A device for stacking, stapling, stitching, cutting or inserting, that can
be used either on-line or off-line with a printer to produce finished documents.
postscript
A page description language developed by Adobe Systems that has become the
de facto standard in desktop publishing, design, and graphic arts applications.
pre-processing device
A device such as a roll or a high-capacity cut-sheet feeder that increases
the paper capacity of a high-speed printing system.
pre-rasterized images
Pages that have been translated into a raster by a RIP and are able to be stored
for later output.
primary colors
The primaries are pure colors that when mixed produce many other colors. There
are two types of color mixing: additive (light) or subtractive (pigment). The
colors red, green, and blue (RGB) are additive because increasing the amount
of these colors increases the brightness of the image, ultimately resulting
in white if 100% of each color is present. The colors cyan, magenta, and yellow
are subtractive because increasing their amount subtracts brightness from the
reproduction. In theory, 100% of cyan, magenta, and yellow should produce black.
In practice with actual pigments, the result is a muddy brown. This is one
reason why black is needed for color printing.
print buyer
The person responsible for selecting and contracting the services of a print
provider.
print on demand (POD)
An electronic printing process that delivers exactly and only what the customer
wants, when the customer wants it, and at the place where it is needed.
print provider
The person or company that handles the manufacture of printed materials for
the print buyer.
print server
A network server assigned to manage local or remote printers and printer queues.
The print server keeps track of print jobs, allows manipulation of print queues,
and sends print jobs to electronic printers.
printer command language (PCL)
A page description language developed by Hewlett-Packard. It is sometimes referred
to as HP PCL. Numerous versions of PCL exist, including PCL 5C (for color output).
pulse modulation
An image enhancement technique which varies the power supplied to the laser
or LED to alter the size of the spots being recorded.
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