Laser Printers
An older technology than inkjet, laser printers are another popular
alternative to legacy impact printing. Laser printers are known for
their high volume output and low cost-per-page. Laser printers are often
deployed in enterprises as a workgroup or departmental print center,
where performance, durability, and output requirements are a
constant. Because laser printers service these needs so readily (and at
a reasonable cost-per-page), the technology is widely regarded as the
workhorse of enterprise printing.
Laser printers share much of the same (or similar) technologies as
photocopiers. Mechanized rollers and gears pull a sheet of paper from a
paper tray and through a charge roller, which
infuses the paper with an electrostatic charge. The paper then passes
through a printing drum, which is itself inversely charged and scanned
by a laser that emits the print contents across the drum, discharging
the drum at points corresponding to text and image points. The laser
receives the print information from the laser printer's microprocessor,
which in some cases can be a powerful RISC
(Reduced Instruction Set Computer) architecture processor used for
complex image rendering of print jobs. The processor
rasterizes (or creates bitmap images from vector
primitives and/or typographical/layout expressions) the print job and
directs the laser to recreate a reproduction onto the drum. Then, as the
paper passes through the drum, the charge of the paper reacts with the
inversely charged drum. Toner (special powdered
ink) is sprinkled on the drum and is pulled off of the drum as the paper
passes through. Finally, the paper is passed through fusing
rollers, which heat the paper and melts the toner (which
would otherwise slide off the page as it exits the printer) onto the
paper. The paper exits the printer literally hot off the
press.
Color Laser Printers
Color laser printers are an emerging technology created by printer
manufacturers whose aim is to collect the features of laser and
inkjet technology into a multi-purpose printer package. The
technology is based on traditional monochrome laser printing, but uses
additional technologies to create color images and documents. Instead
of using black toner only, color laser printers use a CMYK toner
combination. The print drum either rotates each color and lays the
toner down one color at a time, or lays all four colors down onto a
plate and then passes the paper through the drum, transferring the
complete image onto the paper. Color laser printers also employ
fuser oil along with the heated fusing rolls,
which further bonds the color toner to the paper and can give varying
degrees of gloss to the image finish.
Because of its increased features, color laser printers are
typically twice (or several times) as expensive as a monochrome laser
printer. In calculating the total cost of ownership with regards to
printing resources, some administrators may wish to separate
monochrome (text) and color (image) functionality to a dedicated
monochrome laser printer and a dedicated inkjet printer,
respectively.
Laser Consumables
Depending on the type of laser printer deployed, consumable costs
usually are fixed and scale evenly with increased usage or print job
volume over time. Toner comes in cartridges that are usually replaced
outright; however, some models come with refillable cartridges. Color
laser printers require one toner cartridge for each of the four
colors. Additionally, color laser printers require fuser oils to bond
toner onto paper and waste toner bottles to capture toner
spillover. These added supplies raise the consumables cost of color
laser printers; however, it is worth noting that such consumables, on
average, last about 6000 pages, which is much greater than comparable
inkjet or impact consumable lifespans. Paper type is less of an
issue in laser printers, which means bulk purchases of regular
xerographic or photocopy paper is acceptable for most print jobs;
however, if you plan to print high-quality images, you should opt for
glossy paper for a professional finish.
