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In addition to the hardware that actually does the printing, Windows
computers have a number of other components devoted to their print architecture. The main components of a shared printer solution in the Windows environment are as follows:
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Print device In Windows, the term print device
refers to the actual hardware that produces the hard copy output from a
print job. Windows enables you to share a print device that is
connected to any computer on the network using a universal serial bus
(USB), IEEE 1394 (FireWire), or other port; or connected directly to the
network. -
Printer Although the term is commonly used to refer to the hardware, the term printer,
in Windows, actually refers to the logical representation of a print
device that appears in the operating system and on the network. You can
create a printer in Windows without there being an actual print device
connected to the computer or the network, and it will appear in the
Devices And Printers Control panel just as if the hardware were present.
A Windows printer tells the system which port, or interface, it must
use to connect to the print device, as well as the printer driver the
system must use to process its print jobs and communicate with the print
device. -
Print server A print server
is the component responsible for holding print jobs in a queue and
sending them, one at a time, to the print device. A print server can be a
dedicated hardware component that connects the print device to the
network, but more often, one (or more) of the computers on the network
functions as the print server. In Windows printing, you can create a
single print server that receives jobs from all the clients on the
network and feeds them to the print device, or each client can function
as its own print server, sending jobs directly to the print device. -
Printer driver The printer driver
is the software component that receives output from applications
generating print jobs and converts it into a data stream using a page description language (PDL),
which consists of commands that the print device understands. Windows
printer drivers generate print jobs using an interim format called Enhanced Metafile (EMF).
The EMF data is then converted into a device-specific RAW format,
either by the client or the print server, depending on the printer
configuration. The print server then stores the RAW data in the print
queue until the print device is ready to accept it.
Note
Administrators can distribute these components
around the network in various ways, to accommodate the printing
strategy they want to create. Every computer that generates print jobs
must have a printer and a printer driver, but you can locate print
servers and print devices anywhere on the network.
The process by which a computer prints a document includes the following steps and is shown in Figure 1:
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A user working with an application activates its print function,
selects one of the printers installed on the computer, and configures
application-related settings, such as what pages of the document to
print. -
The application calls the printer driver associated with the selected
printer, enabling the user to configure printer-related settings, such
as which paper tray to use. -
The printer driver converts the application’s print output into XML Paper Specification (XPS) or EMF commands and data, which it sends to the print server. -
The print server stores the job in a print queue called a spooler, in which it waits until the print device is ready to accept the job. -
When the print device is ready, the print server reads the job from the spooler, converts it from EMF to a Printer Control Language (PCL) format, if necessary, and sends it to the print device using the appropriate port. -
The print device receives the job from the print server, processes the commands and data, and generates the hard copy output.
Designing a Network Printing Solution
The printing architecture on a small business network is usually not
complicated. Small businesses typically have, at most, two or three
print devices, but administrators still have to make design decisions such as the following:
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How will the print devices connect to the network? -
Which computer(s) should function as print servers? -
Who has access to the print devices and when? -
Who is responsible for daily printer maintenance?
Before you can share a print device with your Windows SBS 2011
network, you must connect the hardware to one of the computers on the
network or connect it directly to the network. Most of the print devices
on the market today connect to a computer using a USB or IEEE 1394
port, and many also have an integrated network interface adapter, which
enables you to connect the device directly to your Ethernet or wireless
network. Older print devices might connect to a computer using a
parallel or serial port, and, in some cases, you can purchase a network
interface adapter as an expansion card that plugs into the printer.
Finally, you can purchase an external print server device that connects
directly to the network and has a port for connecting the print device.
The type of print device connection you use should depend on your
network design, the layout of your office, and, as always, your budget.
When you connect a print device to a computer, as shown in Figure 2,
that computer functions as a print server, receiving jobs from other
computers on the network and feeding them to the print device. Any
Windows computer, whether server or workstation, can function as a print
server. However, if your users do a lot of printing, the print server
functions can impose a significant burden on a workstation that does not
have much more than the minimum recommended Windows hardware to support
them. A constantly running printer can also be an annoyance to a user
trying to accomplish other tasks on the workstation.
If at all possible, connecting the print
devices to server computers is preferable to workstation connections
unless the servers are in a location that would be inconvenient for
users having to retrieve their printed documents. For example, if you
plan to locate your servers in a locked data center or server closet, it
would not be practical to locate your print devices there as well.
The best solution,
by far, is to connect your print devices directly to the network. This
solution enables you to locate your print devices anywhere a network
connection is available. You can also designate any computer on the
network as a print server, which enables you to use your server
computers for their intended purpose, no matter where they are located,
as shown in Figure 3.
It is also possible for each computer to function as its own print
server, sending jobs directly to the print device, as shown in Figure 4. The only drawback to network–attached print devices is that units with network adapters tend to be more expensive than those without them.
The first deciding factor in selecting a computer to function as a
print server is the type of print device connections you plan to use. As
mentioned earlier, if you connect a print device directly to a
computer, that computer must function as the print server.
Network-attached printers provide greater flexibility.
In addition to the type of connections you plan to use, however, you
should also base your selection of a print server on the following
factors:
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Print volume The
more printing your users do, the greater the burden on the print server.
Large numbers of documents use more print server resources than small
numbers, lengthy documents use more resources than brief ones, and
graphical documents use more than plain text. -
Print rendering
When a print server is running Windows Server 2008 R2 or Windows 7, you
can specify whether the client or the print server should render the
print jobs. Client-side rendering (CSR) reduces the burden on the print server. -
Computer resources Print volume and CSR
both affect the resources used by print server functions. For example, a
workstation with the minimum recommended system requirements can
function adequately as a print server, but its functionality as a
workstation might be compromised.
Controlling Access to Print Devices
In many cases, administrators grant users unrestricted access to the
print devices on the network. However, you might want to regulate access
to color print devices, or other units with expensive consumables such
as letterhead paper. Windows printers have their own permission system, which functions similar to NTFS and share permissions.
You can specify which users can send jobs to a printer and also control
access based on other factors, such as the time of day and the user’s
priority.
Tip
Print devices are some of the few network hardware components that require maintenance on almost a daily basis. Part of your printing solution
should include a decision as to who is responsible for the print
devices’ regular maintenance, including tasks such as loading media,
clearing paper jams, and replacing toner or ink cartridges. These are
thankless tasks that many people try to avoid, so it is important to
delegate them decisively. Otherwise, you might find a huge backlog of
print jobs left in the queue because the print device is out of paper or
toner, and no one has bothered to replenish them.
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