Configuring Printer Parameter Overrides

This section contains details on setting up CCLAS printers on a CUPS server.

Printing from a web-based application to a network printer requires that printers and print spools can be accessed and managed robustly. Also, based on the type of report produced by CCLAS, it is a requirement that different printer parameters are set for printing the report.

Note: IPP enabled printers do not need to use CUPS Printer Management. They can be set up to print direct or using best practice user servers with IPP functionality such as Windows Server 2003 or 2008.
• To add a printer in CCLAS, refer to Maintaining CCLAS Devices.
• To access CUPS through the terminal using a terminal emulator application (such as PuTTY) and to use the terminal access to restart the server or adjust the configuration file, refer to the activity to Set up a CUPS Server in Linux.

When setting up printers, the IPP details for each printer are typically provided by the administrator who looks after the CUPS server. The Printers tab in the CUPS web interface displays the details, which is displayed as the device Uniform Resource Identifier (URI), for example:

ipp://<host>:<port>/printers/<printer>

Terminology

The following table introduces terminology needed to understand the CCLAS batch processing mechanisms for printing:

Term	Definition
CUPS	Common UNIX Printing System TM. See CUPS E8 document that discusses the operations for Managing CUPS CCLAS Printers.
IPP	The Internet Printing Protocol (IPP) provides a standard network protocol for remote printing as well as for managing print jobs.
PPD file	The PPD file is required by CUPS if the Printer Model is not available. The file serves as a driver for a PostScript printer; describes the font, paper sizes, DPI resolution, memory configuration, and other features and capabilities supported by the printer. PPD files may also contain PostScript code that can be referenced during a print job. This code includes commands that invoke specific PostScript printing features.

Term

Definition

CUPS

Common UNIX Printing System TM. See CUPS E8 document that discusses the operations for Managing CUPS CCLAS Printers.

IPP

The Internet Printing Protocol (IPP) provides a standard network protocol for remote printing as well as for managing print jobs.

PPD file

The PPD file is required by CUPS if the Printer Model is not available. The file serves as a driver for a PostScript printer; describes the font, paper sizes, DPI resolution, memory configuration, and other features and capabilities supported by the printer.

PPD files may also contain PostScript code that can be referenced during a print job. This code includes commands that invoke specific PostScript printing features.

Introduction

The Common UNIX Printing System TM (CUPS) is the software you use to print from applications like the web browser you are using to read this page. It converts the page descriptions produced by your application (put a paragraph here, draw a line there, and so forth) into something your printer can understand and then sends the information to the printer for printing.

Now, since every printer manufacturer does things differently, printing can be very complicated. CUPS does its best to hide this from you and your application so that you can concentrate on printing and less on how to print. Generally, the only time you need to know anything about your printer is when you use it for the first time, and even then CUPS can often figure things out on its own.

CCLAS is designed to use Internet Printing Protocol (IPP) which requires an IPP capable print server. A customer can deploy CUPS (Common UNIX Print Server) software to facilitate IPP printing. This requires customer printers to support postscript.

Direct IPP Connection

A direct printing connection using the Internet Printing Protocol (IPP) allows a client to submit one or more print jobs to the printer or print server and perform tasks such as querying the status of a printer, obtaining the status of print jobs, or cancelling individual print jobs. Like all IP-based protocols, IPP can run locally or over the Internet.

When a direct IPP connection is used to interrogate and override the properties of a printer, whilst various properties can be overridden, often there are no proper queuing capabilities, and the a printer can return with a busy exception.

IPP + CUPS Printing Arrangement

CUPS (Common UNIX Printing System) is a printing system for Unix-like computer operating systems which allows a computer to act as a print server, freely available under the Apache License.

An IPP + CUPS printing arrangement allows network printers to be controlled and have their properties overridden. For this, a CCLAS printer device can have printer parameters to override default printer properties.

A computer running CUPS is a host that can auto-detect network printers, accept print jobs from client computers, process them, and send them to the appropriate printer. CUPS manages print jobs and queues, provides network printing using the standard Internet Printing Protocol (IPP), and offers support for a very large range of printers, from dot-matrix to laser and many in-between.

System administrators configure the device drivers which CUPS supplies by editing text files in Adobe's PostScript Printer Description (PPD) format. There are a number of user interfaces for different platforms that can configure CUPS, although it has its own in-built web-based configuration and administration tool.