Printer Study Notes
What is printer?
Personal computer printers can be distinguished as impact or non-impact printers.
Early impact printers worked something like an automatic typewriter, with a key striking an inked impression on paper for each printed character.
The dot-matrix printer was a popular low-cost personal computer printer. It's an impact printer that strikes the paper a line at a time. The best-known non-impact printers are the inkjet printer, of which several makes of low-cost color printers are an example, and the laser printer.
The inkjet sprays ink from an ink cartridge at very close range to the paper as it rolls by.
The laser printer uses a laser beam reflected from a mirror to attract ink (called toner) to selected paper areas as a sheet rolls over a drum.
Laser Jet Dot Matrix
The four printer qualities of most interest to most users are:
Printer I/O Interfaces:
The most common I/O interface for printers are described below.
In the context of the Internet and computing, parallel means more than one event happening at a time. It is usually contrasted with serial, meaning only one event happening at a time. In data transmission, the techniques of time division and space division are used, where time separates the transmission of individual bits of information sent serially and space (in multiple lines or paths) can be used to have multiple bits sent in parallel.
In the context of computer hardware and data transmission, serial connection, operation, and media usually indicate a simpler, slower operation (think of your serial mouse attachment). Parallel connection and operation (think of multiple characters being sent to your printer) indicates faster operation. This indication doesn't always hold since a serial medium (for example, fiber optic cable) can be much faster than a slower medium that carries multiple signals in parallel.
A conventional phone connection is generally thought of as a serial line since its usual transmission protocol is serial.
and their programs operate in a serial manner, with the computer reading a
program and performing its instructions one after the other. However, some of
today's computers have multiple processors that divide up the instructions and
perform them in parallel.
USB (Universal Serial Bus) is a plug-and-play interface between a computer and add-on devices (such as audio players, joysticks, keyboards, telephones, scanners, and printers). With USB, a new device can be added to your computer without having to add an adapter card or even having to turn the computer off. The USB peripheral bus standard was developed by Compaq, IBM, DEC, Intel, Microsoft, NEC, and Northern Telecom and the technology is available without charge for all computer and device vendors.
USB supports a data speed of 12 megabits per second. This speed will accommodate a wide range of devices, including MPEG video devices, data gloves, and digitizers. It is anticipated that USB will easily accommodate plug-in telephones that use ISDN and digital PBX.
Since October, 1996, the Windows operating systems have been equipped with USB drivers or special software designed to work with specific I/O device types. USB is integrated into Windows 98 and later versions. Today, most new computers and peripheral devices are equipped with USB.
FireWire is Apple Computer's version of a standard, IEEE 1394, High Performance Serial Bus, for connecting devices to your personal computer. FireWire provides a single plug-and-socket connection on which up to 63 devices can be attached with data transfer speeds up to 400 Mbps (megabits per second). The standard describes a serial bus or pathway between one or more peripheral devices and your computer's microprocessor. Many peripheral devices now come equipped to meet IEEE 1394.
Printers can also be attached with the help of infrared adapter. A simple diagram of a printer with an infrared adapter is shown below.
Printer languages are commands from the computer to the printer to tell the printer how to format the document being printed. These commands manage font size, graphics, compression of data sent to the printer, color, etc. The two most popular printer languages are Postscript and Printer Control Language.
Postscript is a printer language that uses English phrases and programmatic constructions to describe the appearance of a printed page to the printer. This printer language was developed by Adobe in 1985. It introduced new features such as outline fonts and vector graphics. Printers now come from the factory with or can be loaded with Postscript support. Postscript is not restricted to printers. It can be used with any device that creates an image using dots such as screen displays, slide recorders, and image setters.
PCL (Printer Command Language) is an escape code language used to send commands to the printer for printing documents. Escape code language is so-called because the escape key begins the command sequence followed by a series of code numbers. Hewlett Packard originally devised PCL for dot matrix and inkjet printers. Since its introduction, it has become an industry standard. Other manufacturers who sell HP clones have copied it. Some of these clones are very good, but there are small differences in the way they print a page compared to real HP printers. In 1984, the original HP Laserjet printer was introduced using PCL. PCL helped change the appearance of low-cost printer documents from poor to exceptional quality.
A font is a set of characters of a specific style and size within an overall typeface design. Printers use resident fonts and soft fonts to print documents. Resident fonts are built into the hardware of a printer. They are also called internal fonts or built-in fonts. All printers come with one or more resident fonts. Additional fonts can be added by inserting a font cartridge into the printer or installing soft fonts to the hard drive. Resident fonts cannot be erased unlike soft fonts. Soft fonts are installed onto the hard drive and then sent to the computer's memory when a document is printed that uses the particular soft font. Soft fonts can be purchased in stores or downloaded from the Internet.
There are two types of fonts used by the printer and screen display, bitmap fonts and outline fonts. Bitmap fonts are digital representations of fonts that are not scalable. This means they have a set size or a limited set of sizes. For example, if a document using a bitmap font sized to 24 point is sent to the printer and there is not a bitmap font of that size, the computer will try to guess the right size. This results in the text looking stretched-out or squashed. Jagged edges are also a problem with bitmap fonts. Outline fonts are mathematical descriptions of the font that are sent to the printer. The printer then rasterizes or converts them to the dots that are printed on the paper. Because they are mathematical, they are scalable. This means the size of the font can be changed without losing the sharpness or resolution of the printed text. TrueType and Type 1 fonts are outline fonts. Outline fonts are used with Postscript and PCL printer languages.
Cannot turn on printer
A blank page is ejected
Placement of the text or graphics is wrong
Paper is jammed in the printer
NOTE: To clear jammed paper from the printer, open the Access Cover and pull the paper towards you. If you cannot reach the jammed paper, turn the Panel Knob on the back of the printer, remove the panel, pull out the jammed paper, and then replace the panel. If you still cannot reach the paper, raise the Output Tray and remove the jammed paper from the Main Paper Tray.
To avoid paper jams, follow the suggestions below:
Printing a sample page
Print a sample page without being connected to a computer. This allows you to see that your printer is set up correctly.
Cleaning the print cartridges
Clean the print cartridges when lines or dots are missing from printed text or graphics.
NOTE: Do not clean the print cartridge unnecessarily because this wastes ink and shortens the life of the print cartridges.
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