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Printers and Printing. Types of Printers. Thermal Printers: a non-impact type of printer that uses heat to transfer images to paper. The print-head contains small resistive heating pins that melt a wax-based ink onto plain paper or burn dots onto paper coated especially for the process.
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Types of Printers • Thermal Printers: a non-impact type of printer that uses heat to transfer images to paper. The print-head contains small resistive heating pins that melt a wax-based ink onto plain paper or burn dots onto paper coated especially for the process. • Two types of thermal: direct thermal and thermal wax transfer • Direct thermal printers do not use ribbons. The printer prints the image by burning dots onto a specially coated paper as it passes over the heated print-head. (used by older fax machines) • Thermal wax transfer printers use a thermal transfer ribbon that contains a wax-based ink. Heat is applied to the ribbon by the thermal print-head that melts the ink to the paper. • Another type of printer used today is dye-sublimation. Instead of using ink, dye-sublimation printers use a transparent film roll with solid dyes embedded • Cyan • Magenta • Yellow • Black
Printer Types: Dot Matrix • “impact printers” • impact happens as the print-head fires pins or print wires at an ink ribbon, which contact the paper and leave a mark. • The print-head, (the assembly that contains the pins), moves left to right across the paper, one line at a time. This creates letters out of the circular dots of ink that impact the paper. (Can also move left to right and right to left) • Coils of wires form electromagnets that are called solenoids. These are energized, which causes the pins to strike forward • Use continuous feed paper How fast the dot matrix printer can operate is measured in characters per second (cps).
Color Inkjet Printer • Most common type of printer in home use today because of their low cost and moderate quality of print. • Print one column of dots in a line at a time. (typically faster than dot matrix printers) • Use liquid ink-filled cartridges that force out/spray ink particles at the page through tiny holes called nozzles. • The ink particles are forced out by applying pressure that is caused by electricity or an electrical charge. • Pressure inside the ink reservoir of the cartridge is less than the outside pressure. When the electricity is applied, then the pressure rises. This internal pressure causes small dots of ink to be forced out through the nozzles
Inkjet Printers (continued) • Two kinds of print-heads: • thermal-shock print-head: has a heating element that surrounds each nozzle. When it is heated by an electrical current, it causes the ink to expand. When the ink expands, it is forced out through the nozzle. • Piezoelectric print-heads (based on electrostatic charges.) When the deflection plates are electrically charged, the size and shape of the nozzle changes. This causes it to act like a pump. This pumping action forces ink through the nozzle to the paper. • When the paper leaves the printer, the ink is often still wet. Most inks dry in 10 to 15 seconds. • The quality of print for an inkjet printer is measured in dots per inch (dpi), and the print speed is measured in pages per minute (ppm).
Laser Printer • Most commonly used because of its high resolution, superior operation, and speed. (its internal operation is more complex) • Static electricity is used to temporarily hold small dry ink particles called toner to a statically charged image on an electro photographic drum. A laser beam is used to draw this image. • The central part of the laser printer is its electro photographic drum. (a metal cylinder that is coated with a light-sensitive insulating material) • When a beam of laser light strikes the drum, it becomes a conductor at the point where the light hits it. • As the drum rotates, the laser beam draws an electrostatic image called the image. The undeveloped or latent image is passed by a supply of dry ink or toner that is attracted to it. • The drum turns and brings this image in contact with the paper, which attracts the toner. • The paper is passed through a fuser that is made up of hot rollers, which melts the toner into the paper.
Laser Printing Process • Cleaning-remaining toner must be removed from the drum. (by a blade to scrape all excess toner from the drum or wire that uses AC voltage to remove the charge from the drum surface and allows the excess toner to fall away from the drum. (Stored in a used toner container) • Conditioning-removing the old latent image from the drum and clearing or conditioning the drum for a new latent image. (Does this by placing a special wire, grid, or roller that is charged to about –6000 volts DC uniformly across the surface of the drum (referred to as the primary corona)
Laser Printing Process • Writing-scanning the photosensitive drum with the laser beam (As the drum turns, an invisible latent image is created on the drum ) • Developing-toner is applied to the latent image. Inside the toner unit are developer particles made up of magnetic materials. These magnetic particles are coated with a plastic-like material. A triboelectric charge on the developer particles causes it to attract toner.
Transferring and Fusing with Laser • Transferring: the toner attached to the latent image is transferred to the paper. The transfer or secondary corona places a positive charge on the paper. Since the drum was charged negatively, it attracts the negative toner image from the drum to the paper. The image is now on the paper and is held in place by the positive charge. • Fuser: images are made permanent. The printing paper is rolled between a heated roller and a pressure roller. As the paper rolls, the top fuser roller is heated to about 350 degrees, which melts the loose toner powder fusing with the fibers in the paper. • “Continuous Care Will Delay Trouble Forever.”
Print Capacity and Speed • If speed is an important consideration, lower-end inkjet printers are not a good choice. • Inkjet printers will print text at two to six pages per minute (ppm). Printing a page of graphics can take several minutes. • Color laser printers, which may be able to print at 16 ppm and send out the first page in about ten seconds. A production printer prints 50,000 or more pages per week. (used by commercial publishers.) cost $100,000 and up. print up to 700 ppm and are capable of printing 24 hrs, 7 days a week.
Printer Resolution and Cost • There are inkjet printers that are specially designed to produce top quality photos, but these units tend to do poorly on printing text. • Resolution: refers to the number of tiny dots the print-head is capable of fitting per inch when forming an image. • Laser printers = 600 dots per inch (dpi). (sufficient for normal everyday printing including small desktop publishing jobs) • High-end production printer = 2400 dpi. • The higher the resolution is, the higher the image quality. Unless photo quality is required, the standard resolution of 600 by 600 will be more than adequate for most printing. • More economical to spend U.S. $900 on a printer that can last for 5 years than it is to spend U.S. $250 each year to replace a printer that is worn out or broken. • Check the related costs such as cartridges, toner, replacement parts, printing paper, and so on. (Total Cost of Ownership (TCO).)-cheaper to replace just the color that is needed
Differences Laser vs. InkJet • The toner or ink in a laser printer is dry. In an inkjet, it is wet. • An inkjet printer is about ten times more expensive to operate, over time, than a laser printer because ink needs replenishing more frequently. • The printed-paper from an inkjet printer might smear if it is wet. A laser printed document will not. • An inkjet printer is sufficient if the printing needs are minimal. However, if printing volume is high, a laser printer would be a better choice. • In terms of similarities, however, both inkjet and laser printers operate quietly and allow fonts to be added by using font cartridges or installing soft fonts.
Serial Connection of a Printer • Serial ports are usually found on dot matrix printers that do not require high-speed transfers of data. • Data transfer moves single bits of information in a single cycle. • Serial ports are D-shell ports that are categorized as either male or female and also by the number of pins available for each port. • Common serial cables include 9-pins on both ends, 25-pins on both ends, and a combination of the two. • Usually, the ends of the printer cables are secured to the ports on the printer and PC with thumbscrews. • Maximum length of serial cable is 50 feet (18 meters).
Parallel Connection of a Printer • Faster data transfer rates than serial printers because parallel data transfer moves multiple bits of information in a single cycle. • IEEE 1284 is the current standard for parallel printer cables. The maximum length for IEEE 1284 cables is 3 meters (15 feet). • Cables have two unique ends: • a 1284 Type-A 25-pin DB 25 connector. (Connects to the PC or daisy-chained peripheral and has two screws that should be hand-tightened.) - -36-conductor Centronics connector. (Connects to the printer and should be secured in place with the port clips)
SCSI • Small Computer System Interface (SCSI) uses parallel communication technology to achieve high data transfer rates. The most common are the following: • SCSI 1 or plain SCSI • SCSI 2 or wide SCSI • SCSI 3 or fast SCSI • SCSI printers and computers require the proper cabling for the ports. These ports can be DB 50, Mini DB 50, and DB 68. All of these ports may be male or female.
Firewire • (i.LINK or IEEE 1394) is a high-speed, platform-independent communication bus that interconnects digital devices such as digital printers, scanners, digital cameras, hard drives, and so on. • Developed by Apple, FireWire was designed to allow peripherals to seamlessly plug into a computer. • It also allows a device such as printer to be hot-plugged with a single plug-and-socket connection on which up to 63 devices can be attached with data transfer speeds up to 400 Mbps. • In the future, IEEE 1394 implementations are planned to replace and consolidate serial and parallel interfaces, such as Centronics parallel, RS-232C, and SCSI. • The first printers to be introduced with FireWire are just beginning to come on the market.
USB • Universal Serial Bus (USB) is a very common communication type for not only printers but also other devices due to its speed and ease of setup. • Newer operating systems offer plug-and-play USB support. • When a device is added to a computer system via USB, it is automatically detected, and the driver installation process begins. • A USB cable is a four-wire cable that has two unique ends. The slimmer end connects to the PC. The wider end, which is square, connects to the printer. These ends are keyed so that they can only fit one way into each port.
Network • Network printers are commonly used in the workplace because they act as shared resources for all users on the network. • They have high-speed outputs and offer many options, such as LAN fax, duplex, and finishers. • Connecting a printer to the network requires the correct type of cabling that is compatible with the existing network. (An RJ-45 interface for connection into an Ethernet network.) • Other connection options include Bayonet Neill-Concelman or British Naval Connectors (BNC) and Token Ring ports. • The maximum length (Cat 5)to connect a printer to the network is 328 feet (100 meters).
Infrared • Current wireless printing technology is built upon infrared technology, which uses a spectrum of light invisible to the human eye. • For infrared communication to take place between a printer and a computer, transmitters and receivers are required on both devices. • When setting up an infrared printer, there must be a clear line of sight between the transmitters and receivers on both devices with a maximum distance of 4.5 meters (15 feet).
PDL • Page Description Language • code that describes the contents of a document in a language that a printer can understand. (include text, graphics, and the overall formatting of the document) • PDLs are used by software applications to send What You See Is What You Get (WYSIWYG) images to the printer so that the printer output mirrors the document laid out on the screen. • speed up the printing process by sending larger amounts of data to the printer at a time. • handle fonts used by the printer. (various sizes and weights without lowering the quality) Fonts are either raster-based consisting of multiple dots or vector-based consisting of complicated, outline-oriented fonts.
Printer Drivers • Printer drivers are software programs that allow the computer and printer to communicate. • These programs also provide the user with an interface to configure the printer options. • Every printer model has its own unique driver program. • Printer manufacturers frequently update drivers to increase the performance of the printer, add new and improved printer options, and to address general compatibility issues. • These drivers can be downloaded from the printer manufacturer website.
Printer Cartridges • Inkjet printer cartridges can be fragile. • Do not touch the print-head or foil contacts. • install the correct color cartridge in the correct slot in the printer. • Printer ribbons should be handled on the plastic ends only. • Check the expiration date. Any guarantee is void after this date. • Ink cartridges, toner units, and ribbons should be recycled according to the environmental recommendations. • Laser printer toner units should be shaken vigorously in a side-to-side manner to evenly distribute the toner inside the hopper. If toner spills out of the cartridge, it can be wiped up with a damp cloth.
Adding Printer Memory • All printers now have at least a small amount of RAM. Generally, the more memory a printer has, the more efficiently it works • Memory type –physical type of memory, speed, and capacity. Some printer manufacturers use standard types of memory in while others require the use of special or proprietary memory. • Memory population and availability – If a printer has multiple memory upgrade options or slots, it is important to know how many slots are used and how many are available. This may require opening a compartment on the printer to check RAM population. • Proper procedures – Each printer manufacturer has its own set of procedures for memory upgrades. (The procedure list)
Add a Local Printer • In Windows 2000, go to the Start > Settings > Printers • Double-click on the Add Printer button. The Add Printer Wizard will launch • It will then ask whether the printer to be added is local or part of the network. If the printer is directly connected to the computer other than through a network port, choose local • Choose the port to be assigned. (the most common port for local printers, which is LPT1) • The printer manufacturer and model type must be provided. Choose the exact model from the list. If the model does not display, check the user guide that came with the printer for guidance or choose a model from the same manufacturer with a similar name. • The wizard will notify the user that the printer is now ready to use • Print a test page
Printing a Test Page • In Windows, click Start, select Settings, and choose the Printers folder. • Or, double-click to open My Computer and then open the Printers folder. Right-click on the icon of the printer and choose Properties. This will open a dialog box containing most of the customizable features of that particular printer. • Near the bottom of the General tab there will be a button labeled Print Test Page. Clicking on this button will initiate the printing of a test page, which is followed by another dialog box asking the user if the page printed correctly. • If not, the built-in help files will walk the user through the troubleshooting steps.
Printing Through a Command Line • Printing from the command line is limited to ASCII files only, such as .txt and .bat files. • To begin a command line session in Windows, click Start, choose Run, type in COMMAND.COM, and click OK. This opens up a shell session. At the command line prompt, type the following command: • type thefile.txt > prn • type – This types the file to an output device. • thefile.txt – This is the ASCII file to be printed. • > – This redirects the file to a specific output device. • prn – This sets the printer to be the output device.
Host-Based Printing • Host-based printing, also known as Graphical Device Interface (GDI) printing, is a technology in which the operating system communicates directly with the printer and sends the printer an image that is ready to print. • Disadvantages: A printer-specific driver must be installed. Also host-based printers placed on a network require a direct connection to a host and require that printer sharing is configured. This host then becomes a print server, which can limit the role that the computer can perform.
Printer Switches • Highly desirable to have multiple printers available to handle different types of print jobs • A printer switch (A/B switch or data switch) is a piece of hardware that is used to take data input from one or more devices and route it to one or more output devices(printers, Zip drives, scanners, or CDR drives) • Easiest method of having access to multiple printers on a single host is through the use of a parallel printer switch • The port the host connects to is labeled “Input” or “Host”, and the output ports are usually labeled “A” and “B”. • Rules: A printer switch can only output to one device at a time; each printer or other device connected to the switch must be installed and configured properly on the host (correct printer and device drivers); the correct printer must be chosen for each print job;printer and switch must be compatible; laserprinters do not operate well with mechanical switches.
Print Sharing • For print sharing to work, special software must be installed and configured on the print server. Then the clients must be configured to be able to access the printer located on the print server. (Windows 200 operating systems have printer-sharing capability built-in.) • To install File and Print Sharing or to verify that it is installed on a Windows 9x computer, right-click on My Network Places in Windows ME or Network Neighborhood in Windows 95/98 and choose Properties. • If it is not installed, the user can easily do so by clicking the FileandPrint Sharing button and check either "I want to be able to give others access to my files.", or "I want to be able to allow others to print my from printer(s).", or both. • In the Printers folder, right-click on the printer to share, choose Properties, and select the Sharing tab. Choose the option to share the printer and assign it a unique name. • Finally, each client computer that will access the printer must have the correct printer drivers installed. Begin the Add Printer Wizard to find and install the shared printer.
Adding a Network Printer • A network printer is attached directly to the network, as are the client workstations. • Simply connecting a printer to a print server is not all that is involved to allow printing over the network. The network operating system has utilities that allow network printing to be set up and managed. • The application formats the document to be printed into data that the printer can understand and sends it out. • The redirector in the computer sends the data out on the network, and it then travels to the print server. • The print spooler in the software on the print server places the data in a print queue, which are print jobs waiting to be processed. • The print data is held in the print queue until the printer is ready to print it.
Network Print Server • A network print server is a computer dedicated to handling client print jobs in the most efficient manner. • Since it handles requests from multiple clients, a print server is usually one of the most powerful computers on the network. A print server should have the following components: A powerful processor, adequate hard disk space,adequate memory • Has two purposes: first is to provide client access to print resources, and the second is to provide feedback to the users.
Printer Network Interface Cards • Must have the proper type of port for network connection. • A printer network interface card (NIC) is an adaptor that the printer uses to access the network media. • This NIC may be built into the printer or come in the form of an expansion card. • Currently, the most commonly used printer NICs have RJ-45 ports to connect into copper-based Ethernet networks • Usually, connecting the printer NIC to a network hub or switch with a Category 5 cable provides the connection. Other printer NIC types include the following: • BNC • RJ-11, which is 4-wire telephone cabling • Wireless
Printer Queue • Temporary holding area for print jobs • The jobs in the queue are fed to the printer when it is ready for the next job. • “Queue” is an area of memory set aside on the print server for managing print jobs. • When a user decides to print a document, it is immediately sent to the printer queue. If there are no other jobs in the queue, it is processed at once. Printer queues, by default, use the first in, first out (FIFO) rule. • Also a management tool that can be used to view and manipulate print jobs : delete, rearrange, pause • It is important that managing the printer queue is restricted to just a few individuals like the network administrator The network administrator can then determine the priority of users and print jobs. (priority to all would allow users to then prioritize their jobs or delete other jobs that were sent to the printer
Setting a Default Printer • Choosing or changing the default printer on a computer can be done in three ways: • Designating during printer installation • Selecting manually- A list of installed printer icons can be seen by clicking Start > Settings > Printer or opening the Control Panel from the Windows 9x desktop. The current default printer will have a small check mark in a dark circle on its icon Designating a new default printer can be done by right-clicking on the printer icon and choosing Set as Default. • Using the printer queue – When viewing the queue of a particular printer, it can be designated as the default printer by choosing Printer from the menu bar and selecting Set as Default.
Printer Options • In general, media handling options are used to set the way a printer handles the media and can include the following: Input paper tray selection, output path selection, media size and orientation, paper weight selection • Printer output options deal with how the ink or toner is placed on the media and include these common printer output options: Color management, Print quality, Print speed
Paper Problems • A large majority of printer problems are paper jams. In fact, a lot of the problems are related to the paper itself. • Parts that drive paper movement may fail and cause paper to crumple or z-fold in the process of moving through the path. This will shut the printer down and require removal of any paper trapped in the process. • Never remove any paper jam by pulling in the opposite direction. The printer gears could be damaged • A paper jam can occur when the wrong type of paper is used. This can cause more than one page to enter the registration rollers. This is called paper clumping. A bad separator pad can also cause clumping and should be replaced. • Most of the problems in laser printers that require service are rooted in the paper dust that is accumulated in the paper path. This paper dust requires regular cleaning to prevent costly service at a later date. (At some point, this dust will fall back into the paper path causing jams) • When clumping or other jam failures occur, the drive system can overload. This can result in teeth being stripped from a gear or a broken gear. The only solution is to replace the gear.
Stepper Motor Problems • Stepper motors are used in printers to position the head as well as moving paper through the printer • Overloading, however, can damage the motor. In this situation, replacement of the motor is required. (An average technician will not attempt to fix this...)
