Characteristics of Printers (8.1.1.1)

Computer technicians are often required to select, purchase, and install printers for the users. Technicians need to know how to configure, troubleshoot, and repair the most common types of printers. Most printers available today are either laser printers using imaging drums or inkjet printers using electrostatic spray technology. Dot matrix printers using impact technology are used in applications that require carbon copies. Thermal printers are commonly found in retail, typically used to print receipts. 3D printers are used in design and manufacturing. Figure 8-1 shows examples of these five types of printers.

Printer Speed, Quality, and Color (8.1.1.2)

Printer speed is a factor to consider when selecting a printer. The speed of a printer is measured in pages per minute (PPM). Printer speed varies between makes and models. Speed is also affected by the complexity of the image and the quality desired by the user. The quality of printing is measured in dots per inch (dpi). The larger the dpi number, the better the image resolution. When the resolution is higher, text and images are clearer. To produce the best high-resolution images, use high-quality ink or toner and high-quality paper.

The color printing process uses the primary colors cyan, magenta, and yellow (CMY). For inkjet printing, the color black serves as the base or key color. Thus, the acronym CMYK refers to the inkjet color printing process. Figure 8-2 shows a CMYK color wheel.

Reliability and Total Cost of Ownership (8.1.1.3)

A printer should be reliable. Because so many types of printers are on the market, it is important to research the specifications of several printers before selecting one. Here are some manufacturer options to consider:

• Warranty: Identify what is covered in the warranty.

• Scheduled servicing: Servicing is based on expected usage. Usage information is in the documentation or on the manufacturer’s website.

• Mean time between failures (MTBF): A printer should work without failing for an average length of time. Information about the MTBF is provided in the documentation or on the manufacturer’s website.

When buying a printer, there is more than just the initial cost of the printer to consider. The total cost of ownership (TCO) includes a number of factors:

• Initial purchase price

• Cost of consumable supplies, such as paper and ink (see Figure 8-3)

  

• Pages per month

• Price per page

• Maintenance costs

• Warranty costs

When calculating the TCO, consider the amount of printing required and the expected lifetime of the printer.

Automatic Document Feeder (8.1.1.4)

An automatic document feeder (ADF) can be found on some laser and inkjet printers that also have the capabilities of copy machines. The ADF is a slot where an existing document can be placed, as shown in Figure 8-4. The machine is then set to make copies of this document.

When the print process is started, the ADF pulls one page of the document onto the glass surface of the platen, where it is scanned and copies are made. The page on the platen is then automatically removed, and the next page in the original document is pulled onto the platen. This process continues until the entire original document in the feeder has been pulled through. Some machines can make multiple copies. Usually these machines can also collate these copies.

Depending on the capabilities of the machine, the original document may be placed face up in the feeder or face down. The machine may have a limit as to how many pages can be put in the ADF at a time.

Printer Connection Types (8.1.2.1)

A printer must have a compatible interface with the computer. Typically, a printer connects to a home computer using a USB or wireless interface. However, a printer may also connect directly to a network, using a network cable or a wireless interface, as shown in Figure 8-5.

Serial Connectors

A serial connection can be used for dot matrix printers because the printers do not require high-speed data transfer. A serial connection, shown in Figure 8-6, for a printer is often referred to as COM. Serial ports are generally found on legacy computer systems.

Parallel Connectors

With a parallel connection, the data transfer path is wider than a serial data transfer path, allowing data to move more quickly to or from the printer.

IEEE 1284 is the standard for parallel printer ports. Enhanced Parallel Port (EPP) and Enhanced Capabilities Port (ECP) are two modes of operation within the IEEE 1284 standard that allow bidirectional communication. A parallel connection for a printer is often referred to as LPT. Parallel ports, shown in Figure 8-7, are generally found on legacy computer systems.

USB Connectors

USB, shown in Figure 8-8, is a common interface for printers and other devices. When a USB device is added to a computer system that supports Plug and Play, the device is automatically detected and starts the driver installation process.

FireWire Connectors

FireWire, also known as i.LINK or IEEE 1394, is a high-speed communication bus that is platform independent. FireWire, shown in Figure 8-9, connects digital devices such as printers, scanners, cameras, and hard drives.

Ethernet Connectors

With an Ethernet connection, connecting a printer to the network requires cabling that is compatible with both the network and the network port installed in the printer. Most network printers use an RJ-45 interface to connect to a network, as shown in Figure 8-10.

Wireless Connections

Many printers come with built-in wireless capability, which enables them to be connected to a Wi-Fi network, as shown in Figure 8-11. Some printers come equipped with the ability to connect to devices through Bluetooth pairing.

8.1.2.2 Check Your Understanding - Printer Connections

Refer to the online course to complete this activity.

Inkjet Printer Characteristics (8.2.1.1)

Inkjet printers are easy to use and usually less expensive than laser printers. Figure 8-12 shows an all-in-one device that contains an inkjet printer.

Some advantages of an inkjet printer are the initial low cost, high resolution, and short warmup time. Some disadvantages of an inkjet printer are that the nozzles are prone to clogging, ink cartridges can be expensive, and the ink is wet for a few seconds after printing.

Inkjet Printer Parts (8.2.1.2)

The sections that follow illustrate and describe the main components of an inkjet printer.

Ink Cartridges/Paper

Paper and ink cartridges, shown in Figure 8-13, are the primary consumable items in an inkjet printer. Ink cartridges are designed for specific makes and models of inkjet printers. Most inkjet printers use plain paper for printing. Some can also print images on high-quality photo paper. Consult your printer’s manual for the correct type of ink cartridges and paper to use.

If inkjet printer quality degrades, check the printer calibration by using the printer software.

Print Head

Inkjet printers use ink cartridges that spray ink onto a page through tiny holes. The tiny holes are called nozzles and are located in the print head, shown in Figure 8-14.

There are two types of inkjet nozzles:

• Thermal: A pulse of electrical current is applied to heating chambers around the nozzles. The heat creates a bubble of steam in the chamber. The steam forces ink out through the nozzle and onto the paper.

• Piezoelectric: Piezoelectric crystals are located in the ink reservoir at the back of each nozzle. A charge is applied to the crystals, causing them to vibrate. This vibration of the crystals controls the flow of ink onto the paper.

Roller

Rollers, shown in Figure 8-15, pull paper in from the feeder.

Feeder

The feeder, shown in Figure 8-16, may hold blank paper in a tray or cassette. Some inkjet printers are also copiers. In addition, an inkjet printer may have an automatic document feeder (ADF). The ADF holds documents, which are fed page by page onto the scanner bed for copying.

Duplexing Assembly

Some inkjet printers can print on both sides of a page. This requires a duplexing assembly, shown in Figure 8-17, which turns a printed page over and feeds it back through the printer to be printed on the other side.

Carriage/Belt

The print head and ink cartridges are located on the carriage, which is attached to a belt and motor, as shown in Figure 8-18. The belt moves the carriage back and forth across the paper as the ink is sprayed on it.

8.2.1.3 Check Your Understanding - Inkjet Printers

Refer to the online course to complete this activity.

Laser Printer Characteristics (8.2.2.1)

A laser printer, shown in Figure 8-19, is a high-quality, fast printer that uses a laser beam to create an image.

Some advantages of a laser printer are low cost per page, high number of pages printed per minute, high capacity, and dry printed pages. Some disadvantages of a laser printer are high cost of startup and potentially expensive toner cartridges.

Laser Printer Parts (8.2.2.2)

The sections that follow illustrate and describe the main components of a laser printer.

Imaging Drum

The central part of the laser printer is its imaging drum, shown in Figure 8-20. The drum is 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.

Toner Cartridge/Paper

As the drum rotates, the laser beam draws an electrostatic image on the drum. This undeveloped image is passed by a supply of toner. The toner is a negatively charged combination of plastic and metal particles. The electrostatic charge attracts toner to the image. The drum turns and brings the exposed image in contact with the paper, which attracts the toner from the drum.

The toner cartridge (see Figure 8-21) and paper are the primary consumable items in a laser printer. Other parts may also be contained in the toner cartridge. Check your printer’s manual for more information.

Fuser Assembly

The paper is passed through a fuser assembly, shown in Figure 8-22, that is made up of hot rollers, which melt the toner into the paper.

Transfer Roller

The transfer roller, shown in Figure 8-23, assists in transferring the toner from the imaging drum to the paper.

Pickup Rollers

Pickup rollers, shown in Figure 8-24, may be located in multiple areas of a printer. They move the sheet of paper out of the tray or cassette and through the printer during the printing process.

Duplexing Assembly

The duplexing assembly, shown in Figure 8-25, turns a page that is already printed on one side so that it can be printed on the other side.

8.2.2.3 Check Your Understanding - Laser Printers

Refer to the online course to complete this activity.

How Laser Printing Works (8.2.3.1)

The laser printer process involves seven steps to print information onto a single sheet of paper.

1. Processing (see Figure 8-26): The data from the source must be converted into a printable form. The printer converts data from common languages, such as Adobe PostScript (PS) or HP Printer Command Language (PCL), to a bitmap image stored in the printer’s memory. Some laser printers have built-in Graphical Device Interface (GDI) support. Windows applications use GDI to display printed images on a monitor, so there is no need to convert the output to another format, such as PS or PCL.

   

2. Charging (see Figure 8-27): The image on the drum is removed, and the drum is conditioned for the new image. A wire, grid, or roller receives a charge of approximately –600 volts DC uniformly across the surface of the drum. The charged wire or grid is called the primary corona. The roller is called a conditioning roller.

   

3. Exposing (see Figure 8-28): To write the image, the photosensitive drum is exposed with the laser beam. Every portion of the drum that is scanned with the light has the surface charge reduced to about –100 volts DC. This electrical charge has a lower negative charge than the rest of the drum. As the drum turns, an invisible image is created on the drum.

   

4. Developing (see Figure 8-29): The toner is applied to the image on the drum. A control blade holds the toner at a microscopic distance from the drum. The toner then moves from the control blade to the more positively charged image on the drum.

   

5. Transferring (see Figure 8-30): The toner, attached to the image, is transferred to the paper. The corona wire places a positive charge on the paper. Because the drum was charged negatively, the toner on the drum is now attracted to the paper. The image is now on the paper and is held in place by the positive charge. Because color printers have three cartridges of toner, a colored image must go through multiple transfers to be complete. To ensure precise images, some color printers write multiple times onto a transfer belt that transfers the complete image to paper.

   

6. Fusing (see Figure 8-31): The toner is permanently fused to the paper. The printing paper is rolled between a heated roller and a pressure roller. As the paper moves through the rollers, the loose toner is melted and fused with the fibers in the paper. The paper is then moved to the output tray as a printed page. Laser printers with duplex assemblies can print on both sides of a sheet of paper.

   

7. Cleaning (see Figure 8-32): When an image has been deposited on the paper and the drum has separated from the paper, the remaining toner must be removed from the drum. A printer might have a blade that scrapes the excess toner. Some printers use AC voltage on a wire to remove the charge from the drum surface and allow the excess toner to fall away from the drum. The excess toner is stored in a used toner container that is either emptied or discarded.

   

Thermal Printer Characteristics (8.2.4.1)

Many retail cash registers and some older fax machines contain thermal printers, shown in Figure 8-33). Thermal paper is chemically treated and has a waxy quality. Thermal paper becomes black when heated. After a roll of thermal paper is loaded, the feed assembly moves the paper through the printer. Electrical current is sent to the heating element in the print head to generate heat. The heated areas of the print head make the image on the paper.

Some advantages of thermal printers are that they last a long time because there are few moving parts, their operation is quiet, and there is no cost for ink or toner. However, thermal paper is expensive, it must be stored at room temperature, and it can degrade over time. Thermal printer images are poor quality, and color printing is not available.

Impact Printer Characteristics (8.2.4.2)

Impact printers have print heads that strike an inked ribbon, causing characters to be imprinted on the paper. Dot matrix and daisy wheel are examples of impact printers.

An advantage of impact printers is that the ribbon is less expensive than inkjet cartridges or laser printer toner cartridges. In addition, these printers can use continuous feed or normal sheets of paper and can print carbon copies. Disadvantages include the fact that they are noisy, the graphics are low resolution, and they have limited color printing capabilities.

A dot matrix printer (see Figure 8-34) has a print head containing pins that are surrounded by electromagnets. When energized, the pins push forward onto the ink ribbon, creating a character on the paper. The number of pins on a print head, 9 or 24, determines the quality of the print. The highest quality of print that is produced by a dot matrix printer is referred to as near letter quality (NLQ).

Most dot matrix printers use continuous-feed paper, also known as tractor feed. The paper has perforations between sheets, and perforated strips on the side are used to feed the paper and to prevent skewing or shifting. Sheet feeders that print one page at a time are available for some higher-quality printers. A large roller, called the platen, applies pressure to keep the paper from slipping. If a multiple-copy paper is used, you can adjust the platen gap to the thickness of the paper.

Virtual Printer Characteristics (8.2.5.1)

Virtual printing does not involve sending a print job to a printer within your local network. Instead, the print software either sends the job to a file or transmits the information to a remote destination in the cloud for printing.

Typical methods for sending a print job to a file include the following:

• Print to file: Originally, print to file saved the data in a file with the .prn extension. The .prn file then could be quickly printed at any time without opening the original document. Print to file can now save in other formats, as shown in Figure 8-35.

• Print to PDF: Adobe’s Portable Document Format (PDF) was released as an open standard in 2008.

• Print to XPS: Introduced by Microsoft in Windows Vista, the XML Paper Specification (XPS) format was meant to be an alternative to PDF.

• Print to image: To prevent others from easily copying the content in a document, you can choose to print to an image file format, such as JPG or TIFF.

Cloud Printing (8.2.5.2)

Cloud printing is sending a print job to a remote printer, as shown in Figure 8-36. The printer could be at any location within your organization’s network. Some printing companies provide software that you can install and use to send print jobs to their closest location for processing.

Another cloud printing example is Google Cloud Print, which allows you to connect your printer to the Web. After it is connected, you can send print jobs to your printer from anywhere that has Internet access.

3D Printer Characteristics (8.2.6.1)

3D printers, shown in Figure 8-37, are used to create three-dimensional objects. These objects are first designed using a computer. A variety of media are now available to create these objects. For beginners, plastic filament is the most commonly used 3D printer medium. The plastic filament is added in layers to create the object that was programmed on the computer.

Traditionally, machines cut or drilled pieces out of raw material (such as stone, metal, or wood) to create an object. This is known as subtractive manufacturing. 3D printers add the material used to create objects in layers or even small bits; therefore, they are known as additive manufacturing machines.

3D Printer Parts (8.2.6.2)

The main parts of 3D printers are as follows:

• Filament: This is the material used in 3D printers to create objects. Common types of filament are plastic-based: ABS, PLA, and PVA (see Figure 8-38). There are even filaments made of nylon, metal, or wood. Check your 3D printer’s manual to determine which type(s) of filament to use.

• Feeder: The feeder (see Figure 8-39) takes filament from a feed tube that is placed into the extruder. The feeder pulls it down to be heated and then sends it through the hotend nozzle.

• Hotend nozzle: When the filament is heated to the correct temperature, it is extruded from the hotend nozzle, shown in Figure 8-40.

• Axis: An axis is one of several bars on which the hotend nozzle travels to dispense filament, as shown in Figure 8-41. An axis is either vertical or horizontal so that the hotend nozzle can be located within a specified location in a 3D environment to “print” the object.

• Print bed: The print bed, shown in Figure 8-42, is the platform onto which the heated filament forms the object.

Installing a Printer (8.3.1.1)

When you purchase a printer, the installation and configuration information is usually found on the manufacturer’s website. Before you install a printer, remove all packing material. Remove anything that prevents moving parts from shifting during shipping. Keep the original packing material in case you need to return the printer to the manufacturer for warranty service.

If the printer has a USB, FireWire, or parallel port, connect the corresponding cable to the printer port. Connect the other end of the data cable to the corresponding port on the back of the computer. If you are installing a network printer, connect the network cable to the network port.

After the data cable has been properly connected, attach the power cable to the printer. Connect the other end of the power cable to an available electrical outlet. When you turn on the power to the device, the computer determines the correct device driver to install.

Test Printer Functions (8.3.1.2)

The installation of any device is not complete until you have successfully tested all its functions. Depending on the printer you have, functions might include the following (see Figure 8-43):

• Printing double-sided documents

• Using different paper trays for different paper sizes

• Changing the settings of a color printer so that it prints in black and white or grayscale

• Printing in draft mode

• Using an optical character recognition (OCR) application

• Printing a collated document

Functions for an all-in-one printer include the following:

• Faxing to another known working fax

• Creating a copy of a document

• Scanning a document

• Printing a document

Common Configuration Settings (8.3.2.1)

Check the printer documentation for specific information about its configuration and default settings. Table 8-1 shows some common configuration options available for printers.

Common printer options that the user can configure include media control and printer output.

Software Optimization (8.3.3.1)

With printers, most optimization is completed through the software that comes with the drivers.

The following tools optimize performance:

• Print spool settings: Cancel or pause current print jobs in the printer queue.

• Color calibration: Adjust settings to match the colors on the screen to the colors on the printed sheet.

• Paper orientation: Select landscape or portrait image layout, as shown in Figure 8-44.

Printers are calibrated using the printer driver software. Calibration makes sure that the print heads are aligned and that they can print on different kinds of media, such as cardstock, photographic paper, and optical discs. Some inkjet print heads are fitted to the ink cartridge, and you might have to recalibrate the printer each time you change a cartridge.

Hardware Optimization (8.3.3.2)

Some printers can be upgraded to print faster and to accommodate more print jobs by adding hardware. The hardware may include additional paper trays, sheet feeders, network cards, and expansion memory.

The procedure to upgrade firmware is similar to the procedure to install printer drivers. Firmware updates do not take place automatically, so you can visit the home page of the printer manufacturer to check the availability of new firmware.

All printers have RAM, such as the chips shown in Figure 8-45. Printers usually arrive from the factory with enough memory to handle jobs that involve text. However, print jobs involving graphics, and especially photographs, run more efficiently if the printer memory is adequate to store the entire job before it starts. Upgrading the printer memory increases the printing speed and enhances complex print job performance.

Print job buffering involves capturing a print job in the internal printer memory. Buffering is a common feature in laser printers and plotters, as well as in advanced inkjet and dot matrix printers.

Low memory errors can indicate that the printer is out of memory or has a memory overload. In such a case, you may need more memory.

Configuring Printer Sharing (8.4.1.1)

Windows allows computer users to share their printers with other users on the network.

Users who cannot connect to a shared printer might not have the required drivers installed. They might also be using different operating systems than the computer that is hosting the shared printer. Windows can automatically download the correct drivers to these users. Accessing Printer properties will take the user to the Additional Drivers button to select operating systems that the other users are using. Clicking this button and selecting their OS and then closing the dialog box and clicking OK, Windows asks to obtain those additional drivers and downloads them. If other users are also using the same Windows operating system, they will not need to click the Additional Drivers button.

Figure 8-46 and Figure 8-47 show how to begin the process of printer sharing in Windows 10.

There are potential data privacy and security issues to consider when sharing printers:

• Hard drive caching: Cached print files pose privacy and security risks because someone with access to the device could recover files and then access confidential or personal information.

• User authentication: To prevent unauthorized use of a network or cloud-based printer, permissions and user authentication methods can be used to control access to the printer.

• Data privacy: Print jobs sent over a network could be intercepted and read, copied, or modified.

Wireless Printer Connections (8.4.1.2)

Wireless printers enable hosts to connect and print wirelessly using Bluetooth or a Wi-Fi connection. For wireless printers to use Bluetooth, both the printer and the host device must have Bluetooth capabilities, and they must be paired. If necessary, you can add a Bluetooth adapter to a computer, usually in a USB port. Wireless Bluetooth printers also allow for printing from mobile devices.

Wireless printers that use Wi-Fi connect directly to a wireless router or an access point. Setup is completed by connecting the printer to the computer with the supplied software or by using the printer display panel to connect to the wireless router. The printer’s wireless adapter supports an 802.11 standard. The devices connecting to the printer must also support the same standard.

In wireless infrastructure mode, the printer is configured to connect to an access point. Client connections to the printer go through the access point. In wireless ad hoc mode, client devices connect directly to the printer, as shown in Figure 8-48.

Purposes of Print Servers (8.4.2.1)

A printer that does not have built-in network interfaces may require a separate print server to enable network connectivity. Print servers let multiple computer users, regardless of device or operating system, access a single printer (see Figure 8-49). A print server has three functions:

• Providing client access to print resources

• Administering print jobs by storing them in a queue until the print device is ready for them and then feeding or spooling the print information to the printer

• Providing feedback to users about the state of the printer

Sharing a printer from a computer also has disadvantages. The computer sharing the printer uses its own resources to manage the print jobs coming to the printer. If the computer user on the desktop is working at the same time as a user on the network is printing, the desktop computer user might notice a performance slowdown. In addition, the printer is not available if the user reboots or powers off the computer that shares the printer.

Software Print Servers (8.4.2.2)

In some instances, the computer sharing a printer is running an operating system that is not Windows, such as macOS. In such a case, you can use print server software. One example is Apple’s free Bonjour Printer Server, which is a built-in service in macOS. It is automatically installed on a Windows computer if you install the Apple Safari browser. You can also download Bonjour Print Services for Windows, as shown in Figure 8-50, for free from the Apple website.

When it is downloaded and installed, Bonjour Print Services operates in the background, automatically detecting any compatible printers connected to the network.

Hardware Print Servers (8.4.2.3)

A hardware print server is a simple device with a network card and memory. It connects to the network and communicates with the printer to enable print sharing. The print server in the Figure 8-51 is connected to the printer by a USB cable. A hardware print server may be integrated with another device, such as a wireless router. In this case, the printer would connect directly to the wireless router, most likely through a USB cable.

Apple’s AirPort Extreme is a hardware print server. Through the AirPrint service, AirPort Extreme can share a printer with any device on the network.

A hardware print server can manage network printing through either wired or wireless connections. An advantage of using a hardware print server is that the server accepts incoming print jobs from devices, thereby freeing the computers for other tasks. A hardware print server is always available to users, unlike a printer shared from a user’s computer.

Dedicated Print Servers (8.4.2.4)

For larger networking environments with multiple LANs and many users, a dedicated print server is needed to manage printing services (see Figure 8-52).

A dedicated print server is more powerful than a hardware print server. It handles client print jobs in the most efficient manner and can manage more than one printer at a time. A dedicated print server must have the following resources to meet the requests of print clients:

• Powerful processor: Because the dedicated print server uses its processor to manage and route printing information, it must be fast enough to handle all incoming requests.

• Adequate storage space: A dedicated print server captures print jobs from clients, places them in a print queue, and sends them to the printer in a timely manner. This process requires the computer to have enough storage space to hold these jobs until they are completed.

• Adequate memory: The processor and RAM handle sending print jobs to a printer. If there is not enough memory to handle an entire print job, the document is stored on the drive in the print server and printed from there. This is generally is slower than printing directly from memory.

Vendor Guidelines (8.5.1.1)

A good preventive maintenance program helps ensure good-quality prints and uninterrupted operation. The printer documentation contains information on how to maintain and clean the equipment.

Read the information manuals that come with every new piece of equipment. Follow the recommended maintenance instructions. Use the supplies listed by the manufacturer. Less expensive supplies can save money but may produce poor results, damage the equipment, or void the warranty.

Most manufacturers sell maintenance kits for their printers (see Figure 8-53). If you do not know how to maintain printing equipment, consult with a manufacturer-certified technician. When servicing toner kits and cartridges, wear air filter masks to avoid breathing in harmful particles.

What Do You Already Know? - Printer Operating Environment (8.5.1.2)

Printers are affected by temperature, humidity, and electrical interference. In fact, laser printers tend to create a great deal of heat and must be operated in a well-ventilated area, or they will overheat.

Paper is also affected by its environment. Although paper can withstand warm and cool temperatures, it is easily affected by humidity. Paper can absorb moisture from the air, which can cause pieces to stick together and sometimes jam during printing.

Toner is also affected by its environment, especially humidity. High humidity can prevent the toner from attaching to the paper correctly. It is therefore best to keep toner cartridges in their original wrappers and store them in a cool, dust-free environment, until you are ready to use them.

Dust is an environmental problem for all printers. Dusty conditions in and around a printer’s location, as well as dust from the printer paper, must be removed regularly. Use compressed air to blow dust away from the interior of a printer.

Preventive Maintenance on a Thermal Printer (8.5.4.1)

Always consult the thermal printer’s manual before performing maintenance tasks. The manual gives instructions that are specific to your thermal printer on how to replace the paper roll. Figure 8-54 shows a thermal printer’s paper being replaced.

Thermal printers use heat to create an image on special paper. To extend the life of the printer, dampen a cotton swab with isopropyl alcohol and use it to clean the heating element. Do this on a regular basis. The heating element is located near the slot where the printed paper emerges, as shown in Figure 8-55. While the printer is open, use compressed air or a lint-free cloth to remove any debris.

Preventive Maintenance of an Impact Printer (8.5.5.1)

Always consult the manual before performing maintenance tasks on an impact printer. The manual gives instructions that are specific to your impact printer. For safety reasons, it is always important to pay attention to the components that the manual indicates may be hot as they can cause you physical harm.

An impact printer is similar to a typewriter in that the print head strikes an inked ribbon to transfer ink to the paper. When an impact printer produces faded or light characters, the ribbon (see Figure 8-56) is worn out and needs to be replaced. Consult your manual for instructions on how to replace the ribbon.

If a consistent flaw is produced in all characters, the print head (see Figure 8-57) is stuck or broken and needs to be cleaned or possibly replaced. Search for procedures on dot matrix printhead cleaning to learn about this.

The Six Steps of the Troubleshooting Process (8.5.7.1)

The six steps of the troubleshooting process are as follows:

Step 1. Identify the problem.

Step 2. Establish a theory of probable cause.

Step 3. Test the theory to determine the cause.

Step 4. Establish a plan of action to resolve the problem and implement the solution.

Step 5. Verify full system functionality and, if applicable, implement preventive measures.

Step 6. Document findings, actions, and outcomes.

Identify the Problem (8.5.7.2)

Printer problems can result from a combination of hardware, software, and connectivity issues. A technician must be able to determine if a problem exists with the device, a cable connection, or the computer to which the printer is connected. Computer technicians must be able to analyze the problem and determine the cause of the error to repair the printer issues.

The first step in the troubleshooting process is to identify the problem. Table 8-2 shows a list of open-ended and closed-ended questions to ask the customer.

Establish a Theory of Probable Cause (8.5.7.3)

After you have talked to the customer, you can establish a theory of probable causes. Table 8-3 lists some common probable causes for printer problems. If necessary, conduct internal and external research based on the symptoms of the problem.

Test the Theory to Determine Cause (8.5.7.4)

After you have developed some theories about what is wrong, test them to determine the cause of the problem. Once a theory is confirmed, you can determine the steps to resolve the problem. Table 8-4 lists some quick procedures that can help you determine the exact cause of a problem or even correct the problem. If a quick procedure does correct the problem, you can verify full system functionality. If a quick procedure does not correct the problem, you may need to research the problem further to establish the exact cause.

Establish a Plan of Action to Resolve the Problem and Implement the Solution (8.5.7.5)

After you have determined the exact cause of a problem, establish a plan of action to resolve the problem and implement the solution. Table 8-5 shows some sources you can use to gather additional information to resolve an issue.

Verify Full System Functionality and, if Applicable, Implement Preventive Measures (8.5.7.6)

After you have corrected the problem, verify full functionality and, if applicable, implement preventive measures. Table 8-6 lists the steps to verify the solution.

Document Findings, Actions, and Outcomes (8.5.7.7)

In the final step of the troubleshooting process, document your findings, actions, and outcomes. Table 8-7 lists the tasks required to document a problem and its solution.

Identify Printer Problems and Solutions (8.5.8.1)

Printer problems can be attributed to hardware, software, networks, or some combination of the three. You will resolve some types of problems more often than others.

Common Problems and Solutions for Printers (8.5.8.2)

Table 8-8 documents some common printing problems and possible solutions.

Advanced Problems and Solutions for Printers (8.5.8.3)

Table 8-9 documents some advanced printing problems and possible solutions.