Print Head/Ink Cartridge

The first part of an inkjet printer is the one that people see the most: the print head. This part of a printer contains many small nozzles (usually 100 to 200) that spray the ink in small droplets onto the page. Many times, the print head is part of the ink cartridge, which contains a reservoir of ink and the print head in a removable package. Most color inkjet printers include multiple print heads, one for each of the CMYK(cyan, magenta, yellow, and black) print inks. The print cartridge must be replaced as the ink supply runs out.

Inside the ink cartridge are several small chambers. At the top of each chamber are a metal plate and a tube leading to the ink supply. At the bottom of each chamber is a small pinhole. These pinholes are used to spray ink on the page to form characters and images as patterns of dots, similar to the way a dot-matrix printer works but with much higher resolution.

There are two methods of spraying the ink out of the cartridge. Hewlett-Packard (HP) popularized the first method: When a particular chamber needs to spray ink, an electric signal is sent to the heating element, energizing it. The elements heat up quickly, causing the ink to vaporize. Because of the expanding ink vapor, the ink is pushed out of the pinhole and forms a bubble. As the vapor expands, the bubble eventually gets large enough to break off into a droplet. The rest of the ink is pulled back into the chamber by the surface tension of the ink. When another drop needs to be sprayed, the process begins again. The second method, developed by Epson, uses a piezoelectric element (either a small rod or a unit that looks like a miniature drum head) that flexes when energized. The outward flex pushes the ink from the nozzle; on the return, it sucks more ink from the reservoir.

When the printer is done printing, the print head moves back to its maintenance station. The maintenance station contains a small suction pump and ink-absorbing pad. To keep the ink flowing freely, before each print cycle, the maintenance station pulls ink through the ink nozzles using vacuum suction. The pad absorbs this expelled ink. The station serves two functions: to provide a place for the print head to rest when the printer isn’t printing and to keep the print head in working order.

Head Carriage, Belt, and Stepper Motor

Another major component of the inkjet printer is the head carriage and the associated parts that make it move. The print head carriage is the component of an inkjet printer that moves back and forth during printing. It contains the physical as well as electronic connections for the print head and (in some cases) the ink reservoir. Figure 11.3 shows an example of a head carriage. Note the clips that keep the ink cartridge in place and the electronic connections for the ink cartridge. These connections cause the nozzles to fire, and if they aren’t kept clean, you may have printing problems.

The stepper motor and belt make the print head carriage move. A stepper motor is a precisely made electric motor that can move in the same very small increments each time it is activated. That way, it can move to the same position(s) time after time. The motor that makes the print head carriage move is also often called the carriage motor or carriage stepper motor. Figure 11.4 shows an example of a stepper motor.

In addition to the motor, a belt is placed around two small wheels or pulleys and attached to the print head carriage. This belt, called the carriage belt, is driven by the carriage motor and moves the print head back and forth across the page while it prints. To keep the print head carriage aligned and stable while it traverses the page, the carriage rests on a small metal stabilizer bar. Figure 11.5 shows the stabilizer bar, carriage belt, and pulleys.

Paper-Feed Mechanism

In addition to getting the ink onto the paper, the printer must have a way to get the paper into the printer. That’s where the paper-feed mechanism comes in. The paper-feed mechanism picks up paper from the paper drawer and feeds it into the printer. This component consists of several smaller assemblies. First are the pickup rollers (see Figure 11.6), which are several rubber rollers with a slightly flat spot; they rub against the paper as they rotate and feed the paper into the printer. They work against small cork or rubber patches known as separator pads (see Figure 11.7), which help keep the rest of the paper in place so that only one sheet goes into the printer. The pickup rollers are turned on a shaft by the pickup stepper motor.

Sometimes the paper that is fed into an inkjet printer is placed into a paper tray, which is simply a small plastic tray in the front of the printer that holds the paper until it is fed into the printer by the paper-feed mechanism. On smaller printers, the paper is placed vertically into a paper feeder at the back of the printer; it uses gravity, in combination with feed rollers and separator pads, to get the paper into the printer. No real rhyme or reason dictates which manufacturers use these different parts; some models use them, and some don’t. Generally, more expensive printers use paper trays because they hold more paper. Figure 11.8 shows an example of a paper tray on an inkjet printer.

The final parts of the paper-feed mechanism are the paper-feed sensors. These components tell the printer when it is out of paper as well as when a paper jam has occurred during the paper-feed process. Figure 11.9 shows an example of a paper-feed sensor. Being able to identify the parts of an inkjet printer is an important skill for an A+ candidate. In Exercise 11.1, you will identify the parts of an inkjet printer. For this exercise, you’ll need an inkjet printer.

Control, Interface, and Power Circuitry

The final component group is the electronic circuitry for printer control, printer interfaces, and printer power. The printer control circuits are usually on a small circuit board that contains all of the circuitry to run the stepper motors the way the printer needs them to work (back and forth, load paper and then stop, and so on). These circuits are also responsible for monitoring the health of the printer and for reporting that information back to the PC.

The second power component, the interface circuitry (commonly called a port), makes the physical connection to whatever signal is coming from the computer (USB, serial, network, infrared, and so on) and also connects the physical interface to the control circuitry. The interface circuitry converts the signals from the interface into the datastream that the printer uses.

The last set of circuits the printer uses is the power circuits. Essentially, these conductive pathways convert 110V (in the United States) or 220V (in most of the rest of the world) from a standard wall outlet into the voltages that the inkjet printer uses, usually 12V and 5V, and distribute those voltages to the other printer circuits and devices that need it. This is accomplished through the use of a transformer. A transformer, in this case, takes the 110V AC current and changes it to 12V DC (among others). This transformer can be either internal (incorporated into the body of the printer) or external. Either design can be used in today’s inkjets, although the integrated design is preferred because it is simpler and doesn’t show the bulky transformer.

The Toner Cartridge

The EP toner cartridge (see Figure 11.10), as its name suggests, holds the toner. Toner is a black carbon substance mixed with polyester resins to make it flow better and iron oxide particles to make it sensitive to electrical charges. These two components make the toner capable of being attracted to the photosensitive drum and of melting into the paper. In addition to these components, toner contains a medium called the developer (also called the carrier), which carries the toner until it is used by the EP process. The toner cartridge also contains the EP print drum. This drum is coated with a photosensitive material that can hold a static charge when not exposed to light but cannot hold a charge when it is exposed to light—a curious phenomenon and one that EP printers exploit for the purpose of making images. Finally, the drum assembly contains a cleaning blade that continuously scrapes the used toner off the photosensitive drum to keep it clean.

The Laser Scanning Assembly

As we mentioned earlier, the EP photosensitive drum can hold a charge if it’s not exposed to light. It is dark inside an EP printer, except when the laser scanning assembly shines on particular areas of the photosensitive drum. When it does that, the drum discharges, but only in the area that has been exposed. As the drum rotates, the laser scanning assembly scans the laser across the photosensitive drum, writing the image onto it. Figure 11.11 shows the laser scanning assembly.

High-Voltage Power Supply (HVPS)

The EP process requires high-voltage electricity. The high-voltage power supply (HVPS) provides the high voltages used during the EP process. This component converts AC current from a standard wall outlet (120V and 60Hz) into higher voltages that the printer can use. This high voltage is used to energize both the charging corona and the transfer corona.

DC Power Supply (DCPS)

The high voltages used in the EP process can’t power the other components in the printer (the logic circuitry and motors). These components require low voltages, between +5VDC and +24VDC. The DC power supply (DCPS) converts house current into three voltages: +5VDC and –5VDC for the logic circuitry and +24VDC for the paper-transport motors. This component also runs the fan that cools the internal components of the printer.

Paper-Transport Assembly

The paper-transport assembly is responsible for moving the paper through the printer. It consists of a motor and several rubberized rollers that each performs a different function.

The first type of roller found in most laser printers is the feed roller, or paper-pickup roller (see Figure 11.12). This D-shaped roller, when activated, rotates against the paper and pushes one sheet into the printer. This roller works in conjunction with a special rubber separator pad to prevent more than one sheet from being fed into the printer at a time.

Another type of roller that is used in the printer is the registration roller (also shown in Figure 11.12). There are actually two registration rollers, which work together. These rollers synchronize the paper movement with the image-formation process in the EP cartridge. The rollers don’t feed the paper past the EP cartridge until the cartridge is ready for it.

Both of these rollers are operated with a special electric motor known as an electronic stepper motor. This type of motor can accurately move in very small increments. It powers all of the paper-transport rollers as well as the fuser rollers.

The Transfer Corona Assembly

When the laser writes the images on the photosensitive drum, the toner then sticks to the exposed areas; we’ll cover this in the section “Electrophotographic (EP) Print Process.” How does the toner get from the photosensitive drum onto the paper? The transfer corona assembly (see Figure 11.13) is given a high-voltage charge, which is transferred to the paper, which in turn pulls the toner from the photosensitive drum.

Included in the transfer corona assembly is a static-charge eliminator strip that drains away the charge imparted to the paper by the corona. If you didn’t drain away the charge, the paper would stick to the EP cartridge and jam the printer.

There are two types of transfer corona assemblies: those that contain a transfer corona wire and those that contain a transfer corona roller. The transfer corona wire is a small-diameter wire that is charged by the HVPS. The wire is located in a special notch in the floor of the laser printer (under the EP print cartridge). The transfer corona roller performs the same function as the transfer corona wire, but it’s a roller rather than a wire. Because the transfer corona roller is directly in contact with the paper, it supports higher speeds. For this reason, the transfer corona wire is infrequently used in laser printers today.

Fusing Assembly

The toner in the EP toner cartridge will stick to just about anything, including paper. This is true because the toner has a negative static charge and most objects have a net positive charge. However, these toner particles can be removed by brushing any object across the page. This could be a problem if you want the images and letters to stay on the paper permanently!

To solve this problem, EP laser printers incorporate a device known as a fuser (see Figure 11.14), which uses two rollers that apply pressure and heat to fuse the plastic toner particles to the paper. You may have noticed that pages from either a laser printer or a copier (which uses a similar device) come out warm. This is because of the fuser.

The fuser is made up of three main parts: a halogen heating lamp, a Teflon-coated aluminum-fusing roller, and a rubberized pressure roller. The fuser uses the halogen lamp to heat the fusing roller to between 329° F (165° C) and 392° F (200° C). As the paper passes between the two rollers, the pressure roller pushes the paper against the fusing roller, which melts the toner into the paper.

Printer Controller Circuitry

Another component in the laser printer that we need to discuss is the printer controller assembly. This large circuit board converts signals from the computer into signals for the various assemblies in the laser printer using a process known as rasterizing. This circuit board is usually mounted under the printer. The board has connectors for each type of interface and cables to each assembly.

When a computer prints to a laser printer, it sends a signal through a cable to the printer controller assembly. The controller assembly formats the information into a page’s worth of line-by-line commands for the laser scanner. The controller sends commands to each of the components, telling them to wake up and begin the EP print process.

Ozone Filter

Your laser printer uses various high-voltage biases inside the case. As anyone who has been outside during a lightning storm can tell you, high voltages create ozone. Ozone is a chemically reactive gas that is created by the high-voltage coronas (charging and transfer) inside the printer. Because ozone is chemically reactive and can severely reduce the life of laser printer components, many older laser printers contain a filter to remove ozone gas from inside the printer as it is produced. This filter must be removed and cleaned with compressed air periodically (cleaning it whenever the toner cartridge is replaced is usually sufficient). Most newer laser printers don’t have ozone filters. This is because these printers don’t use transfer corona wires but instead use transfer corona rollers, which dramatically reduce ozone emissions.

Duplexing Assembly

Any laser printer worth its money today can print on both sides of the paper (as can some nicer models of inkjet printers, mentioned earlier). This is accomplished through the use of a duplexing assembly. Usually located inside or on the back of the printer, the assembly is responsible for taking the paper, turning it over, and feeding back into the printer so the second side can be printed.

Step 1: Processing

The processing step comprises two parts: receiving the image and creating the image. The computer sends the print job to the printer, which receives it via its print interface (USB, wireless, etc.). Then, the printer needs to create the print job in such a way that it can accurately produce the output.

If you think back to our discussion of dot-matrix printing earlier in this chapter, you might recall that dot-matrix printers produce images by creating one strip of dots at a time across the page. Laser printers use the same concept of rendering one horizontal strip at a time to create the image. Each strip across the page is called a scan line or a raster line.

A component of the laser printer called the Raster Image Processor (RIP) manages raster creation. Its responsibility is to generate an image of the final page in memory. How the raster gets created is dependent upon the page description language that your system is using, such as PostScript (PS) or Printer Control Language (PCL). Ultimately, this collection of lines is what gets written to the photosensitive drum and onto the paper.

Step 2: Charging

The next step in the EP process is charging (see Figure 11.15). In this step, a special wire or roller (called a charging corona) within the EP toner cartridge (above the photo sensitive drum) gets high voltage from the HVPS. It uses this high voltage to apply a strong, uniform negative charge (around –600VDC) to the surface of the photosensitive drum.

Step 3: Exposing (Writing)

Next is exposing the drum to the image, often referred to as the writing or exposing step. In this step, the laser is turned on and scans the drum from side to side, flashing on and off according to the bits of information that the printer controller sends it as it communicates the individual bits of the image. Wherever the laser beam touches, the photosensitive drum’s charge is severely reduced from –600VDC to a slight negative charge (around –100VDC). As the drum rotates, a pattern of exposed areas is formed, representing the image to be printed. Figure 11.16 shows this process.

At this point, the controller sends a signal to the pickup roller to feed a piece of paper into the printer, where it stops at the registration rollers.

Step 4: Developing

Now that the surface of the drum holds an electrical representation of the image being printed, its discrete electrical charges need to be converted into something that can be transferred to a piece of paper. The EP process step that accomplishes this is developing (see Figure 11.17). In this step, toner is transferred to the areas that were exposed in the writing step.

A metallic roller called the developing roller inside an EP cartridge acquires a –600VDC charge (called a bias voltage) from the HVPS. The toner sticks to this roller because there is a magnet located inside the roller and because of the electrostatic charges between the toner and the developing roller. While the developing roller rotates toward the photosensitive drum, the toner acquires the charge of the roller (–600VDC). When the toner comes between the developing roller and the photosensitive drum, the toner is attracted to the areas that have been exposed by the laser (because these areas have a lesser charge, –100VDC). The toner also is repelled from the unexposed areas (because they are at the same –600VDC charge and like charges repel). This toner transfer creates a fog of toner between the EP drum and the developing roller.

The photosensitive drum now has toner stuck to it where the laser has written. The photosensitive drum continues to rotate until the developed image is ready to be transferred to paper in the next step.

Step 5: Transferring

At this point in the EP process, the developed image is rotating into position. The controller notifies the registration rollers that the paper should be fed through. The registration rollers move the paper underneath the photosensitive drum, and the process of transferring the image can begin; this is the transferring step.

The controller sends a signal to the charging corona wire or roller (depending on which one the printer has) and tells it to turn on. The corona wire/roller then acquires a strong positive charge (+600VDC) and applies that charge to the paper. Thus charged, the paper pulls the toner from the photosensitive drum at the line of contact between the roller and the paper because the paper and toner have opposite charges. Once the registration rollers move the paper past the corona wire, the static-eliminator strip removes all charge from that line of the paper. Figure 11.18 details this step. If the strip didn’t bleed this charge away, the paper would attract itself to the toner cartridge and cause a paper jam.

The toner is now held in place by weak electrostatic charges and gravity. It will not stay there, however, unless it is made permanent, which is the reason for the fusing step.

Step 6: Fusing

The penultimate step before the printer produces the finished product is called fusing. Here the toner image is made permanent. The registration rollers push the paper toward the fuser rollers. Once the fuser grabs the paper, the registration rollers push for only a short time longer. The fuser is now in control of moving the paper.

As the paper passes through the fuser, the 350° F fuser roller melts the polyester resin of the toner, and the rubberized pressure roller presses it permanently into the paper (see Figure 11.19). The paper continues through the fuser and eventually exits the printer.

Once the paper completely exits the fuser, it trips a sensor that tells the printer to finish the EP process with the cleaning step.

Step 7: Cleaning

In the last part of the laser print process, a rubber blade inside the EP cartridge scrapes any toner left on the drum into a used toner receptacle inside the EP cartridge, and a fluorescent lamp discharges any remaining charge on the photosensitive drum. (Remember that the drum, being photosensitive, loses its charge when exposed to light.) This step is called cleaning (see Figure 11.20).

The EP cartridge is constantly cleaning the drum. It may take more than one rotation of the photosensitive drum to make an image on the paper. The cleaning step keeps the drum fresh for each use. If you didn’t clean the drum, you would see ghosts of previous pages printed along with your image.

At this point, the printer can print another page, and the EP process can begin again.

Summary of the EP Print Process

Figure 11.21 provides a diagram of all of the parts involved in the EP printing process. Here’s a summary of the process, which you should commit to memory:

1. The printer receives and processes the image and stores a page in memory.
2. The printer places a uniform –600VDC charge on the photosensitive drum by means of a charging corona.
3. The laser “paints” an image onto the photosensitive drum, discharging the image areas to a much lower voltage (–100VDC).
4. The developing roller in the toner cartridge has charged (–600VDC) toner stuck to it. As it rolls the toner toward the photosensitive drum, the toner is attracted to (and sticks to) the areas of the photosensitive drum that the laser has discharged.
5. The image is then transferred from the drum to the paper at its line of contact by means of the transfer corona wire (or corona roller) with a +600VDC charge. The static-eliminator strip removes the high, positive charge from the paper, and the paper, now holding the image, moves on.
6. The paper then enters the fuser, where a fuser roller and the pressure roller make the image permanent. The paper exits the printer.
7. The printer uses a rubber scraper to clean the photosensitive drum. At that point, it is ready to print the next page or it returns to the ready state.

Serial

When computers send data serially, they send it 1 bit at a time, one after another. The bits stand in line like people at a movie theater, waiting to get in. Old-time serial (RS-232) connections were painfully slow, but new serial technology (FireWire, Thunderbolt, and others) makes it a more viable option than parallel. While it’s quite common to see USB (another type of serial connection) printers on the market, it’s rare to find any other types of serial printers out there.

Parallel

When a printer uses parallel communication, it is receiving data 8 bits at a time over eight separate wires (one for each bit). Parallel communication was the most popular way of communicating from computer to printer for many years, mainly because it was faster than serial. In fact, the parallel port became so synonymous with printing that a lot of companies simply started referring to parallel ports as printer ports. Today though, parallel printers are becoming uncommon. The vast majority of wired printers that you see will be USB or Ethernet.

A parallel cable consists of a male DB25 connector that connects to the computer and a male 36-pin Centronics connector that connects to the printer. Most of the cables are shorter than 10′. Parallel cables should be IEEE 1284 compliant.

Universal Serial Bus (USB)

The most popular type of wired printer interface as this book is being written is the Universal Serial Bus (USB). In fact, it is the most popular interface for just about every peripheral. The convenience for printers is that it has a higher transfer rate than older serial or parallel connections, and it automatically recognizes new devices. And of course, USB is physically very easy to connect.

Ethernet

Many printers sold today have a wired Ethernet interface that allows them to be hooked directly to an Ethernet cable. These printers have an internal network interface card (NIC) and ROM-based software that allow them to communicate on the network with servers and workstations.

As with any other networking device, the type of network interface used on the printer depends on the type of network to which the printer is being attached. It’s likely that the only connection type that you will run into is RJ-45 for an Ethernet connection.

Wireless

The latest boon in printer interface technology is wireless. Clearly, people love their Wi-Fi because it enables them to roam around an office and still remain connected to one another and to their network. It logically follows that someone came up with the brilliant idea that it would be nice if printers could be that mobile as well—after all, many are on carts with wheels. Some printers have built-in Wi-Fi interfaces, while others can accept wireless network cards. Wi-Fi enabled printers support nearly all 802.11 standards (a, b, g, n, ac), and the availability of devices will mirror the current popularity of each standard.

The wireless technology that is especially popular among peripheral manufacturers is Bluetooth. Bluetooth is a short-range wireless technology; most devices are specified to work within 10 meters (33 feet). Printers such as the HP Officejet 100 mobile printer have Bluetooth capability.

When printing with a Bluetooth-enabled device (like a smartphone or tablet) and a Bluetooth-enabled printer, all you need to do is get within range of the device (that is, move closer), select the print driver from the device, and choose Print. The information is transmitted wirelessly through the air using radio waves and is received by the device.

Page-Description Languages

A page-description language works just as its name implies: It describes the whole page being printed by sending commands that describe the text as well as the margins and other settings. The controller in the printer interprets these commands and turns them into laser pulses (or pin strikes). There are several printer communication languages in existence, but the three most common ones are PostScript, Printer Command Language (PCL), and Graphics Device Interface (GDI).

The first page-description language was PostScript. Developed by Adobe, it was first used in the Apple LaserWriter printer. It made printing graphics fast and simple. Here’s how PostScript works: The PostScript printer driver describes the page in terms of “draw” and “position” commands. The page is divided into a very fine grid (as fine as the resolution of the printer). When you want to print a square, a communication like the following takes place:

POSITION 1,42%DRAW 10%POSITION 1,64%DRAW10D% . . .

These commands tell the printer to draw a line on the page from line 42 to line 64 (vertically). In other words, a page-description language tells the printer to draw a line on the page, gives it the starting and ending points, and that’s that. Rather than send the printer the location of each and every dot in the line and an instruction at each and every location to print that location’s individual dot, PostScript can get the line drawn with fewer than five instructions. As you can see, PostScript uses commands that are more or less in English. The commands are interpreted by the processor on the printer’s controller and converted into the print-control signals.

PCL was developed by Hewlett-Packard in 1984 and originally intended for use with inkjet printers as a competitor to PostScript. Since then, its role has been expanded to virtually every printer type, and it’s a de facto industry standard.

GDI is actually a Windows component and is not specific to printers. Instead, it’s a series of components that govern how images are presented to both monitors and printers. GDI printers work by using computer processing power instead of their own. The printed image is rendered to a bitmap on the computer and then sent to the printer. This means that the printer hardware doesn’t need to be as powerful, which results in a less expensive printer. Generally speaking, the least expensive laser printers on the market are GDI printers.

The main advantage of page-description languages is that they move some of the processing from the computer to the printer. With text-only documents, they offer little benefit. However, with documents that have large amounts of graphics or that use numerous fonts, page-description languages make the processing of those print jobs happen much faster. This makes them an ideal choice for laser printers, although nearly every type of printer uses them.

Driver Software

The driver software controls how the printer processes the print job. When you install a printer driver for the printer you are using, it allows the computer to print to that printer correctly (assuming that you have the correct interface configured between the computer and printer). The driver must be written specifically for the operating system the computer is using and for the printer being used. In other words, Mac clients need a different driver than Windows clients do, even to print to the same printer.

When you need to print, you select the printer driver for your printer from a preconfigured list. The driver that you select has been configured for the type, brand, and model of printer as well as the computer port to which it is connected. You can also select which paper tray the printer should use as well as any other features the printer has (if applicable). Also, each printer driver is configured to use a particular page-description language.

TCP Printing

Printers that are network aware need IP addresses, so it makes sense that you can add a networked printer by using TCP/IP, also known as TCP printing. Exercise 11.3 walks you through the general process of installing a TCP printer, using Windows 7 as an example.

Some installations will ask you which TCP printing protocol you want to use: RAW or LPR. RAW (also called the Standard TCP/IP Port Monitor) is the default, and it uses TCP port 9100 by default. It also uses the SNMP protocol for bidirectional communication between the computer and the printer. LPR is older, and the protocol is included for use with legacy systems. It’s limited to source ports 721–731 and the destination port 515.

After the printer is installed, it will appear in your Devices And Printers window just as any other printer would.

There are a few advantages to using TCP printing. First, it sends the print jobs directly to the printer, so your system does not need to act as the print server or spend processing time dealing with formatting the print job. Second, it allows clients with different OSs, such as Linux or OS X, to add printers without worrying about intra-OS conflicts.

Bonjour

Apple introduced Bonjour in 2002 (then under the name Rendezvous) as an implementation of zero configuration networking. It’s designed to enable automatic discovery of devices and services on local networks using TCP/IP as well as to provide hostname resolution. Currently, it comes installed by default on Apple’s OS X and iOS operating systems. Bonjour makes it easy to discover and install printers that have been shared by other Bonjour-enabled clients on the network.

Even though Apple developed Bonjour, it does work on other operating systems. For example, it comes with iTunes and the Safari browser, so if you have either of those installed on your, say, Windows computer, odds are that you have Bonjour as well. Once installed, the Bonjour service starts automatically and scans the network looking for shared devices. Exercise 11.4 shows you how to see if Bonjour is installed in Windows.

Bonjour only works on a single broadcast domain, meaning that it will not find a printer or other device if it’s on the other side of a router from your computer. All major printer manufacturers support Bonjour technology.

If you are using a Mac, adding a Bonjour printer is easy. You open System Preferences ➢ Print And Scan, click the plus sign under Printers to open the Add Printer window, and look for the printer on the list. If the Mac doesn’t have the driver available, you will be asked to provide it. Otherwise, you’re done.

In order to add or share a Bonjour printer from Windows, you need to download Bonjour Print Services for Windows. It’s found on Apple’s support site at https:// support.apple.com/kb/dl999.

AirPrint

The one big complaint that Apple aficionados had about Bonjour was that it didn’t support printing from iPhones or iPads. In 2010, Apple introduced AirPrint to meet that need.

The idea behind AirPrint is quite simple. Mobile devices can automatically detect AirPrint-enabled printers on their local network and print to them without requiring the installation of a driver. To be fair, what Apple really did was eliminate the need for a specific printer driver to be installed on the client and replaced it with the AirPrint concept. Then it was up to the printer manufacturers to develop their own drivers that talked to AirPrint. HP was happy to oblige with its Photosmart Plus series, and other manufacturers soon followed. The list of AirPrint-enabled printers is available at https://support.apple.com/en-us/HT201311. From the end-user standpoint though, no driver is required.

There really is no installation process, and printing is easy. Just be sure that your mobile device is on the same local network as an AirPrint printer. When you attempt to print from your device, select the printer to which you want to print, and it should work.

Printer Paper

Most people don’t give much thought to the kind of paper they use in their printers. It’s a factor that can have a tremendous effect on the quality of the hard-copy printout, however, and the topic is more complex than people think. For example, if the wrong paper is used, it can cause frequent paper jams and possibly even damage components.

Several aspects of paper can be measured; each gives an indication as to the paper’s quality. The first factor is composition. Paper is made from a variety of substances. Paper used to be made from cotton and was called rag stock. It can also be made from wood pulp, which is cheaper. Most paper today is made from the latter or a combination of the two.

Another aspect of paper is the property known as basis weight (or simply weight for short). The weight of a particular type of paper is the actual weight, in pounds, of a ream (500 sheets) of the standard size of that paper made of that material. For regular bond paper, that size is 17 × 22.

The final paper property we’ll discuss is the caliper (or thickness) of an individual sheet of paper. If the paper is too thick, it may jam in feed mechanisms that have several curves in the paper path. (On the other hand, a paper that’s too thin may not feed at all.)

These are just three of the categories we use to judge the quality of paper. Because there are so many different types and brands of printers as well as paper, it would be impossible to give the specifications for the “perfect” paper. However, the documentation for any printer will give specifications for the paper that should be used in that printer.

Many impact printers need to use special paper that has tractor feed perforations on the side or they will not work properly. When replacing tractor feed paper, it’s very easy to get it misaligned, and it will feed crookedly and ultimately jam the printer. Similarly, thermal printers also require special paper that needs to be loaded properly. In many cases, if you load it upside down, the unit will not produce images. By comparison, adding paper to a laser or inkjet printer is usually very easy!

Ink and Toner

The area in which using recommended supplies is the biggest concern is ink and toner cartridges. Using the wrong ink or toner supplies is the easiest way to ruin a perfectly good printer.

Dot-matrix printers use a cloth or polyester ribbon soaked in ink and coiled up inside a plastic case. This assembly is called a printer ribbon (or ribbon cartridge). Once the ribbon has run out of ink, it must be discarded and replaced. Ribbon cartridges are developed closely with their respective printers. For this reason, ribbons should be purchased from the same manufacturer as the printer. The wrong ribbon could jam in the printer as well as cause quality problems.

Inkjet cartridges have a liquid ink reservoir. The ink in these cartridges is sealed inside. Once the ink runs out, the cartridge must be removed and discarded. A new, full one is installed in its place. Because the ink cartridge contains the printing mechanism as well as ink, it’s like getting a new printer every time you replace the ink cartridge.

In some inkjet printers, the ink cartridge and the print head are in separate assemblies. This way, the ink can be replaced when it runs out, and the print head can be used several times. This works fine if the printer is designed to work this way. However, some people think that they can do this on their integrated cartridge/print head system, using special ink cartridge refill kits. These kits consist of a syringe filled with ink and a long needle. The needle is used to puncture the top of an empty ink cartridge, and the syringe is then used to refill the reservoir.

The final type of consumable is toner. Each model of laser printer uses a specific toner cartridge. You should check the printer’s manual to see which toner cartridge your printer needs. Many businesses will recycle your toner or ink cartridges for you, refill them, and sell them back to you at a discount. Don’t buy them. While some businesses that perform this “service” are more legitimate than others, using recycled parts is more dangerous to your hardware than using new parts. The reason for this is that refilled cartridges are more likely to break or leak than new parts, and this leakage could cause extensive damage to the inside of your printer. And again, using secondhand parts can void your warranty, so you’re left with a broken printer that you have to pay for. Avoid problems like this by buying new parts.

Hard Drives

For a printer to print properly, the type style, or font, being printed must be downloaded to the printer along with the job being printed. Desktop publishing and graphic design businesses that print color pages on slower color printers are always looking for ways to speed up their print jobs, so they install multiple fonts into the onboard memory of the printer to make them printer-resident fonts. There’s a problem, however: most printers have a limited amount of storage space for these fonts. To solve this problem, printer manufacturers made it possible for hard drives to be added to many printers. The hard drives can be used to store many fonts used during the print process and are also used to store a large document file while it is being processed for printing.

Trays and Feeders

One option that is popular in office environments is the addition of paper trays. Most laser and inkjet printers come with at least one paper tray (usually 500 sheets or fewer). The addition of a paper tray allows a printer to print more sheets between paper refills, thus reducing its operating cost. In addition, some printers can accommodate multiple paper trays, which can be loaded with different types of paper, stationery, and envelopes. The benefit is that you can print a letter and an envelope from the same printer without having to leave your desk or change the paper in the printer.

Related to trays is the option of feeders. Some types of paper products need to be watched as they are printed to make sure that the printing happens properly. One example is envelopes: You usually can’t put a stack of envelopes in a printer because they won’t line up straight or they may get jammed. An accessory that you might add for this purpose is the envelope feeder. An envelope feeder typically attaches to the front of a laser printer and feeds in envelopes, one at a time. It can hold usually between 100 and 200 envelopes.

Finishers

A printer’s finisher does just what its name implies: It finishes the document being printed. It does this by folding, stapling, hole punching, sorting, or collating the sets of documents being printed into their final form. So rather than printing out a bunch of paper sheets and then having to collate and staple them, you can have the finisher do it. This particular option, while not cheap, is becoming more popular on laser printers to turn them into multifunction copiers. As a matter of fact, many copiers are now digital and can do all the same things that a laser printer can do but much faster and for a much cheaper cost per page.